Introduction to Marine Biology Aquatic Science – Mrs. Walker and Mrs. Eilers The marine environment is divided into areas with homogenous physical characteristics and locations. I. Ocean Realms A. Benthic Realm: OCEAN BOTTOM from the intertidal zone to the deepest ocean basin floor 1. littoral system: ocean bottom of the continental shelf a. supralittoral zone: area almost always exposed, immersed only during periods of extremely high tides and storm surges Typical organisms: mollusks, small gastropods, crabs, etc.

b. eulittoral zone: (intertidal zone) alternately covered and uncovered by tides Typical organisms: clams, oysters, mussels

c. sublittoral zone: extends to the edge of the continental shelf and always covered with water Typical organisms: MANY species of small to medium-sized fish

2. deep sea system: rest of the ocean bottom 1. bathyal zone: meters 2. abyssal zone: meters 3. hadal zone: deeper than 6000 meters a. no light b. less food so not very biologically productive and most animals there are scavengers (big mouths and teeth, mouths pointed upward, etc.) c. lacks extreme environmental changes

B. Pelagic Realm: WATER HABITATS of the ocean 1. neritic system: water area over the continental shelf a. great variations in salinity, temperature, and other environmental conditions (runoff and evaporation) b. MANY varieties of life forms (nutrients from runoff and upwelling)

- euphotic zone(down to 200m in clear water): receives light penetration (permits photosynthesis) and 99% of all light is absorbed here a. shallow water region that surrounds most continents and islands b. high levels of nutrients so abundant life (including all alga and photosynthesizing protists)

- dysphotic zone: “twilight” area where the remaining 1% of light penetrates a. can go as deep as a kilometer in very clear water – still not enough light for photosynthesis - aphotic zone: depth with no light penetration a. organisms are adapted to a life of extreme darkness, cold and pressure b. organisms here depend on the photic zone plankton for food by eating organisms that feed directly on plankton

2. ocean system: remainder of pelagic realm a. biological desert (center of gyres, no upwelling) b. divided either by depth or light

II. Ecologic Relationships A. ecology: study of the interactions between organisms and their environment B. Marine Ecosystems have both biotic and abiotic components - The nature of life in a particular habitat is determined by the abiotic part (physical and chemical environment) C. environment: area and conditions in which an organism lives

D. Basic groupings of ocean organisms based on environment 1. benthic organisms: bottom dwellers Ex. Barnacles, oysters, worms, clams, starfish) 2. plankton: life forms that drift in surface waters (limited by weak mobility) - holoplankton: permanently plankton (copepods, diatoms) - meroplankton: temporarily plankton in the larval or egg stage (barnacles, oysters, sea urchins, starfish, etc.)

Most of the plankton live relatively short lives (weeks to months) and remain microscopic in size their entire lives. These are the permanent plankton, also called holoplankton. (Holo- from the Greek word holos meaning whole) Copepods are part of the holoplankton. These tiny animals swim rapidly using their feet as oars. Therefore, scientists named them copepods, which means “oar- foot” (from the Greek words kope=oar; podos=foot).

Diatoms are a major group of algae.

Others, however, are temporary plankton; living, feeding, and being eaten as part of the plankton community only during the first month or so after being spawned (hatched). These are called meroplankton. (Mero- from the Greek word meros meaning part)

a. phytoplankton: photosynthetic plant-like single celled algae - base of food chain and 80% of Earth’s oxygen - most important life in ocean - most live in euphotic zone (3-650ft.) Ex. Diatoms, dinoflagellate b. zooplankton: non-photosynthetic animals that feed on the phytoplankton - make energy from plankton available to all other organisms Ex. Copepods, krill, forams, radiolarian 3. nekton: swimming organisms (independent of current movement) - may spend all or part of their life in different habitats

tiniest of zooplankton, the Radiolaria and Foraminifera. Both are protozoans, related to the familiar amoeba. Foraminifera secrete porous shells of calcium carbonate (lime), while Radiolaria produce shells composed mainly of silica (sand). Radiolaria produce some of the most intricate and beautiful skeletons in all the animal kingdom.

E. niche: role of organism in an ecosystem: the space, food and other conditions an organism needs to survive and reproduce and how a species uses and affects its environment are all part of its niche 1. food chain: the sequence in which energy makes its way through an ecosystem a. beginning of any food chain is a producer b. 10% Law: only approximately 10% of the energy in a food chain is passed from one level to the next Reasons: - some food is not captured and eaten - some food that is eaten is not digested - energy is lost as heat to the environment as the organisms at each level use it in cellular respiration

2. food web: interrelationship of all of the food chains in an ecosystem. Most marine food webs have 3-4 trophic levels: energy steps Ex. TROPHIC LEVEL: 1st 2nd 3rd 4th 5th diatoms  copepods  anchovy  redfish  dolphin (producer) (1st order (2nd order (3rd order (4th order consumer) consumer) consumer) consumer)

III. Habitat: collection of niches in which an organism lives its life A. limiting factors of habitats: anything that limits the survival and productivity of organisms 1. density-dependant: available food, disease, etc. (self- regulating) 2. density-independent: does not affect the community any differently as numbers in the community rise and fall (temperature, salinity, light, etc.) 3. main limiting factor in marine ecosystems is lack of nutrients 4. greater variations in habitat results in fewer organisms

Organism: that one living thing all by itself Population: group of organisms all the same species Community: all of the different populations of organisms living together in the same habitat Ecosystem: biological community along with its environment

Symbiosis: Relationship between two species 1. Mutualism: both members benefit ex. Clownfish and sea anemone 2. Commensalism: one benefits with no effect on the other ex. Barnacles on whales 3. Parasitism: one benefits at the others expense ex. Tapeworm in gut of a whale

Biological Classification DomainKingdom (Animalia, Plantae, Fungi, Protista, Monera) PhylumClassOrderFamilyGenusSpecies The Genus and Species name come together to make the scientific name of an organism. ex. Octopus bimoculatus