Photosythesis/respiration ratios in aquatic microcosms under arsenic stress

Journal Article · Sun Jan 01 04:00:00 EST 1978 · Water, Air, Soil Pollut.; (United States)

DOI:https://doi.org/10.1007/BF00280707· OSTI ID:6272857

Giddings, J; Eddlemon, G K

The ratio of net photosynthesis (P) to total ecosystem respiration (R) usually declines when an aquatic ecosystem is subjected to various types of stress. P/R ratios were measured in 12 80-1 microcosms containing water, sediment, and entire biotic communities (dominated by Elodea sp.) from a shallow pond. P and R were estimated from changes in dissolved O/sub 2/ concentrations during the day and night, respectively. After 10 weeks, the microcosms were stressed by the addition of sodium arsenate at concentrations of 0, 0.066, 11.5, and 143 ppM (as As). P/R ranged from 1.0 to 1.4 in all microcosms before arsenate was added. Under stress, both P and R declined in the 11.5 and 143 ppM microcosms, with negative net photosynthesis (i.e., decreases in dissolved O/sub 2/ during the day) observed on several occasions. P/R in these microcosms fell to zero or below, returning to 1.0 after three weeks. P/R remained above 1.0 in the 0.006 ppM and control microcosms. The P/R response could be used for screening suspected hazardoud substances in microcosms, as well as for monitoring natural ecosystems.

• Research Organization: Oak Ridge National Lab., TN
• OSTI ID: 6272857
• Journal Information: Water, Air, Soil Pollut.; (United States), Journal Name: Water, Air, Soil Pollut.; (United States) Vol. 9; ISSN WAPLA
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL COMPOUNDS
AQUATIC ECOSYSTEMS
ARSENIC
BIOLOGICAL STRESS
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
DOSE-RESPONSE RELATIONSHIPS
ECOSYSTEMS
ELEMENTS
FLUIDS
METABOLISM
NONMETALS
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
POLLUTION
PONDS
RESPIRATION
SEMIMETALS
SODIUM COMPOUNDS
SYNTHESIS
WATER POLLUTION