Skip to main content

A Review on Horseshoe Crab Development During Exposure to a Variety of Pollutants

     Pollutants are known for their effects on development and growth of living organisms. I became curious as to what effects they have on different marine arthropods and how they affected development, and that was how I stumbled upon a chapter by Mark L. Botton and Tomio Itow. The book covers horseshoe crab biology and conservation, but the chapter that I read focused on how pollutants affected the development of horseshoe crab embryos and larvae. 

    The chapter addresses how horseshoe crab populations across the world are declining, and one of the reasons could be pollution. The chapter looks at multiple different studies that were done on different horseshoe crab species and how their development was affected by certain pollutants, and the results were shocking to me. Horseshoe crab are pretty resilient to pollutants all around. Most pollutants had little effect on horseshoe crabs which didn't make much sense to me. Of course, they found that as exposure to pollutants increased, survival decreases, but the level that the pollutants had be at to affect survival was high. 

    One of the main pollutants discussed in the chapter is heavy metals which is known to affect marine arthropods' survival especially during early development. However, horseshoe crabs, especially their larvae, were found to be able to survive at extremely high levels of certain heavy metals. Embryo development was effected by these metals, though, and many embryos had abnormalities after exposure. If a female horseshoe crab has been exposed to heavy metals, she can pass those pollutants to her eggs. These eggs have a very low survival rate, and they developed slowly with multiple abnormalities. 

    The chapter also looked at the affects of oil pollution which had even stranger results. Oil could have detrimental affects on horseshoe crabs which is what is expected, but if the oil is at a certain concentration, there is a higher hatching success. 

    Horseshoe crabs are also able to survive in a wide range of temperature and salinity conditions. The best temperature for development of horseshoe crabs is 25 to 33C, but when exposed to higher temperatures for short periods of time, it had no affect on their survival rate. Horseshoe crabs also develop the best when salinity concentrations are between 20-40%. When salinity was increased or decreased, there was also no change in survival rates, but instead, development took longer. 

    I found it fascinating how these organisms were able to tolerate such high levels of pollutants, and some pollutants had very little affect on their development depending on what stage of development they are at. It is amazing how horseshoe crabs can also survive in such a wide range of environmental conditions. The chapter contributes the horseshoe crab ability to survive in different environments to the production of stress protein, but it also mentions how more research needs to be done to totally understand horseshoe crab pollutant tolerance. However, seeing how high of tolerance that horseshoe crabs have against pollutants, it is believed that pollutants may not be the reason for declines in their populations. 


Source:

Botton M.L., Itow T. (2009). The Effect of Water Quality on Horseshoe Crab Embryos and Larvae. In: Tanacredi J., Botton M., Smith D. (Eds.), Biology and Conservation of Horseshoe Crabs (439-454). Springer, Boston, MA. https://doi.org/10.1007/978-0-387-89959-6_27

    

Comments

  1. Jake WarrenApril 26, 2021 at 7:35 PM

    Jenny, I have always enjoyed readings on arthropods, especially those integral to shorebird species. You highlighting the resilience that horseshoe crabs show raises an interesting idea. With these organisms showing resilience to these pollutants and their species persists despite high pollution levels, what happens to shorebirds that rely on their eggs?

    When it comes to persistent bio-pollutants, typically the mother can pass these bio-affecters to their offspring. With these eggs possibly containing remanence from the mother's own bioaccumulation, I can only hypothesis how that might persist to the trophic levels that rely on theses eggs as food. Thank you for the thought provoking article!

    ReplyDelete

Post a Comment

Popular posts from this blog

The Environmental Trade-offs of Increased Antidepressant Use

       I came across an interesting sentiment the other day. In response to the generational expression  “kids have it so easy nowadays” someone replied “that’s the point”. The point of progressing is to make life easier for the next generation. While today’s kids don’t have to walk uphill both ways to get to school, they face their own unique obstacles with the constant pressures from social media and threat of school shootings. The 2021 State Of Mental Health In America survey reports that youth depression is worsening. Statistics show that this disproportionately affects youths who identify as more than one race. However, some statistical growth can be attributed to an increase in diagnoses as the stigma of mental health has changed and more people seek treatment. Along with better access to therapy, access to a variety of antidepressants has increased as well. The CDC reports that from 1999 to 2014 antidepressant use has increased by almost 65% with one in...
Post a Comment
Read more

Are ecotoxicologists going to the dogs? No...but they should.

A few months ago I read an article about the Miami Heat basketball organization using Covid sniffing dogs to admit fans into the arena and was blown away. They can't actually detect the virus, but they can pick up the chemical differences in the composition of breaths exhaled between healthy and infected individuals (Dorman 2021). I've always heard about dogs being used to detect drugs and track fugitives, but the ability to detect a virus by sniffing a person's breath is just on a whole other level. I started thinking about possible applications and the idea of using dogs to detect pollutants in the environment came across my mind.  While researching the capabilities of these sniffing dogs, I searched for any examples or projects that involved using sniffing dogs as pollutant detectors and I came across an EPA proof of concept from 2003. The idea was to train sniffing dogs to be able to detect various environmental contaminants that range from house molds to illegal pestic...
4 comments
Read more

Does developmental environment influence timing of life-history events?

Most of ecotoxicology focusses on immediate effects contaminants have on organisms, drawing conclusions about what this may mean for fitness based on traits like size. However, some negative effects may be unnoticed. For example, transgenerational effects may not impact the exposed generation, but those organisms may produce offspring with lower fitness. This has been shown in beetles exposed to pesticides, where the offspring of an exposed parent had reduced fitness due to transgenerational effects (Baker et al. 2019). Similarly unnoticed, and even further neglected, is how conditions during development may alter the timing of life history events. How do gene x environment interactions influence timing of sexual maturation? Or age at first reproduction? Or even number of offspring during each reproductive event? Many of these questions are unanswered as most research terminates studies well before reproduction, likely due to long generation times and/or cost of maintaining animals. Ad...
1 comment
Read more