Wormy Waters

If you have a dog you know roundworms as the bad guys. In fact over half of the known species of roundworms are parasitic. But they aren’t always the bad guys. Jyotsna Sharma, a marine ecologist, studies the “good” species of roundworms. She uses roundworms as a bio indicator, an organism that scientists can study to see how healthy an ecosystem is. She is currently looking at roundworms found in the sediment of the Gulf, to see how the populations change before and after an oil spill. Before she was at UTSA she also studied similar populations on the west coast of Canada, and North Sea estuaries, as well as worms found in the skin folds of Stink Pot turtles.

Oil Spills

Round worms constitute the entirety of the phylum Nematoda. Some claim that these small worms constitute 90% of life on the ocean floor. The Deepwater Horizon Oil Spill in 2010 dumped 4.9 million barrels of oil into the Gulf of Mexico. We all saw the pictures of shores covered in oil, dead fish, and oil smothering sea birds. The work Jyotsna Sharma does set out to prove that the smaller organisms were affected as well. Even if the animals were microscopic and mesoscopic they are still important because of their roles in marine ecosystems.

The research teams gathered samples from the sediments of shorelines heavily hit by the oil spills. They not only compared what species were prevalent but also marker genes and morphological characteristics of some species. Before the oil spill, the animals were diverse and balanced. After the oil spill fungal populations bloomed, many were hydrocarbon-degrading fungi. After the oil spill many of the nematodes were predatory or scavengers, rather than a balance. The majority were also juveniles, suggesting that many of the adults had been killed off. Next Professor Sharma collaborated on a research paper discussing the recovery of nematode population recuperation after the oil spill. Her results showed that the population only started to gradually repair after 12 months. These results show that even after the physical signs of the oil spill were gone, it still had devastating impact on the ecosystem and organisms.

Fun Facts

When researching Professor Sharma’s work I learned a lot about these little worms, and I thought to share some fun facts about them.

  • Nematodes can be pretty scary. Some species of nematodes have a sharp stylet that they thrust into their prey. This tube appendage allows them to suck up the bodily juices, aka vampire worms.
  • Digestive enzymes are produced in the pharynx. If the species has a stylet these enzymes can be injected into their prey to start digesting it even before it’s in the worm’s mouth.
  • Nematodes have no stomach; the muscular pharynx connects directly to the intestine. The intestines have no muscles so the food is moved through the system propelled by the worm’s bodily movement.
  • Nematodes are found in every part of the world, marine, freshwater, polar, topical, soil, from the tops of mountains to oceanic trenches. Nematodes were even found 3.6 kilometers (over two miles) underground.
  • A species of giant nematodes live in the stomach of sperm wales and can grow to 8 meters long.


If you want to check out Jyotsna Sharma’s work here are the links to research papers:

I would also like to thank Ms. Sharma for talking to me about her research, and allowing me to post this article.


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