Trace Metal Homeostasis and Toxicity

Lymnena snail and egg sacs in a tank within the lab Lymnena snail and egg sacs in a tank within the lab
Lymnena snails and their egg sacs in a tank within the lab Lymnena snails and their egg sacs in a tank within the lab
Lymnena snail in tank Lymnena snail in tank
Lymnena snails and their egg sacs in a tank within the lab Lymnena snails and their egg sacs in a tank within the lab
Homeostasis, deficiency, or toxicity of essential trace metals is often a very fine balance and many trace metals, essential and non-essential, are potent toxicants to aquatic organisms. Metal toxicity is influenced greatly by water chemistry which contributes significantly to apparent differences in sensitivity among studies. However, perhaps the greatest contributor to variation is interspecies differences, which can range by three orders of magnitude for a given metal (Grosell 2011). Our focus has been on what accounts for these large differences in sensitivity among species. Although exceptions exists, it appears the >90% of variation in sensitivity to copper and silver among freshwater organisms is related to Na+ turnover rates, which again are strongly correlated to organismal size (Grosell et al, 2002). For marine organisms, size and developmental stage also appears to contribute significantly to variation in sensitivity. However, osmoregulatory strategies (conformers versus regulators) play a key role in determining sensitivity (Grosell et al 2007). The interplay between osmoregulatory strategies and salinity in estuaries offers an interesting challenge for scientist wishing to predict metal sensitivity based purely on water chemistry.