Global Change

pollutant

harmful materials that damage the quality of air, water, & land

Chemical pollution

industrial compounds, pesticides, pharmaceutical; spreads far from source to have widespread impact; enter ecosystems through industrial waste, agriculture, sewage, consumer products, & combustion

endocrine disruptor

chemical pollutants that interrupt normal physiological functions (including in humans)

ex. Chlorinated hydrocarbons (e.g., PCBs, DDT) & inorganic compounds (e.g., mercury)

bioaccumulation

ccurs when pollutants (toxins) are stored in tissues (usually fat) instead of excrete; Organisms at all trophic levels accumulate toxins over their lifetime, with long-lived organisms most impacted; can cause trophic collapse (Silent Spring)

biomagnification

occurs when bioaccumulated pollutants become concentrated in higher trophic levels; Top-level consumers are most severely affected by environmental toxins

acid rain

occurs because of industrial pollution; Combustion releases sulfur & nitrogen oxides that react with water in air to make acid; pH is typically <4-5, exceeding biological limits

ozone depletion

thinning since 1970’s because of ozone-destroying pollutants (e.g., CFCs); worst in south pole because cold air allows ozone-depleting reactions to continue year round; Regulations have stabilized, but pollutants already in atmosphere will continue depleting ozone for 50+ year

Plastics polution

Synthetic compounds typically made from petroleum products; Can persist for 100s of years; Animals eat it & get entangled by it; Can carry bacterial pathogens; Effect of consuming microplastics unknown

gyres

large stationary whirlpools in ocean that trap litter, including plastic pollutio trap litter, including plastic pollution

environmental pollution

Noise and light pollution impact animal communication, behavior, and physiology

Nutrient Enrichment

Nutrients (mainly Nitrogen & Phosphorus) leach into aquatic systems & overload primary producers from industrial pollution, sewage, agriculture, & crop fertilizer

Critical load

the maximum amount of nutrients that primary producers can absorb

Eutrophication

occurs when nutrients > critical load & leads to explosive plant growth

aquatic dead zone

Decomposition of excessive plant matter depletes oxygen; Hypoxic water kills wildlife; caused by algal blooms

ex. Gulf of Mexico

greenhouse gas

reflect heat that would otherwise escape to space back toward Earth

ex. Methane, Nitrous Oxide, Carbon Dioxide

CO2 levels

CO2 in air continuously monitored since 1958 at Mauna Loa, Hawaii & other global locations; Air bubbles in glacial ice provide a longer record

Atmospheric CO2 concentration has been increasing because of human activity

Carbon isotope data

provides definitive evidence that humans are source of CO2 increase

CO2 sources have different

amounts of carbon isotopes:

• Plants: more 12C

• Volcanic eruptions: more 13C

• Young organic matter: more 14C

Atmospheric CO2 has high 12C and low 14C & 13C: the carbon is very old & from organic material… Only fossil fuels meet this criteria

rising temperatures

increased concentrations of greenhouse gases has caused earth to warm; Since 1900, Earth has warmed 1.1ºC (2ºF)

climate change

global warming, more severe storms, rising water levels, increased drought, glacier/ice loss, desertification, wildfires, acidification

interconnected

Ocean acidification

CO2 diffuses into water to produce carbonic acid & lower pH

Climate change disrupting net primary productivity

Overall decrease in global NPP → global shift from carbon sink to source

Cellular effects of climate change

processes like DNA replication, cell division, enzyme activity are all impacted by temperatures

Organism effects of climate change

Rising temperatures push organisms outside of physiological limits → behavioral change & increased mortality

Population effects of climate change

size & phenology (timing of growth & reproduction) altered by temperature & food availability; Higher temperatures increase metabolic rate: ectotherms grow more rapidly & consume more food

Community effects of climate change

Migratory changes can lead to mismatch

Ecosystem effects of climate change

Changes in temperature & precipitation impact fundamental niche space; Species expand or contract ranges, or move to new locations, to track climate; Range shifts can disrupt trophic interactions

range shifts due to cimate change

poleward (higher latitude) & upward in elevation as global temperatures increase; reflect temperature constraints

Climate Change Future

if status quo is kept = 4ºC or more increase by 2100