A cross-system analysis of labile dissolved organic carbon

Søndergaard, Morten; Middelboe, Mathias

doi:10.3354/meps118283

Cited by 296 publications

(233 citation statements)

References 63 publications

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“…Stepenauskas (1999) showed that bioavailability of DOM is enhanced after mixing of lake and ocean water. However, studying Cabiúnas lagoon (Northeast Brazil) that author showed that DOM of the ocean were more bioavailable than lake DOM, a result that corroborates previous cross-system comparisons (Søndergaard and Middelboe, 1995).…”

Section: The Functioning Process and Services Of Nclsupporting

confidence: 74%

Neotropical coastal lagoons: an appraisal of their biodiversity, functioning, threats and conservation management

et al. 2008

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Neotropical coastal lagoons (NCL) are human-dominated ecosystems. Their distribution along densely populated coastal areas of developing countries makes these systems among the most threatened in the world. Here, we summarize some aspects of the causes and consequences of NCL biodiversity, their functioning, their importance to the surrounding populations, their fragility, and their responses to local and global anthropogenic impacts and the challenges that Neotropical countries face in conserving these systems. Although still scarce and geographically concentrated, a growing body of studies has shown that NCLs are physiographically diversified systems, which harbor a considerable and particular proportion of the Neotropical inland aquatic biodiversity. Despite the fact that coastal lagoons are ecotones that are intricately connected to surrounding environments, they develop mechanisms for structural and functional regulation, which confer to these systems higher productivity and carrying capacities than surrounding ecosystems. Such traits attract residential developments and subsidize local traditional populations with important economic and aesthetic ecosystem revenues such as fisheries and scenic beauty. However, the disorganized human occupation around NCLs are causing profound impacts such as eutrophication, salinization, exotic species introduction, as well as other effects, which are ultimately imposing major habitat degradations and biodiversity extirpations in NCLs. We argue that interdisciplinary conservation strategies, which integrate scientific expertise, government officials, private companies and the general public, are the most likely to overcome the geographic and economic obstacles to NCL conservation.Keywords: coastal ecosystems, ecosystem management, shallow lakes, human impacts, tropical limnology.Lagoas costeiras neotropicais: Uma apreciação sobre sua biodiversidade, funcionamento, principais ameaças e estratégias de conservação ResumoAs lagoas costeiras neotropicais (LCN) estão inseridas em um ambiente antropogênico. Sua localização em regiões costeiras densamente povoadas de países em desenvolvimento coloca estes ecossistemas entre os mais impactados do mundo. Neste trabalho, resumimos vários aspectos relacionados às causas e conseqüências da sua biodiversidade, seu funcionamento e os bens proporcionados à população do seu entorno. Sua fragilidade e as respostas a impactos humanos locais e globais, assim como os desafios para a sua conservação por países neotropicais, também são abordados. Apesar de escassos e geograficamente concentrados, um número crescente de estudos tem mostrado que as LCN são sistemas fisiograficamente diversificados, abrigando uma proporção considerável da biodiversidade dos ambientes aquáticos continentais neotropicais. Apesar de as lagoas costeiras representarem ecótonos bastante conectados ao ambiente adjacente, elas desenvolveram mecanismos próprios de regulação funcional e estrutural, conferindo uma maior produtividade e capacidade de suporte em relação...

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Section: The Functioning Process and Services Of Nclsupporting

confidence: 74%

Neotropical coastal lagoons: an appraisal of their biodiversity, functioning, threats and conservation management

et al. 2008

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“…To be incorporated into the microbial food web, large DOC molecules might be broken by sunlight into smaller and potentially more labile entities (Jørgensen et al, 1998;Wiegner and Seitzinger, 2001). About 17 % of the DOC was reported to be biologically available in lake, river, and marine ecosystems (Sondergaard and Middelboe, 1995). Recently, studies have shown that a significant fraction (∼ 30 %) of Arctic river DOC is degradable in the Arctic Ocean on a scale of 1-2 years (Alling et al, 2010;Holmes et al, 2008) -longer than the shallow shelf water residence time, which is on the order of several weeks (Nikiforov and Shpaikher, 1980;Semiletov et al, 2000).…”

Section: Biogeochemical Signatures Of Organic Matter Degradation In Smentioning

confidence: 99%

Space–time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay and adjacent part of the Laptev Sea

et al. 2013

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This study aims to improve understanding of carbon cycling in the Buor-Khaya Bay (BKB) and adjacent part of the Laptev Sea by studying the inter-annual, seasonal, and meso-scale variability of carbon and related hydrological and biogeochemical parameters in the water, as well as factors controlling carbon dioxide (CO₂) emission. Here we present data sets obtained on summer cruises and winter expeditions during 12 yr of investigation. Based on data analysis, we suggest that in the heterotrophic BKB area, input of terrestrially borne organic carbon (OC) varies seasonally and inter-annually and is largely determined by rates of coastal erosion and river discharge. Two different BKB sedimentation regimes were revealed: Type 1 (erosion accumulation) and Type 2 (accumulation). A Type 1 sedimentation regime occurs more often and is believed to be the quantitatively most important mechanism for suspended particular matter (SPM) and particulate organic carbon (POC) delivery to the BKB. The mean SPM concentration observed in the BKB under a Type 1 regime was one order of magnitude greater than the mean concentration of SPM (~ 20 mg L⁻¹) observed along the Lena River stream in summer 2003. Loadings of the BKB water column with particulate material vary by more than a factor of two between the two regimes. Higher partial pressure of CO₂ (pCO₂), higher concentrations of nutrients, and lower levels of oxygen saturation were observed in the bottom water near the eroded coasts, implying that coastal erosion and subsequent oxidation of eroded organic matter (OM) rather than the Lena River serves as the predominant source of nutrients to the BKB. Atmospheric CO₂ fluxes from the sea surface in the BKB vary from 1 to 95 mmol m⁻² day⁻¹ and are determined by specific features of hydrology and wind conditions, which change spatially, seasonally, and inter-annually. Mean values of CO₂ emission from the shallow Laptev Sea were similar in September 1999 and 2005 (7.2 and 7.8 mmol m⁻² day⁻¹, respectively), while the CO₂ efflux can be one order lower after a strong storm such as in September 2011. Atmospheric CO₂ emissions from a thawed coastal ice complex in the BKB area varied from 9 to 439 mmol m⁻² day⁻¹, with the mean value ranged from 75.7 to 101 mmol m⁻² day⁻¹ in two years (September 2006 and 2009), suggesting that at the time of observations the eroded coastal area served as a more significant source of CO₂ to the atmosphere than the tundra (mean value: 22.7 mmol m⁻² day⁻¹) on the neighboring Primorsky coastal plain (September 2006). The observed increase in the Lena River discharge since the 1990s suggests that increased levels of "satellite-derived" annual primary production could be explained by an increasing load of humic acids delivered to shelf water; in this water the color resulting from the presence of CDOM (colo...

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“…This fractionation between LDOC and SRDOC intends to represent the release of compounds of different labilities during cell lysis and sloppy feeding processes. The 10% attributed to the LDOC pool in the model is also close to the fraction of total DOC that is considered to be most labile (Sondergaard and Middelboe, 1995). We did not explicitly represent the labile fraction of DOP and DON in our model.…”

Section: Overviewmentioning

confidence: 99%

Accumulation of DOC in Low Phosphate Low Chlorophyll (LPLC) area: is it related to higher production under high N:P ratio?

2011

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Abstract. The biogeochemistry of carbon and nutrients (N,P) in the surface layer of the ocean strongly depends on the complex interactions between primary producers (phytoplankton) and remineralizers (heterotrophic bacteria). To understand how these interactions impact the overall DOC dynamics in the surface layer of the Mediterranean Sea, we implemented, using Eco3M (Ecological Mechanistic Modular Modelling tool), a multi-element model with a mechanistic description of primary production. We studied the model steady state results under various nutrient conditions and fixed cell abundances. By doing so, we show how the bottom up control of osmotrophs growth can impact the overall DOC dynamics in the system. Based on our set of parameters, the biogeochemical characteristics displayed by the model appear realistic when compared to literature data for the Mediterranean basin. Differences in DOC dynamics between N and P limited systems in the model, lead to the conclusion that the unusually high N:P ratio of the Mediterranean Sea may favour the uncoupling between growth and carbon production leading to higher DOC accumulation compared to systems with lower N:P ratio.

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A cross-system analysis of labile dissolved organic carbon

Cited by 296 publications

References 63 publications

Neotropical coastal lagoons: an appraisal of their biodiversity, functioning, threats and conservation management

Neotropical coastal lagoons: an appraisal of their biodiversity, functioning, threats and conservation management

Space–time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay and adjacent part of the Laptev Sea

Accumulation of DOC in Low Phosphate Low Chlorophyll (LPLC) area: is it related to higher production under high N:P ratio?

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