Copepod feeding behaviour and egg production during a dinoflagellate bloom in the North Sea (original) (raw)
Related papers
Marine Ecology-progress Series, 2001
Experiments were conducted over 10 to 20 d periods to study the grazing and reproductive success of the copepod Temora stylifera fed on unialgal cultures of the diatom Thalassiosira rotula (THA) or the dinoflagellate Prorocentrum minimum (PRO), as well as mixtures of THA and PRO (MIX experiments) and alternating diets of THA and PRO switched daily (SWITCH experiments). Adult females ate both THA and PRO, and while rates of feeding on the 2 diets were similar in terms of carbon ingestion, egg production was generally higher on the diatom diet. In contrast, copepod egg-hatching success was low on the diatom diet, declining rapidly after 2 d from > 80 to 0% by Day 17. The diminution in hatching success was slower when females were fed MIX or SWITCH diets, but nonetheless diminished to 0 and < 25% by the end of the experiment, depending on the incubation method. Only in the case of the PRO diet was egg viability high and stable with time (87 to 96%), regardless of whether female and male couples were incubated as individual couples in crystallizing dishes or as triplicate couples in rotating bottles. However, in most other cases, the incubation method (crystallizing dishes vs rotating bottles) had very strong effects on egg and fecal pellet production, and hatching success. Higher egg production rates were generally obtained when females were incubated in crystallizing dishes, whatever the diet, although fecal pellet production rates were significantly higher in the rotating bottle experiments in most cases. Egg-hatching success was also strongly affected by incubation method, with generally higher hatching rates in the rotating bottles. This was probably due to the fragility of non-viable eggs, which were more easily destroyed by mechanical disturbance in rotating bottle experiments. The results support the recent discovery that reproductive failure in copepods can be due to deleterious antimitotic compounds present in some diatoms that arrest normal embryonic division. Reduction in egg viability was not only visible when females were fed unialgal diatom diets, but also when they were fed mixed diets. However, on mixed diets there was a 'dilution effect' in that hatching was reduced by approximately half, and this took about twice as long to occur. The evolutionary advantages for diatoms in producing antimitotic compounds are discussed, as well as questions of why copepods feed on diatoms with impunity, even though some diatoms are detrimental to copepod reproductive success.
First evidence of some dinoflagellates reducing male copepod fertilization capacity
Limnology and …, 1999
Evidence is presented that hatching failure in Temora stylifera eggs can depend on poor sperm quality. Three dinoflagellate diets, Prorocentrum micans, Gymnodinium sanguinium, and Gonyaulax polyedra, significantly modified spermatophore production and reduced the fertilization capacity of male sperm after 6-12 d of continuous feeding. Two other diets, the dinoflagellate P. minimum and the prymnesiophycean Isochrysis galbana, had no effect on hatching success, which remained high (Ͼ89%) and stable with time. A reduction in fertilization capacity was neither due to maternal effects nor to male age since hatching success returned to normal upon the introduction of freshly caught wild males or males conditioned with a good diet such as P. minimum for the same length of time as couples fed with the poor diets, P. micans, G. sanguinium, and G. polyedra. Confocal microscope images of unhatched eggs colored with a nucleus-specific fluorescent dye confirmed that these eggs had not been fertilized. Experiments with Calanus helgolandicus females, which did not require reinsemination and which were fed the same diets that induced hatching failure in T. stylifera, showed no change in hatching success with time.
ICES Journal of Marine Science, 2012
Vehmaa, A., Kremp, A., Tamminen, T., Hogfors, H., Spilling, K., and Engström-Öst, J. 2012. Copepod reproductive success in spring-bloom communities with modified diatom and dinoflagellate dominance. – ICES Journal of Marine Science, 69: 351–357. Dinoflagellates have increased and diatoms decreased in the Baltic Sea in recent decades, possibly because of changes in the climate and altered patterns of stratification. The hypothesis that grazing copepods would benefit from the change in species composition was tested experimentally by studying the reproductive output of the crustacean copepod Eurytemora affinis in five Baltic Sea phytoplankton spring communities dominated by different dinoflagellates (Biecheleria baltica, Gymnodinium corollarium) and diatoms (Chaetoceros cf. wighamii, Skeletonema marinoi, and Thalassiosira baltica). After a 5-d acclimation and a 4-d incubation, egg production, egg hatching success, and the RNA:DNA ratio of E. affinis were measured. Egg production was h...
Journal of Experimental Marine Biology and Ecology, 2011
Mild winters are modifying the plankton spring bloom composition so that diatoms are decreasing and dinoflagellates increasing. We used two common spring bloom phytoplankton species, a diatom and a dinoflagellate to study the effects of changing bloom composition on the reproduction of the calanoid copepod Acartia bifilosa Giesbrecht, a dominant species in the northern Baltic Sea. Egg production was significantly higher when copepods were fed with Scrippsiella hangoei (Schiller) Larsen dinoflagellates or a mixture of Scrippsiella and Skeletonema marinoi Sarno and Zingone diatoms than when they were provided with Skeletonema only. This effect was observed despite the fact that the Skeletonema strain did not produce polyunsaturated aldehydes (PUAs) and its nutritional quality was high according to polyunsaturated fatty acid (PUFAs) and sterol measurements, and moderate according to mineral (C:N and C:P) measurements. When offered mixtures of Skeletonema and Scrippsiella, copepods ingested both, even when the other one was rare. This indicates potential positive effect of multispecies diets not verified in this study. Here we show that increasing dinoflagellate:diatom ratio might have a positive effect on copepod reproduction.
Marine Biological Journal, 2020
The ubiquitous copepod species Arctodiaptomus salinus (Daday, 1885) and Calanipeda aquaedulcis (Krichagin, 1873) are important components of food chains of numerous fresh- and saltwater areas. These copepods are suitable for feeding larvae of both marine and freshwater fish species; however, influence of nutrition on the production characteristics of these species is not well understood. Previously we determined that monocultures of microalgae Dinophyceae and Prymnesiophyceae are optimal feeding objects for egg production by females of A. salinus and C. aquaedulcis, survival rate, and development time of these copepods throughout ontogenesis. The aim of this work was to determine the production characteristics of copepods A. salinus and C. aquaedulcis under optimal temperature conditions depending on the model of the feeding with a mixture of microalgae Dinophyceae and Prymnesiophyceae. The highest survival rates of A. salinus from the naupliar stage to the adult one (93–95 %) were ...
Journal of Plankton Research, 2007
Among studies of copepod grazers fed harmful algae, decreased grazing and fecundity are the most common results. The causes of decreased grazing (physiological incapacitation, behavioral avoidance or lack of stimulation) and decreased fecundity (toxic versus nutritional effect) vary among studies. This study used a series of controlled laboratory experiments to investigate the cause of decreased grazing and fecundity in the copepod Acartia tonsa fed sole and mixed diets of the harmful alga, Karenia brevis. Copepods fed K. brevis mixed with the nutritionally viable dinoflagellate Peridinium foliaceum had higher ingestion rates and offspring production than copepods fed a sole diet of K. brevis (even when K. brevis was virtually nontoxic). Copepods fed mixtures did not discriminate between P. foliaceum and K. brevis while feeding. The results of this study suggest that K. brevis is not toxic to A. tonsa but lacks some chemical component responsible for stimulating a grazing response in A. tonsa as well as the nutritional requirements for normal offspring production.
Marine Ecology Progress Series, 2006
Egg production rates (EPR) by Calanus helgolandicus females were investigated with specimens sampled weekly, from April to November 2003 and from March to October 2004, at a station located in the English Channel off Roscoff. Comparison of results between 1994, 2003 and 2004 showed that C. helgolandicus was a late spawner in 1994 and became an early spawner in 2003 and 2004. In all cases high variations in EPR were observed, which could not be correlated to phytoplankton biomass, expressed as diatom, chlorophyll a, particulate carbon and nitrogen concentrations in 2003 and 2004. Neither were they correlated to food quality, expressed as C/N ratio. To explain this mismatch between EPR and food concentration, a series of mixed phytoplankton species dominated by diatoms (≥11 µm filtrate representing natural diatom assemblages: NDA) and 7 single diatom species, all occurring during blooms in the field, were assayed as diets with C. helgolandicus females. Ingestion of diatoms by females was estimated by faecal pellet production rates and complementary scanning electron microscopy examinations of diatom remains in pellets. Depending on diatom species in diets, EPR was either increased or depressed 2 to 3 d after food uptake by females had started. The EPR decrease was reversible, when diatom diets were replaced by the dinoflagellate Prorocentrum minimum. This effect was also observed when females were transferred to natural phytoplankton populations from the English coast of the Channel close to Plymouth, where food composition in the field differed compared to that off Roscoff. EPR ceased completely when the concentration of NDA diets was artificially increased, but recovered after a shift to a dinoflagellate diet. These results indicate that phytoplankton dominated by diatoms can impair C. helgolandicus egg production in the field. This effect was not related to the production of polyunsaturated aldehydes by diatoms. Limitations due to unidentified essential compounds not provided by the metabolism of diatoms, or unknown diatom-derived toxins, were probably involved.
Marine Biology, 2007
Egg production rates (EPR) by Calanus helgolandicus females were investigated with specimens sampled weekly, , at a station located in the English Channel off Roscoff. Comparison of results between 1994Comparison of results between , 2003Comparison of results between and 2004 showed that C. helgolandicus was a late spawner in 1994 and became an early spawner in 2003 and 2004. In all cases high variations in EPR were observed, which could not be correlated to phytoplankton biomass, expressed as diatom, chlorophyll a, particulate carbon and nitrogen concentrations in 2003 and 2004. Neither were they correlated to food quality, expressed as C/N ratio. To explain this mismatch between EPR and food concentration, a series of mixed phytoplankton species dominated by diatoms (≥11 µm filtrate representing natural diatom assemblages: NDA) and 7 single diatom species, all occurring during blooms in the field, were assayed as diets with C. helgolandicus females. Ingestion of diatoms by females was estimated by faecal pellet production rates and complementary scanning electron microscopy examinations of diatom remains in pellets. Depending on diatom species in diets, EPR was either increased or depressed 2 to 3 d after food uptake by females had started. The EPR decrease was reversible, when diatom diets were replaced by the dinoflagellate Prorocentrum minimum. This effect was also observed when females were transferred to natural phytoplankton populations from the English coast of the Channel close to Plymouth, where food composition in the field differed compared to that off Roscoff. EPR ceased completely when the concentration of NDA diets was artificially increased, but recovered after a shift to a dinoflagellate diet. These results indicate that phytoplankton dominated by diatoms can impair C. helgolandicus egg production in the field. This effect was not related to the production of polyunsaturated aldehydes by diatoms. Limitations due to unidentified essential compounds not provided by the metabolism of diatoms, or unknown diatom-derived toxins, were probably involved.
CICIMAR Oceánides, 2009
This study experimentally determined the role of local diatom and dinoflagellate diets and theirfatty acid composition on the survival, ingestion, and egg production rates of the copepod Centropages furcatus from Bahía de La Paz. The fatty acid profiles of the diatoms Odontella longicruris and Chaetoceros sp., and of the dinoflagellates Scrippsiella sp., Gyrodinium sp., and Prorocentrum micans were determined. After incubating at 24 °C in darkness during 24 h, survival within all phytoplankton diets was > 90%. Dinoflagellate diets provided higher egg production (>25 eggs female-1 day-1) than diatom diets (<10 eggsfemale-1 day-1). No significant differences were observed in the ingestion rates when fed dinoflagellates or diatoms, which varied between 400 and 900 ng C copepod-1 h-1. Higher egg production with dinoflagellate diets suggests better food quality, which may be attributed to higher proportions of the fatty acids 18:4 (n-3) and 22:6 (n-3). These results suggest that...
Journal of Plankton Research, 1995
Copepod grazing on the toxic dinoflagellate Dinophysis acuminata from the west coast of France (La Rochelle) was studied with a concentrated (40-70 u.m) phytoplankton assemblage dominated by Leptocylindrus danicus, D.acuminata, Ceratium fiisus and Ceratium furca. Copepod nauplii were also present. Three to five copepods/copepodites (Acartia clausi, Isias clavipes and Centropages typicus) were incubated together with the phytoplankton. Dinophysis acuminata was grazed upon by all copepod species. However, to some extent, I.clavipes and C.typicus avoided it as food. Dinophysis acuminata cells represented for them only 5-10% of total ingested carbon during the first 24 h, and almost all individuals survived and thrived well. In contrast, A.clausi did not avoid D.acuminata, which represented 30% of ingested carbon in 1 day. Acartia clausi then had a lower survival than the two other copepod species. However, the survival of A.clausi was high in control incubations, where a plankton community without D.acuminata was used as food. It is concluded that the okadaic acid of D acuminata is potentially toxic to some grazers, and/or might function as an allelopathic grazer repellent. © Oxford University Press 1925 at Lunds Universitet on March 17, 2014 http://plankt.oxfordjournals.org/ Downloaded from P.Carlsson el al.