The relationship between dissolved organic carbon (DOC) and fluorescence in anoxic marine porewaters: Implications for estimating benthic DOC fluxes

1993 ◽  
Vol 57 (9) ◽  
pp. 2149-2153 ◽  
Author(s):  
Robert F. Chen ◽  
Jeffrey L. Bada ◽  
Yoshimi Suzuki
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
The Relationship

scholarly journals Proximate and ultimate controls on carbon and nutrient dynamics of small agricultural catchments

2016 ◽  
Vol 13 (6) ◽  
pp. 1863-1875 ◽  
Author(s):  
Zahra Thomas ◽  
Benjamin W. Abbott ◽  
Olivier Troccaz ◽  
Jacques Baudry ◽  
Gilles Pinay
Keyword(s):  
Water Quality ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Water Chemistry ◽  
Human Disturbance ◽  
Nutrient Dynamics ◽  
Agricultural Activity ◽  
Agricultural Catchments ◽  
The Impact ◽  
The Relationship

Abstract. Direct and indirect effects from human activity have dramatically increased nutrient loading to aquatic inland and estuarine ecosystems. Despite an abundance of studies investigating the impact of agricultural activity on water quality, our understanding of what determines the capacity of a watershed to remove or retain nutrients remains limited. The goal of this study was to identify proximate and ultimate controls on dissolved organic carbon and nutrient dynamics in small agricultural catchments by investigating the relationship between catchment characteristics, stream discharge, and water chemistry. We analyzed a 5-year, high-frequency water chemistry data set from three catchments in western France ranging from 2.3 to 10.8 km2. The relationship between hydrology and solute concentrations differed between the three catchments and was associated with hedgerow density, agricultural activity, and geology. The catchment with thicker soil and higher surface roughness had relatively invariant carbon and nutrient chemistry across hydrologic conditions, indicating high resilience to human disturbance. Conversely, the catchments with smoother, thinner soils responded to both intra- and interannual hydrologic variation with high concentrations of phosphate (PO43−) and ammonium (NH4+) in streams during low flow conditions and strong increases in dissolved organic carbon (DOC), sediment, and particulate organic matter during high flows. Despite contrasting agricultural activity between catchments, the physical context (geology, topography, and land-use configuration) appeared to be the most important determinant of catchment solute dynamics based on principle components analysis. The influence of geology and accompanying topographic and geomorphological factors on water quality was both direct and indirect because the distribution of agricultural activity in these catchments is largely a consequence of the geologic and topographic context. This link between inherent catchment buffering capacity and the probability of human disturbance provides a useful perspective for evaluating vulnerability of aquatic ecosystems and for managing systems to maintain agricultural production while minimizing leakage of nutrients.

scholarly journals Hydrological controls on DOC : nitrate resource stoichiometry in a lowland, agricultural catchment, southern UK

2017 ◽  
Author(s):  
Catherine M. Heppell ◽  
Andrew Binley ◽  
Mark Trimmer ◽  
Tegan Darch ◽  
Ashley Jones ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
River Water ◽  
Positive Relationship ◽  
Agricultural Landscapes ◽  
Lowland River ◽  
Significant Positive Relationship ◽  
Molar Ratios ◽  
The Relationship

Abstract. The role that hydrology plays in governing the interactions between dissolved organic carbon (DOC) and nitrogen in rivers draining lowland, agricultural landscapes is currently poorly understood, yet important to assess given the potential changes to production and delivery of DOC and nitrate arising from climate change. We measured DOC and nitrate concentrations in river water of six reaches of the lowland River Hampshire Avon (Wiltshire, southern UK) in order to quantify the relationship between Baseflow Index (BFI) and DOC : nitrate molar ratios across contrasting geologies (Chalk, Greensand and clay). We found a significant positive relationship between nitrate and Baseflow Index (p 

Relationship of Mercury Concentrations in Lake Trout (Salvelinus namaycush) and Smallmouth Bass (Micropterus dolomieui) to the Physical and Chemical Characteristics of Ontario Lakes

1989 ◽  
Vol 46 (3) ◽  
pp. 426-434 ◽  
Author(s):  
Michael J. McMurtry ◽  
Donna L. Wales ◽  
Wolfgang A. Scheider ◽  
Gail L. Beggs ◽  
Patricia E. Dimond
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Lake Trout ◽  
Water Hardness ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Stepwise Multiple Regression ◽  
Lake Area ◽  
Micropterus Dolomieui ◽  
The Relationship

Concentrations of mercury in dorsal muscle tissue of lake trout (Salvelinus namaycush) from Ontario lakes were positively correlated with variables indicating lake dystrophy (dissolved organic carbon, colour, iron, transparency) and were also correlated with watershed area and lake area. Stepwise multiple regression selected dissolved organic carbon as the only variable which explained a significant amount of variation (37%) in mercury concentrations in lake trout. The relationship between dissolved organic carbon and mercury appeared to be strongest in the group of lakes with values of dissolved organic carbon less than 4.0 mg∙L−1. In contrast, mercury concentrations in smallmouth bass (Micropterus dolomieui) were correlated with variables reflecting both water hardness (magnesium, calcium, conductivity) and acidity (pH, alkalinity). The relationship was inverse for the water hardness variables and positive for acidity. Stepwise regression identified three variables significant in explaining variation in mercury in smallmouth bass: calcium, dissolved organic carbon, and latitude. Mechanisms that may explain the effects of organic matter, water hardness, and acidity on mercury accumulation by fish are discussed.

scholarly journals Trade-offs Between Light and Nutrient Availability Across Gradients of Dissolved Organic Carbon Lead to Spatially and Temporally Variable Responses of Lake Phytoplankton Biomass to Browning

Ecosystems ◽  
2021 ◽  
Author(s):  
Peter D. F. Isles ◽  
Irena F. Creed ◽  
Anders Jonsson ◽  
Ann-Kristin Bergström
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Nutrient Availability ◽  
Phytoplankton Biomass ◽  
Light Availability ◽  
Nutrient Stoichiometry ◽  
Spatial Gradients ◽  
Trade Offs ◽  
Lower Light ◽  
The Relationship

AbstractNorthern lakes are experiencing widespread increases in dissolved organic carbon (DOC) that are likely to lead to changes in pelagic phytoplankton biomass. Pelagic phytoplankton biomass responds to trade-offs between light and nutrient availability. However, the influence of DOC light absorbing properties and carbon–nutrient stoichiometry on phytoplankton biomass across seasonal or spatial gradients has not been assessed. Here, we analyzed data from almost 5000 lakes to examine how the carbon–phytoplankton biomass relationship is influenced by seasonal changes in light availability, DOC light absorbing properties (carbon-specific visual absorbance, SVA420), and DOC–nutrient [total nitrogen (TN) and total phosphorus (TP)] stoichiometry, using TOC as a proxy for DOC. We found evidence for trade-offs between light and nutrient availability in the relationship between DOC and phytoplankton biomass [chlorophyll (chl)-a], with the shape of the relationship varying with season. A clear unimodal relationship was found only in the fall, particularly in the subsets of lakes with the highest TOC:TP. Observed trends of increasing TOC:TP and decreasing TOC:TN suggest that the effects of future browning will be contingent on future changes in carbon–nutrient stoichiometry. If browning continues, phytoplankton biomass will likely increase in most northern lakes, with increases of up to 76% for a 1.7 mg L−1 increase in DOC expected in subarctic regions, where DOC, SVA420, DOC:TN, and DOC:TP are all low. In boreal regions with higher DOC and higher SVA420, and thus lower light availability, lakes may experience only moderate increases or even decreases in phytoplankton biomass with future browning.

scholarly journals Temperature-dependence of the relationship between <i>p</i>CO<sub>2</sub> and dissolved organic carbon in lakes

2015 ◽  
Vol 12 (3) ◽  
pp. 2787-2808 ◽  
Author(s):  
L. Pinho ◽  
C. M. Duarte ◽  
H. Marotta ◽  
A. Enrich-Prast
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Carbon Cycling ◽  
Positive Relationship ◽  
Doc Concentration ◽  
The Tropics ◽  
Lake Waters ◽  
The Relationship ◽  
Latitudinal Range ◽  
Warm Lakes

Abstract. The relationship between the partial pressure of carbon dioxide (pCO2) and dissolved organic carbon (DOC) concentration in Brazilian lakes, encompassing 225 samples across a wide latitudinal range in the tropics, was tested. Unlike the positive relationship reported for lake waters, which was largely based on temperate lakes, we found no significant relationship for tropical and subtropical Brazilian lakes, despite very broad ranges in both pCO2 and DOC. Closer examination showed that the strength of pCO2 vs. DOC relationships declines with increasing water temperature, suggesting substantial differences in carbon cycling in warm lakes, which must be considered when upscaling limnetic carbon cycling to global scales.

Dissolved organic carbon and relationship with bacterioplankton community composition in 3 lake regions of Lake Taihu, China

2014 ◽  
Vol 60 (10) ◽  
pp. 669-680 ◽  
Author(s):  
Xinghong Pang ◽  
Hong Shen ◽  
Yuan Niu ◽  
Xiaoxue Sun ◽  
Jun Chen ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Community Composition ◽  
Lake Taihu ◽  
Eutrophic Lakes ◽  
Bacterioplankton Community ◽  
Doc Concentration ◽  
Lake Center ◽  
Meiliang Bay ◽  
The Relationship

To clarify the relationships between dissolved organic carbon (DOC) and bacterioplankton community composition (BCC), a 1-year survey (June 2009 – May 2010) was conducted in 3 regions of Lake Taihu (Meiliang Bay, Lake Center, and Eastern Taihu), China. Polymerase chain reaction – denaturing gradient gel electrophoresis was used to analyze the composition and heterogeneity of the bacterioplankton community. Canonical correspondence analysis was used to explore the relationships between DOC concentration and BCC. We found a significant negative correlation between DOC concentration and bacterioplankton community diversity (as measured by the Shannon–Wiener index (H′)). The results show that spatial variation in the bacterioplankton population was stronger than the seasonal variation and that DOC concentration influences BCC in Lake Taihu. DOC concentration, followed by macrophyte biomass, water turbidity, and phytoplankton biomass were the most influential factors that account for BCC changes in Lake Taihu. More detailed studies on the relationship between DOC concentration and BCC should focus on differences in DOC concentrations and quality among these lake regions. DOC had a significant impact on BCC in Meiliang Bay. The relationship between DOC and BCC in the 2 other regions studied (Lake Center and Eastern Taihu) was weaker. The results of this study add to our understanding of the BCC in eutrophic lakes, especially regarding the role of the microbial loop in lake ecosystems.

scholarly journals Influence of Dissolved Organic Matter Sources on In-Stream Net Dissolved Organic Carbon Uptake in a Mediterranean Stream

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1722 ◽  
Author(s):  
Anna Lupon ◽  
Núria Catalán ◽  
Eugènia Martí ◽  
Susana Bernal
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Dissolved Organic Carbon ◽  
Leaf Litter ◽  
Natural Conditions ◽  
Mediterranean Stream ◽  
Doc Concentration ◽  
The Relationship ◽  
Different Sources

Studies exploring how different sources of dissolved organic matter (DOM) influence in-stream dissolved organic carbon (DOC) uptake at the ecosystem scale are scarce in the literature. To fill this knowledge gap, we examined the relationship between DOM sources and in-stream net DOC uptake (UDOC) in a sub-humid Mediterranean stream. We considered four reach-scale scenarios occurring under natural conditions that differed in predominant DOM sources (groundwater, leaf litter, and/or upstream water). Results showed that groundwater inputs favored in-stream net DOC uptake, while leaf litter inputs promoted in-stream net DOC release. However, there was no clear effect of DOM source mixing on the magnitude of UDOC. Further, the variability in UDOC within and among scenarios was mostly explained by stream DOC concentration, suggesting that DOC availability limits microbial activity in this stream. DOM composition became a controlling factor of UDOC variability only during the leaf litter period, when stream DOC concentration was the highest. Together, these results suggest that the capacity of headwater forested streams to process DOC is closely tied to the availability of different DOM sources and how they vary over time and along the river network.

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