you're reading...


Do pesticides negatively affect moon jellyfish?

Reference: Polyps of the Jellyfish Aurelia aurita are unaffected by chronic exposure to a combination of pesticides.
Olguin-Jacobson, C., Pitt, K.A., Carroll A.R., and S.D. Melvin. 2020. Environmental Toxicology 39(9): 1685-1692.
https://doi: 10.1002/etc.4750

Pesticides: intended and unintended effects

Pesticides are a common product used to control pests. They can be targeted to control pest plants (herbicides), insects (insecticides), or fungi (fungicides). It’s estimated that the United States applies one billion tons of pesticides annually. Pesticides as a group have made it possible to produce food without worrying about crops being destroyed or damaged by other organisms, however, there can be unintended effects of pesticide use.


Industrial farms often use tons of pesticides in order to control pest populations and increase crop production. By Einboeck.official – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=95853158

Toxic pesticide to be sprayed on crops. By Unknown author – United States Department of Agriculture (USDA) – http://www.usda.gov/oc/photo/94cs3568.htm, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1705629







Target organisms (or the animal or plant the pesticide is designed to affect) are often not the only organism impacted; nontarget organisms are often affected too. Pesticides can attack biological pathways that are similar across many plant and animal species. Pesticides can also seep into groundwater or wash into freshwater or marine waterways, affecting aquatic species.

Jellyfish: a good test species?

One common model species often used to investigate how anthropogenic (human-caused) stressors affect marine species is the moon jellyfish, Aurelia aurita. Many scientists believe that these jellyfish are less affected by stressors, both anthropogenic and natural. While they are native to coastal waters around the world they are also highly invasive, most likely due to their ability to tolerate a variety of stressors. But the moon jellyfish has also been shown to be sensitive to pollutants like crude oil, other chemicals, and heavy metals, so they may be affected by pesticides as well.

Jellyfish have two different life stages: a polyp stage, which is attached by a stalk to the bottom of the ocean and reproduces asexually by budding, and a medusa stage, or what most people think about when they picture a jellyfish. The polyp stage of jellyfish may be more susceptible to contaminants, since it’s attached to the bottom and can’t swim away. If pesticides wash into the water and end up near the seafloor, these polyps can be directly exposed. Therefore, this study looked at whether or not jellyfish polyps were affected by exposure to a few different types of pesticide.

The Medusa stage of moon jellyfish. By Cliff from Arlington, Virginia, USA – Moon Jellies (Aurelia aurita)Uploaded by Magnus Manske, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=22968172

The experiment

Several previous experiments have looked at how pesticides affect jellyfish. However, these studies used only a single pesticide at very high concentrations, for a short period of time (5-7 days), or what’s called an acute exposure. While this is valuable, it’s more likely that jellyfish in the oceans are exposed to very low levels of multiple different types of pesticides, for an extended period of time- what’s known as a chronic exposure.

Scientists at Griffith University in Australia therefore exposed moon jellyfish polyps to either atrazine, a common herbicide, chlorpyrifos, a common insecticide, or both. They attached polyps to small petri dishes and immersed the petri dishes in glass beakers filled with seawater and a known concentration of pesticide. They used low concentrations (0.04 micrograms per liter for chlorpyrifos and 2.5 micrograms per liter for atrazine) that fell below the Australian water quality guidelines. The researchers then examined whether exposures killed any of the polyps, the number of asexual buds each polyp produced, and the composition of polar metabolites- things like amino acids, nucleic acids, and sugars, that play a role in important biological pathways.


Results: where do we go from here?

At the end of the experiment, surprisingly, all polyps had survived and there was no difference in the number of asexual buds between treatments. There was also no difference in the polar metabolites, indicating that these pesticides didn’t affect important biological processes.

According to the researchers, it’s possible that the pesticides didn’t affect moon jellyfish polyps because jellyfish are neither plants nor insects- and therefore not the target for the herbicide atrazine or the insecticide chlorpyrifos. It’s possible then that moon jellies could be affected by other pesticides that work differently, or that they’re just a particularly hardy species that can tolerate many stressors.

However, not all jellyfish species are moon jellies. Just because moon jellyfish seem to be resilient to these pesticides doesn’t mean all jellyfish are. The researchers emphasize that there is a need to understand how the full range of pesticides that can get into the world’s oceans affect many different species of jellyfish, not just one. With about 5.6 billion tons of pesticides used globally each year (1 billion tons of that coming from the U.S alone), there is a definite need to investigate how these contaminants may be affecting not just wildlife, but human health as well.





No comments yet.

Post a Comment


  • by oceanbites 3 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 4 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 5 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 6 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 9 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 9 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 10 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 10 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 11 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 11 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 12 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 1 year ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com