Topic 4: Water and Aquatic Food Production Systems and Societies

how much of the earths water is fresh?

2.5%

hydrological cycle

aquifer

a body of permeable rock that can hold water underneath

evapotranspiration

combination of evaporation and transpiration that requires heat from sunlight and biological action of plants

convection

water carried by hot, moist rising air higher up in the atmosphere

advection

wind-driven movement of water horizontally through the atmosphere

sublimation

snow and ice moving directly to atmospheric storage from solid to gas

percolation

movemenet of water through porous rock and sediment

groundwater

storage of water in rocks underground

what is the process of ocean circulation?

convection currents are lead by:

1. cold water is denser than warm, so cooler currents run deeper in the ocean

2. freshwater is less dense than salty so it stays close to the surface

3. surface currents are triggered by prevailing winds

reservoirs

a large natural or artificial lake that stores water

desalination

dissolved mineral salts are removed from water

grey water

household waste water

water budget

measure of ohow much s available in a system per year

advection

microbes are carried in groundwater flow

irrigation

large scale agriucltura watering systems

el nino southern oscillation

chnags in surface temperature of water in central and easter tropical pacific ocean wat

water scarcity

the level of accesability to water to sustain life

phytoplankton

microscopic marine algae

continental shelf

the seabed and subsoil of submarine areas that extend beyond its coastal state

upwelling

deep,cold water rises toward the surface

biorights

compensating poorer people who depend on areas that need protecting as they depend on it for income

maximum sustainable yeild

the maximum amount we can harvest or collect that doesn’t prevent future generatiosn from using it

rights of indigenous people

indigenous people have the right to live on their land and use it’s resources within carrying capacity

aquaculture

commercial farming of sea produce uch as fish

tragedy of the commons

acting in self interest when consuming resources at the extent of others

limiting factors

an abiotic or biotic factos that limits a population size

organic pollutant

toxic chemicals that are harmful to humans and wildlife that has carbon in its structure

inorganic pollutant

pollutants without carbon in its strucutre

Biochemical Oxygen Demand (BOD)

amount of oxygen needed to remove waste from water from aerobic bacteria breaking it down

indicator species

species that tell us how polluted an area (usually a body of water) is

biotic index

measure of the level of pollution based on population sizes in certain habitats

eutrophication

when algae grow excessively due to excess nutrients (usually fertiliser run-off) in a body of wtaer

dead zones

area in bodies of water where oxygen is low

what are the problems with aquaculture?

1. habitat loss - usually requires the conversion of natural habitats, clearing it or modifications cause disruptions to communities

2. pollution - eutrophication the dead zones, additives in feeds can be harmful, use of antifouling agents to prevents barnacles growths leak in to the surrounding natural habitats and harm to members there, leaking antibiotics

3. spread of diseases - close quarters and low genetic diversity increases risk of diseases spreading, if individuals escape then they can give those diseases to wild individuals

4. escaped species - spread of foreign diseases, genetically modified fish breeding with natural species may cause issues

5. ethical issues and biorights - intensive farming usually have low animal welfare and stress on individuals, intrinsic rights debate

6. rights of indigenous cultures - introduction of industrial aquaculture and non-native species may disrupt the native traditions and fishing communities, could push them out of work

7. international conservation agreements - there are agreements to conserve genetic diversity (CBD)

what are the benefits of aquaculture?

1. helps to meet rising demand - instead of over fishing in the oceans, controlled populations for consumption allows for wild numbers to be sustained

2. technological advancements - rising technology help to increase this method’s sustainability

3. natural species can be genetically modified to contain more nutrients

4. governments can address food security

5. from irreversible ecosystem damage, some populations can continue to be farmed using aquaculture

winkler test

to measure the amount of dissolved oxygen in a sample, chemicals are added ass soon as possible to a sealed bottled sample then titrating a reagent into it until it turns to the ‘endpoint colour’ (dark blue). the amount of reagent used is the equivalent to the concentration of dissolved oxygen in the mixture

what can excessive biodegradation of organic materials cause?

1. depleted oxygen levels cause anoxic conditions

2. anaerobic decomposition takes place thern methane, hydrogen sulfide and ammonia are produced

3. methane is a strong greenhouse gas

4. hydrogen sulfide is toxic to marine animals

5. ammonia is also toxic and contributes to nutrient pollution increasing eutrophication