Methane and nitrous oxide fluxes in the polluted Adyar River and estuary, SE India

Rajkumar, A.; Barnes, Jonathan; Ramachandran, Ramesh; Upstill‐Goddard, Robert C.

doi:10.1016/j.marpolbul.2008.08.005

Cited by 124 publications

(55 citation statements)

References 52 publications

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“…As much as 158,000 % CH 4 saturation has been reported in the Sado estuary, Portugal (Middelburg et al 2002). The highest value recorded exceeds 3,000,000 % for the small, polluted subtropical Aydar estuary in SE India (Nirmal Rajkumar et al 2008). This may be considered exceptional, resulting from a high organic carbon input in fresh domestic organic wastes and intense sediment methanogenesis.…”

Section: Coastal Watersmentioning

confidence: 88%

“…This results in a rapid, episodic release of CH 4 enriched bubbles to the water column (ebullition) and potentially directly to the troposphere with minimal oxidation (Dimitrov 2002). CH 4 ebullition may typically exceed the diffusional sediment CH 4 flux by more than an order of magnitude (Ostrovsky 2003;Barnes et al 2006;Nirmal Rajkumar et al 2008). However, ebullition is notoriously difficult to quantify because spatial and temporal variability can confound attempts to accurately capture a representative sample.…”

Section: Coastal Sedimentsmentioning

confidence: 99%

See 1 more Smart Citation

Air-Sea Interactions of Natural Long-Lived Greenhouse Gases (CO2, N2O, CH4) in a Changing Climate

Bakker

Bange

Gruber

et al. 2013

Ocean-Atmosphere Interactions of Gases and Particles

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Understanding and quantifying ocean-atmosphere exchanges of the long-lived greenhouse gases carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ) are important for understanding the global biogeochemical cycles of carbon and nitrogen in the context of ongoing global climate change. In this chapter we summarise our current state of knowledge regarding the oceanic distributions, formation and consumption pathways, and oceanic uptake and emissions of CO 2 , N 2 O and CH 4 , with a particular emphasis on the upper ocean. We specifically consider the role of the ocean in regulating the tropospheric content of these important radiative gases in a world in which their tropospheric content is rapidly increasing and estimate the impact of global change on their present and future oceanic uptake and/or emission. Finally, we evaluate the various uncertainties associated with the most commonly used methods for estimating uptake and emission and identify future research needs.

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Section: Coastal Watersmentioning

confidence: 88%

Section: Coastal Sedimentsmentioning

confidence: 99%

Air-Sea Interactions of Natural Long-Lived Greenhouse Gases (CO2, N2O, CH4) in a Changing Climate

Bakker

Bange

Gruber

et al. 2013

Ocean-Atmosphere Interactions of Gases and Particles

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“…[40] Transient periods of N 2 O undersaturation and uptake have been observed [Hemond and Duran, 1989;Stow et al, 2005;Beaulieu et al, 2008], even in streams and rivers with high annual loads of dissolved inorganic N [McMahon and Dennehy, 1999;Rajkumar et al, 2008]. However, Jackson Creek is the first system to be shown function as a net N 2 O sink on an annual basis.…”

Section: N 2 O Consumptionmentioning

confidence: 99%

“…Periods of net N 2 O consumption have been associated with low ambient NO 3 − concentrations, low O 2 concentrations, low flow, or some combination of these factors [Richey et al, 1988;Hemond and Duran, 1989;LaMontagne et al, 2003;Stow et al, 2005;Rajkumar et al, 2008]. In soils, where N 2 O consumption is more widely documented, factors including temperatures greater than 5°C and low O 2 (or saturation and porosity that drive low O 2 ) have been associated with net N 2 O consumption [Blackmer et al, 1980;Chapuis-Lardy et al, 2007].…”

Section: N 2 O Consumptionmentioning

confidence: 99%

Nitrogen enrichment and the emission of nitrous oxide from streams

Baulch¹,

Schiff²,

Maranger³

et al. 2011

Global Biogeochem. Cycles

120

101

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[1] Nitrous oxide (N 2 O) is a potent greenhouse gas produced during nitrogen cycling. Global nitrogen enrichment has resulted in increased atmospheric N 2 O concentrations due in large part to increased soil emissions. There is also a potentially important flux from streams, rivers and estuaries; although measurements of these emissions are sparse, and role of aquatic ecosystems in global N 2 O budgets remains highly uncertain. Using the longest-term measurements of N 2 O fluxes from streams to date, we found annual fluxes from 14 sites in five streams of south-central Ontario, Canada varied widely-from net uptake of 3.2 ± 0.2 (standard deviation) mmol N 2 O m −2 d −1 to net release of 776 ± 61 mmol N 2 O m −2 d −1 . N 2 O consumption was associated with very low nitrate concentrations (<2.7 mM). Mean annual (log-transformed) N 2 O emissions from our study streams (across sites and years) were positively related to nitrate concentrations (r 2 = 0.59).This nitrate-N 2 O relationship can be generalized across all 20 streams (in Canada, Japan, Mexico, and the midwestern United States) for which published data now exist and could provide a new basis for the IPCC to calculate agricultural emissions from streams. In addition to predicting annual emissions, we present the first measurements of N 2 O concentrations under ice in streams. Nitrate was a strong predictor of N 2 O % saturation during periods of ice cover (r 2 = 0.89), when gas exchange is negligible. Given the small surface area of streams within a catchment and the fact our measured areal fluxes are comparable to reported fluxes from agricultural soils, this suggests streams are a small regional N 2 O source.Citation: Baulch, H. M., S. L. Schiff, R. Maranger, and P. J. Dillon (2011), Nitrogen enrichment and the emission of nitrous oxide from streams, Global Biogeochem. Cycles, 25, GB4013,

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“…(e.g., Hashimoto et al 1999), all of which are concentrated in MCCZ. The combined effects of pressures described in the ''Marine ecosystem responses'' section can make these limited areas relatively important sources of CH 4 and nitrous oxide (Nirmal Rajkumar et al 2008). Ozone and CH 4 are the only greenhouse gases destroyed within the troposphere; the chemistry of O 3 specific to MCCZ was discussed above.…”

Section: Greenhouse Gasesmentioning

confidence: 99%

Megacities and Large Urban Agglomerations in the Coastal Zone: Interactions Between Atmosphere, Land, and Marine Ecosystems

Glasow

Jickells

Baklanov

et al. 2012

AMBIO

Self Cite

127

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Megacities are not only important drivers for socio-economic development but also sources of environmental challenges. Many megacities and large urban agglomerations are located in the coastal zone where land, atmosphere, and ocean meet, posing multiple environmental challenges which we consider here. The atmospheric flow around megacities is complicated by urban heat island effects and topographic flows and sea breezes and influences air pollution and human health. The outflow of polluted air over the ocean perturbs biogeochemical processes. Contaminant inputs can damage downstream coastal zone ecosystem function and resources including fisheries, induce harmful algal blooms and feedback to the atmosphere via marine emissions. The scale of influence of megacities in the coastal zone is hundreds to thousands of kilometers in the atmosphere and tens to hundreds of kilometers in the ocean. We list research needs to further our understanding of coastal megacities with the ultimate aim to improve their environmental management.

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Methane and nitrous oxide fluxes in the polluted Adyar River and estuary, SE India

Cited by 124 publications

References 52 publications

Air-Sea Interactions of Natural Long-Lived Greenhouse Gases (CO2, N2O, CH4) in a Changing Climate

Air-Sea Interactions of Natural Long-Lived Greenhouse Gases (CO2, N2O, CH4) in a Changing Climate

Nitrogen enrichment and the emission of nitrous oxide from streams

Megacities and Large Urban Agglomerations in the Coastal Zone: Interactions Between Atmosphere, Land, and Marine Ecosystems

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