Impact of zooplankton grazing on Alexandrium blooms in the offshore Gulf of Maine

Turner, Jefferson T.; Borkman, David G.

doi:10.1016/j.dsr2.2005.06.011

Cited by 44 publications

(36 citation statements)

References 18 publications

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“…We are aware that Alexandrium spp. most commonly occurs as part of a mixed assemblage of phytoplankton (Garcés et al, 2005;Turner and Borkman, 2005), and other grazers can select against -but not entirely avoid -Alexandrium (Teegardern and Cembella, 1996;Teegarden, 1999). Hence, we cannot generalize the results observed here to other grazers.…”

Section: Discussioncontrasting

confidence: 51%

“…Factors such as low copepod abundances and grazing rates in conjunction with low Alexandrium spp. abundances relative to other algal species often results in an insignificant grazing impact by copepods (Turner and Anderson, 1983;Calbet et al, 2003;Turner and Borkman, 2005). However, in the Gulf of Maine the high grazing rates of nearshore copepods on toxic Alexandrium fundyense have been found to be sufficient to impact the population growth rate of the toxic dinoflagellate (Campbell et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

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Comparison of the functional and numerical responses of resistant versus non-resistant populations of the copepod Acartia hudsonica fed the toxic dinoflagellate Alexandrium tamarense

Colin

Dam

2007

Harmful Algae

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The functional and numerical responses of grazers are key pieces of information in predicting and modeling predator-prey interactions. It has been demonstrated that exposure to toxic algae can lead to evolved resistance in grazer populations. However, the influence of resistance on the functional and numerical response of grazers has not been studied to date. Here, we compared the functional and numerical responses of populations of the copepod Acartia hudsonica that vary in their degree of resistance to the toxic dinoflagellate Alexandrium tamarense. In common environment experiments carried out after populations had been grown under identical conditions for several generations, female copepods were offered solutions containing different concentrations of either toxic A. tamarense or the non-toxic green flagellate Tetraselmis sp. ranging from $25 to 500 mgC L À1, and ingestion and egg production rates were measured. Throughout most of the range of concentrations of the toxic diet, copepod populations that had been historically exposed to toxic blooms of Alexandrium exhibited significantly higher ingestion and egg production rates than populations that had little or no exposure to these blooms. In contrast, there were no significant differences between populations in ingestion or egg production for the non-toxic diet. Hence, the between population differences in functional and numerical response to A. tamarense were indeed related to resistance. We suggest that the effect of grazer toxin resistance should be incorporated in models of predator and toxic prey interactions. The potential effects of grazer toxin resistance in the development and control of Alexandrium blooms are illustrated here with a simple simulation exercise. #

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Section: Discussioncontrasting

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Comparison of the functional and numerical responses of resistant versus non-resistant populations of the copepod Acartia hudsonica fed the toxic dinoflagellate Alexandrium tamarense

Colin

Dam

2007

Harmful Algae

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“…Given the responses measured here in a range of Alexandrium cell concentrations and toxicities, as well as field-measured feeding of C. finmarchicus in waters containing Alexandrium spp. (Teegarden et al, 2001;Campbell et al, 2004;Turner and Borkman, 2005) in which selective feeding was not observed, we conclude that in natural settings C. finmarchicus will feed on Alexandrium at any concentration or toxin level; toxicity imparts little or no advantage to Alexandrium in deterring this grazer. One caveat to this conclusion is that C. finmarchicus was not challenged in this study with Alexandrium cells in mixtures dominated by abundant non-toxic diatoms, as might be the case during initiation of an Alexandrium bloom.…”

Section: Discussionmentioning

confidence: 48%

Copepod feeding response to varying Alexandrium spp. cellular toxicity and cell concentration among natural plankton samples

et al. 2008

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“…The putative function of dinoflagellate toxins is often assumed to be chemical defense but although acute responses such as death, incapacitation, altered swimming behavior, and reduced fecundity and egg-hatching success have been reported after ingestion of highly toxic algae by microzooplankton and macrozooplankton in laboratory experiments (reviewed by Turner et al 1998), these effects may rarely occur in nature because of low individual grazing rates on dinoflagellate cells and grazing on other food sources such as microflagellates and diatoms (Turner and Borkman 2005).…”

Section: Phytoplankton-zooplankton Chemical Interactionsmentioning

confidence: 99%

New trends in marine chemical ecology

Ianora

Boersma

Casotti

et al. 2006

Estuaries and Coasts: J ERF

123

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This essay is the outcome of a colloquium convened in November 2005 at the Benthos Laboratory of the Stazione Zoologica Anton Dohrn in Ischia, Italy, on chemical ecology and the role of secondary metabolites in the structuring and functioning of marine biodiversity. The participants of the workshop are part of the European Network of Excellence MarBEF (Marine Biodiversity and Ecosystem Function), a consortium of 56 European marine institutes to integrate and disseminate knowledge and expertise on marine biodiversity. Here we review some of the new trends and emerging topics in marine chemical ecology. The first section deals with microbial chemical interactions. Microbes communicate with each other using diffusible molecules such as N-acylhomoserine lactones (AHL). These are regulators in cell-density-dependent gene regulation (quorum sensing) controlling microbial processes. In chemical interactions with higher organisms, microbes can act either as harmful pathogens that are repelled by the host's chemical defense or as beneficial symbionts. These symbionts are sometimes the true producers of the host's secondary metabolites that have defensive and protective functions for their hosts. We also describe how allelochemicals can shape phytoplankton communities by regulating competition for available resources, and also interactions among individuals of the same species. Compounds such as the diatom-derived unsaturated aldehydes have been demonstrated to act as infochemicals, and they possibly function as a diffusible bloom-termination signal that triggers an active cell death and bloom termination at sea. The same molecules have also been shown to interfere with the reproductive capacity of grazing animals deterring future generations of potential predators. Such compounds differ from those that act as feeding deterrents since they do not target the predator but its offspring. Many of the neurotoxins produced by dinoflagellates act as feeding deterrents, and laboratory experiments have shown that ingestion of these algae by some microzooplankton and macrozooplankton can cause acute responses such as death, incapacitation, altered swimming behavior, and reduced fecundity and egg-hatching success. These effects may rarely occur in nature because of low individual grazing rates on dinoflagellate cells and grazing on other food sources such as microflagellates and diatoms. We also consider the nutritional component of marine plant-herbivore interactions, especially in the plankton, and the information available on the effects of growing conditions of algae on the production of toxic metabolites. Species producing saxitoxins seem to consistently produce the highest amounts of toxins (on a per cell basis) in the exponential phase of growth, and there is a decrease in their production under nitrogen, but not under phosphorus stress, where the production actually increases. We try to explain the circumstances under which organisms defend themselves chemically and argue that the most likely explanatory model for ...

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Impact of zooplankton grazing on Alexandrium blooms in the offshore Gulf of Maine

Cited by 44 publications

References 18 publications

Comparison of the functional and numerical responses of resistant versus non-resistant populations of the copepod Acartia hudsonica fed the toxic dinoflagellate Alexandrium tamarense

Comparison of the functional and numerical responses of resistant versus non-resistant populations of the copepod Acartia hudsonica fed the toxic dinoflagellate Alexandrium tamarense

Copepod feeding response to varying Alexandrium spp. cellular toxicity and cell concentration among natural plankton samples

New trends in marine chemical ecology

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