OCEAN WATER OCEAN LIFE Composition of Seawater Salinity

OCEAN WATER & OCEAN LIFE Composition of Seawater Salinity- total amount of solid material dissolved in water. * ocean = 35 parts per thousand Sources of Materials 1. Chemical weathering of rocks - runs off into rivers, then into oceans 2. Earth’s interior(volcanic eruptions)

Ocean Salinity

Affects on Salinity 1. Decreasing salinity - caused by rain and ice melting 2. Increasing salinity - caused by evaporation & freezing

Processes Affecting Salinity

Ocean Density *Density- mass per unit volume - density causes ocean water to rise or sink. Affects on Density 1. Salinity- higher salinity= higher density lower salinity = lower density 2. Temperature- high temp. = low density low temp. = high density

Ocean Temp. Variation 1. Surface - ocean’s surface temp. varies with the amount of sunlight. 2. Deep Water - temp. decreases from surface to seafloor. *thermocline- layer of ocean with changes in temp. (300 -1000 m) - stays around 0 C after 1000 m.

Thermocline

Ocean Density Variation Density increases from surface to seafloor. *pycnocline- layer of ocean with changes in density. - separates warm, low density water from cold, high density water

Pycnocline

Ocean Layering *layered by density 1. Surface Mixed Zone - warmest zone - affected by waves & currents 2. Transition Zone - area between warm & cold layers 3. Deep Zone - no sunlight, coldest layer

Ocean Zones

Marine Organisms * classified by where they live. Types 1. Plankton- organisms that drift with ocean currents. 2 Groups A. Phytoplankton - carry out photosynthesis B. Zooplankton - animal-like microogranisms

Plankton Phytoplankton Zooplankton

2. Nekton - organisms that can swim throughout the oceans. ex. - fish, squid, marine mammals

3. Benthos - organisms living on the ocean bottom. ex. – algae, seaweed, crustaceans

Marine Life Zones * Divided by: 1. Amount of sunlight 2. Distance from shore 3. Water depth Sunlight 1. Photic Zone- upper layer receiving sun. 2. Aphotic Zone- bottom layer with no sun.

Distance from Shore 1. Intertidal Zone - area where land & water meet. - affected by the tides 2. Neritic Zone - area from low tide line to Cont. Shelf. - nutrient rich 3. Oceanic Zone - the deep, open ocean - nutrient poor

Depth 1. Pelagic Zone - open ocean of any depth 2. Benthic Zone - any sea bottom surface - shallow or deep 3. Abyssal Zone - deep ocean floor - primarily abyssal plains

Marine Life Zones

OCEAN PRODUCTIVITY Primary Productivity - energy created by photosynthesis or chemosynthesis. Affected by: 1. Amount of sunlight 2. Amount of nutrients

Productivity in Temperate Oceans

Feeding Relationships Food chain- sequence of energy transfer in a single path. Food web- complex system of energy transfer. *Energy transfer is inefficient - less energy at top of food chain/web *Animals in a food web survive better than animals in a food chain.

Food Chain vs. Food Web

OCEAN CIRCULATION Ocean currents - masses of ocean water moving from one place to another. Types 1. Surface Currents - movements that flow horizontally - mostly caused by wind 2. Gyres - large, circular movement of water - caused by wind & Coriolis Effect

Ocean Surface Currents

3. Upwelling - rising of cold water to the surface - caused by wind pushing out warm water - brings up nutrients 4. Density Current - vertical current caused by sinking dense water CAUSED BY: 1. Decrease in temperature 2. Increase in salinity