1. The Marine Environment
How physical and chemical properties of water affect life in the sea
The Marine Environment

2. The Marine Environment
Salinity
Seawater contains a variety of dissolved solids
Open ocean salinity can range from 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. The Marine Environment
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
More on this when we discuss Estuaries..
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. The Marine Environment
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 + 6CO C6H12O6 (Glucose) + 6O2
The Marine Environment

9. The Marine Environment
Oxygen Consumption
Aerobic respiration
Respiration in the presence of oxygen
Anaerobic respiration
Respiration in the absence of oxygen
The Marine Environment

10. The Marine Environment
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
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. The Marine Environment
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. The Marine Environment
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. The Marine Environment
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. The Marine Environment
Competition
Competition: refers to the interaction between organisms for a necessary and limiting resource
Light, food, water, and space
Barnacle 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. The Marine Environment
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. The Marine Environment
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
The Marine Environment