Lesson 44 Aquatic Ecosystems: Oceans part 2

In our last lesson we learned that oceans are large bodies of saltwater divided by continents.

We learned that oceans can have different types of ecosystems depending on the conditions (sunlight, temperature, depth or salinity) of that part of the ocean.

In our last lesson we learned about the aquatic ecosystem called the ocean. We learned that the ocean had lots of layers with each layer containing a different set of species.

We learned that most organisms live where the ocean is shallow (from the shoreline to the continental shelf) because sunlight can reach deep and the water is warm making food abundant.

We learned that some examples of organisms that live in the shallow ocean are drifters (jellyfish or seaweed), swimmers (fish), crawlers (crabs), and those anchored to the ocean floor (corals) or down to the deep ocean bottom.

Today we will learn about organisms who live in the open ocean, near the surface in the pelagic zone.

Sunlit or euphotic zone is the top layer of the ocean and it gets the most sunlight.

The sunlight provides energy to the ocean organisms through photosynthesis. It feeds plants, as well as very small organisms called plankton.

Plankton are very important in the ocean because they provide the food basis for much of the rest of ocean life. As a result, around 90% of ocean life lives in the sunlit zone.

Plankton floats in the upper regions of the water. There are different types of plankton such as phytoplankton and zooplankton.

Let’s watch a video about plankton. LuXMz3j9E8k

Phytoplankton (made from plants) and zooplankton (tiny invertebrate animals) are the basis of all life in the ocean.

Fish larvae are immature free-living forms of many animals that develop into different adult forms through metamorphosis. They feed on Zooplankton.

Small fish feed on fish larvae and plankton. Herrings and Sardines are examples of small fish that are integral in the pelagic zone food chain.

Large open-ocean fish such as this Tuna depend on smaller fish and invertebrates for food. They also prey on squids, and crustaceans. Depending on the species, tuna are the second fastest species in the ocean, therefore a feared predator.

Sharks earn their spot at the top of the open ocean food chain. Sharks eat dolphins, sea lions, sting rays, large fish, or even other sharks and usually are successful because of their flesh- ripping teeth, strong jaws and impeccable sensory skills.

Bottom-feeding and scavenger sharks eat mollusks, squid, clams, and other small animals. They are efficient eaters, generally preying on weak, ill, old, or slower fish, which helps keep other animals healthy.

Without sharks, numerous fish species would be disproportionate and harmful to the ecosystem. We would also lose some commercial fish and shellfish, some of which help maintain our coral reefs.

XzGuQ2MqE Let’s watch a video about ocean ecosystems.

Some organisms swim to the surface to find food or for air (whales, turtles, sharks) while others live closer to the bottom (certain fish, octopus, tubeworms).

CYrlvuhdc Let’s watch a video about open oceans.

Let’s review what we have learned from this lesson. Answer the attached questions on the worksheet entitled L#44 Aquatic ecosystems: oceans part 2.

In our next lesson we will learn how to classify organisms.

Good Job Today! And remember to….

See you next time!