Pictured above: Pictured above: Students identify green crabs at Broad Cove, Cumberland
At the beginning of the year, the 7-8 began a science unit on Ecosystem Dynamics, which focused on European Green crabs, a species of crab invading the Maine coast. They started by learning about the intertidal zone and played a game displaying how green crabs affected the species richness and diversity of life living there. They learned how to ID crabs and analyze data in preparation to collect their own for the GMRI (Gulf of Maine Research Institute) Citizen Science Project which they participated in along with other Maine schools.
The research questions for the investigation were:
How do the populations of Native, Green, and Asian Shore crabs compare along the Maine Coast?
Are crab populations changing over time in response to warming temperatures?
Where do we predict Native, Green, and Asian Shore crabs will be in the future?
On their first field trip, they went to Broad Cove looking for green crabs. They found some in eelgrass, an area where they learned green crabs are commonly found in class. Green crabs often damage eelgrass beds by burrowing into the soil or clipping the blades to find bivalves to eat. Burrowing into the eelgrass is one way that Green crabs have adapted to survive cold winters in Maine.
On their second outing, they went to Mackworth Island and gathered in small groups to set up 1x1 meter quadrats along the shoreline transect. They spent an hour looking for crabs of any species (the four main types are the invasive Green and Asian Shore, and the Native Jonah, and Rock crabs) in their respective quadrats, digging in the sand, and looking under rocks and seaweed.
Pictured above: Students participating in the GMRI protocol for Intertidal Crab Investigation
When they got back to school, they entered their data including species found, size, sex, shell type, and number of claws in the GMRI database https://investigate.gmri.org/project/intertidal_crabs/ and made a scatter plot from the data that they gathered. They found only Green crabs.
Next, they went to Wells Reserve. There they got to look at water samples with different types of plankton under a microscope to see what was in the water column. They talked with scientists doing real studies on green crabs with hopes of coming up with solutions to the invasive species problem. They spent time looking at graphs and taking blood samples from live Green crabs to test the levels of protein in them (using a refractometer) to try to predict when a crab was ready to molt.
Pictured above: Students view plankton via dissecting and compound microscopes and look through refractometers to measure proteins in crab blood.
On their last trip, they went to Kettle Cove in Cape Elizabeth. There, they followed the same protocol as they had at Mackworth, but found very different results. They still found many Green crabs, but they found even more Asian Shore crabs, with numbers up to 50 in a single one-meter square as seen in the graph below.
Pictured above: Students setting up a quadrat at Kettle Cove (left) and identifying an Asian Shore Crab (right).
Finally, students wrote claims based on the Research Questions, focusing on engaging in an argument from evidence (using GMRI data, CODAP graphs made by students, Wells Reserve data, and class data). They learned how to ensure validity in their data, how to consider and rule out counterclaims, and how to pose questions to investigate their claims further. The final step was picking out a way to share their findings with the community, which included sharing with the Gulf of Maine Research Institute live Zoom session with other students and scientists from across the state, with Grandfriends and parents in the CER gallery, and the wider school community via the e-bulletin and here in the FSP Quarterly newsletter! Enjoy checking out some of the student reports below!
Green crabs will support Maine's newest fishery- Michaela
Asian Shore crabs will out compete European Green crabs- Xander
Atlantic Blue crabs will take over the population of Green crabs- Max
Green crabs will be Maine's Newest Fishery- Eric
Green crabs will become Maine's newest fishery- Theo