C7 Human Dependence + Impact on Ecosystems

benefits supplied to humans by ecosystems, whether they be natural or man-made

benefits supplied to humans by ecosystems, whether they be natural or man-made - Provisioning: products/resources obtained (wood, metals, wool, medicinal products) - Regulating: benefits supplied by ecosystem regulation (pollination, erosion/flood control, climate regulation) - Cultural services: non-material benefits (bushwalking, boating, religious activities, enjoyment) - SUPPORTING SERVICES: overarching, necessary for entire ecosystem function (nutrient cycles, water cycle, Phs)

• there is a clash between short term individual benefits, and long term ecosystem/societal benefits due to: undervaluing of ecosystem services, overvaluing of material products • there is rapid, unsustainable human growth due to an increasing pop size and a larger per person consumption rate • a lack of awareness leads to: decrease in biodiversity, alteration of ecosystems • often human-caused disruptions are hard to reverse

RENEWABLE - naturally replenish over time and can keep up with the rate of human consumption - wood, wind, solar energy, water NON-RENEWABLE - do not renew themselves rapidly enough to keep up with the rate of human consumption - coal, oil, gas, nuclear energy

• is a measure of the total ecological area that is required to sustain a person/population • how much productive land/water something requires in order to produce all the resources it consumes, and absorb all the waste it generates • measured in GHA (global hectares)

• the capacity of an ecosystem to regenerate everything we use/demand from that area • a measure of how much an area can sustainably provide to society • 6 demand categories: cropland, fishing grounds, carbon, grazing land, forest products, built-up land (cities)

deficit/reserve are the difference between biocapacity and ecological footprint. (take one away from the other) DEFICIT - a regions ecological footprint is higher than its biocapacity - the region is using more than is sustainably available to them RESERVE - a regions biocapacity is higher than its ecological footprint - the region is using less than what is sustainably available to them

• resource intensity in production of goods/services (how much is needed to produce something) • consumption of goods/services per person • population size

• countries with higher GDP have larger ecological footprint per person • they can afford more, and therefore consume more per person (buy more food/goods, live in larger houses, use more energy, use more water)

POLLUTION - always human caused - a substance introduced into an environment causes harm CONTAMINATION - not always human caused - there are higher lvls of a substance than usual - doesn’t have to cause harm • there can be contamination w/o pollution, but for pollution to occur, contamination has also occurred.

SOURCES - human (deliberate or accidental) - natural (volcanic ash, faeces) FORMS - organic (e.g. animal waste) - inorganic (e.g heavy metals) • organisms (invasive) • nutrients (e.g. fertiliser) • energy (light, heat, sound) IMPACTS - death to organisms - decreased health (humans, organisms, ecosystems) - reduced quality: soil, air, water

POINT VS NON-POINT - Point: one single location that pollution is coming from, easier to identify and control (e.g. pipe) - Non-point: multiple, dispersed source of pollution, harder to identify and manage (e.g. city air pollution) PRIMARY VS SECONDARY - Primary: active/harmful on emission (plastic, CO2, fertilisers) - Secondary: not necessarily harmful on emission, must react to cause harm (formation of acid rain and photochemical smog) PERSISTENT VS DEGRADABLE - Persistent: cannot be decomposed, leads to build-up of pollutant, is passed along food chains, majorly affects high trophic lvls (heavy metals, DDT) - Degradable: can be decomposed by enzymes or bacteria, does not lead to build up/passed along food chains (modern pesticides, bioplastics)

when water becomes enriched with nutrients due to runoff of artificial fertilisers used in farming (nitrates/phosphates) PROCESS/CAUSES - excess nutrients causes algal blooms - algae block out the sunlight for plants underneath: without Phs, they die - death of plants + the algae creates thick layer of dead biomass on bottom of waterway - biomass must be decomposed by large amounts of bacteria, which through CR, use up all the dissolved O2 in the water - without access to plants or oxygen, fish deaths

BIOACCUMULATION - the buildup of persistent chemicals within an organism, due to ingestion/absorption of a toxin - most affects organisms with a longer lifespan, which have a longer time to accumulate the toxin (higher trophic lvls) - poisoning occurs once toxin lvl gets too high BIOMAGNIFICATION - the buildup of persistent chemicals within a food chain, leading to higher concentrations within higher trophic lvls Most affects high trophic levels: - as the organism size increases, it must eat larger quantities of food to survive (due to trophic energy loss) - leads to magnification of the pollutant due to a higher pollutant conc - tuna, swordfish, shark etc

• pH • nitrates/ammonia • dissolved O2 • conductivity (ability to pass electric currents could indicate heavy metals) • turbidity (how clear) • faecal coliform tests (bacteria from animal guts)

• gets into water via: diffusion from atmosphere, movement of water, Phs by autotrophs • it is often reduced in the presence of pollutants due to many decomposing bacteria (eutrophication) Can be measured indirectly through BOD - biochemical oxygen demand - the amount of O2 consumed by bacteria + other organisms when breaking down organic matter - when pollution occurs, more bacteria are required to break down the dead matter, increasing respiration, increasing the demand for O2 INCREASE IN POLLUTANTS = INCREASE IN BOD = DECREASE IN DISSOLVED O2

INDICATOR SPECIES/BIOTIC INDEX - species that are very sensitive to environmental conditions - absence/presence/abundance of these will suggest the level of an ecosystem’s health - the absence of several indicators of similar tolerance lvls may equal pollution

• global production of fish/seafood has quadrupled in the last 50 years in order to feed the growing population • wild harvest is fish that are taken from the sea (pots, nets, trawling, dredging, traps, longline)

• when fish are being caught faster than the population can naturally replenish itself: too many adult fish are being caught to repopulate • this significantly depletes populations = extinction (most threatens sharks/rays) • population growth will continue to increase the amount of fish caught • without change, overfishing will destroy ecosystems, biodiversity and ocean health beyond repair

Many methods of fishing destroy habitat. DREDGING - metal scoop to harvest clams etc is dragged along the sea floor - churns up sediment crushes coral/habitat - digs up burrowing animals - decreases water quality SEAFLOOR TRAWLING - nets pulled across to collect bottom-dwelling fish - destroys coral/oysters/sponges (habitat) - destroys filter feeders (vital for preventing eutroph by eating nutrients) - depletes benthic fish pop.s (vital for nutrient cycles) BLAST FISHING - dynamite thrown into water, causes fish to float to surface for easy capture - massively destroying species/habitat

Ghost fishing gear = gear that has been lost/abandones in the ocean PLASTIC - majority of ropes/nets are made of plastic - lasts for centuries - releases microplastics, eaten by organisms (cause internal harm + release chemicals) ENTANGLEMENT - captures targeted species: fishers have to compete with lost gear (e.g. pots/nets) - captures non-targeted species (bycatch) - injures organisms, or prevents from moving or coming up for air CORAL REEF DESTRUCTION - broken corals from ghost gear makes them vulnerable to disease - nets block out light, preventing Phs

• are non-targeted species • cannot always be released back, or may be injured • removes species from sea that are vital to biodiversity/ecosystem • has negative flow-on effects due to relationships between species LONGLINE FISHING - birds attracted to bait - turtles get bait lodged in mouth and drown - mammals become trapped in line TRAWLING - collects unwanted animals in nets

• better hooks/lines that target species and reduce bycatch • ‘pingers’ on ships deter marine animals from the area • bycatch reduction devices on pots • different methods of collection (e.g. individual oyster harvesting instead of dredging) • possibly aquaculture (fish farms)

PROS - large fish yield: feeds a growing population - theoretical decrease in wild fishing: allowing pop.s to replenish - recycles waste from fishmeal/livestock to feed fish CONS - mainly, large carnivorous fish are being farmed: means more fish must be caught in wild harvest to feed fish in farms - habitat destruction: to make room for farms - escape of non-native species: cross-breeding with local fish causes genetic modification, brings pathogens into ecosystems - waste produced: uneaten fish food and faeces causes eutroph + smothers seafloor, -hormones/chemicals used on fish cause bioaccumulation + bacteria resistance, pathogens/parasites are released from overstocking pens