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Item A machine learning model for reconstructing skin-friction drag over ocean surface waves(Journal of Fluid Mechanics, 2024-03-25) Yousefi, Kianoosh; Hora, Gurpreet Singh; Yang, Hongshuo; Veron, Fabrice; Giometto, Marco G.In order to improve the predictive abilities of weather and climate models, it is essential to understand the behaviour of wind stress at the ocean surface. Wind stress is contingent on small-scale interfacial dynamics typically not directly resolved in numerical models. Although skin friction contributes considerably to the total stress up to moderate wind speeds, it is notoriously challenging to measure and predict using physics-based approaches. This work proposes a supervised machine learning (ML) model that estimates the spatial distribution of the skin-friction drag over wind waves using solely wave elevation and wave age, which are relatively easy to acquire. The input–output pairs are high-resolution wave profiles and their corresponding surface viscous stresses collected from laboratory experiments. The ML model is built upon a convolutional neural network architecture that incorporates the Mish nonlinearity as its activation function. Results show that the model can accurately predict the overall distribution of viscous stresses; it captures the peak of viscous stress at/near the crest and its dramatic drop to almost null just past the crest in cases of intermittent airflow separation. The predicted area-aggregate skin friction is also in excellent agreement with the corresponding measurements. The proposed method offers a practical pathway for estimating both local and area-aggregate skin friction and can be easily integrated into existing numerical models for the study of air–sea interactions.Item A multi-decade record of high-quality fCO(2) data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)(Copernicus Gesellschaft MBH, 9/15/16) Bakker,Dorothee C. E.; Pfeil,Benjamin; Landa,Camilla S.; Metzl,Nicolas; O'Brien,Kevin M.; Olsen,Are; Smith,Karl; Cosca,Cathy; Harasawa,Sumiko; Jones,Stephen D.; Nakaoka,Shin-ichiro; Nojiri,Yukihiro; Schuster,Ute; Steinhoff,Tobias; Sweeney,Colm; Takahashi,Taro; Tilbrook,Bronte; Wada,Chisato; Wanninkhof,Rik; Alin,Simone R.; Balestrini,Carlos F.; Barbero,Leticia; Bates,Nicholas R.; Bianchi,Alejandro A.; Bonou,Frederic; Boutin,Jacqueline; Bozec,Yann; Burger,Eugene F.; Cai,Wei-Jun; Castle,Robert D.; Chen,Liqi; Chierici,Melissa; Currie,Kim; Evans,Wiley; Featherstone,Charles; Feely,Richard A.; Fransson,Agneta; Goyet,Catherine; Greenwood,Naomi; Gregor,Luke; Hankin,Steven; Hardman-Mountford,Nick J.; Harlay,Jerome; Hauck,Judith; Hoppema,Mario; Humphreys,Matthew P.; Hunt,ChristopherW; Huss,Betty; Ibanhez,J. Severino P.; Johannessen,Truls; Keeling,Ralph; Kitidis,Vassilis; Koertzinger,Arne; Kozyr,Alex; Krasakopoulou,Evangelia; Kuwata,Akira; Landschuetzer,Peter; Lauvset,Siv K.; Lefevre,Nathalie; Lo Monaco,Claire; Manke,Ansley; Mathis,Jeremy T.; Merlivat,Liliane; Millero,Frank J.; Monteiro,Pedro M. S.; Munro,David R.; Murata,Akihiko; Newberger,Timothy; Omar,Abdirahman M.; Ono,Tsuneo; Paterson,Kristina; Pearce,David; Pierrot,Denis; Robbins,Lisa L.; Saito,Shu; Salisbury,Joe; Schlitzer,Reiner; Schneider,Bernd; Schweitzer,Roland; Sieger,Rainer; Skjelvan,Ingunn; Sullivan,Kevin F.; Sutherland,Stewart C.; Sutton,Adrienne J.; Tadokoro,Kazuaki; Telszewski,Maciej; Tuma,Matthias; van Heuven,Steven M. A. C.; Vandemark,Doug; Ward,Brian; Watson,Andrew J.; Xu,Suqing; Dorothee C. E. Bakker, Benjamin Pfeil, Camilla S. Landa, Nicolas Metzl, Kevin M. OBrien,Are Olsen, Karl Smith, Cathy Cosca, Sumiko Harasawa, Stephen D. Jones,Shin-ichiro Nakaoka, Yukihiro Nojiri, Ute Schuster, Tobias Steinhoff, Colm Sweeney, Taro Takahashi, Bronte Tilbrook, Chisato Wada, Rik Wanninkhof, Simone R. Alin,Carlos F. Balestrini, Leticia Barbero, Nicholas R. Bates, Alejandro A. Bianchi,Fr_d_ric Bonou, Jacqueline Boutin, Yann Bozec21, Eugene F. Burger5, Wei-Jun Cai,Robert D. Castle, Liqi Chen, Melissa Chierici, Kim Currie, Wiley Evans, Charles Featherstone, Richard A. Feely, Agneta Fransson, Catherine Goyet,Naomi Greenwood, Luke Gregor, Steven Hankin, Nick J. Hardman-Mountford, J_rome Harlay, Judith Hauck, Mario Hoppema, Matthew P. Humphreys,ChristopherW. Hunt, Betty Huss, J. Severino P. Ibanhez, Truls Johannessen, Ralph Keeling, Vassilis Kitidis, Arne K_rtzinger, Alex Kozyr, Evangelia Krasakopoulou,Akira Kuwata, Peter Landschuetzer, Siv K. Lauvset, Nathalie Lefevre, Claire Lo Monaco,Ansley Manke, Jeremy T. Mathis, Liliane Merlivat, Frank J. Millero, Pedro M. S. Monteiro,David R. Munro, Akihiko Murata, Timothy Newberger, Abdirahman M. Omar,Tsuneo Ono, Kristina Paterson, David Pearce, Denis Pierrot, Lisa L. Robbins, Shu Saito, Joe Salisbury, Reiner Schlitzer, Bernd Schneider, Roland Schweitzer, Rainer Sieger,Ingunn Skjelvan, Kevin F. Sullivan, Stewart C. Sutherland, Adrienne J. Sutton,Kazuaki Tadokoro, Maciej Telszewski, Matthias Tuma, Steven M. A. C. van Heuven,Doug Vandemark, Brian Ward, Andrew J. Watson, and Suqing Xu; Cai, Wei-JunThe Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO(2) (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO(2) values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO(2) values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO(2) values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO(2) has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) "living data" publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014).Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi: 10.3334/CDIAC/OTG.SOCAT_V3_GRID.Item A recreation demand model for warmwater fishing in Delaware with welfare effects for improvements in catch rates, species diversity, and water clarity(Agricultural and Resource Economics Review, 2024-03-18) Dalvand, Kaveh; Parsons, GeorgeWe estimate a recreation demand model for warmwater fishing in Delaware and then use it to measure welfare gains associated with improved fishing quality as measured by catch rate of fish, diversity of species, and clarity of water. We use a “linked” site choice – trip frequency model with data gathered by the Delaware Division of Fish and Wildlife. Our site choice model includes 118 rivers and lakes in the state with detailed characteristics of each. We develop hypothetical scenarios of fishing quality improvement involving combinations of fish catch, fish diversity, and water clarity and apply it to individual water bodies, water basins, selected water body groupings, and statewide. Values are reported in seasonal per angler and aggregate terms.Item A roadmap for Ocean Negative Carbon Emission eco-engineering in sea-farming fields(The Innovation Geoscience, 2023-09-14) Jiao, Nianzhi; Zhu, Chenba; Liu, Jihua; Luo, Tingwei; Bai, Mindong; Yu, Zhiming; Chen, Quanrui; Rinkevich, Buki; Weinbauer, Markus; Thomas, Helmuth; Fernández-Méndez, Mar; López-Abbate, Celeste; Signori, Camila Negrão; Nagappa, Ramaiah; Koblížek, Michal; Kaartokallio, Hermanni; Hyun, Jung-Ho; Jiao, Fanglue; Chen, Feng; Cai, Wei-JunCarbon neutralization has become a significant, inevitable, and urgent strategy for both adaptation and mitigation of global warming caused by anthropogenic CO2 emissions, and its environmental consequences such as ocean acidification. However, the reduction of anthropogenic CO2 emissions often conflicts with economic development. In contrast, environmentally-friendly negative carbon emissions can be a way of killing two birds with one stone, capturing carbon dioxide and ensuring economic development, and therefore become imperative to achieve carbon-neutral goals.Item A satellite-based mobile warning system to reduce interactions with an endangered species(Ecological Applications, 2021-05-30) Breece, Matthew W.; Oliver, Matthew J.; Fox, Dewayne A.; Hale, Edward A.; Haulsee, Danielle E.; Shatley, Matthew; Bograd, Steven J.; Hazen, Elliott L.; Welch, HeatherEarth-observing satellites are a major research tool for spatially explicit ecosystem nowcasting and forecasting. However, there are practical challenges when integrating satellite data into usable real-time products for stakeholders. The need of forecast immediacy and accuracy means that forecast systems must account for missing data and data latency while delivering a timely, accurate, and actionable product to stakeholders. This is especially true for species that have legal protection. Acipenser oxyrinchus oxyrinchus (Atlantic sturgeon) were listed under the United States Endangered Species Act in 2012, which triggered immediate management action to foster population recovery and increase conservation measures. Building upon an existing research occurrence model, we developed an Atlantic sturgeon forecast system in the Delaware Bay, USA. To overcome missing satellite data due to clouds and produce a 3-d forecast of ocean conditions, we implemented data interpolating empirical orthogonal functions (DINEOF) on daily observed satellite data. We applied the Atlantic sturgeon research model to the DINEOF output and found that it correctly predicted Atlantic sturgeon telemetry occurrences over 90% of the time within a 3-d forecast. A similar framework has been utilized to forecast harmful algal blooms, but to our knowledge, this is the first time a species distribution model has been applied to DINEOF gap-filled data to produce a forecast product for fishes. To implement this product into an applied management setting, we worked with state and federal organizations to develop real-time and forecasted risk maps in the Delaware River Estuary for both state-level managers and commercial fishers. An automated system creates and distributes these risk maps to subscribers’ mobile devices, highlighting areas that should be avoided to reduce interactions. Additionally, an interactive web interface allows users to plot historic, current, future, and climatological risk maps as well as the underlying model output of Atlantic sturgeon occurrence. The mobile system and web tool provide both stakeholders and managers real-time access to estimated occurrences of Atlantic sturgeon, enabling conservation planning and informing fisher behavior to reduce interactions with this endangered species while minimizing impacts to fisheries and other projects.Item A subsurface eddy associated with a submarine canyon increases availability and delivery of simulated Antarctic krill to penguin foraging regions(Marine Ecology Progress Series, 2022-12-08) Hudson, K.; Oliver, M. J.; Kohut, J.; Dinniman, M. S.; Klinck, J. M.; Cimino, M. A.; Bernard, K. S.; Statscewich, H.; Fraser, W.The distribution of marine zooplankton depends on both ocean currents and swimming behavior. Many zooplankton perform diel vertical migration (DVM) between the surface and subsurface, which can have different current regimes. If concentration mechanisms, such as fronts or eddies, are present in the subsurface, they may impact zooplankton near-surface distributions when they migrate to near-surface waters. A subsurface, retentive eddy within Palmer Deep Canyon (PDC), a submarine canyon along the West Antarctic Peninsula (WAP), retains diurnal vertically migrating zooplankton in previous model simulations. Here, we tested the hypothesis that the presence of the PDC and its associated subsurface eddy increases the availability and delivery of simulated Antarctic krill to nearby penguin foraging regions with model simulations over a single austral summer. We found that the availability and delivery rates of simulated krill to penguin foraging areas adjacent to PDC were greater when the PDC was present compared to when PDC was absent, and when DVM was deepest. These results suggest that the eddy has potential to enhance krill availability to upper trophic level predators and suggests that retention may play a significant role in resource availability for predators in other similar systems along the WAP and in other systems with sustained subsurface eddies.Item Agents of change and temporal nutrient dynamics in the Altamaha River Watershed(Ecological Society of America, 2017-01-23) Takagi, Kimberly K.; Hunter, Kimberley S.; Cai, Wei-Jun; Joye, Samantha B.; Kimberly K. Takagi, Kimberley S. Hunter, Wei-Jun Cai, and Samantha B. Joye; Cai, Wei-JunNutrient and carbon dynamics in river ecosystems are shifting, and climate change is likely a driving factor; however, some previous studies indicate anthropogenic modification of natural resources may supersede the effects of climate. To understand temporal changes in river ecosystems, consideration of how these agents act independently and collectively to affect watershed biogeochemistry is necessary. Through the Georgia Coastal Ecosystems Long-Term Ecological Research Project, we assessed nutrient (phosphorus, nitrogen, silicate) and carbon dynamics, with specific regard to import and export, in the Altamaha River Basin from 2000 to 2012. This is the first study in the region to document the biogeochemical patterns in the Altamaha’s four main tributaries, the Little Ocmulgee, Ocmulgee, Oconee, and Ohoopee rivers, and the relationships between biogeochemistry and historical precipitation and discharge patterns as well as agricultural and population census data. As discharge patterns are a primary driver of nutrient loads, we determined that water use was a dominant factor in the shifting ecosystem dynamics. Dissolved inorganic nitrogen loads were primarily driven by population density and dissolved inorganic phosphorus loads were strongly influenced by livestock biomass. Taken together, we conclude that both the transportation and biogeochemical cycling of nutrients within the Altamaha River Watershed were highly impacted by anthropogenic influences, which were then further exacerbated by continued climate change. Furthermore, the N-and P-loads in the Altamaha River and tributaries were dominated by dissolved organic nitrogen and dissolved organic phosphorus, emphasizing a need to further study the bioavailability of these species and the mechanisms driving their potential ecological impacts.Item Aggregation and Degradation of Dispersants and Oil by Microbial Exopolymers (ADDOMEx): Toward a Synthesis of Processes and Pathways of Marine Oil Snow Formation in Determining the Fate of Hydrocarbons(Frontiers in Marine Science, 2021-07-19) Quigg, Antonietta; Santschi, Peter H.; Xu, Chen; Ziervogel, Kai; Kamalanathan, Manoj; Chin, Wei-Chun; Burd, Adrian B.; Wozniak, Andrew; Hatcher, Patrick G.Microbes (bacteria, phytoplankton) in the ocean are responsible for the copious production of exopolymeric substances (EPS) that include transparent exopolymeric particles. These materials act as a matrix to form marine snow. After the Deepwater Horizon oil spill, marine oil snow (MOS) formed in massive quantities and influenced the fate and transport of oil in the ocean. The processes and pathways of MOS formation require further elucidation to be better understood, in particular we need to better understand how dispersants affect aggregation and degradation of oil. Toward that end, recent work has characterized EPS as a function of microbial community and environmental conditions. We present a conceptual model that incorporates recent findings in our understanding of the driving forces of MOS sedimentation and flocculent accumulation (MOSSFA) including factors that influence the scavenging of oil into MOS and the routes that promote decomposition of the oil post MOS formation. In particular, the model incorporates advances in our understanding of processes that control interactions between oil, dispersant, and EPS in producing either MOS that can sink or dispersed gels promoting microbial degradation of oil compounds. A critical element is the role of protein to carbohydrate ratios (P/C ratios) of EPS in the aggregation process of colloid and particle formation. The P/C ratio of EPS provides a chemical basis for the “stickiness” factor that is used in analytical or numerical simulations of the aggregation process. This factor also provides a relative measure for the strength of attachment of EPS to particle surfaces. Results from recent laboratory experiments demonstrate (i) the rapid formation of microbial assemblages, including their EPS, on oil droplets that is enhanced in the presence of Corexit-dispersed oil, and (ii) the subsequent rapid oil oxidation and microbial degradation in water. These findings, combined with the conceptual model, further improve our understanding of the fate of the sinking MOS (e.g., subsequent sedimentation and preservation/degradation) and expand our ability to predict the behavior and transport of spilled oil in the ocean, and the potential effects of Corexit application, specifically with respect to MOS processes (i.e., formation, fate, and half-lives) and Marine Oil Snow Sedimentation and Flocculent Accumulation.Item Along-Wind Dispersion by Horizontal Turbulent Jets in the Upper Ocean(Journal of Physical Oceanography, 2021-10-01) Kukulka, Tobias; Thoman, Todd X.Dispersion processes in the ocean surface boundary layer (OSBL) determine marine material distributions such as those of plankton and pollutants. Sheared velocities drive shear dispersion, which is traditionally assumed to be due to mean horizontal currents that decrease from the surface. However, OSBL turbulence supports along-wind jets; located in near-surface convergence and downwelling regions, such turbulent jets contain strong local shear. Through wind-driven idealized and large-eddy simulation (LES) models of the OSBL, this study examines the role of turbulent along-wind jets in dispersing material. In the idealized model, turbulent jets are generated by prescribed cellular flow with surface convergence and associated downwelling regions. Numeric and analytic model solutions reveal that horizontal jets substantially contribute to along-wind dispersion for sufficiently strong cellular flows and exceed contributions due to vertical mean shear for buoyant surface-trapped material. However, surface convergence regions also accumulate surface-trapped material, reducing shear dispersion by jets. Turbulence resolving LES results of a coastal depth-limited ocean agree qualitatively with the idealized model and reveal long-lived coherent jet structures that are necessary for effective jet dispersion. These coastal results indicate substantial jet contributions to along-wind dispersion. However, jet dispersion is likely less effective in the open ocean because jets are shorter lived, less organized, and distorted due to spiraling Ekman currents.Item And on top of all that…: Coping with ocean acidification in the midst of many stressors(The Oceanography Society., 2015-06-01) Breitburg, Denise L.; Salisbury, Joseph; Bernhard, Joan M.; Cai, Wei-Jun; Dupont, Sam; Doney, Scott C.; Kroeker, Kristy J.; Levin, Lisa A.; Long, Christopher; Milke, Lisa M.; Miller, Seth H.; Phelan, Beth; Passow, Uta; Seibel, Brad A.; Todgham, Anne E.; Tarrant, Ann M.; Denise L. Breitburg, Joseph Salisbury, Joan M. Bernhard, Wei-Jun Cai, Sam Dupont, Scott C. Doney, Kristy J. Kroeker, Lisa A. Levin, W. Christopher Long, Lisa M. Milke, Seth H. Miller, Beth Phelan, Uta Passow, Brad A. Seibel, Anne E. Todgham, and Ann M. Tarrant; Cai, Wei-JunOceanic 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.Item Assessing the use of a camera system within an autonomous underwater vehicle for monitoring the distribution and density of sea scallops (Placopecten magellanicus) in the Mid-Atlantic Bight(National Marine Fisheries Service., 2016-04-26) Walker, Justin H.; Trembanis, Arthur C.; Miller, Douglas C.; Justin H. Walker, Arthur C. Trembanis and Douglas C. Miller; Walker, Justin H.; Trembanis, Arthur C.; Miller, Douglas C.The sea scallop (Placopecten magellanicus) fishery in the Atlantic is assessed during annual surveys by using both dredging and surface-deployed imaging techniques. In this pilot study in the Mid-Atlantic Bight, we used an autonomous underwater vehicle (AUV) to photograph the seafloor and to evaluate its use for determining scallop density and size. During 22 surveys in 2011, 257 km of seafloor were photographed, resulting in over 203,000 color images. Using trained annotators and photogrammetric software, we determined scallop density and shell heights for 15,252 scallops. The inshore scallop grounds near Long Island (at depths <40 m) had a density of 0.077 scallops per m2, whereas the inshore grounds of the New York Bight had a density of 0.012 scallops per m2. Shell heights derived from images were found to agree well with measurements from scallops collected with a commercial dredge. We show that images obtained with an AUV can be used to reliably estimate both density and shell height consistent with direct sampling from the same area. Moreover, side-scan sonar images obtained with an AUV can be used to detect dredge scars and, therefore, can provide a simultaneous, relative estimate of fishing effort in that area. AUVs provide a highly accurate suite of data for each survey site and therefore allow the design of experimental studies of fishing practices.Item Bioluminescence as an ecological factor during high Arctic polar night(Nature Publishing Group, 11/2/16) Cronin,Heather A.; Cohen,Jonathan H.; Berge,Jorgen; Johnsen,Geir; Moline,Mark A.; Heather A. Cronin, Jonathan H. Cohen, J�rgen Berge, Geir Johnsen, Mark A. Moline; Cohen, Jonathan Hirsch; Moline, Mark AlanBioluminescence commonly influences pelagic trophic interactions at mesopelagic depths. Here we characterize a vertical gradient in structure of a generally low species diversity bioluminescent community at shallower epipelagic depths during the polar night period in a high Arctic fjord with in situ bathyphotometric sampling. Bioluminescence potential of the community increased with depth to a peak at 80 m. Community composition changed over this range, with an ecotone at 20-40 m where a dinoflagellate-dominated community transitioned to dominance by the copepod Metridia longa. Coincident at this depth was bioluminescence exceeding atmospheric light in the ambient pelagic photon budget, which we term the bioluminescence compensation depth. Collectively, we show a winter bioluminescent community in the high Arctic with vertical structure linked to attenuation of atmospheric light, which has the potential to influence pelagic ecology during the light-limited polar night.Item Carbonate Parameter Estimation and Its Application in Revealing Temporal and Spatial Variation in the South and Mid-Atlantic Bight, USA(Journal of Geophysical Research: Oceans, 2022-06-22) Li, Xinyu; Xu, Yuan-Yuan; Kirchman, David L.; Cai, Wei-JunTo overcome the limitations due to sporadic carbonate parameter data, this study developed and evaluated empirical multiple linear regression (MLR) models for dissolved inorganic carbon (DIC), pH in total scale (pHT), and aragonite carbonate saturation state (ΩAr) using hydrographic data (temperature, salinity, and oxygen) measured during 2007–2018 in the South Atlantic Bight (SAB) and Mid-Atlantic Bight (MAB) along the U.S. East Coast. We first reviewed the assumptions and routines of MLR models and then generated MLR models for each cruise for all three carbonate parameters in each region and assessed model performance. Models derived from measured spectrophotometric pH have smaller uncertainties than pHT models based on pH calculated from total alkalinity (TA) and DIC. The regional differences of carbonate parameters between MAB and SAB are reflected in the coefficients of the empirical models. The MLR model temporal consistency indicates that the effect of the atmospheric CO2 increase on seawater carbonate parameters cannot be unequivocally resolved for the period of this study in the regions. Therefore, we combined different cruises to build composite models for each region. The composite models can capture the key features in the SAB and MAB. To further assess the model applicability, we applied our models to Biogeochemical-Argo data to reconstruct carbonate parameters. The algorithm in this study helps to reconstruct seawater carbonate chemistry using proxy data of high spatial and temporal resolution, which will enhance our understanding of physical and biological processes on carbon cycle and the long-term anthropogenic carbon inputs in coastal oceans. Key Points: - pH estimation models based on measured pH have smaller uncertainties than those based on pH calculated from other carbonate parameters - Models differ between the Mid and South Atlantic Bights, and their temporal changes due to atmospheric CO2 are limited over 10 years - Multiple linear regression models provide a promising tool for reconstructing carbonate parameters using data from autonomous platforms Plain Language Summary: Coastal ocean carbon cycling is a complex process that is influenced by various physical and biological processes. Sporadic carbonate data challenges our understanding of carbon cycling in coastal areas. We first reviewed the assumptions and routines in developing coastal empirical models, and then built linear regression models with frequently measured seawater properties, such as temperature, salinity, and O2, to estimate the carbonate variables along the U.S. East Coast. The key features of seawater carbonate parameters are captured by the empirical models. The sub-regional differences are reflected in the coefficients of the empirical models. We also found that the effect of anthropogenic carbon dioxide increase on the DIC is limited over 10 years. This study helps to reconstruct seawater carbonate chemistry where data are limited, predict future changes in coastal carbonate chemistry, and enhance our understanding of long-term anthropogenic carbon inputs in the coastal ocean.Item The changing CO2 sink in the western Arctic Ocean from 1994 to 2019(Global Biogeochemical Cycles, 2021-12-28) Ouyang, Zhangxian; Li, Yun; Zhong, Wenli; Murata, Akihiko; Nishino, Shigeto; Wu, Yingxu; Jin, Meibing; Kirchman, David; Chen, Liqi; Cai, Wei-JunThe Arctic Ocean has turned from a perennial ice-covered ocean into a seasonally ice-free ocean in recent decades. Such a shift in the air-ice-sea interface has resulted in substantial changes in the Arctic carbon cycle and related biogeochemical processes. To quantitatively evaluate how the oceanic CO2 sink responds to rapid sea ice loss and to provide a mechanistic explanation, here we examined the air-sea CO2 flux and the regional CO2 sink in the western Arctic Ocean from 1994 to 2019 by two complementary approaches: observation-based estimation and a data-driven box model evaluation. The pCO2 observations and model results showed that summer CO2 uptake significantly increased by about 1.4 ± 0.6 Tg C decade−1 in the Chukchi Sea, primarily due to a longer ice-free period, a larger open area, and an increased primary production. However, no statistically significant increase in CO2 sink was found in the Canada Basin and the Beaufort Sea based on both observations and modeled results. The reduced sea ice coverage in summer in the Canada Basin and the enhanced wind speed in the Beaufort Sea potentially promoted CO2 uptake, which was, however, counteracted by a rapidly decreased air-sea pCO2 gradient therein. Therefore, the current and future Arctic Ocean CO2 uptake trends cannot be sufficiently reflected by the air-sea pCO2 gradient alone because of the sea ice variations and other environmental factors.Item Coastal phytoplankton blooms expand and intensify in the 21st century(Nature, 2023-03-01) Dai, Yanhui; Yang, Shangbo; Zhao, Dan; Hu, Chuanmin; Xu, Wang; Anderson, Donald M.; Li, Yun; Song, Xiao-Peng; Boyce, Daniel G.; Gibson, Luke; Zheng, Chunmiao; Feng, LianPhytoplankton blooms in coastal oceans can be beneficial to coastal fisheries production and ecosystem function, but can also cause major environmental problems1,2—yet detailed characterizations of bloom incidence and distribution are not available worldwide. Here we map daily marine coastal algal blooms between 2003 and 2020 using global satellite observations at 1-km spatial resolution. We found that algal blooms occurred in 126 out of the 153 coastal countries examined. Globally, the spatial extent (+13.2%) and frequency (+59.2%) of blooms increased significantly (P < 0.05) over the study period, whereas blooms weakened in tropical and subtropical areas of the Northern Hemisphere. We documented the relationship between the bloom trends and ocean circulation, and identified the stimulatory effects of recent increases in sea surface temperature. Our compilation of daily mapped coastal phytoplankton blooms provides the basis for global assessments of bloom risks and benefits, and for the formulation or evaluation of management or policy actions.Item Comparison of Extreme Coastal Flooding Events between Tropical and Midlatitude Weather Systems in the Delaware and Chesapeake Bays for 1980–2019(Journal of Applied Meteorology and Climatology, 2022-04-26) Callahan, John A.; Leathers, Daniel J.; Callahan, Christina L.Coastal flooding is one of the most costly and deadly natural hazards facing the U.S. mid-Atlantic region today. Impacts in this heavily populated and economically significant region are caused by a combination of the location’s exposure and natural forcing from storms and sea level rise. Tropical cyclones (TCs) and midlatitude (ML) weather systems each have caused extreme coastal flooding in the region. Skew surge was computed over each tidal cycle for the past 40 years (1980–2019) at several tide gauges in the Delaware and Chesapeake Bays to compare the meteorological component of surge for each weather type. Although TCs cause higher mean surges, ML weather systems can produce surges just as severe and occur much more frequently, peaking in the cold season (November–March). Of the top 10 largest surge events, TCs account for 30%–45% in the Delaware and upper Chesapeake Bays and 40%–45% in the lower Chesapeake Bay. This percentage drops to 10%–15% for larger numbers of events in all regions. Mean sea level pressure and 500-hPa geopotential height (GPH) fields of the top 10 surge events from ML weather systems show a low pressure center west-southwest of “Delmarva” and a semistationary high pressure center to the northeast prior to maximum surge, producing strong easterly winds. Low pressure centers intensify under upper-level divergence as they travel eastward, and the high pressure centers are near the GPH ridges. During lower-bay events, the low pressure centers develop farther south, intensifying over warmer coastal waters, with a south-shifted GPH pattern relative to upper-bay events. Significance Statement Severe coastal flooding is a year-round threat in the U.S. mid-Atlantic region, and impacts are projected to increase in magnitude and frequency. Research into the meteorological contribution to storm surge, separate from mean sea level and tidal phase, will increase the scientific understanding and monitoring of changing atmospheric conditions. Tropical cyclones and midlatitude weather systems both significantly impact the mid-Atlantic region during different times of year. However, climate change may alter the future behavior of these systems differently. Understanding the synoptic environment and quantifying the surge response and subbay geographic variability of each weather system in this region will aid in public awareness, near-term emergency preparation, and long-term planning for coastal storms.Item Coral-bleaching responses to climate change across biological scales(Global Change Biology, 2022-06-14) van Woesik, Robert; Shlesinger, Tom; Grottoli, Andréa G.; Toonen, Rob J.; Vega Thurber, Rebecca; Warner, Mark E.; Hulver, Ann Marie; Chapron, Leila; McLachlan, Rowan H.; Albright, Rebecca; Crandall, Eric; DeCarlo, Thomas M.; Donovan, Mary K.; Eirin-Lopez, Jose; Harrison, Hugo B.; Heron, Scott F.; Huang, Danwei; Humanes, Adriana; Krueger, Thomas; Madin, Joshua S.; Manzello, Derek; McManus, Lisa C.; Matz, Mikhail; Muller, Erinn M.; Rodriguez-Lanetty, Mauricio; Vega-Rodriguez, Maria; Voolstra, Christian R.; Zaneveld, JesseThe global impacts of climate change are evident in every marine ecosystem. On coral reefs, mass coral bleaching and mortality have emerged as ubiquitous responses to ocean warming, yet one of the greatest challenges of this epiphenomenon is linking information across scientific disciplines and spatial and temporal scales. Here we review some of the seminal and recent coral-bleaching discoveries from an ecological, physiological, and molecular perspective. We also evaluate which data and processes can improve predictive models and provide a conceptual framework that integrates measurements across biological scales. Taking an integrative approach across biological and spatial scales, using for example hierarchical models to estimate major coral-reef processes, will not only rapidly advance coral-reef science but will also provide necessary information to guide decision-making and conservation efforts. To conserve reefs, we encourage implementing mesoscale sanctuaries (thousands of km2) that transcend national boundaries. Such networks of protected reefs will provide reef connectivity, through larval dispersal that transverse thermal environments, and genotypic repositories that may become essential units of selection for environmentally diverse locations. Together, multinational networks may be the best chance corals have to persist through climate change, while humanity struggles to reduce emissions of greenhouse gases to net zero.Item Correcting a major error in assessing organic carbon pollution in natural waters(Science Advances, 2021-04-14) Jiao, Nianzhi; Liu, Jihua; Edwards, Bethanie; Lv, Zongqing; Cai, Ruanhong; Liu,Yongqin; Xiao, Xilin; Wang, Jianning; Jiao, Fanglue; Wang, Rui; Huang, Xingyu; Guo, Bixi; Sun, Jia; Zhang, Rui; Zhang, Yao; Tang, Kai; Zheng, Qiang; Azam, Farooq; Batt, John; Cai, Wei-Jun; He, Chen; Herndl, Gerhard J.; Hill, Paul; Hutchins, David; LaRoche, Julie; Lewis, Marlon; MacIntyre, Hugh; Polimene, Luca; Robinson, Carol; Shi, Quan; Suttle, Curtis A.; Thomas, Helmuth; Wallace, Douglas; Legendre, LouisMicrobial degradation of dissolved organic carbon (DOC) in aquatic environments can cause oxygen depletion, water acidification, and CO2 emissions. These problems are caused by labile DOC (LDOC) and not refractory DOC (RDOC) that resists degradation and is thus a carbon sink. For nearly a century, chemical oxygen demand (COD) has been widely used for assessment of organic pollution in aquatic systems. Here, we show through a multicountry survey and experimental studies that COD is not an appropriate proxy of microbial degradability of organic matter because it oxidizes both LDOC and RDOC, and the latter contributes up to 90% of DOC in high-latitude forested areas. Hence, COD measurements do not provide appropriate scientific information on organic pollution in natural waters and can mislead environmental policies. We propose the replacement of the COD method with an optode-based biological oxygen demand method to accurately and efficiently assess organic pollution in natural aquatic environments.Item Counterfactual Modeling of Multispecies Fisheries Outcomes under Market-Based Regulation(Journal of the Association of Environmental and Resource Economists, 2024-04-04) Birkenbach, Anna M.; Lee, Min-Yang; Smith, Martin D.Much of the recent work evaluating economic impacts of rights-based management (“catch shares”) in fisheries relies on treatment effects models, which typically identify net effects of the policy change but not underlying causal mechanisms. We develop a structural discrete choice model of individual vessel behavior to elucidate how catch shares—and the policies that they replace—influence species targets, timing of fishing activity, and the value generated from the resource. We estimate our model using trip-level data on 286 New England groundfish vessels before and after catch-share implementation. Controlling for weather, costs, and prices, we recover structural parameters characterizing microlevel targeting decisions and simulate the effects of removing input controls and replacing them with catch shares. We find that, under catch shares, the fleet experienced longer and more even fishing seasons, somewhat higher groundfish revenues, fewer closures, and a more balanced portfolio of target stocks than in the counterfactual. Dataverse data: https://doi.org/10.7910/DVN/PJ4YZZItem CTD and UBAT data from: Comparisons of underwater light from atmospheric and mechanically stimulated bioluminescence sources in high Arctic Polar Night(2024-01-22) Shulman, Igor; Cohen, Jonathan H.; Anderson, Stephanie; Penta, Bradley; Moline, Mark A.For each station, we profiled an instrumented cage from the surface to 120 m (bottom depth ≈ 200 m). The cage was equipped with a bathyphotometer (UBAT–Underwater Bioluminescence Assessment Tool, WetLabs, Philomath, OR) and CTD (SBE 49 FastCAT, Sea-Bird, Bellevue, WA). For each cast, we held instruments for 4 min at every 20 m depth interval to measure bioluminescence. Fjord sampling in January 2014 (A2014, B2014, C2014, D2014) was conducted in Kongsfjord, Svalbard (78° 56.16'N, 11° 56.58'E). For more detail on this data collection see: Cronin et al. (2016) Scientific Reports 6:36374, DOI: 10.1038/srep36374 Fjord sampling in January 2017 (A2017) was conducted in Rijpfjorden, Svalbard (80° 18.261'N / 02° 215.705'E). For more detail on this data collection see: Shulman et al. (2020) Ocean Dynamics 70:1211–1223, https://doi.org/10.1007/s10236-020-01392-2 Shelf/slope sampling in January 2017 (B2017, C2017) was conducted offshore from Rijpfjorden, Svalbard (80° 55.364'N / 017°32.469E, 80°35.923'N / 013°40.636'E). For more detail on this data collection see: Shulman et al. (2020) Ocean Dynamics 70:1211–1223, https://doi.org/10.1007/s10236-020-01392-2 Arctic basin sampling in January 2017 (D2017) was conducted further offshore of Rijpfjorden, Svalbard (81°21.285'N / 014°51.079'E). For more detail on this data collection see: Shulman et al. (2020) Ocean Dynamics 70:1211–1223, https://doi.org/10.1007/s10236-020-01392-2 The separate tabs in this spreadsheet correspond to each sampling location described above. CTD and UBAT data are included, with bioluminescence data provided as both 1 second averages and at 60Hz resolution Parameters and units for the profile at each station from merged CTD and UBAT records are: Time (ms) Record number (NA) Temp (C) Depth (m) Salinity (psu) Calibration Coeff for HV step (photons/s) Avg BL (photons/s) Pump RPM (RPM) System Voltage (V) Flow RPM (RPM) HV step (V) 60Hzdata_n [60 Hz digitized raw A/D counts, n=1-60] (photons)