Aquatic Ecosystems

Aquatic Ecosystems What factors affect life in aquatic ecosystems? What are the major categories of freshwater? Why are estuaries so important? How do ecologists usually classify marine ecosystems?

Organisms are affected by the water’s depth, temperature, flow, and amount of dissolved nutrients • Different zones in the water Conditions Underwater

The surface region known as the “photic zone” it is the zone that sunlight hits • Zone where photosynthesis can occur • In tropical seas it can reach depths up to 200 meters Photic Zone

Photosysthesis cannot occur here • It is a dark zone Aphotic Zone

The zone comprised of sediments and rocks on the bottom of lakes, streams, and oceans • Animals living here are called the “Benthos” • In places where the water is shallow and may be exposed to light there are algae and aquatic plants • If it is not shallow, chemosynthetic organisms are the primary producers Benthic Zone

Like terrestrial environments aquatic environments are warmer near the equator, and colder away from it • Temperature varies with depth • Currents affect temperature Temperature and Currents

Nutrients needed in waters are: Oxygen, Nitrogen, Potassium, and Phosphorus • The amount of these elements dissolved in water will affect what can live and grow there • Varies between bodies of water Nutrient Availability

Freshwater Ecosystems Rivers, Streams, Ponds, Lakes, and freshwater wetlands

Usually come from underwater springs, or from the mountains or hills, and run downward • Animals in rivers and streams may depend on plants and animals on the banks for food Rivers and Steams

Foods webs within these are usually based on Plankton, algae, and plant life • Water typically circulates between surface and benthos helping to distribute resources, heat, oxygen, and nutrients Lakes and Ponds

Water is covers the soil for at least part of the year • Water may be stagnant, or flow through the wetlands • Breeding grounds for many organisms • They help to purify the water, filtering pollutants, and prevent flooding by absorbing and releasing water Freshwater Wetlands

The saltwater version of freshwater wetlands • Formed where a river meets the sea • Water levels rise and fall with tides • Photosynthesis usually occurs here because they are typically shallow • Serve as a breeding ground for many fish that are commercially important Estuaries

Marine Ecosystems The ocean is divided into segments based on depth, and distance from the shore. They are the Intertidal, Coastal, and Open Ocean zones.

Organisms are submerged at high tide, and exposed during low tide. • Regular and extreme temperatures for the animals • Battered by waves, and currents • Barnacles, and plant life secure themselves to rocks to protect themselves from harsh conditions. Intertidal Zone

What other animals live in the Intertidal zone?

Extends from low tide mark to the outer edge of the continental shelf • Relatively shallow area • Brightly lit water, and well supplied with nutrients that run off the land • Kelp forests, and coral reefs are important coastal communities, and they thrive in this zone because of the amount of nutrients. Coastal Zone

Beginning at the edge of continental shelf • 90% of the ocean is considered open • Can reach depths of up to 10,000 meters in the ocean trenches • Is divided into Photic and Aphotic Zones Open Ocean

Typically low in nutrients • Supports only the smallest types of phytoplankton • Photosynthesis occurs at the surface Photic Zone

Permanently dark • Food webs may be based on either food which falls from the photic zone or autotrophs which function using chemosynthesis • Organisms are exposed to cold temperatures, high pressure, and total darkness • Once thought to have no life, we now know that due to deep-sea vents life can be supported and live at this level Aphotic Zone

What kind of adaptions has this fish made in order to survive in its’ environment?

Aquatic Ecosystems