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

{"title":"Uncovering the hidden amphipod biodiversity and its drivers in the Persian Gulf","authors":"Farzaneh Momtazi ,&nbsp;Abdolvahab Maghsoudlou ,&nbsp;Hanieh Saeedi","doi":"10.1016/j.dsr2.2025.105463","DOIUrl":"10.1016/j.dsr2.2025.105463","url":null,"abstract":"<div><div>The Persian Gulf (PG), an epicontinental sea at the northwestern corner of the Indian Ocean presents a challenging environment in which species confront the upper limits of their environmental tolerance. Previous hypotheses suggested that the PG is a homogeneous ecosystem characterized by low species diversity and a limited number of endemic species. We investigated these hypotheses by studying the amphipods' distribution pattern and environmental drivers, a dominant benthic group in the PG. We compiled an extensive database of amphipod distribution by integrating the open-access data including the Ocean Biodiversity Information System (OBIS) and Global Biodiversity Information Facility (GBIF), literature mining on amphipods, as well as the author's sampling database from the Persian Gulf and the Gulf of Oman. Following careful data cleaning and quality control, the final dataset comprised 1411 distribution records of 134 accepted marine amphipod species collected from depths ranging from 0 to 100 m. The environmental variables were extracted from the Bio-ORACLE database for the benthic layer with the maximum depth. Species richness per hexagonal cells (alpha species richness), and ES15 (expected number of species per 15 random samples) were calculated. Our findings revealed higher-than-expected species richness and non-homogeneous amphipod distribution across the region. Two biodiversity hotspots were identified in the northern and northwestern parts of the PG and a lowspot of amphipod species diversity in the southern half. Beta diversity cluster analysis exhibited three distinct compositions of amphipod assemblages: a northwestern community near the Arvand (Shat AL-Arab) river, a northern assemblage along Iranian coasts and the Strait of Hormuz region, and a southern assemblage along Arabian coasts. Generalized Additive Models (GAMs) and General Linear Models (GLMs) outputs showed that all environmental variables, pH, and temperature were the most important drivers in delimiting the benthic species distributions and richness. Our findings emphasize the need for a detailed approach to understanding the distribution and diversity of marine organisms in the PG where data and knowledge are less shared openly. This region should not be treated as a homogeneous ecosystem, as it harbors many endemic and rare species threatened by anthropogenic activities such as oil extraction and ocean warming.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105463"},"PeriodicalIF":2.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421546","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":"Diet of deep-sea octocorals from the Emperor Seamount Chain inferred by fatty acid trophic markers","authors":"S.A. Rodkina,&nbsp;T.N. Dautova","doi":"10.1016/j.dsr2.2025.105462","DOIUrl":"10.1016/j.dsr2.2025.105462","url":null,"abstract":"<div><div>Despite the important role that octocorals (Cnidaria: Octocorallia) play in creating and maintaining deep-sea communities known as coral gardens, little is known about their diet. We analyzed the fatty acid compositions of deep-sea octocorals collected from Koko Guyot, located in the southern Emperor Seamount Chain, to identify their main food sources. The data suggests that octocorals feed mainly on zooplankton. However, the contribution of zooplankton to their diet varies greatly among different species and is determined by different zooplankton groups (herbivores, carnivores, or omnivores). This is evidenced by the increased content of some monounsaturated fatty acids (FA) and the different ratios of polyunsaturated fatty acids in corals. In bamboo coral <em>Isidella</em>, we observed the maximum enrichment in calanoid copepod markers (20:1n-9 and 22:1n-1). In addition to the copepod markers, most corals showed a high level of the carnivore marker (18:1n-9), which indicates a significant contribution of other (non-calanoid copepods) items to the diet. The high level of n-3 polyunsaturated fatty acids (PUFA) such as the diatom marker 20:5n-3 suggests that corals of the family Primnoidae take up more freshly produced material. However, the high level of n-6 PUFA (especially, 20:4n-6), found in Paramuriceidae and <em>Keroeides</em> corals may indicate the involvement of detrital links in their diet. FA analysis is useful for identifying the diet of cold-water octocorals and provides a basis for prediction of future potential changes of the bottom ecosystems in the Emperor Seamount Chain.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105462"},"PeriodicalIF":2.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395369","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":"Brought to the surface from obscurity: The distribution and biology of Coelorhinchus gilberti (Macrouridae, Gadiformes, Teleostei) off the Emperor Seamounts (Northwestern Pacific)","authors":"Nikolai B. Korostelev ,&nbsp;Igor V. Volvenko ,&nbsp;Igor V. Maltsev ,&nbsp;Alexei M. Orlov","doi":"10.1016/j.dsr2.2025.105461","DOIUrl":"10.1016/j.dsr2.2025.105461","url":null,"abstract":"<div><div><em>Coelorinchus gilberti</em> is a member of the grenadier family (Macrouridae) found off the Pacific coast of Japan (from Shikoku Island to Hokkaido Island), the Kyushu-Palau submarine ridge, and the Emperor Seamounts. This species is a common bycatch in the longline fishery for the skilfish <em>Erilepis zonifer</em> (Anoplopomatidae) and some rockfishes (Sebastidae). However, there is no published information on its distribution and biology. Based on observations on commercial longlines between 2014 and 2018, the catch distribution, size and sex, size of otoliths, age and growth, sex ratio and sexual maturity of <em>C. gilberti</em> in the waters of the Emperor Seamounts (NW Pacific) are presented. This species has been caught from Nintoku Seamount in the north to Kammu Seamount in the south and is most commonly found off the Jingu, Ojin, and Kammu seamounts. The species has been recorded from 215 to 1840 m, which significantly extends its known bathymetric range. The catches included individuals from 34 to 93 cm (mean 53.2 cm), weight 140–5240 g (mean 688.2 g) and age from 24 to 48 years (mean 37.9 years). The females were significantly longer, heavier and older than the males and generally dominated the catches (the proportion of males &lt;40%). The growth of <em>C. gilberti</em> is best described by a von Bertalanffy growth function (VBGF), and the parameters of the von Bertalanffy growth equation were L∞ = 61.6, k = 0.09, t₀ = −1.4. Spawning individuals were recorded in catches only in April, which is the end of spawning. Further research with year-round trawl samples is needed to obtain more detailed information on the life cycle of <em>C. gilberti</em>.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105461"},"PeriodicalIF":2.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386454","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":"Estimating quantitative gear and taxa specific encounter thresholds for commercial fisheries bycatch of vulnerable marine ecosystem indicator taxa","authors":"Christopher N. Rooper ,&nbsp;Kayleigh Somers ,&nbsp;Pamela Goddard ,&nbsp;Glenn Campbell","doi":"10.1016/j.dsr2.2024.105448","DOIUrl":"10.1016/j.dsr2.2024.105448","url":null,"abstract":"<div><div>Corals and sponges are often a component of vulnerable marine ecosystems (VMEs) in the deep sea. These taxa can be impacted and removed by bottom contacting fishing gear and protecting VMEs is an important component of managing ecosystems. One of the tools that is routinely used to manage VME impacts from fishing gear is move-on rules triggered by bycatch thresholds (encounter thresholds) of VME. Usually, these bycatch thresholds are set with little information regarding the level of impact on the benthic habitat. The objective of this analysis was to develop and apply methods for quantifying threshold catches of VME indicator taxa by gear type and VME indicator taxa grouping. Three previously used methods based on cumulative bycatch distributions and one novel method based on percentile regression of fishery bycatch and density from underwater camera surveys were applied to data from the northeast Pacific Ocean to determine data-based encounter thresholds that could trigger spatial fishery closures. The percentile regression method suggested encounter thresholds of ∼40–65 kg of Antipatharia, &lt;20 kg of gorgonians and 78–131 kg of Porifera would equate to a density of 0.2 VME indicator taxa per <span><math><mrow><msup><mi>m</mi><mn>2</mn></msup></mrow></math></span> for bottom trawl bycatch. Threshold values were lower for longline and pot gear (generally &lt;10 kg per set). Using the percentile regression method allowed for the definition of VME encounter thresholds to be expressed in terms of density of the taxa of interest, an improvement over examination of break points in the cumulative bycatch data alone. This improvement allows the ecological importance (e.g. density of VME) to be defined and used to estimate encounter thresholds, rather than assuming that the natural break points in cumulative bycatch represent an ecological break point.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105448"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161548","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":"The seasonal patterns of hydrographic and biogeochemical variables in the Ross Sea: A BGC-Argo analysis","authors":"Ruobing Cao ,&nbsp;Walker O. Smith Jr. ,&nbsp;Yisen Zhong ,&nbsp;Stephen Riser ,&nbsp;Kenneth S. Johnson ,&nbsp;Lynne Talley","doi":"10.1016/j.dsr2.2024.105436","DOIUrl":"10.1016/j.dsr2.2024.105436","url":null,"abstract":"<div><div>Seasonal patterns in seasonally frozen waters have usually been derived from composites of analyses conducted in different years and largely have been confined to ice-free periods. We present the first continuous measurements of hydrographic and biogeochemical variables collected over an entire year by Biogeochemical-Argo (BGC-Argo) profiling floats on the continental shelf of the Ross Sea. Analyses were divided into two periods: autumn/winter and spring/summer. Mixed layers increased rapidly upon ice cover, and nitrate, oxygen, and dissolved inorganic carbon vertical distributions were strongly influenced by this deeper mixing. Rates of nitrification in autumn were substantial and similar to rates measured in other areas of the ocean. Organic carbon disappearance was also most rapid in March. Changes in all variables slowed considerably after May. The largest mixed layer depths occurred at the southern floats and reached 400–500 m. Spring/summer patterns were similar to those observed during individual cruises, with rapid nitrate removal beginning in November, continuing through early January, but ceasing during austral summer. The most rapid accumulations of chlorophyll occurred prior to complete ice retreat. Substantial spatial differences were noted that were likely related to both mixed layer depths and phytoplankton composition. Particulate matter accumulated throughout the summer below 100 m, although the rates of change suggested substantial remineralization in the water column. The temporal patterns observed show the importance of relatively short periods that markedly influence the vertical distribution of biogeochemical parameters.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105436"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161545","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":"The relative contribution of deep and shallow benthic sources to iron supply in the Ross sea, with specific emphasis on Ross Bank","authors":"Blair J.W. Greenan ,&nbsp;Michael S. Dinniman ,&nbsp;Dennis J. McGillicuddy Jr. ,&nbsp;Peter N. Sedwick ,&nbsp;Stefanie L. Mack ,&nbsp;Walker O. Smith Jr.","doi":"10.1016/j.dsr2.2024.105450","DOIUrl":"10.1016/j.dsr2.2024.105450","url":null,"abstract":"<div><div>Summer primary productivity in the Ross Sea is limited by the availability of dissolved iron (DFe) in the euphotic zone. Previous studies have suggested that benthic sources dominate the supply of DFe to the upper water column in the southern Ross Sea polynya. The purpose of this study is to investigate whether these benthic sources are derived from shallow banks or deeper areas of the continental shelf. Our study combines analysis of <em>in situ</em> observations near Ross Bank with a physical ocean model simulation in an overlapping summertime period to investigate the vertical supply of DFe. Two passive tracer dyes were employed in the ocean model with the first (second) being input in the bottom model layer over seabed depths of less (greater) than 400 m. The tracer dyes provide temporal (March 2011–January 2012) and spatial estimates of the advection, mixing and diffusion throughout the Ross Sea model domain, and enable estimates of the relative contributions of shallow and deep benthic iron sources to the upper ocean DFe inventory. A comparison of the model output with a ship-based survey and a mooring deployed on Ross Bank in January 2012 provides confidence that the model simulations produce a sufficiently accurate representation of ocean conditions to support estimates of benthic DFe supply to surface waters. The results demonstrate that for Ross Bank the local (on-bank) benthic supply is important during the early winter period, whereas for most of the year the deep (off-bank) benthic iron is the predominant source supplying the upper ocean over this shallow region.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105450"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161547","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":"Progression of marine heat wave events over the tropical Indian Ocean and its underlying mechanisms","authors":"Diya Das ,&nbsp;Sachiko Mohanty","doi":"10.1016/j.dsr2.2024.105438","DOIUrl":"10.1016/j.dsr2.2024.105438","url":null,"abstract":"<div><div>Marine Heat Waves (MHW) are devastating extreme oceanic events that have severe and destructive effects on the marine and coastal ecosystems. In the present study, the generation and advancement of MHW events during the last four decades over the tropical Indian Ocean (IO) and its primary regulating factors are investigated. Multiple MHW events have been detected over the tropical IO in the past decade. It was found that between 2011 and 2021, the tropical Indian Ocean observed a significant increase in both the mean annual number of MHW days and the frequency of MHW occurrences. This coincided with a substantial rise in sea surface temperatures (SST) in the region during the same period. Long-running events were detected for the years 2015 over the Somali coast, 2016 over the Java-Sumatra Coast, and for 2019, and 2020 over the Seychelles Dome. Event-specific analysis revealed that a decline in wind speed was observed during the second phase of the 2015 MHW event along the Somali coast which resulted in the subsidence of upwelling, similar observations were also made around the Java-Sumatra coast. Subsequently, the role of planetary waves in the sustenance of the long-running MHW events is analysed. Positive sea level anomaly values were observed around Somali and Sumatra for 2015 and 2016, which in turn signify the presence of downwelling planetary waves. These planetary waves play an important role in oceanic surface and sub-surface warming and mixing by deepening thermocline and consequentially inhibiting the upwelling and entrainment. An analysis of the mixed layer heat budget terms over the active regions of MHW events in 2015, 2016, 2019, and 2020 shows that the primary contributor influencing these MHW events is net heat flux over the majority of the affected areas which is followed by the dominant role of vertical advection over the Somali region.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105438"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161062","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":"Biogeochemistry of the Ross Sea and its ecosystem implication","authors":"Paola Rivaro,&nbsp;Carmela Ianni","doi":"10.1016/j.dsr2.2024.105449","DOIUrl":"10.1016/j.dsr2.2024.105449","url":null,"abstract":"<div><div>The Ross Sea is one of the best-sampled Antarctic continental shelves and represents an important region for biogeochemistry with respect to the ocean circulation and the global climate regulation. It is a key site for production of Antarctic Bottom Water (AABW) and supports the largest primary productivity in the Southern Ocean. Moreover, it plays a fundamental role in the air–sea carbon dioxide (CO₂) flux, behaving as an atmospheric CO₂ sink. Some of the most important features of the main chemical variables (nutrients, iron, carbonate system variables) are summarized, considering both recent advances in our understanding and the implications of their variability for the biogeochemistry of the Ross Sea. New observations will provide an opportunity to better understand the complex interactions that regulate the biogeochemical cycles of elements in the Ross Sea and their change in the near future.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105449"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161544","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":"Fine-scale variability in habitat selection and niche differentiation between sponges and cold-water corals on vertical walls of the Charlie-Gibbs Fracture Zone","authors":"Ana Belén Yánez-Suárez ,&nbsp;Loïc Van Audenhaege ,&nbsp;Tyler D. Eddy ,&nbsp;Katleen Robert","doi":"10.1016/j.dsr2.2024.105437","DOIUrl":"10.1016/j.dsr2.2024.105437","url":null,"abstract":"<div><div>Deep-sea vertical walls are characterized by enhanced hydrodynamics and hard substrates, making them particularly suitable habitats for suspension feeders, including vulnerable marine ecosystems (VMEs) indicator taxa, like cold-water corals (CWC) and sponges. These species enhance the complexity of the abiotic background and the retention of trophic resources increasing habitat availability for other organisms. While some areas of vertical walls present a high density of VMEs, others are mostly bare rock. However, the habitat characteristics that favor the presence of CWC and sponges within vertical walls at a fine-scale (under 1 m) are still poorly understood despite their ecological importance. Owing to technological limitations, fine-scale terrain variables (e.g., orientation, curvature, verticality, roughness, slope) have seldom been quantified in deep-sea habitats. These terrain variables can represent proxies of community structuring factors (e.g., hydrodynamics conveying food, sedimentation rates) important to understand habitat selection of VME indicator species. In this study, we investigate the fine-scale habitat selection and niche differentiation of CWC and sponges on vertical walls of the Charlie-Gibbs Fracture Zone. Structure-from-motion photogrammetry was employed to create high-resolution 3D models of three vertical walls based on remotely operated vehicle (ROV) videos (at 1060-1901 m depth). The 3D models were used to derive terrain variables at fine-scale and geotag corals and sponges. Using ecological niche factor analysis, we reveal that corals and sponges selected habitat features that significantly differ from the average habitat available. The corals and sponges studied showed large or complete niche partitioning. <em>Solenosmilia</em> sp. had total niche separation with <em>Geodia</em> spp. and globular sponges and partial separation with <em>Hertwigia</em> spp., while Scleralcyonacea showed partial niche separation with <em>Geodia</em> spp. and globular sponges. Conversely, the niches of closely related sponges were more similar. This research advances our understanding of the processes enabling species co-existence among these organisms and the factors influencing habitat preferences of VME indicator species on steep underwater landscapes.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105437"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161061","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":"Contrasting trends of the ocean CO2 sink and pH in the agulhas current system and the Mozambique basin, south-western Indian ocean (1963–2023)","authors":"Nicolas Metzl ,&nbsp;Claire Lo Monaco ,&nbsp;Guillaume Barut ,&nbsp;Jean-François Ternon","doi":"10.1016/j.dsr2.2025.105459","DOIUrl":"10.1016/j.dsr2.2025.105459","url":null,"abstract":"<div><div>We describe new observations of the oceanic carbonate system in the South-Western Indian Ocean obtained in January 2021 (OISO-31 cruise) and May 2022 (RESILIENCE cruise). To evaluate the decadal trends and drivers of fugacity of CO₂ (fCO₂), air-sea CO₂ fluxes, dissolved inorganic carbon (C_T) and pH, we used available data in this region over 1963–2023 and compared the results in the Mozambique Basin and in the Agulhas region near the African coast. Over 1995–2023, we found a faster fCO₂ increase in the Mozambique basin (2.03 ± 0.07 μatm.yr⁻¹) compared to the coastal zone (1.37 ± 0.07 μatm.yr⁻¹). The temporal change of anthropogenic CO₂ concentrations estimated in subsurface enables to reconstruct the carbonate system properties since the 1960s. In the Mozambique Basin the CO₂ sink increased slightly over 1960–2022 with a maximum observed in May 2022 (−2.4 mmolC.m⁻².d⁻¹). In the coastal zone, the ocean CO₂ sink increased from near equilibrium in the 1960s to a maximum observed in May 2022 (−4.2 mmolC.m⁻².d⁻¹). In both regions, we found a decrease of pH, most pronounced in the open ocean zone (−0.020 ± 0.001.decade⁻¹ over 1995–2023). The lowest pH of 8.04 was observed in January 2021, 0.11 lower than in the 1960s. The increase of the CO₂ sink and the decrease of pH were mainly driven by anthropogenic CO₂ uptake, with about 10% due to the ocean warming.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105459"},"PeriodicalIF":2.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104383","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}