Aquatic & Fisheries Ecology

1. Aquatic & Fisheries Ecology

2. Aquatic & Fisheries Ecology • Aquatic = taking place in or on water • Fishery = the occupation, industry, or season of taking fish or other aquatic animals (Focus = human use.) • Ecology = the study of interactions of organisms with other organisms and with the abiotic environment

6. Earth’s Surface • 71% water; 29% land • Water Volume • 96.5% = ocean • 1.8% = glacial ice • 1.7% = groundwater • 0.014% = lakes/streams • 0.001% = atmosphere

7. Water (H20) Characteristics • Polar = (+ & -) ends. • H-bonds connect molecules; so liquid at “room” temp. & has high specific heat. (more energy to change temp.) • Polar & ionic molecules dissolve well in water. • Boils at 100°C; freezes at 0°C Most dense at 4°C • Solid H2O less dense than liquid H2O

8. pH – Acidity & Alkalinity H2O ↔ H+ + OH- H2O + CO2 ↔ H2CO3 ↔ H+ + HCO3- • ↑H+ = acid (pH<7); ↓H+ = base (pH>7) • pH of rain ≈ 5.6 – because of CO2 in air H2O + CO2 → H2CO3 → H+ + HCO3- • Alkalinity = the ability of a solution to neutralize (buffer) acids (≠ high pH) -usually accounted for by HCO3-conc. H2O + CO2 ← H2CO3 ← H+ + HCO3- • freshwater pH = 5.5-8.5 • seawater pH ≈ 8.0 (high HCO3- /alkalinity)

9. Salinity • Salinity = the total amount of dissolved material in water (Na+, K+, Mg2+, Ca2+, & Cl-, Br-, HCO3-, CO32-) Difficult to measure accurately – milligrams per liter (mg/l), parts per thousand (‰), or conductivity in Siemens per centimeter. Practical Salinity Scale = salinity measured electronically without units • Chlorinity = grams per kilogram Cl- Salinity ‰ = 1.806 x Chlorinity ‰

10. Salinity Marine salinity ≈ 35 (32-37) (≈ 35‰) Brackish salinity = 0.5-32 Freshwater salinity ≈ 0.12 (<0.5) Hypersaline waters >37 Source of salts – rock weathering (most ions); volcanic activity (source of most Cl-) Salts concentrated in the world ocean (or isolated terrestrial basins)

11. Hardness • Hardness = mg per liter of Ca2+ & Mg2+ soft water = <17.1 mg/l hard water = ≥17.1 mg/l Primarily concerned with CaCO3 (“limestone”). Hard water = greater buffering capacity.

12. Chemical Processes light energy 6O2+ C6H12O6 ATP energy photo- synthesis glycolysis + cell. respiration OH- + H+ inside a cell H2O + CO2 H2CO3 H++ HCO3- 6H2O+ 6CO2 2H+ + CO32- Ca2+ CaCO3 solid (limestone)

13. Gas Solubility • N2 = 48% of gases in seawater. (78% of atmos.) • CO2 = 15% of gases in seawater AS CO2. (0.03% of atmosphere) Most CO2 enters carbonate buffer system, because of this CO2 is incredibly soluble. • O2 = 36% of the dissolved gases in seawater. (21% of gases in atmosphere; 100x more in atmos.) O2 & CO2 solubility decreases as temp. & salinity increase, AND increases as pressure increases.

14. Dissolved Gas Concentration • ABIOTIC determinants Temperature Salinity Pressure • BIOTIC determinants Photosynthesis – Can increase O2 and decrease CO2 greatly (sometimes to O2 supersatuation… forming bubbles). Glycolysis & Cellular Respiration – Can increase CO2 and decrease O2 greatly (sometimes to the point of anoxia).

15. Relationships Increasing salinity… • decreases gas solubility • decreases heat capacity • lowers freezing point • increases energy for evaporation Increasing temperature… • decreases gas solubility • increases ion solubility

16. Light Penetration • Light important for photosynthesis. • Light does not penetrate water as well as air. (Reds are first “filtered out” by water, blues last.) • Turbidity= amount of suspended material in the water (“cloudiness”) More turbid = lower penetration of light. • Higher turbidity and greater depth = less light over all Greater depth = less red wavelength light

17. Stratification • Thermocline= rapid change in temperature at a specific narrow range of depth • Halocline= rapid change in salinity at a specific narrow range of depth • Pycnocline= rapid change in density at a specific narrow range of depth (If present, it corresponds to thermocline & halocline.)

18. crest wavelength wave height trough Waves • Waves occur when energy is transferred to the water from above or below. wind (surface); earthquake (bottom) • Energy is transferred efficiently among H2O molecules. http://www.classzone.com/books/earth_science/terc/content/visualizations/es1604/es1604page01.cfm?chapter_no=visualization wind

19. Waves • Swell = “mature”, regular, rounded waves.

20. crest trough Waves • Waves dampened by... H2O molecule cohesion – small waves Gravity – large waves • Wave formation from vigorous energy input often causes peaked crests. Top moves faster than bottom. wind

21. Breaking Waves • Breaking Wave= “top” of wave falls over bottom of wave. • Wave “feels” the bottom at ½ wavelength.

22. Breaking Waves http://www.youtube.com/watch?v=5iN_Cs0Mdfg&feature=related

23. Internal Waves • If the thermo/pycnocline is very narrow, internal waves can develop between the the two layers. • Internal waves in the deep, dense layer move much more slowly than surface waves in air. • Internal waves can form regular slicks of downwelling water above the wave troughs. • Slicks can concentrate plankton.

24. Internal Waves slick LESS DENSE MORE DENSE

25. Internal Waves

26. Internal Waves

27. Regions of a Body of Water • Benthic = on, at, or associated with the bottom • Pelagic = in or associated with “open water” away from the bottom.

28. Substrate/Sediment • Substrate = the “bottom” of a body of water • Sediment = particles that accumulate to form a loose substrate. Boulders =>25.6 cm Cobbles Pebbles/Gravel Sand Silt Clay =<0.004 mm • Detritus =fragments of dead photosynthesizers

29. Hydrologic Cycle

30. Ocean Interface

31. Groundwater • Groundwater = water under the surface of the soil (Surface Waters = above the surface) • Water Table =The vertical extent of water saturated soil and/or rock • Aquifer =Water contained within porous rock (Contained Aquifer = below water impermeable rock) • Groundwater “Recharge” =entry of surface water into groundwater http://www.youtube.com/watch?v=uQRvN6MUajE

32. Freshwater System

33. Ogallala Aquifer

34. Ocean Profile continental shelf continental slope abyssal plain

35. World Ocean Basin

36. Surface Ocean Currents • Gyre = a large system of rotating currents (5 large global gyres); mostly from winds • N. hemis. = clockwise; S. hemis. = counter http://www.youtube.com/watch?v=Hu_Ga0JYFNg

37. Ocean Conveyor Belt • Conveyor Belt = a large scale global water circulation driven by density

38. Upwelling & Downwelling • Upwelling = colder denser water comes near surface. -coastal upwelling -equatorial upwelling -“deep current” upwelling

39. Upwelling & Downwelling