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  • 11
    Publication Date: 2023-10-12
    Description: Gelatinous and soft-bodied zooplankton (GZ) have long been considered to have low energetic value and are insufficient to sustain higher trophic levels. However, the nutritional composition of GZ is often poorly known for entire groups, ignoring species-, size- and stage-specific differences. Organic matter and elemental composition (carbon and nitrogen) were measured for more than 1000 specimens from 34 GZ species collected in the Northeast Pacific between 2014-2020 using a variety of nets (CanTrawl250, Bongo net, Juday net, Multinet Medi, Dip net, Midwater trawl, Neuston net). Size-dependent variability was shown for several species. Differences in organic content and elemental composition by development stage were observed in a salp and scyphomedusa species, highlighting the need to consider life cycle stages separately.
    Keywords: Ash free dry mass; Ash mass; Ash mass per individual; Biomass, ash free dry mass; Biomass, ash free dry mass per individual; Calculated; Carbon, total; Carbon/Nitrogen ratio; Carbon and nitrogen and sulfur (CNS) isotope element analyzer, Elementar, Vario Micro Cube; Ctenophores; DEPTH, water; Doliolids; Dry mass per individual; Duration; Edwards Modulyo Freeze Dryer (Oakville, Ontario, CA); Gastropods; Identification; Jellyfish; LATITUDE; Life stage; LONGITUDE; Measured using callipers; Muffel furnace, 500 °C, LOI; Nitrogen, total; Number of individuals; Parameter; Salish Sea; salps; Sample type; Size; Species; Station label; Tissue, dry mass; VID; Visual identification; Weighted; Wet mass
    Type: Dataset
    Format: text/tab-separated-values, 8823 data points
    Location Call Number Limitation Availability
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  • 12
    Publication Date: 2024-03-15
    Description: Pacific salmon stocks are in decline with climate change named as a contributing factor. The North Pacific coast of British Columbia is characterized by strong temporal and spatial heterogeneity in ocean conditions with upwelling events elevating CO2 levels up to 10-fold those of pre-industrial global averages. Early life stages of pink salmon have been shown to be affected by these CO2 levels, and juveniles naturally migrate through regions of high CO2 during the energetically costly phase of smoltification. To investigate the physiological response of out-migrating wild juvenile pink salmon to these naturally occurring elevated CO2 levels, we captured fish in Georgia Strait, British Columbia and transported them to a marine lab (Hakai Institute, Quadra Island) where fish were exposed to one of three CO2 levels (850, 1500 and 2000 μatm CO2) for 2 weeks. At 1/2, 1 and 2 weeks of exposure, we measured their weight and length to calculate condition factor (Fulton's K), as well as haematocrit and plasma [Cl-]. At each of these times, two additional stressors were imposed (hypoxia and temperature) to provide further insight into their physiological condition. Juvenile pink salmon were largely robust to elevated CO2 concentrations up to 2000 μatm CO2, with no mortality or change in condition factor over the 2-week exposure duration. After 1 week of exposure, temperature and hypoxia tolerance were significantly reduced in high CO2, an effect that did not persist to 2 weeks of exposure. Haematocrit was increased by 20% after 2 weeks in the CO2 treatments relative to the initial measurements, while plasma [Cl-] was not significantly different. Taken together, these data indicate that juvenile pink salmon are quite resilient to naturally occurring high CO2 levels during their ocean outmigration.
    Keywords: Alkalinity, total; Alkalinity, total, standard deviation; Animalia; Aragonite saturation state; Aragonite saturation state, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Calcite saturation state; Calcite saturation state, standard deviation; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Calculated using seacarb after Orr et al. (2018); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; Chloride in plasma; Chordata; Coast and continental shelf; Comment; Containers and aquaria (20-1000 L or 〈 1 m**2); Critical thermal maximum; DATE/TIME; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Fugacity of carbon dioxide in seawater, standard deviation; Fulton's condition factor; Granite_Bay; Growth/Morphology; Haematocrit; Height; Identification; Laboratory experiment; Length; Mass; Nekton; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Oncorhynchus gorbuscha; Other studied parameter or process; Oxygen; Oxygen saturation; Oxygen saturation change; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Registration number of species; Salinity; Salinity, standard deviation; Species; Temperature, water; Temperature, water, standard deviation; Time in minutes; Time of day; Treatment; Type; Uniform resource locator/link to reference
    Type: Dataset
    Format: text/tab-separated-values, 44249 data points
    Location Call Number Limitation Availability
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  • 13
    Publication Date: 2024-04-25
    Description: Climate change and anthropogenic disturbances, among other factors, can change the seawater stoichiometry (C/N/P) and consequently elemental ratios of phytoplankton. This change in prey stoichiometry may not be tolerated by all grazer/predator species. Gelatinous and soft-bodied zooplankton (GZ) are suggested to be more resilient to such changes. We sampled GZ species (12 taxa in total) in the Northeast Pacific off British Columbia (Canada), determined their phosphorus (P) content and elemental ratios (C/P, N/P), and analysed intraspecific variability associated with size and ontogeny. P was determined as orthophosphate after acidic oxidative hydrolysis with 5 % H2SO4 according to Grasshoff et al. (1999). Carbon (C) and nitrogen (N) data were taken from Lüskow et al. (2021). P % DW (dry weight) decreased with size for Aequorea sp., Aurelia labiata, Cyanea capillata, and Salpa aspera (species with sufficient sample sizes). P % DW differed significantly for two development stages of the salp S. aspera. C/P and N/P were mostly size- and stage-independent. C/P values of GZ were generally higher than values of crustacean zooplankton.
    Keywords: 11_Midwater_trawl; 24_Bongo_net; 26_Midwater_trawl; 29_Midwater_trawl; 33_Midwater_trawl; 38_Midwater_trawl; 43_Midwater_trawl; 58_Midwater_trawl; 7_Dip_net; 7_Midwater_trawl; BA03_CanTrawl250; BA04_CanTrawl250; BONGO; Bongo net; Calculated; Carbon/Phosphorus ratio; CPE1_Dip_net; CS02_CanTrawl250; CS09_CanTrawl250; CS13_CanTrawl250; CS15_CanTrawl250; CS18_CanTrawl250; Ctenophore; DATE/TIME; DEPTH, water; Duration; Edwards Modulyo Freeze Dryer (Oakville, Ontario, CA); EP02_CanTrawl250; Event label; Gear; H02_CanTrawl250; Hand net; Heteropod; HN; Hope_Island_Dip_net; I_Midwater_trawl; IBC01_CanTrawl250; IBC03_CanTrawl250; IBC10_CanTrawl250; Identification; IVI10_CanTrawl250; IVI15_CanTrawl250; Jellyfish; JF03_CanTrawl250; Latitude of event; Life stage; LJS07_CanTrawl250; Location; Longitude of event; Measured using callipers; Methods of Seawater Analysis, Third Edition (Grasshoff et al., 1999); Midwater trawl; Month; MSN; Multiple opening/closing net; MWT; Nitrogen/Phosphorus ratio; Northeast Pacific; P12_Multinet_Medi; P26_Ring_net; Parameter; Phosphorus, total; QCSD01_CanTrawl250; QCSD02_CanTrawl250; QCSD04_CanTrawl250; QCST02_CanTrawl250; QCST05_CanTrawl250; QCST07_CanTrawl250; QCST11_CanTrawl250; QCST12_CanTrawl250; QCST19_CanTrawl250; RI01_CanTrawl250; RI05_CanTrawl250; Ring net; RN; Salish Sea; Salp; Sample type; Size; Sooke_Bay_Dip_net; Species; Station label; stoichiometry; Subarctic Northeast Pacific; T01_CanTrawl250; T02_CanTrawl250; T04_CanTrawl250; T06_CanTrawl250; T07_Dip_net; Tissue, dry mass; Vessel; VI_north_tip_Dip_net; VI02_CanTrawl250; VI03_CanTrawl250; VI04_CanTrawl250; VI07_CanTrawl250; VI08_CanTrawl250; VI09_CanTrawl250; VI12_CanTrawl250; VI14_CanTrawl250; VI22_CanTrawl250; VI25_Bongo_net; Weighted; Wet mass; Year of observation
    Type: Dataset
    Format: text/tab-separated-values, 1583 data points
    Location Call Number Limitation Availability
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  • 14
    Publication Date: 2024-04-25
    Description: Ocean acidification can negatively impact the early life-stages of marine fish, due to energetic costs incurred by the maintenance of acid–base homeostasis, leaving less energy available for growth and development. The embryos of intertidally spawning fishes, such as Pacific herring, are often air exposed for hours. We hypothesized that air exposure would be beneficial to the developing embryo due to a higher oxygen availability (and thus reduced metabolic costs to secure adequate oxygen) and permitting excess CO2 associated with ocean acidification to be off-gassed during emersion. To investigate this, we reared Pacific herring (Clupea pallasii) embryos under three tidal regimes (subtidal: fully immersed, low intertidal: 2 * 2 h air exposure, and high intertidal: 5 + 9 h air exposure) fully crossed with three aquatic CO2 levels (400, 1500 and 3200 µatm) at a water temperature of 9.5 °C and naturally fluctuating air temperature during air exposure. We measured the effects on embryonic development and hatch, as well as carry-over effects on larval development and survival. Air exposure during embryonic development had significant positive effects on growth, condition and survival in larval Pacific herring, with some interactive effects with CO2. Interestingly, CO2 by itself in the fully immersed treatment had no effect, but had significant interactions with air exposure. Our research suggests that air exposure during low tide can be highly beneficial to intertidally spawning fishes and needs to be taken into account in climate change studies and modeling.
    Keywords: Alkalinity, total; Animalia; Aragonite saturation state; Bicarbonate ion; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chordata; Clupea pallasii; Coast and continental shelf; Comment; Containers and aquaria (20-1000 L or 〈 1 m**2); Date; Development; Distance; Eggs; Eggs, diameter; Embryos; Fish larvae, length; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Heart rate; Identification; Individual dry mass; Laboratory experiment; Length; Mortality/Survival; Nekton; North Pacific; Number; OA-ICC; Ocean Acidification International Coordination Centre; Other studied parameter or process; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; Percentage; pH; Replicate; Reproduction; Salinity; Single species; Species, unique identification; Temperate; Temperature, water; Time in seconds; Time of day; Treatment; Type; Wet mass; Yolk sac area
    Type: Dataset
    Format: text/tab-separated-values, 73103 data points
    Location Call Number Limitation Availability
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  • 15
    Publication Date: 2021-05-19
    Description: Survival of larval Antarctic krill (Euphausia superba) during winter is largely dependent upon the presence of sea ice as it provides an important source of food and shelter. We hypothesized that sea ice provides additional benefits because it hosts fewer competitors and provides reduced predation risk for krill larvae than the water column. To test our hypothesis, zooplankton were sampled in the Weddell-Scotia Confluence Zone at the ice-water interface (0–2 m) and in the water column (0–500 m) during August–October 2013. Grazing by mesozooplankton, expressed as a percentage of the phytoplankton standing stock, was higher in the water column (1.97 ± 1.84%) than at the ice-water interface (0.08 ± 0.09%), due to a high abundance of pelagic copepods. Predation risk by carnivorous macrozooplankton, expressed as a percentage of the mesozooplankton standing stock, was significantly lower at the ice-water interface (0.83 ± 0.57%; main predators amphipods, siphonophores and ctenophores) than in the water column (4.72 ± 5.85%; main predators chaetognaths and medusae). These results emphasize the important role of sea ice as a suitable winter habitat for larval krill with fewer competitors and lower predation risk. These benefits should be taken into account when considering the response of Antarctic krill to projected declines in sea ice. Whether reduced sea-ice algal production may be compensated for by increased water column production remains unclear, but the shelter provided by sea ice would be significantly reduced or disappear, thus increasing the predation risk on krill larvae.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
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  • 16
    Publication Date: 2016-08-30
    Description: The condition and survival of Antarctic krill (Euphausia superba) strongly depends on sea ice conditions during winter. How krill utilize sea ice depends on several factors such as region and developmental stage. A comprehensive understanding of sea ice habitat use by krill, however, remains largely unknown. The aim of this study was to improve the understanding of the krill's interaction with the sea ice habitat during winter/early spring by conducting large-scale sampling of the ice-water interface (0-2 m) and comparing the size and developmental stage composition of krill with the pelagic population (0-500 m). Results show that the population in the northern Weddell Sea consisted mainly of krill that were less than one year old (age class 0; AC0), and that it was comprised of multiple cohorts. Size per developmental stage differed spatially, indicating that the krill likely were advected from various origins. The size distribution of krill differed between the two depth strata sampled. Larval stages with a relatively small size (mean 7 to 8 mm) dominated the upper two meter layer of the water column, while larger larvae and AC0 juveniles (mean 14 to 15 mm) were proportionally more abundant in the 0-500 m stratum. Our results show that, as krill mature, their vertical distribution and utilization of the sea ice appears to change gradually. This could be the result of changes in physiology and/or behaviour, as e.g. the krill's energy demand and swimming capacity increase with size and age. The degree of sea ice association will have an effect on large-scale spatial distribution patterns of AC0 krill and on predictions of the consequences of sea ice decline on their survival over winter.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 17
    Publication Date: 2018-01-03
    Description: A dominant Antarctic ecological paradigm suggests that winter sea ice is generally the main feeding ground for krill larvae. Observations from our winter cruise to the southwest Atlantic sector of the Southern Ocean contradict this view and present the first evidence that the pack-ice zone is a food-poor habitat for larval development. In contrast, the more open marginal ice zone provides a more favourable food environment for high larval krill growth rates. We found that complex under-ice habitats are, however, vital for larval krill when water column productivity is limited by light, by providing structures that offer protec- tion from predators and to collect organic material released from the ice. The larvae feed on this sparse ice-associated food during the day. After sunset, they migrate into the water below the ice (upper 20 m) and drift away from the ice areas where they have previously fed. Model analyses indicate that this behaviour increases both food uptake in a patchy food environment and the likelihood of overwinter transport to areas where feeding conditions are more favourable in spring.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 18
    Publication Date: 2019-07-16
    Description: The macrozooplankton and micronekton community of the Lazarev Sea (Southern Ocean) was investigated at 3 depth layers during austral summer, autumn and winter: (1) the surface layer (0–2 m); (2) the epipelagic layer (0–200 m); and (3) the deep layer (0–3000 m). Altogether, 132 species were identified. Species composition changed with depth from a euphausiid-dominated community in the surface layer, via a siphonophore-dominated community in the epipelagic layer, to a chaetognath-dominated community in the deep layer. The surface layer community predominantly changed along gradients of surface water temperature and sea ice parameters, whereas the epipelagic community mainly changed along hydrographical gradients. Although representing only 1% of the depth range of the epipelagic layer, mean per-area macrofauna densities in the surface layer ranged at 8% of corresponding epipelagic densities in summer, 6% in autumn, and 24% in winter. Seasonal shifts of these proportional densities in abundant species indicated different strategies in the use of the surface layer, including both hibernal downward and hibernal upward shift in the vertical distribution, as well as year-round surface layer use by Antarctic krill. These findings imply that the surface layer, especially when it is ice-covered, is an important functional node of the pelagic ecosystem that has been underestimated by conventional depth-integrated sampling in the past. The exposure of this key habitat to climate-driven forces most likely adds to the known susceptibility of Antarctic pelagic ecosystems to temperature rise and changing sea ice conditions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Format: application/pdf
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  • 19
    Publication Date: 2022-01-07
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 20
    Publication Date: 2022-07-20
    Description: In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass and abundance and their roles in maintaining food webs and ecosystem structure and function, including the provision of globally important ecosystem services. These groups are consumers of microbes, primary and secondary producers, and are prey for fishes, cephalopods, seabirds, and marine mammals. In providing the link between microbes, primary production, and higher trophic levels these taxa influence energy flows, biological production and biomass, biogeochemical cycles, carbon flux and food web interactions thereby modulating the structure and functioning of ecosystems. Additionally, Antarctic krill (Euphausia superba) and various fish species are harvested by international fisheries. Global and local drivers of change are expected to affect the dynamics of key zooplankton species, which may have potentially profound and wide-ranging implications for Southern Ocean ecosystems and the services they provide. Here we assess the current understanding of the dominant metazoan zooplankton within the Southern Ocean, including Antarctic krill and other key euphausiid, copepod, salp and pteropod species. We provide an overview of observed and potential future responses of these taxa to a changing Southern Ocean and the functional relationships by which drivers may impact them. To support future ecosystem assessments and conservation and management strategies, we also identify priorities for Southern Ocean zooplankton research.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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