Benthic fluxes of dissolved ferrous iron (Fe2+) and phosphate (TPO4) were quantified by in situ benthic chamber incubations and pore-water profiles along a depth transect (11uS, 80–1000 m) across the Peruvian oxygen minimum zone (OMZ). Bottom-water O2 levels were , 2 mmol L21 down to 500-m water depth, and increased to , 40 mmol L21 at 1000 m. Fe2+ fluxes were highest on the shallow shelf (maxi...

Estuarine planktonic bacteria were incubated (bacterial bioassays) in water previously held in close contact with benthic sediments to assess the potential importance of benthic dissolved organic matter for planktonic bacterial production. The study was conducted using water and sediments collected from along a fresh to salt water gradient in the Parker River and Plum Island Sound Estuary in no...

determined from the downward vertical flux of pheopigments. Improved extraction of chlorophyll a and b from algae using dimethylsulfoxide. Limnol. zooplankton reproduction: Implications for diel vertical migration theory. Abstract-We report the first seasonal time-series observations of porewater composition obtained for deep-sea sediments. We observed considerable temporal variability of O,, N...

A field experiment to compare methods of assessing submarine groundwater discharge (SGD) was held on Shelter Island, NY, in May 2002. We evaluated the use of radon, radium isotopes, and methane to assess SGD rates and dynamics from a glacial aquifer in the coastal zone. Fluxes of radon across the sediment-water interface were calculated from changes in measured surface water inventories followi...

In the present study, changes in benthic communities due to seasonal changes in the water of the southern Caspian Basin were investigated. Sampling was conducted monthly, from March 2006 to March 2007, at six selected stations in Tajan River mouth located on south eastern Caspian Sea. Also secondary benthic production consumable for fish and other biota inhabiting the mouth and adjacent areas w...

Sulfate reduction rates in the surface sediments from 17 stations from an along-slope transect (1,300 m) and from a cross-slope transect (855–4,766 m) were determined in the continental margin sediments of the Benguela Upwelling system. Profiles at all sites in the upwelling area showed increasing sulfate reduction rates from near zero at the surface to a peak at 2–5 cm (up to 29 nmol cm23 d21)...

Lampreys spend their larval stage within fine sand fluvial sediments, where they burrow and act as filter feeders. Lamprey larvae (ammocoetes) can significantly affect benthic-pelagic coupling nutrient cycling in rivers, due to high densities. However, bioturbation, feeding excretion activities are still poorly explored. These aspects were investigated by means of laboratory incubations intact ...

The past decades have seen remarkable changes in the Arctic, a hotspot for climate change. Nevertheless, impacts of such changes on the biogeochemical cycles and Arctic marine ecosystems are still largely unknown. During cruises to the deep-sea observatory HAUSGARTEN in July 2007 and 2008, we investigated the biogeochemical recycling of organic matter in Arctic margin sediments by performing sh...

Exchange of gases, such as O2, CO2, and CH4, over the air–water interface is an important component in aquatic ecosystem studies, but exchange rates are typically measured or estimated with substantial uncertainties. This diminishes the precision of common ecosystem assessments associated with gas exchanges such as primary production, respiration, and greenhouse gas emission. Here, we used the ...

Oxygen fluxes across the sediment–water interface reflect primary production and organic matter degradation in coastal sediments and thus provide data that can be used for assessing ecosystem function, carbon cycling and the response to coastal eutrophication. In this study, the aquatic eddy covariance technique was used to measure seafloor– water column oxygen fluxes at shallow coastal sites w...