EO - Aquatic Biomes Lesson

Aquatic Biomes

Introduction

If someone was to ask you where you want to go on vacation, what would your answer be? Chances are you thought of a place such as Paris, New York, the Rainforest, the Swiss Alps, etc. What do each of these have in common?

They are terrestrial places – land locations. Very rarely does someone say I want to visit the Dead Sea, Gulf of Mexico, Okefenokee Swamp, or the Amazon River. Why is it we automatically think of ‘land locations’ and not aquatic?

About 71% of the Earth's surface is covered with water and 96.5% of that is in the ocean.

So let’s give a little more thought to the aquatic biome.

Fresh vs Salt

Did you know that 71% of the Earth’s surface is covered by water making the Aquatic Biome the largest one on Earth? Like all other biomes, the aquatic biome can be subdivided into Freshwater and Saltwater regions.

Freshwater regions include wetlands, lakes and ponds, rivers and streams.

Saltwater regions include Oceans, Coral Reefs, and Estuaries.

Let's Go On a Road Trip!

FRESHWATER BIOMES: Freshwater biomes can be defined as having a low salt concentration – less that 1%. Less than 2.5% of the world is covered in freshwater. Because there is low salt concentration, animals and plants are adapted to life with little salt in the environment. SALTWATER ECOSYSTEMS: Saltwater ecosystems are classified as oceans, coral reefs, or estuaries. In these ecosystems algae supply much of the world its oxygen supply and take in vast amounts of atmospheric carbon dioxide. The evaporation of seawater provides rainwater for terrestrial biomes.

Take a look at the state of Georgia below. Click on each area to learn more about the specific biome.

Let's Recap!

Freshwater Biomes

• Freshwater biomes can be defined as having a low salt concentration – less that 1%.
• Examples:
  • Lakes and Ponds: Lake Lanier
  • Rivers and Streams: Example Chattahoochee River
  • Wetlands: Okefenokee Swamp

Saltwater Ecosystems

• The evaporation of seawater provides rainwater for terrestrial biomes.
• Examples:
  • Oceans Example: Atlantic Ocean Tybee Island
  • Coral Reefs: Grays Reef
  • Estuaries: Sapelo Island

Some freshwater and saltwater examples need a bit more explanation. We can break these down into further categories.

Ponds and Lakes Primary Zones

Ponds and lakes can be divided into zones based on depth and distance from the shoreline.

Littoral Zone: Is uppermost near the shore of the lake or pond. It is the warmest and most shallow. This zone can sustain a diverse community of algae, snails, insects, fish, crustaceans, and amphibians.

Photic Zone or Open Water: This zone is also called the limnetic zone, and the littoral zone surrounds it. This area is well lighted and includes phytoplankton and zooplankton and freshwater fish. Plankton is a small protist that is crucial in the food chain.

The Aphotic Zone or Deep-Water Zone: This zone is also called the profundal zone. When the plankton from the Limnetic zone dies, it falls to the lower part of the lake called the profundal zone. This area is much colder and darker because not much light reaches it. Organisms that live here are heterotrophs eating the dead organisms that fall to the floor.

Ocean Zones

Though there is a great diversity of life in each ocean, they can each is separated into regions or zones which include intertidal, pelagic, abyssal, and benthic

• Intertidal Zone – This is where the ocean meets the land. As ocean currents come in and out, it is sometimes submerged and sometimes exposed causing the community to change regularly. The intertidal zone usually has the greatest diversity of plant and animal life out of any of the zones.
• Pelagic Zone – Water that is further away from land, and is often called the open ocean. This zone tends to be colder, but it is hard to average because there is a constant swirling of warm and cold ocean currents. Life includes phytoplankton, seaweed, fish, and large mammals such as whales and dolphins.
• Benthic Zone – This is the zone right below the pelagic zone – but is not the deepest zone. Temperatures are colder than the pelagic zone and because there is not much light life is mainly seaweed, bacteria, fungi, sponges, sea anemones, worms, sea stars, and fishes.
• Abyssal Zone – The coldest region of an ocean with high water pressure and oxygen content. There is very little nutritional content, so life is less diverse. This zone can support bacteria, invertebrates and some fish.

Before we spend time reviewing the steps of the scientific method, take a look at the following graphic organizer to help guide you through the information.

Aquatic Biomes Challenge

Before You Go, You Need to Know

The following key points are from this explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

IMAGES CREATED BY GAVS OR OPEN SOURCE