Turbidity limits gas exchange in a large macrotidal estuary

Abril, Gwénaël; Commarieu, Marc-Vincent; Sottolichio, Aldo; Bretel, Patrice; Guerin, Frédéric

doi:10.1016/j.ecss.2009.03.006

Cited by 77 publications

(81 citation statements)

References 28 publications

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“…Wanninkhof 1992), noble gas based estimates are sensitive to site specific conditions, including the effects of precipitation, surfactant films, and bottom-generated turbulence Harrison et al 2012). Sampling does not alter turbulence at the air-water interface, a drawback of measurements from floating dome studies, and tracer dispersal does not limit sampling period or location as with deliberate tracer releases (Abril et al 2009;. The noble gas method has drawbacks as well, including uncertainty in the solubility of Kr and Xe and potentially large sampling errors caused by small bubbles or air leaks in the samples.…”

Section: Noble Gas Concentrations As Tracers Of Gas Exchange Propertiesmentioning

confidence: 99%

Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments

Howard¹

2017

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Salt marshes are physically, chemically, and biologically dynamic environments found globally at temperate latitudes. Tidal creeks and marshtop ponds may expand at the expense of productive grasscovered marsh platform. It is therefore important to understand the present magnitude and drivers of production and respiration in these submerged environments in order to evaluate the future role of salt marshes as a carbon sink. This thesis describes new methods to apply the triple oxygen isotope tracer of photosynthetic production in a salt marsh. Additionally, noble gases are applied to constrain air-water exchange processes which affect metabolism tracers. These stable, natural abundance tracers complement traditional techniques for measuring metabolism. In particular, they highlight the potential importance of daytime oxygen sinks besides aerobic respiration, such as rising bubbles. In tidal creeks, increasing nutrients may increase both production and respiration, without any apparent change in the net metabolism. In ponds, daytime production and respiration are also tightly coupled, but there is high background respiration regardless of changes in daytime production. Both tidal creeks and ponds have higher respiration rates and lower production rates than the marsh platform, suggesting that expansion of these submerged environments could limit the ability of salt marshes to sequester carbon. AcknowledgmentsFinancial support for my doctoral research was provided by the United States Department of Defense through the National Defense Science and Engineering Graduate Fellowship Program, the National Science Foundation under grant OCE-1233678, and the Woods Hole Oceanographic Institution (WHOI) under grants from the WHOI Coastal Ocean Institute, Ocean and Climate Change Institute, and Ocean Life Institute. WHOI Academic Programs Office also provided funding support for research, through the Ocean Ventures Fund, and for my stipend, as graduate research assistantships including an assistantship from the United States Geological Survey administered by WHOI. I am very grateful for this financial support which allowed me earn a living wage while focused on my doctoral research.In addition, the great majority of this work would not have been possible without the outstanding logistical and in kind support of many scientific teams and individuals, including the Plum Island Ecosystems Long Term Ecological Research site and TIDE experiment staff and scientists (these projects funded by NSF OCE 1238212, NSF DEB 1354494, and NE Climate Science Center grant DOI G12AC00001), Nancy Pau at the Parker River National Wildlife Refuge who granted permits for the work in Chapters 4 and 5, and Liz Kujawinski and Krista Longnecker at WHOI who invited me to participate on cruise KN210-04 in the South Atlantic (funded by NSF grant OCE 1154320).Specific acknowledgments are also found in each chapter of this thesis, but I'd like to thank a number of individuals in particular who helped me plan for, collect, and analyze the data that u...

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Section: Noble Gas Concentrations As Tracers Of Gas Exchange Propertiesmentioning

confidence: 99%

Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments

Howard¹

2017

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“…Due to a lack of appropriate equipment, the piston velocity was estimated from wind speed instead of measured directly. There has been much discussion of the best method to estimate the piston velocity of CO 2 in estuaries, which is heavily dependent upon wind, but may also be affected by wave slope, surface films, rain, bottom-generated turbulence, surface turbulence, turbidity, and fetch limitation (Raymond and Cole 2001;Zappa et al 2007;Borges et al 2004a;Abril et al 2009). A paper by Ho et al (2011) examined the estimation of air-water gas exchange in the Hudson River, another northeastern USA estuary.…”

Section: −1mentioning

confidence: 99%

CO2 Input Dynamics and Air–Sea Exchange in a Large New England Estuary

Hunt

Salisbury

Vandemark

2013

Estuaries and Coasts

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Repeated surveys of the Kennebec estuary, a macrotidal river estuary in Maine, USA, between 2004 and 2008 found spatial and temporal variability both in sources of carbon dioxide (CO 2 ) to the estuary and the air-sea flux of estuary CO 2 . On an annual basis, the surveyed area of the Kennebec estuary had an area-weighted average partial pressure of CO 2 (pCO 2 ) of 559 μatm. The area-weighted average CO 2 flux to the atmosphere was 3.54 mol C m −2 year −1 .Overall, the Kennebec estuary was an annual source of 7.2× 10 7 mol CO 2 to the atmosphere. Distinct seasonality in estuarine pCO 2 was observed, with shifts in the seasonal pattern evident between lower and higher salinities. Fluxes of CO 2 from the estuary were elevated following two summertime storms, and inputs of riverine CO 2 outweighed internal estuarine CO 2 inputs in nearly all months. River and estuarine inputs of CO 2 represented 68 and 32 % of the total CO 2 contributions to the estuary, respectively. This study examines the variability of CO 2 in a large New England estuary, and highlights the comparatively high contribution of CO 2 from riverine sources.

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“…The Raymond and Cole (2001) (RC01) equation is based on the compilation of gas transfer velocities derived from tracers applied to nine rivers and estuaries, using only wind speed as an entry parameter. The Abril et al (2009) (A09) relationship is based on chamber flux measurements in seven estuaries, and uses wind speed, estuarine surface area, and water current velocity as entry parameters. We also calculated the fluxes with the parameterization of Wanninkhof (1992) (W92), which was initially developed for open ocean waters.…”

Section: Calculationsmentioning

confidence: 99%

“…We used the k wind parameterizations of Raymond and Cole (2001) and Abril et al (2009), which are gas exchange coefficients specific for estuarine waters. The Raymond and Cole (2001) (RC01) equation is based on the compilation of gas transfer velocities derived from tracers applied to nine rivers and estuaries, using only wind speed as an entry parameter.…”

Section: Calculationsmentioning

confidence: 99%

A strong CO<sub>2</sub> sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)

et al. 2015

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Abstract. In contrast to its small surface area, the coastal zone plays a disproportionate role in the global carbon cycle. Carbon production, transformation, emission and burial rates at the land-ocean interface are significant at the global scale but still poorly known, especially in tropical regions. Surface water pCO 2 and ancillary parameters were monitored during nine field campaigns between April 2013 and April 2014 in Guanabara Bay, a tropical eutrophic to hypertrophic semienclosed estuarine embayment surrounded by the city of Rio de Janeiro, southeast Brazil. Water pCO 2 varied between 22 and 3715 ppmv in the bay, showing spatial, diurnal and seasonal trends that mirrored those of dissolved oxygen (DO) and chlorophyll a (Chl a). Marked pCO 2 undersaturation was prevalent in the shallow, confined and thermally stratified waters of the upper bay, whereas pCO 2 oversaturation was restricted to sites close to the small river mouths and small sewage channels, which covered only 10 % of the bay's area. Substantial daily variations in pCO 2 (up to 395 ppmv between dawn and dusk) were also registered and could be integrated temporally and spatially for the establishment of net diurnal, seasonal and annual CO 2 fluxes. In contrast to other estuaries worldwide, Guanabara Bay behaved as a net sink of atmospheric CO 2 , a property enhanced by the concomitant effects of strong radiation intensity, thermal stratification, and high availability of nutrients, which promotes phytoplankton development and net autotrophy. The calculated CO 2 fluxes for Guanabara Bay ranged between −9.6 and −18.3 mol C m −2 yr −1 , of the same order of magnitude as the organic carbon burial and organic carbon inputs from the watershed. The positive and high net community production (52.1 mol C m −2 yr −1 ) confirms the high carbon production in the bay. This autotrophic metabolism is apparently enhanced by eutrophication. Our results show that global CO 2 budgetary assertions still lack information on tropical, marine-dominated estuarine systems, which are affected by thermal stratification and eutrophication and behave specifically with respect to atmospheric CO 2 .

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Turbidity limits gas exchange in a large macrotidal estuary

Cited by 77 publications

References 28 publications

Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments

Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments

CO2 Input Dynamics and Air–Sea Exchange in a Large New England Estuary

A strong CO<sub>2</sub> sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)

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Turbidity limits gas exchange in a large macrotidal estuary

Cited by 77 publications

References 28 publications

Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments

Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments

CO2 Input Dynamics and Air–Sea Exchange in a Large New England Estuary

A strong CO&lt;sub&gt;2&lt;/sub&gt; sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)

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A strong CO<sub>2</sub> sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)