Chapter 12, Problem 45A

Summary Introduction

To explain:

The reason for great species diversity in estuaries and coral reefs.

Introduction:

Biodiversity is a variety of life in an area that is determined by the number of species living in that area. It helps in maintaining a healthy biosphere and provides direct and indirect value to humans. Biodiversity increases the stability of an ecosystem. The number of different species and their relative abundance in a biological community is called species diversity.

Answer to Problem 45A

Abundance of food and oxygen are the reasons for species diversity in estuaries and coral reefs. There is lot of mixing of species in estuaries and coral reefs due to which many species are found here. The photosynthetic algae and other plants support a large number of species by providing oxygen and nutrients.

Explanation of Solution

Estuaries- These are transitional ecosystems formed where freshwater from a river or stream meets the saltwater from the ocean. They are places of transition- from freshwater to saltwater and from land to sea- that are inhabited by a wide variety of species. The dominant producers are algae, seaweeds and marsh grasses. Due to lot of detritus available many animals such as oysters, worms and crabs are found here. Mangrove trees in tropical estuaries form swamps. Many species of fishes and invertebrates like shrimp use estuaries as nurseries for their young ones. Waterfowl like ducks and geese depend on estuaries for nesting, feeding and migration resting places. The transitional ecosystem provide for sufficient nutrients and oxygen for many species to survive here. There is lot of mixing of land and sea creatures so the diversity is also increased.

Coral reefs- These are the world’s most diverse ecosystems. They are widely distributed in warm shallow marine waters. The main organisms in coral reefs are corals. The coral polyps have symbiotic relationships with algae. Other coral reef animals include microorganisms, sea slugs, octopuses, sea urchins, sea stars and fishes. There are plenty of photosynthetic algae which provide oxygen and nutrients to other animals. The coral provide protection and light to algae.