Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: A comparison of physiological and morphologlical adaptations between the bay isopod Idotea resecata and the open-coast isopod Idotea montereyensis
Student Author(s): Atkin, David
Faculty Advisor(s): Lee, Welton
Pages: 29
Location: Final Papers Biology 175H
Date: June 1973
Keywords: Isopoda
Abstract: Idotea resecata lives primarily on bay Zostera and Macrocystis and is considered to a typical bay species (Menzies,1950). Idotea montereyensis is adapted to open coast Phyllospadix beds and is considered to be a typical open coast species. Both species have been labelled as lower intertidal forms. Tolerances to heat, salinity, and survival at low oxygen tensions were measured, and morphology of the pereaopods was also examined. It was found that I. montereyensis had longer LT-50's for the higher temperature and salinity stresses, enabling it to cope with both the lower intertidal environment of the Phyllospadix beds and also the higher intertidal tide pools into which it is sometimes washed. I. resecata has slightly greater abilities to deal with low oxygen situations, enabling it to cope with the low oxygen concentrations often found in Zostera beds. The pereaopods of I. montereyensis seem to be more adapted than those of I. resecata to gripping the substrate effectively in heavy wave action on the basis of morphology. Beacause I. montereyensis migrates vertically as it develops and has the physiological tolerances to cope with the range of environmental parameters associated with such a migration, it is felt that to consider it only a species of the lower intertidal is misleading.