The effects of several common anthropogenic contaminants on proliferation of the parasitic oyster pathogen Perkinsus marinus

Abstract

Estuarine contaminants have varying effects on estuarine inhabitants and host-parasite interactions. Some field collected contaminant mixtures have been shown to increase oyster susceptibility to parasitism by Perkinsus marinus, but little is known about contaminant effects on the parasite itself. This study examined the effects of ammonium, nitrate, phosphate, fluoranthene, phenanthrene and a common herbicide mixture (Weed-B-Gone Ò ) on in vitro proliferation of P. marinus. Only the herbicide had a significant effect, but not at or below the manufacture's recommended application rate (7.81 ll ml À1 ). The herbicide's active ingredients (3.1% 2,4-dichlorophenoxyacetic acid, 10.6% mecoprop and 1.3% dicamba) mimic growth hormones of broadleaf plants; over stimulation of growth results in death. The mode of action of these compounds on P. marinus warrants further investigation which may provide insight towards the identification of biocides to control P. marinus.

Water-Quality Parameters and Total Aerobic Bacterial and Vibrionaceae Loads in Eastern Oysters (Crassostrea virginica) From Oyster-Gardening Sites

“…Other threats to oyster populations include diseases caused by the protozoan parasite Perkinsus marinus, commonly known as ''dermo,'' and Haplosporidium nelsoni, which is also known as ''MSX'' (Ragone Calvo et al 2003). Estuarine contaminants have negatively impacted oyster populations, thus compounding the effects of disease by increasing susceptibility to parasitism (Bushek et al 2007).…”

Associations between land use and Perkinsus marinus infection of eastern oysters in a high salinity, partially urbanized estuary

“…Attributing causality to postulated associations between infection prevalence and distance to land use is complicated because investigators have not quantified whether anthropogenic influences will have relatively greater deleterious effects on P. marinus or on eastern oysters (Bushek et al 2007). However, the apparent seasonal patterns seen in the prevalence-land use associations in the current study may most easily be explained by minor, seasonal changes in salinity and temperature gradients: Salinity and temperature levels are generally positively associated with P. marinus infection levels in oysters (Andrews 1988).…”

Binding of dicamba to soluble and bound extracellular polymeric substances (EPS) from aerobic activated sludge: A fluorescence quenching study

“…Because dicamba is highly soluble in water and extensively used in agriculture, it can easily enter the aqueous environments. It has been frequently detected in the surface water and ground water [12,13]. Dicamba is known to have toxic effects on aquatic plants and genotoxicity to animals [11].…”