Water and its importance

why water is important to humans, fauna and flora. ELSS

what is flora

plants

what is fauna

animals

why is water important to humans on a cellular scale?

• medium for all biochemical reactions

• each human cell = 70-80% water

• water molecules are polar, allowing them to dissolve ions + organic molecules for respiration, metabolism + waste removal

• blood plasma = 90% water → transports oxygen, nutrients, hormones + waste products

• helps maintain stable body temperature → enzyme activity + overall health

why is water important to humans on a local/global scale?

• vital for crop irrigation, livestock + food processing

• agriculture = 70% of all freshwater withdrawals

• e.g Indus River Basin supports 300M people in Pakistan + India → irrigation for wheat, rice + cotton

• temporal scale → water demand fluctuates seasonally

• droughts/heavy rain = crop failure, food insecurity (East African 2011 drought)

why is water important to humans on a regional/global scale?

• essential for manufacturing, energy productions + cooling

• industries use water for cleaning, processing + as a solvent

• e.g 1tonne of steel = 300k l of water

• Rhine River (Europe) supports industrial zones → supply water for factories + power plants

• temporal → water usage increased due to econ development.

• water scarcity = disrupt production + econ growth (e.g 2018 European heatwave → reduced river flow, halted shipping, etc.)

why is water important to flora on a cellular scale?

• reactant in photosynthesis (plant convert sunlight + co2 + h2o = glucose + o2)

• this reaction is the foundation of nearly all food webs + gives oxygen that supports aerobic life

• plant cell = 80-90% water by volume → fills central vacuole, creates turgor pressure that maintains cell structure + drives growth

why is water important to flora on a spatial scale?

• water availability determines distribution + productivity of global biomes

• tropical rainforests: amazon basin, >2000mm rain/year = support highest plant diversity on earth → 16,000 tree species, stores 100B tonnes of carbon

• temperate forests: european deciduous forests, 700-1500mm rain/year → supports broadleaf + coniferous trees

• grasslands: n.american prairies, 500-900mm rain/year → dominated by grass, few trees

• deserts: sahara, <250mm rain/year → supports drought-adapted plants e.g cacti + acacias

why is water important to flora on a temporal scale?

• seasonal rainfall patterns (e.g monsoon in S.Asia) drive plant growth, flowering + seed dispersal

• over millennia, shifts in climate + water availability = forest expansion/contraction e.g sahara transition from savannah to desert ~5000 years ago

why is water important to fauna on a cellular scale?

• needed for physiological processes e.g digestion, circulation, excretion + temp regulation

• animal bodies = 60-80% water by mass (e.g frogs rely on moist skin for gas exchange + hydration)

• hydration + survival → african elephants drink ~200l/day, may travel 50km to find water during dry periods

• camels survive weeks without water → store in their bodies + minimise loss

why is water important to fauna for habitats and biodiversity?

• aquatic ecosystems: rivers, lakes, oceans → home to vast diverse animal life. amazon river → 3000 fish species (e.g amazon river dolphin + otter) covers 6% of earth’s land surface. most productive habitats

• terrestrial ecosystems: availability shapes distribution + abundance → serengeti, 1.5M wildebeest migrate annually following seasonal rains → amphibians breed in temp ponds

why is water important to fauna on a spatial and temporal scale?

• spatial: influence ranges from microhabitats to continental migration

• temporal: dependence on water can be daily, seasonal (e.g breeding, migration) or evolutionary. droughts/floods can cause rapid changes in populations + migration patterns → evolutionary adaptation occurs over thousands of years