Unit E Lesson E9
Completion requirements
Lesson E9: Living in Water
Video Lesson
Earth is home to diverse aquatic organisms. Watch this video to learn more about the special adaptations of some aquatic organisms.
Lesson E9: Living in Water
Figure E.3.9.1 – Freshwater eels are born in the ocean, but live most of their lives in rivers.
Figure E.3.9.2 – Salmon live in the ocean, but spawn in freshwater rivers.
Figure E.3.9.3 – Sturgeon fish are adapted to live in both fresh and saltwater environments.
Reading
and Materials for This Lesson
Science in Action 8
Reading: Pages 373–380
Materials:
No additional materials needed for this lesson.
Euryhaline Organisms
Most aquatic species are very sensitive to changes in water salinity. Most aquatic organisms are adapted to live in either fresh water or salt water, but not both.
A small number of euryhaline organisms are able to live in both saltwater and freshwater environments. Euryhaline bodies have special receptors that sense the environment’s salinity. The euryhaline organism’s body cells can then adjust their concentration according to the environment.
Salmon and sturgeon fish are born in freshwater rivers, but spend most of their lives in the ocean. As adults, both of these species return to freshwater rivers to spawn, or reproduce. Salmon spawn once, and then die. Sturgeon can alternate between fresh and salt water, to spawn many times.
Freshwater eels have an opposite life cycle to salmon. Freshwater eels are are born in the ocean, spend most of their lives in fresh water, and then migrate back to the ocean to spawn.
Most aquatic species are very sensitive to changes in water salinity. Most aquatic organisms are adapted to live in either fresh water or salt water, but not both.
A small number of euryhaline organisms are able to live in both saltwater and freshwater environments. Euryhaline bodies have special receptors that sense the environment’s salinity. The euryhaline organism’s body cells can then adjust their concentration according to the environment.
Salmon and sturgeon fish are born in freshwater rivers, but spend most of their lives in the ocean. As adults, both of these species return to freshwater rivers to spawn, or reproduce. Salmon spawn once, and then die. Sturgeon can alternate between fresh and salt water, to spawn many times.
Freshwater eels have an opposite life cycle to salmon. Freshwater eels are are born in the ocean, spend most of their lives in fresh water, and then migrate back to the ocean to spawn.
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Eels and Salmon
Watch this video to learn more about an eel’s life cycle.
Watch this video to learn more about an eel’s life cycle.
Watch this video to observe the life cycle of the sockeye salmon in BC.
Figure E.3.9.4 – Many tropical river estuaries are home to mangrove forests.
Figure E.3.9.5 – Mangrove trees are rooted underwater.
Figure E.3.9.6 – Mangrove tree roots are exposed at low tide.
Brackish Water Trees
Estuaries are located where freshwater rivers meet saltwater oceans. Fresh and salt water mix in estuaries, creating water that is brackish, or slightly salty.
Mangrove trees are found in tropical and subtropical estuaries. Mangrove tree roots are adapted to live in brackish water. Mangrove roots have the ability to filter out salt. Small holes on mangrove roots take in oxygen from the air when the tide goes out.
Mangrove forests provide important habitat for aquatic organisms in estuaries. The tangled underwater roots of mangrove trees are home to fish, crab, and shrimp. Mangrove roots also help prevent erosion along coastlines.
Estuaries are located where freshwater rivers meet saltwater oceans. Fresh and salt water mix in estuaries, creating water that is brackish, or slightly salty.
Mangrove trees are found in tropical and subtropical estuaries. Mangrove tree roots are adapted to live in brackish water. Mangrove roots have the ability to filter out salt. Small holes on mangrove roots take in oxygen from the air when the tide goes out.
Mangrove forests provide important habitat for aquatic organisms in estuaries. The tangled underwater roots of mangrove trees are home to fish, crab, and shrimp. Mangrove roots also help prevent erosion along coastlines.
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Mangrove Forests
Watch this video to learn more about mangrove forests.
Watch this video to learn more about mangrove forests.
Figure E.3.9.7 – Plankton are floating aquatic organisms.
Figure E.3.9.8 – Plankton are an important part of aquatic food chains.
Figure E.3.9.9 – Some of the largest ocean creatures rely on eating plankton for their survival.
Floating Ocean Organisms
Plankton is a term used to describe a group of small floating aquatic organisms. Plankton float along with water currents, because they can’t actively swim against currents.
Plankton are a diverse group of organisms that include bacteria, algae, and animals. Different kinds of plankton live in fresh water and salt water. Some plankton cannot be seen without a microscope, and others are large, such as jellyfish. Phytoplankton such as algae photosynthesize to make their own food. Zooplankton such as krill eat other plankton as food. Many larger aquatic organisms rely on plankton for food.
Plankton were some of the earliest organisms to evolve in Earth’s oceans. Millions of years ago, dead and decomposing plankton settled at the bottom of oceans. Over time, layers of mud and sediments covered and compressed the decomposing plankton into sludge, turning it into fossil fuels like oil and natural gas.
Plankton is a term used to describe a group of small floating aquatic organisms. Plankton float along with water currents, because they can’t actively swim against currents.
Plankton are a diverse group of organisms that include bacteria, algae, and animals. Different kinds of plankton live in fresh water and salt water. Some plankton cannot be seen without a microscope, and others are large, such as jellyfish. Phytoplankton such as algae photosynthesize to make their own food. Zooplankton such as krill eat other plankton as food. Many larger aquatic organisms rely on plankton for food.
Plankton were some of the earliest organisms to evolve in Earth’s oceans. Millions of years ago, dead and decomposing plankton settled at the bottom of oceans. Over time, layers of mud and sediments covered and compressed the decomposing plankton into sludge, turning it into fossil fuels like oil and natural gas.
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Plankton
Watch this video to see some amazing microscopic images of plankton.
Watch this video to see some amazing microscopic images of plankton.
Figure E.3.9.10 – Giant tube worms have been found more than 1.5 km below the ocean surface.
Figure E.3.9.11 – Some deep ocean organisms produce light by bioluminescence.
Figure E.3.9.12 – Large teeth help deep sea fish hold onto their prey.
Life in the Deep Ocean
Oceans are very deep. The average distance from sea level to the ocean floor is 3.5 km. The deepest ocean spot on Earth is the Mariana Trench, which is nearly 11 km below sea level. Organisms in the deep ocean have special adaptations to survive in this cold, dark environment.
Bioluminescence is a common adaptation for deep ocean organisms. Bioluminescence is a chemical reaction that produces light inside an organism’s body. Bioluminescence can help organisms to search for food and attract prey. It can also help members of a species communicate. Jellyfish rely on bioluminescence to startle and scare off predators.
Finding prey can be difficult for organisms in the deep ocean. Some deep ocean fish have large teeth so their prey can’t escape. They also have slow metabolisms, which enables them to survive a long time without eating.
Oceans are very deep. The average distance from sea level to the ocean floor is 3.5 km. The deepest ocean spot on Earth is the Mariana Trench, which is nearly 11 km below sea level. Organisms in the deep ocean have special adaptations to survive in this cold, dark environment.
Bioluminescence is a common adaptation for deep ocean organisms. Bioluminescence is a chemical reaction that produces light inside an organism’s body. Bioluminescence can help organisms to search for food and attract prey. It can also help members of a species communicate. Jellyfish rely on bioluminescence to startle and scare off predators.
Finding prey can be difficult for organisms in the deep ocean. Some deep ocean fish have large teeth so their prey can’t escape. They also have slow metabolisms, which enables them to survive a long time without eating.
Watch More
Deep Ocean Creatures
Watch this video to learn more about some interesting organisms in the deep ocean.
Watch this video to learn more about some interesting organisms in the deep ocean.
This deep sea dive explains the adaptations of some aquatic organisms in the deep ocean.
Watch this video to learn more about the adaptation of bioluminescence.
Figure E.3.9.13 – Wetlands provide important habitat for waterfowl.
Figure E.3.9.14 – Wetlands are located in all areas of Canada.
Figure E.3.9.15 – Bulrushes are common plants in wetlands.
Wetlands
Wetlands are low-lying land areas that are filled with water. Aquatic plants grow in wetlands. In Canada, wetlands often contain bulrush plants with cattail flowers. Wetlands provide a habitat for numerous species, including fish, waterfowl birds, and insects.
Wetlands perform important jobs in addition to providing habitat. Wetlands store water runoff during flooding, preventing other land from becoming saturated. Water in wetlands percolates into the ground, replenishing groundwater supplies. Wetland plants filter pollutants out of water. Wetland plants remove carbon dioxide from the air, reducing the effects of climate change.
In the past, people have viewed wetlands as wasted and unusable land. Today, we know that wetlands are an important ecosystem for the health of many species. Scientists are working to preserve wetland habitats.
Wetlands are low-lying land areas that are filled with water. Aquatic plants grow in wetlands. In Canada, wetlands often contain bulrush plants with cattail flowers. Wetlands provide a habitat for numerous species, including fish, waterfowl birds, and insects.
Wetlands perform important jobs in addition to providing habitat. Wetlands store water runoff during flooding, preventing other land from becoming saturated. Water in wetlands percolates into the ground, replenishing groundwater supplies. Wetland plants filter pollutants out of water. Wetland plants remove carbon dioxide from the air, reducing the effects of climate change.
In the past, people have viewed wetlands as wasted and unusable land. Today, we know that wetlands are an important ecosystem for the health of many species. Scientists are working to preserve wetland habitats.
Watch More
Wetlands
Wetlands are an important freshwater system. Watch this video to learn more.
Watch this video to learn more about some of the important functions of wetlands.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit E Lesson 9 Self-Check
Instructions
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Large, flat leaves expose the water lily plant to sunlight for photosynthesis. Food made through photosynthesis in the leaves supports the rest of the plant underwater.
Wetlands serve many purposes, including:
- Removing pollutants from water
- Holding extra runoff water, which prevents widespread flooding
- Providing habitat for fish, waterfowl, and insects
- Replenishing groundwater stores
Plankton describes small floating organisms in aquatic ecosystems. Plankton are important to aquatic ecosystems because they are an essential source of food for larger aquatic organisms. Like grass growing on land, phytoplankton use the energy
of Sun and carbon dioxide to make their own food – this makes phytoplankton the beginning of the ocean food chain.
The adaptation of bioluminescence has many benefits including:
- Acting as a defence against predators, startling predators away
- Enabling organisms to see and hunt prey
- Allowing communication between members of a species
Both mangrove estuary and freshwater wetlands contain plants rooted in sediments beneath the water. These plants grow above the water’s surface. Both mangrove estuary and freshwater wetlands provide important habitat for a large number
of species.
Mangrove estuaries are located where rivers flow into the ocean, which means they have a higher salinity than freshwater wetlands.
Mangrove estuaries are located where rivers flow into the ocean, which means they have a higher salinity than freshwater wetlands.