The escape response to fluid mechanical signals was examined in 6 protists, 4 ciliates and 2 dinoflagellates. When exposed to a siphon flow, 3 species of ciliates, Balanion comatum, Strobilidium sp., and Mesodinium pulex, responded with escape jumps. The threshold deformation rates required to elicit an escape ranged between 1.8 and 3 s–1. Escape speeds varied between 100 to 150 body length s–1...

Heterocystous, planktonic cyanobacteria capable of fixing atmospheric N2 into available nitrogen (N) are common and critically important to nutrient cycling in many lakes, yet they are rarely observed in estuaries at salinities >10 ppt, even when strongly N limited. In a series of mesocosm experiments using water from Narragansett Bay (Rhode Island), we manipulated top-down (grazing) and bottom...

1. During a study of five artificial brackish ponds situated in Doñana Natural Park and the Guadalquivir delta between July 2001 and June 2002, a total of six copepod species (two calanoids, three cyclopoids and one harpacticoid) were recorded. All of them are typical of brackish or estuarine habitats. 2. The estuarine calanoid copepod Acartia tonsa (originally from North America) was present i...

In this study we hypothesized that the sexes of the copepod Acartia hudsonica experience different mortalities when exposed to the toxic dinoflagellate Alexandrium fundyense. In laboratory experiments, we manipulated toxin dose and measured sex-specific mortality. We also used a split-family design to determine whether there were genetic influences on sex determination, and therefore on sex rat...

Copepods can feed on, and may regulate, the blooms of harmful algae (HA), also facilitate dinoflagellate by inducing toxin production through selective grazing. However, exposure to HA cause mortality reproductive impairment in copepods, with detrimental effects at population-scale. Here we present profile dinoflagellate, Alexandrium catenella (formerly tamarense ), examine how it affects survi...

As dominant members of marine mesozooplankton communities, copepods play critical roles in oceanic food webs and biogeochemical cycling. Despite the ecological significance of copepods, little is known regarding the causes of copepod mortality, and up to 35% of total copepod mortality cannot be accounted for by predation alone. Viruses have been established as ecologically important infectious ...