ess water topic 4

ess water

water budget

quantitative estimate of the amounts of water in stores and flows of the water cycle

water distribution across sources

96% in ocean, then glaciers/ice caps + groundwater, then surface water

turnover time

the time it takes for a molecule of water to enter and leave a particular part of the system before it is known as turnover time, and varies (e.g. oceans — 37,000 years, rivers — 12-20 days)

(non)renewable water

water is either renewable or non renewable, depending on where it is stored. extract water from sources at the rate it's being refilled = sustainable

hydrosphere

total amount of water on earth

drivers of hydrological cycle

solar radiation and gravity

hydrological cycle

water constantly moves through different phases in the hydrosphere

surface run off

water that stays on top of the land and flows back to a water source.

infiltration and percolation

water on the ground surface enters the soil

groundwater

water that fills the cracks and spaces in underground soil and rock layers

transpiration

evaporation of water from the leaves of a plant

precipitation

any form of water that falls from clouds and reaches Earth's surface

evaporation

the process by which water changes from liquid form to an atmospheric gas

dissolved oxygen

water dissolved between water molecules which is available for fish breathing

water security

having access to sufficient amounts of safe drinking water

water scarcity

refers to the limited availability of water to human societies

economic water scarcity

occurs when there is enough water available, but financial, institutional, or infrastructural barriers prevent people from accessing it

physical water scarcity

occurs when there is not enough water available to meet demands of population

dams and reservoirs

large infrastructure projects designed to store water by controlling the flow of rivers. by trapping water during wet seasons, they can ensure a reliable supply during dry periods, reducing the risk of water shortages

rainwater catchment systems

involves collecting and storing rainwater from roofs, roads, or specially designed catchment areas for later use

desalination plants

the process of removing salt water and other minerals from seawater to produce freshwater

thermal desalination

seawater heated until it evaporates, leaving salt behind

reverse osmosis

pushing seawater through a semi permeable membrane which allows water molecules to pass through while blocking larger salt molecules

enhancing natural wetlands

wetlands have crucial roles in regulating water supplies: act as natural filters (remove pollutants), store water, reduce risk of flooding and droughts. enhancing them involves protecting existing wetlands or restoring degraded wetlands

water metering

involves installation of meters to monitor the volume of water used in a household

water rationing

used to limit water usage during times of drought or water scarcity. may involve quotas for daily or monthly use or restricting water for specific activities (e.g. turning off hose usage)

grey water recycling

use of water from household activities such as washing dishes, bathing, or laundry for non potable purposes

low flush toilets

low flush/dual toilets designed to use less water per flush compared to conventional

greenhouses using recycled rainwater

greenhouses equipped with rainwater harvesting systems that collect water from roof and store in tanks - this water then used for irrigating crops inside the greenhouse

aquaponics systems

an integrated farming system that combines aquaculture (raising fish) with hydroponics (growing plants without soil) in a closed loop system. water from fishtanks -> grow beds

drip irrigation systems

method of delivering water directly to roots of plants through network of pipes and emitters (releases droplets directly onto the soil at base of each plant)

drought resistant crops

genetically modified or selectively bred crops to survive with less water; makes them ideal for regions experiencing water scarcity

phytoplankton

producers that form base of aquatic food chains as they are capable of photosynthesis

macrophytes

large aquatic plants visible to the naked eye

overexploitation

the excessive harvesting of a species at a rate faster than it can reproduce and recover

bottom trawling

large heavy nets dragged along seafloor to catch species like cod, shrimp, flatfish, gets a lot of bycatch, damages seafloor

ghost fishing

occurs when lost or discarded fishing gear (e.g. nets, traps, lines) continues to capture marine life

blast fishing

fishing that uses dynamite or other explosives to kill/stun fish and make them easier to collect

poison fishing

some fishers use chemicals such as cyanide to stun fish and make them easier to capture (esp. in tropical fish trade - collecting them for pets)

maximum sustainable yield (MSY) in fisheries

largest long term average catch/harvest that can be taken from a fish stock under prevailing environmental conditions without depleting the population

quota

limit on number of fish that people can fish in a specific time period

marine protected areas (MPAs)

a designated region of the ocean where human activities (e.g. fishing) are either restricted or 100% prohibited

ocean acidification

when CO2 dissolves in seawater, it reacts with water to form carbonic acid, which lowers ocean pH - impacts marine life (particularly organisms relying on calcium carbonate to form shells and skeletons (e.g. corals, mollusks)

coral bleaching

a phenomenon in which algae inside corals die, causing the corals to turn white

aquaculture

farming of aquatic organisms such as fish, molluscs, crustaceans, and aquatic plants in controlled environments including ponds, tanks, and coastal areas

capture fisheries

harvesting of wild aquatic organisms directly from natural bodies of water

open aquaculture systems

aquaculture systems directly connected to natural water bodies, with continuous exchange with surrounding environment

closed aquaculture systems

aquaculture systems that use partially controlled environments, often with barriers or tanks that limit direct exchange with environment

integrated multi trophic aquaculture (MTA)

cultivating multiple species at different trophic levels in same aquaculture environment (mimics natural ecosystems)

recirculating aquatic systems (RAS)

closed loop aquaculture systems where water continuously filtered and recirculated, reduce water usage and prevent pollution from reaching natural water bodies

point source pollution

pollution that originates from a single, identifiable source

water pollution

the contamination of bodies of water by pollutants, either directly or indirectly, and can come from a range of different sources

non-point source pollution

pollution that comes from multiple, diffuse sources

ocean gyres

large ocean circulatory movements caused by winds and coriolis effect that trap plastic waste, e.g. great pacific garbage patch

microplastics

defined as plastic particles less than 5mm in size, produced internationally or from breakdown of larger plastic items

water quality

the condition of water based on a set of chemical, physical, and biological parameters

direct measurements of water quality

ph, temperature, dissolved oxygen, turbidity, nitrate + metal + phosphate concentrations

turbidity

a measure of water clarity or how much light can penetrate through the water

biochemical oxygen demand (BOD)

a measure of the amount of dissolved oxygen required by microorganisms to decompose organic material in water - a high value indicates a large presence of organic pollutants that can negatively affect water quality

total suspended solids (tss)

the total amount of suspended particles, including sediments, organic matter, and pollutants in the water

eutrophication

a process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae