OceanSODA-ETHZ: A global gridded data set of the surface ocean
carbonate system for seasonal to decadal studies of ocean
acidification

Gregor, Luke; Gruber, Nicolas

doi:10.5194/essd-2020-300

Cited by 33 publications

(51 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further, numerical modeling study focusing on the coastal upwelling region of California Current System has also reported a similar pH range (7.85-8.20) (Hauri et al, 2013). Model derived pH records available for our study region (Gregor & Gruber, 2021) (Figure 5b) and for the north-western Arabian Sea (Sreeush et al, 2019) are characterized by long-term declining trend with much smaller pH variability. Whereas our δ 11 B coral derived pH record shows much larger pH variability with no discernable decreasing trend (Figure 5a) highlighting divergence between the proxy based reconstruction and numerical model simulations of the past pH.…”

Section: Resultssupporting

confidence: 74%

“…This short and discrete record of BOBOA is insufficient to quantify OA rates and to decipher any long-term OA trend in the Indian Ocean. The lack of instrumental and proxy based pH data leads to a dependency on calculation or model-based estimation of pH change for this region (Gregor & Gruber, 2021;Jiang et al, 2019;Joshi et al, 2020;Sreeush et al, 2019;Valsala et al, 2021;Xue et al, 2014). Thus, the regional and global scale forcing factors that can potentially influence the amplitude and frequency of pH changes in the Indian Ocean need to be recognized and to quantify their relative roles.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Surface pH Record (1990–2013) of the Arabian Sea From Boron Isotopes of Lakshadweep Corals—Trend, Variability, and Control

et al. 2021

View full text Add to dashboard Cite

Approximately 30% of the anthropogenic CO 2 emission has been absorbed by the oceans (Friedlingstein et al., 2019;Sabine & Tanhua, 2010). The CO 2 invasion to the oceans since the industrial revolution (∼1850) has caused a decrease of ∼0.1 unit in surface ocean pH, a process commonly known as ocean acidification (OA) (Doney et al., 2009). Numerical model simulations for the end of the century at different scenarios of Abstract Atmospheric CO 2 rise in post-industrial era has resulted in decline in surface ocean pH, commonly known as "ocean acidification (OA)," which has become a threat to marine calcifiers. Instrumental records of ocean pH and its reconstruction utilizing boron isotope (δ 11 B) composition of corals demonstrate a long-term OA trend characterized by large spatio-temporal variability in both Pacific and Atlantic oceans. However, no such record exists to elucidate long-term OA trend of the Indian Ocean. We report the first sub-annually resolved pH record from the Arabian Sea based on δ 11 B measurements on Porites coral from Lakshadweep coral reefs. This pH record is characterized by large variability ranging from 7.93 to 8.65 with no long-term discernable trend. The long-term declining trend expected from the ∼50 ppm increase in atmospheric CO 2 during the coral growth interval appears to be obscured by large surface pH variability in the Arabian Sea. Our investigation reveals that physical oceanographic processes for example, upwelling, downwelling and convective mixing modulated by El Niño-Southern Oscillation (ENSO) largely control surface pH variability and masked expected long-term OA trend resulting from anthropogenic CO 2 rise. Combining the model-based predictions of increase in frequency and amplitude of ENSO events in a future warming scenario and the observed ENSO dependency of surface water pH, we predict more frequent and large pH variability ("pH extremes") in this region. Such pH extremes and their occurrences might be critical for the resilience and adaptability of corals and other calcifiers in Arabian Sea and other similar oceanic settings elsewhere.Plain Language Summary Increase in the atmospheric CO 2 concentration since the industrial revolution (∼1850) has resulted in decrease in ocean pH, known as ocean acidification (OA). Only limited number of pH records are avalable to assess the impacts of OA on marine ecosystems. The available pH records from the Pacific and Atlantic oceans, based on both instrumental observations and coral boron isotope records, demonstrate a long-term declining trend with significant internal variability. However, no such records are available from the Indian Ocean. Here, we provide the first seasonally resolved record of Indian Ocean pH for a 23 year period based on boron isotope study of corals collected from the Lakshadweep, Arabian Sea. pH variability in the Arabian Sea is domiantly controlled by ENSO modulated oceanographic processes such as upwelling and mixing. We did not observe any long-term declining trend corresponding to the ∼50 ppm rise...

show abstract

Section: Resultssupporting

confidence: 74%

mentioning

confidence: 99%

Surface pH Record (1990–2013) of the Arabian Sea From Boron Isotopes of Lakshadweep Corals—Trend, Variability, and Control

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The CanESM5 control ensemble is capable of capturing the phasing and magnitude in the climatological seasonal cycle of ΔpCO 2 as measured at the Woods Hole Oceanographic Institution Hawaii Ocean Timeseries Site (WHOTS) buoy, though the spring minimum is deeper in approximately half of the CanESM ensemble members than observed ( Figure S1b). While the annual mean surface ocean pH over 2015-2018 exhibits similar spatial patterns between modeled pH and an observation-based product (Gregor & Gruber, 2020), the modeled pH is generally lower than that from observation-based estimates ( Figure S2). As with ΔpCO 2 , a lack of observation-based climatological estimates of pH in the seasonally ice covered Southern Ocean and Arctic precludes investigation of model-observation similarity in these regions.…”

Section: 1029/2020gl092263mentioning

confidence: 74%

The Ocean Carbon Response to COVID‐Related Emissions Reductions

Lovenduski

Swart

Sutton

et al. 2021

Geophysical Research Letters

View full text Add to dashboard Cite

The socioeconomic disruptions associated with the COVID-19 pandemic have caused an unprecedented drop in global emissions of carbon dioxide (CO 2) and other atmospheric pollutants. The year 2020 was characterized by a 6.4% decrease in global CO 2 emissions relative to the previous year (Carbon Monitor Project, 2021; Liu et al., 2020), with average daily emissions declines peaking at −26% in individual countries (Le Quéré et al., 2020). The duration and severity of the emissions decline in the future is as yet unknown, but anomalously low CO 2 emissions are also expected in 2021 (Liu et al., 2020). The important role of CO 2 emissions in the global carbon cycle and climate system motivates further research on this topic. Several research groups are actively studying the impact of the COVID-related emissions reductions on the atmosphere and climate system. The latest World Meteorological Organization bulletin reports slight reductions in 2020 atmospheric CO 2 levels (−0.08 to −0.23 ppm) as a result of the COVID pandemic, though they emphasize that this reduction is difficult to detect given typical year-to-year variations in atmospheric CO 2 (± 1 ppm; World Meteorological Organization, 2020). A recent modeling study concurs that COVID-related reductions in atmospheric CO 2 levels are likely undetectable, but also demonstrates that these short-term

show abstract

“…Software for the GRaCER framework is available on Zenodo https://doi.org/10.5281/zenodo.4455354 (Gregor, 2021). The OceanSODA-ETHZ data set is available at https://doi.org/10.25921/m5wx-ja34 (Gregor and Gruber, 2020).…”

Section: Code and Data Availabilitymentioning

confidence: 99%

OceanSODA-ETHZ: a global gridded data set of the surface ocean carbonate system for seasonal to decadal studies of ocean acidification

Gregor

Gruber

2021

Earth Syst. Sci. Data

Self Cite

137

116

View full text Add to dashboard Cite

Abstract. Ocean acidification has profoundly altered the ocean's carbonate chemistry since preindustrial times, with potentially serious consequences for marine life. Yet, no long-term, global observation-based data set exists that allows us to study changes in ocean acidification for all carbonate system parameters over the last few decades. Here, we fill this gap and present a methodologically consistent global data set of all relevant surface ocean parameters, i.e., dissolved inorganic carbon (DIC), total alkalinity (TA), partial pressure of CO2 (pCO2), pH, and the saturation state with respect to mineral CaCO3 (Ω) at a monthly resolution over the period 1985 through 2018 at a spatial resolution of 1∘×1∘. This data set, named OceanSODA-ETHZ, was created by extrapolating in time and space the surface ocean observations of pCO2 (from the Surface Ocean CO2 Atlas, SOCAT) and total alkalinity (TA; from the Global Ocean Data Analysis Project, GLODAP) using the newly developed Geospatial Random Cluster Ensemble Regression (GRaCER) method (code available at https://doi.org/10.5281/zenodo.4455354, Gregor, 2021). This method is based on a two-step (cluster-regression) approach but extends it by considering an ensemble of such cluster regressions, leading to improved robustness. Surface ocean DIC, pH, and Ω were then computed from the globally mapped pCO2 and TA using the thermodynamic equations of the carbonate system. For the open ocean, the cluster-regression method estimates pCO2 and TA with global near-zero biases and root mean squared errors of 12 µatm and 13 µmol kg−1, respectively. Taking into account also the measurement and representation errors, the total uncertainty increases to 14 µatm and 21 µmol kg−1, respectively. We assess the fidelity of the computed parameters by comparing them to direct observations from GLODAP, finding surface ocean pH and DIC global biases of near zero, as well as root mean squared errors of 0.023 and 16 µmol kg−1, respectively. These uncertainties are very comparable to those expected by propagating the total uncertainty from pCO2 and TA through the thermodynamic computations, indicating a robust and conservative assessment of the uncertainties. We illustrate the potential of this new data set by analyzing the climatological mean seasonal cycles of the different parameters of the surface ocean carbonate system, highlighting their commonalities and differences. Further, this data set provides a novel constraint on the global- and basin-scale trends in ocean acidification for all parameters. Concretely, we find for the period 1990 through 2018 global mean trends of 8.6 ± 0.1 µmol kg−1 per decade for DIC, −0.016 ± 0.000 per decade for pH, 16.5 ± 0.1 µatm per decade for pCO2, and −0.07 ± 0.00 per decade for Ω. The OceanSODA-ETHZ data can be downloaded from https://doi.org/10.25921/m5wx-ja34 (Gregor and Gruber, 2020).

show abstract

OceanSODA-ETHZ: A global gridded data set of the surface ocean carbonate system for seasonal to decadal studies of ocean acidification

Cited by 33 publications

References 61 publications

Surface pH Record (1990–2013) of the Arabian Sea From Boron Isotopes of Lakshadweep Corals—Trend, Variability, and Control

Surface pH Record (1990–2013) of the Arabian Sea From Boron Isotopes of Lakshadweep Corals—Trend, Variability, and Control

The Ocean Carbon Response to COVID‐Related Emissions Reductions

OceanSODA-ETHZ: a global gridded data set of the surface ocean carbonate system for seasonal to decadal studies of ocean acidification

Contact Info

Product

Resources

About