8/9/2019 Marine Biology Exam III Study Guide http://slidepdf.com/reader/full/marine-biology-exam-iii-study-guide 1/57 Exam III Notes Lecture 27: Rocky Intertidal Communities • Main Questions to be answered in this section: ! "hat are the main #hysical $actors in%uencin& community structure' 2! "hat are the main biolo&ical $actors in%uencin& community structure' (! )ow do #hysical and biolo&ical $actors interact to ex#lain s#ecial and tem#oral *ariation in community structure' + ,hysical $actors in%uencin& the community structure o$ rocky intertidal communities • "hat is the intertidal' o The intertidal is a narrow strip of habitat that lies between the highest high tides and the lowest low tides o Readily accessible to marine biolo&ists so it is the best understood o$ marine communities a+ -he e.ect o$ tides − "hat makes the rocky intertidal an intertidal' /re*iew o$ tides! o -ides are caused by the &ra*itational attraction between the Earth0 Moon0 and 1un o -idal cycles → diurnal / hi&h tide and low tide #er day!0 semidiurnal /2 hi&h tides and 2 low tides #er day!0 or semidiurnal mixed tide /2 hi&h tides o$ di.erent hei&hts and 2 low tides o$ di.erent hei&hts #er day! o Organisms alternately experience emersion and immersion in seawater − -he e.ect o$ the 1un on the tides o Neap Tides → the &ra*itational e.ects o$ the Moon and the 1un are at ri&ht an&les to each other o Spring Tides →the &ra*itational e.ects o$ the Moon and the 1un are coincidin& with each other − "hat are the challen&es o$ intertidal' o 3r&anisms alternately ex#erience emersion and immersion in seawater
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+ Desiccation stress: Intertidal or&anisms re&ularlyex#erience emersion0 and marine or&anisms tend to dryout when ex#osed to air
2+ Heat and salinity stress: Intertidal or&anismsex#erience &reater *ariation in tem#erature and salinity
than subtidal or&anisms(+ Restriction of feeding: Many intertidal or&anisms muststo# $eedin& when ex#osed to air0 which can ha*ene&ati*e 4tness conse5uences
b+ -he e.ect o$ wa*es
− "hat makes the rocky intertidal rocky'o Rocky shores usually occur on recently u#li$ted or
&eolo&ically youn& coasts6 ex+ -he west coast o$ the mericas is rocky
because its acti*e mar&in has been u#li$ted
o )awai8i and Iceland are rocky because la*a %ows arecreatin& new rocky shores
− Recall0 wa*es interact with the shore /re*iew!
o 9ee#water wa*es intermediate wa*es shallowwater wa*es
o s dee#water wa*es be&in to ;$eel< the bottom o$ theocean0 $riction increases /dee#water wa*es!
o Reduced s#eed and wa*elen&thcause increased wa*e hei&ht andstee#ness /intermediate wa*es!
o "hen wa*e a##roaches shallowwater and tends to break /shallowwater wa*es!
− Recall0 wa*es bend as they a##roachshore /re*iew!
o -he ener&y o$ wa*es re$racted o*er a shallowsubmer&ed rid&e is $ocused on the headland
o "a*es re$racted by shallow de#ths on each side o$ abay means less ener&y inside bay
! Chthamalus stellatus /dominates the u##ershore to mean hi&h tide!
2! Semibalanus balanoides /dominates the lowershore to mean low water!
o Connell selecti*ely remo*ed hy#othesi@ed com#etitorsand ca&ed areas to eliminate the e.ect o$ #redation
o st0 Connell demonstrated that the lar*ae o$ bothbarnacles s#ecies settle throu&hout the intertidal
o Connell trans#lanted Chthamalus downshore andBalanus u#shore0 and ca&ed areas to eliminate thee.ect o$ #redation
• Chthamalus trans#orted downshore wereo$ergrown and nderct by =alanus
• Balanus trans#orted u#shore died due to their#oor sur*i*al in the u##er intertidal
o Connell8s classic ex#eriments lead to the &eneral
conclusion that:• 'pper limit o$ an intertidal s#ecies is re&ulated
by #hysical $actors
• "ower limit o$ an intertidal s#ecies is re&ulatedby ecolo&ical $actors /ex+ Com#etition0 #redation!
o In this ex#eriment0 #hysical $actors set the u##er limiton the distribution o$ both s#ecies while com#etitionset the lower limit on the distribution o$ Chthamalus
o Most rocky shores ha*e a distinct #attern o$ tem#oralsuccession /species composition changes throghtime following distrbances!
Ex+ #atches o$ bare rock can be o#ened u# by
wa*e action0 dri$tin& lo&s0 or scourin& ice →
when a #atch o$ s#ace is cleared0 new or&anismso$ten mo*e into the #atch and &et re#laced byother or&anisms in se5uence
− Beneral causes o$ tem#oral successiono In the rocky intertidal0 the 4rst sta&e in succession is
o$ten a thin 4lm o$ bacteriao -y#ical ecolo&ical succession:
=are rock →→ =acteria →
→ 1eaweeds →→ =arnacles →
→Musselso -he 4nal sta&e in succession is called the climax
commnity
− ariation in ecolo&ical successiono -he #attern o$ ecolo&ical succession can *ary due to:
+ Relati*e abundance o$ bacterial &ra@ers likelim#ets and chitons
2+ Relati*e abundance o$ di.erent lar*ae at timeo$ disturbance
(+ Relati*e si@e o$ the #atch created by thedisturbance
− Recall0 intermediate disturbance hy#othesiso Intermediate disturbance hy#othesis su&&ests that the
number o$ s#ecies will be hi&her at intermediate0rather than hi&h or low0 le*els o$ disturbance
(+ Alternati$e Stable States
− ,atches exist in alternate stable states
o common obser*ation on rocky shores is thecoexistence and #ersistence o$ lar&e #atches withdi.erent dominant s#ecies0 e*en when all o$ the s#aceis occu#ied
o -he landsca#e may be #atterned by @onation andsuccession0 but also maintained in alternate stablestates0 which de#end on 4rst coloni@ers $ollowin&disturbance
Lecture 2D: Estuaries /Mud%ats0 Marshes0 and Man&ro*es!
• Main Questions to be answered in this section:! "hat are the main #hysical characteristics o$ estuaries'2! )ow do #lants and animals deal with *ariation in salinity'
(! "hat are the similarities and di.erences between salt marshesand man&ro*es'
+ ,hysical characteristics o$ estuaries
• "hat are estuaries'o *staries are semi+enclosed areas where
freshwater and saltwater meet and mixo -hey are a #lace where terrestrial and marine
ecosystems interacto -hey are amon& the marine en*ironments most a.ected
by humanso Estuaries are ty#ically inhabited by $ewer s#ecies than
rocky shores because o$ the ra#id en*ironmentalchan&es
o Estuaries are $ound alon& the shores o$ all the oceans
o Estuaries *ary &reatly in si@e0 but there a basic ty#es0de4ned based on their ori&ins
• "hat are the basic ty#es o$ estuaries',- !oastal plain estaries or drowned ri$er $alleys
Estuaries that $ormed when sea le*el rose with meltin&
ice at the end o$ the last ice a&e /D0FFF years a&o!.- /ar+bilt estaries
ccumulation o$ sediments alon& the coast builds u#sand bars and barrier islands G #artially enclosed sectiono$ coast
0- Tectonic estaries Estuaries that $ormed when the land sank0 or subsided0
as the result o$ mo*ements o$ the Earth8s crust1- 23ords
Estuaries that $ormed when retreatin& &laciers cut dee#
*alleys alon& the coast
alleys #artially submer&ed when sea le*els rose0 andri*ers %ow into them
• )ow does salinity *ary in estuaries'o -he de4nin& characteristic o$ estuaries is the mixin& o$
$resh and salt water in a #artially enclosed section o$the coast
o 1tenohaline s#ecies /many s#ecies! =rackish waters#ecies /$ew s#ecies!
o Most marine or&anisms ha*e internal salt concentrationhi&her than $reshwater and take on water by osmosis in
estuaries! Osmoconformers maintain osmotic balance by
allowin& body %uids to chan&e with salinity o$water /ex+ molluscs0 worms!
2! Osmoreglators kee# salt concentration o$ body%uids more or less constant *ia acti*e trans#ort/ex+ 4sh0 crabs!
o Estuarine #lants are saltier than their surroundin& water
→water u#take occurs by osmosis /this is not the case$or #lants with roots in estuaries!
o 1ome acti*ely absorb salt and concentrate su&ars tomatch outside concentrations and #re*ent water loss
+ Estuarine Communities
• -wo maJor estuarine communitieso Estuaries in tem#erate and subarctic re&ions are o$ten
bordered by &rassy areas that are #artially %ooded athi&h tide and extend inland $rom mud%ats: saltmarshes
o 5angro$e forests tend to re#lace salt marshes alon&similar coasts in tro#ical re&ions
a+ 1alt Marshes
− In the Northern hemis#here0 salt marshes are more commonon the le$t side o$ estuaries than the ri&ht side becauseerosi*e $orces are less on the #assi*e mar&in o$ continent /thele$t side o$ estuaries!
− 1alt marshes start on muddy bottoms but the mud &ets heldtoðer by the rhi)ome system o$ the #lants
o Rhi@omes take u# nutrients and allow the #lants toextend laterally
o s rhi@omes and shoots extend laterally0 they $acilitatesedimentation
− ertical Konationo -here is *ertical @onation across salt mashes /similar to
o -he location o$ a &i*en @one is related to its hei&htrelati*e to the tides0 #hysiolo&ical ada#tations0 andinters#eci4c com#etition
o -he border between @ones can be 5uite shar# and at
#redictable tidal hei&htso Ex#eriment conducted by Mark =ertness
Conclusion:
+ "ower limit o$ salt marsh #lants isre&ulated by #hysical $actors
2+ 'pper limit o$ salt marsh #lants isre&ulated by ecolo&ical $actors /ex+com#etition!
o -o combine theories o$ =ertness0 Connell0 and ,aine: Lower limit o$ or&anisms o$ terrestrial ori&in is
re&ulated by #hysical#hysiolo&ical interactionswhile the u##er limit is re&ulate by ecolo&icalinteractions
A##er limit o$ or&anisms o$ marine ori&in isre&ulated by #hysical#hysiolo&ical interactionswhile their lower limit is re&ulated by ecolo&icalinteractions
− lternate stable stateso 5arsh wrac% is dead marsh &rass that $orms layers on
to# o$ water or marsh sur$aces → smothers the &rassand decom#oses to create a bare )one
o 3nce an area is bare0 stron& sunli&ht causese*a#oration0 which results in a layer o$ salt to de*elo#on the sur$ace
o -he salty layer #re*ents seed &ermination→ the bare#atch is sel$sustainin& as an alternate stable state
b+ Man&ro*es
− Man&ro*e $orests are the tro#ic e5ui*alent o$ salt marshes
− Man&ro*e $orests are $ormed by man&ro*es0 tro#ical and
subtro#ical trees and shrubs ada#ted to intertidal− Man&ro*es &row on #rotected coasts where muddy sediments
accumulate
− Re5uires $reshwater
− arious s#ecies o$ man&ro*e #lants ha*e di.erent tolerancesto immersion0 so there is distincti*e @onation
o Recall0 each indi*idual kel# is attached to the rockybottom by a hold$ast+
3ne or many stipes &row $rom the hold$ast and
fronds &row $rom the sti#es -he $ronds are sus#ended by &as 4lled
pnematocysts Indi*iduals can be massi*e0 &rowin& (Fm $rom
the bottom to the sur$ace
• ?ormation o$ a kel# $oresto Lar&e0 dense #atches o$ kel# are called %elp beds
/analo&ous to sea&rass beds!o 3nce the kel# ha*e &rown to $ull si@e0 and their $ronds
%oat on the sur$ace0 they are known as %elp forests
• ertical @onation in kel# $orestso Oel# $orests alon& the ,aci4c coast o$ North merica
exhibit distinct de#th @ones0 each made u# o$ s#eciesthat &row at a characteristic hei&ht abo*e the bottom
-his structure results $rom interaction o$
#hysical and biolo&ical $actors
o ?loatin& cano#y o$ &iant kel# de*elo#s only where wateris dee# enou&h to reduce wa*e action0 but shallowenou&h $or li&ht to reach the bottom0 #ermittin& &rowth$rom the hold$ast
o 3ther kel#s0 such as the bull and ?eatherboa0
contribute to the sur$ace cano#y $urther inshoreo -he elk kel# $orms a midwater cano#y in dee#er water
alon& the outer ed&e o$ the &iant kel#o 1maller kel#s ex#loit the understory
o 1horter al&ae /red al&ae! li*e under the two o*erlyin&layers
n atoll is a rin& o$ ree$ surroundin& a centralla&oon
-he *ast maJority o$ atolls occur in the Indo"est
,aci4c re&ions
n atoll can be thou&ht o$ as a circular barrier ree$:outerree$ and innerree$ slo#e o$ atolls can beanalo&ous to the $oreree$ and backree$ slo#e o$barrier ree$s
tolls can be (Fkm acrosso -he water may be hundreds0 or thousands
o$ meter dee# Just o. the outerree$
tolls are $ormed by ree$ &rowth on a subsidin&
island
a= n atoll be&ins as a $rin&in& ree$ around a*olcanic island
− -he two main ways in which corals com#ete $ors#ace are by o$ergrowing and directlyattac%ing their neighbors
− Benerally0 corals outcom#ete seaweeds
• Nutrient limitation and &ra@in& kee#s
seaweeds in check)owe*er0 i$ nutrient le*els increase /due to#ollution! or i$ &ra@ers are remo*ed /due too*er4shin&!0 then seaweeds can outcom#etecoral
.= Predation
− ,redation and &ra@in& are im#ortant in structurin&coral ree$ communities
− *ariety o$ #redators are s#ecialists on corals
− Benerally0 crowno$thorns sea stars0 occur in lowabundances →)owe*er0 there are sometimesoutbreaks or #la&ues o$ crowno$thorn sea stars
• -hese sea stars can decimate a coral ree$0consumin& e*ery coral in its #ath
− 3utbreaks o$ sea stars can occur in wet years→ there is more nutrient run o.0 and hi&herrecruitment o$ sea stars
− 3utbreaks o$ sea stars can occur due to o*er4shin&→ reduces #redation on youn& sea stars0
allowin& more o$ them to sur*i*e to adulthood
0= 5talism
− Mutualism enhances the &rowth o$ both#o#ulations0 makin& them $or resistant toextinction
− Note that &ases ex#andScontract as the or&anismmo*es u# and down0 in%uencin& buoyancy but swimbladders can only be adJusted slowly Many 4shes that chan&e de#th ra#idly ha*e
ado#ted the li#id solution rather than the &as
solution
Swimming the #oaters-
− mon& the e#i#ela&ic #lankton are hi&hly s#eciali@ed&rou# o$ or&anisms that %oat at the sur$ace o$ theocean /ex+ ,ortu&uese mano$war!
• *oidin& #redatorso In the e#i#ela&ic0 there is #lenty o$ li&ht and there are N3
structures to hide behindo ,redators are numerous and they ha*e wellde*elo#ed sense
or&anso Natral selection will ha$e fa$ored prey that ha$e a
lower li%elihood of being eaten ( basic strate&ies ha*e e*ol*ed:
o 1ome #arts o$ the e#i#ela&ic rank amon& the most #roducti*eecosystems on Earth
Recall0 #rimary #roducti*ity is limited by li&ht and
nutrients: "hat causes this #attern o$ #rimary#roducti*ity
Recall nutrients are always sinkin& out o$ the e#i#ela&ic
and there must be u#wellin&So*erturn to brin& nutrientsback to the #hotic @one /Season pwellingCo$ertrn6coastal pwelling6 e@atorial pwelling!
Lecture ((: -he 9ee# 1ea
• Main Questions to be answered in this section:! )ow do li&ht0 tem#erature0 and #ressure *ary in the dee# sea'2! "hat is the &eneral distribution o$ biodi*ersity across the
maJority o$ the dee# sea'
(! "hat creates islands o$ hi&h biodi*ersity in the dee# sea'
+ ,hysical en*ironment
• )ow do we de4ne the ;dee# sea<'
o *pipelagic: #hotic @one0 li&ht suVcient $or #hotosynthesis /F2FFm!
o 5esopelagic: dim li&ht0 but not enou&h $or #hotosynthesis/2FFFFFm!
o Deep sea: no light /FFF m!
• ,hysical en*ironment o$ the dee# seao 9ee# sea habitats ha*e no li&ht at all /#er#etually dark waters
below meso#ela&ic!o ,ressure increases with de#th at a rate o$ atm #er Fm de#th
o -em#erature is low /Just abo*e FC! -em#erature is low0 but relati*ely stable
o 1alinity is also relati*ely stable across s#ace and time
• Main Questions to be answered in this section:! "hat makes $or a &ood in*ader' )ow ha*e humans $acilitated
in*asion' "hat actions can be taken to reduce in*asion
$re5uency'2! "hat are maJor #ollutants and their e.ect' "hat actions can
indi*iduals take to reduce #ollution'(! "hat are maJor causes o$ habitat destruction' "hat actions
can indi*iduals make to reduce habitat destruction'
+ In*asi*e 1#ecies
• "hat is an in*asi*e s#ecies'o -echnically0 all s#ecies ori&inated at some #oint in history and
all s#ecies ha*e s#read naturally $ollowin& their ori&ino 7n$asi$e species are introdced species that negati$ely
a4ect the habitats they in$ade ecologically oreconomically
Ex+ -he Lion4sh is a naturally occurrin& #redator in the
Indo,aci4c re&ion and was introduced to ?lorida →Lion4sh are *oracious #redators and com#etitors0chan&in& the community structure o$ Caribbean ree$sand ham#erin& conser*ation e.orts
• "hat makes a &ood in*ader'o 7n$asi$e species often originate in regions with similar
abiotic conditions -his enables the in*aders to sur*i*e while their
#o#ulation numbers are still low
o 7n$asi$e species often achie$e large body si)es and high
poplation densities Esca#e $rom the e.ect o$ natural enemies /#redators0
#arasites0 com#etitors! is a $re5uent ex#lanation6 -orchin et al+ com#ared #arasites o$ in*asi*e
s#ecies in their nati*e and introduced ran&es6 -he number o$ #arasites $ound in nati*e
#o#ulations was twice that $ound in introduced#o#ulations
• "hat makes communities #rone to in*asion'o -heory #redicts that systems that are more di$erse should be
• Main Questions to be answered in this section:! "hat is the *alue o$ biodi*ersity in economic and
medical terms'
+ alue o$ biodi*ersity
• "hat is biodi*ersity
o =iolo&ical di*ersity /biodi*ersity! is the *ariety o$ li$e on earth Gits &enes0 s#ecies0 #o#ulations0 and ecosystems
• W MaJor threats to marine biodi*ersity! In*asi*e s#ecies2! ,ollution(! )abitat destruction! 3*erex#loitationH! Blobal chan&eW! #athy and the tra&edy o$ the commons
• "hat incenti*e is there to act'o Ecosystem 1er*ice:
!ltral Ser$ices
− Nonmaterial bene4ts that #eo#le obtain $romecosystems: recreational0 aesthetic0 s#iritual0intellectual
− 3utdoor recreation and ecotourism are bi&
industries0 and contribute a si&ni4cant #ortion o$ B9, in some nations
− 3ri&inally #ercei*ed as bein& subJecti*e orluxuries only a*ailable to a minority o$indi*idualsX
Pro$isioning Ser$ices
− ,roducts that #eo#le obtain $rom ecosystems:?ood0 $uel0 4bers0 medicines
− ?ish is a core com#onent o$ #eo#les8 diets inmany #arts o$ the world0 where it is #rimarysource o$ #rotein $or 2FP o$ the #o#ulation
Reglating Ser$ices
− =ene4ts that #eo#le obtain $rom en*ironmentalre&ulation o$ ecosystem #rocesses:
− In wetland sediments0 #hysical0 chemical andbiolo&ical #rocesses #uri$y water by remo*in&nutrients0 toxins0 and human waste
− In estuaries0 bi*al*e molluscs0 includin& mussels0clams0 and oysters0 act as 4lterin& systems thatconsume al&ae secondary to eutro#hication andenhance #roducti*ity
− Man&ro*e $orests and salt marshes bu.er theland a&ainst ocean storm sur&es and #re*entcoastal erosion0 durin& normal and extreme/hurricane and tsunami e*ents!
Spporting Ser$ices
− 1er*ices necessary $or the #roduction o$ all otherecosystem ser*ices:
o ,rimary #roducti*ityo Nutrient cyclin&
o ,ollination
− Net #rimary #roduction is the amount o$ #lantmaterial #roduced durin& a year as a #roduct o$
#hotosynthesis− ?or the world8s ocean ecosystems N,, is
estimated to be around 2F billion metric tons0and it su##orts marine 4sheries and the cyclin&o$ nutrients in oceans
*cosystem Ser$ices
− maJor challen&e is to *alue in dollar terms allo$ these ecosystem ser*ices
− 3nly then can we understand the costs andbene4ts o$ enhancin&Sdiminishin& biodi*ersity inthe same currency as that on which mostdecisions