Effects of Solar UV Radiation on Aquatic Ecosystems and Interactions
with Climate Change
D.-P. Häder, H. D. Kumar, R. C. Smith and R. C. Worrest
Recent results continue to show the general consensus that ozone-related
increases in UV-B radiation can negatively influence many aquatic
species and aquatic ecosystems (e.g., lakes, rivers, marshes, oceans).
Solar UV radiation penetrates to ecological significant depths in
aquatic systems and can affect both marine and freshwater systems from
major biomass producers (phytoplankton) to consumers (e.g., zooplankton,
fish, etc.) higher in the food web. Many factors influence the depth of
penetration of radiation into natural waters including dissolved organic
compounds whose concentration and chemical composition are likely to be
influenced by future climate and UV radiation variability. There is also
considerable evidence that aquatic species utilize many mechanisms for
photoprotection against excessive radiation. Often, these protective
mechanisms pose conflicting selection pressures on species making UV
radiation an additional stressor on the organism. It is at the ecosystem
level where assessments of anthropogenic climate change and UV-related
effects are interrelated and where much recent research has been
directed. Several studies suggest that the influence of UV-B at the
ecosystem level may be more pronounced on community and trophic level
structure, and hence on subsequent biogeochemical cycles, than on
biomass levels per se.
http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleForFree.cfm?doi=b700020k&JournalCode=PP%20
MA/NY DDave wrote:
> Hi Brian, EnviroNetrs,
>
> Still haven't found the article on organisms in the upper (not sub) ocean that
> may have been involved with a huge previous Global Warming spell, YET I
> found this one that I thought my interest you since you are an expert on
> Ozone. You might already have it. For others it should be interesting to see
> some of the science involved.
>
> http://gsa.confex.com/gsa/2005ESP/finalprogram/abstract_88582.htm
>
> <The spores and pollen of terrestrial land plants can increase their investment
> in UV-B screening pigments when exposed to elevated levels of UV-B radiation.
> Here, we report an increase in UV-B protecting pigments from a historical
> record of the spores of Lycopodium magellanicum growing in South Georgia and
> exposed to a progressive thinning of stratospheric ozone and a corresponding
> increase in UV-B radiation. Our data records a strong three fold linear increase
> in the concentration of UV-B protecting pigments in response to a 14%
> thinning of the ozone column. Our results were obtained using micro FT-IR
> analysis of sporopollenin, which is readily preserved in the fossil record.
> Therefore, this newly identified response offers a potential tool for
> investigating natural changes in the stratospheric ozone layer and UV-B flux
> over geological time.
>
> We are initially targeting the Permo-Triassic boundary for further investigation,
> as recent work has suggested a global collapse in the stratospheric ozone due
> to the emplacement of the Siberian Traps. This hypothesis can now be
> thoroughly tested using a combined approach, involving the examination of
> extant plants subjected to experimentally manipulated UV-B radiation, the
> geochemical study of fossil spores and pollen and the long-term modelling of
> stratospheric ozone.
>
> Earth System Processes 2 (8-11 August 2005)
>
> YiEngr, MA/NY DDave
> Yours in Engineering, Dave
>
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