Adaptations to Living

in the Ocean

Adaptations of organisms to the

marine environment

Marine organisms have various adaptations for the conditions of the marine environment.

Let’s focus on a few of the adaptations that marine organisms possess for:

Flotation & Buoyancy

Salt Regulation

Temperature

Water Pressure

Oxygen

Adaptations to Stay Afloat

Some animals (ex:

Portuguese man-of-war)

secrete gases into a float

that enables them to stay at

the sea surface

Remember: Viscosity increases with

decreasing temperature. So, small organisms

float more easily in cold waters than warm

waters. In tropical waters, organisms have

appendages to keep them afloat.

Adaptations for Buoyancy Many species of fish have internal swim bladders

filled with gas that keep them neutrally buoyant

When a fish changes depth, it adjusts the gas

pressure in its swim bladder to compensate for

pressure change (gets smaller when swim deeper)

Adaptations to Salt Regulation

Marine fish have adaptations to maintain

body water…

Adaptations for Temperature Regulation Marine animals other than birds & mammals are

ectotherms so body temp is same as surroundings

Seabirds &

mammals are

endotherms & have

adaptations to

maintain body

temps in cold water.

Blubber (insulating

fat & connective

tissue) under their

skin

Adaptations for Pressure Many organisms do not have gas-filled cavities

or lungs.

Deep-diving marine mammals may have:

Streamlined bodies (to reduce drag)

high conc. of myoglobin (holds oxygen)

collapsible lungs

Adaptations to Obtain Oxygen Marine animals

need oxygen to survive

Many marine animals use gills to extract dissolved oxygen from seawater

Marine mammals must breathe air

Whales have blow holes

Can you think of any others?

We’ve highlighted only a sampling of the

adaptations that marine organisms have to

survive in the oceans. Can you think of any

others?