Control of Biological Exposure to UV Radiation in the Arctic Ocean: Comparison of the Roles of Ozone and Riverine Dissolved Organic Matter

Reports of severe stratospheric ozone depletion over the Arctic have heightened concern about the potential impact of rising ultraviolet-B (UV-B) radiation on north polar aquatic ecosystems. Our optical measurements and modelling results indicate that the ozone-related UV-B influence on food web pro...

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Bibliographic Details
Main Authors: Gibson, JAE, Vincent, WF, Nieke, B, Pienitz, R
Format: Article in Journal/Newspaper
Language:English
Published: 2000
Subjects:
260403 Physical Oceanography
260402 Chemical Oceanography
Arctic
CDOM
DNA
global change
ozone depletion
phytoplankton
Siberia
transparency
ultraviolet radiation
Arctic Ocean
Arctic Basin
Barrow
Climate change
Phytoplankton
Alaska
Online Access:https://eprints.utas.edu.au/868/
https://eprints.utas.edu.au/868/1/Arctic53-4-372.pdf
Description
Summary:Reports of severe stratospheric ozone depletion over the Arctic have heightened concern about the potential impact of rising ultraviolet-B (UV-B) radiation on north polar aquatic ecosystems. Our optical measurements and modelling results indicate that the ozone-related UV-B influence on food web processes in the Arctic Ocean is likely to be small relative to the effects caused by variation in the concentrations of natural UV-absorbing compounds, known as chromophoric dissolved organic matter(CDOM), that enter the Arctic basin via its large river inflows. The aim of our present study was to develop and apply a simple bio-optical index that takes into account the combined effects of attenuation by atmospheric ozone and water column CDOM, and photobiological weighting for high-latitude environments such as the Arctic Ocean. To this end, we computed values for a biologically effective UV dose rate parameter ('weighted transparency' or T*) based on underwater UV measurements in highlatitude lakes and rivers that discharge into the Arctic Ocean; measured incident UV radiation at Barrow, Alaska; and published biological weighting curves for UV-induced DNA damage and UV photoinhibition of photosynthesis. The results underscore how strongly the Arctic Ocean is influenced by riverine inputs: shifts in CDOM loading (e.g., through climate change, land-use practices, or changes in ocean circulation) can cause variations in biological UV exposure of much greater magnitude than ozone related effects.

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