Low grazing impact of mesozooplankton on the microbial communities of the Alboran Sea: a possible case of inhibitory effects by the toxic dinoflagellate Gymnodinium catenatum

Calbet, Albert; Broglio, Elisabetta; Saiz, Enric; Alcaraz, Miquel

doi:10.3354/ame026235

Cited by 31 publications

(13 citation statements)

References 53 publications

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“…However, other previous studies, conducted in very different environments and different zooplankton communities, yielded conclusions similar to ours, with daily grazing impacts on ciliate standing stocks in the order of 5% (Atkinson 1996, Atkinson et al 1996, Lonsdale et al 2000, Batten et al 2001, Calbet et al 2002b, Zeldis et al 2002. In those studies, and in ours as well, feeding rates on ciliates were high, the low grazing impact appearing to be the mere result of the low ciliate abundance in the field.…”

Section: Zooplankton Grazing Impactsupporting

confidence: 88%

“…Grazing impact is calculated as the percentage of ciliate standing stock ingested by the crustacean community in a day, when only considering the species studied or when considering the whole crustacean community, assuming an average clearance rate for the non-studied species (see 'Materials and methods' section) Dolan (1991) and Fessenden & Cowles (1994) reported episodes of daily predation pressures up to 45 and 200% of ciliate standing stock. However, other previous studies, conducted in very different environments and different zooplankton communities, yielded conclusions similar to ours, with daily grazing impacts on ciliate standing stocks in the order of 5% (Atkinson 1996, Atkinson et al 1996, Lonsdale et al 2000, Batten et al 2001, Calbet et al 2002b, Zeldis et al 2002. In those studies, and in ours as well, feeding rates on ciliates were high, the low grazing impact appearing to be the mere result of the low ciliate abundance in the field.…”

Section: Zooplankton Grazing Impactsupporting

confidence: 88%

“…the existence of certain prey that are ingested in a higher or lower proportion than expected from their field relative abundance) was evaluated in different ways. Although an acute difference in the clearance rates of a predator on different prey within an experiment may be indicative of selective feeding patterns, another visual way to approach selection, however, is the one by plotting the prey contribution to the zooplankton diet against its availability (Calbet et al 2002b). In this kind of plot, values that fall above the line 1:1 are indicative of prey preference, whereas values falling below the line represent deterrence for the specific prey.…”

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confidence: 99%

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Trophic impact and prey selection by crustacean zooplankton on the microbial communities of an oligotrophic coastal area (NW Mediterranean Sea)

Broglio¹,

Saiz²,

Calbet³

et al. 2004

Aquat. Microb. Ecol.

Self Cite

105

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Selection for ciliates in the presence of phytoplankton has been previously shown for some species of copepods. However, the factors determining preference for this heterotrophic prey and how crustacean zooplankton predation can affect the ciliate community are not yet fully understood. In this study, we investigated predation rates on phytoplankton and ciliates by the most abundant copepod and cladoceran species in a coastal area of the oligotrophic NW Mediterranean Sea monthly over an annual cycle. Three major results were apparent. Firstly, ciliates were important contributors to zooplankton diet, representing a median of 37 and 17% of the carbon intake, and 51 and 34% of the nitrogen intake for copepods and cladocerans, respectively. Secondly, ciliates were positively selected in most cases, this selection was species specific and apparently independent of phytoplankton concentration. And finally, in spite of the high clearance rates on ciliates, the impact of the crustacean community on the ciliate standing stock was low (median 2%), suggesting a bottom-up control of the ciliate community. KEY WORDS: Copepods · Cladocerans · Ciliates · Food web · NW MediterraneanResale or republication not permitted without written consent of the publisher Aquat Microb Ecol 35: 65-78, 2004 al. 2002a) is commonly used to argue that ciliates may be important to zooplankton diet. Yet, relatively few studies have paid attention to the actual nutritional contribution of ciliates as carbon and nitrogen sources for zooplankton metabolism, and compared them to the one supplied by phytoplankton ingestion (e.g. Froneman et al. 1996, Batten et al. 2001. Furthermore, it is scarcely known how ciliate contribution to crustacean zooplankton diet may vary by season, in which different zooplankton species and microbial communities occur.A second aspect of interest in the trophic interactions between ciliates and zooplankton deals with feeding selection mechanisms. Copepods frequently exhibit higher clearance rates on ciliates than on phytoplankton (e.g. Gifford & Dagg 1991, Fessenden & Cowles 1994, Levinsen et al. 2000, a fact that has been attributed to positive selection patterns. What exactly determines this positive selection is not clear, and factors like food quality and encounter rates have been proposed (Jonsson & Tiselius 1990, Stoecker & Capuzzo 1990. However, the preference for a given food item could also be dependent on the availability of an alternative suitable prey, and switching responses may appear as well (Kiørboe et al. 1996, Gismervik & Andersen 1997. Unfortunately, few field studies have considered these aspects.Finally, little is known concerning the strength of the trophic control that zooplankton may exert on ciliate communities. Because of their nexus position, as both prey for zooplankton and top predators for other microbes, ciliates represent a crucial link within marine planktonic food webs. Empirical evidence up to now, however, indicates that copepods, the major component of mesozooplankton, in g...

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Section: Zooplankton Grazing Impactsupporting

confidence: 88%

Section: Zooplankton Grazing Impactsupporting

confidence: 88%

mentioning

confidence: 99%

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Trophic impact and prey selection by crustacean zooplankton on the microbial communities of an oligotrophic coastal area (NW Mediterranean Sea)

Broglio¹,

Saiz²,

Calbet³

et al. 2004

Aquat. Microb. Ecol.

Self Cite

105

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“…Dam et al, 1995;Saiz et al, 1999;Calbet et al, 2002). Even though the importance of protozooplankton in pelagic food webs has been well established, studies targeting this group in the Irish Sea are still rare (i.e.…”

Section: Introductionmentioning

confidence: 98%

The importance of protozooplankton as prey for copepods in the coastal areas of the central Irish Sea

2009

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This study evaluates food supply for copepods, highlighting the trophic relationship between copepods and protozooplankton. To test the hypotheses that protozooplankton prey are capable of sustaining the copepod standing stock in the western Irish Sea, the taxonomic and size composition of these two groups and the size-specific predation of copepods on protozooplankton were investigated. Protozooplankton and copepod samples were collected off the southwest coast of the Isle of Man using 1.7 l Niskin water bottles and two nets (64 and 280 lm meshes), respectively. Copepod predation on protozooplankton was calculated using weight-specific clearance rates from the literature, considering the availability of prey that was accessible to a given size of copepod. Low protozooplankton biomass was dominated by small cells (\60 lm), and high copepod biomass was dominated by small species, which were more efficiently collected by a 64-lm mesh net. However, large copepods were only collected by a 280-lm mesh net, suggesting that the combination of the two nets provided a better estimate of copepod biomass. Predation by the copepod assemblage in the Irish Sea removed 1-47% and 0.5-22% of ciliates and dinoflagellates standing stock, respectively, resulting in 1-40% of the copepod feeding requirement per day. Contrary to our hypothesis, copepods could not meet their feeding requirements by grazing only on the microzooplankton prey (15-200 lm), and other food sources (i.e. nanoplankton) must be important additional dietary components to copepods in the Irish Sea.

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“…For example, some dinoflagellates (Gymnodinium catenatum, Dinophysis acuminata, Alexandrium spp.) synthesize metabolites that inhibit feeding and growth of copepods (Carlsson et al 1995, Teegarden 1999, Calbet et al 2002. Some algae synthesize multiple compounds which inhibit growth of bacteria, other phytoplankton, protozoan and metazoan grazers (Fistarol et al 2003) to structure planktonic communities from both the top down and bottom up.…”

Section: Eight Principles Of Phytoplankton Community Assemblymentioning

confidence: 99%

Phytoplankton community ecology: principles applied in San Francisco Bay

Cloern¹,

Dufford²

2005

Mar. Ecol. Prog. Ser.

269

175

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In his seminal 1961 paper 'The paradox of the plankton' Am Nat 95:137-147, G. E. Hutchinson asked why many species of phytoplankton can coexist while competing for a small number of limiting resources in an unstructured habitat. Hutchinson anticipated the resolution of his paradox, recognizing that communities are organized by processes beyond resource competition including species interactions, habitat variability and dispersal. Since 1961 we have made fundamental discoveries that have revolutionized our conceptual understanding of pelagic ecology, including (1) habitat heterogeneity at all scales relevant to plankton population dynamics, (2) community shifts in response to global climate cycles, (3) fast and selective predation as a powerful top-down force to shape phytoplankton communities, (4) turbulent mixing as a physical process that selects species on the basis of their size and form, (5) mixotrophy that allows some algal species to tap organic nutrient pools and function at multiple trophic levels, (6) taxon-specific life cycles including alternating vegetative and resting stages, and (7) the pelagic as an open system where communities are continually reshaped by species immigration. Here we synthesize these discoveries to show how they validate and amplify Hutchinson's hypothesis that phytoplankton communities are assembled by many processes. Our synthesis is built around observations of phytoplankton species composition from a decade of study in San Francisco Bay, used as a case study to illustrate the contemporary principles of phytoplankton community ecology. We apply these principles to address 2 central questions:

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Low grazing impact of mesozooplankton on the microbial communities of the Alboran Sea: a possible case of inhibitory effects by the toxic dinoflagellate Gymnodinium catenatum

Cited by 31 publications

References 53 publications

Trophic impact and prey selection by crustacean zooplankton on the microbial communities of an oligotrophic coastal area (NW Mediterranean Sea)

Trophic impact and prey selection by crustacean zooplankton on the microbial communities of an oligotrophic coastal area (NW Mediterranean Sea)

The importance of protozooplankton as prey for copepods in the coastal areas of the central Irish Sea

Phytoplankton community ecology: principles applied in San Francisco Bay

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