Eutrophication in the northern Adriatic Sea: Benthic fluxes and nutrient budgets
- Univ. of Southern California, Los Angeles (United States)
- Inst. di Geologia Marina-CNR, Bologna (Italy)
The northern Adriatic Sea has been plagued by problems of eutrophication. This area is relatively shallow (maximum depth = 60m), becoming stratified during the summer months which inhibits oxygen transport to bottom waters. Anthropogenic nutrient loading in rivers entering the northern Adriatic has increased nutrient input to this system and stimulated algai growth. Five stations in the western Adriatic (south of the Po River Delta) were occupied during September, 1988 and benthic flux chambers used to measure nutrient fluxes. These sites included 3 stations previously studied in 1982. Flux measurements of dissolved silica, nitrate, oxygen, ammonia, phosphate, CO[sub 2], alkalinity and radon were made during 24 hour incubations of flux chambers (area covered - 0.07 m[sup 2], volume = [approximately]81) that were continuously stirred and sampled periodically. Nutrient fluxes measured were generally consistent with the fluxes measured previously in June, 1982 except for radon fluxes which were 203 times greater in the earlier field season. There was a general trend in nutrient fluxes to decrease offshore, a pattern probably controlled by the sedimentation patterns because fine grained, organic matter-rich sediment are concentrated in a zone near shore. Average regional fluxes were (in mmol m[sup -2]d[sup -1], negative values indicate flux into sediment): Oxygen (-12), CO[sub 2] (19), Alkalinity (4), Silica (3.3), Ammonia (1.5), Phosphate (0.1) and Nitrate (0.3). The carbon/ammonia flux ratio is about twice the C/N ratio in marine phytoplankton, suggesting that large amounts of denitrification may be occuring in these sediments. Comparisons of benthic fluxes and sediment burial rates indicate that 50-90% of the carbon, silica, phosphorus and nitrogen arriving at the sediment-water interface is recycled before burial. The nutrient input to the water column from NW Adriatic sediments is about equal to the input from coastal rivers.
- OSTI ID:
- 6654913
- Report Number(s):
- CONF-9002174-; CODEN: EOSTAJ
- Journal Information:
- EOS, Transactions, American Geophysical Union; (United States), Vol. 71:2; Conference: Ocean sciences meeting, New Orleans, LA (United States), 12-16 Feb 1990; ISSN 0096-3941
- Country of Publication:
- United States
- Language:
- English
Similar Records
Benthic fluxes and the cycling of biogenic silica and carbon in two southern California borderland basins
Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria
Related Subjects
ADRIATIC SEA
EUTROPHICATION
AQUATIC ECOSYSTEMS
MONITORING
NUTRIENTS
AMMONIA
BUDGETS
CARBON
DENITRIFICATION
HUMAN POPULATIONS
NITROGEN
ORGANIC MATTER
ORGANIC WASTES
OXYGEN
OXYGEN 12
PHOSPHORUS
PHYTOPLANKTON
PO RIVER
RADON
RIVERS
SEDIMENTATION
SEDIMENTS
AQUATIC ORGANISMS
CHEMICAL REACTIONS
ECOSYSTEMS
ELEMENTS
EVEN-EVEN NUCLEI
FLUIDS
GASES
HYDRIDES
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MATTER
MEDITERRANEAN SEA
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
NUCLEI
OXYGEN ISOTOPES
PLANKTON
PLANTS
POPULATIONS
RARE GASES
SEAS
STREAMS
SURFACE WATERS
WASTES
540310* - Environment
Aquatic- Basic Studies- (1990-)
540320 - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)