Seston Ecology of the Surface Waters of Hudson Bay

1980 ◽  
Vol 37 (12) ◽  
pp. 2242-2253 ◽  
Author(s):  
J. T. Anderson ◽  
J. C. Roff
Keyword(s):  
Organic Carbon ◽  
Chlorophyll A ◽  
Surface Waters ◽  
Nitrogen Limitation ◽  
Grazing Pressure ◽  
Hudson Bay ◽  
Carbon And Nitrogen ◽  
First Time ◽  
Temperature Depth ◽  
Carbon:Nitrogen Ratios

The planktonic biomass variables, chlorophyll a, ATP, particulate organic carbon, and nitrogen have been measured in surface waters throughout Hudson Bay for the first time. On the basis of these variables Hudson Bay can be regarded as oligotrophc during the summer months. Clear inshore–offshore gradients of biomass were evident showing significant correlations in transects to salinity, temperature, depth, and distance from shore. Chlorophyll a values were always low, averaging 0.09 mg m−3 offshore and 0.28 mg m−3 inshore. ATP averaged 0.072 mg m−3 offshore and twice as high inshore. Biomass ratios also demonstrated clear inshore–offshore gradients; carbon:nitrogen ratios ranged from 4.9:1 inshore to 12.5:1 offshore indicating nitrogen limitation of offshore waters. Chlorophyll a: phaeopigment ratios decreased and biocarbon:chlorophyll a ratios increased offshore indicating an increased proportion of heterotrophs and possibly higher relative grazing pressure offshore. For the inshore areas, biomass and probably productivity were highest and significantly correlated to runoff with the exception of the Southampton–Coats–Mansel islands area, which is influenced by waters from Foxe Channel and Hudson Strait. While Hudson Bay meets most of the criteria for arctic classification, its character is sufficiently different to warrant special status.Key words: Hudson Bay, seston ecology, chlorophyll a, biomass ratios, phaeopigments, plankton

scholarly journals Spatial distribution and offshore export of total organic carbon along the eastern boundary of the Subtropical North Pacific

2011 ◽  
Vol 2 (2) ◽  
pp. 93
Author(s):  
C.G. Castro ◽  
C.A. Collins ◽  
J.T. Pennington ◽  
D. Zúñiga ◽  
F.P. Chavez
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Surface Waters ◽  
Average Rate ◽  
California Current ◽  
Early Summer ◽  
Ekman Transport ◽  
Minimum Zone ◽  
Production Increase ◽  
First Time

Data collected in February, 2003, along the upper continental slope of western North America between Monterey Bay, California (37°N, 122°W), and Cabo San Lucas, Mexico (23°N, 118°W), document, for the first time, the alongshore distribution of total organic carbon (TOC). Highest TOC concentrations (>70 µM) were observed for waters above the nitracline and associated with both California Current and southern surface waters. The northward advection of tropical waters in the California Undercurrent did not have any discernible impact on TOC distributions. An estimate of the average rate at which TOC in surface waters was exported offshore by Ekman transport in February 2003 was 1.73 × 103 kg C yr−1 for each meter of coastline. The offshore flux estimate is thought to be conservative with respect to the annual mean offshore flux because the offshore Ekman transport and primary production increase in late spring and early summer and the contribution of upwelling filaments has not been considered. Analysis of TOC contributions to pelagic respiration suggested that TOC accounted for 45% of the oxygen decrease in southern oxic waters. In California Current and oxygen minimum zone waters, TOC did not contribute to pelagic respiration.

Stabilization of Organic Carbon and Nitrogen in Consolidating Benthal Deposits

1985 ◽  
Vol 17 (6-7) ◽  
pp. 929-940 ◽  
Author(s):  
C. W. Bryant ◽  
L. G. Rich
Keyword(s):  
Organic Carbon ◽  
Model Verification ◽  
Volatile Acid ◽  
Free Energies ◽  
Organic Loading ◽  
Carbon And Nitrogen ◽  
Loading Rates ◽  
Degradation Reactions ◽  
The Individual ◽  
Organic Deposits

The objective of this research was to develop and validate a predictive model of the benthal stabilization of organic carbon and nitrogen in deposits of waste activated sludge solids formed at the bottom of an aerated water column, under conditions of continual deposition. A benthal model was developed from a one-dimensional, generalized transport equation and a set of first-order biological reactions. For model verification, depth profiles of the major interstitial carbon and nitrogen components were measured from a set of deposits formed in the laboratory at 20°C and a controlled loading rate. The observed sequence of volatile acid utilization in each benthal deposit was that which would be predicted by the Gibbs free energies of the individual degradation reactions and would be controlled by the reduction in interstitial hydrogen partial pressure with time. Biodegradable solids were solubilized rapidly during the first three weeks of benthal retention, but subsequent solubilization occurred much more slowly. The benthal simulation effectively predicted the dynamics of consolidating, organic deposits. Simulation of organic loading rates up to 250 g BVSS/(m2 day) indicated that the stabilization capacity of benthal deposits was far above the range of organic loading rates currently used in lagoon design.

Soil Organic Carbon and Nitrogen Variations with Vegetation Succession in Passively Restored Freshwater Wetlands

Wetlands ◽  
2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Yu An ◽  
Yang Gao ◽  
Xiaohui Liu ◽  
Shouzheng Tong ◽  
Bo Liu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Vegetation Succession ◽  
Freshwater Wetlands ◽  
Carbon And Nitrogen

scholarly journals Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1409
Author(s):  
Hamdhani Hamdhani ◽  
Drew E. Eppehimer ◽  
David Walker ◽  
Michael T. Bogan
Keyword(s):  
Chlorophyll A ◽  
Surface Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Water Quality Monitoring ◽  
Ambient Light ◽  
Calibration Equation ◽  
Field Samples ◽  
Potential Use

Chlorophyll-a measurements are an important factor in the water quality monitoring of surface waters, especially for determining the trophic status and ecosystem management. However, a collection of field samples for extractive analysis in a laboratory may not fully represent the field conditions. Handheld fluorometers that can measure chlorophyll-a in situ are available, but their performance in waters with a variety of potential light-interfering substances has not yet been tested. We tested a handheld fluorometer for sensitivity to ambient light and turbidity and compared these findings with EPA Method 445.0 using water samples obtained from two urban lakes in Tucson, Arizona, USA. Our results suggested that the probe was not sensitive to ambient light and performed well at low chlorophyll-a concentrations (<25 µg/L) across a range of turbidity levels (50–70 NTU). However, the performance was lower when the chlorophyll-a concentrations were >25 µg/L and turbidity levels were <50 NTU. To account for this discrepancy, we developed a calibration equation to use for this handheld fluorometer when field monitoring for potential harmful algal blooms in water bodies.

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