scholarly journals Seasonal variability of the inorganic carbon system in a large coastal plain estuary

2017 ◽  
Vol 14 (21) ◽  
pp. 4949-4963 ◽  
Author(s):  
Andrew Joesoef ◽  
David L. Kirchman ◽  
Christopher K. Sommerfield ◽  
Wei-Jun Cai
Keyword(s):  
Inorganic Carbon ◽  
Drainage Basin ◽  
Dissolved Inorganic Carbon ◽  
Coastal Ocean ◽  
Total Alkalinity ◽  
Delaware Estuary ◽  
Terrestrial Organic Matter ◽  
Delaware River ◽  
Export Flux ◽  
Carbon System

Abstract. Carbonate geochemistry research in large estuarine systems is limited. More work is needed to understand how changes in land-use activity influence watershed export of organic and inorganic carbon, acids, and nutrients to the coastal ocean. To investigate the seasonal variation of the inorganic carbon system in the Delaware Estuary, one of the largest estuaries along the US east coast, dissolved inorganic carbon (DIC), total alkalinity (TA), and pH were measured along the estuary from June 2013 to April 2015. In addition, DIC, TA, and pH were periodically measured from March to October 2015 in the nontidal freshwater Delaware, Schuylkill, and Christina rivers over a range of discharge conditions. There were strong negative relationships between river TA and discharge, suggesting that changes in HCO3− concentrations reflect dilution of weathering products in the drainage basin. The ratio of DIC to TA, an understudied but important property, was high (1.11) during high discharge and low (0.94) during low discharge, reflecting additional DIC input in the form of carbon dioxide (CO2), most likely from terrestrial organic matter decomposition, rather than bicarbonate (HCO3−) inputs due to drainage basin weathering processes. This is also a result of CO2 loss to the atmosphere due to rapid water transit during the wet season. Our data further show that elevated DIC in the Schuylkill River is substantially different than that in the Delaware River. Thus, tributary contributions must be considered when attributing estuarine DIC sources to the internal carbon cycle versus external processes such as drainage basin mineralogy, weathering intensity, and discharge patterns. Long-term records in the Delaware and Schuylkill rivers indicate shifts toward higher alkalinity in estuarine waters over time, as has been found in other estuaries worldwide. Annual DIC input flux to the estuary and export flux to the coastal ocean are estimated to be 15.7 ± 8.2  ×  109 mol C yr−1 and 16.5 ± 10.6  ×  109 mol C yr−1, respectively, while net DIC production within the estuary including inputs from intertidal marshes is estimated to be 5.1  ×  109 mol C yr−1. The small difference between riverine input and export flux suggests that, in the case of the Delaware Estuary and perhaps other large coastal systems with long freshwater residence times, the majority of the DIC produced in the estuary by biological processes is exchanged with the atmosphere rather than exported to the sea.

scholarly journals Seasonal variability of the inorganic carbon system in a large coastal plain estuary

2017 ◽  
Author(s):  
Andrew Joesoef ◽  
David L. Kirchman ◽  
Christopher K. Sommerfield ◽  
Wei-Jun Cai
Keyword(s):  
Land Surface ◽  
Inorganic Carbon ◽  
Drainage Basin ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Balance Model ◽  
Delaware Estuary ◽  
Delaware River ◽  
Schuylkill River ◽  
Carbon System

Abstract. Carbonate geochemistry research in large estuarine systems is limited and widely understudied. Further, changes in land use activity have profoundly influenced watershed export of organic and inorganic carbon, acids, and nutrients to the coastal ocean. To investigate the seasonal variation of the inorganic carbon system in the Delaware Estuary, one of the largest estuaries along the U.S. east coast, dissolved inorganic carbon (DIC), total alkalinity (TA), and pH were measured down the estuary from June 2013 to April 2015. In addition, to explore how drainage basin mineralogy, weathering intensity, and tributary discharge impact total riverine DIC and TA fluxes to the estuary and export fluxes to the ocean, DIC, TA, and pH were periodically measured from March to October 2015 in the non-tidal freshwater Delaware, Schuylkill, and Christina rivers. Strong negative relationships between river TA and discharge support that changes in HCO3− concentrations reflect the dilution of the weathering derived products in the drainage basin. The ratio of DIC to TA, a rarely studied but important property, is high (1.11) during high discharge and low (0.94) during low discharge, reflecting additional CO2 input most likely from land surface organic matter decomposition other than HCO3− input from the drainage basin weathering processes. Our data further suggest that DIC in the Schuylkill River can be substantially different from DIC in the Delaware River, and thus in any river system, tributary contributions must be considered when addressing DIC inputs to the estuary. Long-term records of increasing alkalinity in the Delaware and Schuylkill river support global shifts toward higher alkalinity in estuarine waters with time. Annual DIC input flux to the estuary and export flux to the ocean are estimated to be 15.7 ± 8.2 × 109 mol C yr−1 and 16.5 ± 10.6 × 109 mol C yr−1, respectively. CO2 flux produced within the estuary inclusive of inputs from intertidal marshes is small (5.1 × 109 mol C yr−1) when compared to total riverine flux. This finding suggests that, in the case of the Delaware Estuary and perhaps other large coastal systems with long freshwater residence times, the majority of the DIC produced by biological processes is exchanged with the atmosphere rather than exported to the sea. Based on a CO2 mass balance model, we concluded that annually the Delaware Estuary is a weak heterotrophic system (−1.3 ± 3.8 mol C m−2 yr−1), which is in contrast to many highly heterotrophic smaller estuaries.

scholarly journals Inorganic carbon fluxes on the Mackenzie Shelf of the Beaufort Sea

2017 ◽  
Author(s):  
Jacoba Mol ◽  
Helmuth Thomas ◽  
Paul G. Myers ◽  
Xianmin Hu ◽  
Alfonso Mucci
Keyword(s):  
Sea Ice ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Beaufort Sea ◽  
Total Alkalinity ◽  
The Arctic ◽  
Surface Mixed Layer ◽  
Saturation State ◽  
Carbon Transfer ◽  
Mackenzie Shelf

Abstract. The Mackenzie Shelf in the southeastern Beaufort Sea is a region that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds, resulting in cross-shelf Ekman transport, and an alternating estuarine and anti-estuarine circulation. Downwelling carries inorganic carbon and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world oceans. Upwelling carries dissolved inorganic carbon (DIC) and nutrient-rich waters from the Pacific-origin upper halocline layer (UHL) onto the shelf. Profiles of DIC and total alkalinity (TA) taken in August and September of 2014 are used to investigate the cycling of inorganic carbon on the Mackenzie Shelf. The along-shore transport of water and the cross-shelf transport of inorganic carbon are quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4) configuration of the Nucleus of European Modelling of the Ocean (NEMO) framework. A strong upwelling event prior to sampling on the Mackenzie Shelf is analyzed and the resulting influence on the carbonate system, including the saturation state of waters with respect to aragonite and pH, is investigated. TA and the oxygen isotope ratio of water (δ18O) are used to examine water-mass distributions in the study area and to investigate the influence of Pacific Water, Mackenzie River freshwater, and sea-ice melt on carbon dynamics and air-sea fluxes of carbon dioxide (CO2) in the surface mixed layer. Understanding carbon transfer in this seasonally dynamic environment is key to quantify the importance of Arctic shelf regions to the global carbon cycle and provide a basis for understanding how it will respond to the aforementioned climate-induced changes.

Small-Scale Gradients in Big River: Implications for a State-of-the-Art Research Platform in the Elbe

2021 ◽  
Author(s):  
Sina Bold ◽  
Justus E.E. van Beusekom ◽  
Yoana G. Voynova ◽  
Marius Cysewski ◽  
Bryce Van Dam ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Ammonium Phosphate ◽  
Total Alkalinity ◽  
Small Scale ◽  
Suspended Particulate ◽  
Research Platform ◽  
Biogeochemical Parameters ◽  
Art Research ◽  
Set Up

<p>Estuaries are crucial in transforming matter fluxes from land to sea. To better understand and quantify these processes and respective fluxes, it is important to determine the input into an estuary accurately. To allow for such studies in the Elbe estuary in Germany, a state-of-the-art research platform is currently being set-up just upstream of the weir in Geesthacht at the entrance of the estuary. Here, we report on small-scale spatial dynamics of organic matter and associated processes from several cross and longitudinal profiles around the planned location and the implications for the set-up of the aforementioned research platform.</p><p>Based on preliminary data obtained in August 2020 during a period of relatively low discharge, we present the following results: (1) In three cross profiles along a 10 km transect of the Elbe upstream of the weir, we observed considerable small-scale gradients regarding currents and various biogeochemical parameters. In comparison to the fairway, water from the riverbanks was depleted in suspended particulate matter, chlorophyll a, dissolved oxygen, and nitrate, and enhanced in ammonium, phosphate and silicate, as well as total alkalinity and dissolved inorganic carbon paralleled by decreasing pH. This suggests that in the summer, organic matter is deposited and remineralised at the riverbanks, resulting in the release of ammonium, phosphate and silicate, and in the removal of nitrate, presumably by denitrification. (2) Along the 10 km transect towards the weir, we observed that concentrations of suspended particulate matter, chlorophyll a, dissolved oxygen, nitrate and pH were decreasing. In contrast, we found that ammonium, phosphate and silicate, total alkalinity and dissolved inorganic carbon increased towards the weir. This suggests an increased sedimentation and subsequent remineralisation due to the reduced flow velocities in front of the weir. (3) An analysis of a 10-year time series from the weir supports this by showing higher ammonium concentrations when discharges were relatively low. The implications of these findings for the set-up of the research platform in this area, as well as for optimising estimates of budgets are discussed. The research platform will contribute to understand further such variations in biogeochemical parameters at the entrance of the Elbe estuary over time.</p><p>The research platform is set-up in cooperation with the Helmholtz initiative MOSES (“Modular Observation Solutions for Earth Systems“) and will be incorporated in the Elbe-North Sea Supersite of DANUBIUS-RI (“International Centre for Advanced Studies on River-Sea Systems“). Funding is provided by European Regional Development Funds, the federal state of Schleswig-Holstein, the Helmholtz Association and the Helmholtz-Zentrum Geesthacht. The research platform, planned to be operational in autumn 2021, will also be open for users e.g. to develop and test new methods and technologies. Data will be made available through the “Helmholtz Coastal Data Centre” (HCDC).</p>

NZOA-ON: the New Zealand Ocean Acidification Observing Network

2020 ◽  
Vol 71 (3) ◽  
pp. 281 ◽  
Author(s):  
J. M. Vance ◽  
K. I. Currie ◽  
C. S. Law ◽  
J. Murdoch ◽  
J. Zeldis
Keyword(s):  
New Zealand ◽  
Ocean Acidification ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Grass Roots ◽  
The Past ◽  
Field Samples ◽  
The University ◽  
Global Initiatives

A national observing network has been operating over the past 4 years to inform the scientific and economic challenges of ocean acidification (OA) facing New Zealand. The New Zealand Ocean Acidification Observing Network (NZOA-ON) consists of 12 sites across varied coastal ecosystems. These ecosystems range from oligotrophic ocean-dominated systems to eutrophic river-dominated systems, with sites that are pristine or affected by agriculture and urbanisation. Fortnightly measurements of total alkalinity and dissolved inorganic carbon provide the baseline of carbonate chemistry in these varied ecosystems and will facilitate detection of future changes, as well as providing a present-day baseline. The National Institute of Water and Atmospheric Research and the University of Otago have developed a ‘grass-roots’ sampling program, providing training and equipment that enable sampling partners to collect field samples for analyses at a central laboratory. NZOA-ON leverages existing infrastructure and partnerships to maximise data captured for understanding the drivers of chemical changes associated with OA and ecological responses. NZOA-ON coordinates with and contributes to global initiatives to understand and mitigate the broader impacts of OA. A description of NZOA-ON is presented with preliminary analyses and comparison of data from different sites after the first 4 years of the network.

scholarly journals Development of a Biogeochemical and Carbon Model Related to Ocean Acidification Indices with an Operational Ocean Model Product in the North Western Pacific

2019 ◽  
Vol 11 (9) ◽  
pp. 2677 ◽  
Author(s):  
Miho Ishizu ◽  
Yasumasa Miyazawa ◽  
Tomohiko Tsunoda ◽  
Xinyu Guo
Keyword(s):  
Ocean Acidification ◽  
General Circulation ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Ocean Model ◽  
Western Pacific ◽  
Total Alkalinity ◽  
The North ◽  
North Western ◽  
North Western Pacific

We developed a biogeochemical and carbon model (JCOPE_EC) coupled with an operational ocean model for the North Western Pacific. JCOPE_EC represents ocean acidification indices on the background of the risks due to ocean acidification and our model experiences. It is an off-line tracer model driven by a high-resolution regional ocean general circulation model (JCOPE2M). The results showed that the model adequately reproduced the general patterns in the observed data, including the seasonal variability of chlorophyll-a, dissolved inorganic nitrogen/phosphorus, dissolved inorganic carbon, and total alkalinity. We provide an overview of this system and the results of the model validation based on the available observed data. Sensitivity analysis using fixed values for temperature, salinity, dissolved inorganic carbon and total alkalinity helped us identify which variables contributed most to seasonal variations in the ocean acidification indices, pH and Ωarg. The seasonal variation in the pHinsitu was governed mainly by balances of the change in temperature and dissolved inorganic carbon. The seasonal increase in Ωarg from winter to summer was governed mainly by dissolved inorganic carbon levels.

Mangroves as source of alkalinity and dissolved carbon to the coastal ocean: A case study from the Everglades National Park, Florida

2020 ◽  
Author(s):  
Gloria Reithmaier ◽  
David Ho ◽  
Scott Johnston ◽  
Damien Maher
Keyword(s):  
Greenhouse Gas ◽  
National Park ◽  
Dissolved Inorganic Carbon ◽  
River Estuary ◽  
Coastal Ocean ◽  
Everglades National Park ◽  
Total Alkalinity ◽  
Dissolved Carbon ◽  
Gas Fluxes ◽  
Greenhouse Gas Fluxes

<p>Most research evaluating the potential of mangroves as a sink for atmospheric carbon has focused on carbon burial. However, the few studies that have quantified lateral exchange of carbon and alkalinity, indicate that the dissolved carbon and alkalinity export may be several-fold more important than burial. This study aims to investigate rates and drivers of alkalinity, dissolved carbon and greenhouse gas fluxes of the mangrove-dominated Shark River estuary located in the Everglades National Park in Florida, USA. Time series and spatial surveys were conducted to asses total alkalinity (TAlk), organic alkalinity (OAlk), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), carbon dioxide (CO<sub>2</sub>), methane (CH<sub>4</sub>) and nitrous oxide (N<sub>2</sub>O). Dominant metabolic processes driving dissolved carbon and greenhouse gas dynamics varied along the estuary salinity gradient. Dissolved carbon and greenhouse gas concentrations were strongly coupled to porewater input, which was examined using Rn-222. Shark River was a source of CO<sub>2</sub> (92 mmol/m<sup>­2</sup>/d), CH<sub>4</sub> (60 µmol/m<sup>­2</sup>/d) and N<sub>2</sub>O (2 µmol/m­<sup>2</sup>/d) to the atmosphere. Dissolved carbon export (DIC = 142 mmol/m­<sup>2</sup>/d, DOC = 39 mmol/m­<sup>2</sup>/d) was several-fold higher than burial (~28 mmol/m<sup>2</sup>/d) and represents an additional carbon sink. Furthermore, the estuary was a source of TAlk (97 mmol/m­<sup>2</sup>/d) to the coastal ocean, potentially buffering coastal acidification. Despite accounting for only a small share of TAlk, OAlk had a large effect on the estuarine pH. By integrating our results with previous studies, we argue that alkalinity, dissolved carbon and greenhouse gas fluxes should be considered in future blue carbon budgets.</p>

The influence of macronitrogen (NO 3 − and NH 4 + ) addition with Ulva pertusa on dissolved inorganic carbon system

2012 ◽  
Vol 31 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Naixing Zhang ◽  
Jinming Song ◽  
Conghua Cao ◽  
Rongzhu Ren ◽  
Fengcong Wu ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Ulva Pertusa ◽  
Carbon System
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