GLODAPv2.2019 – an update of GLODAPv2

Olsen, Are; Lange, Nico; Key, Robert M.; Tanhua, Toste; Álvarez, Marta; Becker, Susan; Bittig, Henry C.; Carter, Brendan R.; Cunha, Letícia Cotrim da; Feely, Richard A.; Heuven, Steven van; Hoppema, Mario; Ishii, Masao; Jeansson, Emil; Jones, Steve; Jütterström, Sara; Karlsen, Maren K.; Kozyr, Alex; Lauvset, Siv K.; Monaco, Claire Lo; Murata, Akihiko; Pérez, Fíz F.; Pfeil, Benjamin; Schirnick, Carsten; Steinfeldt, Reiner; Suzuki, T.; Telszewski, Maciej; Tilbrook, Bronte; Velo, A.; Wanninkhof, Rik

doi:10.5194/essd-11-1437-2019

Cited by 148 publications

(164 citation statements)

References 80 publications

(105 reference statements)

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“…The baseline value from which the various pH perturbations are estimated is pH 2002 , which is calculated from the observed total alkalinity (TA) and dissolved inorganic carbon (DIC) in GLODAPv2 (Olsen et al, ), where DIC is first adjusted to year 2002 using the atmospheric perturbation method as detailed in Appendix B of Lauvset et al (), and the assumption that TA does not change over time. Since few ship‐based observations of ocean carbonate chemistry are made in winter there is a recognized seasonal bias in the GLODAPv2 data product (Olsen et al, ), and hence in all calculations made using these data, which makes the data product challenging to use for the surface ocean. No attempt has been made to correct for this bias in this present work, although we note that this bias is primarily an issue for surface measurements and this analysis focuses on the ocean interior.…”

Section: Methodsmentioning

confidence: 99%

Processes Driving Global Interior Ocean pH Distribution

Lauvset

Carter

Pérez

et al. 2020

Global Biogeochemical Cycles

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Ocean acidification evolves on the background of a natural ocean pH gradient that is the result of the interplay between ocean mixing, biological production and remineralization, calcium carbonate cycling, and temperature and pressure changes across the water column. While previous studies have analyzed these processes and their impacts on ocean carbonate chemistry, none have attempted to quantify their impacts on interior ocean pH globally. Here we evaluate how anthropogenic changes and natural processes collectively act on ocean pH, and how these processes set the vulnerability of regions to future changes in ocean acidification. We use the mapped data product from the Global Ocean Data Analysis Project version 2, a novel method to estimate preformed total alkalinity based on a combination of a total matrix intercomparison and locally interpolated regressions, and a comprehensive uncertainty analysis. We find that the largest contribution to the interior ocean pH gradient comes from organic matter remineralization, with CaCO 3 cycling being the second most important process. The estimates of the impact of anthropogenic CO 2 changes on pH reaffirm the large and well-understood anthropogenic impact on pH in the surface ocean, and put it in the context of the natural pH gradient in the interior ocean. We also show that in the depth layer 500-1,500 m natural processes enhance ocean acidification by on average 28 ± 15%, but with large regional gradients.

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Section: Methodsmentioning

confidence: 99%

Processes Driving Global Interior Ocean pH Distribution

Lauvset

Carter

Pérez

et al. 2020

Global Biogeochemical Cycles

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“…The red dot is IODP Site U1305. The section on the right is dissolved oxygen from GLODAPv2.2019 (Olsen et al, 2019) and is indicated on the map on the left by the red polygon. Major water masses Antarctic Bottom Water (AABW), Circumpolar Deep Water (CDW), and North Atlantic Deep Water (NADW) are indicated in the section.…”

Section: Introductionmentioning

confidence: 99%

Changes in Antarctic Bottom Water Formation During Interglacial Periods

Glasscock

Hayes

Redmond

et al. 2020

Paleoceanog and Paleoclimatol

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In the modern Southern Ocean and during the last interglacial period, Marine Isotope Stage 5e, there are observations that point to reduced Antarctic Bottom Water (AABW) formation. These reductions are believed to be driven by an increase in the strength of the Southern Ocean density stratification due to Antarctic ice melt‐induced surface water freshening. Any reduction in AABW formation has important implications for global climate as AABW plays a vital role in the cycling of carbon in the world's ocean. The primary question this study seeks to answer is do these AABW reductions occur during any of the other interglacials of the past 470,000 years? To study AABW changes in the paleoceanographic record, we look at changes in the redox record. Newly formed AABW is oxygen‐rich, so any reduction should lead to a decrease in oxygen concentrations in the deep Southern Ocean. The trace element uranium is useful for studying these redox changes as it is enriched in marine sediments under low‐oxygen conditions. When accounting for other factors, such as paleoproductivity, that can also decrease the oxygen concentrations in sedimentary porewater, it is possible to identify changes in AABW using authigenic uranium. The survey conducted by this study found a possible AABW reduction during late Marine Isotope Stage 11 (~397 ka). The cause of this event is less clear than others studied, and we explore the possibilities of ice melt‐induced freshening or a change in the position or strength of the Southern Hemisphere westerly winds.

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“…The pH values were reported on total pH scale at 0 dbar of pressure and both at 25ºC and in situ temperature following the same procedure of GLODAP v2 (Olsen et al, 2019). A total of 12,220 measurements of pH on NBS scale were converted to the total scale using CO2SYS (Lewis and Wallace, 1998) for MATLAB (van Heuven et al, 2011) with pH and total alkalinity as inputs.…”

Section: Ph Measurementsmentioning

confidence: 99%

ARIOS: An acidification ocean database for the Iberian Upwelling Ecosystem (1976–2018)

Pad́ın

Velo

Pérez

2020

Preprint

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Abstract. A data product of 17,653 discrete samples from 3,357 oceanographic stations combining measurements of pH, alkalinity and other biogeochemical parameters off the North-western Iberian Peninsula from June 1976 to September 2018 is presented in this study. The oceanography cruises funded by 24 projects were primarily carried out in the Ría de Vigo coastal inlet, but also in an area ranging from the Bay of Biscay to the Portuguese coast. The robust seasonal cycles and long-term trends were only calculated along a longitudinal section, gathering data from the coastal and oceanic zone of the Iberian Upwelling System. The pH in the surface waters of these separated regions, which were highly variable due to intense photosynthesis and the remineralization of organic matter, showed an interannual acidification ranging from −0.0016 yr−1 to −0.0032 yr−1 that grew towards the coastline. This result is obtained despite the buffering capacity increasing in the coastal waters further inland as shown by the increase in alkalinity by 1.1±0.7 μmol kg−1 yr−1 and 2.6±1.0 μmol kg−1 yr−1 in the inner and outer Ría de Vigo respectively, driven by interannual changes in the surface salinity of 0.0193±0.0056 psu yr−1 and 0.0426±0.016 psu yr−1 respectively. The loss of the vertical salinity gradient in the long-term trend in the inner ria was consistent with other significant biogeochemical changes such as a lower oxygen concentration and fertilization of the surface waters. These findings seem to be related to a growing footprint of sediment remineralization of organic matter in the surface layer of a more homogeneous water column. Data are available at: https://doi.org/10.20350/digitalCSIC/12498 (Pérez et al., 2020).

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GLODAPv2.2019 – an update of GLODAPv2

Cited by 148 publications

References 80 publications

Processes Driving Global Interior Ocean pH Distribution

Processes Driving Global Interior Ocean pH Distribution

Changes in Antarctic Bottom Water Formation During Interglacial Periods

ARIOS: An acidification ocean database for the Iberian Upwelling Ecosystem (1976–2018)

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