Nobody is Shocked That a DC Swamp is Home to a Spineless Creature

Washington D.C. probably has the largest collection of spineless creatures anywhere in the world. But the public servants representing you in government were not harmed for the purposes of this study. Researchers sampled an actual Washington DC swamp and found a spineless creature that is worth studying.

The Hay's Spring amphipod is strikingly similar to an elected official in Washington. They look nothing alike but are described exactly the same. Spineless and lacking vision, the creature is an opportunistic feeder, consuming whatever resources are available including the remains of its own kind.

Put a red tie and a sense of entitlement on this thing and it may end up getting its own super PAC. 

This particular species lives only in Rock Creek Park and, because of its small and declining numbers, is on the U.S. endangered species list. 

"Yes, it's small, it's white, it's eyeless, it lives underground," said Mathew Niemiller, an ecologist with the Illinois Natural History Survey.  "It's not a cute, cuddly or charismatic species. But we're still learning more and more about groundwater ecosystems. And there is evidence that these crustaceans are important indicators of groundwater quality, and may play important roles in water purification and nutrient cycling over time."

As with any species that need to be studied, amphipod or politician, if you are going to get to know them, you are going to have to get down there in the muck with them. This proved to be a difficult conundrum considering the endangered status of the amphipod.

"And because these critters are small -- no more than a centimeter long -- and a couple of other species look very similar to S. hayi, we would have to sacrifice any individuals we find and take them back to the lab to identify them," he said. "Since this is an endangered species, that's something we don't want to do."

Instead, Niemiller and his colleagues used a process called eDNA. This is a scientific process of sampling the water where these anthropod live. The team then filtered the water on site and returned to the lab to sample the filters and see if any DNA of the S. hayi was left behind. All creatures will leave behind trace samples of their DNA in their environment. However it was not known whether the small creatures would leave behind samples big enough to be detectable by the DNA tests. eDNA has worked before to find larger animals, but had never been used to determine the presence of something this small. 

The team's processes were successful. Their samples returned positive for DNA of the species in three of the four sites wherer it had previously been spotted. 

"We now know that eDNA is going to be a really worthwhile tool - at least for aquatic species in difficult-to-access habitats," Niemiller said. "You could go to a spring outflow, take a water sample, and see what you might detect there with a limited outlay of labor, time and money. 

The eDNA process does have its limitations. For one, it only detects DNA. It does not tell the researchers how many of the species are likely to be living in any one particular area. Secondly, it does not actually confirm that the DNA from these species is from dead or alive organisms. The spring where the water was sampled could have remnants of dead organisms. This does not give the researchers an idea of how well the organisms are flourishing presently in any given ecosystem. 

While the Hay's Spring amphipod still lives in Rock Creek Park, it remains on the endangered species list. As far as I know, all things spineless, white and with no vision will continue to exist in Washington DC. You don't need an eDNA test to tell you that.