Deep-sea Research Part Ii-topical Studies in Oceanography最新文献

{"title":"Spatial variability in plankton metabolic balance in the tropical Indian Ocean during spring intermonsoon","authors":"V.V.S.S. Sarma ,&nbsp;M.H.K. Prasad ,&nbsp;C.K. Sherin ,&nbsp;K.R. Mangalaa","doi":"10.1016/j.dsr2.2023.105342","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105342","url":null,"abstract":"<div><p><span><span>The tropical Indian Ocean consists of three basins, namely the Arabian Sea (AS), Bay of Bengal (BoB) and Southern Indian Ocean (SIO), with relatively nutrient-rich waters in the former two basins. It is hypothesized that the excess carbon produced in the northern Indian Ocean may support heterotrophic carbon demand in the SIO. In order to test this hypothesis, deck incubation experiments were conducted during the spring intermonsoon under the aegis of the Indian-GEOTRACES program. Nutrients in the mixed layer were low in the SIO compared to AS and BoB due to strong thermal stratification in the former region. Dominant net </span>autotrophy<span> was noticed in the AS whereas net heterotrophy<span><span> in the BoB and SIO. High community respiration (CR) was observed in the BoB which may be supported by riverine organic carbon, whereas in situ produced and advected excess carbon from the northern Indian Ocean may support in AS and SIO respectively. Net community production (NCP) displayed an inverse (linear) relationship with temperature (salinity) in the </span>euphotic zone<span> in the BoB and SIO suggesting that stratification driven by river discharge and equatorial currents, respectively, reduced nutrients inputs through vertical mixing in the upper ocean resulting in the formation of the strong net heterotrophy and contrast to this was found in the AS due to increase in primary production due to nitrogen fixation. The euphotic zone integrated nutrients displayed a linear relationship with NCP and Gross Primary Production (GPP) indicating that the availability of nutrients controlled the plankton metabolic rates in the tropical Indian Ocean. The threshold of GPP for plankton metabolic balance in the tropical Indian Ocean (1.9 mmol O</span></span></span></span>₂ m⁻³ d⁻¹) was close to that of the global mean (2.2 mmol O₂ m⁻³ d⁻¹). The slope of the log-log relationship between GPP and CR was 0.5 and it is close to that of the global mean value of 0.60.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105342"},"PeriodicalIF":3.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92033257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced marine technologies for ocean research","authors":"Allison Miller,&nbsp;Jyotika I. Virmani","doi":"10.1016/j.dsr2.2023.105340","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105340","url":null,"abstract":"<div><p>Technology is fundamental to understanding our ocean and has been used to conduct oceanographic research for over a century. We are in an age of fast innovation and technical advancements that are pushing the boundaries of marine research, exploration, data collection, and telecommunications at sea. Through this, scientists are gaining the ability to collect data at reduced costs, more efficiently, for longer durations, and on scales previously beyond human reach. As a consequence, our knowledge of the ocean is rapidly evolving and, along with that, our capacity to excite broader public interest and inform the better stewardship of our planet.</p><p>This review provides examples of (1) successful technologies that have been used in oceanographic research, many aboard R/V <em>Falkor</em>; (2) prototypes that have the potential to be used more extensively; and (3) innovations in other fields that have not yet been adapted for use in the ocean. This is not an exhaustive review of existing marine technologies that fit these criteria, but collectively, they are increasing the pace of oceanographic discovery and research.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105340"},"PeriodicalIF":3.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0967064523000905/pdfft?md5=1a4b31d27d557e06af3643e54a471a66&pid=1-s2.0-S0967064523000905-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92122347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone","authors":"V. Hemsley ,&nbsp;J. Füssel ,&nbsp;M.T. Duret ,&nbsp;R.R. Rayne ,&nbsp;M.H. Iversen ,&nbsp;S.A. Henson ,&nbsp;R. Sanders ,&nbsp;P. Lam ,&nbsp;M. Trimmer","doi":"10.1016/j.dsr2.2023.105339","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105339","url":null,"abstract":"<div><p>The sinking of photosynthetically produced organic carbon from the ocean surface to its interior is a significant term in the global carbon cycle. Most sinking organic carbon is, however, remineralized in the mesopelagic zone (∼100 m–1000 m), thereby exerting control over ocean-atmosphere carbon dioxide (CO₂) partitioning and hence global climate. Sinking particles are considered hotspots of microbial respiration in the dark ocean. However, our observations in the contrasting Scotia Sea and the Benguela Current show that &gt;90% of microbial remineralisation is associated with suspended, rather than sinking, organic matter, resulting in rapid turnover of the suspended carbon pool and demonstrating its central role in mesopelagic carbon cycling. A non-steady-state model indicates that temporally variable particle fluxes, particle injection pumps and local chemoautotrophy are necessary to help balance the observed mesopelagic respiration. Temperature and oxygen exert control over microbial respiration, particularly for the suspended fraction, further demonstrating the susceptibility of microbial remineralisation to the ongoing decline in oxygen at mid-ocean depths. These observations suggest a partial decoupling of carbon cycling between non-sinking and fast-sinking organic matter, challenging our understanding of how oceanic biological processes regulate climate.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105339"},"PeriodicalIF":3.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50175406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ocean-atmosphere heat exchange seasonal cycle on the West Florida Shelf derived from long term moored data","authors":"Luis Sorinas,&nbsp;Robert H. Weisberg,&nbsp;Yonggang Liu,&nbsp;Jason Law","doi":"10.1016/j.dsr2.2023.105341","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105341","url":null,"abstract":"<div><p>Twenty-three years of surface meteorological and oceanographic data sampled from moored buoys are used to study the seasonal and interannual variations of ocean–atmosphere heat exchange and its influence on West Florida Continental Shelf (WFS) water temperature and stratification. The data are from the University of South Florida's Coastal Ocean Monitoring and Prediction System (COMPS), part of the Southeast Coastal Ocean Observing Regional Association (SECOORA). Observed are incoming short and longwave radiation, air and sea surface temperatures (AT and SST), barometric pressure, relative humidity, wind velocity, water column velocity profiles, and water column temperature at discrete depths. These data are used to estimate net shortwave and longwave radiation and sensible and latent heat fluxes via the COARE 3.6 algorithm. When combined, these radiative and turbulent heat flux influences are compared with the heating and cooling of the WFS water column and SST. On seasonal average, heating starts in February and lasts through August, with a maximum rate of change in May, while cooling starts in September and lasts through January, with the maximum rate of change in October. Also on seasonal average, SST varies from 18.4 °C in February to 30.4 °C in August at mooring C10 (at the 25 m isobath) and from 20.1 °C in February to 30.2 °C in August at mooring C12 (at the 50 m isobath), the differences in the seasonal range being due to increased ocean circulation influence in deeper water. Both the spring and fall transition onsets, February and August, respectively, occur when the sign of the net heat flux changes. The water column begins to stratify in March, peaking in June–July and lagging the surface heating by one or two months, then decreasing through September at C10 and October at C12. Stratification is also modified by persistent upwelling when the Gulf of Mexico Loop Current (LC) interacts with the WFS slope at its southwest corner near the Dry Tortugas. Interannual temperature anomalies from the seasonal cycle are also related to how the LC interacts with the WFS slope.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105341"},"PeriodicalIF":3.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50175404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of tidal mixing on diurnal and intraseasonal air-sea interactions in the Maritime Continent","authors":"John Steffen ,&nbsp;Hyodae Seo ,&nbsp;Carol Anne Clayson ,&nbsp;Suyang Pei ,&nbsp;Toshiaki Shinoda","doi":"10.1016/j.dsr2.2023.105343","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105343","url":null,"abstract":"<div><p>The Maritime Continent (MC) is a region with enhanced tidal mixing and ocean cooling, which influences regional-scale sea surface temperatures (SSTs). We examine the coupled impacts of tidal mixing on near-surface stratification, SST, and deep convection on diurnal and intraseasonal time-scales, using ensembles of high-resolution, coupled ocean-atmosphere regional model simulations, with and without tidal forcing. Results show that the area-averaged SST in the eastern MC is reduced by 0.20 °C due to tidal forcing, with cooling exceeding 1 °C in the nearshore zones of shallow and complex bathymetry. The reduced SSTs decrease surface heat fluxes, leading to tropospheric drying and reduced precipitation, which are most pronounced in the nearshore zones. The results show that the magnitude of tidally-induced SST cooling is phase-dependent during the passage of the Madden Julian Oscillation (MJO). Strong westerly winds enhance entrainment cooling through wind-driven mixing and upwelling during the active phase. Conversely, the upper-ocean stratification is enhanced during the suppressed phase, and SSTs are less sensitive to subsurface cooling. Such spatio-temporal variability in the SST response to tides is accompanied by consistent changes to deep convection and atmospheric circulation. On the diurnal time-scale, nearshore cooling weakens the early-morning convection when the land-based convection propagates offshore and interacts with the cooler SST. On intraseasonal time-scales, the coupling between SST and precipitation is strengthened because of the asymmetric impacts of tide-induced mixing on SST and MJO-induced winds. The robust SST and precipitation responses demonstrated in this study suggest the need for an accurate representation of tidal forcing and vertical mixing processes in local MJO prediction models for the MC.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105343"},"PeriodicalIF":3.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50175408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrodynamic response to bathymetric changes in Tampa Bay, Florida","authors":"Jing Chen ,&nbsp;Yonggang Liu ,&nbsp;Robert H. Weisberg ,&nbsp;Steven A. Murawski ,&nbsp;Sherryl Gilbert ,&nbsp;David F. Naar ,&nbsp;Lianyuan Zheng ,&nbsp;Matthew Hommeyer ,&nbsp;Catherine Dietrick ,&nbsp;Mark E. Luther ,&nbsp;Cheryl Hapke ,&nbsp;Edward Myers ,&nbsp;Saeed Moghimi ,&nbsp;Corey Allen ,&nbsp;Liujuan Tang ,&nbsp;Bahram Khazaei ,&nbsp;Shachak Pe'eri ,&nbsp;Ping Wang","doi":"10.1016/j.dsr2.2023.105344","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105344","url":null,"abstract":"<div><p><span><span>Bathymetric changes within estuarine and coastal waters can alter the hydrodynamic evolution of sea level and currents, which in turn can influence the ecosystem by altering material property distributions. Here we apply the Tampa Bay Coastal Ocean Model (TBCOM), with an unstructured, high-resolution grid to investigate the hydrodynamic response to bathymetric changes at the periphery of the Tampa Bay mouth over a relatively small area when compared to the whole model domain. Two separate numerical experiments are conducted with the same forcing, one using the original bathymetry and the other employing a revised synthetic bathymetry. The simulated sea level, amplitude and phase of the M2 tide, and associated currents are compared for the two experiments. Significant changes in water level (up to+/-10 cm) and </span>current velocities (up to 20 cm/s) are found in the shallow peripheral area with the two different bathymetric data sets. These bathymetric influences are not limited to the locations where the bathymetric changes occur; they also extend to remote areas of the bay. Since Tampa Bay bathymetry varies with storm-induced sediment redistributions and human actives such as shipping channel </span>dredging<span> and beach nourishment, these findings emphasize the need for accurate and updated bathymetry for coastal ocean modeling and applications.</span></p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105344"},"PeriodicalIF":3.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92033258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Export of Dissolved Organic Carbon (DOC) compared to the particulate and active fluxes near South Georgia, Southern Ocean","authors":"Elisa Lovecchio ,&nbsp;Louis Clément ,&nbsp;Claire Evans ,&nbsp;Rachel Rayne ,&nbsp;Cynthia Dumousseaud ,&nbsp;Saeed Roshan ,&nbsp;Sarah L.C. Giering ,&nbsp;Adrian Martin","doi":"10.1016/j.dsr2.2023.105338","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105338","url":null,"abstract":"<div><p>Quantifying the relative contributions of the export of particulate organic carbon (POC), dissolved organic carbon (DOC) and active fluxes by migrating organisms is essential to understand the functioning and vulnerability of the ocean's biological pump. However, these fluxes are rarely measured at the same time. Here we provide a first simultaneous comparison of these biological pump components in the region of South Georgia. We use a combination of in-situ data and an inverse model to calculate the DOC export and the suspended POC export and compare them to the sinking POC and active export. We find that, in this region, the DOC total export contributes about 6.6% (23.0–37.5 mg C m⁻² day⁻¹) to the total export flux, the active flux has no discernible contribution, and the sinking POC flux is dominant with a mean value of 409 mg C m⁻² day⁻¹. Diapycnal fluxes of DOC obtained from the cruise data constitute only a minor fraction (0.05–1.28 mg C m⁻² day⁻¹) of the total DOC export estimated by the inverse model and are exceeded on average by the diapycnal flux of suspended POC. Our results also indicate that the total export of DOC is driven by isopycnal transport. Future fieldwork in the region of South Georgia should focus on quantifying the isopycnal flux of DOC. Future measurement campaigns should also aim to simultaneously measure the particulate, dissolved and active components of the biological pump at contrasting locations and at different times to resolve the variability of their relative contribution.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"212 ","pages":"Article 105338"},"PeriodicalIF":3.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50175405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal variability of eddy kinetic energy in the Banda Sea revealed by an ocean model: An energy budget perspective","authors":"Zhanjiu Hao ,&nbsp;Zhenhua Xu ,&nbsp;Ming Feng ,&nbsp;Peiwen Zhang ,&nbsp;Jia You ,&nbsp;Baoshu Yin","doi":"10.1016/j.dsr2.2023.105320","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105320","url":null,"abstract":"<div><p>Seasonal eddy kinetic energy (EKE) variability in the Banda Sea during 1993–2014 is studied from an energy budget perspective, based on the outputs of Ocean Forecasting Australian Model version 3. High EKE is confined within the upper 300 m of the western Banda Sea with the largest intensity exceeding 3 <span><math><mrow><mo>×</mo></mrow></math></span> 10³ J/m²<span><span> in the northwest monsoon (NWM) season. In this strong EKE region during NWM, eddies derive almost two thirds of their kinetic energy from the direct wind power input (WP), with additional contributions from the barotropic (BT) and baroclinic instability (BC) of the background flow. Both WP and BT modulate the EKE </span>seasonality<span> and drive the peak energy during NWM, while BC strengthens in the southeast monsoon (SEM) season because of the intensified baroclinicity of the upper circulation. The westerly wind bursts associated with the Madden-Julian Oscillation (MJO), together with steep topography, facilitate more cyclonic eddy generation events in the western Banda Sea during NWM. During SEM, EKE becomes relatively moderate across the Banda Sea but with a regional peak to the southwest of the Buru Island, which can be attributed to island wake effect. Over the Banda Sea, WP, BT and BC contribute 74% (42%), 14% (19%) and 12% (39%) of total energy to EKE during NWM (SEM), respectively. The majority of EKE generated is diverged horizontally by pressure work and dissipated by turbulent viscosity, with dissipation depleting the most. This study highlights the importance of both monsoon and MJO wind forcing in generating EKE variability along the pathway of the Indonesian Throughflow.</span></span></p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"211 ","pages":"Article 105320"},"PeriodicalIF":3.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50177398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A data-assimilative modeling investigation of Gulf Stream variability","authors":"Shun Mao ,&nbsp;Ruoying He ,&nbsp;John Bane ,&nbsp;Glen Gawarkiewicz ,&nbsp;Robert E. Todd","doi":"10.1016/j.dsr2.2023.105319","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105319","url":null,"abstract":"<div><p>An advanced data-assimilative ocean circulation model is used to investigate Gulf Stream<span><span><span><span> (GS) variability during 2017–2018. The modeling system applies a strong-constraint, 4D variational data assimilation<span> algorithm. It assimilates satellite-based sea surface height and </span></span>sea surface temperature measurements and in situ temperature and </span>salinity profiles. Model skill assessment metrics along with comparisons of GS position and GS's three-dimensional mean kinetic energy with historical observations are applied to validate the data-assimilative model. The resulting time- and space-continuous ocean state estimates are used to diagnose eddy kinetic energy conversion and cross-stream eddy heat and salt fluxes over the two-year study period. The processes leading to kinetic energy conversion are primarily due to GS meanders. Significant inverse energy cascading (EKE→MKE and EKE→EPE) can occur during GS-eddy interactions, particularly during onshore intrusions or offshore meanderings of the GS. Throughout the two-year study period, the cross-stream eddy heat and salt fluxes off Cape Hatteras were predominantly positive (onshore). Both GS offshore meandering (occurring 44% of the time and associated with shelf/slope water export) and GS intrusion (occurring 56% of the time) contribute to onshore heat and salt transport. Improved understanding of these processes and dynamics requires strong integration of an advanced observational infrastructure that combines </span>remote sensing; fixed, mobile, and shore-based observing components; and high-resolution data assimilative models.</span></p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"211 ","pages":"Article 105319"},"PeriodicalIF":3.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50177399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monsoonal variation and its impact on the feeding habit of Bali Sardinella (S. lemuru Bleeker, 1853) in Bali Strait","authors":"A. Sartimbul ,&nbsp;H. Nakata ,&nbsp;E.Y. Herawati ,&nbsp;E. Rohadi ,&nbsp;D. Yona ,&nbsp;L.I. Harlyan ,&nbsp;A.D.R. Putri ,&nbsp;V.A. Winata ,&nbsp;R.I. Khasanah ,&nbsp;Z. Arifin ,&nbsp;R.D. Susanto ,&nbsp;F.M. Lauro","doi":"10.1016/j.dsr2.2023.105317","DOIUrl":"https://doi.org/10.1016/j.dsr2.2023.105317","url":null,"abstract":"<div><p><em>Sardinella lemuru</em><span> is known as a highly opportunistic and flexible forager. Their high abundance in the coastal upwelling of Bali Strait was initially attributed to their feeding habit on phytoplankton and hence attaining higher catch. It was challenged by subsequent reports which suggested zooplankton as their main diet. This difference is due to the lack of information on the one-year cycle of its seasonal feeding. Here we used a combination of the plankton in seawater and the stomach contents of </span><em>S. lemuru</em><span> and monsoonal oceanographic changes at Bali Strait to determine the diet composition and food selectivity in four fishing seasons of 2012–2013. The result shows that </span><em>S. lemuru</em> is an omnivorous fish, and its diet composition depends on plankton availability in the environment, size classes, and the monsoonal oceanographic change influenced by upwelling. This condition strongly supported high nutrients for phytoplankton availability in the seawater with medium diversity and moderate community stability, except in inter-monsoon-2 (Trans-2). Phytoplankton was found as the main diet item of <em>S. lemuru</em> during the higher abundance of phytoplankton (82.26% <span><em>Rhizosolenia</em><em> stolterfothii</em></span>) in Trans-2. In contrast, its main diet was substituted by zooplankton (51.96% <span><em>Nauplius</em><em> of Paraeuchaeta norvegica</em></span>) during lower phytoplankton abundance in the northwest monsoon (NW). In addition, <em>S. lemuru</em><span> has adaptive strategies in feeding habits: It not only has flexibility but also selectivity in the feeding habit, supported by the ability to perform vertical migration for plankton grazing in different depths, move to another feeding ground, or plankton might be carried by the Indonesian Throughflow (ITF) into the Bali Strait. This study provides valuable information on the feeding ecology of </span><em>S. lemuru</em>, possibly providing a scientific basis for the proper management of <em>the S. lemuru</em> fishery in Bali Strait.</p></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"211 ","pages":"Article 105317"},"PeriodicalIF":3.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50177396","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}