Geoscience Reference
In-Depth Information
Richardson.2002)..In.addition,.some.ish.species.use.surf.zones.as.nurseries.(Lasiak.
1981;.Lenanton.and.Caputi.1989;.J..M..Leis.pers..com.).and.feed.on.beach.inverte-
brates.(Du.Preez.et.al..1990).
Sandy. beaches. are. also. linked. to. other. ecosystems. through. the. movements. of.
animals. that. occupy. the. beach. for. only. part. of. their. life. cycle.. For. example,. the.
beach.is.an.essential.transitory.element.in.the.long-distance.migrations.of.birds.and.
turtles.(Bouchard.and.Bjorndal.2000;.Colombini.and.Chelazzi.2003)..Also,.many.
invertebrates.occupy.the.beach.as.adults.but.their.dispersive.larvae.have.an.oceanic.
existence.as.plankton.
Because. of. these. links,. climate-change. factors. may. affect. beaches. indirectly.
through. their. effects. on. adjacent. systems.. For. example,. if. near-shore. planktonic.
productivity.changes.because.of.climate-induced.hydrological.changes.(Barth.et.al..
2007;.Rost.et.al..2008),.the.consequences.for.intertidal.invertebrates.will.be.large..
Also,.the.supply.of.sediment.to.beaches.will.fall.if.there.is.increased.damming.of.riv-
ers.to.compensate.for.less.rain.(Sherman.et.al..2002;.Finkl.and.Walker.2004).and.if.
increased.acidity.reduces.the.offshore.biological.production.of.carbonate.sediments.
CLIMATE CHANGE
Climate. change. encompasses. several. different. environmental. changes.. These.
have. been. categorized. hierarchically. by. Cocks. and. Crossland. (1991)
.
into. primary.
changes.(higher.atmospheric.CO
2
.concentrations.and.air.temperatures),.consequent.
second-order.effects.(increased.storminess,.warmer.water.with.reduced.pH,.changed.
rainfall.affecting.water.and.sediment.lows.to.the.coast),.third-order.(sea-level.rise.
and.changed.hydrology),.and.lower-order.effects.(saltwater.intrusion.into.aquifers,.
changes.to.streamlow,.beach.erosion,.and.coastal.retreat)..Each.of.these.factors.has.
the. potential. to. affect. beaches. directly. and. indirectly.. Moreover,. the. disturbances.
generated.by.climate.change.fall.into.the.categories.of.disturbance.that.are.of.partic-
ular.concern.(Dovers.et.al..1996;.Salafsky.et.al..2002;.Jones.2003b)..These.include
•.
Disturbances.of.very.large.scale.and/or.momentum..These.change.the.global.
ecological. theater. with. potentially. severe. consequences. for. ecosystems.
and.humans.alike.(Vitousek.et.al..1997;.IPCC.2002;.Stenseth.et.al..2002)..
Erosion.and.acidiication.are.climate-related.examples.relevant.to.beaches.
•.
Disturbances. that. persist,. i.e.,. press. disturbances. (Bender. et. al.. 1984)..
Increased.acidity.constitutes.a.press.disturbance..It.is.likely.that.the.ecologi-
cal.effects.will.be.great.and.persistent.(Orr.et.al..2005;.Turley.et.al..2005;.
Vezina.and.Hoegh-Guldberg.2008).unless.the.steady.increase.in.acidity.is.
suficiently.slow.for.physiological.acclimation.or.evolutionary.adaptation.to.
occur..Beach.biota.are.particularly.vulnerable.to.increased.acidity.because.so.
many.species,.especially.mollusks.and.crustaceans,.are.calcium.dependent.
•.
Disturbances.that.do.not.persist,.i.e.,.pulse.disturbances.(Bender.et.al..1984)..
Storms.and.pollution.are.examples..Once.these.abate,.ecological.recovery.is.
likely.to.occur.(Ansell.1983)..Consequently,.pulse.disturbances.are.less.seri-
ous.than.press.disturbances,.although.the.immediate.impacts.may.be.large.
