Vittoria Roncalli, Lauren N Block, Jeanette L Niestroy, Matthew C Cieslak, Ann M Castelfranco, Daniel K Hartline, Petra H Lenz
{"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}
{"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}
{"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}
{"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}
{"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}
Patricia Nogueira, Ana B Barbosa, Rita B Domingues
{"title":"Impacts of sample storage time on estimates of phytoplankton abundance: how long is too long?","authors":"Patricia Nogueira, Ana B Barbosa, Rita B Domingues","doi":"10.1093/plankt/fbad041","DOIUrl":"https://doi.org/10.1093/plankt/fbad041","url":null,"abstract":"Abstract Phytoplankton play a key role in marine ecosystems, making the accurate quantification of functional groups/species, using standardized microscopy techniques, essential in many research efforts. In this study we aimed to evaluate the effects of (a) storage time on the abundance of microphytoplankton in samples fixed with acid Lugol’s solution; (b) storage time on the abundance of pico- and nanophytoplankton in frozen microscopy slides; (c) storage time on the abundance of pico- and nanophytoplankton in fixed refrigerated samples and (d) storage protocol (refrigerated versus frozen) on the abundance of pico- and nanophytoplankton. Microphytoplankton were analyzed using inverted microscopy, and pico- and nanophytoplankton using epifluorescence microscopy. Results indicate storage time negatively impacted the abundances of all phytoplankton size classes; however, effects were group-specific. For accurate abundance estimates, we suggest that samples fixed with acid Lugol’s should be analyzed within 30 and 180 days, for dinoflagellates/total microphytoplankton and diatoms, respectively. For picoeukaryotes, glutaraldehyde fixed samples should be kept refrigerated for up to 4 days, and slides should be prepared immediately before observation. It is recommended that authors specify the exact lag times between sample collection, fixation and analysis, to allow the comparability of phytoplankton datasets across different studies and/or monitoring programs.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135689980","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":"Composition patterns of surface mesozooplankton in the zonal fronts of Drake Passage","authors":"Octavio Esquivel-Garrote, Erik Muxagata","doi":"10.1093/plankt/fbad040","DOIUrl":"https://doi.org/10.1093/plankt/fbad040","url":null,"abstract":"Abstract Zooplankton is the main food source for higher trophic levels in marine environments. In the Southern Ocean, the distribution of zooplankton is related to the physical gradient of the Antarctic Circumpolar Current (ACC) fronts. Our objective was to determinate the distribution of mesozooplankton in relation to the ACC fronts in the Drake Passage. Samples were collected with the Continuous Plankton Recorder in two transects. Mesozooplankton was associated with environmental variables. High mesozooplankton abundances were recorded in the Subantarctic Front in 2017 and in the Antarctic Zone in 2016. A total of 81 taxa and 23 species in 2016 and 31 in 2017 were identified. Copepoda was the most abundant group (89%), and Centropages brachiatus (3 872 ind. m−3) and Oithona spp. (2 916 ind. m−3) were the most abundant copepod taxa. Mesozooplankton abundance and composition were influenced by front variability. Taxa were contracted northward on 2016 and displaced southward in 2017 and linked to chlorophyll a (Chl a) values recorded in the coastal shelf of South America. Chl a values registered close to Antarctic Peninsula were not linked to mesozooplankton abundance. Changes in abundances of certain taxa may reflect distinct climate events. These changes may impact the availability of prey for higher trophic levels, either through displacement for food or food availability.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135477832","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":"Shifts in survival and reproduction after chronic warming enhance the potential of a marine copepod to persist under extreme heat events.","authors":"Carlos de Juan, Albert Calbet, Enric Saiz","doi":"10.1093/plankt/fbad037","DOIUrl":"10.1093/plankt/fbad037","url":null,"abstract":"<p><p>The study of a species' thermal tolerance and vital rates responses provides useful metrics to characterize its vulnerability to ocean warming. Under prolonged thermal stress, plastic and adaptive processes can adjust the physiology of organisms. Yet it is uncertain whether the species can expand their upper thermal limits to cope with rapid and extreme changes in environmental temperature. In this study, we reared the marine copepod <i>Paracartia grani</i> at control (19°C) and warmer conditions (25°C) for >18 generations and assessed their survival and fecundity under short-term exposure to a range of temperatures (11-34°C). After multigenerational warming, the upper tolerance to acute exposure (24 h) increased by 1-1.3°C, although this enhancement decreased to 0.3-0.8°C after longer thermal stress (7 days). Warm-reared copepods were smaller and produced significantly fewer offspring at the optimum temperature. No shift in the thermal breadth of the reproductive response was observed. Yet the fecundity rates of the warm-reared copepods in the upper thermal range were up to 21-fold higher than the control. Our results show that chronic warming improved tolerance to stress temperatures and fecundity of <i>P. grani</i>, therefore, enhancing its chances to persist under extreme heat events.</p>","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"45 5","pages":"751-762"},"PeriodicalIF":2.1,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539201/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41130489","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}
Emily Y-S Chen, Emilia Trudnowska, Katarzyna Błachowiak-Samołyk
{"title":"It’s a female’s world: sex ratio of polar pelagic ostracods tested across multiple spatiotemporal scales","authors":"Emily Y-S Chen, Emilia Trudnowska, Katarzyna Błachowiak-Samołyk","doi":"10.1093/plankt/fbad038","DOIUrl":"https://doi.org/10.1093/plankt/fbad038","url":null,"abstract":"Abstract Biased sex ratios are commonly found in nature and were also observed in this study on pelagic ostracods in both the Arctic and Southern Oceans. Because changes in sex ratio may occur in response to environmental perturbations, studying this aspect in polar regions as they continue to warm is of ecological importance. Here, a robust spatiotemporal dataset of historical and contemporary sex data was compiled to explore variation in ostracod sex ratio with respect to species, depth, region, season and ontogeny. Global ostracod populations in both the Arctic and Antarctic demonstrated a stable female bias of ~ 60–70% over all tested factors. This female bias was even higher when only the premature A-1 stage was considered, regardless of the factor. The widespread stability in stage-specific sex ratio and its subtle changes, especially in the interannual context, show that marine Ostracoda has the potential to be a model organism for more comprehensive sex ratio research, but deeper investigation into their ecology and reproduction is necessary.","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135049577","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":"Pioneers of plankton research: Carl Chun (1852–1914)","authors":"J. Dolan","doi":"10.1093/plankt/fbad036","DOIUrl":"https://doi.org/10.1093/plankt/fbad036","url":null,"abstract":"","PeriodicalId":16800,"journal":{"name":"Journal of Plankton Research","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47113521","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}