The Freshwater Mussels Hatchery and Aquatic Field Station Program at the Fairmount Water Works Interpretive Center in Philadelphia is an excellent example of putting a theory into practice.  Through science, art, and new technologies, the  program demonstrates the extent to which mussels could contribute to the restoration of our degraded freshwater system. This experiment will always be in flux—much like the natural environment that inspires us.

Mussels are amazingly efficient and effective water filters–that is a “service” they provide naturally in an ecosystem. Propagating them in this small-scale hatchery and re-introducing them where they can survive and  thrive (they became endangered historically) will demonstrate the ecological benefits of freshwater mussel restoration in improving the health of our waterways.

Freshwater mussels are the subject of an extensive research project on aquatic restoration in the Delaware Watershed. This learning experience will give students growing up in our watershed the chance to come to know about this important work .

This brief document will provide you with more in-depth information about Philadelphia’s program.

One of the major reasons for the historic decline of freshwater mussels is because of  legacy pollution from past industrial pollution.  Before such legislation like the Clean Water Act, Industry generated pollutants like heavy metals from manufacturing ended up in our waterways. Unfortunately, even though the dumping of waste directly into our waterways is no longer allowed, a legacy of pollution from past manufacturing may still be present in the river’s sediment . Another reason for near extinction was the over-harvesting of mussels for products like buttons made from their shells.

Throughout Understanding the Urban Watershed students have been exploring the issues, challenges, and key ideas related to clean water in Philadelphia. At the center of it all are our rivers (the source of our drinking water supply) .

Setting up the big picture:

Click on the landing page from mightymussel.com website.

Ask students to point out a few things they notice and wonder .

They will return to this site later in the lesson to explore on their own.

Now  demonstrate how to discover more information from this landing page by hovering over a few of the + signs with your mouse. Click through one or two topics to show them how they can learn more from this depiction of the ecosystem.

Slide 3: Next click on Two Tank Demonstration and watch the very short video showing how mussels are able to filter water quickly and efficiently. The video is also embedded in the slide deck.

• How does this contribute to the health of the river?
• How does this support the other organisms living in the river?

We can refer to this as a SERVICE that the mussels provide to the ecosystem. This is a service they provide for free!

“Zoom” in on the details of the freshwater mussel and all that it can provide in the larger ecosystem.

Slide 5: Mussel Anatomy

Slide 6: Life Cycle

To review this slide with the students, start at the BOTTOM with Adult Mussel.

Adult Mussel to Glochidia – Fertilization

• Sperm release: Male mussels release sperm directly into the open water.
• Siphon intake: Females downstream draw in the sperm through their incurrent siphons.
• Brooding: Eggs are fertilized internally and stored in specialized gill chambers called marsupia to develop into microscopic larvae called glochidia. [1, 2]

Fish Host – luring and attachment

• Luring the fish: Females use a modified part of their body or mantle tissue as a decoy lure that mimics small fish or insects.
• Infecting the host: When a curious fish approaches or bites the lure, the female releases glochidia directly into the water or onto the fish.
• The ride: The tiny larvae latch onto the gills or fins of the specific host fish species, forming a small protective cyst.

Metamorphosis

• Riding along: The larvae stay attached to the fish for two weeks to several months, safely traveling upstream or downstream and receiving nutrients.
• Transformation: While on the fish, the glochidia transform and grow into tiny juvenile mussels.

Juvenile and Adult Stage

• Dropping off: The young juvenile mussels detach from the fish host and sink to the bottom of the stream, river, or lake.
• Burrowing and growing: Juveniles burrow into the sediment (substrate), where they begin filter-feeding on algae and bacteria, eventually growing into mature adult mussels.

Slide 7: Review and reinforce the ECO SYSTEM SERVICE that the mussels provide to the ecosystem.

Natural water filters that clean vast volumes of water contributing to the health of the ecosystem as a whole.

What do they need to thrive?  Host fish to protect them and transport them.

 

Slide 8: Why is all this happening  with the help of human intervention?

The answer is: they rely on the fish for protection from predators, nutrition, and transportation upstream. If they did not attach themselves they would simply sink into the mud at the bottom of the river, or wash downstream into a habitat that was not supportive of their growth and development.

Ask students why they think humans had to intervene to help protect and restore freshwater mussel habitats?

The answer is:  Past destruction and current threat to the natural habitat in the river through pollution, dredging, and climate change. In addition, mussel babies are vulnerable to polluted sediment and poor water quality. A hatchery and select grow-out ponds  protect the babies and growing mussels  until they are larger and able to be re-introduced into the rivers and thrive in the natural riverbed.

Slide 9: Show two very brief videos from the Mussel Hatchery at the Fairmount Waterworks.

Hatchery Video 1 matchmaking  https://vimeo.com/229717507?fl=pl&fe=sh

Hatchery Video 2 Growing Mussels  https://vimeo.com/229717618?fl=pl&fe=sh

Slide 10: An additional video with a closer look at the full process TBD

Slide 11: We have been exploring the services that freshwater mussels provide to a healthy ecosystem. We are now going to look at the ecosystem in the Schuylkill River.

This activity will be an exploration of the importance of diversity in local water systems and the services that each organism contributes.

Slide 11: Using the  Mighty Mussel website  explored earlier as a class, students can explore the homepage interactive graphic individually or in pairs to discover and then discuss the benefits of diversity.

The key point here is that all of the organisms living in a healthy ecosystem provide services to other organisms – making it sustainable. These services also provide benefits to us. In the case of the mussels, it is filtering water and providing habitat for other organisms . They also serve as key bio-indicators of the health of our waterway.

Have students select an organism (plant or animal) of interest to them and identify the services their organism provides to the ecosystem. What other organisms does it depend on? And what depends on it? Have them consider what would happen if an organism was removed from the ecosystem.

If students are interested in exploring more examples of animals as engineers, use the following slide/website to facilitate their exploration.

Slide 12: The website offers additional videos depicting different animals and how they naturally engineer a solution to a problem. Divide up your students into 8 groups and assign each group one of the videos to watch and take notes (they are short and may need to watch them multiple times). (Be prepared for some oos and ahs !)

Shape of Life: Animals as Engineers

As students share their findings, have them suggest examples of how humans have learned from their engineer and how the skills are seen in our everyday lives.