Freshwater Biology-Chemical Cycles in Water_Cooper

Terms in this set (51)

Biogeochemistry

This refers to the concept of global cycling of chemicals through the biotic and abiotic reservoirs

Water vapor transpires through pores in leaves
Respiration also produces water vapor
Water evaporates from lakes, oceans, and rivers
Water vapor accumulates in the atmosphere and returns to the land as precipitation

What chemical cycles are within ecosystems?

Water
Carbon
Nitrogen
Phosphorous

Carbon dioxide
Dissolved Inorganic carbon (DIC)
Dissolved Organic Carbon (DOC)
Particulate Organic Carbon (POC)

Diffuses between water and atmospheric air

Dissolved Inorganic Carbon (DIC)

Carbon dioxide, carbonic acid and bicarbonate ion

Dissolved Organic Carbon

Methane (CH4) is simplest form from decomposition of organic matter

Particulate Organic Carbon

All organic matter: living, dead, waste etc

Carbon Reservoirs

1. Rocks: limestone and dolomite
2. Atmosphere: carbon dioxide 0.04% of air
3. Oceans: bicarbonate ions, about 26mg/L of
organic carbon
4. Freshwater: bicarbonate ions
5. Detritus: bacteria and fine organic matter
decaying
6. Primary Producers: (plants) carbonhydrates
7. Consumers: relatively small amounts

The CO2, bicarbonate, carbonate forms an equilibrium; whitening of lakes due to precipitation of carbonates

The Dark side of CO2

It can serve as an anesthetic, CO2 eruption in lake Nyos in Cameroun caused death of 1746 people

Oxygen Cycle (forms of oxygen gas)

Oxygen gas
Ozone
Inorganic
Organic

Needed for aerobic metabolism

Primarily in the upper atmosphere

Component in many inorganic molecules e.g. water, nitrate, phosphate, silicate metal oxides

Carbon, Hydrogen, and Oxygen are components of all organic molecules.

Oxygen Reservoirs

1. Rocks: mostly bound very tightly to silicon and
aluminum in clay
2. Atmosphere: Diatomic gas (O2) at about 21% in
atmosphere
3. Water: linked to photosynthesis and respiration of plants and animals

Solubility of O2 in water

Define Aerobic respiration?

The process of using glucose and oxygen to produce ATP

Breathing in Water

Phosphorous Cycle

Total Phosphorous (TP)
Soluble reactive phosphorous (SRP)
Total soluble phosphorous
Orthophosphate

Total Phosphorous

All phosphorous in water sample: 10 to 18 micrograms/liter in most lakes

Soluble reactive phosphorous

Forms readily available for algae and plants

Total soluble phosphorous

All phosphorous that can pass through a filter

Inorganic form, nearly insoluble

Forms of phosphorous

1. Dissolved organic phosphorous
2. Particulate organic phosphorous
3. Particulate inorganic phosphorous
4. Phosphine gas

From living and/or decomposing organisms; also from detergents and some pesticides

Organic phosphorous in plants and animal bodies waste

Orthophosphate bound to particular matter; electrostatic attraction to clay particles

PH3 poisonous gas produced by anaerobic decomposition of organic matter

Phosphorous reservoirs

1. Rocks: abundant in rocks
2. Soil: high in agricultural soils
3. Guano: bird or bat droppings
4. Atmosphere: small amounts in particulates (dust)
5. Oceans: poorly soluble, especially in more
alkaline saltwater, precipitates out to form
sediment layers
6. Freshwater: precipitates out with calcium and
magnesium and clay particles
7. Primary producers: Limiting nutrient for most
primary production
8. Consumers: obtained in diet and excess is
excreted

Total nitrogen (TN)
Nitrogen gas
Nitrate (NO3) Nitrite (NO2)

All nitrogen in water sample except nitrogen gas

Dissolve easily in water, but inert

Nitrate and Nitrite

forms oxides of nitrogen in water; nitrate is used by many plants, protists and microbes as a nitrogen source; nitrite is toxic

Forms of Nitrogen

Ammonia
Organic nitrogen compounds

Nitrate + nitrite + ammonium

dissolved inorganic nitrogen (DIN)

Nitrogen Reservoirs

1. Rocks: common in igneous rocks
2. Atmosphere: about 78% of the air
3. Oceans: Very soluble in water.
4. Freshwater: readily dissolves; unavailable to
plants or animals without bacteria fixation
5. Primary producers: Used by photosynthetic
plants, protists and bacteria
6. Consumers: Animals and fungi consume
autotrophs and use nitrogen to build proteins

Biological processes involving nitrogen in freshwater

Nitrogen fixation
Nitrification
Denitrification
Assimilation
Excretion

Nitrogen fixation

Nitrogen gas to ammonium

Ammonium to nitrate or nitrite

Denitrification

Nitrate to nitrogen gas

DIN or organic nitrogen incorporated into organic compounds

Elimination by animals in ammonium, urea or uric acid

Nitrogen Fixation bacteria

Nitrogen gas to ammonia; symbiotic relationship with plants; bacteria gets sugar from plants and plants gets usable forms of nitrogen

Nitrogenous waste products

Silicon in water; found in water as silicate acid;
usually 13mg/L in water

Any chemical, physical, or biological change in the environment that harms living organims

Excessive nutrients that ultimately lead to oxygen-poor water; cannot sustain much life

Describes an organism's position in the food chain

How much energy is transferred from one trophic level to the next?

Define Bioaccumulate/ biomagnify?

The concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely disbursed

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