The North Pacific subtropical gyre (NPSG), once considered to be a biological desert due to low primary production (PP) and its associated variability, has been found more productive and variable than previously thought. The environmental conditions controlling this relatively high PP variability are yet to be elucidated, despite important implications...
This study investigated the composition and character of organic matter on suspended particulate material (SPM) in the Columbia River estuary system to determine the contribution of biological activity in lateral bays to the greater nutrient cycle of the river. Water samples were collected during neap and spring tidal forcing (25...
Experiments were conducted with two strains of the coccolithophorid Emiliania huxleyi. Previous experiments with CCMP1742 and 372 at a light intensity of 60 µEin/m²-s showed that during five-day periods of continuous darkness, strain 1742 was taking up nitrate from the media while strain 372 was not. The nitrate uptake in...
A three-part study was conducted into the impact of physiological and ecological variables on the net isotopic fractionation of hydrogen, α[subscript K₃₇], expressed in C₃₇ alkenones. First, alkenone-producer production, abundance, and export were characterized in the summertime Gulf of California and Eastern Tropical North Pacific using compound-specific, labeled in situ...
Suspended particulate matter (SPM) in the Columbia River is a mixture of particles of several origins having varying physical and biogeochemical properties. The relative abundances of these freshwater particles changes with season and apparently also with tide. Prior investigation has quantified seasonal variation of organic material in both the Columbia...
This study aims to improve knowledge of how suspended particulate matter (SPM) affects hydrophobic contaminant transport in the lower Columbia River and its estuary, using polycyclic aromatic hydrocarbons (PAHs) as model compounds. It is hypothesized that PAHs are transported to the estuarine turbidity maximum (ETM), a prime feeding zone in...
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Fredrick G. Prahl
This study aims to improve knowledge of how suspended particulate matter
The organic content of the Columbia River suspended particulate matter (SPM) results from the input of autochthonous (phytoplankton) and allochthonous (terrestrial vascular plants) production. The contribution of these two sources appears seasonal and responds to factors such as rainfall, runoff, river flow, light and nutrients availability. While numerous studies have...
A systematic study of highly branched isoprenoids (HBI) was carried out in
suspended particulate material (SPM) and Washington coastal sediments to determine
their origin and fate. SPM collected at 10 m depth was filtered through Nitex
membranes. C₂₅ HBI were found only in the 1.2-40 μm range over the shelf....
