Simultaneous CO 2 and O 2 supersaturation in waters of Southern Patagonia?: The importance of evaluating overall carbonate system parameters uncertainty and external consistency. A comment to Vargas et al., 2018.

Abstract. Ocean acidification driven by the uptake of anthropogenic CO2 by the surface oceans constitutes a potential threat to the health of marine ecosystems around the globe. The Arctic Ocean is particularly vulnerable to acidification and thus is an ideal region to study the progression and effects of acidification before they become globally widespread. The appearance of undersaturated surface waters with respect to the carbonate mineral aragonite (ΩA<1), an important threshold beyond which the calcification and growth of some marine organisms might be hindered, has recently been documented in the Canada Basin and adjacent Canadian Arctic Archipelago (CAA), a dynamic region with an inherently strong variability in biogeochemical processes. Nonetheless, few of these observations were made in the last 5 years and the spatial coverage in the latter region is poor. We use a dataset of carbonate system parameters measured in the CAA and its adjacent basins (Canada Basin and Baffin Bay) from 2003 to 2016 to describe the recent state of these parameters across the Canadian Arctic and investigate the amplitude and sources of the system's variability over more than a decade. Our findings reveal that, in the summers of 2014 to 2016, the ocean surface across our study area served as a net CO2 sink and was partly undersaturated with respect to aragonite in the Canada Basin and the Queen Maud Gulf, the latter region exhibiting undersaturation over its entire water column at some locations. We estimate, using measurements made across several years, that approximately a third of the interannual variability in surface dissolved inorganic carbon (DIC) concentrations in the CAA results from fluctuations in biological activity. In consideration of the system's variability resulting from these fluctuations, we derive times of emergence of the anthropogenic ocean acidification signal for carbonate system parameters in the study area.

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Winter mesoscale variations of carbonate system parameters and estimates of CO2fluxes in the Gulf of Cadiz, northeast Atlantic Ocean (February 1998)

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jc001243 ◽

2003 ◽

Vol 108 (C11) ◽

Cited By ~ 15

Author(s):

Melchor González-Dávila ◽

J. Magdalena Santana-Casiano ◽

Evgeny V. Dafner

Keyword(s):

Atlantic Ocean ◽

Gulf Of Cadiz ◽

Carbonate System ◽

Northeast Atlantic ◽

System Parameters ◽

Gulf Of Cádiz ◽

Northeast Atlantic Ocean

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Interannual variability of air-sea CO<sub>2</sub> fluxes and carbonate system parameters in the East Siberian Sea

Biogeosciences Discussions ◽

10.5194/bgd-8-1227-2011 ◽

2011 ◽

Vol 8 (1) ◽

pp. 1227-1273 ◽

Cited By ~ 4

Author(s):

I. I. Pipko ◽

I. P. Semiletov ◽

S. P. Pugach ◽

I. Wåhlström ◽

L. G. Anderson

Keyword(s):

Organic Matter ◽

Primary Production ◽

Coastal Erosion ◽

Atmospheric Co2 ◽

The Arctic ◽

Co2 Fluxes ◽

Carbonate System ◽

System Parameters ◽

East Siberian Sea ◽

Air Exchange

Abstract. Over the past couple of decades it has become apparent that air-land-sea interactions in the Arctic have a substantial impact on the composition of the overlying atmosphere (ACIA, 2004). The Arctic Ocean is small (only ~4% of the total World Ocean), but it is surrounded by offshore and onshore permafrost which thaws at increasing rates under warming conditions releasing carbon dioxide (CO2) into the water and atmosphere. This work summarizes data collected from three expeditions in the coastal-shelf zone of the East Siberian Sea (ESS) in September 2003, 2004 and late August–September 2008. It is proposed that the western part of the ESS represents a river- and coastal erosion-dominated ocean margin that is a source for atmospheric CO2. It receives substantial river discharge that also adds organic matter, both dissolved and particulate. This in combination with significant input of organic matter from coastal erosion makes this region being of dominantly heterotrophic character. The eastern part of the ESS is a Pacific water-dominated autotrophic area. It's a high-productive zone, which acts as a sink for atmospheric CO2. The year to year dynamics of partial pressure of CO2 in the surface water as well as the sea-air flux of CO2 varied substantially. In some years the ESS shelf can be mainly heterotrophic and serve as strong source of CO2 (year 2004). Another year significant part of the ESS, where gross primary production exceeds community respiration, acts as a sink for the atmospheric CO2 and the net CO2 flux into the atmosphere is weak (year 2008). High variability of carbon system parameters observed in the ESS shelf is determined by many factors such as riverine runoff, advection of waters from adjacent seas, coastal erosion, primary production/respiration etc. The dynamics of the CO2 sea-air exchange is determined by ocean processes but also by atmospheric circulation which hence has a significant impact on the CO2 sea-air exchange. In this contribution the sea-air CO2 fluxes were evaluated in the ESS based on measured carbonate system (CS) parameters data and annual sea-to-air CO2 fluxes were estimated. It was shown that the total ESS shelf is a net source of CO2 for the atmosphere at a range from 0.5×1012 to 3.3×1012 g C.

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Estimates of Water-Column Nutrient Concentrations and Carbonate System Parameters in the Global Ocean: A Novel Approach Based on Neural Networks

Frontiers in Marine Science ◽

10.3389/fmars.2017.00128 ◽

2017 ◽

Vol 4 ◽

Cited By ~ 32

Author(s):

Raphaëlle Sauzède ◽

Henry C. Bittig ◽

Hervé Claustre ◽

Orens Pasqueron de Fommervault ◽

Jean-Pierre Gattuso ◽

...

Keyword(s):

Neural Networks ◽

Water Column ◽

Global Ocean ◽

Nutrient Concentrations ◽

Carbonate System ◽

System Parameters ◽

Novel Approach ◽

Water Column Nutrient

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Decoupled carbonate chemistry controls on the incorporation of boron into <i>Orbulina universa</i>

Biogeosciences ◽

10.5194/bg-14-415-2017 ◽

2017 ◽

Vol 14 (2) ◽

pp. 415-430 ◽

Cited By ~ 18

Author(s):

Ella L. Howes ◽

Karina Kaczmarek ◽

Markus Raitzsch ◽

Antje Mewes ◽

Nienke Bijma ◽

...

Keyword(s):

Isotopic Composition ◽

Inductively Coupled Plasma ◽

Culture Media ◽

Boron Uptake ◽

Carbonate System ◽

Ample Evidence ◽

System Parameters ◽

Effects Of Ph ◽

Orbulina Universa ◽

Primary Relationship

Abstract. In order to fully constrain paleo-carbonate systems, proxies for two out of seven parameters, plus temperature and salinity, are required. The boron isotopic composition (δ11B) of planktonic foraminifera shells is a powerful tool for reconstructing changes in past surface ocean pH. As B(OH)4− is substituted into the biogenic calcite lattice in place of CO32−, and both borate and carbonate ions are more abundant at higher pH, it was suggested early on that B ∕ Ca ratios in biogenic calcite may serve as a proxy for [CO32−]. Although several recent studies have shown that a direct connection of B ∕ Ca to carbonate system parameters may be masked by other environmental factors in the field, there is ample evidence for a mechanistic relationship between B ∕ Ca and carbonate system parameters. Here, we focus on investigating the primary relationship to develop a mechanistic understanding of boron uptake. Differentiating between the effects of pH and [CO32−] is problematic, as they co-vary closely in natural systems, so the major control on boron incorporation remains unclear. To deconvolve the effects of pH and [CO32−] and to investigate their impact on the B ∕ Ca ratio and δ11B, we conducted culture experiments with the planktonic foraminifer Orbulina universa in manipulated culture media: constant pH (8.05), but changing [CO32−] (238, 286 and 534 µmol kg−1 CO32−) and at constant [CO32−] (276 ± 19.5 µmol kg−1) and varying pH (7.7, 7.9 and 8.05). Measurements of the isotopic composition of boron and the B ∕ Ca ratio were performed simultaneously using a femtosecond laser ablation system coupled to a MC-ICP-MS (multiple-collector inductively coupled plasma mass spectrometer). Our results show that, as expected, δ11B is controlled by pH but it is also modulated by [CO32−]. On the other hand, the B ∕ Ca ratio is driven by [HCO3−], independently of pH. This suggests that B ∕ Ca ratios in foraminiferal calcite can possibly be used as a second, independent, proxy for complete paleo-carbonate system reconstructions. This is discussed in light of recent literature demonstrating that the primary relationship between B ∕ Ca and [HCO3−] can be obscured by other environmental parameters.

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