The HaloEd Project

A web site dedicated to biotechnology education

Wild in the Wetlands

Some of us remember visiting Fort McHenry in middle school when we were studying the War of 1812, but we didn’t remember wetlands. But then, most of us didn’t know what a wetland was until we took biology this year at Walter Johnson High School in Bethesda. Still the idea of a marsh in the middle of Baltimore seemed strange.

Our first stop at the visitors’ center to meet our hosts (Tammy Roberson from the National Aquarium and Priya DasSarma from COMB) didn’t reveal muck, but a short hike across a well-kept lawn and past some amazing monuments took us to a tall fence with a locked gate. At the bottom of a short flight of stairs, there it was, spread out in front of us. We looked cross an expanse of very unfamiliar plants sticking out of mud that ended at the open water of the Bay. It seemed unusual to look at such a wild and natural area and see it bordered by warehouses and smokestacks.

As we continued our tour to a sandy beach at the end of the saltwater marsh, volunteers of the Wetlands Project told us about the many migrating birds that stop over for food and shelter. They also taught us some of the plant names. As we climbed a hillside at the marsh edge, we recognized some old favorites, like black-eyed susans and crabapples.

But enough sight-seeing! We came here with work to do. Ms DasSarma is a microbiologist interested in identifying microbes that might be useful in combating pollution (like oil- or plastic-eating bacteria.) She works with an “extreme” microorganism, called halobacteria that prefers its home to be very salty. Since she has found this microbe in other parts of Maryland and since salt can become very concentrated in the soil of a marsh, we think it will be possible to find halobacteria here. Given that we are in a month-long drought, leaving the marsh in very unsoggy shape, we are even more hopeful. So we collected soil samples from two locations. Our first sampling site was in the upper marsh, which looks like it contains a lot of organic material and is very dark. Our second site in the lower marsh looks much more sandy. We also checked some of the physical characteristics of the soil, including pH and the presence of nutrients like phosphates and nitrates. When we get back to school, we plan to see if we can grow microbes on both solid and liquid nutrient media. The media will have a very high salinity (salt content) in order to promote the growth of halobacteria and discourage the growth of less extreme, and possibly toxic, organisms. We will know if we have found promising candidates if our colonies are pink, the color of halobacteria.

As one of its curators, Ms Roberson is interested in the overall health of the Fort McHenry Wetlands. To help her monitor this, we collected water samples from the shoreline and tested water quality (pH, phosphates, nitrates, dissolved oxygen, salinity). We are taking water back to school to create biofilms as a way to determine the biodiversity of the microlife in the wetlands. As a class, we are also interested in comparing the diversity of microlife in freshwater to salt water. So we are also making biofilms in samples taken from Sligo Creek, from both running water and a stillwater pond. We will inventory our results in about two weeks.

Pictures from our Field Trip:

Arrival at the site – Tammy from the National Aquarium tells us about the Fort site.

First sampling site – collecting the “muck”

Here’s my sample!

At the weather station.

Jim Peters, the Bird-specialist gave us a special treat – telling us all about the birds one can see out here!

Blue-bird nesting “gourds”.

Other wild-life signs included this fox-hole – literally! A family of foxes live here and raise their young.

Once at the beach – we noticed some ugly human impact – empty plastic bottles and other trash…

Tammy taught us how to do water testing.

And we did some soil testing as well.

Then we went and looked for fish at the shore.

We took a net to haul in what we could find.

Some of us helped clean up a bit.

And then it was already time to return back to school…

Our first Results:

LOCATIONS VARIABLES	SITE 1 Ft. McHenry Beach (Date: 10/5)		SITE 2 Sligo Creek (Date: 10/5,6)		SITE 3 Sligo Pond (Date: 10/5,6
*ABIOTIC*
pH	5.0		8.0		7.0
Temperature(Celsius)	23.1		21.1		24.0
Tidal or Non-tidal?	YES		NO		N0
Salinity, ppt	11.8		0		0
Dissolved Oxygen (DO), ppm	11		NOT AVAILABLE		NOT AVAILABLE
Nitrates, ppm	0		0		5
Phosphates, ppm	0		2		2
Turbidity, visual	clear to bottom (6”)		clear to bottom (4”)		bottom not visible (6”)
*BIOTIC*
*Biodiversity*	List Species	Count Individuals	List Species	Count Individuals	List Species	Count Individuals
Producers
Consumers
Decomposers