Global change

Pollution

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

Some pollutants are metabolized or excreted, others accumulate in tissues

Bioaccumulation

Occurs when pollutants(toxins) are stored in tissues(usually fat) instead of excreted

Can cause trophic collapse

Impacts long lived organisms the most

Biomagnification

Occurs when bioaccumulated pollutants become concentrated in higher trophic levels

Top consumers most severely affected

Chemical pollution

Spreads far from source to have widespread impacts

Often endocrine disruptors

Enters ecosystems through industrial waste, agriculture, sewage, consumer products & combustion

endocrine disruptors

Chemicals that disrupt normal hormone functions

Acids rain

Combustion releases sulfur & nitrogen oxides that react with water in air to make acids

Typically =<4-5 exceeding biological limits

Ozone layer thinning

Thinning because of ozone-destroying pollutants

plastic pollution

Synthetic compounds typically made from petroleum products

Ocean currents trap litter including plastic pollution, in large stationary whirlpools(gyres)

Can persist for 100s of years

Animals eat and get entangled in it

Can carry bacteria

Environmental pollution

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

Nutrient enrichment

Nutrients(mainly nitrogen & phosphorus) leach into aquatic systems and overload primary producers

Nutrient pollution

Comes from industrial pollution, sewage, agriculture, and crop fertilizers

Agricultural practices affect nutrient content in soil

Crop harvesting removes nutrients, fertilizers add nutrients but excess remain

Critical load

Maximum amount of nutrients that primary producers can absorb

Eutrophication

Nutrients > critical load

Leads to explosive plant growth

Leads to algal blooms and dead zones

Dead zones

Decomposition of excessive plant matter creates hypoxic(oxygen depleted) water that kills wildlife

Algal blooms

an explosion of algae in water that causes the loss of oxygen in the water

Can also produce deadly levels of toxins that threaten human and wildlife health

Harmful algal blooms(HABs)

Produce toxins that kill wildlife

Toxins bioaccumulate in marine mammals and birds

climate change

CO2 rapidly rising in last 200 years

Air bubbles in glacial ice provide a longer record

Amount of warming

1.1 degrees C increase over 100 years

10% decrease in snow and ice extent

Greenhouse gases

Reflect heat that would otherwise escape to space back toward earth

Increased concentrations of greenhouse gases has caused earth to warm

Human activities have increased multiple greenhouse gases: methane, nitrous oxide, carbon dioxide

CO2 Rise

Atmospheric CO2 concentration has been increasing because of human activity

Can tell from fossil air in ice cores

Carbon isotope evidence

CO2 sources have different amounts of carbon isotopes

-plants(more C12)

-volcanic eruptions(more C13)

-Young organic matter(more C14)

Young plants have more carbon 13 or 14 which then slowly decay

CO2 is high in C12 with no 14 so it comes from old organic material(aka fossil fuels)

Effects of climate change

Hotter temperatures, more severe storms, warming rising ocean, increased drought

Climate change impacts

Snow, glacier, and ice loss, desertification, ocean warming acidification and sea level rise, drought and wildfire, increased precipitation and severity+frequency of extreme events

Impacts of climate change are interconnected

Ocean impact

Absorbing large amounts of CO2 and heat causing it to warm, acidification

Ice me,t leaves to large sea level rise

ocean acidification

CO2 diffuses into water to produce carbonic acid and lower pH

Impacts calcification of marine organisms

Larger storms

Warmer air hold more moisture resulting in more intense precipitation and storms

Droughts

Higher temperatures increase evaporation making dry regions drier

Precipitation

Net precipitation is increasing

But certain areas are experiencing less precipitation

Wildfires

Prolonged droughts and dry conditions make perfect conditions for wildlfires

Npp disruption

Overall decrease in global NPP -> global shift from carbon sink to carbon source

Increasing in some regions but gains are offset by decreases in other regions

Cellular Impact

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

Higher temperatures increase metabolic rate:

Ectotherms grow more rapidly and consume more food

Organism impact

Rising ten push organisms of physiological limits -> behavioral change and increased mortality

Population impact

Size and phenology altered by temperature and food availability

Migration patterns altered by temperature changes

Phenology

the timing of growth and reproductive activity within a year

Communities

Migratory changes can lead to mismatch (creatures who don't migrate based on temperature arrive to already depleted resources)

Ecosystem

Changes in temperature and precipitation impact fundamental niche space

Species expand or contract ranges or move to new locations, to track climate

Range shift

General range shifts poleward(higher latitude) and upward

Can disrupt trophic interactions

Climate change: future

Models predict future under different scenarios of CO2 emissions:

Higher temperature and more precipitation

4 degrees C higher has extremely serious impact

Predicted by 2100

Gotta stay below 2 degrees C

tipping points in climate change

Could start feedback chains of cascading, accelerating, and irreversible ecosystem change

Disease impact

Disease carriers that live in the tropics will be able to travel further and further north