How Does an Oyster Filter Water?

July 18th, 2011 by Sarah and Krissy

An adult oyster can filter up to 5 liters or 1.3 gallons on water an hour. That’s equal to 60 two-liter soda bottles a day, for just one oyster!  Historically, oysters could filter the Chesapeake Bay’s entire water volume in less than a week.  Today, with 1% of the oyster population left in the Chesapeake Bay, it would take oysters nearly a year.

So how do oysters do it?

Oysters are filter feeders, meaning they eat by pumping large volumes of water through their body.  Water is pumped over the oyster’s gills through the beating of cilia.  Plankton, algae and other particles become trapped in the mucus of the gills.  From there these particles are transported to the oyster esophagus and stomach to be eaten and digested.

Once the oyster removes all nutrients, indigestible material is expelled as “pseudofeces” through the anus.  The pseudofeces are expelled from the oyster’s shell via a rapid closing of valves. The expelled particles swirl through the water and resemble a smoke ring.  These smoke rings are an indication that oysters are filtering the water and doing what they are meant to do.

How Can I Teach About Oysters?

Now that you know a little bit about oysters and how they filter water, share the knowledge with your students! Here are some resources and lesson plans to help you do so:

  • Particulate Matters: Filtering Mechanism Laboratory – This dissection exercise from the Maryland Sea Grant utilizes dye to allow students to see how an oyster is able to filter materials from the environment and selectively process them as food or pseudofeces.
  • Hunting for Hemocytes: Forms Function, and Microscope Techniques – This lesson from the Maryland Sea Grant can be paired with the Particulate Matters lesson to expand on student microscope techniques and learn more about oysters.
  • Amazing Oyster – Younger students can learn about oysters through this lesson that helps them build a 3-D oyster pop-out reef!
  • Oystering on the Chesapeake Explorations 1-5 and Explorations 6-10 – Oystering on the Chesapeake, from the Chesapeake Bay Maritime Museum, offers teachers’ multi-disciplinary lesson plans to introduce students in grades 4 through 6 to the economic, environmental, and cultural significance of the oystering industry. Whatever lessons within the curriculum unit you choose, your students are sure to enjoy this exploration about the region’s oyster industry and the challenges facing the industry today.
  • Oysters and a Clear Bay – In this lesson, students will learn about the oyster population decline and regulations, and will try to “out-filter” an oyster in a lab activity.
  • Time-lapse: Oysters Filtering Water – This 44 second time-lapse video shows oysters filtering a tank of water.

Please refer to Bay Backpack’s searchable teacher resources section for more oyster-related lesson plans

Filed under: Teaching Resources
Tags: , , ,
Sarah Brzezinski is the Chesapeake Bay Program's Fostering Stewardship and Education Workgroup Team Staffer. Krissy Hopkins is a former Chesapeake Bay Program Staffer and is currently pursuing her PhD in geology at the University of Pittsburgh.

Amazing Oysters Pop-Up Reef Lesson

July 23rd, 2010 by Krissy

Using their artistic and creative skills your students can make a 3-D oyster reef just like this one.

Amazing Oysters will show elementary students how to build a 3-D pop-up oyster reef.

Oysters are truly amazing creatures.  One mature oyster can filter up to 60 gallons of water a day and oyster reefs provide vital habitat for hundreds of bay critters.

For the same amount of space, oyster reefs can have 50 times the surface area of a flat bottom. These reefs build up, just like coral reefs, to provide nooks and crannies for worms, snails, sea squirts, sponges, small crabs, fish and even baby oysters to live in.

So the oyster reef ecosystem makes the perfect local subject to teach your students about topics like biodiversity, food webs, adaptations and predator-prey relationships.

A great starting point to study oyster reefs is to use the Amazing Oysters educational activity.  In this lesson, your students will construct their very own miniature ecosystem reef.

They will learn about the critters that make the reef their home and why reefs are such a vital habitat.  Students will also discover the threats to oyster reefs including disease (MSX and Dermo), pollution and over harvesting (waterman used to call oysters Chesapeake Gold).

To complete this activity you will need the following materials:
- Copies of the reef diagram
- Construction paper
- Scissors
- Pencils or pens
- Glue
- Crayons, markers or colored pencils
- Rulers

Get started teaching about the Amazing Oyster by downloading a copy of Amazing Oysters (pdf) or for hard copy call (804) 698-4320 or e-mail Virginia.Witmer@deq.virginia.gov.

Once you complete this activity with your class let us know how it went or how you would improve the lesson by leaving a comment below.

Additional Resources
Oyster Teaching Resources – Bay Backpack
Oyster Field Studies – Bay Backpack

Filed under: Teaching Resources
Tags: , ,
Krissy Hopkins is a former Chesapeake Bay Program Staffer and is currently pursuing her PhD in geology at the University of Pittsburgh.

Mentoring Transforms Students into Scientists

April 23rd, 2010 by LeeAnn
To record monthly mortality and growth, students retrieve one of their experimental oyster cages at the Cooperative Oxford Lab pier.

To record monthly mortality and growth, students retrieve one of their experimental oyster cages at the Cooperative Oxford Lab pier.

The Partnership of Scientists and Students for the Environment (POSSE) is a program which matches scientist mentors to high school students, and promotes and supports community partnerships. Mentorships range from interviews, emails, and phone calls to active engagement in research, whereby students work side by side with their respective scientist mentors.

Working alongside their mentor, students are learning how the experts assess the bats and how to record data accurately. They are also learning that bats contribute crucially to the food web, including their beneficial consumption of mosquitoes, and thus stability and health of an ecosystem.

Working alongside their mentor, students are learning how the experts assess the bats and how to record data accurately. They are also learning that bats contribute crucially to the food web, including their beneficial consumption of mosquitoes, and thus stability and health of an ecosystem.

Initiated in Fall 2008, POSSE began with 31 students and 9 scientist mentors. It has grown to include 62 students and 35 scientists on the Eastern Shore of Maryland. Projects include research on oyster growth and mortality, where students and a mentor scientist with the Department of Natural Resources, collected data their senior year in high school up through their freshman year in college. Their work is expected to be published in a professional journal.

Stranded…
Mentoring another student project with a hands-on approach, a DNR veterinarian and marine mammal stranding team biologist expose students to issues facing seals, sea turtles and cetaceans (whales and dolphins), and the role scientists play in strandings. A recent student team researched the effects of sound and blast trauma on the hearing of cetaceans, while another team is interested in the overall causes of strandings. Mentees have participated in the stranding volunteer training, observed necropsies of affected animals, and assisted in data collection.

Gone Batty…
DNR mentors are also assisting students with investigation of White-nose Syndrome in bats, a condition associated with the deaths of over 100,000 hibernating bats in the NE United States. Students participate in the data collection, learn proper protocol during necropsy, and use USGS distribution maps to follow the spread of this disease.

Other projects include an oyster documentary, a study of mycobacteriosis, an amphibian and reptile study, harmful algal blooms, aquaculture techniques, and horseshoe crab biomedical uses.

This year’s POSSE students will present the annual Environmental Issues: A Science Symposium at Horn Point Laboratory on Thursday May 20, 2010. The event is free and open to the public. For details, contact LeeAnn Hutchison at lhutchison@msde.state.md.us.

Filed under: Field Studies,Training
Tags: , ,
LeeAnn Hutchison is an Environmental Education Specialist at the Maryland State Department of Education.

School Spotlight: The World is Our Oyster

March 29th, 2010 by Vicki
Fourth and fifth graders wade into the river to get ready for their oyster cage delivery.

Fourth and fifth graders wade into the river to get ready for their oyster cage delivery.

There’s no where I’d rather be than where I am—teaching third grade at Eagle Cove School (formerly Gibson Island Country School) in Pasadena, Maryland. Not only do I have an fabulous view of the Magothy River out of my classroom window (where on clear days I can even see the Chesapeake Bay Bridge), but I know that I’m in an amazing school dedicated to the environment. As a Maryland Green School since 2006, Eagle Cove School provides so many opportunities to our preK to 5th grade students.

Pre-K students unload their oyster cages from Magothy River Association's boat.

Pre-K students unload their oyster cages from Magothy River Association's boat.

At Eagle Cove School, we recycle everything Anne Arundel County does, with bins in every class room right next to near-empty waste baskets. As a school community we also recycle batteries, cell phones, printer cartridges, and burnt-out compact-fluorescent light bulbs for our parent body.  On campus have rain barrels painted in art class as well as bird houses and fish observation tanks built in science class.  Students have hiked our nature trail, seined the river, and built rain gardens and a geodesic dome greenhouse.  We raise oysters, eels, terrapins, and bay grasses to be returned to the Chesapeake Bay.  We watch butterfly eggs turn to caterpillars, then chrysalises, then to monarchs in our butterfly garden.  It is hard to be in this setting, building these habits and having these experiences, and not be active toward our environment.

During Eagle Cove's Third Grade field trip students released their oysters back into the river.

During Eagle Cove's Third Grade field trip students released their oysters back into the river.

The world truly is our oyster in 3rd grade. After a-half-dozen years of being affiliated with the Chesapeake Bay Foundation’s Oyster Gardening Program, it has been our third grade tradition to help raise oysters and return these natural filters to the Bay. All year long, students raise oyster spat, weekly checking the water’s temperature, salinity, and clarity while also measuring, monitoring, and charting the spat’s growth. Donning life jackets, students trek down to the dock each week to tend to this routine chore—but hardly a chore it is seen to be!

The third graders return from a hard day's work cleaning up the bay one little oyster at a time.

The third graders return from a hard day's work cleaning up the bay one little oyster at a time.

To culminate this year long activity of nurturing our oyster babies, we go on a full-day field trip in the spring which begins at our school dock. The Chesapeake Bay Foundation’s captain and first mate onboard-educators pick us up by boat and take us out on the Magothy River. Once on the water, our guides have us navigating maps, searching for signs of diversified wildlife, and finding all the right oyster-loving conditions—all the while sea spray hits us as we go.

The pinnacle of the trip is using our water condition data that we collect as we go to drop anchor and release our ready oysters out to sea. It’s an exuberant “oysters be free” moment of thrusting the oysters overboard by the handful. In my 18 years of teaching, it is by far the best, most exhilarating field trip I have ever attended!

For this year’s third graders it will be especially meaningful in that the first Friday of our school year, the entire school body united with the Magothy River Association to take part in the “Marylanders Grow Oysters” Program through the Department of Natural Resources and the Oyster Recovery Partnership. Our school was one of the pickup points for Marylanders to get their own oyster spat. Of course, to be a pick up point, we had to first get the 320 cages off trucks, down to the dock, and placed on pallets in the river for 2 weeks until the pickup date. Amazing how quickly that can take place when you have a whole community of school children (even the youngest 3 and 4 year olds) ready to step right up and do their part!

As we soak up nature from the campus that surrounds us at Eagle Cove, we learn both as students and as teachers. The world is our oyster, and we take advantage of it every day! No doubt, the planet will benefit from the budding citizens that make up our Eagle Cove’s student body.

Additional Resources:

Filed under: School Spotlight
Tags: , ,
Vicki Dabrowka is a Third Grade Teacher and Co-“Green Team” Leader at Eagle Cove School in Pasadena, Maryland. She is also the author of “The Green Team Gazette,” a blog on green living & green educating.

Become an Oyster Gardener

January 10th, 2010 by Krissy
After tending their oyster garden all school year, these Virginia students released their oysters into the river.

After tending their oyster garden all school year, these Virginia students released their oysters into the river.

Tending an oyster garden is a great way to get your students actively involved in efforts to restore the Chesapeake Bay. The Eastern Oyster is one of the most important species in the Chesapeake Bay because of its ability to filter water. One adult oyster can filter up to 50 gallons of water a day. But because of over harvesting and disease the oyster population is at 1% of its historic level. By becoming an oyster gardener your class can help boost the oyster population and make the waters of the Chesapeake a little cleaner.

Here’s how you can participate. Your class can construct oyster cages out of wire mesh or PVC piping. The cages are then filled with baby oysters called ‘spat’ that you will care for over the next year. Oyster cages can be hung from a pier or piling close to your school. During the year your students will have to care for your oyster cages, cleaning the muck off of them weekly. Once your oysters mature and grow they will be collected and planted in a sanctuary reef.

You can integrate math, science and writing skills into an oyster gardening project by measuring the growth of your oysters over the school year and having each student keep an observation journal recording any other critters you find living in the oyster cages. You can also teach your students about the historic oyster catch through activities such as Oysters and a Clear Bay.

To find an oyster gardening program in your area visit Marylanders Grow Oysters, the Chesapeake Bay Foundation’s Oyster Program or Virginia Oyster Gardening Program.

Additional Resources:
Oyster Gardening Guide (pdf.)

Filed under: Field Studies,Teaching Resources
Tags: , ,
Krissy Hopkins is a former Chesapeake Bay Program Staffer and is currently pursuing her PhD in geology at the University of Pittsburgh.