This chapter focuses on the physical, chemical, and biological factors affecting marine communities in the oceans and coastal waters.
What is a Marine Community?
A marine community is an area where a group of marine organisms live and interact with each other. An ecosystem is defined as a community involving the interactions or interrelationships of living and nonliving things in an area. Marine ecosystems have distinct groups of organisms and have characteristics that result from unique combinations of physical factors that create them. A habitat is the natural home of an organism. Some species can adapt to a variety of environmental settings. Ecology is the branch of biological sciences that deals with their relationships of organisms with one another and to the physical environments where they are observed.
Marine communities include different feeding (trophic) levels:
|Primary producers||include photosynthetic bacterial - plankton - plants (discussed in Chapter 13)|
|Primary consumers||herbivores (zooplankton)|
|Secondary consumers||carnivores and detritus feeders (i.e., small fish, crustaceans)|
|Tertiary consumers||carnivores (larger animals, i.e. tuna, sharks, birds, sea mammals, etc)|
The term food chain is defined the hierarchical series of organisms that are each dependent on the next as a source of food. However, nature provides complexity that is better explained as a food web. A food web may have a variety of food chains that move energy and nutrients through an ecosystem. For instance, small or microscopic offspring may start as primary or secondary consumers when they are small, but they may become tertiary consumers if they survive to become large adult forms.