Seasonal variation in the diversity and abundance of pelagic larvae of Antarctic marine invertebrates

Most marine benthic macroinvertebrate species reproduce via a larval phase but attempts to explain the occurrence of different larval strategies (feeding or non-feeding, pelagic or benthic) in different habitats have been largely inconclusive. There have been very few year-round surveys of meroplankton at any latitude and in consequence fundamental data on the diversity, abundance, and timings of larval life history phases are lacking. There has been considerable debate regarding the viability of pelagic larvae in cold waters with highly seasonal primary production but there has been only one year-round study of meroplankton in the Southern Ocean, and that was outside of the Antarctic Circle. We present data from the first year-round survey of meroplankton assemblages at a location within the Antarctic Circle. We surveyed abundances of meroplanktonic larvae over 1.5 year at Rothera Point, West Antarctic Peninsula (67°34′S, 68°07′W). Larvae were collected in monthly diver-towed net samples close to the seabed at 20 and 6 m total water depths at each of three locations and were identified and counted live immediately after sampling. A total of 99 operationally defined taxonomic types representing 11 phyla were recorded but this is likely to be an underestimate of true diversity because of inherent difficulties of identification. Larvae were present in all months of the year and although planktotrophic larvae were more abundant in summer, both feeding and non-feeding types were present in all months. Comparisons of seasonal larval abundances with data from a settlement study at the same sites and from the literature show that larvae of mobile adults settle in summer regardless of developmental type, whereas sessile taxa settle in all seasons. We suggest that this is a consequence of differences in the food requirements of mobile and sessile fauna and that the availability of food for post-larval juveniles is more critical for survival than factors affecting the larval stage itself.

[1]  J. Pearse,et al.  Reproduction of Antarctic Benthic Marine Invertebrates: Tempos, Modes, and Timing , 1991 .

[2]  D. Bowden.  Quantitative characterization of shallow marine benthic assemblages at Ryder Bay, Adelaide Island, Antarctica , 2005 .

[3]  L. W. Wood.  Chloroform–Methanol Extraction of Chlorophyll a , 1985 .

[4]  A. Reitzel,et al.  Relationships between spawning date and larval development time for benthic marine invertebrates: a modeling approach , 2004 .

[5]  D. Stanwell-Smith,et al.  The Timing of reproduction in the Antarctic limpet Nacella concinna (srebel, 1908) (Patellidae) at Signy Island, in relation to environmental variables , 1998 .

[6]  L. Peck,et al.  Metabolism and development of pelagic larvae of Antarctic gastropods with mixed reproductive strategies , 2006 .

[7]  P. Tyler,et al.  Multi-year observations on the gametogenic ecology of the Antarctic seastar Odontaster validus , 2007 .

[8]  T. Brand.  Trophic interactions and community ecology of the shallow-water marine benthos along the Antarctic Peninsula , 1980 .

[9]  Paul A. Tyler,et al.  Long-term interannual cycles of the gametogenic ecology of the Antarctic brittle star Ophionotus victoriae , 2004 .

[10]  R. Vance.  On Reproductive Strategies in Marine Benthic Invertebrates , 1973, The American Naturalist.

[11]  E. Poulin,et al.  Combined ecological factors permit classification of developmental patterns in benthic marine invertebrates: a discussion note. , 2001, Journal of experimental marine biology and ecology.

[12]  G. Thorson.  REPRODUCTIVE and LARVAL ECOLOGY OF MARINE BOTTOM INVERTEBRATES , 1950, Biological reviews of the Cambridge Philosophical Society.

[13]  C. Todd,et al.  Reproductive Strategies of Marine Benthic Invertebrates: A Settlement-Timing Hypothesis , 1981 .

[14]  C. Young,et al.  Atlas of Marine Invertebrate Larvae , 2003 .

[15]  A. Clarke,et al.  The ecology of an assemblage dominant: the encrusting bryozoan Fenestrulina rugula , 1998 .

[16]  A. Underwood.  On Models for Reproductive Strategy in Marine Benthic Invertebrates , 1974, The American Naturalist.

[17]  L. Peck,et al.  Feast and famine in Antarctica: seasonal physiology in the limpet Nacella concinna , 2002 .

[18]  L. Peck,et al.  Distribution of pelagic larvae of benthic marine invertebrates in the Bellingshausen Sea , 1995, Polar Biology.

[19]  A. Clarke,et al.  The seasonal cycle of phytoplankton, macronutrients, and the microbial community in a nearshore Antarctic marine ecosystem , 1996 .

[20]  L. Peck,et al.  The distribution, abundance and seasonality of pelagic marine invertebrate larvae in the maritime Antarctic , 1999 .

[21]  J. Pearse,et al.  Bacterivory: A Novel Feeding Mode for Asteroid Larvae , 1986, Science.

[22]  R. R. Strathmann.  Feeding and Nonfeeding Larval Development and Life-History Evolution in Marine Invertebrates , 1985 .

[23]  L. Grange.  Reproductive success in Antarctic marine invertebrates , 2004 .

[24]  D. Stanwell-Smith,et al.  Seasonality of reproduction in the cushion star Odontaster validus at Signy Island, Antarctica , 1998 .

[25]  I. Bosch,et al.  Pre-feeding embryos of antarctic and temperate echinoderms use dissolved organic material for growth and metabolic needs , 1994 .

[26]  A. Clarke,et al.  Seasonality of feeding activity in Antarctic suspension feeders , 1995, Polar Biology.

[27]  S. Miller,et al.  Smithsonian at the poles : contributions to International Polar Year science , 2009 .

[28]  O. Hoegh‐Guldberg,et al.  Temperature, Food Availability, and the Development of Marine Invertebrate Larvae , 1995 .

[29]  J. Pearse,et al.  Reproduction in cold water: paradigm changes in the 20th century and a role for cidaroid sea urchins , 2004 .

[30]  K. R. Clarke,et al.  Change in marine communities : an approach to statistical analysis and interpretation , 2001 .

[31]  L. Peck,et al.  Antarctic sessile marine benthos: colonisation and growth on artificial substrata over three years , 2006 .

[32]  I. Fetzer,et al.  Reproductive strategies of benthic invertebrates in the Kara Sea (Russian Arctic): adaptation of reproduction modes to cold water , 2008 .

[33]  M. Sewell.  Examination of the meroplankton community in the south-western Ross Sea, Antarctica, using a collapsible plankton net , 2004, Polar Biology.

[34]  J. Seager.  Reproductive biology of the antarctic opisthobranch Philine gibba Strebel , 1979 .

[35]  M. Clark,et al.  DNA barcoding: a molecular tool to identify Antarctic marine larvae , 2006 .

[36]  L. Mcedward.  Reproductive Strategies of Marine Benthic Invertebrates Revisited: Facultative Feeding by Planktotrophic Larvae , 1997, The American Naturalist.

[37]  J. Pearse,et al.  DEVELOPMENT, METAMORPHOSIS, AND SEASONAL ABUNDANCE OF EMBRYOS AND LARVAE OF THE ANTARCTIC SEA URCHIN STERECHINUS NEUMAYERI. , 1987, The Biological bulletin.

[38]  L. Peck.  Larval development in the Antarctic nemertean Parborlasia corrugatus (Heteronemertea: Lineidae) , 1993 .

[39]  D. Manahan,et al.  Cost of Protein Synthesis and Energy Allocation During Development of Antarctic Sea Urchin Embryos and Larvae , 2007, The Biological Bulletin.

[40]  C. Gallardo,et al.  Hatching mode and latitude in marine gastropods: revisiting Thorson's paradigm in the southern hemisphere , 2001 .

[41]  A. Clarke,et al.  Seasonality of feeding and nutritional status during the austral winter in the Antarctic sea urchin Sterechinus neumayeri , 2001 .

[42]  D. Jablonski,et al.  LARVAL ECOLOGY OF MARINE BENTHIC INVERTEBRATES: PALEOBIOLOGICAL IMPLICATIONS , 1983 .

[43]  J. Pechenik.  On the advantages and disadvantages of larval stages in benthic marine invertebrate life cycles , 1999 .

[44]  S. A. Mileikovsky.  Types of larval development in marine bottom invertebrates, their distribution and ecological significance: a re-evaluation , 1971 .

[45]  L. Mcedward.  Ecology of Marine Invertebrate Larvae , 1995 .

[46]  S. Brockington.  The seasonal ecology and physiology of Sterechinus neumayeri (Echinodermata: Echinoidea) at Adelaide Island, Antarctica , 2001 .

[47]  P. Tyler,et al.  Seasonal variation in the gametogenic ecology of the Antarctic scallop Adamussium colbecki , 2003, Polar Biology.

[48]  J. Pearse,et al.  Developmental types of shallow-water asteroids of McMurdo Sound, Antarctica , 1990 .

[49]  John Grahame,et al.  Reproductive patterns of marine invertebrates , 1985 .

[50]  P. Tyler,et al.  Very slow development in two Antarctic bivalve molluscs, the infaunal clam Laternula elliptica and the scallop Adamussium colbecki , 2007 .

[51]  R. Mooi,et al.  Brooding and Species Diversity in the Southern Ocean: Selection for Brooders Or Speciation within Brooding Clades? , 2009 .

[52]  D. Bowden.  Seasonality of recruitment in Antarctic sessile marine benthos , 2005 .