Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 11:30:00 AM

Location: Mesilla

Krug, P, J, UCLA, Los Angeles, USA, pkrug@biology.ucla.edu

Zimmer, R, K, UCLA, Los Angeles, USA, z@protos.lifesci.ucla.edu

LARVAL SETTLEMENT: CHEMICAL MARKERS FOR TRACING PRODUCTION, TRANSPORT AND DISTRIBUTION OF WATERBORNE CUES IN THE FIELD

To understand the mechanisms governing larval settlement, measurements of behavior have been combined with hydrodynamics and the distribution of waterborne cues in field habitats. Using the estuarine herbivore Alderia modesta, we investigated the (1) behavior of short-lived vs. long-lived larvae, (2) role of soluble vs. surface-associated cues, and (3) transport of natural markers for the waterborne cue. Larvae of Alderia metamorphosed in response to both dissolved and surface-bound carbohydrates exclusively derived from the adult host alga, Vaucheria longicaulis. Both lecithotrophic and competent planktotrophic larvae immediately responded to the waterborne cue by increasing their turning rate and changing swimming speed. During low tides, the dissolved cue accumulated in pore water within algal mats, and was released into overlying sea water on the next flood tide. The flux of natural markers (mannitol and glucose) out of Vaucheria patches was measured; marker concentration was positively correlated with bioactivity of water above Vaucheria during initial immersion and the subsequent hours of a high tide. Thus, how dissolved cues mediate settlement can be determined by tracing production and distribution of waterborne compounds in the field.

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Aquatic Sciences Meeting, Albuquerque 2001

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