Anoxia in a coastal bay: case study of a seasonal event
Rev. biol. trop
;
49(2): 525-533, Jun. 2001.
Article
in English
| LILACS
| ID: lil-333130
RESUMO
BahÝa Concepción (Gulf of California) was studied to describe some extremely low dissolved-oxygen values at the bottom of the bay. Surveys included measurements of vertical distribution of temperature, dissolved oxygen, nitrate, nitrite, phosphates and hydrogen sulfide. Thermal stratification from early spring to autumn and a well-mixed water column during the winter were present. Dissolved-oxygen concentration was homogeneous in the water column from winter to spring (5-7 mg L-1). From summer to autumn, bottom dissolved oxygen (> 20 m) decreased to reach conditions of hypoxia (1-2 mg L-1) or anoxia; nitrate, nitrite, and phosphates increased (up to 13, 1.7 and 2.2 microM) followed by a last short period of a deep hydrogen sulfide layer (up to 3.1 mg L-1). A back calculation to estimate the input of organic matter in the deep layer showed that 18 g C m-2 y-1 needed to be trapped in the bottom to induce such an oxygen depletion. This period is thought to be unfavorable for bottom infauna in this bay.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Oxygen
/
Seawater
Limits:
Animals
Country/Region as subject:
North America
Language:
English
Journal:
Rev. biol. trop
Journal subject:
Biology
/
Tropical Medicine
Year:
2001
Type:
Article
Affiliation country:
Mexico
Institution/Affiliation country:
Centro de Investigaciones Biológicas del Noroeste/MX
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