Intertidal gastropods

Antipredator Responses by Intertidal Gastropods to Chemicals from Starfish... 

Bullock TH (1953) Predator recognition and escape responses of some intertidal gastropods on presence of starfish. Behaviour 5 130-140... 

Gastropods (snails), echinoderms (sea urchins and sea stars) and annelids (lugworms) were exposed to oil saturated sediments and assayed for AHH activity (17). Sediment was mixed with Venezuelan crude at a concentration of 0.2-0.5% and exposures were for one week (4°C) in a static system with water renewal at 2-3 day intervals. The aim was to determine if oil soaked sediments could induce AHH activity in some representative intertidal benthic organisms common to the subarctic waters of the North West Atlantic. Digestive gland homogenates from snails, sea urchins, and sea stars and a combination of intestinal and gill tissues from annelids were used in the enzyme assays. 

Unlike gastropods, which have one shell or lack shells completely, bivalves are mollusks that possess two shells. Bivalve shells, or valves, hinge together on one side and are opened and closed by strong muscles. Clams, mussels, scallops, and oysters are some of the many types of bivalves found in the intertidal zone. 

Mollusks commonly found in the intertidal zone include bivalves and gastropods. Bivalves are soft-bodied animals that are protected by two strong shells. Their bodies are covered by a delicate tissue, the mande, which secretes the shell and defensive chemicals. Most are filter feeders that trap small bits of food in the mucus on their gills. Clams, mussels, and oysters are examples of coastal bivalves. 

McQuaid, C. D., and Scherman, P. A. 1988. Thermal stress in a high shore intertidal environment Morphological and behavioural adaptations of the gastropod Littorina africana. In G. Chelazzi and M. Vannini (eds.) Behavioral Adaptation to Intertidal Life. New York Plenum Press, pp. 213-224. 

Nagata [113] determined the energy transformation in an intertidal population of three gastropods (snails) which formed the more pronounced part of biomass and density in this habitat. Respiration and combustion measurements exhibited highly different contributions from 27,6 to 496 kJ/mVyear of these herbivores to the energy flow. The author regarded the caloric content of shell to zero because published combustion heats of 80 to 250 J/g were negligible compared with 13 to 21 kJ/g for flesh measured by him. 

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