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BIOL 4120: Principles of EcologyBIOL 4120: Principles of Ecology
Lecture 2: Lecture 2: Adaptation to Adaptation to Physical Environment: Water Physical Environment: Water
and Nutrientsand Nutrients
Dafeng HuiDafeng Hui
Office: Harned Hall 320Office: Harned Hall 320
Phone: 963-5777Phone: 963-5777
Email: [email protected]: [email protected]
Topics (Chapter 2):
2.1 Global water cycling 2.1 Global water cycling 2.2 Water has many properties favorable to life2.2 Water has many properties favorable to life2.3 Many inorganic nutrients are dissolved in 2.3 Many inorganic nutrients are dissolved in
water water 2.4 Plants obtain water and nutrients from soil2.4 Plants obtain water and nutrients from soil2.5 Maintain salt and water balance by plants and 2.5 Maintain salt and water balance by plants and
animalsanimals
Water is essential for life Water is essential for life (75-95% weight of living (75-95% weight of living cell)cell)
Over 75% of the EarthOver 75% of the Earth’’s s surface is covered by surface is covered by waterwater
• Oceans contain 97%.Oceans contain 97%.
• Polar ice caps and Polar ice caps and glaciers contain 2%.glaciers contain 2%.
• Freshwater in lakes, Freshwater in lakes, streams, and ground streams, and ground water make up less water make up less than 1%.than 1%.
(Saltwater and fresh (Saltwater and fresh water)water)
2.1 Global Hydrologic (water) cycle 2.1 Global Hydrologic (water) cycle between Earth and atmosphere between Earth and atmosphere
The The waterwater (or (or hydrologichydrologic) ) cyclecycle is is the process by which water travels in the process by which water travels in a sequence from the air to Earth and a sequence from the air to Earth and returns to the atmospherereturns to the atmosphere
Solar radiation is the driving force Solar radiation is the driving force behind the water cycle because it behind the water cycle because it provides energy for the evaporation provides energy for the evaporation of waterof water
Water Cycles between Earth and Water Cycles between Earth and the Atmospherethe Atmosphere
The Hydrologic CycleThe Hydrologic Cycle
Precipitation Precipitation (PPT)(PPT)
InterceptionInterception InfiltrationInfiltration Groundwater Groundwater
rechargerecharge RunoffRunoff Evaporation Evaporation
(E)(E) Transpiration Transpiration
(T)(T)
Distribution of water is not static (processes)
Global water budgetGlobal water budgetLand
Pools (10^3 km3):Glaciers: 29,000Groundwater:4,000Lake: 229Soil: 67
Fluxes (km3/yr):PPT: 111,000ET: 71,000River flow:40,000
Ocean
Pools: (10^3 km3)Ocean:1.37*10^6
Fluxes: (km3/yr)PPT:385,000ET: 425,000
2.2 Properties of water that favorable to 2.2 Properties of water that favorable to lifelife
Basic Structure 1. Covalent bonding of 2H + O atoms 2. Polar-covalent bond 3. Inter-molecule attraction 4. H-bonds among water moleculars
Physical and chemical propertiesPhysical and chemical properties Thermal properties of water: High specific heat Thermal properties of water: High specific heat
capacitycapacity 1.Specific Heat: 1.0 (also called Heat Capacity)1.Specific Heat: 1.0 (also called Heat Capacity)
• calories required to raise 1 g H2O 1calories required to raise 1 g H2O 1ooC C high high
• (e.g. from 10 to 11(e.g. from 10 to 11ooC) (Stable T in C) (Stable T in lakes and organisms)lakes and organisms)
2. Latent heat: energy released or absorbed in the 2. Latent heat: energy released or absorbed in the transformation of water from one state to another.transformation of water from one state to another.
1 calorie to raise 11 calorie to raise 1ooC; 536 calories to change 100C; 536 calories to change 100ooC C water to vapor; 86 calories ice to 1water to vapor; 86 calories ice to 1ooC waterC water
3. Peculiar density-temperature relationship3. Peculiar density-temperature relationship Density increases as T decreases (when T> 4Density increases as T decreases (when T> 4ooC), C),
then decrease to 0then decrease to 0ooC, freezing (ice), float.C, freezing (ice), float.
CohesionCohesionDue to the hydrogen bonding, water Due to the hydrogen bonding, water
molecules tend to stick firmly to each molecules tend to stick firmly to each other, resisting external forces that would other, resisting external forces that would break the bonds (drop of water, break the bonds (drop of water, transpiration).transpiration).
Surface tensionSurface tension
Strong attraction within Strong attraction within the water body and the water body and weaker attraction in the weaker attraction in the surface caused that surface caused that molecules at the surface molecules at the surface are drawn downward.are drawn downward.
High viscosity Viscosity: measures the force necessary to
separate the molecules and allow passage of an object through liquid.
Frictional resistance is 100 times greater than air.
Water is 860 times denser than air.• Organisms in water have similar density to Organisms in water have similar density to
water, the neutral buoyancy helps against the water, the neutral buoyancy helps against the force of gravity, thus require less investment force of gravity, thus require less investment in structure material such as skeletonsin structure material such as skeletons
• Organisms in deep water need to adapt to the Organisms in deep water need to adapt to the high pressure (20 to 1000 atm).high pressure (20 to 1000 atm).
2.3 Many inorganic nutrients are 2.3 Many inorganic nutrients are dissolved in waterdissolved in water
Solution: a homogeneous liquid with 2 or more substances mixed.
Solvent: dissolving agent
Solute: substance that is dissolved
Aqueous solution: water as solvent
Ions: Compounds of electrically charged atoms
Cations: positive
Anions: negative
Practical salinity units (PSU, o/oo): grams of salt per kilogram of water.
Ocean: 35 unit, Fresh water: 0.065-0.30 unit)
Hydrogen ions in ecological systemsHydrogen ions in ecological systems
Hydrogen ions are very active: 1) affect enzyme activities, and thus influence life processes; 2) dissolve minerals from rocks and soils.
Acidity: the abundance of hydrogen ions (H+) in solution.
Alkalinity: abundance of hydroxyl ions (OH-) in solution
Acidity in water is related to carbon dioxide (CO2).
Forms of carbon in waterForms of carbon in water Carbon-bicarbonate equilibriumCarbon-bicarbonate equilibrium
• Carbon dioxide:Carbon dioxide: CO CO22
• Carbonic acid:Carbonic acid: H H22COCO33
• Bicarbonate:Bicarbonate: HCO HCO33--
• Carbonate:Carbonate: CO CO332-2-
CO2 + H2O H2CO3 HCO3- + H+ CO3
2- + 2H+
Measurement: pH =-log([H+])
(value between 1-14) Pure water: 7 Acidic: <7 Alkaline: >7
Ocean water tends to be slightly alkaline with a pH range of 7.5-8.4
2.4 Plants obtain water and 2.4 Plants obtain water and nutrients from soilnutrients from soil
Plants and animals need water and Plants and animals need water and nutrients to growth and reproduce.nutrients to growth and reproduce.
Plants acquire the inorganic Plants acquire the inorganic nutrients as ions dissolved in waternutrients as ions dissolved in water
N: ammonium (NHN: ammonium (NH44++), nitrate (NO), nitrate (NO33--)) P: phosphate ions (POP: phosphate ions (PO443-3-)) K: KK: K++
Na: NaNa: Na + +
Ca: CaCa: Ca2+2+
The availability in soil is determined by The availability in soil is determined by their chemical forms in soil, their chemical forms in soil, temperature, acidity, and presence temperature, acidity, and presence of other ions. of other ions.
2.4.1 Ion exchange capacity is 2.4.1 Ion exchange capacity is important to soil fertilityimportant to soil fertility
Soil soluble nutrients are charged particles, Soil soluble nutrients are charged particles, ions. ions.
Cations: positively charged (CaCations: positively charged (Ca2+2+, Mg, Mg2+2+, , NHNH44
++))
Anions: negatively charged (NOAnions: negatively charged (NO33––, PO, PO33
4–4–))
Ions are attached to soil particles, so they Ions are attached to soil particles, so they do not leach out of the soil.do not leach out of the soil.
Ion exchange capacity: total number of Ion exchange capacity: total number of charged sites on soil particles in a charged sites on soil particles in a standard volume of soil.standard volume of soil.
Soils have an excess of negative Soils have an excess of negative charged sitescharged sites
Cationic exchange Cationic exchange dominant (colloids)dominant (colloids)
Cation exchange Cation exchange capacity (CEC): capacity (CEC): total # of total # of negatively charged sites, located on negatively charged sites, located on the leading edges of clay particles the leading edges of clay particles
and Soil Organic Matter.and Soil Organic Matter. Concentration and Concentration and
affinityaffinity
Al3+ > H+ > Ca2+ > Mg2+ > K+ = NH4+
> Na+
Process of cation exchange in soilsProcess of cation exchange in soils
In soils with high Mg++ or Ca++, K+ is lacking, why?
2.4.2 Soil properties and water-holding 2.4.2 Soil properties and water-holding capacitycapacity
TextureTexture• Variation in size and Variation in size and
shape of soil particlesshape of soil particles Gravel (NOT)Gravel (NOT)
• >2mm>2mm
SandSand• 0.05mm to 2mm0.05mm to 2mm
SiltSilt• 0.002mm to 0.002mm to
0.05mm0.05mm ClayClay
• <0.002mm<0.002mm
Soil texture is percentage of sand, silt and clay. (Texture chart)
Sand: 58%Clay: 14% Silt: 28%
Water holding capacity is an essential feature of Water holding capacity is an essential feature of soilssoils
Soil can become saturated if Soil can become saturated if all pores filledall pores filled
All water is hold by soil All water is hold by soil particulars, at field capacity particulars, at field capacity (FC) (FC)
Capillary water is usually Capillary water is usually present present • Extractable by plantsExtractable by plants
Wilting point (WP)Wilting point (WP)• Plant no long extract waterPlant no long extract waterAvailable water capacity Available water capacity
(AWC)(AWC)
All affected by soil textureAll affected by soil texture• Sand Sand
Lower capacityLower capacity• ClaysClays
Higher capacityHigher capacity
Water content at different soilsWater content at different soils
2.4.3 Water moves from soil to plant to atmosphere
Water potentialWater potential
Water moving between soil and plants Water moving between soil and plants flows down a water potential gradient.flows down a water potential gradient.
Water potentialWater potential ( ) is the capacity of water ( ) is the capacity of water to do work, to do work, potential energy of of water relative to pure water. relative to pure water. • Pure Water = 0.Pure Water = 0.
in nature generally negative.in nature generally negative. solutesolute measures the reduction in due to dissolved measures the reduction in due to dissolved
substances.substances.
Water potential of compartment of soil-plant-atmosphereWater potential of compartment of soil-plant-atmosphere
• w = p + o + m
• Hydrostatic pressure or physical pressure (cell wall).
• Osmotic potential: tendency to attract water molecule from areas of low concentrations to high. This is the major component of total leaf and root water potentials.
• Matric potential: tendency to adhere to surfaces, such as container walls. Clay soils have high matric potentials.
Water moves from soil to plant to atmosphere
The cohesion-tension theory explains the movement of water from the roots to a leaf of a plant.
1. Through Xylem2. No metabolic energy required3. Depends on physical-chemical properties of water, driven by water potential.
Stick to each other and adhere to cell wall.
BIOL 4120: Principles of EcologyBIOL 4120: Principles of Ecology
Lecture 2: Lecture 2: Adaptation to Adaptation to Physical Environment: Water Physical Environment: Water
and Nutrientsand Nutrients
Dafeng HuiDafeng Hui
Office: Harned Hall 320Office: Harned Hall 320
Phone: 963-5777Phone: 963-5777
Email: [email protected]: [email protected]
Recap:
Water propertiesWater propertiesMany inorganic nutrients are dissolved in water Many inorganic nutrients are dissolved in water
Nutrients, pHNutrients, pH
Plants obtain water and nutrients from soilPlants obtain water and nutrients from soil Soil and nutrient (CEC) Soil and nutrient (CEC) Soil properties and water (water holding Soil properties and water (water holding
capacity)capacity) Water movement from roots to plants to airWater movement from roots to plants to air
2.5 Maintenance of salt and water 2.5 Maintenance of salt and water balancebalance
To maintain proper amount of water and dissolved substances in To maintain proper amount of water and dissolved substances in their bodies, organisms must balance losses with intake.their bodies, organisms must balance losses with intake.
When organisms take in water with solute concentration differs When organisms take in water with solute concentration differs from that of their bodies, they must either acquire more solutes to from that of their bodies, they must either acquire more solutes to make up the deficit or get rid of excess solutes:make up the deficit or get rid of excess solutes:
Uptake of water with solutesUptake of water with solutes Evaporation from surface of terrestrial organisms into Evaporation from surface of terrestrial organisms into
atmosphereatmosphere Solutes left behind, high salt concentrationSolutes left behind, high salt concentration
Solutes determine osmotic potential of body fluids, the Solutes determine osmotic potential of body fluids, the mechanisms that organisms use to maintain a proper salt mechanisms that organisms use to maintain a proper salt balance are referred to as osmoregulation. balance are referred to as osmoregulation.
2.5.1 Management of salt balance 2.5.1 Management of salt balance by plantsby plants
Transpiration – water uptake – dissolved salts along water will get into roots
When salts concentrations in soil water are high, plants pump excess salts back into soil by active transport across their root surface, function as plant’s “kidneys”.
One example: Mangroves on coastal mudflats
Salt glands on the leaf surface
2.5.2 Water and salt balance in 2.5.2 Water and salt balance in terrestrial animalsterrestrial animals
TerrestrialTerrestrial• InputInput
DrinkingDrinking EatingEating Produced by metabolism (respiration)Produced by metabolism (respiration)
• Output Output –– Need to control in extreme environments Need to control in extreme environments UrineUrine
• Concentrated to avoid water loss (Kidneys). Human: 4 Concentrated to avoid water loss (Kidneys). Human: 4 times high than in blood; Kangaroo rat: 14 times times high than in blood; Kangaroo rat: 14 times
FecesFeces EvaporationEvaporation
• No sweat glands in some mammals; No sweat glands in some mammals; • ““salt glands” in birds and reptilessalt glands” in birds and reptiles
BreathingBreathing
What happens to ungulates in a hot What happens to ungulates in a hot dry climate like Africa?dry climate like Africa?
No pants, no sweating to save water, store heat in body (T up to 46oC at daytime, release heat at night 36oC)
Countcurrent heat exchange to lower head T
Eat at nighttime, more water in plants
Respiration to produce water
Oryx
• Freshwater (hyper-osmotic, high salt in Freshwater (hyper-osmotic, high salt in body)body)
Prevent excess uptake of waterPrevent excess uptake of water Remove excess waterRemove excess water
• Large amounts of very dilute urineLarge amounts of very dilute urine• Retain salt in special cells (gills, kidneys)Retain salt in special cells (gills, kidneys)
• Saltwater (hypo-osmotic, low salt in body)Saltwater (hypo-osmotic, low salt in body) If salt concentration is higher than in body, If salt concentration is higher than in body,
dehydratedehydrate• Drinking a lot to gain waterDrinking a lot to gain water• Some sharks: retain urea in the bloodstream (balance Some sharks: retain urea in the bloodstream (balance
body surface water loss)body surface water loss)• Ion pumps, gill (fish)Ion pumps, gill (fish)• Kidneys (eliminate salts, marine mammals)Kidneys (eliminate salts, marine mammals)• Salt secreting glands in birdsSalt secreting glands in birds
2.5.3 Water and salt balance in 2.5.3 Water and salt balance in aquatic animalsaquatic animals
The End
Proportions of the formsProportions of the formsof COof CO22 in Relation to pH in Relation to pH
pH CO2 HCO3– CO3
=
4 0.996 0.004 1.26 x 10-9
5 0.962 0.038 1.20 x 10-7
6 0.725 0.275 0.91 x 10-5
7 0.208 0.792 2.60 x 10-4
8 0.025 0.972 3.20 x 10-3
9 0.003 0.966 0.031
10 0.000 0.757 0.243
Free Bicarbonate Carbonate
Recap:
Water propertiesWater propertiesMany inorganic nutrients are dissolved in water Many inorganic nutrients are dissolved in water
Nutrients, pHNutrients, pH
Plants obtain water and nutrients from soilPlants obtain water and nutrients from soil Soil and nutrient (CEC) Soil and nutrient (CEC) Soil properties and water (water holding Soil properties and water (water holding
capacity)capacity) Water movement from roots to plants to airWater movement from roots to plants to air
Recap:
Physical environment: water and nutrient Physical environment: water and nutrient
Water propertiesWater properties Inorganic nutrients need to be dissolved in Inorganic nutrients need to be dissolved in
water, Nutrients uptake from soil water, Nutrients uptake from soil Ion exchange capacity is a measure of soil Ion exchange capacity is a measure of soil
fertilityfertility Soil texture and water holding capacitySoil texture and water holding capacity Water movement from soil to plant to Water movement from soil to plant to
atmosphereatmosphere
