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Chapter 4: Living Breakwaters Energy Webs
This curriculum resource is part of a series of lessons relating to the Living Breakwaters Project and funded by the U.S. Department of Housing and Urban Development and implemented by the Governor’s Office of Storm Recovery.
Lesson Plans
Who are the muckety-mucks in Raritan Bay?
What's so bad about hitting rock bottom?
Which critters do you hope to find at the Living Breakwaters?
Which critters can you find at the Living Breakwaters?
KEY Resources for teachers
Introduction
It is challenging to teach matter cycles within the Earth system versus energy flux through the Earth system, and in ecology, we often try to teach both ideas at the same time! So for a deeper dive, here’s an essay on content pedagogy, a slide show consisting of flow-chart representations with explanations in the speaker notes, and a student-friendly narrative. None of that is specific to the Billion Oyster Project (BOP) or the Living Breakwaters. It’s just foundation, in case you happen to be fascinated by such things.
In these lessons, we approach the challenge by focusing narrowly on energy flux. (For material on one matter cycle, you can refer to BOP’s Nitrogen Cycle Investigation, which is written for classes that are keeping an oyster tank.) Here we avoid talk of cycles and instead focus on the one-way paths that energy can take: in this case, starting from the Sun, through ecosystems on Earth, and ultimately into outer space.
Every model has limitations, and probably the greatest limitation of our string model is its inability to denote quantities (population size, rate of energy flux, biomass, etc.) It treats all feeding relationships as equal. So we encourage your students to improve on our model—at a minimum, as described in the first lesson in this series, to show that only a very small proportion of the energy consumed by one trophic level gets transferred to the one above it. We would love to hear about your students’ ecosystem-modeling ventures, and we hope they will present their work at our Annual BOP Research Symposium each year in June!
As your students build the energy webs in these lessons, they will see and feel that some very important critters in New York Harbor ecosystems—like amphipods, isopods, some of the fish, and blue crabs—are detritivores and/or scavengers. If you take detritus out of the energy web, most of those critters can find other things to eat, but we can’t tell from these webs whether those detritivores and scavengers can find enough other things to eat. So for a more dramatic demonstration, remove the detritivores and scavengers from these webs. Not much will be left.
As students model the energy webs associated with different Living Breakwaters habitats, they first feel (through the tension in a piece of string) and then diagram the ways that each trophic level depends on the one before it for energy. Because these are estuarine ecosystems of Raritan Bay, they feel and diagram energy webs in which detritus plays a key role.
Often, school-level energy webs skip over detritus—which is essentially animal waste, dead algae and plants, and other dead stuff that’s pretty small, all eaten by something with a mouth—and portray a world where all plants are eaten when they are alive, or else decomposed after death by bacteria and fungi.
One thing our model does rather well is it allows the students to alter the assemblage of critters in the model, and see what happens. In these lessons, we direct them toward assemblages associated with particular bottom habitats: soft bottom (Who are the muckety-mucks of Raritan Bay?) and hard bottom (What’s so bad about hitting rock bottom?).
Of course, your students can use our tools to explore other possibilities as well. For instance, they could compare invertebrate-only energy webs with vertebrate-only (good luck!) energy webs. Or they could respond to a challenge like ensuring your web supports XYZ apex predators—for instance, humans, or harbor seals, or humpback whales. They could then explore questions like, which populations would threaten my seals by suddenly dropping? And which populations would threaten my seals by suddenly rising? Or they could explore the shifts in these energy webs from one season to the next, or what changes in the energy web if the dissolved oxygen falls below 8 or 5 or 3 parts per million (PPM). The possibilities are endless!
Your students are not limited to the critter cards we have provided. We would love to see additions to the sets, created by your students. As long as it can be found in New York Harbor, it’s a good idea to include it!
We hope that students’ approaches to the central question in this series can shift as they work with the material. We figure the initial answers will be superlatives—the biggest, fastest, meanest, or cutest. As they experience the ways their critters depend on others for energy, and the ways that changing the bottom habitat changes the whole scheme of feeding relationships, we wonder if they might eventually hope to see a critter that needs the Living Breakwaters, or a critter that supports a bunch of the superlative critters.