Many regulatory frameworks for sediment quality assessment include consideration of contaminant bioavailability. However, the "snap-shots" of metal bioavailability provided by analyses of porewaters or acid-volatile sulfide-simultaneously extractable metal (AVS-SEM) relationships do not always contribute sufficient information. The use of inappropriate or inadequate information for assessing me...

This paper reports an experiment of using “artificial” sediments (mixed and DOM enriched) to simulate DIC and Alk fluxes (during inundation) and CO2 flux (during exposure) from subtidal mudflats. The authors also used an early diagenetic model to interpret and simulate the experiment output. (the latter is the focus of this paper) They found that CO2 flux (to atm during exposures) is generally ...

Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentra...

An empirical function is derived for predicting the rate-depth profile of particulate organic carbon (POC) degradation in surface marine sediments including the bioturbated layer. The rate takes the form of a power law analogous to the Middelburg function. The functional parameters were optimized by simulating measured benthic O2 and NO3 fluxes at 185 stations worldwide using a diagenetic model...

We performed a 15N-labeling study to investigate nitrogen incorporation and retention by the benthic microbial community (bacteria and benthic microalgae) and fauna in the intertidal sediment of the subtropical Australian Brunswick Estuary. The main experiment involved an in situ 15N pulse–chase experiment. After injection of 15NH z4 into the sediment, 15N was traced into bulk sediment, total h...

Estuaries play an important role in regulating nitrous oxide (N2O) fluxes to the atmosphere, but little is known about how catchment land-use changes influence benthic N2O cycling. We measured seasonal and constructed budgets three sub-tropical estuaries draining catchments with contrasting levels of intensity. Benthic habitats were a net sink minimally impacted Noosa River Estuary (?287 nmol m...

Oxygen minimum zones (OMZs) that impinge on continental margins favor the release of phosphorus (P) from the sediments to the water column, enhancing primary productivity and the maintenance or expansion of low-oxygen waters. A comprehensive field program in the Peruvian OMZ was undertaken to identify the sources of benthic P at six stations, including the analysis of particles from the water c...

The coastal region of central Chile (36 S) is one of the most productive coastal systems, characterized by a marked seasonality in the upwelling regime, that brings subsurface waters rich in nutrient and poor in oxygen (ESSW) into the euphotic zone. This oceanographic condition depends basically on the equatorward wind strength and is modified on different time scales, with the El Niño-Southern...

In shallow coastal ecosystems where most of the seafloor typically lies within the photic zone, benthic autotrophs dominate primary production and mediate nutrient cycling and sediment stability. Because of their different structure and metabolic rates, the 2 functional groups of benthic macrophytes (seagrasses, macroalgae) have distinct influences on benthic−pelagic coupling. Most research to ...

Monthly time-series data (1998–2009) of bottom water oxygen, nitrate and nitrite concentrations from the outer shelf (150m water depth) in the oxygen minimum zone offshore Peru were coupled to a layered biogeochemical sediment model to investigate benthic-pelagic coupling over multi-annual time scales. The model includes the mineralization of four reactive pools of particulate organic carbon (P...