Impact of nitrogen and phosphorus release from a siliceous sediment on the overlying water
The release (+) or uptake (-) of ammonia (NH/sub 4//sup +/), nitrite (NO/sub 2//sup -/), nitrate (NO/sub 3//sup +/), phosphate (PO/sub 4//sup -3/) and dissolved organic phosphorus, nitrogen and carbon (DOP, DON, DOC) from a subtidal (18.3 m depth) siliceous sediment off La Jolla, California was studied over two years. The mean net exchange values (and the total range of rates obtained) were: NH/sub 4//sup +/ +872 ..mu.. mol m/sup -2/d/sup -1/ (-47 to +3290); NO/sub 2//sup -/ +34 ..mu.. mol m/sup -2/d/sup -1/ (-5 to +97); NO/sub 3//sup -/ -77 ..mu.. mol m/sup -2/d/sup -1/ (-720 to +647); PO/sub 4//sup -3/ +77 ..mu.. mol m/sup -2/d/sup -1/ (-438 to +502); DOP +12 ..mu.. mol m/sup -2/d/sup -1/ (-28 to +59); DON -75 ..mu.. mol m/sup -2/d/sup -1/ (-1326 to +1280); and DOC -583 ..mu.. mol m/sup -2/d/sup -1/ (-30,800 to +23,800). Using published primary production rates and C:N:P ratios it was calculated that 15,000 ..mu.. mol N m/sup -2/d/sup -1/ and 935 ..mu.. mol P m/sup -2/d/sup -1/ were taken up by the phytoplankton. The benthos released 786 ..mu.. mol N m/sup -2/d/sup -1/ and 90 ..mu.. mol P m/sup -2/d/sup -1/ or 5 percent and 10 percent of the required N and P. It was shown, however, that sediment exchange released only an insignificant fraction of both N (0.4 percent) and P (0.5 percent) already contained in the water. By using a conservative mean net advection rate of 1.5 km d/sup -1/ it must be presumed that the N and P released into the water at this site was superfluous to the needs of the phytoplankton and was, therefore, exported from the area.
- Research Organization:
- Johns Hopkins Univ., Baltimore, Md. (USA). Chesapeake Bay Inst.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- E(11-1)-3279
- OSTI ID:
- 7356570
- Report Number(s):
- COO-3279-20; CONF-7510111-2
- Resource Relation:
- Conference: 3. international estuarine conference, Galveston, TX, USA, Oct 1975
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMMONIA
ENVIRONMENTAL EFFECTS
CARBON
NITRATES
NITRITES
NITROGEN
CONTAMINATION
PHOSPHATES
PHOSPHORUS
PLANKTON
SEAWATER
SEDIMENTS
POLLUTION
SILICON
AQUATIC ORGANISMS
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
HYDRIDES
HYDROGEN COMPOUNDS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
SEMIMETALS
WATER
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)