Progress in Oceanography最新文献

{"title":"Seasonal variations of the cold intermediate layer on the Newfoundland and Labrador Shelf","authors":"H.J. Andres,&nbsp;N. Soontiens,&nbsp;J. Penney,&nbsp;F. Cyr","doi":"10.1016/j.pocean.2024.103379","DOIUrl":"10.1016/j.pocean.2024.103379","url":null,"abstract":"<div><div>Across the Newfoundland and Labrador (NL) continental shelf, sub-surface temperatures remain below 0°C throughout the summer, when the surface is much warmer. This oceanographic feature is known as a cold intermediate layer (CIL), and its properties are assessed annually in the region to support ocean climate research and fisheries management. Monitoring in this region is either too infrequent or too sparse spatially to provide a detailed picture of sub-annual variations, so the GLORYS12 global ocean reanalysis is used for this purpose. GLORYS12 is shown to reproduce both the signs and magnitudes of inter-annual variations in CIL area on NL Shelf transects, although the magnitude of the seasonal cycle may be under-estimated.</div><div>GLORYS12 indicates that sub-zero water volume is maximized across the region during March and decreases with time, beginning in the south and proceeding north. CIL minima are reached between November to December at most shelf locations, proceeding in the opposite direction. Stratification triggered by surface freshwater is an important contributor to CIL seasonal changes on all transects on the NL Shelf. While the CIL area tends to gradually erode throughout the summer, the downstream advection of CIL water from more northern transects leads to the development of secondary CIL area maxima during late August to early September on the Newfoundland component of the shelf. Onshore intrusions either at the shelf break or via cross-shelf troughs contribute to the erosion of CIL area from below at some transects, although this effect may be exaggerated in the model.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103379"},"PeriodicalIF":3.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655865","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":"Community composition and distribution of epi- and suprabenthic macrofauna in the bathyal, abyssal, and hadal zones of the northern North Pacific","authors":"Angelika Brandt ,&nbsp;Anna M. Jażdżewska ,&nbsp;Stefanie Kaiser ,&nbsp;Magdalena Błażewicz ,&nbsp;Sarah Gerken ,&nbsp;Kamila Głuchowska ,&nbsp;Andreas Kelch ,&nbsp;Mathis Preikschardt ,&nbsp;Henry Knauber ,&nbsp;Katharina Kohlenbach ,&nbsp;Hanieh Saeedi ,&nbsp;Anne Helene S. Tandberg ,&nbsp;Davide Di Franco","doi":"10.1016/j.pocean.2024.103376","DOIUrl":"10.1016/j.pocean.2024.103376","url":null,"abstract":"<div><div>The deep sea, Earth’s largest biome, harbors numerous unknown species. Prior to the AleutBio (Aleutian Trench Biodiversity Studies) expedition from July to September 2022, the Northeast (NE) Pacific at abyssal and hadal depths was virtually unexplored. Our study presents new findings from the AleutBio project on the macrofaunal composition of the Bering Sea (BS) and Aleutian Trench (AT) collected by means of an epibenthic sledge (EBS), comparing these results with data from the Kuril-Kamchatka Trench (KKT) and the Northwest (NW) Pacific. Additionally, we examine variations in macrofaunal composition and abundance across different regions and depths. A biogeographic gap analysis using data from the Ocean Biodiversity Information System (OBIS) and the Global Biodiversity Information Facility (GBIF) found that, out of 170,627 occurrence records from the North Pacific and Bering Sea, only 153 were from depths below 3,500 m. The AleutBio project addressed this gap by significantly expanding the dataset with 36,499 new records collected during the expedition using an EBS. Nearly 98% of the specimens were from five phyla: Arthropoda, Annelida, Mollusca, Echinodermata, and Nematoda, with Polychaeta, Copepoda, and Nematoda being the most abundant taxa. Although the number of individuals varied between stations, there was no significant decrease in abundance with increasing depth, and some hadal stations had similar numbers of invertebrates as abyssal stations. Regional differences were observed, with Polychaeta and Nematoda being dominant in the BS, and Copepoda more prevalent at western abyssal stations. Depth emerged as the key factor influencing macrofaunal distribution, with distinct patterns across bathyal, abyssal, and hadal depths. Comparisons with other NW Pacific regions, like the Sea of Japan and the Sea of Okhotsk, show that depth and water body isolation play crucial roles in shaping faunal communities. AleutBio’s extensive sampling below 3,500 m has vastly increased available data, aiding in the understanding and conservation of deep-sea biodiversity. While certain taxa showed patchy distributions, no significant differences in faunal composition were found between geographic areas or depth zones. These findings underscore the dynamic nature of deep-sea ecosystems and highlight the importance of depth in shaping macrofaunal communities, emphasizing the need for continued research in these fascinating environments.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"230 ","pages":"Article 103376"},"PeriodicalIF":3.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701035","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":"Multidecadal decline in sea ice meltwater volume and Pacific Winter Water salinity in the Bering Sea revealed by ocean observations","authors":"Vigan Mensah ,&nbsp;Yen-Chen Chen ,&nbsp;Daiki Nomura ,&nbsp;Hiromichi Ueno ,&nbsp;Hwa Chien ,&nbsp;Kay I. Ohshima","doi":"10.1016/j.pocean.2024.103377","DOIUrl":"10.1016/j.pocean.2024.103377","url":null,"abstract":"<div><div>Large amounts of freshwater and nutrients pass through the Bering Strait to the Arctic Ocean, making the Bering Sea a crucial marginal sea of the North Pacific Ocean. The hydrography and biological production of the Bering Sea are strongly influenced by the amount of sea ice produced and melted. The sea ice extent and production exhibited large interannual variability but no visible trend until 2016 when a strong decrease began. However, records of sea ice before 1979 and the beginning of satellite-based estimates do not exist. In this paper, we devised a methodology using historical temperature and salinity data, supplemented by historical oxygen isotope (δ¹⁸O) data, to estimate sea ice melt and its temporal variability in the Bering Sea from 1950 onward. Our results, consistent with estimates of sea ice thickness, indicate that the sea ice melt volume has declined significantly —following lower sea ice extent and production— with a decrease between 35 and 50 km³ (from 442 km³) between pre-1980 and post-1980 climatologies. In particular, our meltwater time series reveals a decline of 160 km³ between 2012 and 2018, which also reflects the strong decrease in sea ice volume between 2016 and 2018 that numerous previous studies have highlighted. We also evaluated the change in the salinity of the Pacific Winter Water (PWW), whose formation is also related to sea ice production. The time series of PWW salinity exhibits a strong decreasing trend, with a freshening of about 0.3 between the mid-1950s and the mid-2010s, that we attribute to a combination of a reduced sea ice production and the freshening of the Alaskan Coastal Current water. The decline in meltwater volume and PWW salinity that we observed strongly influences the stratification over the Bering shelf, with a significant weakening of the stratification in coastal polynya regions, and a stronger and increasingly temperature-controlled stratification in the rest of the shelf. These changes could have adverse consequences on the biological productivity of the northern Bering Sea.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"230 ","pages":"Article 103377"},"PeriodicalIF":3.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701001","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":"Reduced phytoplankton biomass in a subtropical plume-upwelling system induced by typhoons Bailu and Podul","authors":"Zhuyin Tong ,&nbsp;Lingqi Ma ,&nbsp;Shujie Cai ,&nbsp;Zhaoyun Chen ,&nbsp;Lei Wang ,&nbsp;Mingwang Xiang ,&nbsp;Rui Huang ,&nbsp;Meilin Wu ,&nbsp;Wupeng Xiao ,&nbsp;Bangqin Huang","doi":"10.1016/j.pocean.2024.103375","DOIUrl":"10.1016/j.pocean.2024.103375","url":null,"abstract":"<div><div>Phytoplankton responses to typhoons are pivotal for understanding the impact of climate change on marine biodiversity and productivity, yet current literature, focusing on typhoon-induced biomass increases from nutrient dynamics, might overlook the complexity of plume-upwelling interactions during such events. This study, therefore, examines the sequential impact of Typhoons Bailu and Podul on phytoplankton biomass and community structure in the northern South China Sea, a region where the interplay of riverine discharges and oceanic upwelling shapes the ecological landscape. Employing a combination of in-situ hydrographic measurements, pigment analysis, and satellite data, we tracked the pre- and post-typhoon phytoplankton dynamics, capturing a detailed picture of their response to the rapid hydrodynamic changes induced by these meteorological disturbances. Prior to Typhoon Bailu, a synergetic interaction between the Pearl River plume and coastal upwelling resulted in a diatom-rich phytoplankton assemblage. The passage of Typhoon Bailu followed by Typhoon Podul uncoupled this synergy, leading to phosphate scarcity and a notable decline in overall phytoplankton biomass. This decoupling favored the proliferation of smaller phytoplankton such as <em>Synechococcus</em> and haptophytes_T8, indicating a shift towards a community adapted to phosphate-poor environments. The distinct phytoplankton response patterns observed in this study not only challenge existing paradigms about typhoon impacts on marine productivity but also highlight the complex and potentially transformative effects of typhoon-induced hydrodynamic alterations, although whether the pattern of biomass reduction is generalizable to all similar typhoon events remains uncertain. These insights are essential for modeling the ecological ramifications of such disturbances, which is becoming increasingly important as the frequency and intensity of extreme weather events continue to rise.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103375"},"PeriodicalIF":3.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655937","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":"C:N stoichiometry and the fate of organic carbon in ecosystems of the northwest Pacific Ocean","authors":"Chuanli Zhang ,&nbsp;Yaoyao Wang ,&nbsp;Rong Bi ,&nbsp;Ulrich Sommer ,&nbsp;Guodong Song ,&nbsp;Zhaohui Chen ,&nbsp;Feng Lin ,&nbsp;Jing Zhang ,&nbsp;Meixun Zhao","doi":"10.1016/j.pocean.2024.103372","DOIUrl":"10.1016/j.pocean.2024.103372","url":null,"abstract":"<div><div>Phytoplankton elemental composition regulates the efficiency of energy and material transfer in the interface between phytoplankton and their consumers. The ratio of particulate organic carbon to particulate organic nitrogen (POC:PON) shows considerable regional deviations from the canonical Redfield ratio in the global surface ocean. However, in certain oceanic regions such as the northwest Pacific Ocean (NWPO) POC:PON distribution and its ecological significance remain uncertain. We investigated surface ocean POC:PON distributions at 66 stations in the NWPO, and quantified the correlations between POC:PON and multiple biotic and abiotic factors including sea surface temperature (SST), nutrient concentrations and multiple lipid biomarkers (fatty acids and sterols), by combining correlation analyses and generalized additive models. POC:PON (range: 3.53–14.18 M ratios; median: 6.89) was overall higher in the (sub)tropical biome than that in the high-latitude biome. In the entire study region, SST, nutrient concentration and lipid-derived phytoplankton community structure explained 41 %, 33 % and 26 % of the variance in POC:PON, respectively, while the respective importance of each factor differed between the (sub)tropical and high-latitude biomes. Furthermore, we calculated the percentage of primary production consumed by herbivores (PPC; 54–156 %), showing a higher mean value (117 %) in the high-latitude biome and a lower one (92 %) in the (sub)tropical biome. The spatial distribution pattern of PPC can be attributed to multiple factors, with PPC correlating negatively with SST and positively with lipid-based indicators of phytoplankton food quality and POC concentrations. The increase in SST may be associated with a reduced nitrogen content, resulting in lower PPC in the (sub)tropical biome. This study highlights the significance of SST and elemental and biochemical composition of phytoplankton in regulating the transfer of organic carbon to herbivores in the NWPO.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103372"},"PeriodicalIF":3.8,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655936","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":"Global characterization of modelled micronekton in biophysically defined provinces","authors":"S. Albernhe ,&nbsp;T. Gorgues ,&nbsp;P. Lehodey ,&nbsp;C. Menkes ,&nbsp;O. Titaud ,&nbsp;S. Magon De La Giclais ,&nbsp;A. Conchon","doi":"10.1016/j.pocean.2024.103370","DOIUrl":"10.1016/j.pocean.2024.103370","url":null,"abstract":"<div><div>Micronekton are the mid-trophic level of the ecosystem and contribute to active carbon export to the deep ocean through diel vertical migrations. Better characterization of micronekton functional groups depending on relationships to environmental variables is useful for the management of marine resources, the conservation of biodiversity and a better understanding of climate change impacts. For this purpose, regionalization of global ocean into homogeneous provinces is an approach that is generating increasing interest. However, published regionalizations efforts (i) derived from environmental forcings, that do not specifically focus on micronekton and (ii) derived from acoustic backscatter, which do not allow direct estimates of micronekton biomass. Here, we propose to fill the gap between biophysical regionalizations and micronekton biomass. We notably defined biophysical biomes using global environmental variables known to affect micronekton: temperature of the epipelagic layer, temperature stratification, and net primary production (NPP). Six biophysical biomes were defined with a clustering method. A characterization of these biophysical biomes with simulated micronekton from the SEAPODYM-LMTL model displayed biome-specific relationships between biomass and the environmental variables used in the clustering (i.e. biomasses mostly structured by NPP and temperature). Biophysical biomes also displayed specific vertical structures suggested by modelled micronekton functional groups ratios. Then, a validation of biophysical biomes’ boundaries was performed to identify potential vertical structure reorganization in acoustic backscattering response from adjacent biomes. The regionalization identified homogeneous areas in terms of acoustic vertical structure, which were also different between adjacent biomes. Finally, a comparison with another biomes’ definition computed from micronekton biomasses suggested that environmental variables can account for only some of the variability of the micronekton structures.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103370"},"PeriodicalIF":3.8,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655938","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":"Heterogeneous Sources, Distribution, and removal processes of dissolved black carbon from East China Sea shelf to open ocean of Northwest Pacific","authors":"Xi Zhang ,&nbsp;Yasong Wang ,&nbsp;Zhiliang Liu ,&nbsp;Bilin Liu ,&nbsp;Weichao Wu ,&nbsp;Liang Liu ,&nbsp;Ding He ,&nbsp;Yunping Xu","doi":"10.1016/j.pocean.2024.103374","DOIUrl":"10.1016/j.pocean.2024.103374","url":null,"abstract":"<div><div>Absract: Dissolved black carbon (DBC) can be transported from land to the ocean, representing a significant slow-cycling component in the global carbon cycle. However, the source, distribution, and degradation of DBC in the ocean are not well understood. In this study, water samples were collected from the East China Sea (ECS) shelf to the Northwest Pacific Ocean. The benzene polycarboxylic acid (BPCA) method and ultraviolet–visible spectroscopy were used to analyze DBC and dissolved organic matter, respectively. The concentration of DBC and the (B6CA + B5CA)/BPCAs ratio in surface water showed a decreasing trend from the ECS inner shelf towards the open ocean. This trend indicates the preferential removal of condensed aromatic compounds by photodegradation, while also implicating dilution by open ocean water as a significant factor contributing to the reduction of DBC concentrations. A significant negative correlation between DBC concentration and salinity was observed in surface water samples (r =  − 0.88; p &lt; 0.01). However, this relationship weakened and disappeared in offshore samples, suggesting a reduced influence of riverine inputs. Furthermore, vertical profiles of water samples (0 – 1000 m) revealed a decrease in DBC concentrations and an increase in the ratio of (B6CA + B5CA)/BPCAs, indicating the preferential photodegradation of condensed aromatic DBC molecules in the euphotic zone and the selective accumulation of these molecules in the ocean interior. The DBC flux into the Northwest Pacific Ocean was estimated to be 1.46 Tg/year with 51.7 to 73.1 % removed through photodegradation, while the remaining DBC was either transported into the deep ocean or biodegraded. Given the important role of photodegradation in regulating the DBC flux in the Northwest Pacific Ocean, we recommend further research into its impact on the refractory carbon cycle in global oceans.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103374"},"PeriodicalIF":3.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586786","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":"Ice algae as supplementary food rather than major energy source for the Barents sea zooplankton community","authors":"Doreen Kohlbach ,&nbsp;Haakon Hop ,&nbsp;Anette Wold ,&nbsp;Katrin Schmidt ,&nbsp;Lukas Smik ,&nbsp;Simon T. Belt ,&nbsp;Matthias Woll ,&nbsp;Martin Graeve ,&nbsp;Lucie Goraguer ,&nbsp;Øyvind Foss ,&nbsp;Philipp Assmy","doi":"10.1016/j.pocean.2024.103368","DOIUrl":"10.1016/j.pocean.2024.103368","url":null,"abstract":"<div><div>The Barents Sea is a hotspot for environmental change due to global warming. These changes impact the structure and functioning of the marine ecosystem year-round, and it is therefore important to gain knowledge on trophic relationships and the energy flow from primary producers, <em>i.e.</em>, ice algae (sympagic algae) and phytoplankton (pelagic algae) to consumers over the entire seasonal cycle. By using different lipid components as trophic markers, we provide seasonal coverage of the carbon and food-source composition of five of the most abundant and ecologically important zooplankton taxa inhabiting the Barents Sea: copepods, krill, amphipods, pteropods and chaetognaths. Based on the composition of algal-produced fatty acid (FA) markers, carbon-source composition of the zooplankton species reflected changes in the production and availability of food resources during different periods of the year. For example, relative proportions of the dinoflagellate/<em>Phaeocystis</em> FA marker 18:4(<em>n</em>-3) peaked during summer in <em>Calanus</em> copepods, the amphipod <em>Themisto abyssorum</em> and the chaetognath <em>Pseudosagitta maxima</em>, when the production of this FA reached maximum concentrations in phytoplankton. The composition of carnivory FAs (relative contribution of copepod-associated FAs, ratio 18:1(<em>n</em>-9)/18:1(<em>n</em>-7)) and the ratio of zoo- to phytosterols indicated that most grazers relied more on heterotrophic prey during polar night and spring while switching to a more algae-based diet during the summer. Based on source-specific highly branched isoprenoids (HBIs), sympagic carbon had generally a minor contribution to the nutrition of the zooplankton community, particularly during winter and spring when sympagic HBIs were virtually undetected in the animals. In contrast, sympagic HBI metabolites were detected in krill, amphipods and the pteropod <em>Clione limacina</em> during summer and autumn. The krill <em>Meganyctiphanes norvegica</em> was unique in terms of its HBI composition as the only species containing both sympagic and pelagic HBIs during spring. Our results indicate that the Barents Sea zooplankton community is largely based on pelagic carbon, while sympagic carbon is only supplementing species-specific diets, mostly during the second half of the year. This relatively low trophic dependency on sea-ice algae might be an indication of the resilience of this food web towards ongoing sea-ice decline that causes changes to the timing and availability of sympagic and pelagic carbon and food sources.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103368"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698137","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":"Pre-molt dispersal and use of marine protected areas by Southern Rockhopper Penguins (Eudyptes chrysocome) at the southernmost oceanic regions of South America","authors":"Samanta Dodino ,&nbsp;Ulises Balza ,&nbsp;Luciana Riccialdelli ,&nbsp;Michael J. Polito ,&nbsp;Klemens Pütz ,&nbsp;Andrea Raya Rey","doi":"10.1016/j.pocean.2024.103369","DOIUrl":"10.1016/j.pocean.2024.103369","url":null,"abstract":"<div><div>Marine Protected Areas (MPAs) are crucial for conserving marine biodiversity, and assessing the effectiveness of boundaries in protecting marine species is essential. In the Southwest Atlantic Ocean, four MPAs have been created. In this study we evaluate the use of these MPAs by Southern Rockhopper Penguins (<em>Eudyptes chrysocome</em>) that nest at Isla de los Estados, Argentina during the pre-molt period in February and March 2020 by combining geolocation sensor data and spatial analysis together with stable isotopes analysis (<em>δ</em>¹³C and <em>δ</em>¹⁵N) to assess their spatial and trophic niches. We recaptured 16 of 25 adults to which loggers had been attached (64 % recapture rate, 6 females and 10 males). Penguins dispersed mainly southward and used the MPAs as corridors towards feeding area such as the Antarctic Polar Frontal Zone (APFZ). We found no evidence of sex-specific spatial and trophic niche partitioning. To develop robust conservation strategies, future studies should span multiple years and enhanced sampling effort to comprehensively explore the pre-molt trophic ecology and at-sea distribution of Southern Rockhopper Penguins.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103369"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655933","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":"Modelling global mesozooplankton biomass using machine learning","authors":"Kailin Liu ,&nbsp;Zhimeng Xu ,&nbsp;Xin Liu ,&nbsp;Bangqin Huang ,&nbsp;Hongbin Liu ,&nbsp;Bingzhang Chen","doi":"10.1016/j.pocean.2024.103371","DOIUrl":"10.1016/j.pocean.2024.103371","url":null,"abstract":"<div><div>Mesozooplankton are a crucial link between primary producers and higher trophic levels and play a vital role in marine food webs, biological carbon pumps, and sustaining fishery resources. However, the global distribution of mesozooplankton biomass and the relevant controlling mechanisms remain elusive. We compared four machine learning algorithms (Boosted Regression Trees, Random Forest, Artificial Neural Network, and Support Vector Machine) to model the spatiotemporal distributions of global mesozooplankton biomass. These algorithms were trained on a compiled dataset of published mesozooplankton biomass observations with corresponding environmental predictors from contemporaneous satellite observations (temperature, chlorophyll, salinity, and mixed layer depth). We found that Random Forest achieved the best predictive accuracy with <em>R²</em> and <em>RMSE</em> (Root Mean Standard Error) of 0.57 and 0.39, respectively. Also, the global distribution of mesozooplankton biomass predicted by the Random Forest model was more consistent with the observational data than other models. We used the Random Forest model to create a global map of mesozooplankton biomass which serves as a reference for validating process-based ecosystem models. The model outputs confirm that environmental factors, especially surface Chl <em>a</em>, a proxy for prey availability, significantly correlate with the spatiotemporal distribution of mesozooplankton biomass. The scaling relationship between the mesozooplankton biomass and Chl <em>a</em> can be used as an emergent constraint for model validation and development. Moreover, our model predicts that the global total mesozooplankton biomass will decrease by 3% by the end of this century under the “business-as-usual” scenarios, potentially reducing fishery production and carbon sequestration. Our study contributes to predicting global mesozooplankton biomass and provides deep insights into the underlying environmental impacts on the distribution of mesozooplankton biomass.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103371"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552124","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}