Role of Internal Phosphorus Loading in Two Shallow, Productive Lakes in Alberta, Canada

1984 ◽  
Vol 41 (6) ◽  
pp. 845-855 ◽  
Author(s):  
E. T. Riley ◽  
E. E. Prepas
Keyword(s):  
Surface Water ◽  
Deep Water ◽  
Laboratory Experiments ◽  
Water Exchange ◽  
Sediment Cores ◽  
Internal Loading ◽  
Phosphorus Loading ◽  
Quantitative Estimates ◽  
Internal Phosphorus Loading

The contribution of internal loading from the sediments to the total phosphorus (TP) budget and to the [TP] in the surface water was investigated from May to November in Nakamun and Halfmoon lakes, Alberta. During the summer, Nakamun Lake was intermittently stratified and Halfmoon Lake was weakly, thermally stratified. During the stratified periods, water overlying the sediments was anoxic, TP levels increased in the deep water, and sediments were the main source of TP, contributing 1468 and 147 kg of TP to Nakamun and Halfmoon lakes, respectively. During these same periods, internal loading to Nakamun and Halfmoon lakes (12.7 and 15.6 mg∙m−2∙d−1, respectively) were slightly higher than the rates predicted from laboratory experiments on sediment cores (9.7 and 7.2 mg∙m−2∙d−1, respectively). Quantitative estimates of vertical water exchange in Nakamun Lake and in-lake TP budgets for both lakes indicated that phosphorus released from the sediments was transported to the surface water during mixing. After eight of the nine mixing events that immediatley followed stratified periods, [TP] increased 3–43% and 31–52% in the surf ace water of Nakamun and Halfmoon lakes, respectively.

Effects of Fe addition on sediment P dynamics in a eutrophic lake

2021 ◽  
Author(s):  
Melanie Münch ◽  
Rianne van Kaam ◽  
Karel As ◽  
Stefan Peiffer ◽  
Gerard ter Heerdt ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Surface Water ◽  
Water Column ◽  
Sediment Cores ◽  
Surface Water Quality ◽  
Water Interface ◽  
Eutrophic Lakes ◽  
Fe Addition

<p>The decline of surface water quality due to excess phosphorus (P) input is a global problem of increasing urgency. Finding sustainable measures to restore the surface water quality of eutrophic lakes with respect to P, other than by decreasing P inputs, remains a challenge. The addition of iron (Fe) salts has been shown to be effective in removing dissolved phosphate from the water column of eutrophic lakes. However, the resulting changes in biogeochemical processes in sediments as well as the long-term effects of Fe additions on P dynamics in both sediments and the water column are not well understood.</p><p>In this study, we assess the impact of past Fe additions on the sediment P biogeochemistry of Lake Terra Nova, a well-mixed shallow peat lake in the Netherlands. The Fe-treatment in 2010 efficiently reduced P release from the sediments to the surface waters for 6 years. Since then, the internal sediment P source in the lake has been increasing again with a growing trend over the years.</p><p>In 2020, we sampled sediments at three locations in Terra Nova, of which one received two times more Fe during treatment than the other two. Sediment cores from all sites were sectioned under oxygen-free conditions. Both the porewaters and sediments were analysed for their chemical composition, with sequential extractions providing insight into the sediment forms of P and Fe. Additional sediment cores were incubated under oxic and anoxic conditions and the respective fluxes of P and Fe across the sediment water interface were measured.</p><p>The results suggest that Fe and P dynamics in the lake sediments are strongly coupled. We also find that the P dynamics are sensitive to the amount of Fe supplied, even though enhanced burial of P in the sediment was not detected. The results of the sequential extraction procedure for P, which distinguishes P associated with humic acids and Fe oxides, as well as reduced flux of Fe(II) across the sediment water interface in the anoxic incubations, suggest a major role of organic matter in the interaction of Fe and P in these sediments.</p><p>Further research will include investigations of the role of organic matter and sulphur in determining the success of Fe-treatment in sequestering P in lake sediments. Based on these data in combination with reactive transport modelling we aim to constrain conditions for successful lake restoration through Fe addition.</p>

Internal phosphorus loading from bottom sediments of a shallow preliminary reservoir

2008 ◽  
Vol 37 (2) ◽  
Author(s):  
Renata Dondajewska
Keyword(s):  
Bottom Sediments ◽  
Seasonal Variability ◽  
Sediment Cores ◽  
Phosphorus Release ◽  
Ex Situ ◽  
Phosphorus Loading ◽  
Internal Phosphorus Loading

Internal phosphorus loading from bottom sediments of a shallow preliminary reservoirThe aim of the studies done in a shallow preliminary reservoir (western Poland) was to determine the intensity and seasonal variability of phosphorus release from bottom sediments. Ex situ studies were done using intact sediment cores taken in succeeding seasons at 3 research stations. The highest phosphorus loading was observed in spring (May and April), both in 2005 and 2006. The range of loading was between 23.7 and 66.6 mgP m

scholarly journals On Natural Modulational Bandwidth of Deep-Water Surface Waves

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 67
Author(s):  
Alexander Babanin ◽  
Miguel Onorato ◽  
Luigi Cavaleri
Keyword(s):  
Deep Water ◽  
Water Surface ◽  
Laboratory Experiments ◽  
Wind Wave ◽  
Wave Spectra ◽  
Field Observations ◽  
Wave Steepness ◽  
Side Band ◽  
Wave Trains

We suggest that there exists a natural bandwidth of wave trains, including trains of wind-generated waves with a continuous spectrum, determined by their steepness. Based on laboratory experiments with monochromatic waves, we show that, if no side-band perturbations are imposed, the ratio between the wave steepness and bandwidth is restricted to certain limits. These limits are consistent with field observations of narrow-banded wind-wave spectra if a characteristic width of the spectral peak and average steepness are used. The role of the wind in such modulation is also discussed.

The Role of Ocean Tides on Groundwater-Surface Water Exchange in a Mangrove-Dominated Estuary: Shark River Slough, Florida Coastal Everglades, USA

2016 ◽  
Vol 39 (6) ◽  
pp. 1600-1616 ◽  
Author(s):  
Christopher G. Smith ◽  
René M. Price ◽  
Peter W. Swarzenski ◽  
Jeremy C. Stalker
Keyword(s):  
Surface Water ◽  
Water Exchange ◽  
Ocean Tides

Role of wetlands in reducing phosphorus loading to surface water in eight watersheds in the Lake Champlain Basin

1996 ◽  
Vol 20 (5) ◽  
pp. 731-739 ◽  
Author(s):  
Christine M. Weller ◽  
Mary C. Watzin ◽  
Deane Wang
Keyword(s):  
Surface Water ◽  
Phosphorus Loading ◽  
Lake Champlain

scholarly journals Antarctic Thermocline Dynamics along a Narrow Shelf with Easterly Winds

2018 ◽  
Vol 48 (10) ◽  
pp. 2419-2443 ◽  
Author(s):  
Tore Hattermann
Keyword(s):  
Surface Water ◽  
Deep Water ◽  
Shelf Break ◽  
Weddell Sea ◽  
Thermocline Depth ◽  
Intermediate Water ◽  
Boundary Current ◽  
Warm Deep Water ◽  
The Antarctic

AbstractDetermining the role of Southern Ocean warm intermediate water for driving melting of the Antarctic ice sheet is a major challenge in assessing future sea level rise. Analysis of 2859 CTD profiles obtained between 1977 and 2016 by ships and instrumented seals at the Weddell Sea continental slope reveals a seasonal rise of the Antarctic Slope Front thermocline by more than 100 m during the summer. The signal at Kapp Norvegia (17°W) corresponds with a seasonal warming downstream at the Filchner Trough (40°W), indicating that a coherent evolution of the slope front along the shelf break regulates the onshore flow of warm deep water. Climatological cross sections of the slope front hydrography show that downwelling of Antarctic Surface Water forms a secondary front above the warm deep water interface during summer. Enhanced baroclinic growth rates at this front suggest that the wind-driven suppression of the thermocline is partially compensated by a shallower eddy overturning cell when surface water is present. A simple model of the Weddell Gyre boundary current reveals that wintertime densification of surface waters is crucial for maintaining the deep thermocline along the eastern Weddell Sea coast. The sensitivity of the warm inflow to the cross-frontal density gradient implies a positive feedback with ice shelf melting that may lead to an abrupt transition into a high melting state once warm water rises over the shelf break depth. Despite its regional focus, this study highlights the role of upper ocean buoyancy fluxes for controlling the thermocline depth along seasonally ice-covered narrow shelf regions with cyclonic along-slope winds.

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