On the trophic fate of Phaeocystis pouchetii (Hariot). II. Grazing rates of Calanus hyperboreus (Krøyer) on diatoms and different size categories of Phaeocystis pouchetii

Huntley, Mark E.; Tande, Kurt S.; Eilertsen, Hans Christian

doi:10.1016/0022-0981(87)90001-3

Cited by 95 publications

(44 citation statements)

References 31 publications

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“…Ingestion rates measured were comparable to or lower than rates found in grazing studies with other phytoplankton food; such inconsistencies may be attributed DISCUSSION to differences in Phaeocystis size-spectrum and quality, copepod species and methods applied. Phaeocystis Conclusions colonies were ingested at higher rates than single cells (Huntley et al 1987), the size of which is at the lower Although the evidence from our experiments is end of the size-range of particles efficiently retainable somewhat restricted by the few organisms tested. 3 by a variety of copepods (Nival & Nival 1976 Copepod predation on protozoa…”

Section: Copepod Grazing On Phaeocystismentioning

confidence: 55%

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Phaeocystis blooming enhanced by copepod predation on protozoa: evidence from incubation experiments

Hansen¹,

Reckermann²,

Breteler³

et al. 1993

Mar. Ecol. Prog. Ser.

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Laboratory experiments were carried out to investigate the effect of protozoan, copepod and comb~ned grazing on Phaeocystis biomass. Phaeocystis cf. globosa single cells were offered to 3 different protozoan species, to the calanoid copepod Temora longicornis, as well as to mixtures of both grazer types. The heterotrophic dinoflagellate Oxyrrhis marina and the oligotrich clhate Strombidinopsjs acuminatum ingested Phaeocystis at much higher rates than did the copepod Nevertheless, protozoan growth and ingestion rates were submaximal, indicating Phaeocyst~s to be subopt~mal food. The ohgotrich ciliate Strombidium elegans did not feed on Phaeocystis. In grazing experiments w~t h mixtures of both predator types, the decline of Phaeocystis single cells could be explained by protozoan grazing alone, implying no grazing by the copepods on Phaeocystis. Instead, copepods ingested the protozoans at high rates. Predation on 0. marina and S. acuminatum by T. longicornis resulted in a reduct~on of the total grazing pressure on Phaeocystis of 21 and 67 % respectively. We conclude that mesozooplankton predation on herbivorous ciliates and heterotrophic dinoflagellates, which consumed Phaeocystis cells, can considerably reduce the overall grazing pressure and may enhance Phaeocystis bloomng.

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Section: Copepod Grazing On Phaeocystismentioning

confidence: 55%

“…Huntley et al 1987, Hansen 1992. Ingestion rates measured were comparable to or lower than rates found in grazing studies with other phytoplankton food; such inconsistencies may be attributed DISCUSSION to differences in Phaeocystis size-spectrum and quality, copepod species and methods applied.…”

Section: Copepod Grazing On Phaeocystismentioning

confidence: 99%

Phaeocystis blooming enhanced by copepod predation on protozoa: evidence from incubation experiments

Hansen¹,

Reckermann²,

Breteler³

et al. 1993

Mar. Ecol. Prog. Ser.

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“…Bacterial consumption rates of acrylate in Weld samples increased when the > 20 m fraction containing P. globosa colonies was removed (Noordkamp et al 2000). And then there is the so-called legend of Phaeocystis unpalatability (Huntley et al 1987) that says that healthy colonies are not consumed due to some sort of chemical deterrence (Estep et al 1990). The observed negative eVects of Phaeocystis presence on other organisms may be a key to its bloom forming capacity; chemical deterrence could be a way to reduce grazing (Nejstgaard et al, this issue) as well as inhibiting competitors (allelopathy), thereby increasing Wtness.…”

Section: Introductionmentioning

confidence: 99%

Haemolytic activity of live Phaeocystis pouchetii during mesocosm blooms

et al. 2007

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Chemical defence is a potential mechanism contributing to the success of Phaeocystis species that repeatedly dominate the phytoplankton in coastal areas. Species within the genus Phaeocystis have long been suspected of imposing negative eVects on co-occurring organisms. Recently a number of toxins have been extracted and identiWed from Phaeocystis samples, but it is not clear if they do enhance the competitive advantage of Phaeocystis species.In the present study the cytotoxic impact of live Phaeocystis pouchetii to human blood cells in close proximity, regardless of the nature of the responsible mechanism, was quantiWed using a bioassay. Haemolytic activity was measured during blooms of P. pouchetii in mesocosms. These environments were chosen to mimic natural conditions including chemically mediated interactions that could trigger defensive and/or allelopathic responses of Phaeocystis.Haemolytic activity correlated with P. pouchetii numbers and was absent during the preceding diatom bloom. Samples containing live P. pouchetii cells showed the highest activity, while Wltered sea water and cell extracts were less haemolytic or without eVect. Dose-response curves were linear up to 70% lysis, and haemolysis in samples containing live P. pouchetii cells reached EC 50 values comparable to known toxic prymnesiophytes (1.9 * 10 7 cells l ¡1 ). Haemolytic activity was enhanced by increased temperature and light. The results indicate that unprotected and thus presumably vulnerable cells present in a P. pouchetii bloom may lyse within days.

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“…(e.g. Admiraal & van Kamp 1986, Huntley et al 1987, Tande & Bamstedt 1987, Weisse & Scheffel-Moser 1990), others avoid feeding on it, perhaps because of its low nutritional quality (Smith 1988, Verity & Smayda 1989, Claustre et al 1990). In some areas, large quantities of Phaeocystis sp.…”

Section: Introductionmentioning

confidence: 99%

Association of bacteria with Phaeocystis sp. In McMurdo Sound, Antarctica

Putt¹,

Miceli²,

Stoecker³

1994

Mar. Ecol. Prog. Ser.

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We present a microscopic study of bacteria and Phaeocystis sp. during the annual bloom in McMurdo Sound, Antarctica. During the initial phases of the bloom when Phaeocystls sp. was actively growing, bacterial abundance and cell size both ~ncreased, suggesting that the bacterial community was also actively growing. At 5 and 25 m, the median density of bacteria associated with Phaeocystissp. colonies ranged from about 2-to over 1 l-fold greater than over an equivalent area of a nearby region of the slide. On 7 out of 8 sampling dates, the length of bacteria associated with Phaeocystis sp. colonies was similar to or larger than pelagic bacteria from the same sample, suggesting that bacterial growth rates were not reduced by their proximity to the alga. In short, rather than bacteriocidal effects sometimes ascribed to Phaeocystjs sp., we observed a close association between both pelagic and epiphytic bacteria and Phaeocystis sp. throughout the bloom in McMurdo Sound. lnitial results with a strain of Phaeocystis pouchetii (CCMP 628) originally collected in Surinam and grown in culture suggest that differences between the results of this and previous studies might, at least in part, reflect strain differences. As the season progressed, disappearance of Phaeocystis sp. colonies in the upper water column corresponded to the appearance of a large bacterial bloom at and below 100 m depth. We speculate that in McMurdo Sound, the close alga-bacterial association might enhance remineralization of Phaeocystis sp. thus reducing the amount of organic material originatmy from the bloom which ultimately reaches the sediments.

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On the trophic fate of Phaeocystis pouchetii (Hariot). II. Grazing rates of Calanus hyperboreus (Krøyer) on diatoms and different size categories of Phaeocystis pouchetii

Cited by 95 publications

References 31 publications

Phaeocystis blooming enhanced by copepod predation on protozoa: evidence from incubation experiments

Phaeocystis blooming enhanced by copepod predation on protozoa: evidence from incubation experiments

Haemolytic activity of live Phaeocystis pouchetii during mesocosm blooms

Association of bacteria with Phaeocystis sp. In McMurdo Sound, Antarctica

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