Pub Date : 2024-07-31DOI: 10.1016/j.jmarsys.2024.104000
Gustavo A. Thompson , Graciela N. Molinari , Martin D. Ehrlich , Maria C. Daponte
The complex distribution of gelatinous zooplankton at the shelf and open ocean of the Southwestern Atlantic Ocean (31°-38°S) was closely linked to the prevailing water masses. Species composition differed significantly between subtropical and subantarctic assemblages in both neritic and oceanic environments. Diversity was lower in neritic and Malvinas assemblages but higher to the north of the Brazil-Malvinas Confluence. The influence of the Brazil Current was evident through the dominance of warm-water species such as Flaccisagitta enflata, Fl. hexaptera, Pterosagitta draco, Pseudosagitta lyra, and Salpa fusiformis, which displayed the highest abundances and different maturity stages north of the Confluence. The cold-waters originating from subantarctic regions were indicated by the presence of Ps. gazellae, Eukrhonia hamata, and Serratosagitta tasmanica, which showed higher abundances and the co-occurrence of different maturity stages south of the Confluence. The spread of low-salinity water into oceanic stations was indicated by the presence of species such as Parasagitta friderici and Pa. tenuis, which are typically found in neritic waters with low salinity. The coexistence of typical species from both warm- and cold-waters at oceanic stations in the Confluence section reflects the complex oceanographic structure of one of the most intense open-ocean fronts in the world ocean.
{"title":"Distribution, abundance, and reproductive stages of salps, doliolids, and chaetognaths in different water masses of the shelf and open ocean of the Southwestern Atlantic Ocean between 31° and 38° S","authors":"Gustavo A. Thompson , Graciela N. Molinari , Martin D. Ehrlich , Maria C. Daponte","doi":"10.1016/j.jmarsys.2024.104000","DOIUrl":"10.1016/j.jmarsys.2024.104000","url":null,"abstract":"<div><p>The complex distribution of gelatinous zooplankton at the shelf and open ocean of the Southwestern Atlantic Ocean (31°-38°S) was closely linked to the prevailing water masses. Species composition differed significantly between subtropical and subantarctic assemblages in both neritic and oceanic environments. Diversity was lower in neritic and Malvinas assemblages but higher to the north of the Brazil-Malvinas Confluence. The influence of the Brazil Current was evident through the dominance of warm-water species such as <em>Flaccisagitta enflata, Fl. hexaptera, Pterosagitta draco, Pseudosagitta lyra</em>, and <em>Salpa fusiformis</em>, which displayed the highest abundances and different maturity stages north of the Confluence. The cold-waters originating from subantarctic regions were indicated by the presence of <em>Ps. gazellae, Eukrhonia hamata,</em> and <em>Serratosagitta tasmanica</em>, which showed higher abundances and the co-occurrence of different maturity stages south of the Confluence. The spread of low-salinity water into oceanic stations was indicated by the presence of species such as <em>Parasagitta friderici</em> and <em>Pa. tenuis</em>, which are typically found in neritic waters with low salinity. The coexistence of typical species from both warm- and cold-waters at oceanic stations in the Confluence section reflects the complex oceanographic structure of one of the most intense open-ocean fronts in the world ocean.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"246 ","pages":"Article 104000"},"PeriodicalIF":2.7,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945117","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 : 2024-06-24DOI: 10.1016/j.jmarsys.2024.103999
Lucas de la Maza , Evie A. Wieters , Ricardo Beldade , Mauricio F. Landaeta , Alejandro Perez-Matus , Sergio A. Navarrete
<div><p>Oceans have been changing at the fastest pace since the beginning of the Holocene. The South Eastern Pacific (SEP), including the Humboldt Upwelling Ecosystem (HUE) is subject to changes in upwelling winds, temperature, El Niño, and the ever-increasing local anthropogenic stressors, all of which have been documented for surface coastal waters where in-situ and remote observations are readily available. Temporal and spatial changes in the adjacent deeper waters where diverse Mesophotic Ecosystems are found have been scarcely documented. These marine ecosystems have been the focus of ecological studies for less than two decades. Here we provide an overview of the thermal variability at mesophotic depths and assess their potential as climatic refugia along all SEP ecoregions. We analyzed a time series of temperature and salinity from a 19 yr reanalysis based on remote and in-situ observations (CTD, ARGO, XBTs, moorings) to quantify variability in the Tropical (0–5°S), Northern Warm Temperate (5–30°S); Southern Warm Temperate (30–39.5°S) and Magellanic subregions (39.5–45°S), at two mesophotic depth strata (50 and 100 m), and a reference surface (5 m) depth. We assessed variability in the seasonal, interannual (El Niño) and ‘long-term’ (ca. 20 yr) scales, and the relationship with wind velocities. The thermal depth gradient between surface and mesophotic depths did not change smoothly with latitude but peaked within the northern portion of the warm temperate subregion, decreasing towards lower and higher latitudes. Seasonal variation in temperature was also largest in the north and south temperate subregions and minimal in the Magellanic subregion. Depth dampening of seasonal temperature variation was also strengthened at intermediate latitudes and much reduced in the tropics, where seasonal variation at mesophotic depths was similar to that at the surface. The strong interannual El Niño events were identified at all depths in tropical and temperate subregions, with stronger standardized effects at mesophotic layers than at the surface. Long-term (ca. two decades) temperature trends were significant and changed direction from warming to cooling along the SEP but were generally patchier at mesophotic layers. Spatial temperature gradients have remained relatively stable over the past two decades and were stronger at the surface than at mesophotic depths, and stronger within the tropics than in all other subregions. Surprisingly, the velocity of climate change was patchier and generally faster at mesophotic layers than at the surface. We conclude that, judging solely by physical environmental conditions, mesophotic ecosystems may be used by species with very different temperature affinities in temperate subregions, while in the tropics, more overlap in temperature affinities of component species may be found. Importantly, while the seasonal amplitude is reduced at mesophotic depth in most subregions, except the tropics, interannual disturbances
{"title":"Variability in oceanographic conditions affecting Mesophotic Ecosystems along the South Eastern Pacific: Latitudinal trends and potential for climate refugia","authors":"Lucas de la Maza , Evie A. Wieters , Ricardo Beldade , Mauricio F. Landaeta , Alejandro Perez-Matus , Sergio A. Navarrete","doi":"10.1016/j.jmarsys.2024.103999","DOIUrl":"https://doi.org/10.1016/j.jmarsys.2024.103999","url":null,"abstract":"<div><p>Oceans have been changing at the fastest pace since the beginning of the Holocene. The South Eastern Pacific (SEP), including the Humboldt Upwelling Ecosystem (HUE) is subject to changes in upwelling winds, temperature, El Niño, and the ever-increasing local anthropogenic stressors, all of which have been documented for surface coastal waters where in-situ and remote observations are readily available. Temporal and spatial changes in the adjacent deeper waters where diverse Mesophotic Ecosystems are found have been scarcely documented. These marine ecosystems have been the focus of ecological studies for less than two decades. Here we provide an overview of the thermal variability at mesophotic depths and assess their potential as climatic refugia along all SEP ecoregions. We analyzed a time series of temperature and salinity from a 19 yr reanalysis based on remote and in-situ observations (CTD, ARGO, XBTs, moorings) to quantify variability in the Tropical (0–5°S), Northern Warm Temperate (5–30°S); Southern Warm Temperate (30–39.5°S) and Magellanic subregions (39.5–45°S), at two mesophotic depth strata (50 and 100 m), and a reference surface (5 m) depth. We assessed variability in the seasonal, interannual (El Niño) and ‘long-term’ (ca. 20 yr) scales, and the relationship with wind velocities. The thermal depth gradient between surface and mesophotic depths did not change smoothly with latitude but peaked within the northern portion of the warm temperate subregion, decreasing towards lower and higher latitudes. Seasonal variation in temperature was also largest in the north and south temperate subregions and minimal in the Magellanic subregion. Depth dampening of seasonal temperature variation was also strengthened at intermediate latitudes and much reduced in the tropics, where seasonal variation at mesophotic depths was similar to that at the surface. The strong interannual El Niño events were identified at all depths in tropical and temperate subregions, with stronger standardized effects at mesophotic layers than at the surface. Long-term (ca. two decades) temperature trends were significant and changed direction from warming to cooling along the SEP but were generally patchier at mesophotic layers. Spatial temperature gradients have remained relatively stable over the past two decades and were stronger at the surface than at mesophotic depths, and stronger within the tropics than in all other subregions. Surprisingly, the velocity of climate change was patchier and generally faster at mesophotic layers than at the surface. We conclude that, judging solely by physical environmental conditions, mesophotic ecosystems may be used by species with very different temperature affinities in temperate subregions, while in the tropics, more overlap in temperature affinities of component species may be found. Importantly, while the seasonal amplitude is reduced at mesophotic depth in most subregions, except the tropics, interannual disturbances ","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103999"},"PeriodicalIF":2.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141542341","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}
Euphausiids (or “krill”) play a crucial role in the food webs of eastern boundary upwelling systems. Their inter-specific predatory interactions with ecologically and commercially important species highlights the importance of understanding krill variability at different temporal and spatial scales. In the Humboldt Current System (HCS), few studies have addressed the spatio-temporal variability of krill communities and their link with climate and local environmental drivers. We studied the patterns and variability of euphausiid diversity in the coastal area off northern Chile, using zooplankton and CTD-O data, and satellite environmental data from the falls and springs of 2010–2017. The community showed low diversity and evenness, with the endemic species Euphausia mucronata being the most abundant. The environmental variance showed 2 main modes of variability: (1) upwelling-associated changes in the depth of the oxygen minimum zone (OMZ) and in temperature, and (2) interannual variability in salinity, associated with ENSO-driven water-mass changes. The diversity indices and community structure showed large fluctuations in the cross-shore direction, and with latitude. The general pattern showed higher diversity offshore and southward, with few species in the low temperature, shallow OMZ conditions of the coastal band. During the 2013 and 2016 marine heatwaves and the 2015-2016 El Niño, the Subtropical Water Mass was advected southward, causing an increase in salinity and temperature, and a decrease in total krill abundance. However, ENSO variability did not significantly affect the species composition. The changes in community structure were caused by fluctuations in species abundance rather than species presence, as the most abundant species dominated the community throughout the study period. These results indicate that the krill communities of the HCS are highly resilient to climate perturbations, with upwelling-associated gradients being the primary source of variability for euphausiid populations in this ecosystem.
{"title":"Mesoscale and climate environmental variability drive krill community changes in the Humboldt Current System","authors":"Macarena Díaz-Astudillo , Ramiro Riquelme-Bugueño , Gonzalo S. Saldías , Jaime Letelier","doi":"10.1016/j.jmarsys.2024.103998","DOIUrl":"10.1016/j.jmarsys.2024.103998","url":null,"abstract":"<div><p>Euphausiids (or “krill”) play a crucial role in the food webs of eastern boundary upwelling systems. Their inter-specific predatory interactions with ecologically and commercially important species highlights the importance of understanding krill variability at different temporal and spatial scales. In the Humboldt Current System (HCS), few studies have addressed the spatio-temporal variability of krill communities and their link with climate and local environmental drivers. We studied the patterns and variability of euphausiid diversity in the coastal area off northern Chile, using zooplankton and CTD-O data, and satellite environmental data from the falls and springs of 2010–2017. The community showed low diversity and evenness, with the endemic species <em>Euphausia mucronata</em> being the most abundant. The environmental variance showed 2 main modes of variability: (1) upwelling-associated changes in the depth of the oxygen minimum zone (OMZ) and in temperature, and (2) interannual variability in salinity, associated with ENSO-driven water-mass changes. The diversity indices and community structure showed large fluctuations in the cross-shore direction, and with latitude. The general pattern showed higher diversity offshore and southward, with few species in the low temperature, shallow OMZ conditions of the coastal band. During the 2013 and 2016 marine heatwaves and the 2015-2016 El Niño, the Subtropical Water Mass was advected southward, causing an increase in salinity and temperature, and a decrease in total krill abundance. However, ENSO variability did not significantly affect the species composition. The changes in community structure were caused by fluctuations in species abundance rather than species presence, as the most abundant species dominated the community throughout the study period. These results indicate that the krill communities of the HCS are highly resilient to climate perturbations, with upwelling-associated gradients being the primary source of variability for euphausiid populations in this ecosystem.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103998"},"PeriodicalIF":2.7,"publicationDate":"2024-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141403269","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 : 2024-06-07DOI: 10.1016/j.jmarsys.2024.103993
Julio Poblete-Ulloa , Marcelo H. Gutiérrez , Carina B. Lange , Diego A. Narváez , Paulina Montero , Humberto E. González , Camila Fernández
A high-resolution survey of distribution, abundance and composition of phytoplankton was carried out for the first time in surface waters of the continental shelf off Chilean Patagonia (41–48°S). An Imaging FlowCytobot was used along the survey track to record phytoplankton in the size range of 10–120 μm during the austral spring of 2018. Phytoplankton community structure was complemented with continuous underway measurements of temperature and salinity, and physicochemical parameters of the water column at 35 oceanographic stations. Our results evidenced two main macrozones with distinctive phytoplankton assemblages delimited latitudinally at ~45°S. The northern macrozone was characterized by higher surface temperature and salinity, Si:N ratio > 1, diatoms of the genera Thalassiosira and Chaetoceros, and dinoflagellates accounting for over 70% of the total abundance. The southern macrozone, with lower surface temperature and salinity and Si:N ratio < 1, was characterized by members of the genera Guinardia, Lauderia and Cerataulina, representing over 60% of the total phytoplankton. These changes were attributable to the strong influence of freshwater at latitudes higher than 45°S and the enhanced discharge of meltwaters from Patagonian icefields in the area of the Taitao Peninsula and the Gulf of Penas (47–-48°S). Fresh and cold waters impacted the water column stratification and the availability of dissolved silicic acid with potential effects on phytoplankton composition and diatom cell silicification and, thus, on carbon exportation. Our estimations of phytoplankton carbon were comparable to those observed in Patagonian fjords and the highly productive upwelling ecosystem of central Chile. We suggest that the continental shelf off Patagonia can contribute significantly to strengthen the biological carbon pump through the synthesis, exportation, and sequestration of phytoplankton-based organic carbon in the southeastern Pacific Ocean.
{"title":"Freshwater discharge drives latitudinal changes of phytoplankton composition on the continental shelf off Chilean Patagonia","authors":"Julio Poblete-Ulloa , Marcelo H. Gutiérrez , Carina B. Lange , Diego A. Narváez , Paulina Montero , Humberto E. González , Camila Fernández","doi":"10.1016/j.jmarsys.2024.103993","DOIUrl":"10.1016/j.jmarsys.2024.103993","url":null,"abstract":"<div><p>A high-resolution survey of distribution, abundance and composition of phytoplankton was carried out for the first time in surface waters of the continental shelf off Chilean Patagonia (41–48°S). An Imaging FlowCytobot was used along the survey track to record phytoplankton in the size range of 10–120 μm during the austral spring of 2018. Phytoplankton community structure was complemented with continuous underway measurements of temperature and salinity, and physicochemical parameters of the water column at 35 oceanographic stations. Our results evidenced two main macrozones with distinctive phytoplankton assemblages delimited latitudinally at ~45°S. The northern macrozone was characterized by higher surface temperature and salinity, Si:N ratio > 1, diatoms of the genera <em>Thalassiosira</em> and <em>Chaetoceros</em>, and dinoflagellates accounting for over 70% of the total abundance. The southern macrozone, with lower surface temperature and salinity and Si:N ratio < 1, was characterized by members of the genera <em>Guinardia</em>, <em>Lauderia</em> and <em>Cerataulina</em>, representing over 60% of the total phytoplankton. These changes were attributable to the strong influence of freshwater at latitudes higher than 45°S and the enhanced discharge of meltwaters from Patagonian icefields in the area of the Taitao Peninsula and the Gulf of Penas (47–-48°S). Fresh and cold waters impacted the water column stratification and the availability of dissolved silicic acid with potential effects on phytoplankton composition and diatom cell silicification and, thus, on carbon exportation. Our estimations of phytoplankton carbon were comparable to those observed in Patagonian fjords and the highly productive upwelling ecosystem of central Chile. We suggest that the continental shelf off Patagonia can contribute significantly to strengthen the biological carbon pump through the synthesis, exportation, and sequestration of phytoplankton-based organic carbon in the southeastern Pacific Ocean.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103993"},"PeriodicalIF":2.8,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141412059","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 : 2024-06-05DOI: 10.1016/j.jmarsys.2024.103997
Lijian Yang , Xiaochuan Ma , Yiwei He , Min Gao , Jie Huang , Jian Lu , Zhendong Luan
The differentiation of sediment grain size from large river deltas to distal areas in a coastal flow system and its evolution are vital because they greatly contribute to matter transport, pollution accumulation, and carbon cycling on the inner shelf. Here, the Yellow River sedimentary system in the adjacent seas is studied, including the proximal delta of the Yellow River and the distal mud patch. The grain size distributions of the suspended particulate matter (SPM), surface sediments, and core sediments in the Shandong Peninsula Coastal Current (SPCC) system were integrated and analyzed. The results show that apparent variations in the grain size distribution exist in the SPM and sediments in the SPCC system. The grain size distribution of the SPM near the proximal delta of the Yellow River is multimodal and variable with water depth, whereas that in the distal mud area is typically unimodal. The coarse-grained endmember of suspended sediments is restricted in the proximal area by ocean fronts under fair weather conditions in both summer and winter and is only transported to the distal mud area under strengthened coastal currents in winter. In contrast, fine-grained endmembers can be transported far away under tidal currents and coastal currents year-round. The temporal grain size variation near the proximal delta is also significantly affected by historical shifts in the Yellow River mouth, while the strength of coastal currents associated with the East Asian Winter Monsoon (EAWM) controls the grain size distribution in the distal mud area. The roles of river behaviors, ocean fronts, tides, and winds are all highlighted in the control of grain size differentiation. These results potentially have significance for understanding sediment dynamics and mass transport processes in similar coastal current systems involving large rivers worldwide.
{"title":"Spatiotemporal variations in the grain size distribution in the water column and sediments from the Yellow River Delta to distal areas under coastal currents","authors":"Lijian Yang , Xiaochuan Ma , Yiwei He , Min Gao , Jie Huang , Jian Lu , Zhendong Luan","doi":"10.1016/j.jmarsys.2024.103997","DOIUrl":"https://doi.org/10.1016/j.jmarsys.2024.103997","url":null,"abstract":"<div><p>The differentiation of sediment grain size from large river deltas to distal areas in a coastal flow system and its evolution are vital because they greatly contribute to matter transport, pollution accumulation, and carbon cycling on the inner shelf. Here, the Yellow River sedimentary system in the adjacent seas is studied, including the proximal delta of the Yellow River and the distal mud patch. The grain size distributions of the suspended particulate matter (SPM), surface sediments, and core sediments in the Shandong Peninsula Coastal Current (SPCC) system were integrated and analyzed. The results show that apparent variations in the grain size distribution exist in the SPM and sediments in the SPCC system. The grain size distribution of the SPM near the proximal delta of the Yellow River is multimodal and variable with water depth, whereas that in the distal mud area is typically unimodal. The coarse-grained endmember of suspended sediments is restricted in the proximal area by ocean fronts under fair weather conditions in both summer and winter and is only transported to the distal mud area under strengthened coastal currents in winter. In contrast, fine-grained endmembers can be transported far away under tidal currents and coastal currents year-round. The temporal grain size variation near the proximal delta is also significantly affected by historical shifts in the Yellow River mouth, while the strength of coastal currents associated with the East Asian Winter Monsoon (EAWM) controls the grain size distribution in the distal mud area. The roles of river behaviors, ocean fronts, tides, and winds are all highlighted in the control of grain size differentiation. These results potentially have significance for understanding sediment dynamics and mass transport processes in similar coastal current systems involving large rivers worldwide.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103997"},"PeriodicalIF":2.8,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141290069","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 : 2024-06-04DOI: 10.1016/j.jmarsys.2024.103996
Amavi N. Silva , Duncan A. Purdie , Nicholas R. Bates , Toby Tyrrell
Deviations of surface ocean dissolved oxygen (O2) from equilibrium with the atmosphere should be rectified about twenty times more quickly than deviations of dissolved carbon dioxide (CO2). Therefore, persistent O2 disequilibria in the Labrador Sea, while CO2 is close to equilibrium, has been a matter of interest to many previous works. Here we investigate this phenomenon by using a novel analytical technique, the ‘CORS (Carbon Dioxide and Oxygen Relative to Saturation) method’, and also by using more data than was available previously. We compare observations to results from a model we developed for the Labrador Sea which combines plankton ecology with biogeochemical cycling of oxygen, carbon and nitrogen. In contrast to earlier works which mostly considered individual factors in isolation, here we used the model, together with data, to distinguish between the varying influences of several processes potentially contributing to the long-lasting O2 undersaturation: mixed layer depth, duration of mixed layer deepening, convection, entrainment and bottom water O2 content. Our model experiments confirm that, for the same gas exchange rate, the effects on surface O2 concentration differ significantly among the identified drivers. Our results suggest that prolonged surface O2 undersaturation is not always dependent on the extreme winter mixed layer depths, but rather that even moderately deep mixed layers (e.g. 300 m), when prolonged and in conjunction with continuous entrainment of oxygen-depleted deep water, can also drive persistent surface O2 anomalies. An implication of our results is that regions in the North Atlantic with maximum winter mixed layer depths of only a few hundred metres should also show persistent surface O2 undersaturation. We further reveal that convection in deep water formation regions produces trendlines that do not pass through the origin of a plot of CO2 vs. O2 deviations which have previously been thought to indicate erroneous data.
{"title":"Investigating Labrador Sea's persistent surface O2 anomaly using observations and biogeochemical model results","authors":"Amavi N. Silva , Duncan A. Purdie , Nicholas R. Bates , Toby Tyrrell","doi":"10.1016/j.jmarsys.2024.103996","DOIUrl":"https://doi.org/10.1016/j.jmarsys.2024.103996","url":null,"abstract":"<div><p>Deviations of surface ocean dissolved oxygen (O<sub>2</sub>) from equilibrium with the atmosphere should be rectified about twenty times more quickly than deviations of dissolved carbon dioxide (CO<sub>2</sub>). Therefore, persistent O<sub>2</sub> disequilibria in the Labrador Sea, while CO<sub>2</sub> is close to equilibrium, has been a matter of interest to many previous works. Here we investigate this phenomenon by using a novel analytical technique, the ‘CORS (Carbon Dioxide and Oxygen Relative to Saturation) method’, and also by using more data than was available previously. We compare observations to results from a model we developed for the Labrador Sea which combines plankton ecology with biogeochemical cycling of oxygen, carbon and nitrogen. In contrast to earlier works which mostly considered individual factors in isolation, here we used the model, together with data, to distinguish between the varying influences of several processes potentially contributing to the long-lasting O<sub>2</sub> undersaturation: mixed layer depth, duration of mixed layer deepening, convection, entrainment and bottom water O<sub>2</sub> content. Our model experiments confirm that, for the same gas exchange rate, the effects on surface O<sub>2</sub> concentration differ significantly among the identified drivers. Our results suggest that prolonged surface O<sub>2</sub> undersaturation is not always dependent on the extreme winter mixed layer depths, but rather that even moderately deep mixed layers (e.g. 300 m), when prolonged and in conjunction with continuous entrainment of oxygen-depleted deep water, can also drive persistent surface O<sub>2</sub> anomalies. An implication of our results is that regions in the North Atlantic with maximum winter mixed layer depths of only a few hundred metres should also show persistent surface O<sub>2</sub> undersaturation. We further reveal that convection in deep water formation regions produces trendlines that do not pass through the origin of a plot of CO<sub>2</sub> vs. O<sub>2</sub> deviations which have previously been thought to indicate erroneous data.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103996"},"PeriodicalIF":2.8,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0924796324000344/pdfft?md5=3ab28f80ed74e5e6bde616b23c18602e&pid=1-s2.0-S0924796324000344-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141303727","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 : 2024-06-01DOI: 10.1016/j.jmarsys.2024.103995
Yang Li , Zhao Xu , Jie Shi , Xiaohui Ma , Jishang Xu
Near-inertial waves (NIWs) play an important role in diapycnal processes and energy dissipation. A mooring observation deployed on the continental shelf in the East China Sea captured anomalously intensified subsurface near-inertial kinetic energy (NIKE) during the passage of Typhoon Danas (2013). An early study has investigated the role of Parametric Subharmonic Instability (PSI) induced by internal tides in the intensification of the subsurface intensified near-inertial velocity. However, results based on regional numerical simulations reveal that strong subsurface near-inertial velocity persists even in the absence of tidal effects, implying the existence of additional sources of NIWs. Our analyses showed that after excluding the effect of PSI, approximately 30% of the remaining subsurface NIKE can be attributed to another Typhoon Fitow (2013), which occurred a week prior to Typhoon Danas. Constrained by the Kuroshio current and the continental shelf, the NIKE generated by Typhoon Fitow propagates northward and reaches the mooring location, leading to the intensified subsurface NIW signal. Our simulation, together with the observations, suggests complicated NIW dynamics in continental shelf regions, involving interactions between successive typhoons, topography and background current, and differing from the open ocean. These interactions will further influence vertical mixing on the continental shelf along the pathway of NIW.
{"title":"A mechanism of enhanced subsurface near-inertial kinetic energy in the East China Sea associated with successive typhoons","authors":"Yang Li , Zhao Xu , Jie Shi , Xiaohui Ma , Jishang Xu","doi":"10.1016/j.jmarsys.2024.103995","DOIUrl":"10.1016/j.jmarsys.2024.103995","url":null,"abstract":"<div><p>Near-inertial waves (NIWs) play an important role in diapycnal processes and energy dissipation. A mooring observation deployed on the continental shelf in the East China Sea captured anomalously intensified subsurface near-inertial kinetic energy (NIKE) during the passage of Typhoon Danas (2013). An early study has investigated the role of Parametric Subharmonic Instability (PSI) induced by internal tides in the intensification of the subsurface intensified near-inertial velocity. However, results based on regional numerical simulations reveal that strong subsurface near-inertial velocity persists even in the absence of tidal effects, implying the existence of additional sources of NIWs. Our analyses showed that after excluding the effect of PSI, approximately 30% of the remaining subsurface NIKE can be attributed to another Typhoon Fitow (2013), which occurred a week prior to Typhoon Danas. Constrained by the Kuroshio current and the continental shelf, the NIKE generated by Typhoon Fitow propagates northward and reaches the mooring location, leading to the intensified subsurface NIW signal. Our simulation, together with the observations, suggests complicated NIW dynamics in continental shelf regions, involving interactions between successive typhoons, topography and background current, and differing from the open ocean. These interactions will further influence vertical mixing on the continental shelf along the pathway of NIW.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103995"},"PeriodicalIF":2.8,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141274258","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 : 2024-06-01DOI: 10.1016/j.jmarsys.2024.103991
M.S. Doldan , P.C. Zaidman , G.N. Williams , L.H. Gimenez , E.M. Morsan
Certain marine regions in the world lack long instrumental records of environmental variables or such records are incomplete. This deficiency particularly applies to Argentine Patagonia, where existing instrumental records span only the last few decades. In the present study it was explored whether such data can be reconstructed from a natural archive, specifically shells of the bivalve mollusk Glycymeris longior from the San Matías Gulf, north Patagonia. For this purpose, a multidecade-long time-series was constructed using variations in the annual shell growth. The time-series spans from 1890 to 2020 and is based on shells from museum collections (live-collected from 1918, 1933 and 1945) and from scientific surveys conducted between 1989 and 2021. An analysis of the links between environmental variables and shell growth was performed between 1976 and 2020 (expressed population signal >0.85). The common signal among the growth curves of individual specimens of G. longior suggests that the growth is influenced by environmental parameters. However, the growth of G. longior did not show significant correlations with the low- nor with the high-frequency components of SST and food supply (chlorophyll-a concentration and POC), suggesting that these parameters do not limit shell growth at the studied site or were undetected with our analyses. The chronology also seems to be insensitive to regional climate patterns such as the Southern Annular Mode. The chronology has the potential for being expanded spatially and temporally.
{"title":"Marine environmental variability in Northern Patagonia (Southwestern Atlantic Ocean) as recorded in Glycymeris longior shells","authors":"M.S. Doldan , P.C. Zaidman , G.N. Williams , L.H. Gimenez , E.M. Morsan","doi":"10.1016/j.jmarsys.2024.103991","DOIUrl":"10.1016/j.jmarsys.2024.103991","url":null,"abstract":"<div><p>Certain marine regions in the world lack long instrumental records of environmental variables or such records are incomplete. This deficiency particularly applies to Argentine Patagonia, where existing instrumental records span only the last few decades. In the present study it was explored whether such data can be reconstructed from a natural archive, specifically shells of the bivalve mollusk <em>Glycymeris longior</em> from the San Matías Gulf, north Patagonia. For this purpose, a multidecade-long time-series was constructed using variations in the annual shell growth. The time-series spans from 1890 to 2020 and is based on shells from museum collections (live-collected from 1918, 1933 and 1945) and from scientific surveys conducted between 1989 and 2021. An analysis of the links between environmental variables and shell growth was performed between 1976 and 2020 (expressed population signal >0.85). The common signal among the growth curves of individual specimens of <em>G. longior</em> suggests that the growth is influenced by environmental parameters. However, the growth of <em>G. longior</em> did not show significant correlations with the low- nor with the high-frequency components of SST and food supply (chlorophyll-a concentration and POC), suggesting that these parameters do not limit shell growth at the studied site or were undetected with our analyses. The chronology also seems to be insensitive to regional climate patterns such as the Southern Annular Mode. The chronology has the potential for being expanded spatially and temporally.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103991"},"PeriodicalIF":2.8,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141278596","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 : 2024-06-01DOI: 10.1016/j.jmarsys.2024.103992
Ilias Semmouri , Jonas Mortelmans , Charlie Roland , Colin R. Janssen , Jana Asselman
Time-series are fundamental for enhancing our comprehension of plankton community dynamics and forecasting future changes that could significantly affect entire marine food chains and ecosystems. In this study, we investigated spatial and temporal variations in occurrence, abundance and body size of marine branchiopods in the Belgian Part of the North Sea (BPNS), using both traditional microscopy, as well as digital imaging (ZooSCAN). We studied the population dynamics of branchiopods collected between 2014 and 2021 in the BPNS and compared these results with a previously collected (2009–2010) dataset for the same area. The time series showed no significant changes in abundance (Podon spp., Evadne nordmanni) over the years, but we did observe a pronounced seasonal pattern, with both species completely absent in the winter months. Abundance and biomass were positively correlated with water temperature but negatively correlated with nutrient concentrations and turbidity. Additionally, Podon spp. abundance was negatively correlated with anthropogenic chemicals (i.e., polycyclic aromatic hydrocarbons). We employed generalized additive models to quantify the relative contribution of temperature, salinity, turbidity, chlorophyll a concentration and pollutant levels to the dynamics of the studied taxa. Turbidity and chlorophyll a concentrations were revealed to be the predictor with the highest importance in all models predicting the abundances/body size of the selected species. Anthropogenic chemicals were not informative in explaining branchiopod abundance or body size. The findings of this study establish a baseline for future studies, which is essential for our understanding of the zooplankton dynamics in the North Sea, particularly in the context of climate change and changing water quality.
时间序列对于提高我们对浮游生物群落动态的理解以及预测可能对整个海洋食物链和生态系统产生重大影响的未来变化至关重要。在这项研究中,我们利用传统显微镜和数字成像(ZooSCAN)技术,调查了北海比利时部分海域(BPNS)海洋枝足类的出现、丰度和体型的时空变化。我们研究了 2014 年至 2021 年期间在比利时北海海域采集的桡足类种群动态,并将这些结果与之前在同一海域采集的数据集(2009-2010 年)进行了比较。时间序列显示,多年来(Podon spp.、Evadne nordmanni)的丰度没有明显变化,但我们确实观察到了明显的季节性模式,这两种生物在冬季完全消失。丰度和生物量与水温呈正相关,但与营养浓度和浑浊度呈负相关。此外,牙鲆的丰度与人为化学物质(即多环芳烃)呈负相关。我们采用广义加法模型来量化温度、盐度、浑浊度、叶绿素 a 浓度和污染物水平对所研究类群动态的相对贡献。浊度和叶绿素 a 浓度在所有预测所选物种丰度/体型的模型中都是最重要的预测因子。人为化学物质对解释枝足类的丰度或体型没有参考价值。这项研究的结果为今后的研究建立了一个基线,这对我们了解北海浮游动物的动态至关重要,尤其是在气候变化和水质变化的背景下。
{"title":"Decadal trends and dynamics in the abundance and biomass of marine branchiopods in the southern part of the North Sea","authors":"Ilias Semmouri , Jonas Mortelmans , Charlie Roland , Colin R. Janssen , Jana Asselman","doi":"10.1016/j.jmarsys.2024.103992","DOIUrl":"https://doi.org/10.1016/j.jmarsys.2024.103992","url":null,"abstract":"<div><p>Time-series are fundamental for enhancing our comprehension of plankton community dynamics and forecasting future changes that could significantly affect entire marine food chains and ecosystems. In this study, we investigated spatial and temporal variations in occurrence, abundance and body size of marine branchiopods in the Belgian Part of the North Sea (BPNS), using both traditional microscopy, as well as digital imaging (ZooSCAN). We studied the population dynamics of branchiopods collected between 2014 and 2021 in the BPNS and compared these results with a previously collected (2009–2010) dataset for the same area. The time series showed no significant changes in abundance (<em>Podon</em> spp., <em>Evadne nordmanni</em>) over the years, but we did observe a pronounced seasonal pattern, with both species completely absent in the winter months. Abundance and biomass were positively correlated with water temperature but negatively correlated with nutrient concentrations and turbidity. Additionally, <em>Podon</em> spp. abundance was negatively correlated with anthropogenic chemicals (i.e., polycyclic aromatic hydrocarbons). We employed generalized additive models to quantify the relative contribution of temperature, salinity, turbidity, chlorophyll <em>a</em> concentration and pollutant levels to the dynamics of the studied taxa. Turbidity and chlorophyll <em>a</em> concentrations were revealed to be the predictor with the highest importance in all models predicting the abundances/body size of the selected species. Anthropogenic chemicals were not informative in explaining branchiopod abundance or body size. The findings of this study establish a baseline for future studies, which is essential for our understanding of the zooplankton dynamics in the North Sea, particularly in the context of climate change and changing water quality.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103992"},"PeriodicalIF":2.8,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141264247","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 : 2024-06-01DOI: 10.1016/j.jmarsys.2024.103994
Lin Yang , Jiayu Chen , Jing Zhang , Gui-Peng Yang , Bin Yang
Carbon monoxide (CO) concentrations in the atmosphere and ocean are mainly influenced by anthropogenic inputs, abiotic photoproduction, biogenic sources, and bacterial consumption. This study, for the first time, investigated the distributions, sea-to-air fluxes, and microbial consumption rates of CO in the Bohai Sea (BS) and the Yellow Sea (YS) in winter to identify the main factors controlling CO distributions in both the atmosphere and seawater in colder temperature. Atmospheric CO mixing ratios ([CO]atm) and the concentrations of CO in surface seawater ([CO]surf) ranged from 176.8 to 1245.8 ppbv (mean value: 551.4 ± 214 ppbv) and from 0.49 to 3.1 nmol L−1 (mean value: 0.98 ± 0.55 nmol L−1), respectively. In addition, the spatial distribution of [CO]atm and [CO]surf showed that anthropogenic sources dominated the distribution of [CO]atm, but abiotic photoproduction processes were the main influencers of the distribution of [CO]surf. The surface water at most sampling stations was supersaturated with CO, with a mean saturation factor of 1.9, and the sea-to-air fluxes of CO were estimated to range from −13.88 to 123.88 nmol m−2 h−1 (12.59 ± 21.32 nmol m−2 h−1), suggesting that the BS and the YS were the source of atmospheric CO, and were estimated to contribute 0.009% to 1.4% to the global ocean emission. Microbial consumption experiments indicated that the microbial CO consumption rate constants (Kbio) ranged from 0.15 to 2.14 h−1, and showed that CO concentrations decreased exponentially with incubation time, suggesting that anaerobic CO consumption would limit CO accumulation in winter, thereby affecting the flux of [CO]surf to [CO]atm.
大气和海洋中的一氧化碳(CO)浓度主要受人为输入、非生物光产、生物源和细菌消耗的影响。本研究首次调查了渤海和黄海冬季一氧化碳的分布、海气通量和微生物消耗率,以确定控制低温条件下大气和海水中一氧化碳分布的主要因素。大气中的 CO 混合比([CO]atm)和表层海水中的 CO 浓度([CO]surface)分别为 176.8 至 1245.8 ppbv(平均值:551.4 ± 214 ppbv)和 0.49 至 3.1 nmol L-1(平均值:0.98 ± 0.55 nmol L-1)。此外,[CO]大气和[CO]海面的空间分布表明,人为来源主导了[CO]大气的分布,但非生物光产生过程是[CO]海面分布的主要影响因素。大多数采样站的表层水CO过饱和,平均饱和系数为1.9,CO的海气通量估计为-13.88至123.88 nmol m-2 h-1(12.59 ± 21.32 nmol m-2 h-1),表明BS和YS是大气CO的来源,估计占全球海洋排放量的0.009%至1.4%。微生物消耗实验表明,微生物 CO 消耗速率常数(Kbio)在 0.15 至 2.14 h-1 之间,并表明 CO 浓度随培养时间呈指数下降,这表明厌氧 CO 消耗将限制冬季 CO 的积累,从而影响 [CO]surf 至 [CO]atm 的通量。
{"title":"Distributions, sea-to-air fluxes, and biological consumption of carbon monoxide in the Bohai and Yellow Seas during winter","authors":"Lin Yang , Jiayu Chen , Jing Zhang , Gui-Peng Yang , Bin Yang","doi":"10.1016/j.jmarsys.2024.103994","DOIUrl":"10.1016/j.jmarsys.2024.103994","url":null,"abstract":"<div><p>Carbon monoxide (CO) concentrations in the atmosphere and ocean are mainly influenced by anthropogenic inputs, abiotic photoproduction, biogenic sources, and bacterial consumption. This study, for the first time, investigated the distributions, sea-to-air fluxes, and microbial consumption rates of CO in the Bohai Sea (BS) and the Yellow Sea (YS) in winter to identify the main factors controlling CO distributions in both the atmosphere and seawater in colder temperature. Atmospheric CO mixing ratios ([CO]<sub>atm</sub>) and the concentrations of CO in surface seawater ([CO]<sub>surf</sub>) ranged from 176.8 to 1245.8 ppbv (mean value: 551.4 ± 214 ppbv) and from 0.49 to 3.1 nmol L<sup>−1</sup> (mean value: 0.98 ± 0.55 nmol L<sup>−1</sup>), respectively. In addition, the spatial distribution of [CO]<sub>atm</sub> and [CO]<sub>surf</sub> showed that anthropogenic sources dominated the distribution of [CO]<sub>atm</sub>, but abiotic photoproduction processes were the main influencers of the distribution of [CO]<sub>surf</sub>. The surface water at most sampling stations was supersaturated with CO, with a mean saturation factor of 1.9, and the sea-to-air fluxes of CO were estimated to range from −13.88 to 123.88 nmol m<sup>−2</sup> h<sup>−1</sup> (12.59 ± 21.32 nmol m<sup>−2</sup> h<sup>−1</sup>), suggesting that the BS and the YS were the source of atmospheric CO, <!--> <!-->and were estimated to contribute 0.009% to 1.4% to the global ocean emission. Microbial consumption experiments indicated that the microbial CO consumption rate constants (<em>K</em><sub>bio</sub>) ranged from 0.15 to 2.14 h<sup>−1</sup>, and showed that CO concentrations decreased exponentially with incubation time, suggesting that anaerobic CO consumption would limit CO accumulation in winter, thereby affecting the flux of [CO]<sub>surf</sub> to [CO]<sub>atm</sub>.</p></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"245 ","pages":"Article 103994"},"PeriodicalIF":2.8,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141281804","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}