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Year-round population dynamics of Limacina spp. early stages in a high-Arctic fjord (Adventfjorden, Svalbard)

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Abstract

The thecosome pteropods Limacina helicina and L. retroversa are important contributors to the zooplankton community in high-latitude environments but little is known about their distribution and life cycle under polar conditions. We collected the early life stages (< 1 mm) of the thecosome population in 2012 and 2013 at a bi-weekly to monthly resolution in fjord highly influenced by Arctic waters as well as Atlantic inflows (Adventfjorden, Svalbard, 78°N), together with environmental parameters. L. retroversa only occurred episodically, in association with the inflow of Atlantic water, with low numbers and random size distributions. This suggests that this boreal species does not fulfill its life cycle in Adventfjorden. In contrast, young specimens of L. helicina were present during the entire study. Veligers hatched in late summer/autumn and measured 0.14 mm on average. They grew with rates of 0.0006 mm day−1 over the 10–11 months of development. Only thereafter, growth accelerated by one order of magnitude and maximal rates were reached in autumn (0.0077 mm day−1). Our results indicate that L. helicina reaches a size of 1 mm after approximately 1.5 years in Adventfjorden. We therefore suggest that L. helicina overwinters the first year as a small juvenile and that it needs at least 2 years to reach an adult size of 5 mm in Adventfjorden. This reveals an complex and delicate aspect of the life-cycle of L. helicina and further research is needed to determine if it makes the population especially vulnerable towards climate changes.

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Fig. 1

(modified from Stübner et al. 2016)

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References

  • Accornero A, Manno C, Esposito F, Gambi MC (2003) The vertical flux of particulate matter in the polynya of Terra Nova Bay. Part II. Biological components. Ant Sci 15:175–188

    Article  Google Scholar 

  • Akima H, Gebhardt A, Petzold T. Akima (2020) Interpolation of Irregularly and Regularly Spaced Data. R package version 0.6-2.1. https://cran.r-project.org/web/packages/akima/index.html. Accessed 01 Mar 2021

  • Bathmann UV, Noji TT, von Bodungen B (1991) Sedimentation of pteropods in the Norwegian Sea in autumn. Deep Sea Res Part A 38:1341–1360

    Article  CAS  Google Scholar 

  • Bauerfeind E, Nöthig EM, Beszczynska A, Fahl K, Kaleschke L, Kreker K, Klages M, Soltwedel T, Lorenzen C, Wegner J (2009) Particle sedimentation patterns in the eastern Fram Strait during 2000–2005: results from the Arctic long-term observatory HAUSGARTEN. Deep Sea Res Part I 56:1471–1487

    Article  CAS  Google Scholar 

  • Bauerfeind E, Nöthig EM, Pauls B, Kraft A, Beszczynska-Möller A (2014) Variability in pteropod sedimentation and corresponding aragonite flux at the Arctic deep-sea long-term observatory HAUSGARTEN in the eastern Fram Strait from 2000 to 2009. J Marine Syst 132:95–105

    Article  Google Scholar 

  • Bé AWH, Gilmer RW (1977) A zoogeographic and taxonomic review of euthecosomatous pteropoda. Oceanic micropaleontology, 1st edn. Academic Press, London

    Google Scholar 

  • Bednaršek N, Tarling GA, Fielding S, Bakker DCE (2012) Population dynamics and biogeochemical significance of Limacina helicina antarctica in the Scotia Sea. DSR-II 59–60:105–116

    Google Scholar 

  • Bednaršek N, Tarling GA, Bakker DC, Fielding S, Feely RA (2014) Dissolution dominating calcification process in polar pteropods close to the point of aragonite undersaturation. PLoS ONE 9:1–14

    Article  CAS  Google Scholar 

  • Bernard KS, Froneman PW (2009) The sub-Antarctic euthecosome pteropod, Limacina retroversa: Distribution patterns and trophic role. Deep Sea Res Part I 56:582–598

    Article  CAS  Google Scholar 

  • Berner RA, Honjo S (1981) Pelagic sedimentation of aragonite: its geochemical significance. Science 211:940–942

    Article  CAS  PubMed  Google Scholar 

  • Beszczynska-Möller A, Fahrbach E, Schauer U, Hansen E (2012) Variability of Atlantic water temperature and transport in the entrance to the Arctic Ocean in 1997–2010. ICES J Mar Sci 69:852–863

    Article  Google Scholar 

  • Blachowiak-Samolyk K, Søreide JE, Kwasniewski S, Sundfjord A, Hop H, Falk-Petersen S, Hegseth EN (2008) Hydrodynamic control of mesozooplankton abundance and biomass in northern Svalbard waters (79–81 N). Deep Sea Res Part II 55:2210–2224

    Article  CAS  Google Scholar 

  • Böer M, Graeve M, Kattner G (2006) Impact of feeding and starvation on the lipid metabolism of the Arctic pteropod Clione limacina. J Exp Mar Biol Ecol 328:98–112

    Article  CAS  Google Scholar 

  • Boissonnot L, Niehoff B, Ehrenfels B, Søreide JE, Hagen W, Graeve M (2019) Lipid and fatty acid turnover of the pteropods Limacina helicina, L. retroversa and Clione limacina from Svalbard waters. Mar Ecol Progr Ser 609:133–149

    Article  CAS  Google Scholar 

  • Botev ZI, Grotowski JF, Kroese DP (2010) Kernel density estimation via diffusion. Ann Stat 38:2916–2957

    Article  Google Scholar 

  • Buitenhuis ET, Le Quere C, Bednaršek N, Schiebel R (2019) Large contribution of Pteropods to shallow CaCO3 export. Global Biogeochem Cycles 33(3):458–468

    Article  CAS  Google Scholar 

  • Byrne RH, Acker JG, Betzer PR, Feely RA (1984) Water column dissolution of aragonite. Nature 312:321–326

    Article  CAS  Google Scholar 

  • Chen C, Bé AW (1964) Seasonal distributions of euthecosomatous pteropods in the surface waters of five stations in the Western North Atlantic. Bull Mar Sci 14:185–220

    Google Scholar 

  • Colgan DJ, Ponder WF, Eggler PE (2000) Gastropod evolutionary rates and phylogenetic relationships assessed using partial rDNA and histone H3 sequences. Zool Scri 29:29–63

    Article  Google Scholar 

  • Comeau S, Gorsky G, Jeffree R, Teyssié JL, Gattuso JP (2009) Impact of ocean acidification on a key Arctic pelagic mollusc (Limacina helicina). Biogeosc 6:1877–1882

    Article  CAS  Google Scholar 

  • Comeau S, Jeffree R, Teyssié J-L, Gattuso J-P, Stepanova A (2010) Response of the arctic pteropod limacina helicina to projected future environmental conditions. PLoS ONE 5(6):e11362. https://doi.org/10.1371/journal.pone.0011362

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  • Comeau S, Alliouane S, Gattuso JP (2012) Effects of ocean acidification on overwintering juvenile Arctic pteropods Limacina helicina. Mar Ecol Prog Ser 456:279–284

    Article  CAS  Google Scholar 

  • Conover RJ, Lalli CM (1972) Feeding and growth in Clione limacina (Phipps), a pteropod mollusc. J Exp Mar Biol Ecol 9:279–302

    Article  Google Scholar 

  • Cottier FR, Nilsen F, Skogseth R, Tverberg V, Skarðhamar J, Svendsen H (2010) Arctic fjords: a review of the oceanographic environment and dominant physical processes. Geol Soc Spec Publ 344(1):35–50

    Article  Google Scholar 

  • Dadon JR (1990) Annual cycle of Limacina retroversa in Patagonian waters. Ame Malacol Bull 8:77–84

    Google Scholar 

  • Dadon JR, de Cidre LL (1992) The reproductive cycle of the Thecosomatous pteropod Limacina retroversa in the western South Atlantic. Mar Biol 114:439–442

    Article  Google Scholar 

  • Gannefors C, Böer M, Kattner G, Graeve M, Eiane K, Gulliksen B et al (2005) The Arctic sea butterfly Limacina helicina: lipids and life strategy. Mar Biol 147:169–177

    Article  Google Scholar 

  • Gilmer RW, Harbison GR (1991) Diet of Limacina helicina (Gastropoda: Thecosomata) in Arctic waters in midsummer. Mar Ecol Prog Ser 77:125–134

    Article  Google Scholar 

  • Hagen W, Auel H (2001) Seasonal adaptations and the role of lipids in oceanic zooplankton. Zoology 104:313–326

    Article  CAS  PubMed  Google Scholar 

  • Harbison GR, Gilmer RW (1986) Effects of animal behaviour on sediment trap collections: implications for the calculation of aragonite fluxes. Deep Sea Res A 33:1017–1024

    Article  CAS  Google Scholar 

  • Hop H, Falk-Petersen S, Svendsen H, Kwasniewski S, Pavlov V, Pavlova O, Søreide JE (2006) Physical and biological characteristics of the pelagic system across Fram Strait to Kongsfjorden. Prog Oceanogr 71:182–231

    Article  Google Scholar 

  • Hopkins TL (1985) Food web of an Antarctic midwater ecosystem. Mar Biol 89:197–212

    Article  Google Scholar 

  • Hopkins TL (1987) Midwater food web in McMurdo Sound, Ross Sea, Antarctica. Mar Biol 96:93–106

    Article  Google Scholar 

  • Hopkins TL, Torres JJ (1989) Midwater food web in the vicinity of a marginal ice zone in the western Weddell Sea. Deep Sea Res Part A 36:543–560

    Article  Google Scholar 

  • Howes EL, Bednaršek N, Büdenbender J, Comeau S, Doubleday A, Gallager SM, Hopcroft RR, Lischka S, Maas AE, Bijma J, Gattuso JP (2014) Sink and swim: a status review of thecosome pteropod culture techniques. J Plankton Res 36:299–315

    Article  CAS  Google Scholar 

  • Howes EL, Stemmann L, Assailly C, Irisson JO, Dima M, Bijma J, Gattuso JP (2015) Pteropod time series from the North Western Mediterranean (1967–2003): impacts of pH and climate variability. Mar Ecol Prog Ser 531:193–206

    Article  CAS  Google Scholar 

  • Hsiao SC (1939) The reproductive system and spermatogenesis of Limacina (Spiratella) retroversa (Flem.). Biol Bull 76:7–25

    Article  Google Scholar 

  • Hunt BPV, Pakhomov EA, Hosie GW, Siegel V, Ward P, Bernard K (2008) Pteropods in southern ocean ecosystems. Prog Oceanogr 78:193–221

    Article  Google Scholar 

  • Husson F, Josse J (2010) missMDA: handling missing values with/in multivariate data analysis (principal component methods). R package version 1.2. http://www.agrocampus-ouest.fr/math/husson. Accessed 17 August 2016

  • IPCC (2019) Special Report on the Ocean and Cryosphere in a Changing Climate. Pörtner HO, Roberts DC, Masson-Delmotte V, Zhai P, Tignor M, Poloczanska E, Mintenbeck K, Alegría A, Nicolai M, Okem A, Petzold J, Rama B, Weyer NM (eds.). In press

  • Katoh K, Asimenos G, Toh H (2009) Multiple alignment of DNA sequences with MAFFT. Methods Mol Biol 537:39–64

    Article  CAS  PubMed  Google Scholar 

  • Kattner G, Hagen W, Graeve M, Albers C (1998) Exceptional lipids and fatty acids in the pteropod Clione limacina (Gastropoda) from both polar oceans. Mar Chem 61:219–228

    Article  CAS  Google Scholar 

  • Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A, Markowitz S, Duran C, Thierer T, Ashton B, Mentjies P, Drummond A (2012) Geneious Basic: an integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics 28:1647–1649

    Article  PubMed  PubMed Central  Google Scholar 

  • Knebelsberger T, Stöger I (2012) DNA extraction, preservation, and amplification. In: Kress WJ, Erickson DL (eds) DNA barcodes: methods and protocols. Humana Press, Totowa, pp 311–338

    Chapter  Google Scholar 

  • Kobayashi HA (1974) Growth cycle and related vertical distribution of the thecosomatous pteropod Spiratella (“Limacina”) helicina in the central Arctic Ocean. Mar Biol 26:295–301

    Article  Google Scholar 

  • Lalli CM, Gilmer RW (1989) Pelagic snails: the biology of holoplanktonic gastropod mollusks. Stanford University Press, Stanford

    Book  Google Scholar 

  • Lalli CM, Wells FE (1978) Reproduction in genus Limacina (Opisthobranchia: Thecosomata). J Zool 186:95–108

    Article  Google Scholar 

  • Lancraft TM, Hopkins TL, Torres JJ, Donnelly J (1991) Oceanic micronektonic/macrozooplanktonic community structure and feeding in ice covered Antarctic waters during the winter (AMERIEZ 1988). Polar Biol 11:157–167

    Article  Google Scholar 

  • Lê S, Josse J, Husson F (2008) FactoMineR: an R package for multivariate analysis. J Stat Softw 25:1–18

    Article  Google Scholar 

  • Lebour MV (1932) Limacina retroversa in Plymouth Waters. J Mar Biol Assoc UK 18:123–126

    Article  Google Scholar 

  • Leikvin Ø, Evenset A (2009) Avløp fra Longyearbyen til Adventfjorden. Miljøfaglige vurderinger. Akvaplan-Niva report, Trosmø

  • Lischka S, Riebesell U (2012) Synergistic effects of ocean acidification and warming on overwintering pteropods in the Arctic. Glob Change Biol 18:3517–3528

    Article  Google Scholar 

  • Lischka S, Büdenbender J, Boxhammer T, Riebesell U (2011) Impact of ocean acidification and elevated temperatures on early juveniles of the polar shelled pteropod Limacina helicina: mortality, shell degradation, and shell growth. Biogeosciences 8:8178–8214

    Article  CAS  Google Scholar 

  • Maas AE, Elder LE, Dierssen HM, Seibel BA (2011) Metabolic response of Antarctic pteropods (Mollusca: Gastropoda) to food deprivation and regional productivity. Mar Ecol Prog Ser 441:129–139

    Article  CAS  Google Scholar 

  • Macdonald P, Du J (2018) Mixdist: finite mixture distribution models. R package version 0.5-5. http://cran.r-project.org/web/packages/mixdist/index.html. Accessed 01 Mar 2021

  • Manno C, Tirelli V, Accornero A, Fonda Umani S (2010) Importance of the contribution of Limacina helicina faecal pellets to the carbon pump in Terra Nova Bay (Antarctica). J Plankton Res 32:145–152

    Article  Google Scholar 

  • Manno C, Morata N, Primicerio R (2012) Limacina retroversa’s response to combined effects of ocean acidification and sea water freshening. Estuar Coast Shelf Sci 113:163–171

    Article  CAS  Google Scholar 

  • Marquardt M, Vader A, Stubner EI, Reigstad M, Gabrielsen TM (2016) Strong seasonality of marine microbial eukaryotes in a high-arctic fjord (Isfjorden, in West Spitsbergen, Norway). Appl Environ Microbiol 82:1868–1880

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  • Meinecke G, Wefer G (1990) Seasonal pteropod sedimentation in the Norwegian Sea. Palaeogeogr Palaeoclimatol Palaeoecol 79:129–147

    Article  Google Scholar 

  • Morton JE (1954) The biology of Limacina retroversa. J Mar Biol Assoc UK 33:297–312

    Article  Google Scholar 

  • Nilsen F, Cottier F, Skogseth R, Mattsson S (2008) Fjord–shelf exchanges controlled by ice and brine production: the interannual variation of Atlantic Water in Isfjorden, Svalbard. Cont Shelf Res 28(14):1838–1853

    Article  Google Scholar 

  • Noji TT, Bathmann UV, von Bodungen B, Voss M, Antia A, Krumbholz M et al (1997) Clearance of picoplankton-sized partides and formation of rapidly sinking aggregates by the pteropod, Limacina retroversa. J Plankton Res 19:863–875

    Article  Google Scholar 

  • Orr JC, Fabry VJ, Aumont O, Bopp L, Doney SC, Feely RA, Gnanadesikan A, Gruber N, Ishida A, Joos F, Key RM (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437:681–686

    Article  CAS  PubMed  Google Scholar 

  • Perissinotto R (1992) Mesozooplankton size-selectivity and grazing impact on the phytoplankton community of the Prince Edward Archipelago (Southern Ocean). Mar Ecol Prog Ser 79:243–258

    Article  Google Scholar 

  • R Core Team (2019) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna

    Google Scholar 

  • Redfield AC (1939) The history of a population of Limacina retroversa during its drift across the Gulf of Maine. Biol Bull 76:26–47

    Article  Google Scholar 

  • Schauer U, Beszczynska-Möller A, Walczowski W, Fahrbach E, Piechura J, Hansen E (2008) Variation of measured heat flow through the Fram Strait between 1997 and 2006. In: Dickson RR, Meincke J, Rhines P (eds) Arctic-Subarctic Ocean Fluxes: defining the role of the Northern Seas in Climate. Springer, Dordrecht, pp 65–85

    Chapter  Google Scholar 

  • Spielhagen RF, Werner K, Sørensen SA, Zamelczyk K, Kandiano E, Budeus G, Husum K, Marchitto TM, Hald M (2011) Enhanced modern heat transfer to the Arctic by warm Atlantic water. Science 33(6016):450–453

    Article  CAS  Google Scholar 

  • Stübner EI, Søreide JE, Reigstad M, Marquardt M, Blachowiak-Samolyk K (2016) Year-round meroplankton dynamics in high-Arctic Svalbard. J Plankton Res 38(3):522–536

    Article  Google Scholar 

  • Svendsen H, Beszczynska-Møller A, Hagen JO, Lefauconnier B, Tverberg V, Gerland S, Ørbøk JB, Bischof K, Papucci C, Zajączkowski M, Azzolini R (2002) The physical environment of Kongsfjorden—Krossfjorden, an Arctic fjord system in Svalbard. Polar Res 21:133–166

    Google Scholar 

  • Tsurumi M, Mackas DL, Whitney FA, DiBacco C, Galbraith MD, Wong CS (2005) Pteropods, eddies, carbon flux, and climate variability in the Alaska Gyre. Deep Sea Res Part II 52:1037–1053

    Article  CAS  Google Scholar 

  • Vader A, Marquardt M, Meshram AR, Gabrielsen TM (2015) Key Arctic phototrophs are widespread in the polar night. Pol Biol 38:13–21

    Article  Google Scholar 

  • van der Spoel S (1967) Euthecosomata: A group with remarkable developmental stages (Gastropoda, Pteropoda). Zoological Museum, Amsterdam

    Google Scholar 

  • van der Spoel S, Dadon JR (1999) Pteropoda. In: Boltovskoy D (ed) South Atlantic zooplankton. Backhhuys, Leiden

    Google Scholar 

  • Walkusz W, Kwasniewski S, Falk-Petersen S, Hop H, Tverberg V, Wieczorek P, Węsławski JM (2009) Seasonal and spatial changes in the zooplankton community of Kongsfjorden, Svalbard. Polar Res 28:254–281

    Article  Google Scholar 

  • Wang K, Hunt BP, Liang C, Pauly D, Pakhomov EA (2017) Reassessment of the life cycle of the pteropod Limacina helicina from a high resolution interannual time series in the temperate North Pacific. ICES J Mar Sci 74(7):1906–1920

    Article  Google Scholar 

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Acknowledgements

The research presented herein was part of L.B.’s PhD thesis at Bremen University in 2017. We are grateful for the UNIS logistical support in field, to Prof. Tove M. Gabrielsen for inviting us to take part in her IsA time series field campaign and Dr. Anna Vader and Dr. Miriam Marquardt for sharing chlorophyll a data. Thanks go to the logistic team of UNIS for their excellent support in Longyearbyen and during the field campaigns of 2012 and 2013. Many thanks go to Silke Lischka, who provided additional samples for genetic examination. The study was partially funded by the Research Council of Norway (Arctic Field Grant, Svalbard Science Forum, project ID 235913/E10 and CLEOPATRA II, project ID 216537/E10) and the Helmholtz Graduate School for Polar and Marine Research. DNA extraction and sequencing was funded by the DFG grant to P.D. Dr.Michael Schroedl (DFG SCHR667/15-1). We would like to thank Silke Lischka, Brian P.V. Hunt and one additional anonymous referee for their valuable reviews, which helped to considerably improve the quality of the manuscript.

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Authors and Affiliations

  1. Alfred-Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany

    Lauris Boissonnot, Martin Graeve & Barbara Niehoff

  2. Aqua Kompetanse AS, Havbruksparken, Storlavika 7, 7770, Flatanger, Norway

    Lauris Boissonnot

  3. University Centre in Svalbard, N-9171, Longyearbyen, Norway

    Lauris Boissonnot, Janne E. Søreide & Eike Stübner

  4. SNSB Bavarian State Collection of Zoology, Section Mollusca, Münchhausenstr. 21, 81247, Munich, Germany

    Peter Kohnert & Michael Schrödl

  5. Department Biologie II, Biozentrum, Ludwig-Maximilians-Universität, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany

    Peter Kohnert & Michael Schrödl

  6. Department Surface Waters—Research and Management, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Kastanienbaum, Switzerland

    Benedikt Ehrenfels

  7. Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland

    Benedikt Ehrenfels

  8. Center of Geobiology and Biodiversity Research, Ludwig-Maximilians-Universität, Richard-Wagner-Str. 10, 80333, Munich, Germany

    Michael Schrödl

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  1. Lauris Boissonnot
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Contributions

LB, JES and BN conceived the study based on field observations performed by JES and ES on the entire mesozooplankton community. PK performed molecular analyses with the help of MS and wrote the corresponding section of material and methods. LB analyzed the pteropod distribution as well as the meteorological data, with help of BN, MG and JES. LB, BE and BN interpreted the data, wrote the manuscript and revised it. All authors read and approved the manuscript.

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Boissonnot, L., Kohnert, P., Ehrenfels, B. et al. Year-round population dynamics of Limacina spp. early stages in a high-Arctic fjord (Adventfjorden, Svalbard). Polar Biol 44, 1605–1618 (2021). https://doi.org/10.1007/s00300-021-02904-6

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