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Ultraviolet radiation and bio-optics in Crater Lake, Oregon

Hydrobiologia

By:
, , , , , and
DOI: 10.1007/s10750-006-0348-0

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Abstract

Crater Lake, Oregon, is a mid-latitude caldera lake famous for its depth (594 m) and blue color. Recent underwater spectral measurements of solar radiation (300-800 nm) support earlier observations of unusual transparency and extend these to UV-B wavelengths. New data suggest that penetration of solar UVR into Crater Lake has a significant ecological impact. Evidence includes a correlation between water column chlorophyll-a and stratospheric ozone since 1984, the scarcity of organisms in the upper water column, and apparent UV screening pigments in phytoplankton that vary with depth. The lowest UV-B diffuse attenuation coefficients (K d,320) were similar to those reported for the clearest natural waters elsewhere, and were lower than estimates for pure water published in 1981. Optical proxies for UVR attenuation were correlated with chlorophyll-a concentration (0-30 m) during typical dry summer months from 1984 to 2002. Using all proxies and measurements of UV transparency, decadal and longer cycles were apparent but no long-term trend since the first optical measurement in 1896. ?? 2007 Springer Science+Business Media B.V.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Ultraviolet radiation and bio-optics in Crater Lake, Oregon
Series title:
Hydrobiologia
DOI:
10.1007/s10750-006-0348-0
Volume
574
Issue:
1
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Hydrobiologia
First page:
107
Last page:
140