{"title":"Pioneers of plankton research: Priscilla Susan Bury (1799–1872)","authors":"John R. Dolan","doi":"10.1093/plankt/fbad051","DOIUrl":"https://doi.org/10.1093/plankt/fbad051","url":null,"abstract":"","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"5 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007717","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}
Laura K Helenius, Erica J H Head, Phoebe Jekielek, Christopher D Orphanides, Pierre Pepin, Geneviève Perrin, Stéphane Plourde, Marc Ringuette, Jeffrey A Runge, Harvey J Walsh, Catherine L Johnson
Copepod size and energy content are influenced by regional and seasonal variation in temperature and food conditions, with implications for planktivorous consumers such as the endangered North Atlantic right whale (Eubalaena glacialis). Historical data (1990–2020) on Calanus finmarchicus stage CV copepodite prosome length and oil sac metrics were analyzed to determine the extent of variation in individual body size and estimated lipid and energy content in five regions of the Northwest Atlantic continental shelves [Gulf of Maine (GoM), Scotian Shelf (SS), Gulf of St. Lawrence (GSL), St. Lawrence Estuary (SLE) and Newfoundland Shelf]. Large-scale spatial patterns in size and lipid content were related to latitude, indicating that C. finmarchicus CV in the GSL and SLE were historically larger in body size, and had significantly higher lipid content compared with those in the GoM and the SS. The observed patterns of C. finmarchicus CV size and lipid storage capacity suggest that regional variation in whale prey energy content can play a role in the suitability of current and future whale foraging habitats in the Northwest Atlantic, with the larger lipid-rich individuals in the GSL providing a high-quality diet compared with those in southern areas.
{"title":"Spatial variability in size and lipid content of the marine copepod Calanus finmarchicus across the Northwest Atlantic continental shelves: implications for North Atlantic right whale prey quality","authors":"Laura K Helenius, Erica J H Head, Phoebe Jekielek, Christopher D Orphanides, Pierre Pepin, Geneviève Perrin, Stéphane Plourde, Marc Ringuette, Jeffrey A Runge, Harvey J Walsh, Catherine L Johnson","doi":"10.1093/plankt/fbad047","DOIUrl":"https://doi.org/10.1093/plankt/fbad047","url":null,"abstract":"Copepod size and energy content are influenced by regional and seasonal variation in temperature and food conditions, with implications for planktivorous consumers such as the endangered North Atlantic right whale (Eubalaena glacialis). Historical data (1990–2020) on Calanus finmarchicus stage CV copepodite prosome length and oil sac metrics were analyzed to determine the extent of variation in individual body size and estimated lipid and energy content in five regions of the Northwest Atlantic continental shelves [Gulf of Maine (GoM), Scotian Shelf (SS), Gulf of St. Lawrence (GSL), St. Lawrence Estuary (SLE) and Newfoundland Shelf]. Large-scale spatial patterns in size and lipid content were related to latitude, indicating that C. finmarchicus CV in the GSL and SLE were historically larger in body size, and had significantly higher lipid content compared with those in the GoM and the SS. The observed patterns of C. finmarchicus CV size and lipid storage capacity suggest that regional variation in whale prey energy content can play a role in the suitability of current and future whale foraging habitats in the Northwest Atlantic, with the larger lipid-rich individuals in the GSL providing a high-quality diet compared with those in southern areas.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"15 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138568621","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}
Frédéric Maps, Piotr Pasza Storożenko, Jędrzej Świeżewski, Sakina-Dorothée Ayata
In Arctic marine ecosystems, large planktonic copepods form a crucial hub of matter and energy. Their energy-rich lipid stores play a central role in marine trophic networks and the biological carbon pump. Since the past ~15 years, in situ imaging devices provide images whose resolution allows us to estimate an individual copepod’s lipid sac volume, and this reveals many ecological information inaccessible otherwise. One such device is the Lightframe On-sight Keyspecies Investigation. However, when done manually, weeks of work are needed by trained personnel to obtain such information for only a handful of sampled images. We removed this hurdle by training a machine learning algorithm (a convolutional neural network) to estimate the lipid content of individual Arctic copepods from the in situ images. This algorithm obtains such information at a speed (a few minutes) and a resolution (individuals, over half a meter on the vertical), allowing us to revisit historical datasets of in situ images to better understand the dynamics of lipid production and distribution and to develop efficient monitoring protocols at a moment when marine ecosystems are facing rapid upheavals and increasing threats.
{"title":"Automatic estimation of lipid content from in situ images of Arctic copepods using machine learning","authors":"Frédéric Maps, Piotr Pasza Storożenko, Jędrzej Świeżewski, Sakina-Dorothée Ayata","doi":"10.1093/plankt/fbad048","DOIUrl":"https://doi.org/10.1093/plankt/fbad048","url":null,"abstract":"In Arctic marine ecosystems, large planktonic copepods form a crucial hub of matter and energy. Their energy-rich lipid stores play a central role in marine trophic networks and the biological carbon pump. Since the past ~15 years, in situ imaging devices provide images whose resolution allows us to estimate an individual copepod’s lipid sac volume, and this reveals many ecological information inaccessible otherwise. One such device is the Lightframe On-sight Keyspecies Investigation. However, when done manually, weeks of work are needed by trained personnel to obtain such information for only a handful of sampled images. We removed this hurdle by training a machine learning algorithm (a convolutional neural network) to estimate the lipid content of individual Arctic copepods from the in situ images. This algorithm obtains such information at a speed (a few minutes) and a resolution (individuals, over half a meter on the vertical), allowing us to revisit historical datasets of in situ images to better understand the dynamics of lipid production and distribution and to develop efficient monitoring protocols at a moment when marine ecosystems are facing rapid upheavals and increasing threats.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"60 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534383","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}
Pub Date : 2023-11-29eCollection Date: 2024-01-01DOI: 10.1093/plankt/fbad050
Nicole Aberle, Charlotte Volpe, Mari-Ann Østensen, Sanna Majaneva
Mass occurrences of Periphylla periphylla in Norwegian fjords cause major concerns related to potential regime shifts that could affect ecosystem stability. 15 years of trawl data (2006-2015), complemented with comprehensive sampling in different areas and seasons (2018-2021) allowed new insights on the dynamics, structure and connectivity of P. periphylla populations within and beyond Trondheimsfjorden. Despite assumed population bursts, no clear trend on P. periphylla population size in Trondheimsfjorden were identified. Sampling frequency and population size suggest a local reproduction of P. periphylla, especially in the inner part of the fjord where young-of-the-year (YOY) individuals occur. Size variations occurred in relation to sampling month, thus pointing at seasonal patterns in growth and reproduction. No distinct population structure of P. periphylla populations within Trondheimsfjorden and over larger spatial scales (> 100 km) along the Norwegian coast was observed. Such poor geographic population structure provides evidence for a strong dispersal of P. periphylla, potentially triggered by frequent deep-water renewals of the fjords' basins that enable a high gene flow. Data on P. periphylla long-term dynamics, population structure and connectivity provide valuable information for ecosystem state assessments and enable the advancement of ecosystem management approaches, thus accounting for both stakeholder and ecosystem demands.
Periphylla periphylla在挪威峡湾的大规模出现引起了人们对可能影响生态系统稳定性的潜在制度转变的极大关注。15年的拖网数据（2006-2015年）以及不同地区和季节的综合采样（2018-2021年）使人们对特隆赫姆斯峡湾内外的P. periphylla种群的动态、结构和连通性有了新的认识。尽管存在假定的种群爆发，但特隆赫姆斯峡湾的 P. periphylla 种群数量并未出现明显趋势。采样频率和种群数量表明，P. periphylla 在当地繁殖，尤其是在峡湾内部，那里有当年幼体（YOY）出现。个体大小的变化与采样月份有关，因此表明了生长和繁殖的季节性规律。在特隆赫姆峡湾内和挪威沿岸更大的空间范围内（> 100 公里），没有观察到明显的P. periphylla种群结构。这种较差的地理种群结构证明，P. periphylla 的扩散能力很强，这可能是由于峡湾盆地的深水更新频繁，导致基因流动频繁所致。有关 P. periphylla 的长期动态、种群结构和连通性的数据为生态系统状态评估提供了宝贵的信息，有助于推进生态系统管理方法，从而兼顾利益相关者和生态系统的需求。
{"title":"Long-term dynamics, population structure and connectivity of the helmet jellyfish <i>Periphylla periphylla</i> in a Norwegian fjord and adjacent waters.","authors":"Nicole Aberle, Charlotte Volpe, Mari-Ann Østensen, Sanna Majaneva","doi":"10.1093/plankt/fbad050","DOIUrl":"10.1093/plankt/fbad050","url":null,"abstract":"<p><p>Mass occurrences of <i>Periphylla periphylla</i> in Norwegian fjords cause major concerns related to potential regime shifts that could affect ecosystem stability. 15 years of trawl data (2006-2015), complemented with comprehensive sampling in different areas and seasons (2018-2021) allowed new insights on the dynamics, structure and connectivity of <i>P. periphylla</i> populations within and beyond Trondheimsfjorden. Despite assumed population bursts, no clear trend on <i>P. periphylla</i> population size in Trondheimsfjorden were identified. Sampling frequency and population size suggest a local reproduction of <i>P. periphylla</i>, especially in the inner part of the fjord where young-of-the-year (YOY) individuals occur. Size variations occurred in relation to sampling month, thus pointing at seasonal patterns in growth and reproduction. No distinct population structure of <i>P. periphylla</i> populations within Trondheimsfjorden and over larger spatial scales (> 100 km) along the Norwegian coast was observed. Such poor geographic population structure provides evidence for a strong dispersal of <i>P. periphylla,</i> potentially triggered by frequent deep-water renewals of the fjords' basins that enable a high gene flow. Data on <i>P. periphylla</i> long-term dynamics, population structure and connectivity provide valuable information for ecosystem state assessments and enable the advancement of ecosystem management approaches, thus accounting for both stakeholder and ecosystem demands.</p>","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"46 1","pages":"59-71"},"PeriodicalIF":1.9,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10810686/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139570405","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}
The coastal ocean is experiencing changes in its physical and chemical properties that strongly affect planktonic metabolism assemblages and, in some cases, favor the occurrence of harmful algal blooms (HABs). Here we analyze the variations in phytoplankton biomass, gross and net primary production (NCP) as well as community respiration (CR) at two nearshore sampling sites (P1 and P2) located at a Mediterranean beach where high biomass HABs are recurrent. At P1, the most exposed site, phytoplankton chlorophyll was generally low, whereas dinoflagellates outbreaks of the genus Gymnodinium and Alexandrium were recurrent during summer at P2 spanning for 10–20 days. During bloom episodes, NCP increased up to 10-fold (>80 mmol O2 m−3 day−1). Contrastingly, variation in CR only reached an average of 1.8-fold the rates of non-bloom conditions. Remarkably, although the enhanced NCP:CR ratio suggests net autotrophic population growth, production per unit biomass at P1 and P2 was not significantly different. Our results indicate that although summer conditions favor the necessary primary production enhancement leading to HAB occurrences, the short-term dynamics driving high biomass episodes are not driven by metabolic variations but instead are governed by subtle accumulative processes of some flagellate species in the nutrient-rich nearshore environment.
{"title":"Phytoplankton metabolism in a stratified nearshore ecosystem with recurrent harmful algal blooms (HABs)","authors":"A Regaudie-de-Gioux, L Latorre, G Basterretxea","doi":"10.1093/plankt/fbad039","DOIUrl":"https://doi.org/10.1093/plankt/fbad039","url":null,"abstract":"The coastal ocean is experiencing changes in its physical and chemical properties that strongly affect planktonic metabolism assemblages and, in some cases, favor the occurrence of harmful algal blooms (HABs). Here we analyze the variations in phytoplankton biomass, gross and net primary production (NCP) as well as community respiration (CR) at two nearshore sampling sites (P1 and P2) located at a Mediterranean beach where high biomass HABs are recurrent. At P1, the most exposed site, phytoplankton chlorophyll was generally low, whereas dinoflagellates outbreaks of the genus Gymnodinium and Alexandrium were recurrent during summer at P2 spanning for 10–20 days. During bloom episodes, NCP increased up to 10-fold (&gt;80 mmol O2 m−3 day−1). Contrastingly, variation in CR only reached an average of 1.8-fold the rates of non-bloom conditions. Remarkably, although the enhanced NCP:CR ratio suggests net autotrophic population growth, production per unit biomass at P1 and P2 was not significantly different. Our results indicate that although summer conditions favor the necessary primary production enhancement leading to HAB occurrences, the short-term dynamics driving high biomass episodes are not driven by metabolic variations but instead are governed by subtle accumulative processes of some flagellate species in the nutrient-rich nearshore environment.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"2 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534382","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}
Vittoria Roncalli, Lauren N Block, Jeanette L Niestroy, Matthew C Cieslak, Ann M Castelfranco, Daniel K Hartline, Petra H Lenz
Abstract The high-latitude copepod Neocalanus flemingeri exploits the spring phytoplankton bloom to accumulate lipids for survival during food-limited periods and to fuel reproduction. At some point during development, lipid-accumulation ends and pre-adults molt into adults, descend to depth and enter a state of dormancy termed "diapause." How and when they determine to make this transition is still unresolved. According to one hypothesis, the trigger is their attaining a threshold amount of "lipid fullness." Alternatively, they might follow a genetic program, entering diapause within a narrow developmental window. To better understand the decision, a 5-week laboratory experiment was conducted to assess the effect of food quantity and type on lipid accumulation, biomass and gene expression in N. flemingeri copepodite stage CV. In fed individuals, the initial rate of lipid accumulation slowed by week 5, as a portion of CVs began to molt into adults. While changes in gene expression common to all fed individuals between weeks 1 and 3 were consistent with a developmental program, the duration of the CV stage was variable. Unfed individuals maintained lipid stores initially, suggesting physiological acclimatization to conserve energy. A comparison with gene expression profiles of field-collected individuals suggests similar responses to resources in the environment.
{"title":"Experimental analysis of development, lipid accumulation and gene expression in a high-latitude marine copepod","authors":"Vittoria Roncalli, Lauren N Block, Jeanette L Niestroy, Matthew C Cieslak, Ann M Castelfranco, Daniel K Hartline, Petra H Lenz","doi":"10.1093/plankt/fbad045","DOIUrl":"https://doi.org/10.1093/plankt/fbad045","url":null,"abstract":"Abstract The high-latitude copepod Neocalanus flemingeri exploits the spring phytoplankton bloom to accumulate lipids for survival during food-limited periods and to fuel reproduction. At some point during development, lipid-accumulation ends and pre-adults molt into adults, descend to depth and enter a state of dormancy termed \"diapause.\" How and when they determine to make this transition is still unresolved. According to one hypothesis, the trigger is their attaining a threshold amount of \"lipid fullness.\" Alternatively, they might follow a genetic program, entering diapause within a narrow developmental window. To better understand the decision, a 5-week laboratory experiment was conducted to assess the effect of food quantity and type on lipid accumulation, biomass and gene expression in N. flemingeri copepodite stage CV. In fed individuals, the initial rate of lipid accumulation slowed by week 5, as a portion of CVs began to molt into adults. While changes in gene expression common to all fed individuals between weeks 1 and 3 were consistent with a developmental program, the duration of the CV stage was variable. Unfed individuals maintained lipid stores initially, suggesting physiological acclimatization to conserve energy. A comparison with gene expression profiles of field-collected individuals suggests similar responses to resources in the environment.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"5 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135086973","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}
Abstract To investigate phytoplankton dynamics in response to variable winter weather conditions along the Sea of Japan, we conducted daily sampling in enclosed Maizuru Bay in five winters and found distinctive differences between 2016/2017 and 2018/2019. A clear diatom bloom occurred through the water column in moderately cold/snowy 2016/2017, whereas in exceptionally warm/snow-free 2018/2019 a small peak of dinoflagellates occurred only in the subsurface. Nutrient concentrations changed drastically depending on freshwater discharge and diatom growth in 2016/2017, showing a contrast with constant nutrient concentrations in 2018/2019. Copepod densities were ~10 times higher in 2016/2017 than in 2018/2019, indicating bottom-up effects in 2016/2017. As the absence of a diatom bloom from 2018/2019 can be attributed neither to nutrient limitation nor to grazing pressure, we hypothesize that wind mixing is a key factor triggering a diatom bloom. Within the five winters, clear diatom blooms were found only after strong winds and heavy precipitation including snowfall. Wind mixing would possibly promote the germination/rejuvenation of viable resting stage cells as inocula for a diatom bloom, while the growth and maintenance are supported by nutrient supply through freshwater discharge. In Maizuru Bay, winter production is likely activated by harsh weather conditions characteristic of this region.
{"title":"Bottom-up effects of variable winter weather conditions on phytoplankton dynamics in an enclosed bay: implications for ecological responses to climate change","authors":"Keita W Suzuki, Hanh T Dinh","doi":"10.1093/plankt/fbad046","DOIUrl":"https://doi.org/10.1093/plankt/fbad046","url":null,"abstract":"Abstract To investigate phytoplankton dynamics in response to variable winter weather conditions along the Sea of Japan, we conducted daily sampling in enclosed Maizuru Bay in five winters and found distinctive differences between 2016/2017 and 2018/2019. A clear diatom bloom occurred through the water column in moderately cold/snowy 2016/2017, whereas in exceptionally warm/snow-free 2018/2019 a small peak of dinoflagellates occurred only in the subsurface. Nutrient concentrations changed drastically depending on freshwater discharge and diatom growth in 2016/2017, showing a contrast with constant nutrient concentrations in 2018/2019. Copepod densities were ~10 times higher in 2016/2017 than in 2018/2019, indicating bottom-up effects in 2016/2017. As the absence of a diatom bloom from 2018/2019 can be attributed neither to nutrient limitation nor to grazing pressure, we hypothesize that wind mixing is a key factor triggering a diatom bloom. Within the five winters, clear diatom blooms were found only after strong winds and heavy precipitation including snowfall. Wind mixing would possibly promote the germination/rejuvenation of viable resting stage cells as inocula for a diatom bloom, while the growth and maintenance are supported by nutrient supply through freshwater discharge. In Maizuru Bay, winter production is likely activated by harsh weather conditions characteristic of this region.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":" 498","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135186633","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}
Different phytoplankton biomass estimations can provide information about abundance variation, but they are not able to describe the metabolic activity of species or groups within assemblages. Conversely, molecular traits are key for the metabolic dynamics in pelagic ecosystems. To investigate if the RNA/DNA and taxon-specific 18S ribosomal RNA (rRNA)/ribosomal DNA (rDNA) ratios could be used to assess and be indicators of metabolic activity in marine phytoplankton species, two Adriatic diatom species, Chaetoceros socialis and Skeletonema marinoi, were studied. Significant correlations between abundance, chlorophyll a, carbon content and proteins were found in individual and co-cultured growth experiments (from rs = 0.570 to rs = 0.986, P < 0.001). The biomass trend followed a logistic curve without providing additional information regarding diatom metabolic activity. In both experiments, the RNA/DNA and taxon-specific 18S rRNA/rDNA ratios of C. socialis and S. marinoi showed maximum values at the beginning of the growth phase, i.e as 23.2 ± 1.5 and 15.3 ± 0.8, and 16.2 ± 1.6 and 30.1 ± 5.4 after 2 and 6 days, respectively, in individual cultures, with a subsequent significant decrease in these values for both species in individual and co-culture experiments. Our results showed that these molecular rRNA/rDNA ratios expressed an activation of metabolism before the abundance increases, even in the presence of interspecific interaction between C. socialis and S. marinoi.
{"title":"RNA/DNA ratios as estimate of metabolic and functional traits in diatom species from the northwestern Adriatic Sea","authors":"Silvia Casabianca, Samuela Capellacci, Fabio Ricci, Giorgia Ravera, Geraldina Signa, Michele Scardi, Antonella Penna","doi":"10.1093/plankt/fbad042","DOIUrl":"https://doi.org/10.1093/plankt/fbad042","url":null,"abstract":"Different phytoplankton biomass estimations can provide information about abundance variation, but they are not able to describe the metabolic activity of species or groups within assemblages. Conversely, molecular traits are key for the metabolic dynamics in pelagic ecosystems. To investigate if the RNA/DNA and taxon-specific 18S ribosomal RNA (rRNA)/ribosomal DNA (rDNA) ratios could be used to assess and be indicators of metabolic activity in marine phytoplankton species, two Adriatic diatom species, Chaetoceros socialis and Skeletonema marinoi, were studied. Significant correlations between abundance, chlorophyll a, carbon content and proteins were found in individual and co-cultured growth experiments (from rs = 0.570 to rs = 0.986, P < 0.001). The biomass trend followed a logistic curve without providing additional information regarding diatom metabolic activity. In both experiments, the RNA/DNA and taxon-specific 18S rRNA/rDNA ratios of C. socialis and S. marinoi showed maximum values at the beginning of the growth phase, i.e as 23.2 ± 1.5 and 15.3 ± 0.8, and 16.2 ± 1.6 and 30.1 ± 5.4 after 2 and 6 days, respectively, in individual cultures, with a subsequent significant decrease in these values for both species in individual and co-culture experiments. Our results showed that these molecular rRNA/rDNA ratios expressed an activation of metabolism before the abundance increases, even in the presence of interspecific interaction between C. socialis and S. marinoi.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136014831","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}
Abstract Zooplankton in the Barents Sea have been monitored annually with a standard procedure with determination of size-fractioned biomass since the mid-1980s. Biomass of copepods and cladocerans was estimated based on measured abundance and individual weights taken from literature. Calanus species were dominant, making up ~85% of the estimated biomass of copepods. The second most important taxon was Oithona spp. (~0.5 g dry weight (dw) m−2, ~10%), followed by Metridia spp. (~0.15 g dw m−2, 2–3%) and Pseudocalanus spp. (0.10–0.15 g dw m−2, 1–5%). Estimated biomass of cladoceran taxa (Evadne and Podon) was low (0.01 g dw m−2). Calanus spp. contributed most of the biomass of the medium size fraction (1–2 mm), whereas small copepod species (Oithona, Pseudocalanus and others) contributed to the small size fraction (<1 mm). Estimated biomass of Calanus spp. and of the sum of small copepod species were both positively correlated with measured total zooplankton biomass (R2 = 0.72 and 0.34, respectively). The biomass ratio of small copepod species to Calanus was similar in Atlantic and Arctic water masses (~0.15–0.2) but tended to increase with decreasing total biomass. This suggests a shift to relatively larger roles of small copepods as Calanus and total biomass decrease.
摘要自20世纪80年代中期以来，每年都对巴伦支海的浮游动物进行监测，并采用标准程序确定大小分馏生物量。根据文献中测量的丰度和个体重量估算了桡足类和枝海类的生物量。桡足类中以虾足类占优势，约占总生物量的85%。其次是Oithona spp. (~0.5 g dw m−2，~10%)，其次是Metridia spp. (~0.15 g dw m−2,2 - 3%)和pseudoalanus spp. (0.10 ~0.15 g dw m−2,1-5%)。枝海类群(Evadne和Podon)的估算生物量较低(0.01 g dw m−2)。中等大小部分(1 ~ 2 mm)的生物量主要由Calanus sp .贡献，而小桡足类(Oithona、pseudoalanus等)的生物量则为1 mm。小桡足类和小桡足类总生物量与浮游动物总生物量呈显著正相关(R2分别为0.72和0.34)。大西洋和北极水体中，小桡足类与大桡足类的生物量之比相似(~0.15 ~ 0.2)，但随总生物量的减少而增加。这表明随着小桡足类动物数量和总生物量的减少，小桡足类动物的作用逐渐增大。
{"title":"Abundance and biomass of copepods and cladocerans in Atlantic and Arctic domains of the Barents Sea ecosystem","authors":"Hein Rune Skjoldal, Johanna Myrseth Aarflot","doi":"10.1093/plankt/fbad043","DOIUrl":"https://doi.org/10.1093/plankt/fbad043","url":null,"abstract":"Abstract Zooplankton in the Barents Sea have been monitored annually with a standard procedure with determination of size-fractioned biomass since the mid-1980s. Biomass of copepods and cladocerans was estimated based on measured abundance and individual weights taken from literature. Calanus species were dominant, making up ~85% of the estimated biomass of copepods. The second most important taxon was Oithona spp. (~0.5 g dry weight (dw) m−2, ~10%), followed by Metridia spp. (~0.15 g dw m−2, 2–3%) and Pseudocalanus spp. (0.10–0.15 g dw m−2, 1–5%). Estimated biomass of cladoceran taxa (Evadne and Podon) was low (0.01 g dw m−2). Calanus spp. contributed most of the biomass of the medium size fraction (1–2 mm), whereas small copepod species (Oithona, Pseudocalanus and others) contributed to the small size fraction (&lt;1 mm). Estimated biomass of Calanus spp. and of the sum of small copepod species were both positively correlated with measured total zooplankton biomass (R2 = 0.72 and 0.34, respectively). The biomass ratio of small copepod species to Calanus was similar in Atlantic and Arctic water masses (~0.15–0.2) but tended to increase with decreasing total biomass. This suggests a shift to relatively larger roles of small copepods as Calanus and total biomass decrease.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136015701","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}
Abstract The patterns of species diversity of plankton functional groups (PFGs) remain poorly understood although they matter greatly for marine ecosystem functioning. Here, we use an ensemble of empirical species distribution models for 845 plankton species to estimate the global species richness of three phytoplankton and 11 zooplankton functional groups as a function of objectively selected environmental predictors. The annual mean species richness of all PFGs decreases from the low to the high latitudes, but the steepness and the shape of this decrease vary significantly across PFGs. Pteropods, small copepods (Oithonids and Poecilostomatoids) and Salps have the steepest latitudinal gradients, whereas Amphipods and the three phytoplankton groups have the weakest ones. Temperature, irradiance and nutrient concentration are the first-order control on the latitudinal richness patterns, whilst the environmental conditions associated to upwelling systems, boundary currents and oxygen minimum zones modulate the position of the peaks and troughs in richness. The species richness of all PFGs increases with net primary production but decreases with particles size and the efficiency of the biological carbon pump. Our study puts forward emergent biodiversity–ecosystem functioning relationships and hypotheses about their underlying drivers for future field-based and modelling research.
{"title":"Global gradients in species richness of marine plankton functional groups","authors":"Fabio Benedetti, Nicolas Gruber, Meike Vogt","doi":"10.1093/plankt/fbad044","DOIUrl":"https://doi.org/10.1093/plankt/fbad044","url":null,"abstract":"Abstract The patterns of species diversity of plankton functional groups (PFGs) remain poorly understood although they matter greatly for marine ecosystem functioning. Here, we use an ensemble of empirical species distribution models for 845 plankton species to estimate the global species richness of three phytoplankton and 11 zooplankton functional groups as a function of objectively selected environmental predictors. The annual mean species richness of all PFGs decreases from the low to the high latitudes, but the steepness and the shape of this decrease vary significantly across PFGs. Pteropods, small copepods (Oithonids and Poecilostomatoids) and Salps have the steepest latitudinal gradients, whereas Amphipods and the three phytoplankton groups have the weakest ones. Temperature, irradiance and nutrient concentration are the first-order control on the latitudinal richness patterns, whilst the environmental conditions associated to upwelling systems, boundary currents and oxygen minimum zones modulate the position of the peaks and troughs in richness. The species richness of all PFGs increases with net primary production but decreases with particles size and the efficiency of the biological carbon pump. Our study puts forward emergent biodiversity–ecosystem functioning relationships and hypotheses about their underlying drivers for future field-based and modelling research.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136015703","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}
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