Objectives
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List a variety of organisms which live in the marine and estuarine environment and describe how they are connected.
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Describe the concept of a “keystone species” and explain the role that such an organism plays in its environment.
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Explain the term “species at risk” and list examples of marine species at risk.
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List and describe human impacts on ocean environments.
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List and describe ways in which we all can be ocean stewards.
Materials
Background
The coastal environment can be split into three distinct marine ecosystems:
- Estuary
- Nearshore
- Open ocean
An estuary is formed where rivers and streams flow out and mix with salt water from the ocean. At high tide, when the ocean has rushed towards the shore, an estuary contains a higher amount of salt water. At low tide, when the ocean has moved out of the river mouth, the estuary may dry out and expose rocks, mud and plants to air and sunlight. The estuary is an important part of the lifecycle of the salmon. Their time in the estuary allows their body to adapt to a saltier environment. Estuaries are also known as ‘nursery areas’ because they offer young fish and invertebrates places to hide from predators.
Nearshore ecosystem of British Columbia include the intertidal zone and kelp forests. Many different species live there. These species include seaweeds, fishes, invertebrates (animals without backbones) and marine mammals (orcas, sea lions, seals and sea otters.)
The open ocean is home to large whales, adult salmon, and large-winged seabirds like albatross. Off the coast of British Columbia, the ocean is extremely deep. The darkness of deeper water provides many places for prey to hide. The deep areas off the coast also provide a lot of nutrients that flow into nearshore environments each spring after winter storms. This regeneration of nutrients is called ‘upwelling’.
Many of our activities on land, whether we live close to the ocean or far away, affect the ocean. Chemicals that are poured down drains or otherwise enter waterways eventually make their way into streams, out estuaries and into the ocean. According to the World Wildlife Fund, over 80% of marine pollution can be directly associated with land-based activities.
Federal and provincial governments have taken action to protect important coastal species. To prevent wildlife from becoming extinct, Canada’s federal government proclaimed the Species at Risk Act (SARA) in 1993. Currently few aquatic species are protected under this Act, the majority of which are freshwater fishes. A group of scientists and wildlife experts (the Committee on the Status of Endangered Wildlife in Canada) can recommend that creatures be added to the list. Once a species is listed as endangered or threatened, it becomes illegal to kill, harass, capture or harm it in any way.
Vocabulary
Echolocation: Finding out the location of an object by sending out a sound signal and listening to the echo that is returned.
Ecosystem: A natural environment that includes living and nonliving things interacting, resulting in a stable environment.
Endangered: A species of plant or animal whose existence is threatened with immediate extinction.
Extirpated: A species of plant or animal which is no longer found in a certain area.
Estuary: A body of water formed where freshwater from rivers and streams flows into the ocean and mixes with the saltwater.
Food chain: Plants and animals are linked in a food chain by what they eat and what eats them. For example, a leaf from a plant, a leaf-eating insect and an insect-eating bird form a simple food chain.
Food web: An interlocking pattern of food chains that usually includes several producers, herbivores, omnivores and carnivores.
Kelp: Any of various brown, often very large, seaweeds that grow in colder ocean regions.
Keystone species: A species that has a unique role in the structure of an ecosystem. If a keystone species’ population dwindles or disappears, there can be far-reaching consequences for that ecosystem.
Population: The number of a particular species in an area.
Stewardship: Related to the environment, the idea of responsible caretaking. Based on the principle that humans do not own natural resources, but are managers and caretakers of them.
Other Resources
Great Bear Sea | Elementary Resources | Secondary Resources
Ocean Wise | Educator Kits
Ocean Wise | Great Canadian Shoreline Clean-up
Ocean Wise | Adopt a Whale
Shaw Centre for the Salish Sea | Learn
Government of Canada | Fisheries and Oceans | Salmon