Most of the dissolved iron (Fe) in seawater is complexed by organic ligands. One key issue in understanding Fe limitation in the sea is the bioavailability of different forms of Fe to marine phytoplankton. We measured Fe uptake by the coastal diatom Thalassiosira pseudonana and the cyanobacterium Synechococcus sp., using model ligands desferrioxamine B (DFB) and ferrichrome (FC), humic acids (H...

The organic matter of soils is generally determined by converting it to carbon dioxide by means of moist and dry combustion. The carbon dioxide thus evolved is then calculated to organic matter by the use of a conventional factor, 0.471. It has been found, however, that the percentage of carbon in the organic matter of soils varies widely. Some doubt, therefore, is cast on the accuracy of the c...

We measured accumulation rates of organic carbon (OC) and total nitrogen (TN) and stable carbon (dCorg) and nitrogen isotopes (d15N) in the sediments of two mountain lakes (Lake Ledvica and Lake Planina, northwest Slovenia). Marked variations of these parameters were observed in both sediments. OC accumulation rates ranged from 4 to 23 g m22 yr21 in Lake Ledvica, whereas in Lake Planina they we...

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...

Liquid chromatography-mass spectrometry using atmospheric pressure ionization is dramatically changing the analytical methods, potential and tasks of water analysis. The present status in applying this technique to organic as well as inorganic water constituents and its use in the context of wastewater treatment and drinking water preparation is reviewed. Separation techniques such as reversed-...

Accurate information on the chemical nature of soil phosphorus is essential for understanding its bioavailability and fate in wetland ecosystems. Solution phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy was used to assess the conventional colorimetric procedure for phosphorus speciation in alkaline extracts of organic soils from the Florida Everglades. Molybdate colorimetry mark...

For determining variation in mineral composition and phosphorus (P) profile among streams of dry-grind ethanol production, samples of ground corn, intermediate streams, and distillers dried grains with solubles (DDGS) were obtained from three commercial plants. Most attributes (dry matter concentrations) increased significantly from corn to cooked slurry but fermentation caused most significant...

Wastewater from the wood and pulp industry is of environmental concern. It contains high concentrations of organic and inorganic matter. In this work a combined method of coagulation, adsorption and nanofiltration/reverse osmosis (NF/RO) was investigated in the purification of biologically treated wastewater from wood processing. Coagulation with 0.8 g dm(-3) AlCl3 x 6H2O and adsorption on 2.5 ...

The role of dissolved organic matter (DOM) as either a sink for inorganic nutrients or an additional nutrient source is an often-neglected component of nutrient budgets in aquatic environments. Here, we examined the role of DOM in reactive nitrogen (N) storage in Sierra Nevada (California, USA) lakes where atmospheric deposition of N has shifted the lakes toward seasonal phosphorus (P)-limitati...