Variation in water residence time is the primary determinant of phytoplankton and zooplankton composition in a Pacific Northwest reservoir ecosystem (Lower Snake River, USA)

River Systems ◽  
2015 ◽  
Vol 21 (4) ◽  
pp. 241-255 ◽  
Author(s):  
John R. Beaver ◽  
Kyle C. Scotese ◽  
Erin E. Manis ◽  
Steve T.J. Juul ◽  
Joe Carroll ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Residence Time ◽  
Snake River ◽  
Water Residence Time ◽  
Primary Determinant

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

Fishes ◽  
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.

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

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

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

2018 ◽  
Vol 82 (3) ◽  
pp. 139 ◽  
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.

Understanding Grain Movements for Demand Estimation

2005 ◽  
Vol 1909 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Eric Jessup ◽  
Ken Casavant
Keyword(s):  
Pacific Northwest ◽  
Stated Preference ◽  
Transportation Network ◽  
Snake River ◽  
Revealed Preferences ◽  
Empirical Estimation ◽  
Demand Models ◽  
Volume Response ◽  
Grain Marketing ◽  
Discrete Choice Demand

Grain producers and handlers in Washington State have benefited from a multimodal transportation network of roads, railroads, and the Columbia–Snake River barge system to move large amounts of grain effectively in a timely and economic manner. The competitive environment of the grain industry brings many changes, including the number of firms and houses, mergers, and modal competitiveness. Additionally, marketing strategies are affected because choices of available transportation modes reflect the decision processes of warehouses or firm managers. This aggregate study of grain marketing and transportation in the Pacific Northwest helps lay the groundwork for subsequent estimates of empirical demand. Such subsequent modeling attempts may include revealed and stated preference analysis in discrete choice demand models. A thorough understanding of the industry and market characteristics should improve empirical estimation efforts and produce more defensible policy analysis. Based on a 90% shipment volume response rate, results show that in the Columbia–Snake River grain situation, one destination absorbs more than 90% of shipments. Modal competition is active; barge has a market share of more than 50%, down 12–16% from 10 years ago. Multiple-car shipments have increased, but not drastically. Rates are consistently competitive over the period. Finally, grain demand is seasonal but generally has been stable over time. The revealed preferences from this aggregate analysis suggest that price elasticity may vary across shippers, times of movement, and modal availability.

scholarly journals Calanoid copepod zooplankton density is positively associated with water residence time across the continental United States

PLoS ONE ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. e0209567 ◽  
Author(s):  
Jonathan P. Doubek ◽  
Cayelan C. Carey ◽  
Michael Lavender ◽  
Amanda K. Winegardner ◽  
Marieke Beaulieu ◽  
...  
Keyword(s):  
United States ◽  
Residence Time ◽  
Calanoid Copepod ◽  
Water Residence Time ◽  
Zooplankton Density

scholarly journals Variability of water residence time and free chlorine and disinfection by-product concentrations within a residential neighborhood

2017 ◽  
Vol 66 (4) ◽  
pp. 219-228 ◽  
Author(s):  
Simon Rochette ◽  
Geneviève Pelletier ◽  
Christian Bouchard ◽  
Manuel Rodriguez
Keyword(s):  
Residence Time ◽  
Free Chlorine ◽  
Water Residence Time ◽  
Residential Neighborhood

scholarly journals Water residence time in Chesapeake Bay for 1980–2012

2016 ◽  
Vol 164 ◽  
pp. 101-111 ◽  
Author(s):  
Jiabi Du ◽  
Jian Shen
Keyword(s):  
Chesapeake Bay ◽  
Residence Time ◽  
Water Residence Time
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