Cycles of Matter 3-3

Energy and matter move through the biosphere very differently Energy has a 1 way flow Matter can be recycled within & between ecosystems

Elements, chemical compounds, & other forms of matter are passed from 1 organism to another, & from 1 part of the biosphere to another, through the biogeochemical cycles Biogeochemical cycles connect biological, geological, chemical aspects of the biosphere

Water Cycle Water moves between land, atmosphere, and the oceans The water cycle consists of evaporation & transpiration, condensation, & then precipitation

Evaporation – water enters atmosphere from ocean, lakes, & puddles Transpiration – water enters atmosphere from plant leaves Condensation – water vapor cools and forms clouds, that hold moisture

Precipitation – moisture droplets in clouds become too heavy, and fall back to Earth Water on land runs along surface until it meets a body of water – runoff Water also enters soil to replenish ground water levels - seepage

Nutrient Cycles Nutrients – all chemical substances an organism need to survive –Chemical building blocks Plants get nutrients from environment Like water, nutrients are passed between organisms and environment

Carbon Cycle Key ingredient in living tissues Found in skeletons & rocks as CaCO 3 Found as CO 2 in atmosphere –Taken in by plants during photosynthesis, given off by plants and animals

4 main types of processes that move carbon through its cycle 1)Biological processes – photosynthesis, respiration, decomposition 1)Take up & release carbon 2)Geochemical – erosion & volcanic activity 1)Release CO 2 to atmosphere &oceans

3) Mixed biogeochemical processes – burial & decomposition of dead organisms & conversion under pressure into coal & petroleum 1) Stores carbon 4)Human activities – mining, cutting & burning trees, burning fossil fuels 1) release CO 2

Nitrogen Cycle All organisms require nitrogen to make amino acids (proteins) Nitrogen gas makes up 78% of the atmosphere Ammonia (NH 3 ), nitrates (NO 3 -), & nitrites (NO 2 -) are found in animal wastes & dead/decaying organic matter

Nitrogen exists in oceans & other large bodies of water Humans add nitrogen to the biosphere (nitrates) when they use fertilizer

Nitrogen in the Biosphere Nitrogen fixing bacteria convert N 2 gas to ammonia (NH 3 ) The bacteria live in soil & on roots of plants called legumes This conversion happens in a process called nitrogen fixation

Other bacteria in soil convert ammonia to nitrates & nitrites Once NO 3 - and NO 2 - are available, producers use them to make proteins Consumers eat producers and reuse N 2 to make their own protein

When organisms die, decomposers return nitrogen to the soil as ammonia Other soil bacteria convert nitrates into nitrogen gas –Known as denitrification –Releases nitrogen into the atmosphere again

Phosphorus Cycle Phosphorus is important to organisms because it forms part of DNA & RNA Rare in the biosphere Does not enter atmosphere

Found on land in rocks and soil minerals, and in ocean sediments Exists as inorganic phosphate

As rocks and sediments wear down, phosphate is released Washed into rivers from land - used by marine organisms On land, phosphorus cycles between organisms and soil

Producers uptake phosphate from soil or water Phosphate is then bound to organic compounds Compounds move to consumers & then rest of ecosystem

Nutrient Limitation Primary productivity of an ecosystem is the rate at which organic matter is created by producers Controlled by nutrient availability If important nutrient is in short supply – limiting nutrient

Limiting nutrient – single substance that limits an ecosystem’s productivity Reasons for fertilizer –Contain N:P:K -> helps plants grow larger & more quickly

Open oceans are considered nutrient poor –Contain only 1/10,000 amount of N 2 as soils –Nitrogen is limiting agent in salt water –Sometimes it can be silica or iron

In freshwater – phosphorus is limiting nutrient When an ecosystem receives a large amount of limiting nutrient it results in an algal bloom Algal bloom – increase in algae & other producers

Why? – more nutrients available –Producers can grow & reproduce more quickly –Without consumers, algae can cover surface of water When all nutrients are used up, algae die –Fed on by bacteria –Cause water to become stinky