Hunting for microbes while exploring Block Island’s salt marsh ecosystems


Scott Chimileski Block Island Rose hip

Rose hip flowers can be found throughout Block Island’s dunes.

I have been going on vacation on Block Island every summer since I was a child. Block Island is small, only a few miles wide, and sits just 12 miles off of the coast of Rhode Island. Despite its size, the island is a robust habitat for many plants and animals, surrounded by a coastal marine ecosystem, dotted with over 300 freshwater ponds, and innervated by a system of brackish marshland.


Looking down at the bottom of the salt marsh.

I have spent over 6 months of my life here combined, but every time I get off the ferry, and I begin to explore the island’s various habitats, I have a renewed sense of wonder.  One of the first things you see and hear are the birds. The island is an oasis for rare birds and they are everywhere, ducking in and out of the dense shrub-filled landscape. They seem especially happy, most of the time blasting higher with 3 or 4 wing beats, and then free falling, over and over again as they hunt for bugs. There are also beautiful bright rose hip flowers, countless odd and colorful insect species, and of course purple starfish and marine creatures of all kinds.

Scott Chimleski Block Island

Underwater photography in the Great Salt Pond.

But this year I want to look into these ecosystems a bit further. I am intrigued by the unseen microbial layer at the base of every ecosystem. What do the microbes of Block Island soil, water and air look like?

Scott Chimileski

Colonies formed from salt marsh mud.

Well, here is a quick survey. These colonies appeared after two days at room temperature. The plate was inoculated with a sample of marsh mud I collected while kayaking with my sister along the edge of the salt marshes of Great Salt Pond. Beneath the kelp, the sediment at the bottom was dense and littered with seashells.

Scott Chimileski

An unseen universe of microbes. The side of a rock removed from the salt marsh mud. My camera is collecting an underwater time-lapse sequence in the background.

Of course, this is mere glimpse into the microbial diversity of this sample.  But it is beautiful nonetheless.  After every corner that we kayaked around there was a heron stalking through ankle deep water, appearing truly like the dinosaurs of this land.  I thought to myself, how large is this heron, and how small the millions of microbes that themselves stalk the mud beneath the heron’s feet. What amazing dimensions of life layer our visible world.