Nitrogen
fixation in coral reef
The
supply of nitrogen and phosphorus has long been a critical
question for workers in the field of coral reefs (Odum
and Odum 1955;
Wiebe et al.
1975).
In contrast to the tropical oceanic waters in which they are
found, coral reefs have some of the highest diversities and
productivities of any ecosystem known (Hatcher
1990).
Coral atolls found in the Indo-Pacific region commonly have a
rim surrounding a relatively deep lagoon. In terms of area and
volume, the lagoon may often be the most significant component
of the system.
Theoretically,
nitrogen can be supplied to coral reefs by at least two
processes: (1) exogenous input and/or (2) atmospheric dinitrogen
fixation by dinitrogen-fixing organisms. The latter process
appears to make a major contribution (Wilkinson
et al. 1984;
Larkum et al.
1988;
O'Neil and Capone 1989).
Biological dinitrogen fixation is a characteristic feature of
many marine benthic photosynthetic communities (Capone
1983;
Stal et al.
1984),
of which cyanobacteria are the most common dinitrogen fixers (Mague
and Holm-Hansen 1975;
Potts and Whitton
1977).
While many studies of dinitrogen fixation have focused on the
hard coral substrata of coral reefs, only rarely have
investigations focused on the soft substrata of the lagoon (O'Neil
and Capone 1989).
This is a serious omission in many coral atolls, where the
lagoon surface area may be huge compared to the surface area of
hard substrata.
This
page was based on :
Charpy-Roubaud
C., Charpy L., Larkum A.W. (2001) Atmospheric dinitrogen
fixation by benthic communities of Tikehau Lagoon (Tuamotu
Archipelago, French Polynesia) and its contribution to benthic
primary production. Mar. Biol. 139: 991-997
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