ai version ocng 412 - exam 2

Megafauna

Animals with a body mass greater than 44kg.

Overkill hypothesis

Extinction results when human hunting causes death rates to exceed birth rates in prey species.

Habitat loss hypotheses (HLH)

As climate changed, areas with adequate conditions to maintain megafauna either disappeared or became too small/fragmented to support populations.

Mosaic-nutrient hypothesis (MNH)

Climate change reduced growing season and plant diversity, and increased plant defenses, reducing herbivore carrying capacity and leading to exchange.

Shifting baselines

Affects our perception of what is natural, what we should try to conserve, how we should restore degraded ecosystems, and the value of different ecosystems.

Decline in the state of the natural environment

Shifting baseline syndrome.

Causes of shifting baseline syndrome

Lack of data, loss of interaction, loss of familiarity.

Consequences of shifting baseline syndrome

Increased tolerance for progressive environmental degradation.

Importance of marine fisheries

Significant source of protein for people and certain cultures/countries.

Overfishing

Causes ocean warming, acidification, nutrient pollution in coastal areas.

Global wild fish stocks

In decline.

Aquaculture

Has increased over the years.

Catch Per Unit Effort (CPUE)

Used to assess fish stocks; assumed that when there are fewer fish they must be harder to catch.

Bycatch

Incidental catch of marine organisms that are caught accidentally with target species.

Ecosystem based fishery management

Organized effort to regulate fisheries to maintain a sustainable fishery.

Standing stock

Mass present in an ecosystem at a given time.

Maximum sustainable yield (MSY)

Max fishery biomass that can be removed yearly and still be sustained by fishery ecosystem.

No take areas (NTA)

Large areas of the ocean that are protected from fishing.

Nitrogen and phosphorus

Are out of the safe operating limit of the 9 planetary boundaries.

Nitrogen cycle

Key stages include nitrogen fixation, ammonification, nitrification, assimilation, and denitrification.

Reactive nitrogen

Biologically available nitrogen (proteins, amino acids, nucleic acids, nitrate, nitrite, ammonium).

Excess reactive nitrogen

Can be a pollutant affecting human health and ecosystem services.

N2O

A greenhouse gas with a high Global Warming Potential (GWP - 290).

Tragedy of the commons

It is in everyone's interest to catch as many fish as possible even if it means the eventual collapse of the fishery.

Atlantic cod fishery

There was a complete collapse around the 1990s, and the population has not gone back up ever since.

Biological factors in marine fishing

Marine fishing focuses on upper trophic levels, where energy is lost as we move up trophic levels.

Fishing methods

Include passive fishing (drift nets and longline fishing) and active fishing (purse seine and trawls).

Nitrogen fixing bacteria

Live in the soil or ocean.

Excess nitrogen from fertilizers

Causes nitrous oxide (N2O) emissions.

Hypoxia

When O2 concentration < 2 ___[units???]___.

Stratification

Organic matter (N,P) floats on the surface of the water.

Pleistocene epoch

Started around 2.6 million years ago.

The Big Freeze

A 1,000 year period of cooling around 13,000 years ago.

Medieval Warm Period

Mean temperature of the earth was 0.5 C warmer.

Little Ice Age

Earth became colder due to volcanic activity creating an ash cloud.

Temperature anomaly

The difference between the observed temperature and a long-term average temperature.

Climate normal

An average temperature in the recent 30-year period.

Greenhouse gases

Water vapor is the major greenhouse gas, not affected by human activities.

Global warming potential

Measure of an individual molecule's long-term impact on atmospheric temperature.

Methane (CH4)

Has a global warming potential of 28 - 36.

Nitrous oxide (N2O)

Has a global warming potential of 265 - 298.

CFCs

Have a global warming potential of 1,000 - 10,000.

Natural processes that release carbon dioxide

Include volcanoes, rock weathering, burial and decomposition.

Human processes that release carbon dioxide

Include fossil fuels, vegetation and soils, net land-use change.

Natural processes that release methane

Include freshwaters, wetlands, geological sources.

Human processes that release methane

Include biomass burning, fossil fuels, landfills and waste.

Natural processes that release nitrous oxide

Include bacteria in the oceans and soils.

Human processes that release nitrous oxide

Include biomass and biofuel, agriculture, atmospheric deposition.

Ocean acidification

Pre-industrial pH of the ocean was 8.2.

Global heating

Leads to more intense storms and rising sea levels.

Shared Socioeconomic Pathways (SSP)

Latest generation of climate models considering different economic models.

Cryosphere

Regions governed in ice and snow either throughout the year or seasonally.

Opportunities

Ice-free Arctic Ocean opens up large areas for oil and gas development; shipping can use the Northwest Passage.

Reduced Arctic sea ice cover

Reduced ice albedo effect; edge of the ice further offshore impacting artisanal fishing and hunting; harder for polar bears to access ice to hunt from; enhanced storm erosion of the coast; ocean circulation and heat distribution.

Melting permafrost

Enhanced emission of greenhouse gases as organic matter decays; significant infrastructure impacts as the ground becomes less stable; enhanced coastal erosion causing the relocation of coastal communities; advancing boreal forests.

Warming oceans

Changes in ocean circulation and heat distribution; ecosystem changes; ice shelf loss around Antarctica.

Retreating glaciers

Cause sea level rise; disruption of freshwater supply to major cities; disruption of agriculture; changing ecosystems.

Thwaites glacier

Florida sized glacier in West Antarctica; major contributor to sea level rise.

Isostatic changes in sea level

Local movement of the Earth's crust results in changes in relative sea level as the land has changed height, not the ocean.

Eustatic changes in sea level

Changes in sea level that occur over the whole earth as a result of changes in seawater volume or ocean basin capacity.

Sea level rise

Has been 40 to 60 mm per year; impacts island nations, low lying nations, coastal cities; affects agriculture and large city infrastructure.

Most vulnerable nation

Maldives; they reside in dispersed islands so they have no place to go to when sea level rises.

Representative Concentration Pathway (RCP)

Scenarios used by climate scientists to model future climate change based on different trajectories of greenhouse gas and aerosol emissions.

Thames Barrier

Largest movable flood barrier in the world; protects from flooding caused by global warming.

Global freshwater use

24,000 km3 yr-1; increases with population and affluence.

Blue water

Water used in industries and cities which is abstracted from rivers.

Green water

Water used for agriculture.

Gray water

Recycled water.

Soil

Mixture of organic matter and mineral particles; formed from the weathering of rocks beneath the soil and the addition of organic matter from plants at the surface.

Soil texture

Depends on the size of particles in the soil.

Soil fertility

Depends on nutrient availability, pH, aeration, water content, etc.

Components of soil

Water, minerals, organic matter, air, soil organisms (microbes and fauna).

Anthrosols

Soils modified by human activity.

Salinization

Increasing the salt content of soils; reduction in crop yields and availability of potable water.

Primary salinization

Natural process in arid areas.

Secondary salinization

Driven by human activities.

Aral Sea

Salinity increased 3x in 30 years; has sunk significantly due to diversion of rivers for irrigation.

Inefficient irrigation system

Most water was lost through evaporation or soaked through unlined canals before reaching the sea.

Effects of pollution from agriculture

Causes eutrophication and algal blooms due to fertilizers and pesticides used for cotton.

Eradication of salt

Removal of salt by improved drainage, leaching salt from the soil with freshwater, biotic treatment by growing and harvesting salt accumulating plants, replanting trees.

Conversion of salt

Chemical treatment of soils to convert harmful salts into less harmful salts, e.g., adding gypsum to soils containing alkali carbonates.

Control of salt

Preventing salt accumulation through methods like sprinkler systems, liming canals, and growth of salt tolerant plants.

Soil erosion

Associated with deforestation and farming; soil is carried away by water and/or wind.

Causes of soil erosion

Deforestation, grazing, irrigation, replacement of grassland with shrubland, fire, construction, and urbanization.

Prevention of soil erosion

Methods include terraces, contour plowing, palm frond fences, sand fences, and low/no-till agriculture.

Sustainable development goals

17 goals agreed upon by 195 countries aiming for peace and prosperity for people and the planet.

Famine causes

Not due to lack of food, but due to lack of distribution of food in certain regions due to geopolitical conflicts.

Agricultural revolution

Transition from hunter-gathering to settled farming communities and domestication of plants and animals.

Second agricultural revolution

Innovations in agriculture that increased productivity, fueling population growth and industrialization.

Green revolution

Increase in agricultural productivity in developing countries during the great acceleration through new crop varieties and extensive use of fertilizers.

Arable land efficiency

Decreased over time as higher yields of crops can be produced from the same land area.

Deforestation in the Amazon

The world has lost one-third of its forest since the last ice age, with forests decreasing in Brazil and parts of Southeast Asia.

Global heating effects

Temperature over the Amazon has increased by 1.5C due to climate change, causing the Amazon to dry out.

Illegal logging

More than 50% of timber production is illegal in most countries.

Health effects of global change

Includes heat stroke, reduced economic productivity, diseases from air pollution, and food insecurity.

Wet bulb temperature

A measurement accounting for both heat and humidity; the upper limit for humans is 35C.

Changes in Lyme disease

Range of ticks has expanded with warming, with tick activity dependent on temperature.

Aerosols

Suspended particles or droplets in the atmosphere that can have health consequences.

Primary aerosols

Released directly into the atmosphere from natural sources like wind blown dust and plants.

Secondary aerosols

Formed from chemical reactions of gases in the atmosphere, involving oxidation and photochemical reactions.