Benthic flux studies in Narragansett Bay

Elderfield, Henry; Luedtke, Nile A.; McCaffrey, R. J.; Bender, Michael L.

doi:10.2475/ajs.281.6.768

Cited by 101 publications

(33 citation statements)

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“…It is evident that, in addition to the influence of the Danube, the benthic processes in the high flux area are highly relevant for the nutrient balance of the Black Sea. However, the benthic nutrient supply in the coastal zone of the Black Sea is still only about half of that determined for Naragansett Bay (Elderfield et al, 1981) and Chesapeake Bay (Callender & Hammond, 1982).…”

Section: Flux Balancementioning

confidence: 99%

Benthic Nutrient Cycling and Diagenetic Pathways in the North-western Black Sea

Friedrich

Dinkel

Friedl

et al. 2002

Estuarine, Coastal and Shelf Science

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Benthic fluxes of nutrients and metals were measured in the coastal zone of the north-western Black Sea, which is influenced by the Danube and Dniestr rivers. The results from the benthic flux chambers deployed during two EROS 21 cruises in summer 1995 and in spring 1997 yield information on benthic nutrient cycling and diagenetic pathways at the sediment-water interface. This information is discussed in the light of benthic activity as well as pore-water data. The benthic recycling of nutrients varied seasonally due to the availability of oxygen and organic material, and spatially due to river influence. Areas of high benthic fluxes near-shore and of low benthic fluxes offshore on the shelf were distinguished. Nutrients and suspended particulate matter discharged by the Danube is kept nearshore by the coastal current. The oxygen concentrations in the bottom water varied strongly between the two seasons. In summer, the bottom water at the near-shore stations turned anoxic. In spring, the higher oxygen concentrations are related to more intense mixing of the water column due to stormy periods and high river discharge. Highest oxygen concentrations were found on the offshore continental shelf. However, the benthic oxygen consumption rates in spring (13-23 mmol m 2 day 1 ) were as high as in summer. Areas with highest nutrient concentrations in the overlaying bottom water were found at the Danube delta front and Danube prodelta. On the Danube delta front and the Dniestr mouth, ammonia fluxes were lower in spring (1·1-1·7 mmol m 2 day 1 ) than in the summer (2·6-4·4 mmol m 2 day 1 ) due to higher nitrification rates and the lower influx of organic matter. In spring, the concentrations of dissolved iron and manganese in the bottom water were one order of magnitude lower than during the summer. This decrease in flux rates is related to the higher oxygen concentrations in the bottom water in spring. A rough comparison of the river's nutrient load and the benthic recycling over a certain area showed that the near-shore benthic phosphate and silica recycling account for 50% and 35% of the Danube input in summer, respectively. The fluxes of ammonia from benthic recycling and from the Danube discharge were at the same order of magnitude in both seasons. Nitrogen is introduced by the rivers mostly as nitrate. Benthic recycling is the dominant source of ammonia. The Danube input is phosphate deficient. In brief, benthic nutrient recycling is an important factor in sustaining high productivity of the system.

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Section: Flux Balancementioning

confidence: 99%

Benthic Nutrient Cycling and Diagenetic Pathways in the North-western Black Sea

Friedrich

Dinkel

Friedl

et al. 2002

Estuarine, Coastal and Shelf Science

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“…Elderfield et al (1981) found highest fluxes at a low salinity station in Naragansett Bay (this station also was closest, of the 3 studied, to a sewage outfall). While the data of Callender & Hammond (1982) suggest no clear pattern for NH: flux in the Potomac estuary, highest DIP fluxes occurred consistently at salinities similar to those where we found maximum rates.…”

Section: Sediment Nutrient Profilesmentioning

confidence: 99%

“…Distinct changes in sediment pore-water constituents and associated diagenic processes have been documented also along the salinity transitions for a few estuaries (Martens & Goldhaber 1978). Relations between net f l u e s of nutrients and other dissolved substances at the sediment surface and pore-water concentrations have been investigated for individual sites in a given estuary (Elderfield et al 1981, Klump & Martens 1981, and Callender & Hammond (1982) examined such relations along the length of the Potomac River estuary. However, interaction between water column and sediment properties in relation to exchanges across the Contribution No.…”

Section: Introductionmentioning

confidence: 99%

Nutrient regeneration and oxygen consumption by sediments along an estuarine salinity gradient

Boynton¹,

Kemp²

1985

Mar. Ecol. Prog. Ser.

297

126

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Nutrient fluxes and oxygen consumption (SOD) across the sediment-water interface were measured in situ along with vertical profiles of dissolved and particulate-phase nutrients in sediments and overlying water at 8 locations along the salinity gradient of Chesapeake Bay during spring and summer. Strong spatial and temporal patterns were evident. Highest rates of sediment NH: regeneration and SOD occurred in summer at mid-salinity (12 to 17 %a) stations. Sediment fluxes of dissolved inorganic phosphorous (DIP) were always low, possibly due to relatively oxidized conditions in surficial sediments. Nitrate (NO;) fluxes generally were directed into the sedirnents in spring and from the sediments during summer, and in both seasons fluxes were proportional to NO3 concentrations in overlying waters. Seasonal shifts in sediment 0:N flux ratios suggest that denitrification may have been important in spring but not summer. Significant relations were inferred between C:N:P composition of suspended materials and surficial sediments and the magnitude and direction of sediment-water fluxes. Although accretion of particulate nitrogen in sediments was less than 6 % of NH: regeneration in the lower bay, it was similar to rates of NH: flux in the low salinity region, suggesting that burial represents a significant sink for N in some estuarine zones. SOD constituted an important term in water column O2 budgets at all stations (1G50 % of total respiration), and sediment regeneration of NH: was capable of supplying 13 to 40 % of calculated phytoplankton N requirement, being more important during the summer period of higher productivity.

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“…The distribution of snow cover on sea ice appears to control ice algae distributions (Alexander and Chapman 1981). Biological irrigation in sediments also varies in time and space and seems to be most active in late summer (Martens and Berner 1977;Elderfield et al 1981).…”

Section: Discussionmentioning

confidence: 99%

Fluxes associated with brine motion in growing sea ice

Reeburgh

1984

Polar Biol

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Summary. Laboratory and field studies have demonstrated that fluid motion occurs at two locations in growing sea ice: in a network of brine channels and within the skeletal layer at the ice-water interface. Brine channel fluxes estimated using brine channel areal density from natural sea ice and channel velocities from laboratory studies are compared with recent measurements reported in the literature. Fluxes into the porous skeletal layer of sea ice may be estimated using rates of nutrient uptake by ice algae and adjacent seawater nutrient concentrations. Both approaches indicate fluxes of the order of 10 -6 cc cm -2 s -1 (1 m -2 h-l), which are about equal to fluxes reported in bioirrigated sediments. Fluxes of this magnitude indicate a very short residence time for the liquid phase in the skeletal layer, suggesting that this fluid motion may be important in maintaining the ice algae community.

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Benthic flux studies in Narragansett Bay

Cited by 101 publications

References 0 publications

Benthic Nutrient Cycling and Diagenetic Pathways in the North-western Black Sea

Benthic Nutrient Cycling and Diagenetic Pathways in the North-western Black Sea

Nutrient regeneration and oxygen consumption by sediments along an estuarine salinity gradient

Fluxes associated with brine motion in growing sea ice

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