Size-fractionated particulate 234Th and particulate organic carbon (POC) fluxes were measured in the Gulf of Mexico during 2000 and 2001 in order to obtain a better estimation of upper ocean organic carbon export out of the euphotic zone within cold core and warm core rings, and to assess the relative merit of sediment trap and POC/234Th methods. In 2000, the flux of POC measured by sediment tr...

Vertical distributions of biogenic silica (bSi), particulate inorganic carbon (PIC) and key biomineral-forming phytoplankton indicate vertical zoning, or partitioning, during the late summer stratified period in northeast Atlantic. Coccolithophores were generally more numerous surface mixed layer, whilst PIC concentrations homogenous with depth throughout euphotic zone. Diatoms notably abundant...

The biological carbon pump transports photosynthetically fixed from surface waters to depths. It removes the atmosphere and sequesters it in deep ocean, playing an important role global climate regulation. As is directly related processes, heavily influenced by biomass trophic interactions between populations ecosystem. However, behavioral responses adaptations predation risk change interaction...

The Um Alhool area in Qatar is a dynamic evaporative ecosystem that receives seawater from below as it is surrounded by sand dunes. We investigated the chemical composition, the microbial activity and biodiversity of the four main layers (L1-L4) in the photosynthetic mats. Chlorophyll a (Chl a) concentration and distribution (measured by HPLC and hyperspectral imaging, respectively), the phycoc...

Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract The lipid content of seven samples of sinking particles collected with sediment traps moored at ∼100 m depth in summer and fall across the Canadian Beaufort Shelf (Arc-tic Ocean) was investigated. Our main goal ...

Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K(0.75)) was used as an indicator of phytoplankton concentration....

During the Austral summer of 2006–07 a series of extreme oceanic events occurred in the Tasman Sea. Following a series of strong wind-driven upwelling events, an intense cold-core eddy developed off Sydney, Australia. A data-assimilating, eddy-resolving ocean model is used to create a threedimensional time-varying reanalysis of these events. The reanalysis indicates that the cold anomalies asso...

A novel method for the measurement of dissolved adenosine-5'-triphosphate and guanosine-5'-triphosphate (D-ATP and D-GTP, respectively) in marine and freshwater habitats was developed and applied to samples collected from the oligotrophic North Pacific Ocean. Both D-ATP and D-GTP are co-precipitated by authigenically formed Mg(OH)(2) and can be concentrated by factors greater than 200-fold, for...

The light effect on photoheterotrophic processes in Prochlorococcus, and primary and bacterial productivity in the oligotrophic North Pacific Subtropical Gyre was investigated using (14)C-bicarbonate and (3)H-leucine. Light and dark incubation experiments were conducted in situ throughout the euphotic zone (0-175 m) on nine expeditions to Station ALOHA over a 3-year period. Photosynthetrons wer...