Chemicals are recycled between organic matter and abiotic reservoirs Chemicals are recycled between organic matter and abiotic reservoirs Nutrients recycle between Organisms and abiotic reservoirs 4 basic steps in cycling 3 Consumers 2 Producers 1 Detritivores Nutrients available to producers 4 Figure 37.15 Abiotic reservoir

Biochemical Cycles Involve both abiotic and biotic components Can be local or global cycles Soil is main reservoir in local cycles (Phosphorus) Air or Gases are reservoirs in global cycles (Carbon, Nitrogen & Water)

Water moves through the biosphere in a global cycle Transport over land Solar energy Net movement of water vapor by wind Runoff and groundwater Percolation through soil Precipitation over land Evaporation and transpiration from land Precipitation over ocean Figure 37.16 Evaporation from ocean Water moves through the biosphere in a global cycle Solar heat Drives the global water cycle of precipitation, evaporation, and transpiration

What does the level of the chemicals we’re testing tell us about the Chaska Creek? We will test: Ammonia Dissolved Oxygen Carbon Dioxide pH Nitrates Phosphates Total Hardness

The carbon cycle depends on photosynthesis and respiration The carbon cycle depends on photosynthesis and respiration Carbon is taken from the atmosphere (CO2)by photosynthesis Used to make organic molecules, and returned to the atmosphere by cellular respiration Carbon compounds in animal waste, plant litter & dead organism is consumed by detritivores and they return the carbon via cellular respiration. CO2 in atmosphere Photosynthesis Cellular respiration Burning of fossil fuels and wood Carbon compounds in water Detritus Primary consumers Higher-level Decomposition Figure 37.17

Why measure Dissolved Oxygen? O2 is essential to life Sources are photosynthesis and air (surface current) The higher the stream flow the more dissolved oxygen Depleted by Decomposition of dead organisms and waste Respiration of plants and animals Lower the temperature the more O2 water can hold. Warm water fish need 02 levels of 4 ppm (parts per million) Cold water fish (trout, walleye) need 02 levels of 5 ppm

Why measure Carbon Dioxide (CO2)? CO2 is needed for photosynthesis Co2 is harmful in high concentrations. Fish must get ride of CO2 and take in O2 Very hard to do is CO2 is in high concentrations CO2 is 200 times more soluble in water as O2 Normally less than 10 ppm in streams

Why measure pH? pH is a measure of acidity (7 is neutral, 1 is the most acidic and 14 is the least acidic “basic”) Problems occur if more acidic than 5 and more “basic” than 8.5) CO2 from cellular respiration and decomposition lowers pH, so polluted water is typically more acidic (because of higher rate of decomposition) You may need to use it determining ammonia levels. (we’ll talk about this later)

The nitrogen cycle relies heavily on bacteria The nitrogen cycle relies heavily on bacteria Various bacteria in soil Convert gaseous N2 to compounds that plants use: ammonium (NH4+) and nitrate (NO3–) Detritivores Decompose organic matter and recycle nitrogen to plants An ingredient of proteins & nucleic acids = important to organisms Atmosphere is 80% Nitrogen, making it a large reservoir Nitrogen in atmosphere (N2) Nitrogen fixation Nitrogen-fixing bacteria in root nodules of legumes Detritivores Decomposition Ammonium (NH4+) Nitrates (NO3–) Assimilation by plants Denitrifying bacteria soil bacteria Nitrifying Figure 37.18

Why measure Nitrates? Nitrates are essential for plant growth High levels are signs of pollution from fertilizer or sewage Too much nitrate = algal blooms = decrease in oxygen levels Nitrate is a limiting factor on plant growth Decreases oxygen because oxygen is used up in the process of decaying all the algal growth and cellular respiration of animals Good levels would be under 1 mg/L High levels can cause “Blue Babies” – umbilical cord around neck

Why measure Ammonia? Ammonia is a major metabolic waste produce from fish Important to test because even small amount can cause stress to fish and damage their gills Two types in water: Total Ammonia (NH4+) – Ionized Ammonia Unionized Ammonia (NH3) – this is toxic to fish Temperature and pH effect how much of this is present Sources of ammonia in waters include: runoff of animal wastes fertilizers from farm land the discharge of sewage effluents dairy shed effluents food-processing wastes such as those from freezing works.

Ammonia Continued… Test kit will measure Total Ammonia (Ionized Ammonia) Ammonia levels should be at ZERO If not at zero we have to use temperature and pH to calculate the Unionized Ammonia levels using this chart…

Total Ammonia (level from kit) x multiplication factor (from table) = Unionized Ammonia Level Levels higher than .05 mg/l = fish being damaged Levels 2.0 mg/l or higher = fish will die

How to manage an Ammonia Problem Add phosphorus to the water Will increase plant growth Plants will recycle the ammonia in the water This should only be done in small amount, because of the risk of creating an algae bloom

The phosphorus cycle depends on the weathering of rock (rock & soil is the reservoir) Phosphorus and other soil minerals Are recycled locally In soil they are inorganic Plant convert them into organic compounds for consumers to eat Phosphorus is an ingredient of nucleic acids, phospholipids, and ATP. It is a mineral component of teeth & bone. Weathering of rocks Geologic uplift Runoff Sedimentation Leaching Soil Plant uptake of PO43– Consumption Decomposition Rain Plants Figure 37.19

Why measure Phosphates? Enters waterways from waste Detergents Poorly treated sewage Disturbed soil (construction sites) Usually less than .1 ppm (part per million) Algae and plants take in phosphates easily so its hard to detect the source Can cause algal blooms and eutrophication (Death of a Lake)

Why measure Total Hardness? It’s a measure of calcium and magnesium Source is rock and soil 0-50ppm = soft water 50 – 100 ppm = moderately hard 200 + = very hard water Algae prefer hard water Fish are stimulated to spawn when water softens after a heavy rain or melting snow!