1. Properties of Water Marine and Freshwater

2. 1. Temperature THE most important limiting factor. THE most important limiting factor. A change in temperature can change other parameters. A change in temperature can change other parameters. Surface water is heated by the sun and changes seasonally. Surface water is heated by the sun and changes seasonally.

4. A narrow zone called a thermocline separates warm surface water from cool bottom water. A narrow zone called a thermocline separates warm surface water from cool bottom water. Divers can feel temperature differences as they go through this zone. Divers can feel temperature differences as they go through this zone. Whales use this zone for long distance communication…this channel is called the sofar channel Whales use this zone for long distance communication…this channel is called the sofar channel

5. THERMOCLINE

6. Sofar channel

7. Most marine animals are ectothermic. Warmer water temperature increases their metabolism. Most marine animals are ectothermic. Warmer water temperature increases their metabolism. However, warm water holds less Oxygen However, warm water holds less Oxygen Mammals and a few fish are endothermic…can usually maintain a constant body temp, but can suffer from hypothermia like we can. Mammals and a few fish are endothermic…can usually maintain a constant body temp, but can suffer from hypothermia like we can.

8. Sea surface temperature

9. Evaporation and condensation provide energy to run the hydrologic cycle; this energy reduces the possibility of freezing in marine organisms’ tissues. Evaporation and condensation provide energy to run the hydrologic cycle; this energy reduces the possibility of freezing in marine organisms’ tissues. Water also has a high heat capacity that allows it to absorb or release large quantities of heat with little temp change; this helps to moderate climates. Water also has a high heat capacity that allows it to absorb or release large quantities of heat with little temp change; this helps to moderate climates.

10. 2. Salinity Is the amount of dissolved solids in water Is the amount of dissolved solids in water Ions of chloride, sodium, sulfate, magnesium, calcium or potassium Ions of chloride, sodium, sulfate, magnesium, calcium or potassium The first 4 ions listed are remarkably constant in seawater. If chloride ions are measured, then the other ions can be calculated from it. The first 4 ions listed are remarkably constant in seawater. If chloride ions are measured, then the other ions can be calculated from it. Units are in parts per thousand (ppt) Units are in parts per thousand (ppt)

11. Surface salinity is GREATLY influenced by temperature. High temperatures cause increased evaporation rates and increase salinity. Surface salinity is GREATLY influenced by temperature. High temperatures cause increased evaporation rates and increase salinity.

12. The halocline is a zone where fluctuating surface salinity is divided from the constant salinity of deeper water. The halocline is a zone where fluctuating surface salinity is divided from the constant salinity of deeper water.

14. 3. Density Density = mass (g) / volume (ml) Density = mass (g) / volume (ml) Density is affected by temperature and salinity. Density is affected by temperature and salinity. Water is 800 times more dense than air. Sea water is more dense than fresh water. Water is 800 times more dense than air. Sea water is more dense than fresh water. Above the freezing point, the density of water is 1 gram/cubic centimeter. When water freezes, its density decreases because the volume increases. Above the freezing point, the density of water is 1 gram/cubic centimeter. When water freezes, its density decreases because the volume increases.

15. Ice has a density of.92 g/cm 3 so it floats in water. Any object will float in water if its density is less than the density of water it is floating in.

16. Chemical Properties of Water 1. pH in sea water is closely associated with dissolved CO 2 1. pH in sea water is closely associated with dissolved CO 2 CO 2 is a reactant in photosynthesis and a product of respiration. It dissolves easily in sea water and is stored in marine shells and sediments. CO 2 is a reactant in photosynthesis and a product of respiration. It dissolves easily in sea water and is stored in marine shells and sediments. H 2 O + CO 2 = H 2 CO 3 Carbonic Acid— lowers the pH of the water H 2 O + CO 2 = H 2 CO 3 Carbonic Acid— lowers the pH of the water

17. Enzyme activities and the shapes of vital proteins require a stable pH. Enzyme activities and the shapes of vital proteins require a stable pH. Since mollusk’s shells are calcium carbonate, a decrease in pH could dissolve shells. Since mollusk’s shells are calcium carbonate, a decrease in pH could dissolve shells.

18. Dissolved Gasses 2. Dissolved nitrogen is the most common gas in the ocean because it dissolves from the atmosphere where there is 78%. 2. Dissolved nitrogen is the most common gas in the ocean because it dissolves from the atmosphere where there is 78%. It can’t be used by organisms until it is attached to oxygen—nitrogen fixation It can’t be used by organisms until it is attached to oxygen—nitrogen fixation Nitrogen fixation happens because of blue-green algae. Nitrogen fixation happens because of blue-green algae.

19. 3. Dissolved oxygen comes mostly from photosynthesis of marine plants and algae. 3. Dissolved oxygen comes mostly from photosynthesis of marine plants and algae. They produce over 50% of the total atmospheric oxygen. They produce over 50% of the total atmospheric oxygen. Marine animals need O 2 for respiration. Marine animals need O 2 for respiration. Below the thermocline, there is very little oxygen Below the thermocline, there is very little oxygen

20. 4. Carbon dioxide is highly soluble in sea water…which contains about 50x more CO 2 then the atmosphere. 4. Carbon dioxide is highly soluble in sea water…which contains about 50x more CO 2 then the atmosphere.

21. Effects of Light

22. Marine plants (autotrophs) make their own food by photosynthesis. Marine plants (autotrophs) make their own food by photosynthesis.

23. Marine food webs depend on light that either is absorbed or reflected as it enter the water. Marine food webs depend on light that either is absorbed or reflected as it enter the water. About 65% of the light energy is absorbed in the first 5 feet and can’t be used by autotrophs. About 65% of the light energy is absorbed in the first 5 feet and can’t be used by autotrophs. Red light is absorbed first. Red light is absorbed first. Blue light is transmitted best Blue light is transmitted best

24. Light is inversely proportional to depth…as you increase depth, you decrease light. Light is inversely proportional to depth…as you increase depth, you decrease light. The lighted layer is called the photic zone…only about 10% of the ocean The lighted layer is called the photic zone…only about 10% of the ocean The dark layer is the aphotic zone…90% of the ocean is dark The dark layer is the aphotic zone…90% of the ocean is dark

26. Turbidity Is the measure of the suspended or dissolved solids. Is the measure of the suspended or dissolved solids. The more sediments, the less light penetration and the poorer the visibility. Photosynthesis is reduced by turbidity. The more sediments, the less light penetration and the poorer the visibility. Photosynthesis is reduced by turbidity. Turbidity can be measured with a secchi disk. Turbidity can be measured with a secchi disk.

27. Pressure Pressure at sea level is the weight of air (14.7 lb/in 3 ) Pressure at sea level is the weight of air (14.7 lb/in 3 )