Aquatic Sciences Meeting, Albuquerque 2001

SS20 Biological Control of Harmful Algal Blooms: Role of Grazers, Parasites, Viruses and Bacteria

Date: Monday, February 12, 2001, Time: 4:45:00 PM

Location: Cochiti/Taos

Bargu, S, , Inst. of Marine Sci., Univ. of California, Santa Cruz (USCS), Santa Cruz, CA, USA, sbargu@cats.ucsc.edu

Marinovic, B, , Inst. of Marine Sci., UCSC, Santa Cruz, CA, USA,

Mansergh, S, , Inst. of Marine Sci., UCSC, Santa Cruz, CA, USA,

Antrobus, R, , Inst. of Marine Sci., UCSC, Santa Cruz, CA, USA,

Silver, M, E, Inst. of Marine Sci., UCSC, Santa Cruz, CA, USA,

FEEDING RESPONSE OF KRILL TO THE TOXIN PRODUCING DIATOM PSEUDONITZSCHIA MULTISERIES

Krill is an important herbivore and critical prey item for many high level carnivores in Monterey Bay and elsewhere along the California coast. Here, some of these higher level consumers have recently been shown to be severely affected by toxins produced by the diatom Pseudonitzschia. To predict the possible role of krill in transferring the diatom toxin, we measured the grazing rates of local Euphausia pacifica and Thysanoessa spinifera collected between June 1999 and August 2000 on toxic Pseudonitzschia multiseries. We will present results showing that krill grazing rates are higher when P. multiseries has lower toxin concentrations per cell than when cell toxin levels are higher. Furthermore, the responses of the 2 krill species differed to a degree. Interestingly, krill collected during the mating seasons did not feed. These variable and complex responses are important to understand to predict toxin transfer from vectors such as krill to higher trophic levels during blooms of harmful algae.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks