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High abundances of small copepods early developmental stages and nauplii strengthen the perception of a non-dormant Arctic winter. Polar Biol 2022. [DOI: 10.1007/s00300-022-03025-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AbstractThe traditional view is that the Arctic polar night is a quiescent period for marine life, but recent reports of high levels of feeding and reproduction in both pelagic and benthic taxa have challenged this. We examined the zooplankton community present in Svalbard fjords, coastal waters, and the shelf break north of Svalbard, during the polar night. We focused on the population structure of abundant copepods (Calanus finmarchicus, Calanus glacialis, Metridia longa, Oithona similis, Pseudocalanus spp., Microcalanus spp., and Microsetella norvegica) sampled using 64-µm mesh nets. Numerically, copepod nauplii (≥ 50%) and the young developmental stages of small copepods (< 2 mm prosome length as adult) dominated the samples. Three main patterns were identified: (1) large Calanus spp. were predominantly older copepodids CIV–CV, while (2) the small harpacticoid M. norvegica were adults. (3) For other species, all copepodid stages were present. Older copepodids and adults dominated populations of O. similis, Pseudocalanus spp. and M. longa. In Microcalanus spp., high proportion of young copepodids CI–CIII indicated active winter recruitment. We discuss the notion of winter as a developing and reproductive period for small copepods in light of observed age structures, presence of nauplii, and previous knowledge about the species. Lower predation risks during winter may, in part, explain why this season could be beneficial as a period for development. Winter may be a key season for development of small, omnivorous copepods in the Arctic, whereas large copepods such as Calanus spp. seems to be reliant on spring and summer for reproduction and development.
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Balazy K, Boehnke R, Trudnowska E, Søreide JE, Błachowiak-Samołyk K. Phenology of Oithona similis demonstrates that ecological flexibility may be a winning trait in the warming Arctic. Sci Rep 2021; 11:18599. [PMID: 34545157 PMCID: PMC8452673 DOI: 10.1038/s41598-021-98068-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 09/01/2021] [Indexed: 11/20/2022] Open
Abstract
Rapidly warming Arctic is facing significant shifts in the zooplankton size-spectra manifested as increasing numbers of the small-sized copepod Oithona similis. Here we present a unique continuous data set covering 22 months, on its copepodite structure along with environmental drivers in the Atlantic-influenced high Arctic fjord Isfjorden (Spitsbergen). Abundance maxima of O. similis were observed in September when the highest seawater temperature was recorded. A high concentration of the indicator species of Atlantification Oithona atlantica was also observed at that time. The clear dominance of O. similis in the zooplankton community during the dark, theoretically unproductive season emphasizes its substantial role in sustaining a continuous carbon flow, when most of the large herbivorous copepods fall into sleeping state. The high sex ratio observed twice in both years during periods of high primary production suggests two main reproductive events per year. O. similis reproduced even in very low temperatures (< 0 °C) previously thought to limit their fecundity, which proves its unique thermal tolerance. Our study provides a new insight on ecology of this key copepod of marine ecosystems across the globe, and thus confirm the Climatic Variability Hypothesis assuming that natural selection favour species with such flexible adaptive traits as O. similis.
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Affiliation(s)
- Kaja Balazy
- Department of Marine Ecology, Institute of Oceanology, Polish Academy of Sciences, Powst. Warszawy 55, 81-712, Sopot, Poland.
| | - Rafał Boehnke
- Department of Marine Ecology, Institute of Oceanology, Polish Academy of Sciences, Powst. Warszawy 55, 81-712, Sopot, Poland
| | - Emilia Trudnowska
- Department of Marine Ecology, Institute of Oceanology, Polish Academy of Sciences, Powst. Warszawy 55, 81-712, Sopot, Poland
| | - Janne E Søreide
- Department of Arctic Biology, The University Centre in Svalbard (UNIS), PB 156, 9171, Longyearbyen, Norway
| | - Katarzyna Błachowiak-Samołyk
- Department of Marine Ecology, Institute of Oceanology, Polish Academy of Sciences, Powst. Warszawy 55, 81-712, Sopot, Poland
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Osvik RD, Ingebrigtsen RA, Norrbin MF, Andersen JH, Eilertsen HC, Hansen EH. Adding Zooplankton to the OSMAC Toolkit: Effect of Grazing Stress on the Metabolic Profile and Bioactivity of a Diatom. Mar Drugs 2021; 19:md19020087. [PMID: 33546196 PMCID: PMC7913365 DOI: 10.3390/md19020087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 01/28/2023] Open
Abstract
“One strain many compounds” (OSMAC) based approaches have been widely used in the search for bioactive compounds. Introducing stress factors like nutrient limitation, UV-light or cocultivation with competing organisms has successfully been used in prokaryote cultivation. It is known that diatom physiology is affected by changed cultivation conditions such as temperature, nutrient concentration and light conditions. Cocultivation, though, is less explored. Hence, we wanted to investigate whether grazing pressure can affect the metabolome of the marine diatom Porosira glacialis, and if the stress reaction could be detected as changes in bioactivity. P. glacialis cultures were mass cultivated in large volume bioreactor (6000 L), first as a monoculture and then as a coculture with live zooplankton. Extracts of the diatom biomass were screened in a selection of bioactivity assays: inhibition of biofilm formation, antibacterial and cell viability assay on human cells. Bioactivity was found in all bioassays performed. The viability assay towards normal lung fibroblasts revealed that P. glacialis had higher bioactivity when cocultivated with zooplankton than in monoculture. Cocultivation with diatoms had no noticeable effect on the activity against biofilm formation or bacterial growth. The metabolic profiles were analyzed showing the differences in diatom metabolomes between the two culture conditions. The experiment demonstrates that grazing stress affects the biochemistry of P. glacialis and thus represents a potential tool in the OSMAC toolkit.
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Affiliation(s)
- Renate Døving Osvik
- Marbio, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway; (J.H.A.); (E.H.H.)
- Microalgae and Microbiomes, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway; (R.A.I.); (H.C.E.)
- Correspondence: ; Tel.: +47-776-49-265
| | - Richard Andre Ingebrigtsen
- Microalgae and Microbiomes, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway; (R.A.I.); (H.C.E.)
| | - Maria Fredrika Norrbin
- Arctic Marine System Ecology, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway;
| | - Jeanette Hammer Andersen
- Marbio, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway; (J.H.A.); (E.H.H.)
| | - Hans Christian Eilertsen
- Microalgae and Microbiomes, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway; (R.A.I.); (H.C.E.)
| | - Espen Holst Hansen
- Marbio, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT–The Arctic University of Norway, N-9037 Tromsø, Norway; (J.H.A.); (E.H.H.)
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