Effects of Karenia brevis diet on RNA:DNA ratios and egg production of Acartia tonsa

Speekmann, Christa L.; Hyatt, Cammie; Buskey, Edward J.

doi:10.1016/j.hal.2006.03.002

Cited by 25 publications

(22 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Prey selection results do favor the conclusion that K. brevis is either toxic or not a sufficient food for grazers, a fact supported by our results and many other studies (Collumb & Buskey 2004, Speekmann et al 2006, Breier & Buskey 2007. Low to negligible grazing rates on monoalgal diets of K. brevis have been documented repeatedly for A. tonsa populations from the GOM (Collumb & Buskey 2004, Speekmann et al 2006, Breier & Buskey 2007. These low grazing rates were coupled with reduced egg production rates similar to starved copepods, further supporting the conclusion that K. brevis is not a nutritionally viable food source, or is toxic.…”

Section: Grazing On Karenia Brevissupporting

confidence: 90%

“…Turner & Tester (1989) found that during a rare bloom event off the North Carolina coast, the cooccurring copepod species Acartia tonsa, Oncaea venusta, and Labidocera aestiva all consumed K. brevis at rates increasing with cell concentration, while Centropages typicus and Paracalanus quasimodo ceased grazing; however, in prey selection experiments, A. tonsa, L. aestiva, and C. typicus all selected against K. brevis in favor of consuming Skeletonema costatum. Prey selection results do favor the conclusion that K. brevis is either toxic or not a sufficient food for grazers, a fact supported by our results and many other studies (Collumb & Buskey 2004, Speekmann et al 2006, Breier & Buskey 2007. Low to negligible grazing rates on monoalgal diets of K. brevis have been documented repeatedly for A. tonsa populations from the GOM (Collumb & Buskey 2004, Speekmann et al 2006, Breier & Buskey 2007.…”

Section: Grazing On Karenia Brevissupporting

confidence: 88%

“…First, the biogeographic source of the experimental copepod population may factor into the observed responses. Experiments using copepod populations from the western GOM repeatedly show no significant mortality, yet show low egg production and grazing rates on monoalgal diets of Karenia brevis, with high grazing on mixtures of K. brevis and a nutritious algal species (Collumb & Buskey 2004, Speekmann et al 2006, Breier & Buskey 2007. These populations experience more frequent exposure to K. brevis blooms than counterparts from the US SAB.…”

Section: Grazing On Karenia Brevismentioning

confidence: 99%

“…Additionally, competition experiments have demonstrated that K. brevis is avoided by most grazers. Multiple copepod species have been found to discriminate against K. brevis based on their toxin content, and lower reproductive and ingestion rates have been found for copepods fed diets dominated by K. brevis (Huntley et al 1986, Speekmann et al 2006, Breier & Buskey 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Conflicting evidence currently exists within the literature regarding the role of brevetoxins as grazing deterrents. While some research suggests that copepods avoid consuming K. brevis due to its nutritional inadequacy (Collumb & Buskey 2004, Speekmann et al 2006, Breier & Buskey 2007, other reports offer support that toxins are the cause of this avoidance (Huntley et al 1986, Cohen et al 2007). Recent studies offer convincing evidence that K. brevis is a low quality food for copepods, particularly Acartia tonsa, one of the dominant zooplankters found within blooms of K. brevis (Lester et al 2008).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Toxicity and nutritional inadequacy of Karenia brevis: synergistic mechanisms disrupt top-down grazer control

Waggett¹,

Hardison²,

Tester³

2012

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Zooplankton grazers are capable of influencing food-web dynamics by exerting topdown control over phytoplankton prey populations. Certain toxic or unpalatable algal species have evolved mechanisms to disrupt grazer control, thereby facilitating the formation of massive, monospecific blooms. The harmful algal bloom (HAB)-forming dinoflagellate Karenia brevis has been associated with lethal and sublethal effects on zooplankton that may offer both direct and indirect support of bloom formation and maintenance. Reductions in copepod grazing on K. brevis have been attributed to acute physiological incapacitation and nutritional inadequacy. To evaluate the potential toxicity or nutritional inadequacy of K. brevis, food removal and egg production experiments were conducted using the copepod Acartia tonsa and K. brevis strains CCMP 2228, Wilson, and SP-1, characterized using liquid chromatography-mass spectrometry (LC-MS) as having high, low, and no brevetoxin levels, respectively. Variable grazing rates were found in experiments involving mixtures of toxic CCMP 2228 and Wilson strains. However, in experiments with toxic CCMP 2228 and non-toxic SP-1 strains, A. tonsa grazed SP-1 at significantly higher rates than the toxic alternative. Additionally, A. tonsa experienced significantly greater mortality when exposed to toxic K. brevis strains, particularly after prolonged exposure. Egg production rates of copepods fed toxic K. brevis strains were similar to those of starved copepods, while those of copepods fed non-toxic SP-1 and the nutritious Rhodomonas salina were significantly higher. Analysis indicates that K. brevis impacts grazer populations via multiple synergistic mechanisms: (1) decreased ingestion rates, (2) decreased egg production, and (3) increased mortality of copepods through a combination of toxicity and nutritional inadequacy.

show abstract