MEPS 192:173-180 (2000)  -  doi:10.3354/meps192173

Temperature and pressure tolerances of embryos and larvae of the Antarctic sea urchin Sterechinus neumayeri (Echinodermata: Echinoidea): potential for deep-sea invasion from high latitudes

Paul A. Tyler1,*, Craig M. Young2, Andrew Clarke3

1School of Ocean and Earth Science, University of Southampton, SOC, Southampton SO14 3Z, United Kingdom
2Department of Larval Ecology, Harbor Branch Oceanographic Institution, 5600 US 1 N, Ft. Pierce, Florida 34946, USA
3British Antarctic Survey, High Cross Madingley Road, Cambridge CB3 0ET, United Kingdom

ABSTRACT: Early embryos, blastulae, prisms and 4-arm plutei of the Antarctic shallow-water echinoid Sterechinus neumayeri were subjected to a temperature/pressure regime from -1.2 to +2.5°C and from 1 to 250 atm. Early embryos were able to tolerate pressures up to 150 atm at +2.5 to +0.9°C and 100 atm at -1.2°C. Blastulae and prisms showed an increasing sensitivity to pressure with decreasing temperature. Four-arm plutei were more sensitive than early larval stages to pressure and were also more sensitive to pressure at lower temperatures. These data suggest that the embryonic and larval stages of S. neumayeri are capable of surviving low temperatures in surface waters, but only tolerate higher pressures when water column temperatures are >0°C. Such a pattern of temperature increase is seen in the formation of Antarctic Bottom Water in the Weddell Sea and we infer that the larvae of S. neumayeri are capable of penetrating the deep sea through the agency of this deep water formation.


KEY WORDS: Sterechinus · Antarctica · Deep sea · Larvae · Pressure · Temperature


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