Environmental chem test 2

Exergonic vs endergonic

Exergonic- releases energy (cellular respiration, wildfire, rusting), spontaneous

Endergonic- absorbs energy (photosynthesis, charging battery) non-spontaneous

• producers use solar energy for endergonic rxn and consumers harvest energy via exergonic

Carbon cycle

• photosynthesis

• aerobic respiration

• combustion

• ocean CO2 dissolution: CO2+H20 → H2CO3 → H+ + HCO3 → H2 + CO3^2-

• Silicate weathering- CaSiO3 +CO2 → CaCO3 +SiO2 (removes Co2 over millions of years)

Nitrogen cycle

same just review

Ocean acidification

Post industrialization has caused a pH of 8.2 to 8.1 which is a 26% increase in acidity (7.8 in 2100)

• CO2 + H2O → H2CO3 (carbonic acid)

• H2CO3 → H+ + HCO3^- (bicarbonate)

• HCO3 - → H+ + CO3 2- (carbonate- what shells are made of)

excess H+ ions react with CO3 2- and effect the forming of shells

Ocean acidification impacts

• Pacific oyster impact

  • Larval shells were dissolving faster than they form (2007-2008)

• Coral bleaching

  • Co3 2- depletion + warming → corals expel zooxanthellae (symbiotic algae) → bleaching

  • great barrier reef has had 4 mass bleaching events in 7 years

Lake Stratification

• thermocline= temp gradient

• halocline= salinity gradient

• Pycnocline= density gradient

Epilimnion (warm and oxygenated)

Thermocline (rapid T drop, mixing area)

Hypolimnion (cold, dense, low O2)

Bio accumulation

build up of a substance within a single organism over its lifetime

Biomagnification

increase in concentration across trophic levels

Kow

high- lipophilic (prefers fats) bioaccumulates and biomagnifies
low- hydrophilic (stays in water) excreted easily

Biodiversity

alpha diversity- diversity within a single habitat
Beta diversity- turnover between habitats
Gamma diversity- total regional diversity (alpha + beta)
Shannon diversity index H’=-sum(pi x ln pi)- accounts for richness and evenness

• higher values= more diverse community

Water properties

high specific heat capacity
high latent heat of vap
max density at 4 degrees Celsius
universal solvent

hydrogen bonding

high surface tension

Water treatment process

• coagulation- alum dissociates in water into Al 3+ ions and neutralizes negative charges in clay particles and particles clump

• Flocculation/sediments- floc settles to bottom removes turbidity

• Filtration- water moves through sand and removes fine particles and microbes

• Disinfection (Cl2/UV)- chlorine kills pathogens via oxidation

HIPPO (HIPPCO)

Habitat loss

Invasive species

pollution

population (overexplotation)

climate change

Ecosystem energy flow

top

• hypothetical apex 10 kcal/m2/yr

• lions (carnivores) 100

• Wildbeest (herbivores) 1000

• Grasses (producers)- 10,000

90% energy lost as heat in each step

GPP formula

total photosynthesis

NPP

NPP=GPP-plant respiration (Ra)

energy available to all other organisms in the ecosystem

Trophic cascade- sea otters

• sea otters removed from fur trade

• sea urchins explode- without otter predation urchins grow

• kelp forests collapse- urchin barren replace dens kelp and eliminates habitat

• Fish and wildlife decline- rockfish, harbor seals, bald eagles, all decline and ecosystem collapses

• otter recovery- full ecosystem recovery