Geoscience Reference
In-Depth Information
At. the. terrestrial. surface,. UV-B. radiation. is. extremely. important. biologically..
Critical.biomolecules.absorb.light.of.higher.wavelength.(UV-A;.315-400.nm).less.
eficiently,.and.stratospheric.ozone.absorbs.most.light.of.lower.wavelength.(UV-C;.
200-280.nm).(Cockell.and.Blaustein.2001)..UV-B.radiation.can.cause.mutations.and.
cell.death.(Tevini.1993;.Cockell.and.Blaustein.2001)..At.the.individual.level,.UV-B.
radiation. can. slow. growth. rates,. cause. immune. dysfunction,. and. induce. sublethal.
damage.(Tevini.1993).
UV-B.radiation.has.been.a.ubiquitous.stressor.on.living.organisms.over.evolution-
ary.time.(Cockell.2001)..Natural.events.such.as.impacts.from.asteroids.and.comets,.
volcanic.activity,.cosmic.events.such.as.supernova.explosions,.and.solar.lares.can.
cause. large-scale. ozone. depletion. with. accompanying. increases. in. UV. radiation.
(Cockell.2001)..However,.these.natural.events.are.transitory.and.may.only.have.sig-
niicant.effects.on.stratospheric.ozone.for.a.few.years.
This. is. markedly. different. from. human-induced. production. of. CFCs. and. other.
chemicals. that. are. continuously. depleting. stratospheric. ozone,. inducing. long-term.
increases.in.UV-B.radiation.at.the.surface..Decreases.in.stratospheric.ozone,.climate.
warming,. and. lake. acidiication. leading. to. decreases. in. dissolved. organic. carbon.
concentrations. (e.g.,. Schindler. et. al.. 1996). all. result. in. increasing. levels. of. UV-B.
radiation..Levels.of.UV-B.radiation.have.risen.signiicantly.in.modern.times.(espe-
cially.since.1979).both.in.the.tropics.and.in.temperate.regions.(Kerr.and.McElroy.
1993;.Herman.et.al..1996;.Middleton.et.al..2001).
UV-B.radiation.adversely.affects.a.wide.variety.of.organisms.including.amphib-
ians. (e.g.,. Tevini. 1993;. Cockell. and. Blaustein. 2001;. Bancroft. et. al.. 2007,. 2008a;.
Croteau.et.al..2008)..Moreover,.UV-B.radiation.may.interact.with.other.stressors.to.
affect. a. wide. array. of. organisms. and. entire. ecological. communities. (Tevini. 1993;.
van.der.Leun.et.al..1998;.Cockell.and.Blaustein.2001;.Bancroft.et.al..2007).
Living.organisms.have.had.fewer.than.100.years.to.cope.with.a.gradual.human-
induced.rise.in.UV.radiation..Combined.effects.of.UV-B.radiation.with.pollutants,.
pesticides,.and.other.agents.that.have.been.on.earth.for.a.relatively.short.period.of.
time. may. be. especially. damaging. to. organisms. that. have. not. had. time. to. develop.
mechanisms. to. survive. their. effects.. Indeed,. environmental. change. and. contami-
nation. appear. to. be. contributing. to. the. current. unprecedented. loss. in. biodiversity.
(Eldridge.1998).
The. diversity. of. locations. where. amphibian. populations. have. declined. has.
prompted.consideration.of.global.environmental.changes..Climate.change.and.other.
changes.in.the.environment.that.are.global.in.nature.have.been.recognized.as.poten-
tial.problems.for.amphibian.populations.by.a.number.of.investigators.(e.g.,.Ovaska.
1997;.Donnelly.and.Crump.1998;.Alford.and.Richards.1999;.Alexander.and.Eischeid.
2001;.Blaustein.et.al..2003;.Carey.and.Alexander.2003;.Blaustein.et.al..2010).
Ovaska.(1997).suggested.that.climate.warming.may.result.in.both.beneicial.and.
deleterious. effects. on. amphibians.. For. example,. it. was. suggested. that. anticipated.
temperature.increases.in.winter.may.be.beneicial.for.amphibians.in.some.regions.of.
Canada,.whereas.anticipated.decreases.in.precipitation.in.combination.with.elevated.
temperatures.and.evaporation.in.summer.may.be.harmful.to.some.species..Moreover,.
Ovaska.(1997).described.how.changes.in.temperature.and.moisture.could.inluence.
amphibian.behavior.physiology.and.life.history.events..For.example,.Ovaska.(1997).
