Measured and modelled effects of temperature, dissolved oxygen and nutrient concentration on sediment-water nutrient exchange

Abstract

Empirical models of sediment-water fluxes of NH, + , NO3 -and POa3 -were formed based on published reports. The models were revised and parameters evaluated based on laboratory incubations of sediments collected from Gunston Cove, VA. Observed fluxes ranged from -18 (sediment uptake) to 276 (sediment release) mg NH,+ me2 day-', -17 to -509mgNO,-mp2dayy1, and -16.4 to 8.9 mg POd3-me2 day-'. The model and observations indicated release of NH,+ was enhanced by high temperature and by low DO. Uptake of NO, -was enhanced primarily by high NO, -concentration and to a lesser extent by high temperature and by low DO. Direction of POa3-flux depended on concentration in the water. Release was enhanced by low DO. No effect of temperature on POA3 -flux was observed.

Seasonal variability in phosphorus concentrations in strongly eutrophic Lake Chełmżyńskie

“…In 2007 and 2008 a deoxygenated zone appeared in the near-bottom layer at he stands 1 and 2. In such conditions the decomposition of iron-phosphorus complex and the release of phosphates to the near-bottom water occur (Cerco 1989). As early as in May the concentrations of phosphates and total phosphorus in the near-bottom layer were higher than the concentrations of phosphorus compounds in the surface layer.…”

“…Wiśniewski 1995). Anoxic conditions found in the deposits and near-bottom water layer also contribute to the release of phosphates (Cerco 1989). The process of phosphorus release in the water is also determined by the reaction, temperature and type of compounds in which it occurs as well as deposits structure (Kentzer 2001;R.J.…”

The influence of a long-term artificial aeration on the nitrogen compounds exchange between bottom sediments and water in Lake Długie

“…High temperature in the near-bottom water accelerates mineralization processes of organic matter, especially the microbially driven transformations of nitrogen compounds (Cerco 1989, Gelda et al 2000. The lake's restoration with the destratification method caused a very high decrease of the ammonium and total nitrogen in the aerated station 2 (by approx.…”

“…Many authors (Cerco 1989;Rysgaard et al 1994;Tomaszek, Gruca-Rokosz 2004) report that even in aerobic near-bottom waters is possible the formation of so-called anaerobic micro-niches in the upper sediment layer where denitrification may occur. The high contents of organic matter in the bottom sediments of Lake Długie (30-50% d.w. -Brzozowska, Gawrońska 2006) and improvement of the aerobic conditions near the bottom during the aeration undoubtedly favoured intensification of the nitrification-denitrification processes in the lake.…”

Sakaryabaşı Batı Göletinin Ötrofikasyon Derecesinin Araştırılması

“…Sedimentten amonyumun sal ı n ı m ı , yüksek s ı cakl ı k ve dü ş ük çözünmü ş oksijen durumunda artarken, fosfat sal ı n ı m ı n ı n dü ş ük çözünmü ş oksijen değ erlerinde yükseldi ğ i, bu olaya s ı cakl ığı n bir etkisi olmad ığı tespit edilmi ştir (Cerco 1989). …”