By John Tapley
Porous, amorphous, and harmless, sponges have been an integral part of Earth’s evolutionary system since their primordial beginnings hundreds of millions of years ago. Despite popular understanding, not all sponges are bound to pineapples under the tropical sea: from polar climes to brackish junctions to enclosed freshwater environments, sponges have spread throughout the entire globe. Freshwater types make up nearly 240 known species with 31 of these residing in North America; and a closer look reveals five types within Minnesota’s waterways. Monitoring, categorizing, and testing these specimens is the Minnesota Freshwater Sponge Project, which in recent months, has had great success confirming valuable findings of the past – and may be on to new discoveries in the future.
A program by the University of Minnesota Crookston, the project seeks to identify sponges, find new species if available, and share the importance of these ancient animals and their interconnectedness with the greater world. From surveys to genetic research, the three-year-long project also provides a significant boon to students studying biology.
“The University of Minnesota Crookston is a primarily undergraduate university,” explains Karl Anderson, researcher and teaching specialist for the university’s Math, Science & Technology Department. “A project like this is amenable for undergraduate students to get involved in: discovering something that hasn’t been described in a long time or finding something new… moving forward into genetic research and microbiology in discovering these organisms.”
While they may seem simple on a surface level, sponges play a critical role in aquatic environments: not only as filters for debris and detritus, but as housing for even smaller creatures. Freshwater sponges are especially resilient in comparison to their more colorful, tropical cousins: requiring them to withstand frigid Great Lakes temperatures. Mini, but mighty, these sedentary creatures can indicate good water health, and in turn, form a stronger and clearer aqua scape; and beyond the immediate ecosystem, their function ripples into the greater food web.
Anderson elaborates further:
“There is some research that attributes sponges to great water quality: when you see them, you probably have good, pristine waters – depending on what’s being filtered. Sponges, as poriferans in their classification, are described as organisms that have pores, which water goes through. It continues moving through them, and the sponge structure itself as well as other organisms that live in it, are removing different materials from the water. Think of them as a live filter for the environment: they remove microscopic debris in the environment, which can include chemicals.
“They’re really important in terms of a filter in certain environments, and also as a home for all sorts of other creatures. Their structure allows different microbes and invertebrates to live within, and that moves into the whole food web: smaller fishes are going to consume smaller invertebrates, algae, and bacteria in the sponge. It’s an important environmental relationship: from small fish to bigger game fish, and on to humans.”
From late summer to fall of this year, Anderson and company conducted an important mission: sampling “two major watersheds in Minnesota, half a dozen different lakes, and a dozen rivers”; and in turn, doing spicule analysis (observing shape and bony structures), and performing extractions for genetic testing. Their efforts were well worth the endeavor, as the team successfully confirmed findings from a University of Minnesota study conduced in the ‘70s and ‘80s: two sponges called Spongilla lacustris and Ephydatia muellerimake a home in Minnesotan waters.
While these findings shined as milestones for the project, a third, more mysterious discovery piques Anderson’s scientific curiosity, and he is excited to unveil these mysteries following the next expedition when waters and their spongy denizens warm up.
“[We] have found another genetic sequence from one of the samples that may be something that hasn’t been described in any research we have found so far: it might be something interesting; it might be a subspecies with subtle differences,” he explains. “Chemical analysis work is still in development, and we’re excited to move forward when we hit the water again in late spring and summer.”
As the project continues onward, the thrill of discovery and dedication of the local science community leading the way, Anderson is optimistic about future findings, and encourages others to help out. While a concrete system for citizen scientists to share their discoveries in tentative, the project is more than willing to receive helpful information from snorkelers and scuba divers. By contributing their time to the Minnesota Freshwater Sponge Project, volunteers may lead to a big breakthrough; and by corollary, encourage others toward scientific pursuits.
“This project has been a great learning experience all around for everybody involved: from citizen scientists to the freshman starting out in college,” says Anderson. “It’s been a great tool in getting others excited about learning. A lot of students are chomping at the bit to get involved in the project and see what we can do. We’re excited for what’s next.”
For more information on the Minnesota Freshwater Sponge Project, including contact information for interested citizen scientists, visitwww.freshwatersponges.crk.umn.edu