The Marine Environment 1

The Marine Environment

How physical and chemical properties of water affect life

in the sea

The Marine Environment 2

Salinity Seawater

contains a variety of dissolved solids

Open ocean salinity can range from 34 - 37 parts per thousand

Salinity is measured: Conductivity of Cl-

Refractometer

The Marine Environment 3

How salinity affects marine organisms

Most marine animals are adapted to a narrow salinity range Changes is salinity effect organisms through osmosis

Hyperosmotic solution- water will flow into it across a semipermeable membrane

Hypoosmotic solution - water will leave the solution

The Marine Environment 4

How to Cope Osmoconformers

Allows its internal salt concentration to change with the salinity of the surrounding water

Some molluscs & polychaete worms

Osmoregulators Keeps its internal salt concentration

constant regardless of the water salinity Many fishes & crabs

The Marine Environment 5

Temperature Regulation Homeotherms (Endothermic) - organisms which

regulate their internal body temperature regardless of the environment

Poikilotherms (Ectothermic) - organisms which have an internal body temperature that conforms to the environment

The Marine Environment 6

Temperature Stratification Thermocline is an area in

the water column of rapidly changing water temperature Thermoclines are most

prominent during the warmer months due to solar radiation and weak mixing

After the thermocline the water is an almost constant temperature

The Marine Environment 7

Methods for Measuring Temp.

Niskin Bottles

Satellite Imagery

The Marine Environment 8

Dissolved Gases Dissolved Gases

For living things the three most important dissolved gases are oxygen (O2), carbon dioxide (CO2) and nitrogen (N2)

The amount of a given gas that can dissolve decreases with an increase in temperature

The amount of oxygen in a body of water depends on: Mixing with the atmosphere Respiration Photosynthesis

Sunlight + 6H20 + 6CO2 C6H12O6 (Glucose) + 6O2

The Marine Environment 9

Oxygen Consumption Aerobic respiration

Respiration in the presence of oxygen Anaerobic respiration

Respiration in the absence of oxygen

The Marine Environment 10

Light Light is crucial for

photosynthesis and is strongest in the surface waters

Light attenuates with depth in an exponential fashion

UV light can be damaging to the proteins and DNA of many surface organisms

Effective light penetration can vary from 10-1,000m.)

The Marine Environment 11

Turbidity and Light Penetration Turbidity

The amount of solid particles suspended in the water column

Important since plants and algae need light for photosynthesis

Increase turbidity can decrease the amount of light which effectively penetrates

Large concentrations of phytoplankton can decrease light penetration (greenish tint)

The Marine Environment 12

Pressure Animals that live on land or

sea level are at 1 ATM (14.7 psi) With an increase in depth of

10 meters (33 ft) pressure is increased by 1 ATM.

Gas filled structures will shrink or collapse with depth

At the ocean’s avg. depth (3,700 meters) pressure is 2.7 tons per square inch

The Marine Environment 13

Properties of Water Water is more dense

and viscous than air Since it is a more

supportive medium there is not a need for a strong supportive skeleton

Also, an important consideration when we discuss sinking rates and movement through water

Surface tension

The Marine Environment 14

Ecological Principles

Interactions among animals and the environment

The Marine Environment 15

What is Ecology? A combination of biotic and abiotic factors

Biotic

Predator-prey interactions

Symbiotic relationships

Competition

Species interactions

Abiotic

Salinity

Temperature

Pressure

Non-biological factors

In the real world these factors are not easily separated

The Marine Environment 16

Ecological Principles Ecology: the

interactions of animals with each other

Habitat: the environment where an organism occurs Habitat can vary in

temperature, salinity, tides, and currents

The Marine Environment 17

Key Ecology Terms Species: natural group of interbreeding

individuals, which are reproductively isolated from other groups

Population: all the species in a given area Community: several populations, which

occur in an area Ecosystem: a series of communities and the

surrounding environment

The Marine Environment 18

Competition Competition:

refers to the interaction between organisms for a necessary and limiting resource Light, food, water,

and spaceBarnacle and mussels compete for space

The Marine Environment 19

The Results of Competition Natural selection: production of offspring by

the best-adapted individuals in a population Evolution: a change in the genetic makeup

of a population To be successful a species must find the

right balance between specialization and generalization Niche: the role a species plays in the community

The Marine Environment 20

Predation Predation is the

act of one animal eating another Coevolution - the

predator evolving in response to adaptations of the prey, or vice versa

The Marine Environment 21

Living Together Symbiosis

Commensalism

Mutualism

Parasitism Ectoparasites Endoparasites

The Marine Environment 22

Ocean Ecosystem Components

Autotrophic: organisms which capture energy to make organic matter Producers

Heterotrophic: organisms that capture energy by eating Herbivores - eat strictly producers Carnivores or piscivores - eat meat or fish Omnivores - generalists Apex predators - top predators