Reservoir thermal stratification drives the water temperature and dissolved oxygen gradient, however, the characteristic of vertical water microbial community during thermal stratification is so far poorly understood. In this work, water bacterial community diversity was determined using the Illumina Miseq sequencing technique. The results showed that epilimnion, metalimnion and hypolimnion wer...

A probe inlet for membrane-inlet mass spectrometry (MIMS) was developed to measure dissolved nitrogen and argon gas in sediment porewaters. This technique represents a significant improvement in the measurement of dissolved gas ratios in sediment cores and in small volume samples ( < 5 ml). The probe is stable, inexpensive and has relatively fast equilibration times (f 4–5 min) for dissolved N2...

Nitrate uptake in the epilemnetic waters of a small eutrophic Canadian Shield lake was studied by using a 15N method during summer stratification. Concurrent with inhibition of primary production, 3-(3,4-dichlorophenyl)-1,1-dimethylurea inhibited NO3- assimilation. Nitrate up to 1 mg of N/liter did not affect the rate of primary production during 3 h of incubation. The NO3- fertilizer added to ...

For up to 18 yr we monitored salinity and the concentrations of nutrients, organic matter, plant pigments, and suspended particles in the Rhode River (a subestuary of Chesapeake Bay, USA) to examine long-term trends and relabonships to watershed discharges. There was no clear evldence of increasing eutrophlcation. Chlorophyll concentration did not show a long-term trend, although pheopigments i...

Dissolved organic nitrogen (DON) derived from wastewater effluent can participate in reactions that lead to formation of nitrogenous chlorination by-products, membrane fouling, eutrophication, and nitrification issues, so management of DON is important for both wastewater reuse applications and nutrient-sensitive watersheds that receive discharges from treated wastewater. This study documents D...

Interactions between oceanic nitrate ecology and circulation determine the marine distribution of dissolved, climate relevant trace gases such as dimethyl sul®de (DMS) and carbonyl sul®de (OCS), and a variety of hydrocarbons. Our group is constructing a suite of ecosystem/reaction/transport models, which link nitrate to the chemistry of volatiles near the sea±air interface. In this paper, we de...

Climate change is expected to bring about alterations in the marine physical and chemical environment that will induce changes in the concentration of dissolved CO(2) and in nutrient availability. These in turn are expected to affect the physiological performance of phytoplankton. In order to learn how phytoplankton respond to the predicted scenario of increased CO(2) and decreased nitrogen in ...

We organized a crowdsourcing experiment in the form of a snapshot sampling campaign to assess the spatial distribution of nitrogen solutes, namely, nitrate, ammonium and dissolved organic nitrogen (DON), in German surface waters. In particular, we investigated (i) whether crowdsourcing is a reasonable sampling method in hydrology and (ii) what the effects of population density, soil humus conte...

This study evaluated water quality of the Nissitissit River and Salmon Brook, located in southeastern New Hampshire and northeastern Massachusetts. Water samples were collected once a month over three consecutive months (June, July, and August – summer of 2007) at five locations in each river and analyzed for a group of chemical and microbiological parameters typically monitored to characterize...

the physico-chemical parameters, nutrient status and heavy metal ions of huluka and alaltu rivers of ambo, ethiopia were studied. temperature, ph, electrical conductivity, co2 content, total dissolved solids, hardness, dissolved oxygen, ca2+, mg2+, cl-, nitrate, phosphate and sulphate have been determined along with selected heavy metals to assess the various water quality profiles along the ri...