Nutrient mass balance of a large riverine reservoir in the context of water residence time variability

Abstract This paper investigates the role of intervening transport processes on lake sediment records of the atmospherically deposited radionuclides 210Pb and 137Cs. Brotherswater is of particular interest to this issue in that its large catchment/lake area ratio and short water residence time are likely to amplify the influence of these processes, both from the catchment and through the water column. Brotherswater is also unique in being the site of two earlier multicore studies that, together with the present study, span a period of 4 decades. Measurements of fallout radionuclides were made on soil cores, suspended sediments and sediment cores, and the results combined with those from earlier studies to construct mass balances for 210Pb and 137Cs in Brotherswater. The results showed that catchment inputs accounted for 63% of 210Pb entering the lake. Further, just 47% of 210Pb entering the water column was delivered to the sediment record. For comparison, in an earlier study at nearby Blelham Tarn with a relatively smaller catchment but longer water residence time it was shown that 47% of 210Pb inputs were delivered via the catchment, 75% of which were delivered to the sediment record. Results from both sites suggest that 210Pb is predominantly transported on fine particulates with a mean particle size of 3–4 μm. Their relatively slow removal from the water column allows them to be transported relatively uniformly throughout the lake and may help account for the fact that simple 210Pb dating models are relatively reliable in spite of the complexities of the transport processes. Mass balance calculations for 137Cs are more complicated because of the variable fallout record. Measurements of 137Cs in the input stream and water column showed that catchment inputs are still significant 30 years after the last significant fallout (Chernobyl). Modelled results showed that catchment inputs delayed the date of peak inputs of weapons test fallout to the lake though by no more than 2 years. Although the results presented here are primarily concerned with fallout radionuclides and their reliability for dating, they also have implications for the use of sediment archives in reconstructing historical records of other atmospherically deposited substances such as trace metals or persistent organic pollutants.

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Integrating isotope mass balance and water residence time dating: insights of runoff generation in small permafrost watersheds from stable and radioactive isotopes

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-020-07315-1 ◽

2020 ◽

Vol 326 (1) ◽

pp. 241-254

Author(s):

Chengwei Wan ◽

Kai Li ◽

Huili Zhang ◽

Zhongbo Yu ◽

Peng Yi ◽

...

Keyword(s):

Mass Balance ◽

Residence Time ◽

Radioactive Isotopes ◽

Water Residence Time ◽

Runoff Generation ◽

Isotope Mass Balance

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Approximation of submarine groundwater discharge and allied nutrient fluxes to the Bay of Bengal, India using nutrient mass balance

Environmental Earth Sciences ◽

10.1007/s12665-021-09669-5 ◽

2021 ◽

Vol 80 (9) ◽

Author(s):

R. Prakash ◽

K. Srinivasamoorthy ◽

S. Gopinath ◽

K. Saravanan ◽

F. Vinnarasi

Keyword(s):

Mass Balance ◽

Bay Of Bengal ◽

Submarine Groundwater Discharge ◽

Groundwater Discharge ◽

Nutrient Fluxes ◽

Submarine Groundwater ◽

Nutrient Mass Balance

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Inter-tablet coating variability: Tablet residence time variability

Chemical Engineering Science ◽

10.1016/j.ces.2009.02.037 ◽

2009 ◽

Vol 64 (11) ◽

pp. 2705-2717 ◽

Cited By ~ 58

Author(s):

Arjun Kalbag ◽

Carl Wassgren

Keyword(s):

Residence Time ◽

Time Variability ◽

Tablet Coating

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Modelling nutrient mass balance in a temperate meso-tidal estuary: Implications for management

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2007.06.013 ◽

2008 ◽

Vol 76 (1) ◽

pp. 175-185 ◽

Cited By ~ 34

Author(s):

João Magalhães Neto ◽

Mogens René Flindt ◽

João Carlos Marques ◽

Miguel Ângelo Pardal

Keyword(s):

Mass Balance ◽

Tidal Estuary ◽

Nutrient Mass Balance

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Mapping and Assessing Commercial Fisheries Services in the Lithuanian Part of the Curonian Lagoon

Fishes ◽

10.3390/fishes7010019 ◽

2022 ◽

Vol 7 (1) ◽

pp. 19

Author(s):

Edgaras Ivanauskas ◽

Andrius Skersonas ◽

Vaidotas Andrašūnas ◽

Soukaina Elyaagoubi ◽

Artūras Razinkovas-Baziukas

Keyword(s):

Spatial Distribution ◽

Residence Time ◽

Fish Species ◽

Circulation Model ◽

Curonian Lagoon ◽

Water Residence Time ◽

Total Catch ◽

Catch Per Unit Effort ◽

Commercial Fish ◽

The Impact

The spatial distribution of biomass of main commercial fish species was mapped to estimate the supply of a provisioning fishery service in the Curonian lagoon. Catch per unit effort (CPUE) was used as a proxy to estimate the efficiency of commercial fishing and, subsequently, the potential biomass of fishes. The relationship between distinctive characteristics of the fishing areas and corresponding commercial catches and CPUE was analyzed using multivariate analysis. The total catch values and CPUE used in the analyses were derived from the official commercial fishery records. RDE analysis was used to assess the variation of both catch and CPUE of commercial fish species, while the percentages of bottom sediment type coverage, average depth, annual salinity, and water residence time in each of the fishing squares were used as explanatory variables. This distance e-based redundancy analysis allowed for the use of non-Euclidean dissimilarity indices. Fisheries data spatial distribution map indicated the lack of coherence between the spatial patterns of commercial catches and CPUE distribution in the northern part of the lagoon. Highest CPUE values were estimated in the central-eastern part of the lagoon as compared to the western part of the lagoon where CPUE values were substantially lower. Both total catch and CPUE appeared not to be related to the type of bottom habitats statistically while being spatially correlated in-between. However, the impact of salinity and water residence time calculated using the 3D hydraulic circulation model on the distribution of both CPUE and commercial catches was statistically significant.

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Can reductions in water residence time be used to disrupt seasonal stratification and control internal loading in a eutrophic monomictic lake?

Journal of Environmental Management ◽

10.1016/j.jenvman.2021.114169 ◽

2022 ◽

Vol 304 ◽

pp. 114169

Author(s):

Freya Olsson ◽

Eleanor B. Mackay ◽

Phil Barker ◽

Sian Davies ◽

Ruth Hall ◽

...

Keyword(s):

Residence Time ◽

Internal Loading ◽

Water Residence Time ◽

Seasonal Stratification ◽

And Control

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Coexisting ecosystem states in a tropical coastal lagoon under progressive eutrophication in the northern Cuban keys

Scientia Marina ◽

10.3989/scimar.04682.22a ◽

2018 ◽

Vol 82 (3) ◽

pp. 139 ◽

Cited By ~ 1

Author(s):

Roberto González-De Zayas ◽

Martin Merino-Ibarra ◽

Patricia M. Valdespino-Castillo ◽

Yunier Olivera ◽

Sergio F. Castillo-Sandoval

Keyword(s):

Residence Time ◽

Coastal Lagoon ◽

Spatial And Temporal Variability ◽

Positive Trend ◽

Water Residence Time ◽

Effective Management ◽

Management Options ◽

Trophic Index ◽

Tropical Coastal Lagoon ◽

Mollusc Assemblages

Through a nested suite of methods here we contrast the coexistence of different ecosystem states in a tropical coastal lagoon, the Laguna Larga, with increasing eutrophication stress between 2007 and 2009. Water temperature averaged 27.4°C in the lagoon and showed a slight positive trend during the study period. Salinity averaged 35.0±6.2, exhibiting high spatial and temporal variability, and also a slight positive trend in time. In contrast, dissolved oxygen showed a substantial decreasing trend (–0.83 ml L–1 y–1; –13.3% y–1) over the period, while nutrients increased dramatically, particularly total phosphorus (2.6 µM y–1), in both cases sustaining the progression of eutrophication in the lagoon during the three years we sampled. The Karydis nutrient load-based trophic index showed that the lagoon has a spatial pattern of increasing eutrophication from the sea and the outer sector (oligotrophic-mesotrophic) to the central (mesotrophic) and the inner sector (mesotrophic-eutrophic). Two ecosystem states were found within the lagoon. In the outer oligotrophic sector, the dominant primary producers were macroalgae, seagrasses and benthic diatoms, while mollusc assemblages were highly diverse. In the inner and central sectors (where trophic status increased toward the inner lagoon) a phytoplankton-dominated ecosystem was found where mollusc assemblages are less diverse. In spite of the progression of eutrophication in the lagoon, these two different ecosystems coexisted and remained unchanged during the study period. Apparently, the effect of water residence time, which increases dramatically toward the inner lagoon, dominated over that of nutrient loadings, which is relatively more homogeneously distributed along the lagoon. Therefore, we consider that actions that reduce the water residence time are likely the most effective management options for this and other similarly choked lagoons.

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