Living Reference Work Entry

Marine Animal Forests

pp 1-25

Date: Latest Version

Activity Rhythm Measurement in Suspension Feeders

Abstract

Measurement of activities of benthic species is a recurrent problem. Variability in the size, aspects, type of movements, structures created to filter or collect the particles suspended in the water column, and falling on the sediment surface implicates the development of versatile measuring devices. Suspension feeding is a time-consuming process for the benthic species. The time spent filtering can be observed and recorded with sensors running in the background, capturing the ongoing activity. Depending on their position on or inside the substrate, species will adapt their way of capturing the particles and develop strategies and timings for the feeding events. Passive or active suspension feeding will be related to different energies expended to collect food. Recording the behavioral patterns is an important step in the knowledge of the animal energy budget. Some species are able to switch between passive and active mode, depending on the varying environmental conditions, such as the flow rate or the detection of increased particle densities. Simultaneous measure of individual activity and environmental variables, using associated sensors, can increase this knowledge.

Indices describing this activity can be produced by image analysis, coupled with specialized libraries developed sometimes on a species basis. Other techniques like valvometry may be used for measuring long-term, high-speed activities related to the shell opening in bivalves. Indirect variables including temperature, fluorometry, or other techniques can be used to study the pumping rate or the bioturbation effect of animal activities.

In this chapter some examples will be provided on the way of measuring the benthic suspension-feeding activities, among passive and active suspension feeders.

Keywords

Animal forest Benthic animals Activity measurement