Exploring Marine Life Zones: Classification and Characteristics

1. Warm Up • What is salinity? • The total amount of solid material dissolved in water • What is the difference between a thermocline and a pycnocline? • Thermocline- temp; pycnocline-density • What are the three different layers of the ocean? • Mixed Zone, Transition Zone, Deep Zone

2. The Diversity of Ocean Life Chapter 15, Section 2

3. Classification of Marine Organisms • Marine organisms can be classified according to where they live and how they move • Plankton include all organisms—algae, animals, and bacteria—that drift with ocean currents • Phytoplankton – the algae that undergo photosynthesis • Zooplankton – animal plankton • Nekton include all animals capable of moving independently of the ocean currents, by swimming or other means of propulsion • The term benthos describes organisms living on or in the ocean bottom

4. Plankton Phytoplankton Zooplankton

5. Nekton

6. Benthos

7. Give an example of a nekton.

8. Marine Life Zones • The distribution of marine organisms is affected by the chemistry, physics, and geology of the ocean • Three factors are used to divide the ocean into distinct marine life zones: the availability of sunlight, the distance from shore, and the water depth

9. Availability of Sun • Photic Zone – the upper part of the ocean into which sunlight penetrates • The clarity of seawater is affected by many factors, including the amount of plankton, suspended sediment, and decaying organic particles • The euphotic zone is the portion of the photic zone near the surface where light is strong enough for photosynthesis (usually no deeper than 100 meters) • Below the photic zone is the aphotic zone, where there is no sunlight

10. Distance from Shore • Intertidal Zone – the area where the land and ocean meet and overlap • The intertidal zone is a narrow strip of land which is alternately covered and uncovered between high and low tides • Neritic Zone – covers the gently sloping continental slope • The neritic zone is often shallow enough to put all of it in the photic zone, and is so rich with life that it supports 90% of the world’s commercial fisheries • Oceanic Zone – area beyond the continental shelf • Surface waters in the oceanic zone tend to not have many nutrients as they sink down to the deep ocean floor

11. Water Depth • Pelagic Zone – open ocean of any depth • Animals in the pelagic zone swim or float freely • Benthic Zone – includes any sea-bottom surface regardless of its distance from shore • The benthic zone is mostly inhabited by benthos organisms • Abyssal Zone – a subdivision of the benthic zone; includes the deep-ocean floor, such as abyssal plains • The abyssal zone is characterized by high water pressure, consistently low temperature, no sunlight, and sparse life

12. Marine Life Zones

13. Marine Life Zones

14. Hydrothermal Vents • Seawater seeps into the ocean floor through crack in the crust • The water is super-heated and saturated with minerals, and escapes back into the ocean • The minerals precipitate out, giving the water the appearance of black smoke (black smokers) • At some vents water temperature of 100ºC or higher support communities of organisms found nowhere else in the world

15. Hydrothermal Vents

16. Assignment • Read Chapter 15, Section 2 (pg. 428-432) • Do Section 15.2 Assessment #1-7 (pg. 432)