15.1: Marine Communities in Benthic Environments

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Miracosta Oceanography 101
Miracosta)

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Marine Communities in Benthic Environments

This chapter focuses on animals that are grouped as lower-level organisms in the benthic environment, specifically invertebrates —most of which are benthic animals that live attached on or near the seabed in the open ocean or coastal marine environments. The next Chapter 16 focuses on vertebrates and life in the pelagic environment.

Review: General classifications of Living Things

Taxonomy is the system of classifying and naming organisms (reviewed in Chapter 2). Carolus Linnaeus was first to development of a hierarchical system of classification of nature (biological organisms, present and past) .

Today, this system includes seven taxa: kingdom, phylum, class, order, family, genus, and species. (These are constantly being split into additional taxa levels as discoveries are made. Look at the example of humans.

Taxa							Example: Taxonomy of Humans
kingdom							kingdom: Animalia
	phylum						phylum: Chordata (subphylum: vertebrata)
		class					class: Mammalia (subclass: Theria) (Infraclass: Eutheria)
			order				order: Primates (suborder: Anthropoidea)
				family			(superfamily: Hominidae) family: Hominidae
					genus		Homo
						species	sapiens

Domains of life — Figure 16.1. Bioscientists are constantly reclassifying life forms as discoveries and new information becomes available. The term **domain** has been added to apply to **super kingdoms** subdivision status based largely on modern discoveries in microbiology - still under debate!This figure shows one of the more complex diagrams showing all the current know domains and lineages of life forms on Earth.

Kingdoms of Life

KINGDOMS	Examples
Monera	Bacteria/algae (more complex classification of monera is illustrated in Figure 16.1)
Protista	Forams/amoebas
Fungi	Mushrooms, molds
Plantea	Ferns, mosses, flowering plants (all are Autotrophs, photosynthetic)
Animalia	includes Invertebrates and invertebrates (all are Heterotrophs)

What is a Benthic Community?

• A benthic community is an area where a group of marine organisms live and interact with each other on, near, or within the seafloor (or in any water setting including lakes and rivers).

Benthic or benthos means “relating to, or occurring at the bottom of a body of water (oceans, lakes).“

Benthic environments include:
• littoral (includes shore or nearshore)
• neritic (seabed in shallow ocean/continental shelf)
• limnetic (pertaining to lakes)
• estuarine (pertaining to transition from river to ocean settings)
• sub-littoral (Below the littoral zone to a depth of 200 meters)
• sub-neritic (below 200 meters, include continental slope, continental rise, abyssal plain and trench settings).

Figure 15.1. Shells collections from shorelines reveal information about benthic communities.