The estuarine mixing behaviour of peatland derived dissolved organic carbon and its relationship to chromophoric dissolved organic matter in two North Sea estuaries (U.K.)

Spencer, Robert G. M.; Ahad, Jason M. E.; Baker, Andy; Cowie, Gregory L.; Ganeshram, Raja S.; Upstill‐Goddard, Robert C.; Uher, G

doi:10.1016/j.ecss.2007.03.032

Cited by 80 publications

(79 citation statements)

References 48 publications

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“…Sholkovitch et al, 1978), although studies of DOC removal in estuaries receiving water from peat catchments provide conflicting evidence of the importance of this process (e.g. Álvarez-Selgado and Miller, 1998;Spencer et al, 2007;Palmer et al, this volume) making it difficult to generalise. For terrestrial DOC that does reach the ocean, it appears that (although specific values for peat-derived DOC are not available) most DOC is microbially processed, on a timescale of years to decades (e.g.…”

Section: Contribution Of Peat Doc Fluxes To Co2 Emissionsmentioning

confidence: 99%

The role of waterborne carbon in the greenhouse gas balance of drained and re-wetted peatlands

2015

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Article (refereed) -postprintEvans, Chris D.; Renou-Wilson, Flo; Strack, Maria. 2016. The role of waterborne carbon in the greenhouse gas balance of drained and rewetted peatlands [in special issue: Carbon cycling in aquatic ecosystems] Aquatic Sciences, 78 (3). 573-590. 10.1007/s00027-015-0447-y Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.The role of waterborne carbon in the greenhouse gas balance of drained and re-wetted peatlands AbstractAccounting for greenhouse gas (GHG) emissions and removals in managed ecosystems has generally focused on direct land-atmosphere fluxes, but in peatlands a significant proportion of total carbon loss occurs via fluvial transport. This study considers the composition of this 'waterborne carbon' flux, its potential contribution to GHG emissions, and the extent to which it may change in response to land-management. The work describes, and builds on, a methodology to account for major components of these emissions developed for the 2013 Wetland Supplement of the Intergovernmental Panel on Climate Change. We identify two major components of GHG emissions from waterbodies draining organic soil: i) 'on site' emissions of methane (and to a lesser extent CO2) from drainage ditches located within the peatland; and ii) 'off site' emissions of CO2 resulting from downstream oxidation of dissolved and particulate organic carbon (DOC and POC) within the aquatic system. Methane emissions from ditches were found to be large in many cases (mean 60 g CH4 m -2 yr -1 based on all reported values), countering the view that methane emissions cease following wetland drainage. Emissions were greatest from ditches in intensive agricultural peatlands, but data were sparse and showed high variability. For DOC, the magnitude of the natural flux varied strongly with latitude, from 5 g C m -2 yr -1 in northern boreal peatlands to 60 g C m -2 yr -1 in tropical peatlands. Available data suggest that DOC fluxes increase by around 60% following drainage, and that this increase may be reversed in the longer-term through re-wetting, although variability between studies was high, especially in relation to re-wetting response. Evidence regarding the fate of DOC is complex and inconclusive, but overall suggests that the majority of DOC exported from peatlands is converted to CO2 through photo-and/or bio-degradation in rivers, standing waters and oceans. The contribution of POC export to GHG emissions is even more uncertain, but we estimate that over half of exported POC may eventually be converted to CO2. Although POC fluxes are normally small, they can become very large when bare peat surfaces are exposed to fluvial erosion. Overall, we estimate that waterborne carbon emissions may contribute about 1 to 4 t CO2-eq ha -1 yr -1 of additional GHG emissions from drained peatlands. For a number of worked examples this repres...

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Section: Contribution Of Peat Doc Fluxes To Co2 Emissionsmentioning

confidence: 99%

The role of waterborne carbon in the greenhouse gas balance of drained and re-wetted peatlands

2015

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“…Both the magnitudes and spectral shapes of CDOM absorption coefficients have been linked to their composition and sources Twardowski et al, 2004), and are mainly driven by continental sources Schofield et al, 2004). Substantial disposal of sewage can also affect the CDOM absorption parameters and the proportion of nonalgal particles in the water column (Abril et al, 2002;Callahan et al, 2004;Spencer et al, 2007). Tidal oscillation and biogeochemical interactions may be also important in driving an area optically (e.g., Shi et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Variability in the light absorption coefficients of phytoplankton, non-algal particles, and colored dissolved organic matter in a subtropical bay (Brazil)

Ferreira

Ciotti

Giannini

2014

Estuarine, Coastal and Shelf Science

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“…Although the extent of DOM utilization in estuaries depends largely on its chemical composition (Sondergaard et al 2003;Fellman et al 2010b), its fate is also determined by complex interactions between biological, hydrodynamic, and photochemical processes. For example, as much as 58% of dissolved organic carbon (DOC) may be removed from estuarine water columns (Spencer et al 2007a) via photochemical degradation (Hernes and Benner 2003;Spencer et al 2009), bacterial metabolism (Raymond and Bauer 2000), or physicochemical transformations (e.g., flocculation; Sholkovitz et al 1978;Amon and Meon 2004). Conversely, terrigenous DOM can behave conservatively in coastal ecosystems as shown by slight modification of DOM precursor material in estuarine transect studies off the Florida coast (Jaffe et al 2004).…”

mentioning

confidence: 99%

“…For example, fluorescence DOM characterization can discriminate allochthonous and autochthonous sources of DOM in coastal environments (Coble 1996;Spencer et al 2007b). This technique has also shown contrasting estuarine mixing behavior for DOM fractions, from simple conservative mixing of humic-like components derived from catchment sources of higher plant material to nonconservative mixing of protein-like components (Yamashita et al 2008;Kowalczuk et al 2009).…”

mentioning

confidence: 99%

Source, biogeochemical cycling, and fluorescence characteristics of dissolved organic matter in an agro‐urban estuary

Fellman¹,

Petrone²,

Grierson³

2010

Limnology & Oceanography

102

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Seasonal measurements of dissolved organic matter (DOM) fluorescence characteristics were combined with weekly to bi-weekly measurements of carbon (C), nitrogen (N), and phosphorus (P) (including particulate, dissolved organic and inorganic forms) and chlorophyll to determine how riverine inputs and autochthonous production influence DOM and nutrient dynamics in the Swan-Canning estuary, Western Australia. Estuarine concentrations of C, N, and P were influenced by multiple factors, including the seasonal riverine flux of DOM, N, and P, the regeneration of mainly inorganic N and P from benthic anoxia, and the delivery of DOM and nutrients from urban drains. Parallel factor analysis of excitation-emission matrices identified eight fluorescence components that were used to fingerprint three distinct sources of estuarine DOM: (1) riverine DOM derived mainly from vascular plant material, (2) autochthonous DOM recently produced within the estuary (indicated by tryptophan-like fluorescence), and (3) autochthonous DOM originating from within the lower estuary or coastal marine environment enriched in marine humic-like and tyrosine-like fluorescence. Overall, fluorescence DOM characteristics shifted from humic-like in the upper and mid-estuary to protein-like in the lower estuary, which likely reflects the increased contribution of autochthonous relative to terrigenous DOM closer to the estuary mouth. Our findings show that DOM composition varies with season and estuary position as riverine DOM inputs, mainly from terrestrial plant material, are supplemented by autochthonous DOM contributions associated with discrete inputs of inorganic nutrients.

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The estuarine mixing behaviour of peatland derived dissolved organic carbon and its relationship to chromophoric dissolved organic matter in two North Sea estuaries (U.K.)

Cited by 80 publications

References 48 publications

The role of waterborne carbon in the greenhouse gas balance of drained and re-wetted peatlands

The role of waterborne carbon in the greenhouse gas balance of drained and re-wetted peatlands

Variability in the light absorption coefficients of phytoplankton, non-algal particles, and colored dissolved organic matter in a subtropical bay (Brazil)

Source, biogeochemical cycling, and fluorescence characteristics of dissolved organic matter in an agro‐urban estuary

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