Section 3.2: Biomes *Biomes - a large group of ecosystems that share the same type of climax community. 2 types: 1) Aquatic Biomes 2) Terrestrial Biomes I.Aquatic Biomes: Life in the Water *2 types of aquatic biomes exist: freshwater and saltwater.

A.Marine (Saltwater) Biomes *different parts of ocean waters differ in physical factors and in the organisms found living there. *salinity - the amount or concentration of salt in the water. 1. Biomass - the oceans contain the largest amount of biomass compared to all other biomes; the majority of this biomass comes form extremely small organisms such as phytoplankton and zooplankton.

Plankton Phytoplankton - can do photosynthesis; very small, most are microscopic Zooplankton - cannot do photosynthesis, thus they eat other organisms, mainly phytoplankton.

2. Concept of “Zoning” Ecologists study marine biomes by separating them into 2 main zones: Photic & Aphotic. a) Photic Zone - zone or portion of the ocean that is shallow enough for sunlight to penetrate through. location - found in areas along the coastline and the upper portions of the sea.

b) Aphotic Zone - zone or portion of deep ocean water that NEVER receives sunlight. location - deepest parts of the oceans

B. A Mixing of Waters: Bays & Estuaries *rivers will often flow into the oceans and the two types of waters will mix. 1. Estuary - a coastal body of water, partially surrounded by land, where freshwater and saltwater merge.

a) Salinity in an estuary - salinity ranges from that of seawater to that of freshwater. It depends on how much freshwater is brought in by the river to the estuary. b) organisms in estuaries - due to changes in salinity of the estuary they are capable of supporting a large number and wide range of organisms. c) estuary ecosystems - salt marshes, bays

C. The Effects of the Tides *Tides are caused by the gravitational pull of the sun and the moon. 1. The Intertidal Zone - the portion of the shoreline that lies between the high and the low tide lines. The Zone size depends on: a) the slope of the land b) the height of the tide

2. The Intertidal Ecosystem a) has high levels of sunlight, nutrients and O 2 b) Productivity - limited by waves crashing against shore c) Organisms: 1) “suction cup” organisms ex) snails, sea stars 2) “glue” organisms ex) mussels, barnacles 3) “burrowing” organisms ex) clams, worms, crabs

Intertidal Zone Organisms: d) waves - keeps the bottom of the ocean in constant motion 3. Tide Pools *form when water recedes at low tide; marine “puddles” *this land locks some organisms until the next high tide

Zoning in the Ocean:

D. In the Light (Photic Zone) *the further out in the ocean you go, the less the ocean bottom is affected by waves. 1. Life - abundant in the photic zone; productivity is high. 2. Plankton - represents the majority of the ocean’s organisms. Can be autotrophic or heterotrophic. E. In the Dark (Aphotic Zone) *almost 90% of the ocean is more than a kilometer deep. 1. Life - depends upon plankton from above for food.

2. Adaptations to Life in the Dark -no photosynthesis; no light, cannot make food -special adaptations ex) large eyes, or no eyes at all bioluminescence

Freshwater Biomes *examples: rivers, ponds, lakes, streams, etc. 1. Organisms - cattails, sedges, tadpoles, aquatic insects, worms, crayfish, fish, etc.

Freshwater Biomes 2. Abiotic Factors: a) temperature variations: 1) upper surface of lake is warmer than lower or deeper portions of water. 2) the deeper you go, the colder it gets.

Freshwater Biomes b) light: 1) upper layer of freshwater systems receive enough light to carry out photosynthesis. 2) deeper portions of freshwater systems do not usually support photosynthesis. 3) not many plants can grow near the bottom if there is no light, thus populations density is lower near the bottom.

c) decay/ decomposition: 1) occurs on the bottom of the freshwater system; where the dead “stuff” accumulates. “Slimy” II. Terrestrial Biomes *Environments change as you move N to S *There is an observable pattern in the environments as you move N to S *Three (3) influential factors determine Biomes: 1) latitude 2) altitude 3) precipitation

Biome Map