Pub Date : 2024-11-17DOI: 10.1016/j.pocean.2024.103383
Bo Yang , Chris Langdon
The skin of the ocean is often slightly cooler than the surface mixed layer due to net surface heat loss (cool skin effect), and sometimes slightly warmer in areas with extreme solar radiation (warm layer effect). In previous work (Yang et al., 2022), with the skin temperature correction term (ΔT) derived from the fifth generation European Center for Medium-Range Weather Forecasts Reanalysis (ERA5) and oxygen (O2) data from three Argo profiling floats, we showed that skin temperature correction is critical for air-sea O2 flux calculation. In this work, we applied the same method to the World Ocean Atlas 2018 (WOA2018) dataset with two widely used air-sea gas exchange models (an empirically derived quadratic bulk flux model W14, and a mechanistic bubble-mediated model E19), to evaluate the influence of skin temperature correction on large-scale air-sea O2 flux estimate. To avoid the influence of sea ice on air-sea gas exchange (and possibly on the ERA5 reanalysis), we limited our analysis between 50°S and 50°N. The result revealed that for both W14 and E19 models the skin temperature correction lowered annual sea-to-air O2 flux between 50°S and 50°N by 25 % for the E19 model and by 22 % for the W14 model. Larger ΔT (further from zero), higher temperature, higher wind speed, and larger O2 concentration difference across the air-sea interface led to larger difference in O2 fluxes calculated with and without the skin temperature correction. With the E19 model, using the ERA5-based ΔT for areas between 50°S and 50°N and a fixed ΔT of −0.17 K for high latitude areas (50°N-90°N and 50°S-90°S), we made an estimate of O2-based global air-to-sea carbon flux of 3.84 Pg C yr−1 (using O2 to C ratio of 1.45 from Hedges et al., 2002), which was comparable to other latest estimates.
{"title":"The influence of applying skin temperature corrections to gas exchange models on air-sea oxygen flux estimates","authors":"Bo Yang , Chris Langdon","doi":"10.1016/j.pocean.2024.103383","DOIUrl":"10.1016/j.pocean.2024.103383","url":null,"abstract":"<div><div>The skin of the ocean is often slightly cooler than the surface mixed layer due to net surface heat loss (cool skin effect), and sometimes slightly warmer in areas with extreme solar radiation (warm layer effect). In previous work (<span><span>Yang et al., 2022</span></span>), with the skin temperature correction term (ΔT) derived from the fifth generation European Center for Medium-Range Weather Forecasts Reanalysis (ERA5) and oxygen (O<sub>2</sub>) data from three Argo profiling floats, we showed that skin temperature correction is critical for air-sea O<sub>2</sub> flux calculation. In this work, we applied the same method to the World Ocean Atlas 2018 (WOA2018) dataset with two widely used air-sea gas exchange models (an empirically derived quadratic bulk flux model W14, and a mechanistic bubble-mediated model E19), to evaluate the influence of skin temperature correction on large-scale air-sea O<sub>2</sub> flux estimate. To avoid the influence of sea ice on air-sea gas exchange (and possibly on the ERA5 reanalysis), we limited our analysis between 50°S and 50°N. The result revealed that for both W14 and E19 models the skin temperature correction lowered annual sea-to-air O<sub>2</sub> flux between 50°S and 50°N by 25 % for the E19 model and by 22 % for the W14 model. Larger ΔT (further from zero), higher temperature, higher wind speed, and larger O<sub>2</sub> concentration difference across the air-sea interface led to larger difference in O<sub>2</sub> fluxes calculated with and without the skin temperature correction. With the E19 model, using the ERA5-based ΔT for areas between 50°S and 50°N and a fixed ΔT of −0.17 K for high latitude areas (50°N-90°N and 50°S-90°S), we made an estimate of O<sub>2</sub>-based global air-to-sea carbon flux of 3.84 Pg C yr<sup>−1</sup> (using O<sub>2</sub> to C ratio of 1.45 from <span><span>Hedges et al., 2002</span></span>), which was comparable to other latest estimates.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"230 ","pages":"Article 103383"},"PeriodicalIF":3.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694103","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}
Pub Date : 2024-11-08DOI: 10.1016/j.pocean.2024.103373
Isaac Reister, Seth Danielson, Ana Aguilar-Islas
The biologically productive Northern Gulf of Alaska (NGA) continental shelf receives large inputs of freshwater from surrounding glaciated and non-glaciated watersheds, and a better characterization of the regional salinity spatiotemporal variability is important for understanding its fate and ecological roles. We here assess synoptic to seasonal distributions of freshwater pathways of the Copper River discharge plume and the greater NGA continental shelf and slope using observations from ship-based and towed undulating conductivity-temperature-depth (CTD) instruments, satellite imagery, and satellite-tracked drifters. On the NGA continental shelf and slope we find low salinities not only nearshore but also 100–150 km from the coast (i.e. average 0–50 m salinities less than 31.9, 31.3, and 30.8 in spring, summer, and fall respectively) indicating recurring mid-shelf and shelf-break freshwater pathways. Close to the Copper River, the shelf bathymetry decouples the spreading river plume from the direct effects of seafloor-induced steering and mixing, allowing iron- and silicic acid-rich river outflow to propagate offshore within a surface-trapped plume. Self-organized mapping analysis applied to true color satellite imagery reveals common patterns of the turbid river plume. We show that the Copper River plume is sensitive to local wind forcing and exerts control over water column stratification up to ∼100 km from the river mouth. Upwelling-favorable wind stress modifies plume entrainment and density anomalies and plume width. Baroclinic transport of surface waters west of the river mouth closely follow the influence of alongshore wind stress, while baroclinic transport east of the river mouth is additionally modified by a recurring or persistent gyre. Our results provide context for considering the oceanic fate of terrestrial discharges in the Gulf of Alaska.
具有生物生产力的北阿拉斯加湾（NGA）大陆架接受来自周围冰川和非冰川流域的大量淡水输入，更好地描述区域盐度时空变化特征对于了解淡水的去向和生态作用非常重要。在此，我们利用船载和拖曳式起伏电导率-温度-深度（CTD）仪器、卫星图像和卫星跟踪漂流器的观测数据，评估了铜河排放羽流和大 NGA 大陆架及斜坡淡水路径的同步至季节分布情况。在 NGA 大陆架和斜坡上，我们发现不仅近岸盐度低，而且距离海岸 100-150 公里处的盐度也很低（即春季、夏季和秋季 0-50 米处的平均盐度分别低于 31.9、31.3 和 30.8），这表明大陆架中部和大陆架断裂处的淡水通路经常出现问题。在铜河附近，陆架水深使扩散的河流羽流脱离了由海底引起的转向和混合的直接影响，从而使富含铁和硅酸的河流外流在海面束缚的羽流中向近海传播。应用于真彩卫星图像的自组织绘图分析揭示了浑浊河流羽流的共同模式。我们的研究表明，铜河羽流对当地风力十分敏感，并对距离河口 100 公里以内的水柱分层具有控制作用。有利于上涌的风力改变了羽流的夹带和密度异常以及羽流宽度。河口以西表层水的条带传输密切受沿岸风应力的影响，而河口以东的条带传输则受到反复出现或持续存在的涡旋的影响。我们的研究结果为考虑阿拉斯加湾陆地排放物的海洋归宿提供了背景。
{"title":"Perspectives on Northern Gulf of Alaska salinity field structure, freshwater pathways, and controlling mechanisms","authors":"Isaac Reister, Seth Danielson, Ana Aguilar-Islas","doi":"10.1016/j.pocean.2024.103373","DOIUrl":"10.1016/j.pocean.2024.103373","url":null,"abstract":"<div><div>The biologically productive Northern Gulf of Alaska (NGA) continental shelf receives large inputs of freshwater from surrounding glaciated and non-glaciated watersheds, and a better characterization of the regional salinity spatiotemporal variability is important for understanding its fate and ecological roles. We here assess synoptic to seasonal distributions of freshwater pathways of the Copper River discharge plume and the greater NGA continental shelf and slope using observations from ship-based and towed undulating conductivity-temperature-depth (CTD) instruments, satellite imagery, and satellite-tracked drifters. On the NGA continental shelf and slope we find low salinities not only nearshore but also 100–150 km from the coast (i.e. average 0–50 m salinities less than 31.9, 31.3, and 30.8 in spring, summer, and fall respectively) indicating recurring mid-shelf and shelf-break freshwater pathways. Close to the Copper River, the shelf bathymetry decouples the spreading river plume from the direct effects of seafloor-induced steering and mixing, allowing iron- and silicic acid-rich river outflow to propagate offshore within a surface-trapped plume. Self-organized mapping analysis applied to true color satellite imagery reveals common patterns of the turbid river plume. We show that the Copper River plume is sensitive to local wind forcing and exerts control over water column stratification up to ∼100 km from the river mouth. Upwelling-favorable wind stress modifies plume entrainment and density anomalies and plume width. Baroclinic transport of surface waters west of the river mouth closely follow the influence of alongshore wind stress, while baroclinic transport east of the river mouth is additionally modified by a recurring or persistent gyre. Our results provide context for considering the oceanic fate of terrestrial discharges in the Gulf of Alaska.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103373"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142643110","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}
Pub Date : 2024-11-07DOI: 10.1016/j.pocean.2024.103378
Julian P. McCreary Jr. , Theodore W. Burkhardt
Wind-driven equatorial Kelvin, Rossby, and Yanai waves are known to propagate vertically, as well as zonally, and packets of them can form “beams” that descend into the deep ocean along ray paths consistent with wave-group theory. Here, we obtain analytic solutions to a simplified ocean model that provide a more complete description of beam properties and dynamics than in previous studies.
The model is a linear, continuously stratified (LCS) system, in which the bottom is ignored and the background Vaisala frequency is constant. Solutions are forced by an oscillatory wind stress, , where: is or ; is confined to the region and increases and decreases monotonically; and enters the ocean as a body force with the profile . Under these restrictions, solutions can be represented as cosine transforms in that can be readily inverted.
Beam solutions for all three wave types have similar mathematical forms, and hence share many properties. Among other things, the solutions show how the structure and amplitude of beams depend on the above model parameters. Potential impacts of processes neglected in the solutions are noted.
众所周知，风驱动的赤道开尔文波、罗斯比波和柳井波可以垂直传播，也可以分区传播，它们的波包可以形成 "波束"，沿着符合波群理论的射线路径下降到深海。在这里，我们得到了一个简化海洋模型的解析解，与之前的研究相比，它对波束的特性和动力学提供了更完整的描述。该模型是一个线性、连续分层（LCS）系统，其中底部被忽略，背景维萨拉频率 Nb 为常数。求解受到振荡风应力的影响，即 τα=τoαXxexp-iσt ，其中：α 为 x 或 y；Xx 局限于 -L<x<L 区域，单调增减；τα 以 Zz=2/πh/z2+h2 的体力形式进入海洋。在这些限制条件下，解可以用 z 的余弦变换来表示，并且可以很容易地反转。所有三种波的波束解都具有相似的数学形式，因此有许多共同的特性。这三种波型的波束解都具有相似的数学形式，因此具有许多共同特性。除其他外，这些解显示了波束的结构和振幅如何取决于上述模型参数。此外，还指出了解法中忽略的过程的潜在影响。
{"title":"Analytic solutions for equatorial, Kelvin, Rossby, and Yanai beams","authors":"Julian P. McCreary Jr. , Theodore W. Burkhardt","doi":"10.1016/j.pocean.2024.103378","DOIUrl":"10.1016/j.pocean.2024.103378","url":null,"abstract":"<div><div>Wind-driven equatorial Kelvin, Rossby, and Yanai waves are known to propagate vertically, as well as zonally, and packets of them can form “beams” that descend into the deep ocean along ray paths consistent with wave-group theory. Here, we obtain analytic solutions to a simplified ocean model that provide a more complete description of beam properties and dynamics than in previous studies.</div><div>The model is a linear, continuously stratified (LCS) system, in which the bottom is ignored and the background Vaisala frequency <span><math><msub><mrow><mi>N</mi></mrow><mrow><mi>b</mi></mrow></msub></math></span> is constant. Solutions are forced by an oscillatory wind stress, <span><math><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mi>α</mi></mrow></msup><mo>=</mo><msubsup><mrow><mi>τ</mi></mrow><mrow><mi>o</mi></mrow><mrow><mi>α</mi></mrow></msubsup><mi>X</mi><mfenced><mrow><mi>x</mi></mrow></mfenced><mo>exp</mo><mfenced><mrow><mo>−</mo><mi>i</mi><mi>σ</mi><mi>t</mi></mrow></mfenced></mrow></math></span>, where: <span><math><mi>α</mi></math></span> is <span><math><mi>x</mi></math></span> or <span><math><mi>y</mi></math></span>; <span><math><mrow><mi>X</mi><mfenced><mrow><mi>x</mi></mrow></mfenced></mrow></math></span> is confined to the region <span><math><mrow><mo>−</mo><mi>L</mi><mo><</mo><mi>x</mi><mo><</mo><mi>L</mi></mrow></math></span> and increases and decreases monotonically; and <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mi>α</mi></mrow></msup></math></span> enters the ocean as a body force with the profile <span><math><mrow><mi>Z</mi><mfenced><mrow><mi>z</mi></mrow></mfenced><mo>=</mo><mfenced><mrow><mn>2</mn><mo>/</mo><mi>π</mi></mrow></mfenced><mi>h</mi><mo>/</mo><mfenced><mrow><msup><mrow><mi>z</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>+</mo><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfenced></mrow></math></span>. Under these restrictions, solutions can be represented as cosine transforms in <span><math><mi>z</mi></math></span> that can be readily inverted.</div><div>Beam solutions for all three wave types have similar mathematical forms, and hence share many properties. Among other things, the solutions show how the structure and amplitude of beams depend on the above model parameters. Potential impacts of processes neglected in the solutions are noted.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"230 ","pages":"Article 103378"},"PeriodicalIF":3.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701002","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}
Pub Date : 2024-11-06DOI: 10.1016/j.pocean.2024.103380
Nicolas Dupont , Joël M. Durant , Øystein Langangen , Leif Christian Stige
Global warming affects marine ecosystems by changing environmental conditions, ecosystem structure, and ecosystem functioning. In parts of the Arctic, increased sea temperature and decreased sea ice have led to a poleward expansion of boreal species and increased their interactions with native Arctic species. To investigate and quantify the changing interactions in an Arctic marine food web under new environmental conditions, we studied the interactions between key prey fish species in the seasonally ice-covered parts of the Barents Sea: adult polar cod (Boreogadus saida) and capelin (Mallotus villosus) and one of the major predators in the system: Atlantic cod (Gadus morhua). For this, we compared the predictive performance of threshold models predicting the abundance of adult polar cod as a function of Atlantic cod. Each model was associated with a hypothesis describing prey-predator interactions in different environmental conditions defined by threshold values of summer sea-ice or capelin stock biomass. The best predictive model showed that the predation effect of Atlantic cod on polar cod was strongest in years of low summer sea ice cover and low capelin stock biomass. Our results exemplified that Arctic species such as polar cod may experience increased predation pressure under climate change from boreal species such as Atlantic cod. These effects depend, however, not only on changes in abiotic drivers of species distributions, but also on food-web interactions involving mid-trophic level species such as capelin.
{"title":"Changes in prey-predator interactions in an Arctic food web under climate change","authors":"Nicolas Dupont , Joël M. Durant , Øystein Langangen , Leif Christian Stige","doi":"10.1016/j.pocean.2024.103380","DOIUrl":"10.1016/j.pocean.2024.103380","url":null,"abstract":"<div><div>Global warming affects marine ecosystems by changing environmental conditions, ecosystem structure, and ecosystem functioning. In parts of the Arctic, increased sea temperature and decreased sea ice have led to a poleward expansion of boreal species and increased their interactions with native Arctic species. To investigate and quantify the changing interactions in an Arctic marine food web under new environmental conditions, we studied the interactions between key prey fish species in the seasonally ice-covered parts of the Barents Sea: adult polar cod (<em>Boreogadus saida</em>) and capelin (<em>Mallotus villosus</em>) and one of the major predators in the system: Atlantic cod (<em>Gadus morhua</em>). For this, we compared the predictive performance of threshold models predicting the abundance of adult polar cod as a function of Atlantic cod. Each model was associated with a hypothesis describing prey-predator interactions in different environmental conditions defined by threshold values of summer sea-ice or capelin stock biomass. The best predictive model showed that the predation effect of Atlantic cod on polar cod was strongest in years of low summer sea ice cover and low capelin stock biomass. Our results exemplified that Arctic species such as polar cod may experience increased predation pressure under climate change from boreal species such as Atlantic cod. These effects depend, however, not only on changes in abiotic drivers of species distributions, but also on food-web interactions involving mid-trophic level species such as capelin.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103380"},"PeriodicalIF":3.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655866","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}
Pub Date : 2024-11-06DOI: 10.1016/j.pocean.2024.103379
H.J. Andres, N. Soontiens, J. Penney, F. Cyr
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.
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.
{"title":"Seasonal variations of the cold intermediate layer on the Newfoundland and Labrador Shelf","authors":"H.J. Andres, N. Soontiens, J. Penney, 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}
Pub Date : 2024-11-04DOI: 10.1016/j.pocean.2024.103376
Angelika Brandt , Anna M. Jażdżewska , Stefanie Kaiser , Magdalena Błażewicz , Sarah Gerken , Kamila Głuchowska , Andreas Kelch , Mathis Preikschardt , Henry Knauber , Katharina Kohlenbach , Hanieh Saeedi , Anne Helene S. Tandberg , Davide Di Franco
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.
{"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 , Anna M. Jażdżewska , Stefanie Kaiser , Magdalena Błażewicz , Sarah Gerken , Kamila Głuchowska , Andreas Kelch , Mathis Preikschardt , Henry Knauber , Katharina Kohlenbach , Hanieh Saeedi , Anne Helene S. Tandberg , 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}
Pub Date : 2024-11-04DOI: 10.1016/j.pocean.2024.103377
Vigan Mensah , Yen-Chen Chen , Daiki Nomura , Hiromichi Ueno , Hwa Chien , Kay I. Ohshima
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.
{"title":"Multidecadal decline in sea ice meltwater volume and Pacific Winter Water salinity in the Bering Sea revealed by ocean observations","authors":"Vigan Mensah , Yen-Chen Chen , Daiki Nomura , Hiromichi Ueno , Hwa Chien , 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 (δ<sup>18</sup>O) 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 km<sup>3</sup> (from 442 km<sup>3</sup>) between pre-1980 and post-1980 climatologies. In particular, our meltwater time series reveals a decline of 160 km<sup>3</sup> 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}
Pub Date : 2024-11-04DOI: 10.1016/j.pocean.2024.103375
Zhuyin Tong , Lingqi Ma , Shujie Cai , Zhaoyun Chen , Lei Wang , Mingwang Xiang , Rui Huang , Meilin Wu , Wupeng Xiao , Bangqin Huang
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 Synechococcus 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.
{"title":"Reduced phytoplankton biomass in a subtropical plume-upwelling system induced by typhoons Bailu and Podul","authors":"Zhuyin Tong , Lingqi Ma , Shujie Cai , Zhaoyun Chen , Lei Wang , Mingwang Xiang , Rui Huang , Meilin Wu , Wupeng Xiao , 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}
Pub Date : 2024-10-31DOI: 10.1016/j.pocean.2024.103372
Chuanli Zhang , Yaoyao Wang , Rong Bi , Ulrich Sommer , Guodong Song , Zhaohui Chen , Feng Lin , Jing Zhang , Meixun Zhao
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.
{"title":"C:N stoichiometry and the fate of organic carbon in ecosystems of the northwest Pacific Ocean","authors":"Chuanli Zhang , Yaoyao Wang , Rong Bi , Ulrich Sommer , Guodong Song , Zhaohui Chen , Feng Lin , Jing Zhang , 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}
Pub Date : 2024-10-31DOI: 10.1016/j.pocean.2024.103370
S. Albernhe , T. Gorgues , P. Lehodey , C. Menkes , O. Titaud , S. Magon De La Giclais , A. Conchon
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.
{"title":"Global characterization of modelled micronekton in biophysically defined provinces","authors":"S. Albernhe , T. Gorgues , P. Lehodey , C. Menkes , O. Titaud , S. Magon De La Giclais , 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}
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