1. LIFE IN THE OCEAN

2. Limiting Factors A limiting factor is a factor found in the environment that can be harmful if present in quantities that are too large or too small. Any factor required for life can become a limiting factor.

3. PHYSICAL FACTORS AFFECTING MARINE LIFE  light  dissolved gases  temperature  acid-base balance  salinity  hydrostatic pressure  dissolved nutrients

4. Light

5. Temperature Many ocean animals are ectothermic or “cold blooded” Can only tolerate certain ranges of temperatures Endotherms can tolerate greater ranges of temperature Temperature ranges in the ocean are less than those on land

6. Temperature vs Latitude

7. Temperature vs Depth

8. Salinity Salinity can affect density and therefore the buoyancy of an organism Salinity can alter the water balance in a cell

9. Salinity vs Latitude

10. Salinity vs Depth

11. Dissolved Nutrients Nutrients are required for the production of organic matter Most are limited in the ocean Most are easily depleted by organisms Can be returned through decomposition

12. Nitrates

13. Nutrients

14. Dissolved Gases Most important are oxygen and carbon dioxide Oxygen does not easily dissolve Carbon dioxide: 50 mL/L water at surface Oxygen: 6 mL/L water at surface

15. Deep water more carbon dioxide than surface Low oxygen levels at surface can cause animal deaths, especially at night while plants respire Gasses more variable closer to coast

16. Dissolved Oxygen

17. Hydrostatic Pressure: experienced due to the constant weight of water above the animal Not a problem as internal pressure equals external At great pressure, some enzymes become inactivated and metabolic rates increase Not a big deal unless the organism has gas filled places in its body

18.  feeding relationships  crowding  metabolic wastes  defense of territory BIOLOGICAL FACTORS AFFECTING MARINE LIFE

19. Diffusion is mixing due to random molecular movements. Diffusion, Osmosis and Active Transport

20. Osmosis is diffusion of water through a membrane

21. Active transport is the transport of a substance against a concentration gradient. Active transport requires energy input.

22. For marine organisms, internal concentration pretty much equals external concentrations This is why marine organisms, for the most part, cannot survive in freshwater

23. Gravity and Buoyancy Weight of marine organisms is mostly balanced by sea water Some fish have gas filled bladders to allow them to rise and sink

24. Deep water fish have light weight bones and oily flesh Fast swimming fish have no need of swim bladders - skeletons are used for mobility, not strength, so it can be lightened

25. Ammonium chloride is replaced by lighter seawater in some critters Some produce oils and waxes or projections to help them float Cold water is more dense than warm

26. Viscosity and Movement Cold water is more viscous than warm Higher salinity = more viscosity Large organisms are affected due to drag Some fish secrete mucus to reduce drag, some tuck their fins into their bodies Small organisms have trouble swimming through viscous water