Eutrophication in the northern Adriatic Sea: Pore water and sediment studies
- 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 (Po River being the largest) has increased nutrient input to this system and stimulated algal growth. Cores were collected for studies of pore water and solid phase chemistry at 6 stations in this region. [sup 210]Pb was used to constrain sediment accumulation rates and a range of 0-0.5 cm/yr was determined at different stations. Excess [sup 234]Th was only found in the upper 1-2 cm, suggesting that bioturbation is largely restricted to shallow depths. Pore water profiles show evidence of irrigation, and mean diffusive fluxes for oxygen, silica phosphate and ammonia are generally 20-90% of the fluxes obtained from benthic chamber measurements. This is consistent with previous work in this area in which studies of radon fluxes indicated that irrigation plays an important role in sediment-water exchange. Pore water profiles in the northern portion of the study area (near the Po River Delta) were markedly different than profiles in the south; sediments in the north are substantially more acidic and have high concentrations of dissolved iron and phosphate. From the alkalinity vs. TCO[sub 2] relationship in sediment pore waters it appears that differences in reactions involving the reduction of iron oxides and the exchange of magnesium for iron in clays are responsible for this regional difference in pore water properties. Sediments close to the Po apparently undergo more iron-magnesium exchange, while more distal sediments are limited in their ability to do so. Other pore water observations are limited in their ability to do so. Other pore water observations and trends regarding the shape of the silica profiles (which show shallow maxima) will be discussed.
- OSTI ID:
- 6881071
- 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
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Related Subjects
ADRIATIC SEA
EUTROPHICATION
INTERSTITIAL WATER
CHEMISTRY
SEDIMENTS
AMMONIA
AQUATIC ECOSYSTEMS
BUILDUP
CARBON
CLAYS
HUMAN POPULATIONS
IRON OXIDES
IRRIGATION
MAGNESIUM
MONITORING
NITROGEN
NUTRIENTS
ORGANIC WASTES
OXYGEN
PHOSPHORUS
PO RIVER
RADON
SILICON OXIDES
ALKALINE EARTH METALS
CHALCOGENIDES
ECOSYSTEMS
ELEMENTS
FLUIDS
GASES
GROUND WATER
HYDRIDES
HYDROGEN COMPOUNDS
IRON COMPOUNDS
MEDITERRANEAN SEA
METALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
POPULATIONS
RARE GASES
RIVERS
SEAS
SILICON COMPOUNDS
STREAMS
SURFACE WATERS
TRANSITION ELEMENT COMPOUNDS
WASTES
WATER
540310* - Environment
Aquatic- Basic Studies- (1990-)
540320 - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)