Amanda Kahn

Name: Amanda Kahn, graduate student

Hometown: Fremont, California, USA
Home university: University of Alberta
Previous degrees: BS Biology and BA Chemistry, California State University, East Bay.  MS Marine Science, Moss Landing Marine Laboratories/California State University, Monterey Bay

I study marine sponges, which are animals that filter food out of the water.  Glass sponges are a particular group of sponges that mostly inhabit the deep sea, but live in shallow waters in just a few locations in the world.  Not only does the coast of Western Canada support shallow glass sponges, but those sponges can grow on the fused skeletons of previous generations, forming reefs the same way that coral reefs are formed.  SO COOL!  Sponges used to form reefs until the Jurassic, but in present day these are the only reefs that have been found so far.  Since they’re such a unique habitat, some reefs might be protected by Marine Protected Areas in the future.

Trawling, a form of fishing that drags a net along the seafloor, is a threat to these reefs in a few different ways: it can scrape over the sponges, scooping them up or breaking them and killing them, or it can kick up sediment that clogs the filter system (called the aquiferous system).  I’m studying how much energy it takes a sponge to survive, meaning what it needs to just maintain itself at its current size, and will compare that to how much food the sponges can pull from the water.  If sponges are just barely squeaking by with the food they’re exposed to, then the sediment that reduces their filtering ability may tip the balance from survival to a slow decline in health.  My supervisor and I study the sponges by going out to sea on ships and using ROPOS, a big, remote-controlled submersible.