Progress in Oceanography最新文献

{"title":"Sources, Transport, and accumulation of Mercury in the northwestern Mediterranean margin sediments during the Industrial Era and influence of turbiditic events","authors":"Daniel Cossa ,&nbsp;Roselyne Buscail ,&nbsp;Bernard Dennielou ,&nbsp;Olivier Radakovitch ,&nbsp;Pere Puig ,&nbsp;Alexis Khripounoff ,&nbsp;Bernard Boutier ,&nbsp;Serge Berné","doi":"10.1016/j.pocean.2023.103186","DOIUrl":"10.1016/j.pocean.2023.103186","url":null,"abstract":"<div><p>Sources and pathways of the Hg accumulated in the sediments of the Gulf of Lion (GoL) and its adjacent marine areas (Northwestern Mediterranean) have been explored using sediment grab samples, sediment cores, and sediment trap samples. The main source of Hg along this margin is the Rhône River, whose suspended sediments settle mainly in the prodelta area but also along the mid-shelf, then reaching the continental rise <em>via</em> wave resuspension and cascading of dense shelf waters. Seaward, these riverine particles are mixed with carbonated ooze conveyed to the bottom by the biological pump. The Hg is enriched in surface sediments of the GoL with decreasing concentrations westward and seaward from the Rhône prodelta to the continental rise. Dated cores from the Rhône prodelta give access to riverine sediments deposited over the last 400 years and show that the Hg concentration time trend resembles the evolution of coal consumption in France, peaking during in the 1960s. Similar trends were observed in sediment cores collected along the GoL slope and submarine canyons along with the preservation of traces of erosion and sediment instability events. Seaward, on the continental rise, the Hg concentration distribution suggests the deposition of fine planktonic-derived material and particles episodically advected from the shelf during deep cascading pulses. Anthropogenic Hg accumulated in GoL and continental rise sediments during the Industrialized Era is ∼ 150 Mg (tons), two-thirds of which are buried in the Rhône prodelta area. Significant correlations are found between Hg and organic matter in GoL sediments, but the relationships differ between areas and are disrupted by the inputs of anthropogenic Hg and by the Hg availability in the Rhône River watershed during the pre-industrial period. The HgT availability in waters appears to be the limiting factor to the Hg enrichment of the particulate organic matter. Monomethyl mercury (MMHg), which represents on average 0.3 % of the total Hg, was positively correlated to total Hg. Their distributions suggest <em>in situ</em> MMHg formation and a more effective net Hg methylation for surface sediment or particles collected in traps compared with particles buried in the sedimentary column.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138469413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations of near-inertial internal wave amplification and enhanced mixing after surface reflection","authors":"Kun Liu ,&nbsp;Xu Chen ,&nbsp;Peng Zhan ,&nbsp;Lianglong Da ,&nbsp;Hui Wang ,&nbsp;Wuhong Guo ,&nbsp;Jingyi Liu ,&nbsp;Lei Chen ,&nbsp;Bing Liu ,&nbsp;Guandong Gao ,&nbsp;Deyan Tian","doi":"10.1016/j.pocean.2023.103177","DOIUrl":"10.1016/j.pocean.2023.103177","url":null,"abstract":"<div><p>The overreflection process of near-inertial internal waves (NIWs) has been theoretically predicted for several decades; however, to the best of our knowledge, this phenomenon has never been comprehensively investigated in real ocean scenarios. Based on the buoy observations collected several days after the passage of Typhoon Lekima in the Yellow Sea, a NIW surface overreflection event is clearly captured. The observed NIWs undergo nearly total reflection meridionally but are amplified zonally after reflection by approximately 20% in amplitude and 56% in vertically integrated horizontal kinetic energy. Ray tracing analysis indicates that the NIW was generated in the wake of Typhoon Lekima in the area north of the Shandong Peninsula and may propagated to the buoy station as coastal-trapped internal Kelvin waves. A simulation using a slab mixed layer model suggests that local wind work was insufficient to generate the amplified NIWs. The temporal evolution of near-inertial energy also implies that the intensified near-inertial waves cannot be attributed to the spontaneous generation resulting from unbalanced flows or the parametric subharmonic instability of M₂ internal tides during the reflection period. We found a high temporal correlation between the zonal NIW enhancement and the duration of a meridional lens-type shear flow after reflection, which is consistent with the Stern’s overreflection theory (<span>Stern, 1977</span>) that perpendicular background shear flow can feed energy to the incident NIWs. This indicates that the enhanced NIW may be stimulated by the near-surface reflection and the rotation effect plays a crucial role in the NIWs overreflection process in the real ocean. Furthermore, enhanced instability are found between the ocean surface and the upper thermocline after reflection. This study provides observational evidence that the background field could inject energy into the near-inertial band through NIW overreflection process, and may shed some light on understanding upper ocean mixing caused by NIW reflection.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138438531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of Atmospheric-Driven Surface Currents on The Gulf of Cadiz Continental Shelf and its link with The Strait of Gibraltar and The Western Alboran Sea","authors":"S. Sirviente ,&nbsp;M. Bolado-Penagos ,&nbsp;J.J. Gomiz-Pascual ,&nbsp;J. Romero-Cózar ,&nbsp;A. Vázquez ,&nbsp;M Bruno","doi":"10.1016/j.pocean.2023.103175","DOIUrl":"10.1016/j.pocean.2023.103175","url":null,"abstract":"<div><p>Several studies about the coastal circulation over the continental shelf of the Gulf of Cadiz have been published in the last twenty years. One of the most studied features in these papers are the so-called Coastal Counter Currents (CCCs) which are located roughly between the 100 m isobath and the coastline and are directed westwards. Despite the considerable number of articles devoted to the analysis of this phenomenon, the actual along-coast extension and origin of these CCCs currently remain unclear.</p><p>In the present study, different mechanisms are proposed to explain the development of these CCCs. They have been revised and discussed taking into account the latest findings from a recent analysis that utilized surface currents derived from High Frequency Radar (HFR) as well as numerical model simulations. The most interesting finding is that the most intense CCCs events are initiated on the coastal margin of the westernmost side of the Strait of Gibraltar, and they are extended further west of Cape Santa Maria. Furthermore, these intense and extensive CCCs seem to be triggered by the joint action of local winds over the Gulf of Cadiz and additional remote effects which are coming from (i) the wind forcing over the Alboran Sea and the easternmost side of the Strait of Gibraltar, and (ii) the Sea Level Atmospheric Pressure forcing over the Ligurian Sea (western Mediterranean Sea). In addition, the same forcing mechanisms are valid to explain the eastward intensification of the coastal currents.</p><p>The most relevant feature of the hydrodynamic pattern originated by this combination of forcing agents is its quasi-geostrophic adjustment against the coast in the whole spatial dominion. In addition, these results offer a clear example of how important the effects of forcing in rather remote regions may be in defining the hydrodynamic patterns of certain oceanographic regions.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138438530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spring phytoplankton bloom phenology during recent climate warming on the Bering Sea shelf","authors":"Jens M. Nielsen ,&nbsp;Michael F. Sigler ,&nbsp;Lisa B. Eisner ,&nbsp;Jordan T. Watson ,&nbsp;Lauren A. Rogers ,&nbsp;Shaun W. Bell ,&nbsp;Noel Pelland ,&nbsp;Calvin W. Mordy ,&nbsp;Wei Cheng ,&nbsp;Kirill Kivva ,&nbsp;Sage Osborne ,&nbsp;Phyllis Stabeno","doi":"10.1016/j.pocean.2023.103176","DOIUrl":"https://doi.org/10.1016/j.pocean.2023.103176","url":null,"abstract":"<div><p>High-latitude ecosystems commonly experience large phytoplankton blooms in spring, which provide basal resources for a range of grazers including zooplankton, benthic consumers and fishes. Variation of the timing and intensity of the spring phytoplankton bloom influences the degree of spatial and temporal overlap with consuming organisms. In the Bering Sea, blooms occur in association with ice retreat or as pelagic open-water blooms. In the last few years, the Bering Sea shelf experienced unprecedented and widespread warming. Understanding how those climatic changes subsequently influenced phytoplankton bloom dynamics is critical for evaluating Bering Sea food web responses. We estimate spring bloom timing and type (ice-associated, open-water) across the Bering Sea shelf using a combination of data from the long-running oceanographic moorings on the eastern shelf (M2, M4, M5, M8) and satellite ocean color data from 1998 to 2022. We assess 1) if the Bering Sea shelf experienced noticeable changes in spring bloom timing or type in the last two decades, 2) whether bloom phenology was accentuated by the recent warm period (2018–2019), and 3) what influences do winds and sea surface temperatures have on spring bloom timing and where are these variables influential? Our spatial analyses reinforce the conclusion that ice retreat is the dominant forcing factor of bloom timing for the Bering Sea shelf with some influence of wind for open-water blooms. Overall, bloom timing has not shifted seasonally with climate warming in the last two decades for most of the Bering Sea shelf, except for nearshore areas and mainly in the northern Bering Sea. In warm years when ice retreats early prior to the last week of March, blooms form in open waters and bloom timing on the middle and outer shelf is delayed when wind mixing is prevalent in ice-free springs. In recent years, open-water blooms were more widespread than previously experienced, and even occurred in the northern Bering Sea during 2018–2019. A progression to more open water blooms in a future warmer climate will influence the availability of basal resources for pelagic and benthic consumers.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138839871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interannual differences in sea ice regime in the north-western Barents Sea cause major changes in summer pelagic production and export mechanisms","authors":"Martí Amargant-Arumí ,&nbsp;Oliver Müller ,&nbsp;Yasemin V. Bodur ,&nbsp;Iliana-V. Ntinou ,&nbsp;Tobias Vonnahme ,&nbsp;Philipp Assmy ,&nbsp;Doreen Kohlbach ,&nbsp;Melissa Chierici ,&nbsp;Elizabeth Jones ,&nbsp;Lasse M. Olsen ,&nbsp;Tatiana M. Tsagaraki ,&nbsp;Marit Reigstad ,&nbsp;Gunnar Bratbak ,&nbsp;Rolf Gradinger","doi":"10.1016/j.pocean.2023.103178","DOIUrl":"10.1016/j.pocean.2023.103178","url":null,"abstract":"<div><p>The Barents Sea is a highly dynamic and productive marine ecosystem and a hotspot of global warming. Variability in sea ice extent is a common feature in the Barents Sea with substantial movements of the sea ice edge on short-term, seasonal to interannual time scales. Historically the northern Barents Sea (north of 75°N) has been ice-covered in winter, but recently it has become the area with most winter ice loss in the Arctic, and year-round ice-free conditions are predicted for the second half of the 21st century. These environmental changes have significant implications for the marine ecosystem. In this study we used contrasting sea ice regimes in August 2018 and August 2019 to explore the response of phytoplankton and bacterial production, microbial abundance, and vertical carbon flux in the north-western Barents Sea (between 76°N and 83°N) to the variability of sea ice. While the study area was ice-free in August 2018, extensive areas north of 79°N were ice-covered in 2019. When the northern parts of the transect were still ice covered, diatoms and other larger phytoplankton were dominant and highest abundances were observed following the receding ice edge. In contrast, under ice-free conditions in 2018, the pelagic ecosystem resembled a post-bloom stage of the seasonal succession with higher abundance of small phytoplankton and heterotrophic protists and low vertical flux throughout the water column. While phytoplankton biomass, bacterial production and downward vertical flux of particulate organic carbon in the upper 60 m were on average higher in 2019, primary production and carbon export below the euphotic layer were comparable between both years. However, overall highest primary production, bacterial production and abundance of both photosynthetic and heterotrophic microorganisms were observed in surface waters (upper 30 m) in 2019, connected to the retreating ice edge, where also vertical particle flux was higher and characterized by a strong attenuation curve. The results clearly demonstrate that differences in ice cover affect the phenology of pelagic primary production and associated biological processes in the Barents Sea.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138438529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From winter to late summer in the northwestern Barents Sea shelf: Impacts of seasonal progression of sea ice and upper ocean on nutrient and phytoplankton dynamics","authors":"Zoe Koenig ,&nbsp;Morven Muilwijk ,&nbsp;Håkon Sandven ,&nbsp;Øyvind Lundesgaard ,&nbsp;Philipp Assmy ,&nbsp;Sigrid Lind ,&nbsp;Karen M. Assmann ,&nbsp;Melissa Chierici ,&nbsp;Agneta Fransson ,&nbsp;Sebastian Gerland ,&nbsp;Elizabeth Jones ,&nbsp;Angelika H.H. Renner ,&nbsp;Mats A. Granskog","doi":"10.1016/j.pocean.2023.103174","DOIUrl":"10.1016/j.pocean.2023.103174","url":null,"abstract":"<div><p>Strong seasonality is a key feature of high-latitude systems like the Barents Sea. While the interannual variability and long-term changes of the Barents Sea are well-documented, the seasonal progression of the physical and biological systems is less known, mainly due to poor accessibility of the seasonally ice-covered area in winter and spring. Here, we use an extensive set of physical and biological <em>in situ</em> observations from four scientific expeditions covering the seasonal progression from late winter to late summer 2021 in the northwestern Barents Sea, from fully ice-covered to ice-free conditions. We found that sea ice meltwater and the timing of ice-free conditions in summer shape the environment, controlling heat accumulation, light and nutrient availability, and biological activity vertically, seasonally, and meridionally. In March and May, the ocean north of the Polar Front was ice-covered and featured a deep mixed layer. Chlorophyll-<em>a</em> concentrations increased strongly from March to May along with greater euphotic depth, indicating the beginning of the spring bloom despite the absence of surface layer stratification. By July and in September, sea ice meltwater created a shallow low-density surface layer that strengthened stratification. In open water, chlorophyll-<em>a</em> maxima were found at the base of this layer as surface nutrients were depleted, while in the presence of ice, maxima were closer to the surface. Solar heating and the thickness of the surface layer increased with the number of ice-free days. The summer data showed a prime example of an Arctic-like space-for-time seasonal variability in the key physical and biological patterns, with the summer situation progressing northwards following sea ice retreat. The amount of sea ice melt (local or imported) has a strong control on the conditions in the northwestern Barents Sea, and the conditions in late 2021 resembled pre-2010 Arctic-like conditions with high freshwater content and lower ocean heat content.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0079661123002173/pdfft?md5=d7adaed2e37accb40d448239a322be80&pid=1-s2.0-S0079661123002173-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138567021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing net primary production in the northwestern Barents Sea using in situ, remote sensing and modelling approaches","authors":"Laura Castro de la Guardia ,&nbsp;Tania Hernández Fariñas ,&nbsp;Christian Marchese ,&nbsp;Martí Amargant-Arumí ,&nbsp;Paul G. Myers ,&nbsp;Simon Bélanger ,&nbsp;Philipp Assmy ,&nbsp;Rolf Gradinger ,&nbsp;Pedro Duarte","doi":"10.1016/j.pocean.2023.103160","DOIUrl":"10.1016/j.pocean.2023.103160","url":null,"abstract":"<div><p>The northwestern Barents Sea (NW-BS) is a highly productive region within the transitional zones of an Atlantic to Arctic-dominated marine ecosystem. The steep latitudinal gradients in sea ice concentration, Atlantic and Arctic Water, offer an opportunity to test hypotheses on physical drivers of spatial and temporal variability of net primary production (NPP). However, quantifying NPP in such a large ocean region can be challenged by the lack of in situ measurements with high spatial and temporal resolution, and gaps in remote sensing estimates due to the presence of clouds and sea ice, and assumptions regarding the depth distribution of alga biomass. Without reliable data to evaluate models, filling these gaps with numerical models is limited by the model representation of the physical environment and its assumptions about the relationships between NPP and its main limiting factors. Hence, within the framework of the Nansen Legacy Project, we combined in situ measurements, remote sensing, and model simulations to constrain the estimates of phytoplankton NPP in the NW-BS. The region was subdivided into Atlantic, Subarctic, and Arctic subregions on the basis of different phytoplankton phenology. In 2004 there was a significant regime change in the Atlantic subregion that resulted in a step-increase in NPP in tandem with a step-decrease in sea ice concentration. Contrary to results from other Arctic seas, this study does not find any long term trends in NPP despite changes in the physical environment. Mixing was the main driver of simulated annual NPP in the Atlantic subregion, while light and nutrients drove annual NPP in the Subarctic and Arctic subregions. The multi-source estimate of annual NPP ranged 79–118<!--> <!-->gC<!--> <!-->m⁻² <!-->yr⁻¹ in the Atlantic, 74–82<!--> <!-->gC<!--> <!-->m⁻² <!-->yr⁻¹ in the Subarctic, and 19–47<!--> <!-->gC<!--> <!-->m⁻² <!-->yr⁻¹ in the Arctic. The total NPP in the NW-BS region was estimated between 15 and 48<!--> <!-->Tg<!--> <!-->C<!--> <!-->yr⁻¹, which is 15–50% of the total NPP needed to sustain three of the most harvested fish species north of 62°N (roughly <!--> <!-->90<!--> <!-->Tg<!--> <!-->C<!--> <!-->yr⁻¹). This research shows the importance of continuing to strive for better regional estimates of NPP.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0079661123002033/pdfft?md5=c724f3cab7a09a70dc29dc59406673f2&pid=1-s2.0-S0079661123002033-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138293405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gelatinous zooplankton off the Northeast Greenland coast","authors":"Karol Mazanowski ,&nbsp;Maciej K. Mańko ,&nbsp;Eva F. Møller ,&nbsp;Agata Weydmann-Zwolicka","doi":"10.1016/j.pocean.2023.103173","DOIUrl":"10.1016/j.pocean.2023.103173","url":null,"abstract":"<div><p>Gelatinous zooplankton are useful indicators of climate-driven shifts in the ocean; hence our study goal was to determine their diversity and distribution in the poorly investigated area of the Northeast Greenland shelf and adjacent waters. Zooplankton samples were collected vertically using a MultiNet in August and September 2017, at 9 stations along two transects: northern and southern. Eleven taxa were identified, of which <em>Plotocnide borealis</em> had the largest share within the assemblage in both transects. Gelatinous zooplankton biodiversity was the highest in the north. The local bathymetry and hydrology both shaped the distribution of the gelatinous zooplankton, leading to the emergence of three ecological groups: 1) taxa typically associated with, or found exclusively, in the intermediate, colder shelf waters (e.g. <em>Plotocnide borealis</em>); 2) organisms associated with higher temperatures and greater depths, mainly of the off-shelf waters (e.g. <em>Aglantha digitale</em>); 3) organisms whose distribution depended mainly on salinity and oxygen saturation (e.g. <em>Aeginopsis laurentii</em>). Additionally, <em>A. digitale</em> was associated with the presence of the warmer waters of Atlantic origin, the presence of which on both sides of the Fram Strait allowed to compare our findings with better studied gelatinous zooplankton from the West Spitsbergen Current, leading to the conclusion that the existent evidence of progressing Atlantification suggests that such impacts might also be expected off the Northeast Greenland coast.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0079661123002161/pdfft?md5=b955357787bd88beaac409a1468d8ae1&pid=1-s2.0-S0079661123002161-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138292924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal and regional variability of model-based zooplankton biomass in the Salish Sea and evaluation against observations","authors":"Karyn D. Suchy ,&nbsp;Elise Olson ,&nbsp;Susan E. Allen ,&nbsp;Moira Galbraith ,&nbsp;BethElLee Herrmann ,&nbsp;Julie E. Keister ,&nbsp;R. Ian Perry ,&nbsp;Akash R. Sastri ,&nbsp;Kelly Young","doi":"10.1016/j.pocean.2023.103171","DOIUrl":"10.1016/j.pocean.2023.103171","url":null,"abstract":"<div><p>We used a three-dimensional coupled biophysical model to examine zooplankton dynamics in the Salish Sea, NE Pacific. First, we evaluated the two zooplankton classes of the SalishSeaCast model using a transboundary zooplankton dataset comprised of observation data from the Canadian and United States waters of the Salish Sea from 2015 to 2019. Model zooplankton classes correspond to micro- and meso-zooplankton whose biomass is tightly coupled to phytoplankton through modelled food web dynamics (Z1) and mesozooplankton with life cycle-based seasonal grazing impacts (Z2). Overall, the model effectively captured seasonal patterns in observed biomass, although with slightly higher biomass estimates for both Z1 and Z2 (Bias = 0.10 and 0.08 g C m⁻², respectively). Model fit varied regionally, with a weaker model fit being observed in nearshore regions. In addition, an autumn peak in Z2 was observed in the model, but not in the observations, suggesting some seasonal variations in model fit. Following the model evaluation, we used the model to determine seasonal and regional patterns of zooplankton grazing. Seasonally, the main peak in modelled zooplankton biomass increased in April or May in most of the regions defined within the Salish Sea and was driven by grazing on diatoms. Regionally, depth-integrated zooplankton biomass was consistently highest in areas adjacent to regions of strong tidal mixing. In addition, model-based zooplankton grazing was highest in the tidally mixed regions where phytoplankton biomass was high due to advection into the region despite low primary productivity. Our model-based results provide an opportunity to examine bottom-up food web processes at spatio-temporal scales not achievable with <em>in situ</em> sampling and help to elucidate key drivers of lower trophic level dynamics within the Salish Sea.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0079661123002148/pdfft?md5=7dde40cb1f55f2c9fc24a6fbdc685934&pid=1-s2.0-S0079661123002148-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135669292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of oceanographic conditions during the North Atlantic EXport processes in the ocean from RemoTe sensing (EXPORTS) field campaign","authors":"Leah Johnson ,&nbsp;David A. Siegel ,&nbsp;Andrew F. Thompson ,&nbsp;Erik Fields ,&nbsp;Zachary K. Erickson ,&nbsp;Ivona Cetinic ,&nbsp;Craig M. Lee ,&nbsp;Eric A. D'Asaro ,&nbsp;Norman B. Nelson ,&nbsp;Melissa M. Omand ,&nbsp;Michaela Sten ,&nbsp;Shawnee Traylor ,&nbsp;David P. Nicholson ,&nbsp;Jason R. Graff ,&nbsp;Deborah K. Steinberg ,&nbsp;Heidi M. Sosik ,&nbsp;Ken O. Buesseler ,&nbsp;Mark A. Brzezinski ,&nbsp;Inia Soto Ramos ,&nbsp;Filipa Carvalho ,&nbsp;Stephanie A. Henson","doi":"10.1016/j.pocean.2023.103170","DOIUrl":"10.1016/j.pocean.2023.103170","url":null,"abstract":"<div><p>This manuscript presents an overview of NASA’s EXport Processes in the Ocean from Remote Sensing 2021 Field Campaign in the North Atlantic (EXPORTS NA) and provides quantitative and dynamical descriptions of the physical processes modulating water transformations during the study. A major programmatic goal was to conduct the sampling in a Lagrangian mode so that ocean ecological and biogeochemical changes can be observed independent from physical advective processes. To accomplish this goal, EXPORTS NA conducted a multi-ship, multi-asset field sampling program within a retentive, anticyclonic mode water eddy. Beneath depths of ∼ 100 m, Lagrangian sampling assets remained within the eddy core waters (ECWs) throughout the experiment, demonstrating that the ECWs within the mode water eddy were retentive. However, strong westerly winds from four storm events deepened the mixed layer (ML) of the surface core waters (SCWs) above the eddy’s mode water core by 25–40 m and exchanged some of the SCWs with surface waters outside of the eddy via Ekman transport. Estimates of flushing times ranged from 5 to 8 days, with surface exchange fractions ranging from 20 to 75 % and were consistent with particle tracking advected by combined geostrophic and Ekman velocities. The relative contributions of horizontal and vertical advection on changes in ECW tracers depended on the horizontal and vertical gradients of that tracer. For example, horizontal advection played a large role in ECW salinity fluxes, while vertical entrainment played a larger role in the fluxes of nutrients into SCW ML. Each storm injected nutrients and low oxygen waters into the ML, after which the surface ocean ecosystem responded by reducing nutrient concentrations and increasing %O₂ saturation levels. Overall, ECW values of chlorophyll and POC were the largest at the onset of the field program and decreased throughout the campaign. The analysis presented provides a physical oceanographic context for the many measurements made during the EXPORTS NA field campaign while illustrating the many challenges of conducting a production-flux experiment, even in a Lagrangian frame, and the inherent uncertainties of interpreting biological carbon pump observations that were collected in a Eulerian frame of reference.</p></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135670047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}