Copepod predation on phagotrophic ciliates in Oregon coastal waters

Fessenden, Lynne; Cowles, TJ

doi:10.3354/meps107103

Cited by 166 publications

(103 citation statements)

References 27 publications

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“…10). Some studies suggest that the effects of micrometazoans grazing on phytoplankton may be mediated mostly by their control of microzooplankton populations (Fessenden and Cowles 1994). However, our results indicate that their grazing pressure on protozoans appeared to be modest in agreement with other previous studies for mesozooplankton (Broglio et al 2004).…”

Section: Copepod Naupliicontrasting

confidence: 48%

Trophic role and carbon budget of metazoan microplankton in northwest Mediterranean coastal waters

Almeda

Calbet

Alcaraz

et al. 2011

Limnology & Oceanography

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We determined the feeding rates, trophic effect, and growth efficiencies of natural assemblages of metazoan microplankton from a coastal site in the northwest (NW) Mediterranean over a seasonal cycle in laboratory incubations. Micrometazoans, i.e., multicellular heterotrophic plankters between 20 and 200 mm, were mainly constituted by invertebrate larval stages. Copepod nauplii and copepodites dominated the community, except in April, when polychaete larvae dominated. We analyzed the grazing pressure of micrometazoans on chlorophyll a (Chl a; total and . 10 mm), nanoflagellates, phototrophic nanoflagellates, dinoflagellates, diatoms, and ciliates. Micrometazoans grazed on all the prey groups, with carbon-specific ingestion rates ranging from 0.31 to 1.24 d 21 . The gross growth efficiencies for the entire metazoan microplankton community, calculated as the slope of the linear regression relating specific growth rates vs. specific ingestion rates, varied between 0.27 and 0.39. The respiratory carbon losses of micrometazoans depended on temperature and ranged from 0.16 to 0.36 d 21 , with a Q 10 5 2. The average net growth efficiency, 0.41, was independent of temperature and food availability. Overall micrometazoans have higher specific growth rates than, but similar food conversion efficiencies to, mesozooplankton. The grazing effect on the standing stock of the different prey was , 1% d 21 for Chl a (total and . 10 mm) and , 2.5% d 21 for the other studied prey, which seems insufficient to exert relevant control on phytoplankton and protozoan dynamics. The inclusion of micrometazoans did not change appreciably our current view of the role of metazooplankton in marine trophic webs of NW Mediterranean coastal waters.

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Section: Copepod Naupliicontrasting

confidence: 48%

Trophic role and carbon budget of metazoan microplankton in northwest Mediterranean coastal waters

Almeda

Calbet

Alcaraz

et al. 2011

Limnology & Oceanography

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“…Although microzooplankton might contribute less than phytoplankton to mesozooplankton diets in terms of ingestion rates in rich food conditions (Calbet and Saiz, 2005;Liu et al, 2005b), our result suggested that carnivorous feeding was always a reason for the reduction of the clearance rate of phytoplankton by mesozooplankton assemblage even during phytoplankton bloom in addition to functional response. Preference on microzooplankton by copepods during phytoplankton bloom and associated trophic cascades were also reported in other coastal and estuarine waters (e.g., Fessenden and Cowles, 1994;Liu et al, 2005a).…”

Section: The Effect Of Mesozooplankton Carnivorymentioning

confidence: 97%

“…It has been reported by many field studies that when omnivorous species dominate in assemblage, mesozooplankton or copepods (a major group of mesozooplankton) often prefer feeding on microzooplankton to phytoplankton due to larger sizes and higher nutritional quality of microzooplankton (e.g., Stoecker and Capuzzo, 1990;Gifford, 1991;Fessenden and Cowles, 1994;Atkinson et al, 1996;Nejstgaard et al, 2001;Zeldis et al, 2002;Calbet and Saiz, 2005;Liu et al, 2005b;Gifford et al, 2007). Predation on microzooplankton is also an important feeding strategy of omnivorous species that are able to switch their feeding behaviors to conquer food limitation or to survive during nuisance phytoplankton blooms in coastal waters (Kiørboe et al, 1996;Nejstgaard et al, 1997;Gifford et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Seasonal Variability of Mesozooplankton Feeding Rates on Phytoplankton in Subtropical Coastal and Estuarine Waters

2017

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In order to understand how mesozooplankton assemblages influenced phytoplankton in coastal and estuarine waters, we carried out a monthly investigation on mesozooplankton composition at two contrasting stations of Hong Kong coastal and estuarine waters and simultaneously conducted bottle incubation feeding experiments. The assemblage of mesozooplankton was omnivorous at both stations with varying carnivory degree (the degree of feeding preference of protozoa and animal food to phytoplankton) and the variations of carnivory degree were significantly associated with microzooplankton biomass (ciliates for the coastal station, both ciliates and dinoflagellates for the estuarine stations) and physical environmental parameters (primarily salinity). High carnivory was primarily due to high composition of noctilucales, Corycaeus spp., Oithona spp. and Acartia spp. Results of feeding experiments showed that grazing impacts on phytoplankton ranged from −5.9 to 17.7%, while the mean impacts were just <4% at both stations. The impacts were size-dependent, by which mesozooplankton consumed around 9% of large-sized phytoplankton while indirectly caused an increase of 4% of small-sized phytoplankton. Mesozooplankton clearance rate on phytoplankton, calculated from the log response of chlorophyll a concentrations by the introduction of bulk grazers after 1-day incubation, was significantly reduced by increasing carnivory degree of the mesozooplankton assemblage. The mechanism for the reduction of mesozooplankton clearance rate with increasing carnivory degree was primarily due to less efficient of filtering feeding and stronger trophic cascades due to suppression of microzooplankton. The feeding rates of mesozooplankton on microzooplankton were not obtained in this study, but the trophic cascades indirectly induced by mesozooplankton carnivorous feeding can be observed by the negative clearance rate on small-sized phytoplankton. Overall, the main significance of this study is the empirical relationship between carnivory degree and clearance rate, which allow researchers to potentially predict the herbivory of mesozooplankton in the nature without conducting feeding experiments.

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“…Because nonpigmented ciliates and heterotrophic dinoflagellates are generally available, and even preferred, as prey by copepods (Stoecker and Capuzzo 1990;Kleppel 1993;Fessenden and Cowles 1994;Suzuki et al 1999;Levinsen et al 2000;Nejstgaard et al 2001), the ability to directly investigate feeding on nonpigmented organisms by copepods is of considerable importance. Yet, current methodological limitations hamper our ability to quantify Estimated time for 50% gut evacuation was 14.4 min at 5°C; P(x) = P 0 × exp (-k × x) , P 0 = 11.4; SE = 1.1; P < 10 -4 ; k = 0.048; SE = 0.008; P < 10 -4 ; r 2 = 0.86; df = 18.…”

Section: Discussionmentioning

confidence: 99%

Molecular detection of algal prey in copepod guts and fecal pellets

Nejstgaard

Frischer

Raule

et al. 2003

Limnology & Ocean Methods

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The ability to obtain information about feeding selectivity and rates in situ for key organisms such as copepods and other zooplankton is vital for understanding the mechanisms structuring marine ecosystems. Copepods feed on a wide range of prey, and there are presently no methods available to directly quantify zooplankton feeding on all different prey types in situ. Therefore, the development of a new nonintrusive direct method is necessary to gain a better understanding of the trophic interactions in aquatic ecosystems. Molecular methods based on the polymerase chain reaction have recently become an important tool to study predation by arthropods, particularly insects. Here we present the first results of successful molecular detection of a specific prey consumed by calanoid copepods from gut and fecal material. Using the calanoid copepod species Calanus finmarchicus consuming the haptophyte alga Emiliania huxleyi as a model system, 18S ribosomal DNA originating from E. huxleyi was unambiguously detected in whole DNA extracts from copepods and from their fecal pellets. The results also suggest that prey DNA may be quantified for determination of prey-specific zooplankton feeding rates. However, significantly more research under controlled laboratory and field conditions will be required to achieve these objectives. We hypothesize that molecular methods will become an important tool with the potential to quantify undisturbed trophic interactions between individual predators and all their prey in the complex natural plankton.

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Copepod predation on phagotrophic ciliates in Oregon coastal waters

Cited by 166 publications

References 27 publications

Trophic role and carbon budget of metazoan microplankton in northwest Mediterranean coastal waters

Trophic role and carbon budget of metazoan microplankton in northwest Mediterranean coastal waters

Seasonal Variability of Mesozooplankton Feeding Rates on Phytoplankton in Subtropical Coastal and Estuarine Waters

Molecular detection of algal prey in copepod guts and fecal pellets

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