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CH 15 Ocean Life and Ocean Water. Salinity – total amount of dissolved solids in water Expressed in parts per thousand Average salinity of is 35 ppt or 3.5 % 2 main dissolved solids Chlorine = 55 % from earth’s interior (volcanoes)
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CH 15 Ocean Life and Ocean Water • Salinity – total amount of dissolved solids in water • Expressed in parts per thousand • Average salinity of is 35 ppt or 3.5 % • 2 main dissolved solids • Chlorine = 55 % from earth’s interior (volcanoes) • Sodium = 30.6 % from chemical weathering of rocks carried by rivers
Processes Affecting Salinity • Oceans are well mixed • Percentages of major components in sea water are constant, but salinity varies from 33 – 38 ppt • Precipitation decreases salinity • Runoff from land decreases • Icebergs melting decreases • Evaporation increases • Formation of sea ice increases
Ocean Variations • Temperature • Mostly a function of latitude • A function of depth, too • Thermocline – rapid change in temp as depth changes • Only found in low latitudes • Density • Higher salinity = higher density • Lower temps = higher density • Deeper = more dense • Pycnocline – rapid change in density as depth changes • Only found in low latitudes
Ocean Layering • Most parts of the open ocean have a 3 layered structure • Surface zone – warmest; photosynthesis; mixed zone due to waves, currents, and tides; mostly constant temperatures • Transition zone – thermocline: pycnocline; halocline • Deep zone – abyss; very cold, very high pressures, and very dark
Ocean Life • Marine organisms are classified according to where they live and how they move • Plankton – drift with ocean currents • Phytoplankton/plant and zooplankton/animal • Nekton – all animals that can swim/move on their own • Fish, squid, turtles • Benthos – living on or in the ocean bottom • Worms, coral, starfish
Marine Life Zones • 3 factors to divide oceans into marine life zones • Availability of sunlight • Photic; euphotic; aphotic • Distance from shore • Intertidal, neritic, oceanic • Water depth • Pelagic, benthic, abyssal
Other Ocean Stuff to Learn • Hydrothermal vents • Coral reefs • Abyssal creatures • Sharks
Oceanic Productivity • Primary productivity – Production of organic stuff from inorganic stuff… • Photosynthesis - • Chemosynthesis – bacteria and H2S • Productivity in polar oceans • Seasonal variation • Salt concentrating nutrients • Limit of available sunlight
Productivity in tropical oceans • Sunlight penetrates far • Thermocline prevents mixing • Lack of nutrients limits production • Productivity in temperate oceans • Sunlight and nutrient supply limit productivity • Each season has its effect • Spring is when the big bloom occurrs.
Oceanic Feeding Relationships • Trophic levels • Feeding stages on a food pyramid • Herbivores and carnivores • Transfer efficiency • Energy transfer between trophic levels is very inefficient…usually about 2 %...wow • Food chains and food webs • Yada, yada, yada