Internal nutrient flux in an inland water supply reservoir, New South Wales, Australia

Abstract

Nutrient dynamics at the water-sediment interface in the Suma Park Reservoir, Australia, was assessed under simulated laboratory conditions using intact sediment cores. This laboratory experiment demonstrated that the nutrient influx between the sediment and the water column, in both oxic and anoxic environments, contributed substantially to the total nutrient budget and overall recycling of the biologically available nutrients in the reservoir. This study also confirmed that the bottom sediments act as a source of ammonium-nitrogen (NH 4 -N) and filterable reactive phosphorus (FRP), but function as a sink for nitrate-nitrogen (NO 3 -N). Extrapolation of the experiment data revealed that the highest nutrient flux was obtained under a summer-anoxic incubation, with the internal loads of FRP and NH 4 -N accounting for ≈ 365% and 338% of their external annual loads, respectively. The internal loss of NO 3 -N from the summer anoxic incubation was ≈ 7% of its external annual load. The temperature and dissolved oxygen concentration were the most important factors influencing the nutrient flux and internal loading. Denitrification was believed to be an eminent route of nitrate loss from the reservoir.

Limnological characteristics and trophic state of Paso de las Piedras Reservoir: An inland reservoir in Argentina

“…This could indicate the phosphorus inflow into the water column is more closely related to phosphorus remobilization from the bottom sediments than from an external input, so that the phosphorus dynamics would not be as readily influenced by environmental factors than the nitrogen dynamics. It has been pointed out by numerous authors that sediments can act both as a source and as a storage of nutrients into lakes and reservoirs, and that recycling the same interface in the sediment–water plays a critical role in the development of eutrophication, and in establishing algae blooms which, in turn would be strongly influenced by physical factors such as water temperature and renewal (Ryding & Rast 1992; Al Bakri & Chowdhury 2006).…”

Factors influencing release of phosphorus from sediments in a high productive polymictic lake system

“…Therefore it seems likely that release of NH 4 -N and P from bottom sediments depend on decomposition of OM. Nedwell (1984) and Al Bakri & Chowdhury (2006) had also reported that sediment NH 4 -N release rate is a function of mineralization induced by warm temperatures. Given the magnitude of macrophyte biomass (3.2 kg/m 2 ) and organic enrichment in the lake (Table 2), photosynthetically elevated pH and mineralization of organic matter are directly influenced by temperature.…”

Enrichment and geoaccumulation of metals in the superficial sediments of Lake Chivero, Zimbabwe

“…When metals enter an aquatic ecosystem, they can be adsorbed to particulate matter and be removed from the water column to the bottom sediments (Alyazichi et al, ; Ledo et al, ). Sediments can act as a sink, being an integrator and amplifier for metals in rivers, lakes and reservoirs (Al Bakri & Chowdhury, ). Thus, the quality of sediments has been recognized as an important indicator of aquatic pollution (Chabukdhara & Nema, ).…”

“…Thus, the quality of sediments has been recognized as an important indicator of aquatic pollution (Chabukdhara & Nema, ). Although most adsorbed pollutants on sediments might not be readily available for aquatic organisms, factors such as pH, salinity, dissolved oxygen (DO), redox potential, nitrates (NO 3 ), microbial activities and organic content of the overlying water could induce the release of metals back into the aqueous phase (Al Bakri & Chowdhury, ; Idris, ). This can result in elevated metal concentration levels in the water, which can be toxic to aquatic organisms and a challenge to human consumption of this resource (Amin, Ismail, Arshad, Yap, & Kamarudin, ).…”