ISSN:
1573-5117
Keywords:
tropical lagoon
;
autotrophic activity
;
heterotrophic activity
;
pelagic carbon metabolism
;
benthic carbon metabolism
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Pelagic and benthic carbon metabolism in the shallow tropical Barra Lagoon was studied weekly between 1990 and 1993, in periods characterized by temporary nitrogen limitation, fish kills and transitory colonization of the bottom by macro-algae. Diurnal and nocturnal metabolic rates were measured by monitoring changes in CO2 content in entire water columns (free water and waters incubated in plexiglass tubes with and without inclusion of sediment). Total community carbon metabolism exhibited a marked autotrophism and high short term changes, dampening seasonal trends. Autotrophism and heterotrophism of the lagoon were controlled by phytoplankton biomass variations. In the presence of sediment, diurnal net benthic production was 11 to 64% of total diurnal net production, and nocturnal net benthic mineralization was 21 to 52% of total nocturnal net mineralization. The imbrication between the pelagic and benthic organic carbon cycles regulated carbon metabolism of the total community. A severe temporary nitrogen limitation, a fish kill and a temporary shift in primary producers did not substantially change metabolic rates because appropriate shifts occurred from the pelagic carbon cycle to the benthic carbon cycle, and vice-versa.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1017048128271
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