Presentation on theme: "Warm Up 2/11/09 Which of the following is NOT a process that decreases the salinity of seawater? a. icebergs melting c. runoff from land b. precipitation d."— Presentation transcript:
1 Warm Up 2/11/09Which of the following is NOT a process that decreases the salinity of seawater?a. icebergs melting c. runoff from landb. precipitation d. evaporationIn addition to salinity, what factor affects the density of seawater?a. salt content c. latitudeb. temperature d. depthOcean salinity is usually expressed in ____.a. charts c. parts per thousandb. chemical formulas d. parts per billionAnswers: 1) d. 2) b. 3) c.
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 movePlankton include all organisms—algae, animals, and bacteria—that drift with ocean currentsPhytoplankton – the algae that undergo photosynthesisZooplankton – animal planktonNekton include all animals capable of moving independently of the ocean currents, by swimming or other means of propulsionThe term benthos describes organisms living on or in the ocean bottom
7 Marine Life ZonesThe distribution of marine organisms is affected by the chemistry, physics, and geology of the oceanThree factors are used to divide the ocean into distinct marine life zones: the availability of sunlight, the distance from shore, and the water depth
8 Availability of SunPhotic Zone – the upper part of the ocean into which sunlight penetratesThe clarity of seawater is affected by many factors, including the amount of plankton, suspended sediment, and decaying organic particlesThe 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 Concept CheckWhat is the difference between the photic zone and the aphotic zone?Sunlight penetrates the photic zone; no sunlight reaches the aphotic zone.
11 Distance from ShoreIntertidal Zone – the area where the land and ocean meet and overlapThe intertidal zone is a narrow strip of land which is alternately covered and uncovered between high and low tidesNeritic Zone – covers the gently sloping continental slopeThe 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 fisheriesOceanic Zone – area beyond the continental shelfSurface waters in the oceanic zone tend to not have many nutrients as they sink down to the deep ocean floor
13 Water Depth Pelagic Zone – open ocean of any depth Animals in the pelagic zone swim or float freelyBenthic Zone – includes any sea-bottom surface regardless of its distance from shoreThe benthic zone is mostly inhabited by benthos organismsAbyssal Zone – a subdivision of the benthic zone; includes the deep-ocean floor, such as abyssal plainsThe abyssal zone is characterized by high water pressure, consistently low temperature, no sunlight, and sparse life
16 Hydrothermal VentsSeawater seeps into the ocean floor through cracks in the crustThe water is super-heated and saturated with minerals, and escapes back into the oceanThe minerals precipitate out, giving the water the appearance of black smoke (black smokers)At some hydrothermal vents water temperature of 100ºC or higher support communities of organisms found nowhere else in the world