Abstract
Benthic photosynthetic microorganisms are widespread in shallow-water sediments, microenvironments that are commonly assumed to be virtually opaque to ultraviolet radiation (UVR). We used a newly developed optical microprobe to measure the submillimeter penetration of solar UVR into a variety of these microenvironments. UVR trapping due to strong scattering occurred at the surface of some sediments, resulting in a surface maximum of scalar irradiance (E0) that could be significantly larger that the incident radiation. In the subsurface, E0 was typically extinguished in a quasi- exponential manner, with attenuation coefficients (310 nm) ranging from 4 to 21 mm-1, depending on sediment type. Ultraviolet B (at 310 nm) was extinguished to 1% of the incident between 1.25 and 0.23 mm from the surface. Within the euphotic zones of these sediments, however, the space- averaged UVB scalar irradiance was very high, between 15 and 33% of the incident. In natural waters, for example, the same parameter varies between 3 and 9% of the incident. Thus, in fact, photosynthesis in these environments must develop under strong UV stress, and it must be regarded as potentially labile to the effects of ozone depletion.
Original language | English (US) |
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Pages (from-to) | 257-262 |
Number of pages | 6 |
Journal | Marine Ecology Progress Series |
Volume | 131 |
Issue number | 1-3 |
DOIs | |
State | Published - Feb 8 1996 |
Externally published | Yes |
Keywords
- Primary productivity
- Sediments
- Ultraviolet radiation
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science
- Ecology