Cai Wei-Jun

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Using present-day observations to detect when anthropogenic change forces surface ocean carbonate chemistry outside preindustrial bounds

(Copernicus Publications on behalf of the European Geosciences Union, 2016-09-13) Sutton, Adrienne J. ; Sabine, Chris L. ; Feely, Richard A. ; Cai, Wei-Jun ; Cronin, Meghan F. ; McPhaden, Michael J. ; Morell, Julio M. ; Newton, Jan A. ; Noh, Jae Hoon ; Ólafsdóttir, Sólveig R. ; Salisbury, Joseph E. ; Send, Uwe ; Vandemark, Douglas ; Weller, Robert A.

One of the major challenges to assessing the impact of ocean acidification on marine life is detecting and interpreting long-term change in the context of natural variability. This study addresses this need through a global synthesis of monthly pH and aragonite saturation state (Ωarag) climatologies for 12 open ocean, coastal, and coral reef locations using 3-hourly moored observations of surface seawater partial pressure of CO2 and pH collected together since as early as 2010. Mooring observations suggest open ocean subtropical and subarctic sites experience present-day surface pH and Ωarag conditions outside the bounds of preindustrial variability throughout most, if not all, of the year. In general, coastal mooring sites experience more natural variability and thus, more overlap with preindustrial conditions; however, present-day Ωarag conditions surpass biologically relevant thresholds associated with ocean acidification impacts on Mytilus californianus (Ωarag < 1.8) and Crassostrea gigas (Ωarag < 2.0) larvae in the California Current Ecosystem (CCE) and Mya arenaria larvae in the Gulf of Maine (Ωarag < 1.6). At the most variable mooring locations in coastal systems of the CCE, subseasonal conditions approached Ωarag =  1. Global and regional models and data syntheses of ship-based observations tended to underestimate seasonal variability compared to mooring observations. Efforts such as this to characterize all patterns of pH and Ωarag variability and change at key locations are fundamental to assessing present-day biological impacts of ocean acidification, further improving experimental design to interrogate organism response under real-world conditions, and improving predictive models and vulnerability assessments seeking to quantify the broader impacts of ocean acidification.
Autonomous seawater pCO2 and pH time series from 40 surface buoys and the emergence of anthropogenic trends

(Copernicus Publications, 2019-03-26) Sutton, Adrienne J. ; Feely, Richard A. ; Maenner-Jones, Stacy ; Musielwicz, Sylvia ; Osborne, John ; Dietrich, Colin ; Monacci, Natalie ; Cross, Jessica N. ; Bott, Randy ; Kozyr, Alex ; Andersson, Andreas J. ; Bates, Nicholas R. ; Cai, Wei-Jun ; Cronin, Meghan F. ; De Carlo, Eric H. ; Hales, Burke ; Howden, Stephan D. ; Lee, Charity M. ; Manzello, Derek P. ; McPhaden, Michael J. ; Meléndez, Melissa ; Mickett, John B. ; Newton, Jan A. ; Noakes, Scott ; Noh, Jae Hoon ; Olafsdottir, Solveig R. ; Salisbury, Joseph E. ; Send, Uwe ; Trull, Thomas W. ; Vandemark, Douglas ; Weller, Robert A.

Ship-based time series, some now approaching over 3 decades long, are critical climate records that have dramatically improved our ability to characterize natural and anthropogenic drivers of ocean carbon dioxide (CO2) uptake and biogeochemical processes. Advancements in autonomous marine carbon sensors and technologies over the last 2 decades have led to the expansion of observations at fixed time series sites, thereby improving the capability of characterizing sub-seasonal variability in the ocean. Here, we present a data product of 40 individual autonomous moored surface ocean pCO2 (partial pressure of CO2) time series established between 2004 and 2013, 17 also include autonomous pH measurements. These time series characterize a wide range of surface ocean carbonate conditions in different oceanic (17 sites), coastal (13 sites), and coral reef (10 sites) regimes. A time of trend emergence (ToE) methodology applied to the time series that exhibit well-constrained daily to interannual variability and an estimate of decadal variability indicates that the length of sustained observations necessary to detect statistically significant anthropogenic trends varies by marine environment. The ToE estimates for seawater pCO2 and pH range from 8 to 15 years at the open ocean sites, 16 to 41 years at the coastal sites, and 9 to 22 years at the coral reef sites. Only two open ocean pCO2 time series, Woods Hole Oceanographic Institution Hawaii Ocean Time-series Station (WHOTS) in the subtropical North Pacific and Stratus in the South Pacific gyre, have been deployed longer than the estimated trend detection time and, for these, deseasoned monthly means show estimated anthropogenic trends of 1.9±0.3 and 1.6±0.3 µatm yr−1, respectively. In the future, it is possible that updates to this product will allow for the estimation of anthropogenic trends at more sites; however, the product currently provides a valuable tool in an accessible format for evaluating climatology and natural variability of surface ocean carbonate chemistry in a variety of regions. Data are available at https://doi.org/10.7289/V5DB8043 and https://www.nodc.noaa.gov/ocads/oceans/Moorings/ndp097.html (Sutton et al., 2018).
High pressure liquid chromatography analyses of photosynthetic pigments taken on the R/V Acadian and R/V Pelican from September to October 2017 in the Central northern Gulf of Mexico

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-02-07) Lohrenz, Steven ; Chakraborty, Sumit ; Cai, Wei-Jun

High pressure liquid chromatography analyses of photosynthetic pigments taken on the R/V Acadian and R/V Pelican from September to October 2017 in the Central northern Gulf of Mexico. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/789061
DIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April 2017

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-07-11) Cai, Wei-Jun ; Rabalais, Nancy ; Fennel, Katja

Dissolved inorganic carbon, total alkalinity and pH from an R/V Pelican cruise conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W ) from April 5th to 16th, 2017. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/772513
DIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April and July 2017

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-01-28) Cai, Wei-Jun ; Rabalais, Nancy ; Fennel, Katja

Dissolved inorganic carbon, total alkalinity and pH from R/V Pelican cruises conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W ) from April 5 to 16 and July 7 to 21 in 2017 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/772513
And on top of all that… coping with ocean acidification in the midst of many stressors

(The Oceanography Society, 2015-06) Breitburg, Denise L. ; Salisbury, Joseph E. ; Bernhard, Joan M. ; Cai, Wei-Jun ; Dupont, Sam ; Doney, Scott C. ; Kroeker, Kristy J. ; Levin, Lisa A. ; Long, W. Christopher ; Milke, Lisa M. ; Miller, Seth H. ; Phelan, Beth ; Passow, Uta ; Seibel, Brad A. ; Todgham, Anne E. ; Tarrant, Ann M.

Oceanic and coastal waters are acidifying due to processes dominated in the open ocean by increasing atmospheric CO2 and dominated in estuaries and some coastal waters by nutrient-fueled respiration. The patterns and severity of acidification, as well as its effects, are modified by the host of stressors related to human activities that also influence these habitats. Temperature, deoxygenation, and changes in food webs are particularly important co-stressors because they are pervasive, and both their causes and effects are often mechanistically linked to acidification. Development of a theoretical underpinning to multiple stressor research that considers physiological, ecological, and evolutionary perspectives is needed because testing all combinations of stressors and stressor intensities experimentally is impossible. Nevertheless, use of a wide variety of research approaches is a logical and promising strategy for improving understanding of acidification and its effects. Future research that focuses on spatial and temporal patterns of stressor interactions and on identifying mechanisms by which multiple stressors affect individuals, populations, and ecosystems is critical. It is also necessary to incorporate consideration of multiple stressors into management, mitigation, and adaptation to acidification and to increase public and policy recognition of the importance of addressing acidification in the context of the suite of other stressors with which it potentially interacts.
Underway pCO2 from the R/V Pelican cruise GOM_UW_1704 conducted in the Northern Gulf of Mexico in April 2017.

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-07-10) Cai, Wei-Jun ; Rabalais, Nancy ; Fennel, Katja

Underway pCO2 from R/V Pelican cruise conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W) from April 5th to 16th in 2017. The precision of pCO2 is ±2 µatm. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/770864
The marine inorganic carbon system along the Gulf of Mexico and Atlantic coasts of the United States : insights from a transregional coastal carbon study

(Association for the Sciences of Limnology and Oceanography, 2013-01) Wang, Zhaohui Aleck ; Wanninkhof, Rik ; Cai, Wei-Jun ; Byrne, Robert H. ; Hu, Xinping ; Peng, Tsung-Hung ; Huang, Wei-Jen

Distributions of total alkalinity (TA), dissolved inorganic carbon (DIC), and other parameters relevant to the marine inorganic carbon system were investigated in shelf and adjacent ocean waters during a U.S. Gulf of Mexico and East Coast Carbon cruise in July–August 2007. TA exhibited near-conservative behavior with respect to salinity. Shelf concentrations were generally high in southern waters (Gulf of Mexico and East Florida) and decreased northward from Georgia to the Gulf of Maine. DIC was less variable geographically and exhibited strongly nonconservative behavior. As a result, the ratio of TA to DIC generally decreased northward. The spatial patterns of other CO2 system parameters closely followed those of the TA : DIC ratio. All sampled shelf waters were supersaturated with respect to aragonite (saturation state ΩA > 1). The most intensely buffered and supersaturated waters (ΩA > 5.0) were in northern Gulf of Mexico river-plume waters; the least intensely buffered and least supersaturated waters (ΩA < 1.3) were in the deep Gulf of Maine. Due to their relatively low pH, ΩA, and buffer intensity, waters of the northeastern U.S. shelves may be more susceptible to acidification pressures than are their southern counterparts. In the Mid-Atlantic Bight, alongshore mixing tended to increase DIC concentrations southward, but this effect was largely offset by the opposing effects of biogeochemical processing. In the Gulf of Mexico, downstream increases in Loop Current DIC suggested significant contributions from shelf and gulf waters, estimated at 9.1 × 109 mol C d−1. Off the southeastern U.S., along-flow chemical changes in the Florida Current were dominated by mixing associated with North Atlantic subtropical recirculation.
Surface ocean pCO2 seasonality and sea-air CO2 flux estimates for the North American east coast

(John Wiley & Sons, 2013-10-16) Signorini, Sergio R. ; Mannino, Antonio ; Najjar, Raymond G. ; Friedrichs, Marjorie A. M. ; Cai, Wei-Jun ; Salisbury, Joseph E. ; Wang, Zhaohui Aleck ; Thomas, Helmuth ; Shadwick, Elizabeth H.

Underway and in situ observations of surface ocean pCO2, combined with satellite data, were used to develop pCO2 regional algorithms to analyze the seasonal and interannual variability of surface ocean pCO2 and sea-air CO2 flux for five physically and biologically distinct regions of the eastern North American continental shelf: the South Atlantic Bight (SAB), the Mid-Atlantic Bight (MAB), the Gulf of Maine (GoM), Nantucket Shoals and Georges Bank (NS+GB), and the Scotian Shelf (SS). Temperature and dissolved inorganic carbon variability are the most influential factors driving the seasonality of pCO2. Estimates of the sea-air CO2 flux were derived from the available pCO2 data, as well as from the pCO2 reconstructed by the algorithm. Two different gas exchange parameterizations were used. The SS, GB+NS, MAB, and SAB regions are net sinks of atmospheric CO2 while the GoM is a weak source. The estimates vary depending on the use of surface ocean pCO2 from the data or algorithm, as well as with the use of the two different gas exchange parameterizations. Most of the regional estimates are in general agreement with previous studies when the range of uncertainty and interannual variability are taken into account. According to the algorithm, the average annual uptake of atmospheric CO2 by eastern North American continental shelf waters is found to be between −3.4 and −5.4 Tg C yr−1 (areal average of −0.7 to −1.0 mol CO2 m−2 yr−1) over the period 2003–2010.
A science plan for carbon cycle research in North American coastal waters. Report of the Coastal CARbon Synthesis (CCARS) community workshop, August 19-21, 2014

(Ocean Carbon & Biogeochemistry Program, 2016) Benway, Heather M. ; Alin, Simone R. ; Boyer, Elizabeth ; Cai, Wei-Jun ; Coble, Paula G. ; Cross, Jessica N. ; Friedrichs, Marjorie A. M. ; Goni, Miguel ; Griffith, Peter C. ; Herrmann, Maria ; Lohrenz, Steven E. ; Mathis, Jeremy T. ; McKinley, Galen A. ; Najjar, Raymond G. ; Pilskaln, Cynthia H. ; Siedlecki, Samantha A. ; Smith, Richard A.

Relative to their surface area, continental margins represent some of the largest carbon fluxes in the global ocean, but sparse and sporadic sampling in space and time makes these systems difficult to characterize and quantify. Recognizing the importance of continental margins to the overall North American carbon budget, terrestrial and marine carbon cycle scientists have been collaborating on a series of synthesis, carbon budgeting, and modeling exercises for coastal regions of North America, which include the Gulf of Mexico, the Laurentian Great Lakes (LGL), and the coastal waters of the Atlantic, Pacific, and Arctic Oceans. The Coastal CARbon Synthesis (CCARS) workshops and research activities have been conducted over the past several years as a partner activity between the Ocean Carbon and Biogeochemistry (OCB) Program and the North American Carbon Program (NACP) to synthesize existing data and improve quantitative assessments of the North American carbon budget.
Time of Emergence of surface ocean carbon dioxide trends in the North American coastal margins in support of ocean acidification observing system design.

(Frontiers Media, 2019-03-08) Turk, Daniela ; Wang, Hongjie ; Hu, Xinping ; Gledhill, Dwight K. ; Wang, Zhaohui Aleck ; Jiang, Liqing ; Cai, Wei-Jun

Time of Emergence (ToE) is the time when a signal emerges from the noise of natural variability. Commonly used in climate science for the detection of anthropogenic forcing, this concept has recently been applied to geochemical variables, to assess the emerging times of anthropogenic ocean acidification (OA), mostly in the open ocean using global climate and Earth System Models. Yet studies of OA variables are scarce within costal margins, due to limited multidecadal time-series observations of carbon parameters. ToE provides important information for decision making regarding the strategic configuration of observing assets, to ensure they are optimally positioned either for signal detection and/or process elicitation and to identify the most suitable variables in discerning OA-related changes. Herein, we present a short overview of ToE estimates on an OA variable, CO2 fugacity f(CO2,sw), in the North American ocean margins, using coastal data from the Surface Ocean CO2 Atlas (SOCAT) V5. ToE suggests an average theoretical timeframe for an OA signal to emerge, of 23(±13) years, but with considerable spatial variability. Most coastal areas are experiencing additional secular and/or multi-decadal forcing(s) that modifies the OA signal, and such forcing may not be sufficiently resolved by current observations. We provide recommendations, which will help scientists and decision makers design and implement OA monitoring systems in the next decade, to address the objectives of OceanObs19 (http://www.oceanobs19.net) in support of the United Nations Decade of Ocean Science for Sustainable Development (2021–2030) (https://en.unesco.org/ocean-decade) and the Sustainable Development Goal (SDG) 14.3 (https://sustainabledevelopment.un.org/sdg14) target to “Minimize and address the impacts of OA.”
Carbon budget of tidal wetlands, estuaries, and shelf waters of eastern North America

(John Wiley & Sons, 2018-04-04) Najjar, Raymond G. ; Herrmann, Maria ; Alexander, Richard ; Boyer, Elizabeth W. ; Burdige, David J. ; Butman, David ; Cai, Wei-Jun ; Canuel, Elizabeth A. ; Chen, Robert F. ; Friedrichs, Marjorie A. M. ; Feagin, Russell A. ; Griffith, Peter C. ; Hinson, Audra L. ; Holmquist, James R. ; Hu, Xinping ; Kemp, William M. ; Kroeger, Kevin D. ; Mannino, Antonio ; McCallister, S. Leigh ; McGillis, Wade R. ; Mulholland, Margaret R. ; Pilskaln, Cynthia H. ; Salisbury, Joseph E. ; Signorini, Sergio R. ; St-Laurent, Pierre ; Tian, Hanqin ; Tzortziou, Maria ; Vlahos, Penny ; Wang, Zhaohui Aleck ; Zimmerman, Richard C.

Carbon cycling in the coastal zone affects global carbon budgets and is critical for understanding the urgent issues of hypoxia, acidification, and tidal wetland loss. However, there are no regional carbon budgets spanning the three main ecosystems in coastal waters: tidal wetlands, estuaries, and shelf waters. Here we construct such a budget for eastern North America using historical data, empirical models, remote sensing algorithms, and process‐based models. Considering the net fluxes of total carbon at the domain boundaries, 59 ± 12% (± 2 standard errors) of the carbon entering is from rivers and 41 ± 12% is from the atmosphere, while 80 ± 9% of the carbon leaving is exported to the open ocean and 20 ± 9% is buried. Net lateral carbon transfers between the three main ecosystem types are comparable to fluxes at the domain boundaries. Each ecosystem type contributes substantially to exchange with the atmosphere, with CO2 uptake split evenly between tidal wetlands and shelf waters, and estuarine CO2 outgassing offsetting half of the uptake. Similarly, burial is about equal in tidal wetlands and shelf waters, while estuaries play a smaller but still substantial role. The importance of tidal wetlands and estuaries in the overall budget is remarkable given that they, respectively, make up only 2.4 and 8.9% of the study domain area. This study shows that coastal carbon budgets should explicitly include tidal wetlands, estuaries, shelf waters, and the linkages between them; ignoring any of them may produce a biased picture of coastal carbon cycling.
Best practice data standards for discrete chemical oceanographic observations

(Frontiers Media, 2022-01-21) Jiang, Li-Qing ; Pierrot, Denis ; Wanninkhof, Rik ; Feely, Richard A. ; Tilbrook, Bronte ; Alin, Simone R. ; Barbero, Leticia ; Byrne, Robert H. ; Carter, Brendan ; Dickson, Andrew G. ; Gattuso, Jean-Pierre ; Greeley, Dana ; Hoppema, Mario ; Humphreys, Matthew P. ; Karstensen, Johannes ; Lange, Nico ; Lauvset, Siv K. ; Lewis, Ernie R. ; Olsen, Are ; Perez, Fiz F. ; Sabine, Christopher ; Sharp, Jonathan D. ; Tanhua, Toste ; Trull, Thomas W. ; Velo, Anton ; Allegra, Andrew J. ; Barker, Paul M. ; Burger, Eugene ; Cai, Wei-Jun ; Chen, Chen-Tung A. ; Cross, Jessica N. ; Garcia, Hernan E. ; Hernandez-Ayon, Jose Martin ; Hu, Xinping ; Kozyr, Alex ; Langdon, Chris ; Lee, Kitack ; Salisbury, Joseph E. ; Wang, Zhaohui Aleck ; Xue, Liang

Effective data management plays a key role in oceanographic research as cruise-based data, collected from different laboratories and expeditions, are commonly compiled to investigate regional to global oceanographic processes. Here we describe new and updated best practice data standards for discrete chemical oceanographic observations, specifically those dealing with column header abbreviations, quality control flags, missing value indicators, and standardized calculation of certain properties. These data standards have been developed with the goals of improving the current practices of the scientific community and promoting their international usage. These guidelines are intended to standardize data files for data sharing and submission into permanent archives. They will facilitate future quality control and synthesis efforts and lead to better data interpretation. In turn, this will promote research in ocean biogeochemistry, such as studies of carbon cycling and ocean acidification, on regional to global scales. These best practice standards are not mandatory. Agencies, institutes, universities, or research vessels can continue using different data standards if it is important for them to maintain historical consistency. However, it is hoped that they will be adopted as widely as possible to facilitate consistency and to achieve the goals stated above.
DIC, TA, pH, DO from nGOM cruises conducted aboard the R/V Pelican throughout 2017, 2018 and July 2019.

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-01-19) Cai, Wei-Jun ; Li, Qian

DIC, TA, pH, DO from nGOM cruises conducted in February 2017, April 2017, May 2017, July 2017, September 2017, October 2017, January 2018, April 2018, June 2018, August 2018 and July 2019 aboard the R/V Pelican. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/831523
DIC, TA, calculated pH and carbonate saturation state in the summer bottom water in North Gulf of Mexico from 2006 to 2017

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-09-14) Cai, Wei-Jun ; Rabalais, Nancy

DIC, TA, calculated pH and carbonate saturation state in the summer bottom water in North Gulf of Mexico from 2006 to 2017 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/818773

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