The Freshwater Mussels research project in Philadelphia is an excellent example of how scientists work with nature in urban environments to improve water quality and restore our health and the health of our waterways.

Mussels are amazingly efficient and effective water filters–that is their role/niche in the ecosystem. Re-introducing them and creating favorable conditions for them to thrive (after creating unfavorable conditions for them historically) restores dynamic balance and diversity to the waterways in our ecosystem

Fresh Water Mussels are the subject of an extensive research project on aquatic restoration in the Delaware Watershed. Everybody living, working and growing up in our watershed should know about this important work.

This brief document will provide you with more in-depth information about mussels and the mussels project in Philadelphia.

One of the major reasons for the historic decline of freshwater mussels is due to legacy pollution from industry in the last 150 years.

Industry generated pollutants like heavy metals from manufacturing that ended up in our waterways. The “legacy of pollution” from manufacturing is still present in the sediment in our waterways and does not disappear (because there is no such place as away!)
Another reason is over harvesting for products made from mussel shells like buttons (anthropocentric).

All human activity draws on natural resources and has both short and long-term consequences, positive as well as negative, for the health of people and the natural environment.

Every species has a specific role to play in nature. The freshwater mussel is a natural water filtration system.

Throughout the learning experiences 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 pictures from mightymussel.com website are shown on SLIDE X

Looking at the pictures, have students point out the differences in the illustrations.

 

Open the website mightymussel.com   and show the landing page to the students.  They will return to this site later in the lesson to explore on their own.

Click on the Large + hovering over the river with the title   Flowing River  to open up the info box for that element.

Click on the title:  The Good & Bad Habitat.

Review the text listed below the illustrations.

 

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!

Slide 5: Mussel Anatomy

Slide 6: Life Cycle

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

1. 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]

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.
• Parasitic ride: The tiny larvae latch onto the gills or fins of the specific host fish species, forming a small protective cyst.

3. 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.

4. 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 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 services do they need to thrive?  Host fish to protect them and transport them upstream.

 

Slide 8: How does this all happen 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: Destruction of the natural habitat in the river through pollution, dredging, and climate change. In addition, mussel babies are vulnerable to sediment and poor water quality. A hatchery is able to protect the babies until they are larger and able to 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

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.

Using Mighty Mussel website students explore the homepage interactive graphic 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 giving us a real-time indication 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.