Absorption of ultraviolet radiation by antarctic phytoplankton

Conference · Tue Jan 09 04:00:00 EST 1990 · EOS, Transactions, American Geophysical Union; (United States)

OSTI ID:6657506

Vernet, M; Mitchell, B G ^[1]

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1. Univ. of California-San Diego, La Jolla (United States)

Antarctic phytoplankton contain UV-absorbing compounds that may block damaging radiation. Compounds that absorb from 320-340 nm were observed in spectral absorption of both particulates and in methanol extracts of the particulates. The decrease in the total concentration of these UV compounds with respect to chlorophyll a, as measured by the ratio of in vitro absorption at 335 nm to absorption at 665 nm is variable and decreases with depth. We observed up to 5-fold decrease in this ratio for samples within the physically mixes surface layer. The absorption of UV radiation in methanol extracts, which peaks from 320 to 340 nm, may be composed of several compounds. Shifts in peak absorption with depth (for example, from 331 nm at surface to 321 nm at 75 m), may be interpreted as a change in composition. Ratios of protective yellow xanthophylls (diadinoxanthin + diatoxanthin) to photosynthetic fucoxanthin-like pigments have highest values in surface waters. As these pigments also absorb in the near UV, their function might extend to protection as well as utilization of UV radiation for photosynthesis. We document strong absorption in the UV from 320-330 nm for Antarctic marine particulates. Below this region of the solar energy spectrum, absolute energy levels of incident radiation drop off dramatically. Only wavelengths shorter than about 320 nm will be significantly enhanced due to ozone depletion. If the absorption we observed serves a protective role for phytoplankton photosynthesis, it appears the peak band is in the region where solar energy increases rapidly, and not in the region where depletion would cause significant variations in absolute flux.

• OSTI ID: 6657506
• Report Number(s): CONF-9002174--
• Conference Information: Journal Name: EOS, Transactions, American Geophysical Union; (United States) Journal Volume: 71:2
• Country of Publication: United States
• Language: English

Related Subjects

560130* -- Radiation Effects on Microorganisms
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION
ANTARCTIC OCEAN
ANTARCTIC REGIONS
ANTARCTICA
AQUATIC ORGANISMS
BIOLOGICAL ADAPTATION
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLOROPHYLL
ELECTROMAGNETIC RADIATION
ENERGY
ENERGY LEVELS
ENERGY SOURCES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IN VITRO
LAYERS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OZONE LAYER
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYTOCHROMES
PHYTOPLANKTON
PIGMENTS
PLANKTON
PLANTS
POLAR REGIONS
PORPHYRINS
PROTEINS
RADIATIONS
RENEWABLE ENERGY SOURCES
SEAS
SOLAR ENERGY
SORPTION
SURFACE WATERS
SYNTHESIS
ULTRAVIOLET RADIATION