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Introduction
=te. Phyoical Setting Geology &Tules TIdal Salt Marsh Barrier Island Beach Characteristic Plants Characteristic Animals Offshore Natunl Reef Field Trip Safety TIps Site Information' Sapelo IsIa"d Glossary
From the mOl/ntains to the sea, GeOlg1a is hOllte to II remark-' able diversity ofplants (lnd 1 ani1!wls. Among the vast wildkmd trellSll1"f!S fi;ulId tbrougb 0111 thestllte, six spealll ecosys-
tenls bI/Ve been selectedfr' II
,mies ofNa!Und Crmmllmities ofGeM"J:,'ia Access Guides. The pll1pose ofthese guides is to enCOIlri/ge the entirepnnily to step out'lllld drjoy tlleSe special 1Ik,ces. U7hether yOIl are n:visiting aftvm1te site 01' investigating 1/W 71aNlral ffTellS, I hope these guides wilhnffease yom enjoyment and understanding ofGem'gills 11ch b..etitage ofnfltll11d CiJlmmmities.
The Nlltllraf Cmll1J1/t1Iities ofGeorgia series are part ofa CiJlnprebensive CiJlmllitmi!nt by tbe Georgia Department of Natuml Resources WiMlije Resourers Divisimj to proted, enhance, {//ulprollloteresprmsible use of011l' 'srate's resources. Other topics in this series , include: l{JlIglefJjpine-wiregrf/ss arnl1l/llllity, moulItllinCflVes, large nnd mlldl wetlrmds, lind ur1Jan prests. Erich access guide nmrlllarius mlljM" items of intet-est including geology, 1/fltural bistory, and ecology. (This series will CiJlnplement, not
repkfCe,y~urcboiceoffieM
gllides,wh~ch can provide ide1ltification keysJ
I 111J11J1ost appreciative of the mmty dedicated samtists, , field biologists, and educatm"S who bllVe cOlltJibuted thoughtjul mid valuable reviw COlll1J1mts a;ld mggrstions filr this guide, They have fill exhibited a spilit ofcoopemtioll lind det/ieatilJl/ to theirfieMs ofst/uly.
- Samh Mit(hell
o
the coastal areas. In the
southeast, cO:lStallands
are the flroduct of millions
of r..ears of weathering of
-the Appalachian
Mountains. Granite from the tops of these moun~
1 he lure of the Georgia
coast is timeless. From
Native Americans that first
tains has been caniedby rivers to the coast. This process of erosion continues to move sedime~ts
inhabited the barrier islands and coastal plain to the tourists of today, sooner I or later we all seem to be drnwn from inland cities to this captivating landscape. \hethet we seek artistic inspiration or a basket full of blue crabs for dinner, the coastal region offers us a rich bounty. Exploratio'ns of this region r~eal a natuml history forged by a unique combination of global position and envi ranmental issues.
In :I state of dynamic equilibrium, our coastline
is a constantly changing environment ruled by the unyielding forces of nature. Extending from mighty freshwater rivers to tran quil ocean reefs, coa~tal ecosystems have adapted to these demanding conditions and depend on and .support cach other. In spite of many challenges, Gcorb';a's salt marshes, tidal estuaries, sounds, barrier islands and offshore reef systems ha,roor diverse and ecologically important biolo&rical communities.
"While all regions change over time, few have changed as radically in recent geologic years,as .
from the mountains as well as shifting and sorting sands along the coast.
Where island meets the sea, ri\:er water mixes with the saltwater from the ocean. Under the influence of the tides, these brackish waters couple with the coastal landforms to fashion our present day estuaries, barrier islands and tidal marshes. Fertile estuarine waters and highly productive salt marshes dominate the intertidal zone of Georgia's coast.
Coastal waters that lie beyond the barrier islands harbor hardbottom reefs which rise from an otherwise barren ocean floor. Sandstone outcroppings form the natural reefs of the southeast c9ast which provide a habitat for communities of invertebrate animals such as sponges . and soft corals. In rurn these organisms attract .fishes, sea rurtles and other species that use the reefs for foraging and refuge.
Geor&ria's coast is indeed a land of diverse natural communities, so get ready to explore the ecosystems found within ollr coastal waters!
Georgt/l S((JdJ11i.,
/s a coll.rtauti} hOllgmg
em:iUJnmellt, ruled Iry the
IIIlJleldmg form
o!lll1tllre.
COASTAL WATl!FlS PHYSICAL Sli:TTING
divert most l:lrge storms
away from the east coast of
the United Stlltes in. the
spring and summer. The
Bermuda high can dimin-
ish the chance for rain by
hindering cloud develop
.. C .. MATE
ment and, if the high per-
sists. dry spells or droughts
( ....Iim:ne. the rear-to-}'ear
of persistence weather pat
can quickly develop. Annual precipitltion a\'er-
t~ms o,'cr time, phrsically
ages 133 em (52 inches).
conrrols the major habitlt
Average relative humidity
[c,rure; of Gewgia' i<more I ranges from 75% during
mannearcas.\\'atertem-
pcratures can be a primary
limiting factor in addition
to fluctuating salinity 1C\'el~
r ~:;'2~;~:;;:~d physically stressed emiron-
menlS. The coostal region
of Georgia has a subtropi-
cal climate, CharacteriZed.
by long, humid, and hot
summers and shan, mild
i1'
\J"J
wintcrs. In coastal GrorgJ:l, seasonal variation is considerablc, with temperatures
\""I.J noe .,. " " ranging from 5 to (41to91"F)."lempemtures
occasionally fall below
the day to more than 80% in the wamler months.
Exposure to the sun's rays wanns the land and water surfaces, but water temperarure does not increase as quickJy as land temperarure. \.vate~ absorbs and stores more of the sun's heat with less change in temperarure than almost all other liquids or solids. Accordingly, the oceans can store and release vast amounts of heat with little change in temperature. Temperatures in the sea seldom vary
more than loe (1.8oF) per
freezing during particularly
~
cold winters. Georgia's coast is
affected by frequent after-
U.
~
noon locally~produced (convectlo~l)1:hlln~Crspowers. The dJffercnual heat-
. ~ ing of land and oce.an dur-
""" ~ ing summer days results in
~~ thllnderstorms, which. are formed when moist air from the ocean is carried aloft in up-flowing currents of wann air over
~
land. At the same time, a high pressure system called the Bennuda high tends to
day or 10C (ISF) per season as compared with daily fluctuations of lOoe (181;') per day and Hoe (991;') per season on land. Though tidal salt marshes. estuarics. and intcrtidal beach zones have a veil of tater, they are primarily subjected to mles of the land, and air and water tcmperarures in these areas equalize rapidly.
Winds over the islands and estuaries are lighter than winds encountered in the open ocean. Offshore,lighf
COII.rlnl CeO/gill r .. ,ibh(Jpit'Dl climate .tr;vdlfLCS If}n.~, humid. hot .w;lInllerr follrr~'",l bv slum, 1J1iM ~inters.
winds ofless than 25 mph '(22 knOts, or 10 meters! sc(;ond) are measured from May until September. \oVinter storms (Nor'easter;;) gefl~rate stronger winds and correspondingly in aurumn and winter, winds above 25 mph are measured 30% of the rime.
Superimposed on daily weather patterns are large-scale tropical storms and hurricanes. The peaJ' t;ime for hurricanes is September and October, when the ocean temperature is the warmest and the hwnidity h'ighest. Major efecc;; of hurricanes are wind damage and Oooding from both rainfall and stonn wa.....es and tides. Falling pressure at the center of the-storm
can produce a storm surge which also causes flooding. Hurricanes are classified acco~gtotheir sustained wind speeds. Tropical storms measure wind speeds up to 75
mph (6fknots, 3? MIS), full hurricanes have wind
speeds greater than 75 mph. Georgia's proximity to the continental shelf anq the Gulf Scream affect the path ofhurriCincs. As hurricanes approoch the 9ulf Stream, they tend to shift nonhward, attracted to the warnl water currents of the Gulf Stream. As a result, Georgia is spared direct landfall-by a nwnber of hurricanes that enter the South Adantic Bight.
II" B .. ""I
1.1.. .. 111 DS
D" GCO"Ol .. :
GIIOI.OOle SIITTIIIIG
Gl."Orgias lower coastal
plain evolv(.x1 in response
to changes in climate and
ocean level. Vlind, water,
and tidal currents, are the
primary agents of
_ change in,the coastal
landscape, control-
ling the deposition and
movement of \'aSt
quantities of sand, silt,
and clay. Some of these
sediments were transported from other coastal
,
area!, but m~t originate from the Appalachian
Mountains. Physical and
I Itn: G T ISLnuJs mpptircJ rmu-h kmt III1IJ '11Mlltf_
chemical weathering of .
:JuJmg t!J~ grtflt t'gn
the mountains created
rocks of various sizes that
were reduced to smaller
particles. W'ind, water,
and gravity carried these
to the coast where they
mi.xed with existing
deposits to become p:lrt
of the now l)'pical beach-
es, dunes, marshes and
sound bottoms of
Georgia. Processes that
developed the coostal
plain are still at work,
maintaining:l dynamic
relationship belween the
land and ocean.
The Georgia coast-
line spans about 110 miles,
bordered in the north by
the Sav:lIUlah River and
the south by the St. Mary's
River. A well-develope,d
group of islands formed
..a chain along the coast,
and arc called barriers because they a~rb
wind and wave enerf,'Y
NOTES:
that would otherwlsc strike
die mainland unabated. Georgia's main barrier islands cO'lsist of an oceanfacing sand beach, a series of sand dunes, and a slig~k I~' e1e\'ated upland interior which is forested and may feature freshwater or salt-
water sloughs. Characterized by many winding tidal creeks, the s,'1rt marsh adjoins the islands' westem edge in most places and extends to the mainland shore.
Barrier island fonnation requires special coost31 conditions: a gently sloping sandy coost31 plain and . a slowly rising sea level. Georgia's barrier islands consi!lt predominantly of sediments deposi[ed during the Pleistocene Period, with a narrow strip of land on the OCClm side of fhe islands composed of more rccent Holocene deposits. Though there are different theories about how the islands and the sounds behind them fonned, one of the most likely explanations is that these islands werc created by a process known as mainland beach ridge drowning. The rise in sea level from the melting ice shects flooded the low areJS behind the ~ttl dunes, creating shallow sounds wbich separated the sand dunes from the mainland.
Five thous:md years ago, sea level rise slowed to a fairly constant ra[e of one foot per century. These conditions made it possible for these new sand dune islands to aCCUmU19[e
sediments, significantly increasing thcir-5ize. The islands continue to evolve, responding to the forces of wind and water. \i.mer stomlS, especiall}~nor'east ers, waml weather hurricanes, and a gradual rise in sea level keep these islands of sand in motion. The net effect of these forces fuels the gntdualmigration of the islands landward and southward. This process of island migration, or eros!on, generally occurs at a snail's pace, but clues begin to emerge after decades or cenruries. Evidence of this process can be seen in old peat deposits and fonner maritime forest tree stumps that arc now expost<d on the beaches of the barrier islands. h is also possible to find shells of estuarine organisms, such as oysters, on Georgia's barrier island beaches. The shells are actually fossils of organisms that lived in the sounds several thousand years ago that were exposed on the I be.aches as the islands moved westward. I
_I gel1t~y slop11lf{ constal pltim 111,,1 (/ slowly rising .\Cll /e'l.'el ar~ nece.ull1y. for tbe !o17!1atioll ofbonoier I>lllnd.~
SAND SHAItING SVlJTlt1'l'l
Fine quartz sands, trans poned by rivcrs from the upland Piedmont regions, make up the beaches and dunes of the Georgia coast. Partides of sand quickly respond to the dynamics of wave encrgy, moving offshore seasonally. During the wintcr months, sand is !M~t off the beaches by high
southerly direction by a
long-shore current. Georgias
barrier islands seasonally -
accrete (gain from another
area) from the north and
erode (lose through move-
ment to another area) to
the sourjl, supporting an
ever-changing shoretine.
These islands are considered
energy swnns. A single storm can transfer millions
dynamically stable; they gain, over time, aOOut as much sand
as they lose from erosion.
of cubic yards of sand to less
energetic locations. such as -
TI DI:.
an offshore sandbar. 'Ine
submerged sandbar accu-
Twice each lunar day, tides
mul:nes and stores sand.
sweep into coastal Georgia
During the less stormy
bringing with them nutrients,
summer months much of
plankton, and other aquatic
the sand rerurns to the
organisms which are vital
beach from the sandbar:
. to ~e overall productivity
This process is referred to
of our coastal salt m:ushes
as a sand sharing system.
and estuaries. And twice each
\\find direction and
lunar daY, the tides flow
speed, and the resulting
out of the salt marshes and
wave direction and force,
estuaries of coastal Georgia
determines the movement
Oushing nutritious decaying
of sand from beaches to
vegetarian and .sediments
offshore sandbars. During
into the ocean. lndeed, the
tr"Jnsport the sand grains
tides are the lifeblood of
are sorted by size and shape.
. our coastal ec6system.
\-\lind or water can carry
A prominent fearure of
particles and the distance
the Atlantic seaboard is an
moved is dependent on the
indented coastline called
velocity of the current and
the South Atlantic Bight.
the size, shape and density . ) Bordered on the north by
of the particles. As sand
Cape Hatteras, NC, the
b>Tains are deposited on the
South Atlantic Bight culmi-
beach from offshore, simi-
nates at Cape Canaveral,
lar sized and shaped partidC'l
FL. Between these twO
are grouped together. This
capes, the coast curves
_ sorting process contributes
gently westward to a point
to thc stability of the accu-
at approximately Brunswick,
mulatcd sands on a beach.
GA. Positioned at the most
Another ;spect of the
westward portion of this
sand-sharing system is
large indention in the coast-
illustrated by net movement
line, Georgia benefits from
of sand southward. Sand is
some degree of protection
gradually transported in a
from the open ocean.
The of 111O'i'C111rnt sand offihore betu:een sandbars and beaches is Imuu:n as the sand shoring system.
N QTlES:
TuiaflushnutritWus decPying vegctlltWn JnUisedimmtsintotbe
f"t'r'";"'hparboivtlidmint1gsfowohd lIS the sting f"IIJ.
The continental sJ)elf is 'widest at mid~Georgia, measuring approximately 100 Ian (54 nautieal miles), before it decreases in width northward toward the Carolinas and southward to Florida.
Oceanic tides and waves act upon coastal areas in very different ways depending on location and the shape of the landforms.. TIdes can be thought of as a long, progressive wave moving through the ocean. In the open ocean this bulge of water is about 0.75 to 1.0 m (2 to 3 feet) high. By the time large ocean waves meet the Georgia shore, they have traveled over an extensive, shallow contiilentai shelf, lOsing energy to friction along the way, As tidal water flows into the South Atlantic Big~t, the concave-shape of the coast, and the pro-
to gressively shallower basin
forces the water nood from the large open ocean i~to an increasingly smaller space. As the water mounds vertically, it creates tides in
Georgjathatare
the highest on
the Atlahtic Seaboard . south of
upe
COO. Georgia's coast above all is ruled by the tides. The average tidal range along the Georgia coast is approximately 2.5 m (7.5 feet). During a spring tide with favorable winds
we can ~xpericnce a rid;1 mnge of 3 m (9 feet) or more.
In contrast, North Carolina extends e<Jstward into the Atlantic Oceall, a position relatively dose to the edge of the (:ontinental
shelf and deep ocean water. This placement exposes its coastline to the unmitigated force of high energy Stoml ....'aves. Meanwhile, tidal waters now around the somewhat conve.~ coastline, causing tidal ranges along the shore that are about the same height produced in the open ocean. Tides only minimally affect North Carolina; instead, its coasts exist in a wave~ dominated environment.
The wQrd "tides" is a generic term lIscd to define the alternating rise an'd fall in sen level rclntive to Innd. TWQ prim,:uy forces deter~ mine the tides: the force of j grnvitntion exerted by the moon nnd sun upon the earth :md cCJltrifugal forces prodllccd by the revolutions of the earth and moon (an~ earth and sun) around their C0l111110n centers-of-gravity.
At the-surface of the earth, the canh's force of gravitational attraction
Uimdtr. grokrz;y lind bWVJgrcollnflllmm shtlpr IfJ"l>llllt<Jln tM(Ofl,rtul 41t tnIlrsb
Hf177,1l 7:..'flters of the GulfStream flou' northward, a rive1' u:itbin the sea 7.:..'hich traces tbe tOllt;nel1ta/ ,"'elf
acts in a direction inward toward its center of mass, and thus holds 'the ocean water confined to this surface. However, the gravitational forces of the moon and sun also act externally upon the -earth's surface waters. Their effects superimpose upon tpe earth's gravitatior:J.al-force and act to draw the ocean waters to positions,on the ear-th's surface directly beneath these celestial bodies.
Tides that occur during a full or new'moon phase are characterized by higher than a,,:,erage highs and lower man average lows. This happens because during these lunar phases the earm,-moon, and sun arc in line, and 'gravitational pull of the moon and sun is reinforced on the earths surface, These extra-high water levels appear as if . they "spring" from the earth and are called spring tides. During q~arter phases ofthe moon, the earth, moon, and sun are at right"angles to each other resulting in a "neap" tida! cycle of lower highs and higher lows decreasing the overall tidal rahg~.
IItb(}ughlilz'/rollmmwl tH)'('SIIIt'l'('1yhigb iiJlI/l illtmidJI!sySf(7!l.bsli/ol{iUlI
is (~etit'If)' aAo t't" y higb
AJong the coast of Georgia, expansive salt ,marshes monopolize the domain between the barrier islands and the mainland. 'Winding ribbons of tidal creeks and broad prairies of marsh grass form a transition zone between the salty ocean realm and the fresh,water,rerrestrial uplands. Remark~bly, Georgia holds approximately one-third Qf all the salt marshes on the Atlantic seaboard.
Thesaltmarshisa tidally inundated grassy wetland crossed and 'drained by a series of increasingly smaller tidal creeks. This dvnolmic area of brackis'h'to saline water is , bordered by shrubs and forests on the upland and by intertidal Illudflats, sand and oyster bars and open bodie~ of water algng the Imrsh edges. The environmental feamrethat distinguishes coastal salt marsbes'fromterrestrial habitats is flooding~all(l . draining of Imll:kish water, and accordingly' the tidal cycle acts as a p ,nary influence in the development ailQ .function of salt marshes.
NOTIli5:'
Several fuctors control the fonnatioll of salt marshes: a gently sloping coastll plain, the presence of bafrier islands, a high tidal r;:lnge, rivers which proVide fresbwater and sediment, low-energy waves, and a relatively stlble, or ,'cry slowly rising, sea.l~vel.
UN tCI..DING
ENV"ItON"CNTAI..
E~."'.NT5
Marshes dominate the tidal wetlands in Georgia. They can be found the entire length of the state along-a 4 ~o 8 mile wide snip winding around the edges of tidal w:l.ters. A'lany of the animals found in marshes arc visitors whOse arrival and departure is coordinated with the tidal cycle and! or time of day. Harsh and continually changing conditions in a salt marsh challenge residents amlsevereIy limit the time spent by opportunistic guests. This brackish water habitat only supports organisms uniquely adapted to sUlvive in a tidally stressed environment. Major factors ~uch as rapid changes in water levels from tidal floOding and draining, broad variation in temperaturc, and'fluctuating levels of salinity limit. the diversity of species in a salt marsh. Likewise, survival is a challenge in the marsh mud. as the densely packed llluddy sediments exclude oxygen and tend to concentrate salts from evaporating tidal water.
THIA\. eve ..... 0,. P"'OOD.INQ AND OItAINING
Rivers flowing through
terrestrial watcrsheds fol-
low the force of gravity in
a one-\\ ay IlllgratlOn to the ~ sea. In contrast, the
bi-directionalmovemcnt
of 'Yater within a saltmarsh
responds to the influence
of the tidal c}'c1~. Fresh
j watcr flows from the
uplands into thc marsh
where it mingles with the
nux imv:ard of ocean .water.
Precipitation, ri\'cr flow,
freshw:lter runofffrom
land, oceanic currents,
evaporation, and wind con-
tinually modify the volume
of water, level of salinity
and other water conditions
in a salt marsh.
Intertidal marslles are
shaped by. the twice daily
flow of water. One of the
most important results of
tidal flow into a marsh is
the formation of natural
IC\'ecs along the creek
banks: As flood-tide
waters carrying sediments
flow through tidal creeks
and spillover the banks,
'!idal lit mar: brr!IJl7n
the water velocity slows
on IIItl !a(r /1('1- rl th
:llld sands, clays, and silts
h ii-,. islands lind tb
settle from the W:ltcr.
iNaHMoud.
r-----..J--=
This deposition of sedi Illcnts ocCurs because the decreased velocity of tidal waters no longer holds the particles in suspension. As the levees increaSe in height only the highest tides flow over the top. Well developed levees channel tidal water farther into the marsh )'Ihere levees are less well developcd and the tidal water flows into the marsh and back behind the levees. As the tid:ll W:lters ebb, much of the water returns to die tidal creek, flowing b:lck _ MOlllld.the levec or slowly filtering through the marsh llluds. Ebb tide W:ltel"S' pool in depressions in the marsh surface. Brackish.water that remains on the surface of marsh muds SOCln c\'3porates or is taken up (mmspired) by pl:lnts leaving the salts behind. oVer time, the salt content of areas in the marsh can increase significandy producing salt pans or barreps.
The duration and depth of tidal flooding are critical factors In salt marsh zonation of plants. Marsh grass, Sp~rtilla alrl!1'7uiflol"ll, is the most prominellt' plant in southeastern marshes.From the' levce moving landward, thctallest Spanino gives way to its shorter form. Salt pans support few, if any, vascular plants; as thc elevation increases evcr so
slightly, glasswort (Snlicornia sp:), salrwort ' (Batis 71Ioritimo), and salt grass (Distich/is spicato)
emerge. As the I:ind slopes . upward, needle rush (J'IIIIClIS1"()f!'llIn'illllllS) and sea oxeye (Bon'icbill fmirm:ns) '.,.bound. . As elevation increases landward and tlie effects of salt water' flooding (Ire reduced, the diversity of plants and animals grows. Along "the landward edge of the marsh, ["\lin water counteraCts die infrequent flooding of brackish water. Sediment gradients also playa part in the amount of salt remincd in the marsh' mud: Clay, silt and s:.md are not equally distributed within the lllarsh ecosystem. 'Fine gr:t'ined marsh muds, clays an51 silt comprise 80% of the sediments in the low marsh; the remaining 20% is sand, High marsh sediments are 80% coarse sands with 20% clay and silt content. Coarse sands allow <Juicker pcrct>lation of water than finer muds, so the Sedinlenr size and type influences the amount of time brackish water sa:ands on the surlace of the marsh.
DRAWING!5:
Finc sediments tend to hold greater amount;s of salt than coarse grains and, O\'er time, high levels of salt can be measured with in the layers of marsh muds. Sandy, higher elevations promote thorough draining of tidal wat,::rs, :lnd little salt is Icft on the surfa'(;c or in thc upper layers of sediment._
Lmmense, deep oceans respond morc slowly than land sumces [Q changes in air tcmpeT3.ture. Tidal marshes-more land than pecan-respond quickly to shifts in air tempernture. A salt marsh :.vctland lacks woody vegetation and without trees to imer~ept the sun's rays and subdue storm winds, seasonal fluctuations in temperarure are far greater than the adjoining forestS. Seasonal temperature variation in both air and water can be extreme. Members of the salt marsh communitv are either able to cope with rapid temper arure changes in the tcmpcrarure of air and watcr or they migr:lte to other arcas until more favorable conditions return to the marsh.
\-Vater temperature, an important factor in regulating the activities and reproductive cycles of esruarine organisms, ~or mally range from about life (50F) in winter to 28e (82F) in swnmer.
Salinity, the mcasure of the salt content of water, exerts a significant influence on species composition of the residents in a salt marsh. S:llinity fluctuates daily (tidally~ seasonally, and with changes infreshwater runoff. It is expressed in parts per thousand (ppt), which is the number of parts of salt per thousand parts ofwatcror the total concentration ofsalt in grams.containcd in one kilogram of sea water. The salts are primarily sodium and chloride ions, supplemented by potassium~ calcium, magnesium, and sulfate ions, plus trace amounts of many other ions. Sca water in thc open ocean has a salinity of allproximatcly 35 ppt which distinguishes it from fresh water which has a salinity of less than 0.5 ppt. Estuarine waters, wmeh arc referred to as brackish, measure salinities between
0,5 and 30 I?pt. Salinities in salt marsheS range from 10 ppt to as high as 70 ppt in salt pans or salt barrcns.
Many marine and frcsh~ water animals are incapable of moving inw brackish' water or habit.1ts because they are desi~,'11ed to function within a narrow range of salinities. Saltwater -dehydrates us if we drink it because our system requires additional water to be pulled from our cells to dihu-e and excrete the salts that We in~ted in the saltwater.
of The COtist (,t'ory;ttl IS distil/[!,7/ishcd bv
bOlTier Islllluis fwd. e.\'teJlsh)e wetlflnd'! i.l'hlCb un' dfJwmntcd
by -"lit li"mhcs of vuooth ,oIJgrrl,\.I.
DRAWINGS:
Likewise, most species are made of cells that cannot tolerate much change in the fluids bathing them. Consequcncly, these animals soon die when they are inunersed in "an environment \vhere they cannot mainrnin their internal equilibrium. Marine animals have developed unique adaprntions in order to survive in a unifonnly salty med.iwn. Commonly, ocean dwellers lose salts until they have about the same salini-
ty as their environment. .Marine bonv fish, for
example, ha\'e~alized ceUsjn.~ gills that excrete salts taken in with seawater.
Freshwater animals mam-
uin approximately one percent of salts in their body fluids and continually rid -memseh-es of fresh 'water that enters their bodies, often through the process of releasing very dilute urine. Many hav.e special cells that can absorb s;tlts from. the environment and release them into the blood. Freshwater fish tend to take in c.l:CcsSivc amounts of
fresh water and lose too
much salt; they compensate by actively reabsorbing salts through speciali7.-ed cells in cllcirgills. ,
Despite fhe chaltenge, a fcw animals have adapted to thrivc in water with fluctuating salinities. These animals are able to regulate the salt concentr.!tions of their body fluids (osmoregulation) and keep them conStant despitc fluctuations in the environment.
For cxnlllple, the blue crab (C,dlil1ectes snpidus) main
tainsstable internal salt. cOllccntmtions while in brackish water bec:mse cells on its 6';l1s remove salt from the surrounding water and acti\'ely secr~te it into the blood while the excretory organs e1iminatc the excess water that ~n standy pours in. Blue crabs can ,thrive in waters that range in S<llinity from almost fresh to ocean
Pill JIll A III V
PItOOUCTION
Energy from the sun fuels photosynthesis, which allows green plants to con\'en the sun's energy into a fonn that can be utilized by animal org.misms. Green plants are the base of most food webs.in marine, freshwater, or terrestrial ecosystems. Alg<IC (simple, nonseed bearing plants) in the oceans make up the vast majority of primary production on the planet. Algae also contribute signiJicantly to the primary production in the salt rnarsh tidal creeks.
Phytoplnnkton, often referred to as the :'grass of the sea" because of their urili"'A1tiol~ by grazers of the food web, flourish in.a salt marsh. Diatoms, a type of single-~lled phytoplankton, arc found in abundance on thc mud surface. They Can be recognized by a thin golden film, in contrast to the graybbck of the lower layers of marsh mud.
Salt 1Jltirsht'S an b-/in'ed to be mllong. the most producti7.:f natural areas on e1l11h.
SPAIITINA,
DII:C:;OMPOSERS
ANO DI:TllllTU5
Smooth cordgrass, SpnrthlO nltt171iflom, is the moSt abundant and perhaps'the most well Immm coastll . salt marsli plant. Itis estimated that this species of Spnrtinn accounts. for near ly 90% of the vegetloon in the half million acres of salt marsh in coastal Georgia. Growing to 3 meters tlll (9 feet), it lives in salt marshes from . Tewfoundland to Florida and west to Texas.
Although brackish water stresses Sportinll, it fares better in thes:alt marsh that any of its competitors. Spnrtitlll stems slow the velocity of the tidal flo,\, causing sands, days, and silts to drop from the stream and settle near the base of the plant. Deposition of sediments also occurs:lS the f100dtide waters spread over the banks and water velocity is rcduced from a swiftly' , moving creek [Q a horizontal overflow. The geomorphology and the plant stems combine to create conditions that form a levee .-along the banks of the tidal creeks. Here, Spfl1tilln grows the tallest, aided by the twice daily flush of tides. A regular rinse of brackish water actually reduces the build up of salt in the low marsh. Higher elevations in the marsh are not flushed as regularly. Brackish water in
these places flows ovcr the levee :llld seeps down into the marsh mud whcre srnnds on the surface before evaporating leaving.thc salts behind. Hcre, Sparrilla growth is dwarfed or even rcplaced by other plants in high marsh areas. Spaltina has developed specialized adaptations that allow it to live in 5.111)' water, such as .glands on the leaves for , e:~pelling salt, and hollow stcms which move oxygen and carbon dioxide from thc lca\'es r,o the roots.
In thesah marsh, Spnrtinll provides the base for many food wcbs. However, few animals are able to digest the living plant (onJy ccrtain insects, crabs, and a few other animals can l:ireakdown the tough fibers of SfUmino). Instead, the dead stalks and Icavcs of the previous years growth arc consumed after the plants decompose. Decay bacteria break down complex molecules in plants and animals, making simpler molecules :wailable for usc by other organisms in thc ccosystem. Decomposed vegetatiQll"along with small bits of anim.,l relllflins, is known as detritus. The .. cOllversion of detritus to soluble compounds by microorganisms is necessary before the ~Iec<lyillg plants em be cQnsulllcd by detritivors. It is this detrital matter, a "vegetable soup" in the tidal creeks, that fuels the marsh system, adjacent tidal creeks, and areas offshore.
This enriched detritus provides a relatively constant food source year round. Primary produc~ rion in other ecosystems are often dominated by short bursts, calJed blooms, especially in the spring. D,etritus based (with associated microbes) food webs vary less seasonally than the more typieal bloom.-and bust cycles of plant production and succession.
Baaeria and fungi are significant primary decOmposers of plant material in the salt marsh and ocean environments. The nutritive value of Sportina increases as the detrital fragments -become enriched with microbial populations. The tiny particles of decaying Sportina form a substrate upon which micro-organisms gather. The micro-organisms im.Tease the digestibility of the [Qugh plam fibers, and :rdditionally, are nutritious themselves. A1b"aC (in addition [Q bacteria and other microorf,"anisllls) grows abundantly on detritus and \ many animals, such as crabs, -shril~lp, fish, 0)$ters, and mussels, feed on the enriched particles. The detritus caters may in tum become food for birds, raccoons, otters, minks, humans, and other animals.
B"ARICR ISLAND BEACH
5
\\-T ~
ind and water, and
~U ~~rci~:',~h~~:'
beaches in Georgia and
~
~.
around the world. These two physical forces move sediments that build, maintain, shift, and rebuild our coastlines in an ongoing dynamic balance.
Sand, transported by
water and wind, fonns
the characteristic wide,
.
: gently sloping beaches
'""d . that make up Georgia's
oceanfront. Sands are
transported from adja-
cent coastal areas shore-
~~ w"d by wove 'crion
~ from offshore bars or
~. .
from the sediments carried to the coast by freshwater rivers. Beaches, dunes and off-
shore bars constantly
~ , . I
~ 1\1JJ\.
excha.nge sands responding to the wind and nearshore currenrs. Bcc,",c of co,,"[ cnnfiguration and a broad, shallow continental shelr, wave energy along' the Georgia shoreline is low with wave heights averaging between 0.8
~
ancl 1.25 meters (2 and 4 fe t). \-Vind velocities of 12 mph or greater transport dried beach sand.
The height of the dune is detenn,ined by the size of . the sand gT~ins, wind velocity, and plant growth. Vegctation, particularly salt tolerant grasses, prove critical in dune building and stabilization of loose sedimcnts. Intersecting gnlss roots add to the stabilization of the dune. Over time, sand dunes are invaded by a succession of plant species..
Beaches protect the inland I areas by absorbing the major force of the wind, waves, and tidal currents. Dunes function as dikes against nooding from large ocean waves and as reservoirs of sand to seasonally replenish the beach. During hurricanes, dunes help reduce thc energt of Stonn "''aves..
Sea oatS in particular are so critical in maintaining healthy sand dunes that tHey are protected by law. It is iJIegal to pick sea oats and it is import:lnt not to damage the plants by walk, ing among them.
Piles of dead marsh grass, called wracks, are , transported by the tides and deposited on die beach front at the highest tide line.
'These wracks trap sand that-is washed and blown ashore, creating i foundation for duncs to fon11: Once sand has accumulated in tne wracks, plants uni(luely adapted to survive the harsh beach conditions establish a latticework of roots which further stabilize the loose piles of sand. Sea Oats, railroad vine, and marsh elder are some of the first plant'S to colonize the shifting sands. The pioneer plants provide essential nutrients such as nitrogen, and the \'egctati9nal debris increases the amount of carbon and moisture-holding humic material in the piles of sand. As growing conditions in the sand dunes impro\'e, additional plant types can become established. Ln this shifting, changing region some newly fonned dune systems mature through a succession of plants into a maritime forest, other dune fields wash completely into the sea in a single stonn. Over time, a dynamic equilibriulll presides over these coastall;ll1ds.
Bon-ifr Islond., ~'h/(b orp relnN ely
mt geolof!,/cal fa'P71liltlQm,
" uf the mann"
f i17l/ed behmd
'~he1ll {lre d.JnamlL olld (olltill~lOlIy chollging.
I
a: 0-"'"1: S".TI:M
M III' .... 001: Fo"
p, "
1 lants"~at survive in
beach areas have adapted
a to number of harsh envi-
ronmental fucrors. Sand dun~ are especially inhos pitable places for plants to grow as mey are hot and dry, COI1St:l1ltly subject to sah spray, fierce winds, and poor in mineral elements needed for growth. Because of these harsh conditions; coastal vegetation occurs in zones parallel to the coast, and sPecies abundance and diversity increases as onc moves inland away from thc extreme conditions on the beach. Many plants have successfully colonized the dunes and are responsible for maintaining the structure of the' dunes against the eroding action of wind and surf.
.0 II C M
ZON"II
Closest to the ocean is the beach and primary, or foredune, zone, which is finnly controlled by physical processes. Since storm waves or high tides rearrange the up'per beach every few years, this area is continually recolonized by plants. Beyond the lil~t of high
tide line, windblown sand
accumulates around the
plants and burial by sand is
a constlmt fuctor. One of the first types of plants to colonize the upper beach and newest dunes an~ the
lowgrowing, runners, such as the white-flowered beach morning glory (lpomoel1 st%"if~m) and the closely related purpleflowered railroad \~ne (lpomoel1 f16-11f?I1). Beach elder (11111 imbn"cntl1), sea . rocket (Cnki/~ ~dmmln), silverleaf croton (Croton pmutntlls), and beach orach (Atrip/~.:r!p.) ar.e among me early immigrants. This _
area also supports graslcs, such as sea oats (Unioll1 J1Onimlntil), bitter panic grass (Pnnim11l ilmm7nn), salt meadow cordgrass (SpnTtinl1 PllteJIs) and a few other herbaceous plants that
can tolerate exposure to s.-tlt Spr:.1Y and shifting sands.
An interdune meadow or mmsitional wne is situated between the front and back dunes. L1rge areas of barren sand, sclttcred shrubs, and-patches of grasses ;lIld .
herbs characterize the interdune rne:ldow. This
broad n:lt :lrca suppOrts
low growing grasses and
~~
NOTES: DRAWI".GS:
forbs, such as beach pennywort (H)'drocot)'le /101/111'ieusis), dune primrose (Oellotbembll711ijllsa), matchstick (PbyJo nodiflora), yeUow-flowered camphorweed, golden aster (Hete1'otbeca sp.), and blanket flower (GailJonJia plllchelJo), Spanish bayonet (YtlCca sp.), prickly pear cactus (Oplf1ltia sp.), sandspur (CMcbnlS tTibllwida), saltmarsh cordgrass, and muhly grass (k]ublen4 bergia cnpi1Joris).
Landward of the interdune meadow-is the backdune zone, which supports broadened community diversity including shrubs and vines as .....ell as grasses and other herbaceous plants. Vines include catbriar (Smilax sp.) and butterfly pea (CHtoria mariana), Virginia creeper (ParthmoWstlS 1I1inQllrfOHa), pepper vine (Ampewpsis arbfn-ea), and wild grape (Vilis rp.). Inhabitants of me interdune meadow are common in the backdunes include dune primrose, yellow-flowered I.:-amphor-
weed, golden aster, and blanket flower. Wax myrtle (Myrim a:riftm), red bay (Pi"/"Set/ bmwlIia), and yaupon holly (liex vomitorin) are the succeeding dominants.
F;lrthest from the ocean is the maritime forest wne, which nurtures the greatest diversity and a number of woody plants such as pines and hardwoods.
Salt spray is an important environmental factor limiting the growth of
phlllts on coastal sand dunes. As waves break on the beach, winds pick up and carry droplets of salt water inland. Salt spray blows onto the front-line plants, effectively pruning the new gro\\~ng tips. Some of the water evaporates from the salt spray as it 6 blows inland and the salt crystals drift to the ground. Salt inhibits the growth of many beach plants, especially those growing nearest the ocean.
SIA OA"
(UnioJoplmimJow) Sea oats are the most important aDd widespread grass on southern coastal dunes. This tough perennial grows to a height pf 14 2 meters (3-6 feet) and ' may be recognized by its oat-like flowers or panicles. The seed heads mature in
autumn. They arc compressed spikelets borne at the end of stiff stems 1 meter ~3 feet) long or more. Its pale green IC)lvCS arc long and narrow, measuring less than 1.5 centimeters (0.5 inches) in width. . Drought resistant and
immune to some funb'lIS infectiOns that pl3b'1JC othcr grasses, S63 03ts arc
especially hardy pbnts. Sand that collects
around the plant stimulates plant growth. The cycle 9f sand collection and plant growth facilimtes expansion of both the sea oats and the sand dune. 1. a sea oat is buried by sand, it develops vertical rhiwmes
.m hedfh are7S
ha" adopted to .""wllber ofharsh em.:ir()l11l1tJltnl farton"
DRAWIN.GS:
(underground stcms) which grow to the surface producing an of-fupring plant. Primary dune systems - that have been cut away by hurricanes reveal "original c1wnps of sea oats in die dune profile with underground stdns (rhizomes) and roots reaching up to 9 meters (30 feet) below the top of the dune. The fibrous roots of these plants usually extend to the upper pans of the water table, some 11 meters (40 feet) below me dune's peak in some places. The vertical taproot alone can grow up to 3.5 meters (12 feet).
Complementing the network o(roots underground, sea oat leaves and stems trap wind-blown sand, thus increasing the size pf the dunes. Above ground stems continually flex in the battering wind or under the weight of a foragi.ng red-wing blackbird. Leaves often bend to the ground and dig shallow crescents in the sand as they rotate in the Yo1nd. These depressions then catch the seed heads that f~ll in the late summer and keep th~m from blowing away. Seedlings' that have been covered by a moderate amo'um of sand grow more quic1}1y than those that are left exposed. It is thought that the sheltering sand insulates the infant plant against too much h,eat and desiccation. However, sea oatS primarily propagate new growth by underground rhizomes.
BI:ACH"MoItNING GI,.OIt'V
& RAIl.:ItO ... O VINI:
(lpomoensp.) B,each morning glory and railroad vine occur on dunes throughout the south Atlantic and Gulf region. The stems of these perennials are thick, fleshy and f1enble, and may extend across the ground 25 meters (75 feet). The leaves are shaped like a rounded hean ( I. pescaprae); arc long stalked, either unlobed and oblong, or are broad and ha\'e three or five round-ended lobes (I. n%if"a). Beach n~om ing. glory has white flowers, appe:lring in early summer, flowers on the railroad vine are purple, bloomjng in late summer and autumn.
B
E
(Iva imbricntn)
The sparse woody stems of
seashore elder grow more
or less upright,. 0.5-1.25
meters (fA feet) tall. The
le:lVes are fleshy, narrow,
and lance shaped, ",",hen
buried by sand a stem
develops into a strong sys-
tem of rhizomes and routs.
S"'I,. "I A ItSH
CORP It .....
(SPtll11I1ilPflfCl/S) , Saltmarsh cordgrass is an especially salt tolerant plant. Stcms are slendcr and grow 1 meter tall (3 feet). Leave:; arc rolled inward and resemble rushes. Seed heads are composed of two to sevcr:ll compressed spikes attached at ncarly a right angle to the stem. ,
-Pnrosli.t .-oyslt'ms r-
t:ta 11.1 {ormll wttle ~ rn-J.. th1tgr(1mfrrm h
ott '7loft}cilune ffnbilizing tbe 100.1"<' SlInd.> ,{sma!1 ilm! ~v()I/I/g {md !{/IX<' Imd old dlllln, ,lIiJ.:I'
Though viable seeds are produced, this plant most commonly spreads by a net ~'ork of slender rhizomes.
BITTIEIIt P Nle. Gilt .....
(pollinm1omon",l) Biner panic grass is a some what dense, upright perell ni~l bunchgrass on coastal dunes. 111e stems are coarse, straight, stiff, and up to 1.25 meters (4 feet) tall. Seed heads are' narrow, compressed and generally sparsely seeded. Plants spread from aggressive scmered system of rhizomes..
BLIPoNI(IET FLOWIEIIt
(Gnillordio pukhrllo) Blanket flower, sometimes called firewhecl, is a perennial that occurs on coastal dunes in the lower south. Plants are generally 0.5 meters. (18 inohes) tall. Leaves arc narrow, commonly sharp toothed, appear singly and measure about 8 on (3 inches) long. l11e brightly<olored flowers commonly have crimson or purplish centers and yellow rays and bloom throughout the summer .and early autumn.
PR I K LV P IlA R
CACTUS
(OpUlltif/sp'; Prickly pear cacti are native to coastal dunes throughout the south Atlantic and Gulf region. Prickly pear cacti grow to a height of about 2 meters (6 feet). The trunk is short and bushy with branches of flat, oval, or oulong fleshy joints.
These joinrs, thick and green, arc connected endto--end and am'led with spines. The flowers are very showy and bright yellow in color. The pear-shaped edible fruirs arc purple to red in color and covered by bunches of shon bristles.
SPANISH BAVo..NET
(}1ICCIISp.) Easily recognizable by irs 100lg green spiky leaves that resemble the bayoners used by ground soldiers, this plant is supremely adapted, for life in the back dunes along the coast,. One of several yucca species, some gardeners include this pliant in their xeric (dry) landscapes; Spanish bayonet grows up to 3.5 meters (12 feet) tall with 0.75 meter (2.5 foot) long dagger-like leaves arranged'along a woody stem. Bottom leaves die off as the central stem grows longer. Be extremely careful around this plant: the lea'cs ha'e 'ery sharp points.
The-edible flowers of Spanish bayonet bloom May through July. Each blossom has six creamy . white petals and a sweet fragrance which attracts the Yucca moth, the plant's prime pollinator. After pollination, 5-10 centimeter (2-4 inch) cucumbershaped fruits develop. Black seeds and pulp fill the blackish-purple pods and those that don't pro-vide food for the Yucca moth caterpillars fall to the ground to germinate.
III Keolog/cul terll1, /'orrier isiamls an: tbe among flIt! //lost ephevlemI of , habitat,i', Shordilles fire continlllti~y
trt/~1:,foJ7J1e11'Y ""u/I ""OIUtlO1l alld
sen ",'"L'ei cbfmges.
NOTES:
,.
DRAWINGS:
Hilitoric..":llly, the fibrous lea\'cs or the yucca wcre used by coastal Native Amencans in weavi'ng baskets, rope and sandals; its tough rootS we~ used as a water source as well as raw material for soap-making.
M"'''ITI'''I: FOIIEST
Geor~..ias wide, short barrier islands are uniquely suited for the csrnblishmcnt of extensive maritinle forests. Siruated in the South Atlantic Bight, the coast of Georgia is a !ide-<lOlninated environment with wide, gently sloping beaches and established sand dunes on .the eaStern from, and extensive tidal salt marshes on the mainland side of barrier islands, Maritime forests thrive in upland 'areas ofa barrier island'" which are prote<:t~d from shifting sands and salt water flooding. Sand dunes divert winds and salt water creating relatively srnble condirions leeward.
Even on rel~ti""e1ystable barrier islands, conditions are consrnntly changing so . the transition from backdune or marsh to maritime forest shifts accordingly. Moving into the transition 7.one between marsh and' maritime forest you will see black needle-rush (ftIIU1JS rDnllerinllPS}; sea 'ox~'e (BorridJin frutn1ts), groundsel (Bnabllris holi",;folia), wa.\': mynle (Myrica em/tra), saw palmetto (5n-rn0n rtpt.>ns), palm (~ba/ pa/ml.'tto), yaupon
holly (/lex oo1l/;torio), and red cedar (Jrm;ptr sp.).
lnside the maritime forest, environmental factorS arc a world apart from condit;ions on the beach. Two primary factors influence this difference: geology (substrate or soils) and plants. Once plant succcs~ion begins, it is the plants of the maritime forest that modify the environment. Large trees, particularly . live oaks, provide a canopy that shades sunlight, slows wind velocity, retains mois-
ture and contributes organic matter to the soil. Plants
r maintain cooler tempcranlres in the SUlluncr "through the process of transpiration' and by providing shade. In addition, they keep tcmper:ltures from dropping ,IS low :IS be:lch temperatures 'by rcdlicing the wind speed. Thc process of transpiration also increases the moisture in the air and soil in a forest.. Barrier island soils are typically I;rgely made up of medium to fine sand grains :lnd are very poor in nutrients. As plants'flourish\on the islands they contribute both nutrients and organic matter, which increases the moisture holding ability in 'the soils. The leaf litter ' am:! other organic matter b.::,eaks down quickly in the soils due to long periods of high temperatures and high moisture levels.
PI,mrs of rbt' IJIlwirwll.'
jon'sf moJifi fbI' VIVI7"/J1I'Iflit Irr pn 'iJing fhadf
nn
;.
I DRRW,.O.,
Almost' year-round decom-
.position of plant debris
provides nutrients that are
:lVailable on a relatively,.
consistent basis. So despite
relatively poor island soils,
an adequate supply of
nutrients, organic maner
and moisture in the mar-
inllle forest supports a lush
understory of plants.
.
The climax stage in a
maritime forest Communi-
ty is characterized by live
oaks (Qtlm14S virgilliollQ).
This long-lived giant is the
state tree of Georgia:
Alassi,'c trunks and large,
horizontally spreading
branches 3rc typical, and
many mature live oaks
have a crmm spread of
more than 50 meters
(150 feet). A well devel-
oped root system anchors
..the trees in the sandy soils
and taps into underground
sources of-freshwater.
Sturdy trunks with twisting
branches withstand even
gale-force winds. Live oak
trees have developed
thickened, l~athery leaves
topped with a waxy coating
which reduces the effects
of drying conditions, salt
spray, and wind shear.
Salt spray does, howev-
er, alter the shape of oaks
growing ncar the ocean.
As the waves oreak,
droplets of salt water are
Glrried by onshore winds
to the tree branches. Salt
spray kills the growing
tips, causing the tree to
appear pruned by the
ocean winds. The charac-
teristic wedge shape pf the
pruned trees are flattened .
..
on the ocean side and most of the new growth continues on the leeward side of the tree.
Live oak timber is one of the heaviest of the native hardwoods and is resistant to roning and weathering. It was lumbered extensi\'c1y for shipbuilding during the 18th and 19th centuries because of the natural _
cun'cs found in the lower ...trunk and limbs of the
trees, andthe strength of the wood. Our nation's first publicly-owned timberlands, purchased for the I avy's shipyards, were live oak forests on the Georgia Barrier Islands.
'lassive trunks ,md Imge. hori:.ollta/~y spreading , branches are typiml . ofthe Ih-e oak, GeOlogia s-mojestie state tree.
S"'L.T"''''RSH Al'u",,,,L.S
The intertidal zone is a
transitional area between
uplands and pennanently
flooded estuaries and bays.
Thus the intertidal zone
includes areas that adjoin
uplands (and are only
occasionally flooded by sea-
....'ater) as well as the lower
portions of the intertidal
zone.....'hich are infrequently
exposed to air. Consumers
. that use the intertidal zone
include both terrestrial.and
U
~
marine organisms Some animals are
pennanent residents In
"l"~""h"". VlSltOrs, someostheaes"onmally
(such as nugratory birds).
some only at high tlde,
others only at low tide,
some at partlcular stages
of their life cycle, many only occasionally For
aJ some speCies the saltmarsh IS essential habitat and
f ) others use the salt marsl1 , opportUl11StlCaUy, arnvlllg
to take advantage of the
'abundant food sources.
Tides entering a marsh
usher in a host of animals
that feed on small fish,
invertebrates and each
other. As the tidal waters
return to the se:l, birds
and mammals enter the
marsh and prey on ani-
mals now exposed in the
shallow cl:eeks.
The charn<..'tCristic animals are fiddler crab~ (UCif sp.), shore crabs (StSllrmll sp.), blue crabs (CnlNl1cettS sp.), mud crabs (Pnllopells sp. &EmytiIOILsp.), mussels
(Gtllkmsin sp.), periwinklcs (Litto,-i"n sp.), mud sr]aiis
(llyanassa !p.), and sediment
dwelling worms 0mphinire '1', '" Hnp"',ro/Qp"'''p.~The landward edge of the marsh
supports populations of the wharfcrab (Sesnmrn
ci1lutllm), the coffee bean snail (Mtlnmpus sp.) and the
beachhopper (Orcbtstia griUIIS). The bIadcs and stems of Spnrti1la support a small bamade (Cbtbu71lllllisfragila).
c
(Cullintcltssppi,Jtls) "BeautifQ! swimmers" is the genesis for the technicl namc of the genus of the Atlantic blue crab (Callintctts) and, indeed, these crusrnceans arc' one of the fastest swimming crabs on the east coast. Agility and spe~d serve these predators well as they lic along the edgc of tidal creeks in the muddy sedimentS and ambush prey, including fish, fiddler cmbs :md odler invertebr.1tcs. Though they arc formidable predators, blue crabs ,llso will feed on dead and dying animals, and arc known to be cannibalistic. .
Blue crabs inhabit the tidal waterways throughout their entire life cycle. Not only arc the crabs tolerant of widely fluctuating salinities, they actually
Tb 'Munt/ebb (1"l1biJ Oi' o/thej;/StI'(tr;;'lIfidii/ (r"bs 01/ the toRst {(Jllrr
require various salinity
as a "soft shell crab" entree
ranges for particular times
on our dinner plate.
in their development.
Without protective covcr-
Mating takes place in the
ing, the crab is vuln"cpblc
upper esmaries where.
to other predators in the
males remain moS[ of their
tidal waters in addition to
lives. Fem;J[e blue crabs _
humans. The crab pumps
migrate to higher salinity
in water enlarging its soft,
areas in the lower estuary
still flexible shell and
or nearby ocean to spawn
waits until the shell hard-
:md then move back into tbe tTleanderi~g tidal
ens. In 24 hours the shell is "crinkly h~rd~' and
creeks: Blue crab eggs
within 72 hours after a
hatGh into planktonic larvae
molt the crab is once
and develop at sea before
again fully armored.
they migrate with ocean '
Male blue crabs are
currcnts back-into dle estll-
called "jimmies" and are
aries and tidal creeks. While
distinguished from felmles
in the ocean, crab lorvae -
by the flap on their
undergo several changes in
abdomen that is shaped
body shape, and arc still as
like the Washington '
small as the head of a pin whcn they have finally
Monument. Abdomen
Crab s!Jells are
flaps are modified tails (tel-
acquired ad~llt form. Molting is necessary for the cJ:abs to become mature adults.
sons) that evolved to fold
under the crab's body and I;rotect repro~luctive organs. Maturt female
made ofchitin, a'material similar
Crab shells are made of chitin, similar to the mater-
blue crabs, callcd "soaks," have a semi-circular shaped'
to fiJlg~17znils.
ial in fingemails.This
abdomen flap, Illuch like
hardened suit of annor pro
the silhouette of the
vides ample protection, but
Capital Dome, which is
limits the (:rabs ability to
speci:llly adapted to hold
grow Iarbrcr. Casting off a
developing egg maSSC$.
constricting shell and pro-
Fqnales ;ue also distin-
ducing another is referred'
guished from the (nales by
to as molting, a process that
their claws with bright red
i
occurs 20 or more times in a crab's life. MQlting begins
tips. Immature females have a wide "V" on thcir
with a split between thc top
abdomen flaps and are
and bottom of thc shell at
known as "sallies."
"
the t.1il which allow~ the
Eyes on the blue crab
crab to back out of the
are mounted on stalks
discarded shell. The
which provide 3600 vjsion
I
process is similar to you
.and can retract when
pulling a tight sweater off
threatened. The flattened
I
oyer your hcad. At..this
shell of the.blue crab is
stage the crab is covered
wider than it is long al)d
,I
only with soft ti.ssue and
has an extended point or
I '.
may be,most familiar to us
-spike on each side.
t';I----------...,I:---:...--'---------,--1
NOTE.S: DR"'WINGS:
UnJike its name implies, the blue crab is actually mostly an olive-green color; blue only is found on the claws and legs, Pans of the claws and spines on the shell are red to orange and the undersides arc white.
BlI:"'CH
I MYlI:ttT -tt ... TlI:S
The intertidal beach habitat extends from the extrenu~ low spring tide mark to the extreme high water of spring tides and is c.qxJSed to regular alternating flooding and draining by tides, FaCtors that determine physical chaf3cr~risti(S of beaches include sediment grain size, wavc action. Stonn5o tides, and tidal
r:mge. beaqa inclinatio~,
amount of ground\-mter input. and human activities. Environmental conditions on sandy beaches present a relentless challenge for the inhabitants, To survive in such a habitat, a species must withstand s~ng wave and current.action, tidal rise and fuJi. shifting sands. predation, and a wide variations in salinity and temperature. Given such high st::rt..--s.s con di~ons, penllanent residents on the beach are specialized and highly adapted,
Animals able to survive these conditions may be divided into three groups-: surfuce dwellers. burrowing species, and tiny animals that live among the grains of beach sand. Surface dwellers are primariJy pred:ltors and are limited
to a few groups, such as birds, that arc adapted to the unyielding conditions ". on an exposed beach. Burrowing is an effective coping mechanism for handling the rigors of the beach environment, A common beach resident is the abundant, hardy, and highly mobile ghOSt crab,
Inhabitants that live among !.he ,iand grains are primarily detrirus feeders and include copcpods, nema'todes and f1atwonns, though cvery major category of animals (except sponges) is represented: These animals do not dig through the sand. Instead they travel through the water in the spaces between thc grains, This diverse assemblage of anjmals can be casily extracted from their sand haoitms by .scooping some sand into a common kitchen strainer and pouring seawater over the rpp,\washing away the sand grains and exposing the small animals.
The mte,-stitia! beach habitat ir e~'posed to ,.egll!a,. "!temating flooding and drammg by the tides.
GHOS';' Ctt ....
(Ocypode qluulmtn) Visit the beach between dusk and d:lwn and you will . epcounter the ghost crab, scurry~ng towards the surf or the security of its burrow nearby, These crabs havc earncd thcirnamc for twO their sandcolored c.'<oskeletons and their nocrurnal tendencies.
both of which allow them to effectively disappear when necessary. Like othcr crabs, their large sulkcd eyes ensure excellent \'ision in all directions. The eyes aid in the search fo"l', food which is eventually located by taste or smell.
Their light weight exoskeletons and eight ;Iender walking legs . provide the
nimbleness that consistendy evades predators. They grow 10-15 em (4-6 inches) in width, including their jointed legs and look like no other crabs on the coast. Ghost crabs are terrestrial, preferring w hide in their e.'nensive burrows during the day and emerge at night. Voracious predators and occasional cannibals, these crabs are ~own to
up, dig crush with their
claws and ingest coquina clams, IllQle crabs, and even hatchlingsca turtles. lnough they are one of the top carnivores on the beach, ghost cmbs are not above SC3venging on anything fr0111 sea umle cgf,>S to dead tish and will even dig a burrow ncar or under the food.
Ghost crab burrows protect thel~ fr0111 unusually high tides, the harsh mys of the sun, severe ~inds, and predators. Near lnid-day they plug the entrances of their holes with damp sand and exca \'lite themseh'es once the
air and sand tcmperanm~s cool; After an extended Stay in their cool burrows, ghost cmbs head for the swash zone. Although they live on the dry sandy beach and breath air with their gills, they must wet their gills periodically for them to function. Tuns of line exoskeletal hair ate used to wick ground water up to moisten their gills. GiUs also aid in the regulation of excess salt in the animals body. Rarely will the crabs enter the water, though they can survi\c for a shon time if submerged forcibly. Smaller individuals dig their short \"Crtical burrows deeper and closer to the water than older, larger crabs, to ensure a shorter journey to the water's edge. The burrows of older crabs arc often dug at a 45 angle, often with branches for food storage or in Ushaped tubes up to four
feet deep. Burrow excava-
tion may take minutes to hours, and they oftcn have a second elltr.IIlCC.
H
He CR,I\II
(Limulll! polyp/mJllls)
The common name of this
animal ismislcading.ltjs
more closely related to
spiders than crabs. The
jointcd Icgs givc it
away as an
Arthropod,
but the
horseshoe "crab" is in the
subphylum Chelicerata,
not Crustacea like the true
crabs. llorseshoe crabs have
inhabited the earth since
before tile age of the dinosaurs. Ance~try of the crabs we see today can be traced back 500 million years to the middle of the Cambrian Period. Four species of horseshoe crabs exist today, but only . Li1lJ1IIus PfJlYP)Jt1JlIIS is found along the North American coastline.
HorSeshoe crabs move to deeper water offshore in the winter and migrate into ttae wanning coastal waters each spring. The horseshoe crab arrives oQ. the beach to spawn during a new or full moon high" tide. Males patrol the beach at the water's edge waiting for a female to emerge frOI!! the surf. The large fematesare pursued by a number.of males, all smaller than she is, and one of the males eventually cliinbs on her b::ack and holds on with speci::ally adapted claspers (modified first claws). The couple remains together as the female crawls up the beach to the high tide line. Once there, she digs a shallow nest and deposits 200 to 300 small grecni~h eggs. Immediately after the egb'S arc deposited the male rcleases his milt, or sperm, over them, and the p:lir, still joined, returns to the ocean. The pair may remain joined and return to spawn again on ::another high tide.
Turn the horseshoe crab over and you see five pairs of walking legs. At
the base of the legs is the bristled, outer surface of the mouth. The bristles are used to collect and grind up the crab's prey. The horseshoe crab alwavs moves while it eats,' because the mouth only moves when the legs are moving. The b001.: gills are white and flattened, and are located behind the mouth and legs. They a~e called book gills because they overlap resembling p::ages in a book. As all gills, they' enable the animal to extract oxygen from the water, This species of crab is so hardy that it can survive for a year' out of the wate{ if the gills are kept damp.
Pushing through the sand like a bulldozer, the horseshoe crab sColvenges on mollusks, worms, al'g;le, ;lnd other,organisms. Very few animals prey upon the horseshoe crab; certain species of sea turtles, such as the loggerhead, relish a meal of these crabs, and they may become a me:rl for a few species of sharks. Shore birds feast on the eggs of the horseshoe crab.
...DRAWINGS: "
RACCOON
(lJ,peyOllI0101) Raccoons roam freely t~rough the maritime forests, salt marshes, barrier island beach and dunes. Each of these habit::lts is a larder for the those infamous masked bandits. This inquisiti\'e animal has dexterous hands much Like those of a person (wi\:hout. our opposable thumb), which allows these omnivores to capture, SC3\"enge, and raid a remarkable variety of foodstuffs. Raccoo~s prey on fish, clams, crabs, crayfish, inSects, worms, small rodents, frogs, arid plants such as wild grapes, acorns, shoots, and palI~etto berries. However, it is their role as egg predators that causes biologists to pay attention to these opportunistic nest raiders. In Georgia marshes, raccoons are a significant predator of ground nesting birds' eggs and hatchlings. On the barrier island beaches, raccoons ptunder sea turtle nests under the : cover of darkness-throughout the summer months. They dig into the nesting cavity and consume some of the 120 or so eggs, then leaye the relnaining eggs vulnerable to other predators and exposure.
Raccool1s are easily identified by their black mask. ringed-t::lil, and gray to reddish-brown fur. They are about 60 to 95 cm (24 to 38 inches) in Ienbrth and weigh an
'I l1V$=rage of 5 to 15 kgs (II
to 33 pounds). Look for
raccoon footprints in soft
soils or muds around
I
marshes, tidal creeks,
ponds, or island sloughs.
The hindprints are g. to II
em (3.25 to 4.25 inches)
I I . long and resemble a
human I':!.. . . . . .
footprint
....1th extra
long
toes,
Foreprints
are much
shorter,
about 7.5 on
long and 7.5 em
wide (3 by 3 inches),
with all five t0C5: and claws
showing.
In December or January, male rac<:oons ~"'ch for
mates. Females arc quite
particular in ac<:epting
mates, but once a partner
is chosen, they spend
about a week together
before the male dep:irts.
Females prepare the den
site, typically a leaf-lined
tree cavity~ Gestation is
twO months long and the
cubs arc born in M.arch or
April. Liners consist of
fOLir or five cnbs who
measure 10 cm (4 inches)
at hirth. Almost seven
_ weeks pllSS before the cubs
:lrc ready to venture out of
the den, but by the time
the cubs arc three months
old they arc following
their mother on nightly
forays for food. By autumn,
the young raccoons are on
their own.
G"AY'S RICI:I'" NATIONAL: "'A"IHI: SAN(:'I'"IolA"Y
Considered to be one of
the largest near-shore,live
bottom reef on the South
Atlantic U.S. coast, Gray's
Reef National Marine
Sancruary is located 17
nautical miles east of Sapelo
Island, under 20 to 23 meters
~iIIlI \ \U
(60 to 70 feet) of water. Fonned from marine
sediments deposited during the Pliocene Epoch, Gray's Reef today is one of the
_, ~ larl:,rcst inner-shdflive bortom reef off the coasts of
the sou'theastem United
SCltes. The reef fOnlled
when sand, shell, mud, and.
clay, depositt;d oct\}'cen 5
and 2 million years ago,
,-, \ consolidated into lime-
~~ stone and sandstone rock. as a result of several cycles . of cmcrgence and subOlcr-
O gence as sea level f1uctuat-
.
ed during the subsequent..
.~~''
,
Pleistocene (Ice Age) Epoch. As glaciers advanced across North America, sea level dcopp,d " much" 100 meters (300 feet), advancing the Georgia cpastline east of its present location, and exposing much of the
formally submerged conti~
nental shelf, including the ~
area that is now Gray's Reef.
Coastal rivers and rainfall provided freshwater that wquld leach minerals and metals from the hardened sedimcnts. This leaching of material caused the Iimcstone and sandstone rock to become soft and porous, resembling poorly set concrete. As the glaciers retreated 18,000 years ago, the sea level began to rise, and the coastline migrated westward back across the continental shelf. Centuries of wave action eroded the consqlidated sediments fonning the ridges, slopes, and troughs present at the reef today.
Rock outcroppings rise up to 2'meters (6 feet) above the ocean Aoor con,tributing to the spectrum of geologic relief within the reef area. These features provide the physical foundations necessary to support a remarbble variety of marine organisms. Micro habitats on a reef ridge, for example, will suppOrt different organisms, in kind and percent of cover, than are found in slope or: sandy trough areas. The rock is soft enough for burrowing . and excaVating marine organisms, yet hard enough for algae (seaweeds), sponges, hard corals; bt()rgonians, bryozoans, and other marine org:misms to attach themselves: This hard substrate occurs infrequentlyoffshore from Cape. .Hatteras, North Carolina to Cape Canaver.ll, Florida, an area referred to as the South Atlantic Bight.
Tnll)' all oasis 111 a u:~te1J dese1"t, Cray's Reef mppo-rrs. t'irtua/~y
~'t'1)' group of
animalsfrom spunges to
vertebrates.
O"'HO.' R ....
Most of the continental
I shelf of the South Atlantic
/".~......aII'lII::ll'ilI:\l~",Bight is an ocean floor
composed of loose
~ -. ---..;:
'
sediments of sand,
. silt and mud. Few
-~.: 9rganisms can
~ ~. ~ . . . '~
,
... ",' ~ .... ~ .
live on such a shifting bottom,
WhichcomPf.is,es95 to 97% of the contmental shelf off Georgla. Largf
": ::" , conununitics of botrom-
n';lI'm U'lItO' frmpn'atures /11 fbI! mmmer mppo1't a v:idr 1."llriery offish at
Gray:rReej."
dwelling species are found only where a hard lxmom protrudes above the sand and provides a solid SUf4 face upon which plants and
animals can grow. -lhJlyan oasis in a watery
desert, Gray's Reef supports
virtually every phylum frOIll
Porifcr:a (sponges) through
010rdates (animals with a
notochord, includes
venebrates). Marine fishes,
reptiles, birds, and m3nuna!s
represent fou,r of the nve
vertebrato classes. that are \
found at the sanctuary,
along with approximately 70
species of marine plants frQm
four major plant divisions.
In rUCob'llition of the
unique character and criti-
cal habitat area \.vithin
Gray's Reef, it was desig-
nated a National Marine
Sanctuary in 1981. It.is one
of 12 National Marine
Sanctuaries established and
maintained by the National
Oceanic and Aonospheric
Administration (NOAA)
(U.S. Department of
Commerce) for steward-
ship of significant natural
and historical resources.
Gray's ReeLis located 17 nauticalmi1es (22.5 miles) east ~f Sapelo Island, GA. A position on the'relatively shallow inner continental shelf contributes to a greater fluctuation and n19re rapid changes in temperamres than an...area in the open ocean. Wat~r tcmperatures in the Sanctuary range from a summeihigh of 28C (82F) and drop to 14C, (SrF) in winter. Although it is not uncommon for certain species to be found seasonally, ,this range of water temperatures makes it possible for both temper~ ate and tropical species to thrive in the Sanctuary.
Seasonal (Jucruations of organisms are also influ~ enced by changes in salinity, due to freshwater input from coastal rivers and varying weather conditions. Populations of plants and animals at Gray's Reef have been described as transitional, due to the wid~ range of abiotic or physical parameters. Warm water temperamres in summer attract tropical fishes such as angels, butterfly fish, c'!rdinals, and damsels which are transponed to the reef in Gulf Stream eddies. These beautiful exotics join the familiar year-round residents: black sea bass, gag grouper, snapper, sheephead, spade fish, porgy, cobia, and barracuda.
Among the ledges and overhangs of the reef, sea turtles (Ioggcrhead, green, leathe:rback., and Kemp's.
s Gray Rufi.us desigrllJted
a ;'\./at/olla/ .\farine
Sanctuary /111981 .
DRAWINGS:
ridley) forage for food or simply rest; these endangered and threatened reptiles find refuge at the reef.
Sancruaty waters also serve as calvinggmunds for the highly endangered Northern right wha1es. The cows migrate into these waters in early winter
then. to give binh to a single caI
before returning to feedi.ng grounds off New England in the spring. On the surf:.ice waters above the reef, sever.l! specieS of sea birds, such as terns, gannets, and perrels, come to.rest and feed during their seasonal migrations.
The calcareous sandstone ledges of Gray's Reef provide finn surfaces for plants and animals to attach themselves. These ledges are .co\ered with colorful sponges, mnicates, hard and soft corals, sea anemones, and hydroids. The attached organisms provide fuod and shelter for many of e more mobile residents of the reef such as sea S1:3rs, brittle S1:3rs, sea cucumbers, urchins, crabs, IOQsters, squid, and snails. Other invertebrates include cannonball jellies, and COJl1b jellies which drift with the currents abov~ the reef.
LOGGII:RHII:AO 511:A
TURTLII:
(Cormo (oretta) , Sea turtles have been on the earth since the time of the dinosaurs, more than 135 million years ago. Five species of sea turtles regularly spend part of their
lives in the U.S. coastal
waters of the Atlantic Ocean and Gulf of Mexico: loggerhead, Kemp's ridley, green, leatherb:lck and h:lwksbill. Loggerheads are the most conuoon SC:l turtle on Georgia's coast.
These anciem rep-
tiles are remarkably ~~~'.,.~~~!!!I!!~1W
adapted to life in the ocean with flippers instead of legs and , body shaped for efficient movement through the water. A large, heavy body with a hard shell provides protec tion for adult turtles from mOSt predators (sharks {Ire an exception). Loggerheads nonnally weigh 7~ to 140 kg (170 to 315 pounds) and attain a length of80 to 125 em (31 to 49 inches), measured in a straight line from the front to the back of the shell edge. Loggcrheads are covered with a hard, bony shell formed by the fusion of t~e vertebra and ribs which is covered by scales, or scutes. The upper shell is called a. carapace; die lower shell a plastron. Adult logger~ heads have a slightly elonb"3ted heart-shaped carapace, wider at th~ front and ":lrrowing toward the rear. The cara-
p:lce is reddish-brown, often covered with algae, barnacles and other attached organisms.
Sea 'turtles have front
and rear pairs of paddle-like " flippers equipped with one
or twO claws. Unlike
their land rdatives, sea rurtlcs cannot retract their extremities into their shells. Aptly named for their broad, massive heads, these turtles have sharp beak-like jaws with . muscles particul~rly well-adapted for crushing hard-shelled prey. Primarily a carnivore, they forage on mollusks and crustaceans such as horseshoe crabs, true crabs, and wbelks. They are mostly bottom
I feeders but will consume sea jellies at the surface .. or in mid-water.
Completely ad::llpted to the marine environment, sea nudes live . without access to fresh water. Th~y ingest large all10lmts of ocean water while feeding, excreting excess salts through tear duets. Located in the corner of the eye, these. lacrymal glands coordinate with the kidneys to regulate the level of salts so the turtle remains hydrat~d. Like all reptiles, sea turtles are ectothermie (cold-blooded); their i11lernal temperature is within a few degrees of the external medium (leatberbacks.are an exception). Ocean temperatures ofT
Gt;orgia shift seaSOl1ally and sea turtles respond by migcating to \\;armer 'areas in the winter or over-winter'ing among the ledges of hardbonom reefs.
r"
\I.J
FIIlLD TRIP RlleO ...... Il.HD ... TION
~ f""""\aPlanning is critical for safe, educational, and
~ r--,
enjoyable fi'eld trip. All field trips require COIllman sense and personal responsibility. It is
always good planning to
~ be current on rour firstaid certification. Be sure to consider aU 'special needs of your trip mem-
,., \ bers. The following are
~ "" .......
general guidelines for
your trip planning. The list is not intended to be
' - ~ exhaustive or cover e\'et:}'
, , " " emergency.
\""I..J 1 Plan your trip in
advo1lce. Write a trip
i~ := .. itinerary and_le<lve one copy in your vehicle and one with
a friend or relative
~.
before you dcpan.. Include your route, approximate renJTIl time, and cont.1.ct names and phone
""'d 'aj
numbcI'S"in case of an emergency.
2 WaIn: Carry plenty of fresh water. Do not dri~ from ponds,
~
rivers, streams, or any other outdoor source without proper purification.
3 Fmr-aid supplia. Carry a first-aid kit containing assorted bandages, tape, moleskin, disinfectant, and personal medicines.
4 51111 protectiun. Carry a hat, sunscreen, lip protection, and sunglasses. Consider a long-sle~vcd shirt and long pants even in the warmer months to protect from sun exposure.
5 Food. Bring enough food for the duration of the Dip, plus extra for the uneXpected. Dried fruits and nuts are lightweight and high in energy.
6 II/sects al/d arachnids. Bees, wasps, and yellow. jacket stings range from loc.!l irritation to life threatening anaphylactic shock. Be aware of any respiratory distress or' wheezing. Seek medical , p'eaunent immediately. Two tick-borne diseases are known in Georgia: Lyme disease and Rocky Mountain spotted fever. Be sure to check your body for
- ticks after each day outdoors. Removing ticks within 8-10 hours is important. Use tweezers to grasp the tick as close [Q your skin as possiblc and gently pull the tick away. Be sure to removc the entire tick, including its head and mouthpans. In ilbout half of the cases of Lyme disease a red bulls-eye appears. If a
round, red rash occurs at the site of the bite or if you experic:;nce flu-liJ(e ~ptoms, report to your doctor. It is advisable to wear white or light colored clothing in areas where ticks are prevalent.
Red bugs or duggers, mosquitoes, gnats or midges, and biting flies em make a trip into the outdoors less than pleasant. Carry insect repeUent. Some brands of insecticides are more effective in repelling ticks, chiggers, and insects than others; read the labels before you choose your poison. DEET is effective for many kinds of pests and is the active ingredient in many insect repel~ lents. Do not apply insect rcpellent above
the eyes as sweat can cause it to DickIe downward and cause 'severe
eye injury. Avoid aerosol cans if possible. Solid .
sticks are just as effective and safer to apply. H you must sprny insecticide, ~ove away' from other people before you do so. Remember, insCt:ticides are designed to killliving things, so wash your hands thoroughly before you (,'3t, rub your eyes, handle animals, or dress a wound. If you desire to be bug-free without insecticides, consider wearing 3 mesh head-
net, long-sleeves, 3Jld tuck your pants into your socks.
Do not feed or blil/die veild animall". Feeding 71'i/dlife encoll1'oges tbn" to app"ol~fb fo,. food, Tbe best 71'lIy to fIll'e for 71'ildlife is to protect tbei,. habltllt,
NOTES:
7 Gmeral cautions. Be able to identify poison ivy and avoid contact with both leaves and stems. Also, be aware of~ Diomondbod< rattlesnakes and other poisonous snakes are residents of this eeo-SYStem. Be cautious stepping over logs or reaching into cavities. If you are concerned
::~~~~~s~~~;~~ It
approximately 35,000 people are killed in auto :H.:eidents each ycar in thc US alone, but less than 10 people die from snake bites annually in all of North Ameri6. Most bites occur when pcople try to carch or'hold poisonous snakes. If vou are binen, re~ember what the snake looks like and get medical attention immediately.
II Wi/d/ift. 00 not feed or handle wild animals. Feeding wildlife cncourages thclll to approach humans for food. The best way to care for wildlife is to pro~ teet their habitat.
9 Be pre:pared. Consider carrying the following; pocket knife, compass, rainwear, extra jacket, notebook and pencil, field guides, magnifying glass, and binoculars.
In 1912, Detroit auto-motive engineer
l"
Ho~ard E. Coffin pur-
chased Sapelo and estab-
lished agricultural oper-
ations, a seafood busi-
ness, and an ambitious
construction program,
iric~uding restor- ation
of the mansion in 1925.
Tobacco millionaire
Richard J. Reynolds Jr.
owned Sap~lo from
1934 until his death in
1964. Reynolds donated
land ,!nd bpildings to the
University of Georgia
for the creation ofa
marine research facility.
BEACH NOURISHMENT
'artificial beach' nourisllment is a method of beach creation in which large amounts of dredged sand are placed on eroding beaches.
PARK I N,,"ORMA.TION
pertaining to the bottom
Ptll'k floll!)"
of a body of water.
Guided tours:
BENTHO~ the community of organ-
September - May:
isms living on or in the
Wed. 8:30 AM - 12:30 PM
bottom of a lxx:Iy of water.
Sat. 9:00 AM - 1:00 PM
,
An additional tour is
B!OGENIC describes changes in the
offered June - August:
environment> resulting
Fri. 8:30 AM - 12:30 PM- -
from the aqivities of liv-
For reservations,call
ing organisms.
(912) 437-3224.
.'lddrr.'iJ Sapelo Island National EstuatiJleRe;earch .Reserve, P. O. Box 15
BRACKISH WATER water with a salt content br;:tWcen 10 and 30 parts per thousand.
Sapelo Island, GA 31327
Pllrk 7th'phonc 1lI/(1 '-CJe',.
PlltiOl1J }or piolleer t'tIlJIping (912) 485-~251
~
ReJer..'luiOflJ
(800) 864-7275
fj,rbSirt
www.gastateparks.org
CLlfIIAX FOREST
a relativ~ly stable stage reached in some ecologiea.l successions ~sequence).
COMMUNITY a group of interacting ang interdependent species in a,restrictedar(.-"3.
the washout or settling
IN CASE 0'
of material from the
EMll:IltGI:NCY
atlllosphere to the ground
Contact the island inan-
or to surface waters.
ager for arrangements to
,..
evacuate the island.
DESICCATE t~ dry out, dehydrate.
DETRITUS fine particulate organic matter in some stage of decomposition.
a biological community and its nonliving environme~t.
ESTUARY the region of fluctuating salinities where a river meet'S the sea.
FILTER FEEDER
an animal that feeds by'con~ centrating suspended organic particles by filtration through sieve-like organs.
GEOMORPHOLOGY
geo-Iand and morphology!;he study of shape or form. The study of the nature . and origin of t.he land features of the canh.
lower tides that occur when the sun and moon Partially cancel each others gravitational pull on the eanh.
OSMOREGULATION
rcbrulation of the water concentration of body fluids in such a manner as to keep them relatively constam despite changes in the extern-al medium.
salt marsheS" are found in protected coastlines in th..e middle to high latitudes. Plants and animalsjn these are~lS are 3dapted to peri- odic flooding and extremes in temperature.
higher tides that occur when the gravitational pull of the sun and moon combine.
m3rsh grass or other vegetation cast up by tides or waves and Stranded on the shore.
Sarah Mitdlell
Skipping Stones Design
Y.J.Henry Hans Neuhauser Reed 80Ime Buddy SullMn Laura Francis NancyO'Donnell Anne Lindsay-Fric~
Georgi'a Dept. of Natural Resources, Wildlife Resources Division & State Parks and Historic Sires Division
.Gray's Reef National Marine Sanctuary, and the Marine Sanctuary Division,NOAA
Sustainable Seas Expeditions
U.S. Fish aJ;ld Wildlife