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Title: Eutrophication in the northern Adriatic Sea: Pore water and sediment studies

Abstract

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 moremore » 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.« less

Authors:
;  [1]; ; ; ;  [2]
  1. Univ. of Southern California, Los Angeles (United States)
  2. Inst. di Geologia Marina, CNR, Bologna (Italy)
Publication Date:
OSTI Identifier:
6881071
Report Number(s):
CONF-9002174-
Journal ID: ISSN 0096-3941; CODEN: EOSTAJ
Resource Type:
Conference
Journal Name:
EOS, Transactions, American Geophysical Union; (United States)
Additional Journal Information:
Journal Volume: 71:2; Conference: Ocean sciences meeting, New Orleans, LA (United States), 12-16 Feb 1990; Journal ID: ISSN 0096-3941
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 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-)

Citation Formats

Hammond, D E, Berelson, W M, Giordani, P, Langone, L, Frignani, M, and Ravaioli, M. Eutrophication in the northern Adriatic Sea: Pore water and sediment studies. United States: N. p., 1990. Web.
Hammond, D E, Berelson, W M, Giordani, P, Langone, L, Frignani, M, & Ravaioli, M. Eutrophication in the northern Adriatic Sea: Pore water and sediment studies. United States.
Hammond, D E, Berelson, W M, Giordani, P, Langone, L, Frignani, M, and Ravaioli, M. 1990. "Eutrophication in the northern Adriatic Sea: Pore water and sediment studies". United States.
@article{osti_6881071,
title = {Eutrophication in the northern Adriatic Sea: Pore water and sediment studies},
author = {Hammond, D E and Berelson, W M and Giordani, P and Langone, L and Frignani, M and Ravaioli, M},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/6881071}, journal = {EOS, Transactions, American Geophysical Union; (United States)},
issn = {0096-3941},
number = ,
volume = 71:2,
place = {United States},
year = {Tue Jan 09 00:00:00 EST 1990},
month = {Tue Jan 09 00:00:00 EST 1990}
}

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