An assessment of the effects of diatoms on planktonic copepods

Paffenhöfer, Gustav‐Adolf

doi:10.3354/meps227305

Cited by 45 publications

(21 citation statements)

References 23 publications

(34 reference statements)

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“…The focus of most of these studies was the effects of different algae on copepod performance. With regard to diatoms, monospecific diatom cultures have been shown to induce variable effects on copepod egg production and hatching (Jónas-dóttir & Kiørboe 1996, Ban et al 1997, Paffenhöfer 2002, ranging from being an excellent food source to being detrimental for copepods. The main issue is that in many studies it is not clear whether, or under which conditions, reduced egg production and hatching rates are due to toxins (e.g.…”

Section: Main Contributors: D Müller-navarra and S Jónasdóttirmentioning

confidence: 99%

“…Briefly, a body of evidence (reviewed by Paffenhöfer 2002 indicated that ingestion of some diatom species by females of some calanoid species could decrease their reproductive success due to the presence of teratogenic, or reproductioninhibitory chemicals in these diets. Unsaturated aldehydes (the term 'aldehyde(s)' is used in the text as an abbreviation to cover biologically active α,β,γ,δ-or α,β-unsaturated aldehydes) in some diatom species inhibited mitosis in developing copepod eggs and sea urchin embryos (Miralto et al 1999), and induced abnormal development of copepod nauplii in both the laboratory , Carotenuto et al 2002 and in the sea during periods of diatom abundance (Laabir et al 1995a, Ianora et al 2004.…”

Section: Main Contributors: J T Turner and G S Kleppelmentioning

confidence: 99%

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Colloquium on diatom-copepod interactions

Paffenhöfer¹,

Ianora²,

Miralto³

et al. 2005

Mar. Ecol. Prog. Ser.

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From 3 to 6 November 2002, a colloquium was convened at the Benthos Laboratory of the Stazione Zoologica Anton Dohrn on Ischia, Italy, with the goal of evaluating the present status of the effects of diatoms on their main consumers, planktonic copepods, and to develop future research strategies to enhance our understanding of such interactions. These included (1) toxic effects of diatom metabolites on copepods, particularly reproduction, and (2) nutritional effects of diatoms on juvenile to adult copepods. Key issues involved in the impact of diatoms on the dynamics of natural plankton communities in situ were also addressed. During the plenary session, the most recent advances on this topic were presented. The plenary session was followed by 3 working groups on (1) production of aldehydes by phytoplankton, (2) toxic and nutritional effects of diatoms on zooplankton, and (3) the chemistry of diatom defense, as well as of their nutritional quality. These working groups focused on suggesting future research needs for the different topics. As a result, several recommendations were outlined, including experimental studies. It became evident that interdisciplinary efforts are needed, involving chemists, oceanographers and experimentalists, since many of the biological observations under controlled conditions and in situ require an integrated approach, including chemical causation. Extensive field observations based on common protocols are also recommended for investigation of the intrinsic variability of such effects and their environmental controls. Laboratory experiments are seen to be essential for the full understanding of environmentally occurring processes.

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Section: Main Contributors: D Müller-navarra and S Jónasdóttirmentioning

confidence: 99%

Section: Main Contributors: J T Turner and G S Kleppelmentioning

confidence: 99%

Colloquium on diatom-copepod interactions

Paffenhöfer¹,

Ianora²,

Miralto³

et al. 2005

Mar. Ecol. Prog. Ser.

Self Cite

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“…Since 1994, there have been a number of laboratory studies examining the viability of copepod progeny when females are fed different food types, and many of these studies suggest that diets high in diatoms can reduce reproductive success compared to diets with alternative or mixed prey types (see reviews in Paffenhofer 2002;Ianora et al 2003). This phenomenon has been termed the ''diatom effect' ' (cf.…”

mentioning

confidence: 99%

The lost generation of Calanus pacificus: Is the diatom effect responsible?

Pierson

Frost

Leising

2007

Limnology & Oceanography

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An apparent mismatch between periods of high reproduction (spring) and high copepodite abundance (autumn) has been observed for the copepod Calanus pacificus in Dabob Bay, Washington, U.S.A. This persistent pattern leads to a lost generation of progeny that are produced in spring but do not recruit to the juvenile and adult populations, and this is likely due to a combination of factors including advective losses, predation mortality, and nonviability of progeny. Here we test the hypothesis that observed detrimental effects of diatoms on the viability of copepod embryonic and naupliar stages (the diatom effect) are the primary reason for the observed patterns of reproduction and abundance. Furthermore, we test how assumptions about egg production rate and naupliar viability can affect calculations of copepod recruitment. To test these hypotheses, we developed a numerical model to quantitatively explore how certain parameters may have affected the population of C. pacificus population in Dabob Bay. Predation mortality was the most significant contributor to population losses, while advective losses and naupliar viability were of lesser importance, and the model results were more sensitive to parameterization of naupliar viability than egg production rate. Although brief instances of low naupliar viability caused a 25-30% reduction in cumulative stage I copepodite abundance over time when compared with the assumption of persistent high naupliar viability, the lost generation of C. pacificus in Dabob Bay is likely due to predation mortality, not the diatom effect.

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“…Toxicity of various species of phytoplankton can have a great impact on the copepod community (Turner et al 1998;Frangoulos et al 2000;Schmidt et al 2002). Several diatoms have proven to have negative impacts on copepod fecundity and egg viability (reviewed in Paffenho¨fer 2002;Ianora et al 2003). The exact causes of these negative impacts are still under discussion, both toxicity as well as nutritional deficiency have been invoked.…”

Section: Introductionmentioning

confidence: 99%

Impacts of copepods on marine seston, and resulting effects on Calanus finmarchicus RNA:DNA ratios in mesocosm experiments

et al. 2004

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We investigated the impact of copepods on the seston community in a mesocosm set-up, and assessed how the changes in food quantity, quality and size affected the condition of the grazers, by measuring the RNA:DNA ratios in different developmental stages of Calanus finmarchicus. Manipulated copepod densities did not affect the particulate carbon concentration in the mesocosms. On the other hand, chlorophyll a content increased with higher copepod densities, and increasing densities had a positive effect on seston food quality in the mesocosms, measured as C:N ratios and x3:x6 fatty acid ratios. These food quality indicators were significantly correlated to the nutritional status of C. finmarchicus. In contrast to our expectations, these results suggest a lower copepod growth potential on higher quality food. However, in concordance with earlier studies, we found that when copepods were in high densities the large particles (>1000 lm 3 ) decreased and that the smaller particles (<1000 lm 3 ) increased in number. These patterns were closely linked to the condition of C. finmarchicus, which were of better condition (RNA:DNA ratios) with increasing biovolumes of large particles, and, conversely, lower RNA:DNA ratios with increasing biovolumes of smaller particles. Consequentially, the selective grazing by copepods stimulated increased biovolumes of smaller plankton, and this increase was responsible for the increased food quality, in terms of C:N and x3:x6 ratios. Thus, we conclude that the decreasing growth potentials of C. finmarchicus were a result of a decrease of favourably sized food particles, induced by copepod grazing.

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An assessment of the effects of diatoms on planktonic copepods

Cited by 45 publications

References 23 publications

Colloquium on diatom-copepod interactions

Colloquium on diatom-copepod interactions

The lost generation of Calanus pacificus: Is the diatom effect responsible?

Impacts of copepods on marine seston, and resulting effects on Calanus finmarchicus RNA:DNA ratios in mesocosm experiments

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