Ecology of the Antarctic bivalve Laternula elliptica (King and Broderip) in Collins Harbor, King George Island: Benthic environment and an adaptive strategy

• Main Author: In-Young Ahn
• Format: Report
• Language: English
• Published: Polar Research Center, Korea Ocean Research and Development Institute 1994
• Subjects: Antarctic; Laternula elliptica; ice impacts; distribution; density; sediment; The Antarctic; King George Island; Rocky Beach; Collins Harbor; Antarc*; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2257; http://id.nii.ac.jp/1291/00002257/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2257&item_no=1&attribute_id=18&file_no=1

The Antarctic lamellibranch Laternula elliptica occurs commonly in shallow waters around the Antarctic Continent and islands. Physical and chemical characteristics of the bottom environment of a representative habitat were investigated to understand the successful adaptation of this species in the Antarctic nearshore waters. A high density of L. elliptica (average 87ind. m^<-2>, approx. 9kg m^<-2>) occurred at 25-30m water depth of Collins Harbor, a sheltered bay with a wide area of exposed rocky beach during summer time. Bottom substrate was sandy mud mixed with gravel particles. Sedimentary organic carbon content was very low (0.2-0.8%) apparently due to massive land runoff during summer months. Carbon value was relatively high (1.23%) in surface flocculent ooze which consisted almost entirely of benthic diatoms and organic aggregates, indicating a tight coupling of benthic primary production and a rapid and complete utilization of organic matter by benthic animals. L. elliptica was not found at depths less than 5m (pebble zone), indicating that physical instability due to ice abrasion may be a factor determining the upper limit of vertical distribution of this species. Deep-burrowing seems to be primarily a means for avoiding ice impacts. A pair of stout and highly extendable siphons appear to be a morphological feature to feed in the ice-scoured substrate while staying deep in the sediment. The present study suggests that a trade-off between increasing physical stability and decreasing food input with depth may determine both the depth range of vertical distribution and the magnitude of Laternula elliptica biomass.