The Ecology of the Seagrasses of South Florida - USGS National ...

leaves oF seagrasses hav2 been shown is also the key tcl restoring dananed or
to Fig nitrogen, thus adding to the denuded syster~s.
r~utrrient. pool of the region. In addjtjonx
5cagrassrs have beer1 shown to
pick ilp qut.ricnts from the sedirilents, 4.3 SPECIES Sl+'CCESSIOpI
transporting their1 throuqh th2 plant
and relcaslng the nutrients into the Thro~rqhout the sout? Florida rcoion,
water cirluinri through the leaves, thus and nost of the Gulf of Eexico and Caribdcthng
as a nutrient puvp fror? the bean, the species of plants that particiseciis?er~l
pate in the successional se~ucnce of seagrasses
are remarkably few because thtirr
are so few marine plants that can colonize
4.2 SIICCESSICIEJ ANE! ECOSYSTEM OEVELOPMENT unconsol ida tcd sedirnents. In addition to
the seaqrasses, one other group, the rhi-
In eonventlonal usage, succession zophytic green algae, has this capability.
r-csfers to the orderly development of a These algae, however, have only linited
scrics of c~~n.j~jni ties, or sera1 stages, rhi zoidal development and never affect an
which rc%ulb; Jn a clitaax stage that is in area greater than a few centimeter5 from
eqrrli 1 ltlriur: with the prevail tny environ- their haw.
rwrt tn f cond i t Jtrns . f rl wre con tei?porarSy
u%i;nge, trowever, nuccesslion is more brtladl y The rlost cor71;ron illustration of sucxtsed
to i*oelan the succession of ?;prcir;s, cession In scagrass systc~s is the rccolo-
$trudture, and functfons within an ecosys- nization fallowing a "blowout." This loc-
Leu.:, Odurtr (19654) stated contemporary al i zcd di sturhance occurs in seagrass heds
concept 4% follows :
througlrout Florida and the Caribbean where
there is sufficient current movement in a
1) Suecessiof~ $5 an orderly process domillant direction (Figure 9). Usually a
of cry$t~t~*rtrn.i t-y devclogment; thdt in- dl srugtfon, such as a rlajor stortn, overvrrlvcr
changes in species Structure grazing caused by an outbreak of urchins,
and casr:nrvun!tt;y prcrccsscs with tittle; it or a trldjor rjpping of the beds caused by
$5 rcaronirhle, directtonal, and drdgyirlg a large anchor, is required to
truere tore [nredicldlrl e,
initiate th~? blo~out, Once started, the
holes are enlarged by the strong water
(2) Sucecss?lon results fro111 plodiff- flow which causes erosion on the dovin cur-
(:dtSof\ of tile ~3haysicill envir~~~q~ylt b~ rent side. Slowly a crescentic shape a
the corat8urri ti; that is, sajccession .is Few nleters bride to tens of peters wide is
cots!tioity+controI ICE^ CV~II th~tugit the Forrned. A saapl c cross section in Figure
b~hy..;icxnf cnvirari~rienl deterinitles the 10 shows a mature turt? e grass corlnuni ty
~t~clttt%rn and the r01~ OF chan~p, and that has been d3srupted and is recoverin$.
t~rten sets lr";..rEts ds to haw far The region at the hasc of the erosion
dlzvcl ikpriaent cdri qn, scarp is highly agitated and contains
large chunks of consol idated sediment and
63) Ssar,ee!ssinrl cuf rriiitates irr a st*- occasional rhirorile frag~ents, CIi th inbll
cctlsystart in which ;rraxicturrt creasing distance from the face of the
I%~PJI\~SS
%or hfqh dnfonaiation c~ntcnt) scarp, turbulence decreases and sorne {?atedfld
~~:thfotir: ~WIIC~~D~) bct~~en or.gan- rial is deposited. The area has hecome
4 sF1s are ~r~ixintlsinftd per irr~it of colonizetl with rhizophytic algae; Hal imda
avilll ablx? etrerlry Flow,
and Penicillus are the most abundant, but
, -tihatea, -- Rhipocephalus and
Species ruccessfon has received by 1 lea are also comon. These algae
far tqe R0St atreririon as it is r-tusi pi-avid+ a certain a~ount f sedirqent-
~bviuus and easily mcasused, The study of binding capability as illustrated iq Figsracce%sion
af pt-acesses or functions is ure II, htrt they do nut stabilize the surjust:
ta@$jnnln?, however, Xt: nlay well 1 prove face of the sedirqents very well (Scoffin
fl(J5t i!?partant @venire for undey- 1970). A rslajor function of these a1 gae in
standing ecosysle;ln development. Defining the early successional stage is the con-
PPQCESS@S is OF much greater impor- tri bu tian of sedimentary particles (Hi 1 -
ta~c@ than raerc scietltific curiosfry. It liatns 1981)- The generalized pattern and
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