Marine environmental research最新文献

{"title":"Phytoplankton responses to reduced freshwater inflow and acid conditions in a Ramsar estuarine lake","authors":"Chuene P. Lakane ,&nbsp;Janine B. Adams ,&nbsp;Daniel A. Lemley","doi":"10.1016/j.marenvres.2025.107043","DOIUrl":"10.1016/j.marenvres.2025.107043","url":null,"abstract":"<div><div>Global change pressures influence estuarine functionality, driving structural shifts that threaten ecosystem resilience. Estuarine lakes are inherently susceptible to these pressures given their tendency to experience prolonged periods of water residency and mouth closure. As such, this study aimed to investigate water quality and phytoplankton responses to drastic shifts in abiotic conditions during the transition from a dry to wet cycle in the Verlorenvlei Estuarine Lake, South Africa. Initially, drought- and human-induced hydrological constraints resulted in extreme environmental conditions, characterised by low water levels and acidification. These low water levels reduced connectivity, resulting in hypersaline conditions and phytoplankton blooms (&gt;20 μg Chl-<em>a</em> L⁻¹) in the lower reaches, while the main basin became brackish, highly acidic (pH &lt; 4), and ammonium-rich (&gt;10 mg/L). Conversely, increased flow improved connectivity, although the lower reaches remained hypersaline and pH in the main basin remained low. When the mouth was open, conditions became homogenous and oligohaline, with neutralised pH levels (&gt;6.5) and low phytoplankton biomass (&lt;5 μg Chl-<em>a</em> L⁻¹). Upon mouth closure, the lower reaches shifted to mesohaline conditions, the main basin became acidic (pH &lt; 5) and supported high-biomass (&gt;60 μg Chl-<em>a</em> l⁻¹) bloom conditions of non-siliceous taxa, and the upper reaches became disconnected. As such, it is critical for catchment-scale interventions to be implemented that conserve and restore freshwater inflow to dilute acidity and replenish the buffering capacity of the system. Without intervention, ongoing anthropogenic and climate change stressors may push the system towards an irreversible ecological tipping point.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107043"},"PeriodicalIF":3.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biodiversity monitoring in remote marine environments: Advancing environmental DNA/RNA sampling workflows","authors":"Michelle Scriver ,&nbsp;Anastasija Zaiko ,&nbsp;Xavier Pochon ,&nbsp;Jo-Ann L. Stanton ,&nbsp;Olga Belonovich ,&nbsp;Gert-Jan Jeunen ,&nbsp;Austen C. Thomas ,&nbsp;Neil J. Gemmell ,&nbsp;Ulla von Ammon","doi":"10.1016/j.marenvres.2025.107041","DOIUrl":"10.1016/j.marenvres.2025.107041","url":null,"abstract":"<div><div>Understanding biodiversity is crucial for protecting unique environments, but acquiring this knowledge is challenging in isolated areas due to limited availability of easy-to-implement biomonitoring tools. To determine optimal sampling strategies in remote regions, environmental DNA and RNA (eDNA and eRNA) sampling workflows were evaluated at 12 sites in three fiords within Fiordland National Park, Aotearoa-New Zealand. For filtration comparison, a modified cruising speed net was used to concentrate eDNA/eRNA onto 20 μm nylon filters, while water from the net's cod-end was filtered through a 5 μm Smith-Root self-preserving filter using the eDNA Citizen Scientist Sampler. To compare preservation methods, Smith-Root filters were cut in half, with one half preserved in the self-preserving unit and the other in DNA/RNA Shield™ buffer. Biodiversity screening was performed by sequencing the 18S rRNA gene for eukaryotes and two mitochondrial 16S rRNA genes for fish and marine vertebrates. Comparable amplicon sequence variant (ASVs) richness was observed between methods, yet samples preserved with buffer showed higher richness of fish and marine vertebrate taxa and higher PCR amplification success. There was little variation in community composition, except for 16S rRNA targeting fish, where distinct patterns emerged based on preservation methods. Overall, sampling workflows showed similar community composition and alpha diversity across both nucleic acids. These results confirm that enhancing eDNA/eRNA yields for sparse taxa requires consideration of collection and preservation methods. However, abundant taxa biodiversity is captured consistently, allowing for adjustments without compromising robustness. These insights support streamlined eDNA/eRNA sampling, emphasizing adaptive strategies based on targeted taxa.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107041"},"PeriodicalIF":3.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143547934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Ulva prolifera fragment size on the biomass of developing green algae","authors":"Jing Ma ,&nbsp;Qing Dong ,&nbsp;Shiyan Li ,&nbsp;Houxu Ding ,&nbsp;Zhouyue Lu ,&nbsp;Yuxin Xie ,&nbsp;Kangxin Yong ,&nbsp;Juntian Xu","doi":"10.1016/j.marenvres.2025.107037","DOIUrl":"10.1016/j.marenvres.2025.107037","url":null,"abstract":"<div><div>Green tides are on the rise in the world's ocean recently, and Ulva is one of the most important genera to develop this marine disaster. However, the rapid biomass accumulation of this genus is quite complex, so in this study we utilized the different sizes of <em>U. prolifera</em> fragments (0.015, 0.03, 0.05, 0.075, 0.1, 0.2, 0.5, 1, and 2 mm) to explore the relationship between fragment size and green algae biomass. Compared with the relative growth rate (RGR) of the smallest algal fragment size (0.015 mm), the RGR and yield were increased by 25.41% and 0.10%, respectively, for 2-mm algal fragments. The J, I and P phases of the rapid induction curve of chlorophyll fluorescence (OJIP curve) increased significantly in the biggest fragment compared to the smallest algal fragment size. The chlorophyll (Chl) <em>a</em> and <em>b</em> contents in the biggest algal fragment size increased by 46.68% and 41.36%, respectively, compared with the smallest algal fragment size. The Chl <em>a/b</em> ratio also increased significantly in the biggest fragment. Thus, multiple factors can produce algal fragments of varying sizes in <em>U. prolifera</em>, resulting in rapid proliferation under natural conditions. This is among the important factors contributing to the rapid accumulation of <em>U</em>. <em>prolifera</em> biomass.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107037"},"PeriodicalIF":3.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying priority habitat for future spatial conservation and management decisions of East Asian finless porpoise within Miaodao Archipelago waters, China","authors":"Yongtao Li ,&nbsp;Zhongxun Wu ,&nbsp;Yongzhong Chu ,&nbsp;Zhaolong Cheng ,&nbsp;Tao Zuo ,&nbsp;Mingxiang Niu ,&nbsp;Jun Wang","doi":"10.1016/j.marenvres.2025.107040","DOIUrl":"10.1016/j.marenvres.2025.107040","url":null,"abstract":"<div><div>In the realm of marine biodiversity conservation, understanding the dynamics between species' spatial distributions, habitat utilization, and human impacts is crucial. This knowledge is indispensable for marine spatial planning, facilitating the identification and mitigation of conflicts between human activities and the conservation goals of marine ecosystems. The East Asian finless porpoise (<em>Neophocaena asiaeorientalis sunameri</em>), classified as endangered by the IUCN Red List, is the only cetacean routinely observed in the vicinity of the Miaodao Archipelago. To identify key areas for this species and assess the impact of human activities, boat-based surveys were conducted from 2019 to 2023, covering 6220 km² of the Miaodao Archipelago's waters. These surveys recorded 1610 porpoise sightings over 75 survey days. Spatial analysis revealed that the East Asian finless porpoises primarily frequent three core density areas characterized by high sighting densities. Additionally, intermediate density and habitat range areas were delineated, which are essential for the porpoises' movement between these core regions. The study also analyzed the spatial usage of porpoises within and outside areas affected by human activities, revealing that sighting densities were significantly higher in regions with minimal human impact (p &lt; 0.01). Based on these findings, it is proposed that the areas with high porpoise sighting densities be managed as a unified protected area network. These findings should guide future conservation and management strategies within the National Park to ensure the effective preservation of this endangered species.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107040"},"PeriodicalIF":3.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple environmental factors drive the functional dimension of fish communities in the Central East China Sea","authors":"Pengzhan Zhang ,&nbsp;Yang Liu ,&nbsp;Yang Yan ,&nbsp;Linlong Wang ,&nbsp;Yefu Kong ,&nbsp;Xin Peng ,&nbsp;Bin Kang","doi":"10.1016/j.marenvres.2025.107039","DOIUrl":"10.1016/j.marenvres.2025.107039","url":null,"abstract":"<div><div>A study of fish functional diversity based on trait–environment relationships offers new insights into comprehending the community structure of fish within marine ecosystems. The East China Sea is one of the most productive marine regions in China, and its fish communities are facing multiple pressures, including environmental changes, human activities, and habitat degradation. This study aims to investigate the functional <em>α</em>- and <em>β</em>-diversity of fish in the region, identify the environmental factors driving these variations, and explore how fish functional traits respond to these factors, using fish survey data from the central part of the Sea in 2016 and 2020, three functional <em>α</em>-diversity indices (functional richness, functional evenness, and functional divergence) and three functional <em>β</em>-diversity indices (functional <em>β</em>-diversity, functional turnover, and functional nestedness) were determined, as well as their comparisons. Random forest models were adopted to explore the influence of environmental factors on fish functional diversity, and RLQ (a combined analysis of environmental variables table R, species occurrence table L, and functional traits table Q) combined with the fourth-corner method was used to detect correlations between fish functional traits and environmental factors. Compared with 2016, functional richness significantly decreased in 2020, whereas functional divergence significantly increased. Functional <em>β</em>-diversity and functional turnover showed an increasing tendency from 2016 to 2020, and functional turnover and functional nestedness exhibited similar contributions to functional <em>β</em>-diversity across both periods. Chlorophyll <em>a</em> and sea surface temperature were the most influential variables, positively to functional divergence, functional <em>β</em>-diversity, and functional turnover but negatively to functional richness. Traits benthic water column preference and sedentary preference were closely related to lower values of Chlorophyll <em>a</em>, sea surface temperature, and pH. Under the current dramatic environmental changes, sedentary and benthic species were likely to be more vulnerable to exterior disturbances, which highlighted the need to incorporate sedentary and benthic fish into coastal management and conservation strategies.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107039"},"PeriodicalIF":3.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plastic litter is rapidly bioeroded in mangrove forests","authors":"Levy D. Obonaga ,&nbsp;Alejandra Ortiz ,&nbsp;Thomas Wilke ,&nbsp;José M. Riascos","doi":"10.1016/j.marenvres.2025.107027","DOIUrl":"10.1016/j.marenvres.2025.107027","url":null,"abstract":"<div><div>Due to their architectural and hydrodynamic properties, mangrove forests are emerging as global hotspots for plastic sequestration. Mangroves encroached by coastal cities contain up to two orders of magnitude more plastic than their non-urban counterparts. In urban mangroves, plastic substrata are often used as microhabitats, but the consequences of this interaction for the degradation process of plastics in the environment are unknown. Hence, we hypothesized that plastics are differentially colonized and transformed by distinct macrobenthic assemblages in urban vs. wild mangrove forests. To test this hypothesis, plastic sheets (low-density polyethylene, LDPE; polypropylene, PP; polyethylene terephthalate, PET and expanded polystyrene, EPS) were placed in two positions (on-ground and above ground), and the colonizing biota assessed after four months in urban and wild mangrove forests in the southern Colombian Caribbean. We found 19 plant and animal taxa scraping, burrowing into, biting, fracturing, etching, and boring through plastic sheets, demonstrating that bioerosion is a critical degradation pathway that influence the fate of plastic litter in the environment. As hypothesized, there were significant differences in the structure of macrobenthic biota and functional groups of bioeroders between urban and wild forests. Moreover, the bioerosion rate of EPS and PP was faster in urban than in wild mangrove forests. These findings challenge the view that the biological transformation of plastics is a slow process, mainly driven by microorganisms.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"207 ","pages":"Article 107027"},"PeriodicalIF":3.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology, phylogeny, and toxicity of three Gambierdiscus species from the South China Sea, including a coral-killing bloom of G. carpenteri in reef tanks","authors":"Zhaohe Luo ,&nbsp;Xiangyuan Lin ,&nbsp;Xiaowan Liu ,&nbsp;Kieng Soon Hii ,&nbsp;Haiyan Li ,&nbsp;Yan Li ,&nbsp;Xinya Xu ,&nbsp;Jiaguang Xiao ,&nbsp;Hala F. Mohamed ,&nbsp;Xinqing Zheng ,&nbsp;Li Zhang ,&nbsp;Po Teen Lim ,&nbsp;Chui Pin Leaw ,&nbsp;Ye Gao","doi":"10.1016/j.marenvres.2025.107031","DOIUrl":"10.1016/j.marenvres.2025.107031","url":null,"abstract":"<div><div><em>Gambierdiscus</em> is a genus of benthic dinoflagellate commonly found in coral reef ecosystems. Some species produce neurotoxins, such as ciguatoxins (CTXs) and maitotoxins (MTXs), which have been linked to ciguatera poisoning (CP), an illness prevalent in tropical regions. In this study, three <em>Gambierdiscus</em> species, <em>G. caribaeus</em>, <em>G. carpenteri</em>, and <em>G. vietnamensis</em> were identified from coral reefs of the South China Sea based on detailed morphological and phylogenetic analyses. This is the first report of <em>G. carpenteri</em> along the Chinese coast, and a bloom of <em>G</em>. <em>carpenteri</em> in coral culture tank that caused coral mortality was documented. While no known CTXs and MTXs were detected in the newly isolated <em>Gambierdiscus</em> strains, 44-methylgambierone was present in all three species; further, <em>G. carpenteri</em> strains produced protonated adducts of Gambieric acids A and C. The results of MTT in vitro assay showed that <em>G. vietnamensis</em> exhibited the highest cytotoxicity to both cancerous and noncancerous cell lines, while <em>G. caribaeus</em> demonstrated moderate inhibition of noncancerous cells and colon adenocarcinoma, with lower toxicity against other colon cancer cell lines. In contrast, the bloom samples of <em>G. carpenteri</em> showed low cytotoxicity across all tested cell lines, suggesting that <em>G. carpenteri</em> may affect coral health through mechanisms beyond cytotoxicity. Higher nitrogen levels relative to phosphorus likely promoted the initiation of <em>G. carpenteri</em> blooms and sustained the high density in the culture tanks. The shading effect by the massive <em>G. carpenteri</em> mats likely limited the light intensity required by the corals, while elevated NH₄⁺-N concentrations during the bloom period may further contribute to coral mortality. These findings underscore the effects of <em>Gambierdiscus</em> species influencing coral health, highlighting the need for further investigation into the mechanisms underlying the impacts on the reef ecosystems.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107031"},"PeriodicalIF":3.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical distributions of dimethyl sulfide and dimethylsulfoniopropionate and impacts of DMSP lyase and bacteria in the Yellow Sea and East China Sea","authors":"Xin-Ran Song ,&nbsp;Qian-Yao Ma ,&nbsp;Juan Yu ,&nbsp;Gui-Peng Yang ,&nbsp;Rong Chen ,&nbsp;Zheng-Yu Zhang ,&nbsp;Yu Jiang ,&nbsp;Long-Fei Liu","doi":"10.1016/j.marenvres.2025.107036","DOIUrl":"10.1016/j.marenvres.2025.107036","url":null,"abstract":"<div><div>Dimethyl sulfide (DMS), a degradation product of dimethylsulfoniopropionate (DMSP), is a significant trace gas influencing global temperature. This study examined the distribution of DMSP lyase activity (DLA) and the degradation of DMSP and dimethyl sulfoxide (DMSO) by bacteria to elucidate the influences of DMSP lyase and bacteria on the distributions of DMS and DMSP in the Yellow Sea and the East China Sea during the summer. We observed that DMS and DMSP concentrations in transect B, located near the Yellow Sea Cold Water Mass, declined with deepening water depth, coinciding with the changing trend of the temperatures. A positive correlation between Chl <em>a</em> and dissolved and particulate dimethylsulfoniopropionate (DMSP_d,p) concentrations in transects B, D, F, P, and T indicated that DMSP_d,p primarily originated from phytoplankton. The phytoplankton in transects D, F, and P thrived under the nutrient-rich conditions brought by the Yangtze Diluted Water. A positive correlation between DMS concentrations and DMSP_d,p concentrations was found, suggesting that DMS originated from the degradation of DMSP_d,p. Additionally, we successfully isolated twenty-one DMSP-degrading bacteria and twelve DMSO-degrading bacteria capable of utilizing DMSP or DMSO as their sole carbon and sulfur sources. DMSP was consumed by DMSP-degrading bacteria, which simultaneously transformed it into DMS. The DMS production pathway accounted for 2.5%–47.1% of the total DMSP degradation process. Furthermore, the addition of glucose enhanced DMSO degradation by DMSO-degrading bacteria by a factor of 4.5–7.0 compared to conditions without glucose. These findings advance our understanding of the key factors influencing DMS and DMSP dynamics, as well as the roles of DMSP lyase and bacteria in the organic sulfur cycle.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107036"},"PeriodicalIF":3.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitric oxide involved in alleviating iron-deficiency stress in macroalga Gracilariopsis lemaneiformis","authors":"Mingyue Li,&nbsp;Luke Chu,&nbsp;Mo Zou,&nbsp;Lizhen Rong,&nbsp;Nianjun Xu,&nbsp;Xue Sun","doi":"10.1016/j.marenvres.2025.107032","DOIUrl":"10.1016/j.marenvres.2025.107032","url":null,"abstract":"<div><div>Nitric oxide (NO), an active signaling molecule, plays multifaceted roles in plant growth, development, and responses to biotic/abiotic stresses such as high temperature and nutrient deficiency. In marine environments, algae frequently encounter challenges due to limitations in the availability of essential nutrients, including nitrogen, phosphate and iron. Here, sodium nitroprusside (SNP), a NO donor, was employed to investigate the regulating roles of NO on the physiological traits and metabolic pathways in the iron-deficient macroalga <em>Gracilariopsis lemaneiformis</em>. The supply of SNP mitigated the adverse effect due to iron deficiency by promoting the actual photosynthetic efficiency and photochemical quenching coefficient, NO accumulation, proline content, and ferric chelate reductase (FCR) activity, while reducing the malondialdehyde level, thereby alleviating the algal growth inhibition. After a comparative transcriptome analysis, a total of 1255 upregulated- and 3266 downregulated-unigenes were identified in the SNP-supplied alga relative to the iron-deficient <em>G. lemaneiformis</em>. Furthermore, multiple metabolic pathways were significantly enriched, including photosynthesis, carbon metabolism, phenylpropanoid biosynthesis, nitrogen metabolism, glutathione metabolism, and abscisic acid synthesis and signaling pathway, and the latter three were further demonstrated from the enzyme and metabolite levels. In summary, this study will not only present novel insights into how marine macroalgae adapt to iron-limited environments, but also provide a basis for understanding the crucial role and underlying mechanisms of NO mitigating iron-deficiency adversity in <em>G</em>. <em>lemaneiformis</em>.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107032"},"PeriodicalIF":3.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contrasting effects of temperature rise in different seasons on larger and smaller phytoplankton assemblages in a temperate coastal water, Laoshan Bay, northern Yellow Sea, China","authors":"Wei Zhao ,&nbsp;Jihua Liu ,&nbsp;Tingting Li ,&nbsp;Hui Song ,&nbsp;Bokun Chen ,&nbsp;Bingzhang Chen ,&nbsp;Gang Li","doi":"10.1016/j.marenvres.2025.107034","DOIUrl":"10.1016/j.marenvres.2025.107034","url":null,"abstract":"<div><div>Anthropogenic influences and climate change are leading to more frequent and intense heatwaves, which are known to affect marine ecosystems. However, the effects of rising temperatures on <em>in-situ</em> phytoplankton size classes have not yet been adequately studied. In this study, two cell-sized phytoplankton assemblages (&gt;20 μm, &lt;20 μm) were cultured at a range of temperatures [i.e., ambient temperature (AT), AT+3 °C, AT+6 °C and AT+9 °C] in Laoshan Bay, Yellow Sea, China, at half-month intervals between June 2022 and July 2023. Total chlorophyll <em>a</em> concentration fluctuated between 0.84 and 7.76 μg L⁻¹ throughout the year, with the highest value presented in winter with the lowest proportion of smaller cells. Photosynthetic efficiency (F_V/F_M) of larger cells, which varied between 0.15 in winter and 0.52 in summer, was 22% higher than their smaller counterparts, while their growth rate (μ, −0.21 to 0.91 d⁻¹) was 60% higher. The slope derived from the linear fit of F_V/F_M or μ to temperature, an indicator of temperature sensitivity, was positive in winter but negative in summer, depending mainly on ambient temperature. The μ of larger cells was increased more than that of smaller cells by an increase in temperature in winter, but inhibited more in summer, indicating their greater sensitivity to temperature. Our results also showed that the integrated inhibition of a 1 °C temperature increase over one year is 5.45% and 3.68% on the growth of larger and smaller cells, respectively, suggesting a negative effect of temperature increase on phytoplankton community in Laoshan Bay.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"206 ","pages":"Article 107034"},"PeriodicalIF":3.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}