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  • 1
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    PANGAEA
    In:  Supplement to: Tremblay, Nelly; Cascella, Kévin; Toullec, Jean-Yves; Held, Christoph; Fielding, Sophie; Tarling, Geraint A; Abele, Doris (submitted): Gene expression and physiological changes of the Antarctic krill Euphausia superba under different hypoxia intensities.
    Publication Date: 2023-02-16
    Description: Antarctic krill (Euphausia superba) from South Georgia comprise one of the most northern and abundant krill stocks. South Georgia waters are undergoing rapid warming, as a result of climate change, which in turn could alter the oxygen concentration of the water. We investigated gene expression in Antarctic krill related to aerobic metabolism, antioxidant defence, and heat-shock response under severe (2.5% O2 saturation or 0.6 kPa) and threshold (20% O2 saturation or 4 kPa) hypoxia exposure compared to in situ levels (normoxic; 100% O2 saturation or 21 kPa). Biochemical metabolic and oxidative stress indicators complemented the genic expression analysis to detect in vivo signs of stress during the hypoxia treatments. Expression levels of the genes citrate synthase (CS), mitochondrial manganese superoxide dismutase (SODMn-m) and one heat-shock protein isoform (E) were higher in euphausiids incubated 6 h at 20% O2 saturation than in animals exposed to control (normoxic) conditions. All biochemical antioxidant defence parameters remained unchanged among treatments. Levels of lipid peroxidation were raised after 6 h of severe hypoxia. Overall, short-term exposure to hypoxia altered mitochondrial metabolic and antioxidant capacity, but did not induce anaerobic metabolism. Antarctic krill are swarming organisms and may experience short periods of hypoxia when present in dense swarms. A future, warmer Southern ocean, where oxygen saturation levels are decreased, may result in smaller, less dense swarms as they act to avoid greater levels of hypoxia.
    Keywords: Rectangular midwater trawl 4500 µm; RMT8; South_Georgia_RMT; South Georgia Island
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 2
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    PANGAEA
    In:  Supplement to: Tremblay, Nelly; Abele, Doris (2016): Response of three krill species to hypoxia and warming: an experimental approach to oxygen minimum zones expansion in coastal ecosystems. Marine Ecology, 37(1), 179-199, https://doi.org/10.1111/maec.12258
    Publication Date: 2023-02-16
    Description: To understand the adaptation of euphausiid (krill) species to oxygen minimum zones (OMZ), respiratory response and stress experiments combining hypoxia/reoxygenation exposure with warming were conducted. Experimental krill species were obtained from the Antarctic (South Georgia area), the Humboldt Current system (HCS, Chilean coast), and the Northern California Current system (NCCS, Oregon). Euphausia mucronata from the HCS shows oxyconforming or oxygen partial pressure (pO2)-dependent respiration below 80% air saturation (18 kPa). Normoxic subsurface oxygenation in winter posed a "high oxygen stress" for this species. The NCCS krill, Euphausia pacifica, and the Antarctic krill, Euphausia superba maintain respiration rates constant down to low critical pO2 values of 6 kPa (30% air saturation) and 11 kPa (55% air saturation), respectively. Antarctic krill had the lowest antioxidant enzyme activities, but the highest concentrations of the molecular antioxidant glutathione (GSH) and was not affected by 6 h exposure to moderate hypoxia. Temperate krill species had higher SOD (superoxide dismutase) values in winter than in summer, which relate to higher winter metabolic rate (E. pacifica). In all species, antioxidant enzyme activities remained constant during hypoxic exposure at habitat temperature. Warming by 7°C above habitat temperature in summer increased SOD activities and GSH levels in E. mucronata (HCS), but no oxidative damage occurred. In winter, when the NCCS is well mixed and the OMZ is deeper, +4°C of warming combined with hypoxia represents a lethal condition for E. pacifica. In summer, when the OMZ expands upwards (100 m subsurface), antioxidant defences counteracted hypoxia and reoxygenation effects in E. pacifica, but only at mildly elevated temperature (+2°C). In this season, experimental warming by +4°C reduced antioxidant activities and the hypoxia combination again caused mortality of exposed specimens. We conclude that a climate change scenario combining warming and hypoxia represents a serious threat to E. pacifica and, as a consequence, NCCS food webs.
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 3
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    PANGAEA
    In:  Supplement to: Tremblay, Nelly; Werner, Thorsten; Hünerlage, Kim; Buchholz, Friedrich; Abele, Doris; Meyer, Bettina; Brey, Thomas (2014): Euphausiid respiration model revamped: Latitudinal and seasonal shaping effects on krill respiration rates. Ecological Modelling, 291, 233-241, https://doi.org/10.1016/j.ecolmodel.2014.07.031
    Publication Date: 2023-02-16
    Description: Euphausiids constitute major biomass component in shelf ecosystems and play a fundamental role in the rapid vertical transport of carbon from the ocean surface to the deeper layers during their daily vertical migration (DVM). DVM depth and migration patterns depend on oceanographic conditions with respect to temperature, light and oxygen availability at depth, factors that are highly dependent on season in most marine regions. Changes in the abiotic conditions also shape Euphausiid metabolism including aerobic and anaerobic energy production. Here we introduce a global krill respiration model which includes the effect of latitude (LAT), the day of the year of interest (DoY), and the number of daylight hours on the day of interest (DLh), in addition to the basal variables that determine ectothermal oxygen consumption (temperature, body mass and depth) in the ANN model (Artificial Neural Networks). The newly implemented parameters link space and time in terms of season and photoperiod to krill respiration. The ANN model showed a better fit (r**2=0.780) when DLh and LAT were included, indicating a decrease in respiration with increasing LAT and decreasing DLh. We therefore propose DLh as a potential variable to consider when building physiological models for both hemispheres. We also tested for seasonality the standard respiration rate of the most common species that were investigated until now in a large range of DLh and DoY with Multiple Linear Regression (MLR) or General Additive model (GAM). GAM successfully integrated DLh (r**2= 0.563) and DoY (r**2= 0.572) effects on respiration rates of the Antarctic krill, Euphausia superba, yielding the minimum metabolic activity in mid-June and the maximum at the end of December. Neither the MLR nor the GAM approach worked for the North Pacific krill Euphausia pacifica, and MLR for the North Atlantic krill Meganyctiphanes norvegica remained inconclusive because of insufficient seasonal data coverage. We strongly encourage comparative respiration measurements of worldwide Euphausiid key species at different seasons to improve accuracy in ecosystem modelling.
    Type: Dataset
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, 350.8 kBytes
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  • 4
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    PANGAEA
    In:  Supplement to: Tremblay, Nelly; Caamal-Monsreal, Claudia; Ortega, Karen; Díaz, Fernando; Celdrán, David; Rosas, Carlos (in review): Measurement of aerobic scope during the whole embryonic development of a cephalopod. Marine Biology
    Publication Date: 2023-02-16
    Description: In the context of global warming, the present study aimed to identify at which stages the embryos of the holobenthic species Octopus maya are the most sensitive to temperature. We used temperature as a tool to induce minimum (TIMR-min: 11°C) and maximum metabolic rates (TIMR-max: 30°C) on embryos that came from three wild females caught off Sisal harbor (21°10'N, 90°02'W; Yucatán, Mexico) in March 2016. Higher metabolic rate values were recorded at stages XV and XVI, when the three hearts start beating, compared to stage X, when organogenesis begins. The factorial metabolic scope (FMS = TIMR-max ? TIMR-min) was higher at stages XV and XVI than the more mature stages, establishing stage XVII as the most vulnerable. High temperature exposure applied only during the earliest developmental stages (until stage XV) could have adaptive advantages if spawning occurs during hot waves in tropical coastal zones where the embryos are incubated or used for aquaculture purposes by shortening the time before hatching without physiological costs.
    Keywords: Method comment; off_Sisal_Harbor; Oxygen consumption per wet mass; Stage; Temperature, water
    Type: Dataset
    Format: text/tab-separated-values, 1164 data points
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  • 5
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    PANGAEA
    In:  Universidad Nacional Autonoma de Mexico | Supplement to: Olivares, Alberto; Rodríguez-Fuentes, Gabriela; Mascaró, Maite; Sanchez Arteaga, Ariadna; Ortega, Karen; Caamal-Monsreal, Claudia; Tremblay, Nelly; Rosas, Carlos (2019): Maturation trade-offs in octopus females and their progeny: energy, digestion and defence indicators. PeerJ, 7, e6618, https://doi.org/10.7717/peerj.6618
    Publication Date: 2023-02-16
    Description: Morphological changes of Octopus mimus females were evaluated during ovarian development. Digestive gland (DG) and ovaries wet weight were assessed to obtain gonadosomatic and hepatosomatic indices. Obtained from a group of females placed in tanks until spawn, embryos were incubated and sampled during development. Females (DG and ovaries), embryos (at different stages of development) and paralarvae (one and three days old) were preserved for energetic metabolites (glucose, glycogen, cholesterol, triacylglycerides, and protein concentrations), digestive enzyme activities (acidic proteases, alkaline proteases, trypsin and lipases), detoxification (acetylcholinesterase and carboxylesterase activities), and oxidative stress indicators (catalase activity, glutathione-s-transferase activity, superoxide dismutase activity, redox potential, total glutathione and lipid peroxidation).
    Type: Dataset
    Format: application/zip, 57.4 kBytes
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  • 6
    Publication Date: 2023-02-16
    Keywords: Citrate synthase mean normalized expression gene expression; Heat-shock protein 70 isoform A gene expression; Heat-shock protein 70 isoform C gene expression; Heat-shock protein 70 isoform D gene expression; Heat-shock protein 70 isoform E gene expression; Rectangular midwater trawl 4500 µm; RMT8; South_Georgia_RMT; South Georgia Island; Superoxide dismutase manganese (cytosolic) gene expression; Superoxide dismutase manganese (mitochondrial) gene expression; Treatment
    Type: Dataset
    Format: text/tab-separated-values, 217 data points
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  • 7
    Publication Date: 2023-02-16
    Keywords: DEPTH, water; Haemolymph, lactate; Rectangular midwater trawl 4500 µm; RMT8; South_Georgia_RMT; South Georgia Island
    Type: Dataset
    Format: text/tab-separated-values, 51 data points
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  • 8
    Publication Date: 2023-02-16
    Keywords: CTD; DATE/TIME; DEPTH, water; Event label; HCS; Humboldt current system; Latitude of event; Longitude of event; NCCS; Northern California current system; Off Dichiato, Chile; Off Newport, USA; Oxygen saturation; Salinity; SG; South Georgia Island; Temperature, water
    Type: Dataset
    Format: text/tab-separated-values, 3333 data points
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  • 9
    Publication Date: 2023-02-16
    Keywords: Calculated; DATE/TIME; Event label; Haemolymph, lactate; HCS; Humboldt current system; Latitude of event; Longitude of event; NCCS; Northern California current system; Off Dichiato, Chile; Off Newport, USA; Respiration rate, oxygen; Sample code/label; SG; South Georgia Island; Species
    Type: Dataset
    Format: text/tab-separated-values, 318 data points
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  • 10
    Publication Date: 2023-07-09
    Description: We conducted a mesocosm experiment with an integrated multiple driver design to assess the impact of future global change scenarios on plankton, a key component of marine food webs. The experimental treatments were based on the RCP 6.0 and 8.5 scenarios developed by the IPCC, which were Extended (ERCP) to integrate the future predicted changing nutrient inputs into coastal waters. The mesocosm experiment was conducted over three weeks in late-summer (August-September) 2018. Seawater containing a natural plankton community was collected from the coastal North Sea. At the onset of the experiment, CO2 saturated seawater was added to the ERCP scenario mesocosms to adjust pCO2 and pH levels for each scenario. To create a realistic environment, we also manipulated the atmospheric pCO2 in the enclosed mesocosm tanks throughout the experiment. Seawater temperature was adjusted daily according to the current North Sea temperature measured at the Helgoland Roads for the Ambient, and 1.5°C and 3.0°C warmer for the ERCP 6.0 and ERCP 8.5 scenarios, respectively. Dissolved nutrient concentrations were determined at the onset of the experiment and adjusted to reach the desired N:P ratios. Samples were taken in an interval of 1-3 days depending on the phytoplankton bloom development, and community composition, except for the large mesozooplankton, was monitored throughout the experiment period.
    Keywords: Acineta sp., biomass as carbon; Alkalinity, total; Asterionellopsis glacialis, biomass as carbon; Bacillaria paxillifer, biomass as carbon; Bacteriastrum hyalinum, biomass as carbon; Bacterioplankton, biomass as carbon; Balanion comatum, biomass as carbon; Bellerochea malleus, biomass as carbon; Carbon, organic, particulate; Cerataulina pelagica, biomass as carbon; Ceratium furca, biomass as carbon; Ceratium fusus, biomass as carbon; Ceratium horridum, biomass as carbon; Ceratium lineatum, biomass as carbon; Ceratium macroceros, biomass as carbon; Ceratium tripos, biomass as carbon; cf. Heterophrys sp., biomass as carbon; Chaetoceros curvisetus, biomass as carbon; Chaetoceros decipiens, biomass as carbon; Chaetoceros densus, biomass as carbon; Chaetoceros didymus, biomass as carbon; Chaetoceros eibenii, biomass as carbon; Chaetoceros socialis, biomass as carbon; Chaetoceros sp., biomass as carbon; Chrysosphaera sp., biomass as carbon; Ciliophora indeterminata, biomass as carbon; Copepoda; Coscinodiscus sp., biomass as carbon; Cylindrotheca closterium, biomass as carbon; Day of experiment; Detonula pumila, biomass as carbon; Diatoms, pennales indeterminata, biomass as carbon; Dinophyceae indeterminata, biomass as carbon; Dinophysis sp., biomass as carbon; Diplopsalis complex, biomass as carbon; Ditylum brightwellii, biomass as carbon; Emiliania huxleyi, biomass as carbon; Eucampia zodiacus, biomass as carbon; Eutintinnus sp., biomass as carbon; Eutreptiella sp., biomass as carbon; Gonyaulax sp., biomass as carbon; Guinardia delicatula, biomass as carbon; Guinardia flaccida, biomass as carbon; Gymnodinium sp., biomass as carbon; Gyrodinium sp., biomass as carbon; Helicostomella subulata, biomass as carbon; Hydrozoa; Katodinium glaucum, biomass as carbon; Laboea strobila, biomass as carbon; Lauderia annulata, biomass as carbon; Leegaardiella sol, biomass as carbon; Leptocylindrus danicus, biomass as carbon; Leptocylindrus minimus, biomass as carbon; Light intensity; Lohmanniella oviformis, biomass as carbon; Melosira moniliformis, biomass as carbon; MESO; Mesocosm experiment; Mesodinium rubrum, biomass as carbon; Mesozooplankton, other groups; Microzooplankton, biomass as carbon; Nitrogen, inorganic, dissolved; Nitrogen, organic, particulate; Noctiluca scintillans; Paralia sulcata, biomass as carbon; Pelagostrobilidium sp., biomass as carbon; Penilia avirostris; pH; Phaeocystis sp., biomass as carbon; Phalacroma rotundatum, biomass as carbon; Phosphorus, inorganic, dissolved; Phosphorus, organic, particulate; Phytoflagellate indeterminata, biomass as carbon; Phytoplankton, biomass as carbon; PlanktoSERV_exp; Pleurosigma/Gyrosigma, biomass as carbon; Proboscia alata, biomass as carbon; Prorocentrum micans, biomass as carbon; Prorocentrum minimum, biomass as carbon; Protoceratium reticulatum, biomass as carbon; Protoperidinium bipes, biomass as carbon; Protoperidinium conicum, biomass as carbon; Protoperidinium ovatum, biomass as carbon; Protoperidinium sp., biomass as carbon; Pseudo-nitzschia delicatissima complex, biomass as carbon; Pseudo-nitzschia seriata complex, biomass as carbon; Pyrophacus horologium, biomass as carbon; Replicate; Rhizosolenia imbricata, biomass as carbon; Rhizosolenia styliformis, biomass as carbon; Salinity; Scrippsiella sp., biomass as carbon; Scuticociliate indeterminata, biomass as carbon; Silica, dissolved; Skeletonema sp., biomass as carbon; Stenosemella sp., biomass as carbon; Strobilidium sp., biomass as carbon; Strombidinopsis sp., biomass as carbon; Strombidium emergens, biomass as carbon; Strombidium sp., biomass as carbon; Temperature, water; Thalassionema nitzschioides, biomass as carbon; Thalassiosira minima, biomass as carbon; Thalassiosira nordenskioeldii, biomass as carbon; Thalassiosira sp., biomass as carbon; Tiarina fusus, biomass as carbon; Tintinnida indeterminata, biomass as carbon; Tintinnopsis sp., biomass as carbon; Tontonia gracillima, biomass as carbon; Treatment
    Type: Dataset
    Format: text/tab-separated-values, 10962 data points
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