I. I.Water Pollution – Components D. D.Other Chemicals and Minerals 1. 1.Acids and acidifying compounds Many originate in the atmosphere (sulfuric acid, nitric acid) or from runoff passing through mine tailings Aquatic organisms generally intolerant of low pH Effects 1) 1)Irritates gills of fishes and crustaceans and interferes with gas exchange 2) 2)Irritates slime layer of fishes (reduces resistance to pathogens) 3) 3)Erodes shells of aquatic mollusks and arthropods 4) 4)Impedes ability of crustaceans to recalcify after molting 5) 5)Facilitates release of toxins bound to particles in sediments

I. I.Water Pollution – Components D. D.Other Chemicals and Minerals 1. 1.Acids and acidifying compounds Many originate in the atmosphere (sulfuric acid, nitric acid) or from runoff passing through mine tailings Aquatic organisms generally intolerant of low pH Effects 1) 1)Irritates gills of fishes and crustaceans and interferes with gas exchange 2) 2)Irritates slime layer of fishes (reduces resistance to pathogens) 3) 3)Erodes shells of aquatic mollusks and arthropods 4) 4)Impedes ability of crustaceans to recalcify after molting 5) 5)Facilitates release of toxins bound to particles in sediments

I. I.Water Pollution – Components D. D.Other Chemicals and Minerals 2. 2.Nutrients Nitrates, nitrites, phosphates Common sources 1) 1)Crop and lawn fertilizers 2) 2)Manure 3) 3)Sewage 4) 4)Detergents containing phosphates and nitrates Excessive nutrient loading  eutrophication Effects 1) 1)Plant growth can clog waterways (ecology, navigation) 2) 2)Plants can interfere with recreation (swimming, boating) 3) 3)Algal growth can impede submerged plant growth 4) 4)Nighttime oxygen depletion 5) 5)Nitrate  methemoglobinemia (blue baby syndrome) Nutrients can be difficult to control once in a system Recycling and regeneration Eutrophied water bodies can recover if sources are removed Ex: Lake Washington

Kiely 1997 Environmental Engineering

I. I.Water Pollution – Components D. D.Other Chemicals and Minerals 3. 3.Metals Normal constituents of fresh waters at low concentrations Human activities sometimes lead to elevated levels May not be toxic at low concentrations or low trophic levels Toxic at higher concentrations May bioaccumulate and biomagnify Effects 1) 1)Health – Ex: Aluminum interferes with salt regulation in fishes and causes gills to produce large quantities of mucus 2) 2)Chelators – Bind nutrients, trace elements, and other necessary chemicals

I. I.Water Pollution – Components E. E.Sediments (Siltation) Suspended particles, usually from erosion in watershed Especially problematic in areas with Plowed fields Construction sites Logging sites Strip-mined areas Effects 1) 1)Clog respiratory/feeding structures 2) 2)Abrade skin and shells 3) 3)Smother eggs and larvae on bottom 4) 4)Impair photosynthesis by blocking light 5) 5)Transport bound chemicals 6) 6)Decrease aesthetic, recreational, commercial value (beneficial uses) 7) 7)Fill in crevices and, eventually, water bodies

I. I.Water Pollution – Components F. F.Heat (Thermal pollution) Sources Condenser cooling water from electricity generating facilities (industrialized nations) Especially problematic in areas with low flow rates Heat discharged per kW generated has dropped by 50-70% since 1950 Generation capacity has increased substantially Total heat discharge today % greater than in 1950 Effects 1) 1)Reduces solubility of O 2 2) 2)Increases rate of degradation (exacerbates O 2 depletion) 3) 3)Disrupts life cycles of organisms that use temperature changes as cues 4) 4)Enhances development of some eggs/larvae/juveniles and inhibits/kills others 5) 5)Alters composition of algal community - Diatoms dominate cool, oligotrophic waters - Chlorophytes dominate warm, oligotrophic waters - Cyanobacteria dominate still warmer waters

II. II.Biodiversity – Definitions and Assessment Major issue – Potential loss as a result of human activities A. A.Definitions Discussion requires clear consensus about what biodiversity is and how it’s defined Fundamental unit = species What is a species?? 1. 1.Species Group of genetically similar organisms that interbreed naturally and freely to produce viable, fertile offspring, but do not share this behavior and outcome with individuals of other species Problem: Some people consider this definition to be inadequate. Why??

II. II.Biodiversity – Definitions and Assessment A. A.Definitions 1. 1.Species a. a.Geographic Isolation Populations could interbreed if geographic barrier could be surmounted Separate species? Subspecies? Populations? b. b.Natural Hybrids Ex – Horse + Donkey  Mule Ex – Queen + Blue  Townsend’s Angelfish Separate species? If a natural hybrid disappears, is it really gone so long as parent species remain? c. c.Polymorphism Ex - Hamlets How different must two species be to constitute separate species? Humans and chimpanzees are estimated to be 98% identical at the DNA level.

II. II.Biodiversity – Definitions and Assessment A. A.Definitions 1. 1.Species a. a.Geographic Isolation Populations could interbreed if geographic barrier could be surmounted Separate species? Subspecies? Populations? b. b.Natural Hybrids Ex – Horse + Donkey  Mule Ex – Queen + Blue  Townsend’s Angelfish Separate species? If a natural hybrid disappears, is it really gone so long as parent species remain? c. c.Polymorphism Ex - Hamlets How different must two species be to constitute separate species? Humans and chimpanzees are estimated to be 98% identical at the DNA level.

BlueQueen Townsend’s

II. II.Biodiversity – Definitions and Assessment A. A.Definitions 1. 1.Species a. a.Geographic Isolation Populations could interbreed if geographic barrier could be surmounted Separate species? Subspecies? Populations? b. b.Natural Hybrids Ex – Horse + Donkey  Mule Ex – Queen + Blue  Townsend’s Angelfish Separate species? If a natural hybrid disappears, is it really gone so long as parent species remain? Quagga c. c.Polymorphism and Genetic Variability Ex - Hamlets How different must two species be to constitute separate species?

BarredBlack Blue Golden Indigo Yellowtail

II. II.Biodiversity – Definitions and Assessment A. A.Definitions 1. 1.Species How do we identify a species? How do we quantify the number of species in an area when there is disagreement about what constitutes a species? Recently: Focus on preservation of processes that lead to speciation Suggests emphasis on conservation of intact habitat vs. single species (HCP vs. ESA)HCPESA