Carbonate system properties in the Gerlache Strait, Northern Antarctic Peninsula (February 2015): II. Anthropogenic CO2 and seawater acidification

Abstract. We relate here the distributions of two carbonate system key properties (total alkalinity, AT; and total dissolved inorganic carbon, CT) measured along a section in the Mediterranean Sea, going from Marseille (France) to the south of the Cyprus Island, during the 2008 BOUM cruise. The three main objectives of the present study are (1) to draw and comment on the distributions of AT and CT in the light of others properties like salinity, temperature, and dissolved oxygen, (2) to estimate the distribution of the anthropogenic CO2 (CANT) in the intermediate and the deep waters, and (3) to calculate the resulting variation of pH (acidification) since the beginning of the industrial era. Since the calculation of CANT is always an intense subject of debate, we apply two radically different approaches to estimate CANT: the very simple method TrOCA and the MIX approach, the latter being more precise but also more difficult to apply. A clear picture for the AT and the CT distributions is obtained: the mean concentration of AT is higher in the oriental basin while that of CT is higher in the occidental basin of the Mediterranean Sea, fully coherent with the previous published works. Despite of the two very different approaches we use here (TrOCA and MIX), the estimated distributions of CANT are very similar. These distributions show that the minimum of CANT encountered during the BOUM cruise is higher than 46.3 μmol kg−1 (TrOCA) or 48.8 μmol kg−1(MIX). All Mediterranean water masses (even the deepest) appear to be highly contaminated by CANT, as a result of the very intense advective processes that characterize the recent history of the Mediterranean circulation. As a consequence, unprecedented levels of acidification are reached with an estimated decrease of pH since the pre-industrial era of −0.148 to −0.061 pH unit, which places the Mediterranean Sea as one of the most acidified world marine ecosystem.

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Along-Path Evolution of Biogeochemical and Carbonate System Properties in the Intermediate Water of the Western Mediterranean

Frontiers in Marine Science ◽

10.3389/fmars.2020.00375 ◽

2020 ◽

Vol 7 ◽

Author(s):

Katrin Schroeder ◽

Stefano Cozzi ◽

Malek Belgacem ◽

Mireno Borghini ◽

Carolina Cantoni ◽

...

Keyword(s):

Western Mediterranean ◽

Intermediate Water ◽

Carbonate System ◽

System Properties

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Analysis of Physical and Biogeochemical Control Mechanisms on Summertime Surface Carbonate System Variability in the Western Ross Sea (Antarctica) Using In Situ and Satellite Data

Remote Sensing ◽

10.3390/rs11030238 ◽

2019 ◽

Vol 11 (3) ◽

pp. 238 ◽

Cited By ~ 4

Author(s):

Paola Rivaro ◽

Carmela Ianni ◽

Lorenza Raimondi ◽

Clara Manno ◽

Silvia Sandrini ◽

...

Keyword(s):

Sea Ice ◽

Satellite Data ◽

Surface Waters ◽

Ross Sea ◽

Chlorophyll Concentration ◽

Control Mechanisms ◽

Carbonate System ◽

Basin Scale ◽

System Properties ◽

Western Ross Sea

In this study, carbonate system properties were measured in the western Ross Sea (Antarctica) over the 2005–2006 and 2011–2012 austral summers with the aim of analysing their sensitivity to physical and biogeochemical drivers. Daily Advanced Microwave Scanning Radiometer 2 (AMSR2) sea ice concentration maps, obtained prior to and during the samplings, were used to analyse the sea ice evolution throughout the experiment periods. Monthly means and 8-day composite chlorophyll concentration maps from the Moderate-resolution Imaging Spectroradiometer (MODIS) Aqua satellite at 4-km resolution were used to investigate inter-annual and basin scale biological variability. Chlorophyll-a concentrations in surface waters estimated by MODIS satellite data contribute to descriptions of the variability of carbonate system properties in surface waters. Mean values of carbonate system properties were comparable across both investigated years; however, the 2012 data displayed larger variability. Sea ice melting also had a pivotal role in controlling the carbonate system chemistry of the mixed layer both directly through dilution processes and indirectly by favouring the development of phytoplankton blooms. This resulted in high pH and ΩAr, and in low CT, particularly in those areas where high chlorophyll concentration was shown by satellite maps.

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The water column distribution of carbonate system variables at the ESTOC site from 1995 to 2004

Biogeosciences Discussions ◽

10.5194/bgd-7-1995-2010 ◽

2010 ◽

Vol 7 (2) ◽

pp. 1995-2032 ◽

Cited By ~ 1

Author(s):

M. González-Dávila ◽

J. M. Santana-Casiano ◽

M. J. Rueda ◽

O. Llinás

Keyword(s):

Carbon Dioxide ◽

Time Series ◽

North Atlantic ◽

Atmospheric Carbon Dioxide ◽

Inorganic Carbon ◽

Total Alkalinity ◽

Carbonate System ◽

Anthropogenic Co2 ◽

Atmospheric Carbon ◽

System Variables

Abstract. The accelerated rate of increase in the atmospheric carbon dioxide (CO2) and the substantial fraction of anthropogenic CO2 emissions absorbed by the oceans are affecting the anthropocenic properties of seawater. Long-term time series are a powerful tool for investigating any change in ocean bio-geochemistry and its effects on the carbon cycle. We have evaluated the ESTOC (European Station for Time series in the Ocean at the Canary islands) observations of measured pH (total scale at 25 °C) and total alkalinity plus computed total dissolved inorganic carbon CO2 concentration (CT) from 1995 to 2004 for surface and deep waters, by following all changes in response to increasing atmospheric carbon dioxide. The experimental values for the partial surface pressure of CO2 from 1995 to 2008 were also taken into consideration. The data were treated to better understand the fundamental processes controlling vertical distributions in the Eastern North Atlantic Ocean and the accumulation of anthropogenic CO2, CANT. CT at constant salinity, NCT, increased at a rate of 1 μmol kg−1 yr−1 in the first 200 m, linked to an fCO2 increase of 1.7±0.7 μatm yr−1 in both the atmosphere and the ocean. Consequently, the ESTOC site has also become more acidic, −0.0018±0.0003 units yr−1 over the first 100 m, whereas the carbonate ion concentrations and CaCO3 saturation states have also decreased over time. The rate of change is to be observed over the first 1000 m, where at 300, 600, and 1000 m the NCT increases at a rate of 0.69, 0.61 and 0.48 μmol kg−1 yr−1, respectively. The vertical distribution of the carbonate system variables are affected by the water mass structure and, to a different extent, controlled by the production/decomposition of organic matter, the formation/dissolution of carbonates, and differences in their respective pre-formed values. At 3000 m, 30% of the inorganic carbon production is related to the dissolution of calcium carbonate, with a total of 35% at the bottom. The total column inventory of anthropogenic CO2 for the decade was 66±3 mol m−2. A model fitting indicated that the column inventory of CANT increased from 61.7 mol m−2 in the year 1994 to 70.2 mol m−2 in 2004. The ESTOC site is presented by way of a reference site to follow CANT changes in the North Atlantic Sub-tropical gyre.

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Past and future evolution of the marine carbonate system in a coastal zone of the Northern Antarctic Peninsula

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/j.dsr2.2017.10.018 ◽

2018 ◽

Vol 149 ◽

pp. 193-205 ◽

Cited By ~ 7

Author(s):

Jannine M. Lencina-Avila ◽

Catherine Goyet ◽

Rodrigo Kerr ◽

Iole B.M. Orselli ◽

Mauricio M. Mata ◽

...

Keyword(s):

Coastal Zone ◽

Antarctic Peninsula ◽

Carbonate System ◽

Future Evolution ◽

Marine Carbonate

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Stable Carbon Isotopes of Phytoplankton as a Tool to Monitor Anthropogenic CO2 Submarine Leakages

Water ◽

10.3390/w12123573 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3573

Author(s):

Federica Relitti ◽

Nives Ogrinc ◽

Michele Giani ◽

Federica Cerino ◽

Mirta Smodlaka Smodlaka Tankovic ◽

...

Keyword(s):

Isotopic Composition ◽

Stable Carbon Isotopes ◽

Inorganic Carbon ◽

Dissolved Inorganic Carbon ◽

Carbon Isotopic Composition ◽

Stable Carbon ◽

Carbonate System ◽

Δ13c Values ◽

Carbon Isotopic ◽

Anthropogenic Co2

This study aims to validate the stable carbon isotopic composition (δ13C) of phytoplankton as a tool for detecting submarine leakages of anthropogenic CO2(g), since it is characterised by δ13C values significantly lower than the natural CO2 dissolved in oceans. Three culture experiments were carried out to investigate the changes in δ13C of the diatom Thalassiosira rotula during growth in an artificially modified medium (ASW). Three different dissolved inorganic carbon (DIC) concentrations were tested to verify if carbon availability affects phytoplankton δ13C. Simultaneously, at each experiment, T. rotula was cultured under natural DIC isotopic composition (δ13CDIC) and carbonate system conditions. The available DIC pool for diatoms grown in ASW was characterised by δ13CDIC values (−44.2 ± 0.9‰) significantly lower than the typical marine range. Through photosynthetic DIC uptake, microalgae δ13C rapidly changed, reaching significantly low values (until −43.4‰). Moreover, the different DIC concentrations did not affect the diatom δ13C, exhibiting the same trend in δ13C values in the three ASW experiments. The experiments prove that phytoplankton isotopic composition quickly responds to changes in the δ13C of the medium, making this approach a promising and low-impact tool for detecting CO2(g) submarine leakages from CO2(g) deposits.

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