Download BIOLOGY 154: ECOLOGY and ENVIRONMENTAL ISSUES

BIOLOGY 157:
LIFE SCIENCE: AN
ENVIRONMENTAL APPROACH
(Nutrients & Biogeochemical Cycles)
NUTRIENTS AND NUTRIENT
CYCLING
• NUTRIENTS:
are elements (C, H, N, etc.) and simple
inorganic compounds of these elements (H2O,
CO2, etc.) that are essential for life.
• FOODS:
are organic compounds (contain carbon,
hydrogen, usually oxygen and sometimes
other elements) that organisms use to fuel
their metabolism. Foods would include lipids
(fats and oils) carbohydrates (sugars, starch,
etc.) and proteins.
Essential Minerals (Nutrients)
needed by Animals AND Plants)
Major Elements
(= Macronutrients)
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
Phosphorus (P)
Calcium (Ca)
Potassium (K)
Sulfur (S)
Magnesium (Mg)
Sodium (Na)
Trace Elements
(= Micronutrients)
Iron (Fe)
Manganese (Mn)
Zinc (Zn)
Molybdinum (Mo)
Chlorine (Cl)
Copper (Cu)
Vanadium
Silicon (Si)
Cobalt (Co)
TRACE Essential Minerals
(= Nutrients)
• needed by certain animals or plants
• Boron (B), Chromium (Cr), Fluorine (Fl),
Iodine (I), Nickle (Ni), Selenium (Se), Tin (Sn)
BIOGEOCHEMICAL CYCLES (I)
• The more or less circular paths of the chemical
elements passing back and forth between
organisms and environment are known as
Biogeochemical Cycles (also called Nutrient
Cycles).
• Essential elements are rarely (if ever)
homogeneously distributed, nor present in only
one chemical form throughout an ecosystem.
These materials exist in compartments or pools
which have varying exchange rates between
them.
BIOGEOCHEMICAL CYCLES (II)
• From the standpoint of the earth as a whole,
Biogeochemical Cycles Fall into two groups:
• Perfect (= gaseous) cycles
cycles (nitrogen, carbon, oxygen) that have a large
gaseous, rather easily exchangeable, reservoir which
makes them less likely to get out of balance for long
periods of time over large areas
• Imperfect (= sedimentary) cycles
cycles (calcium, phosphorus, iron) that involve the more
earthbound elements and large portions of the supply
may become unavailable for long periods of time over
large areas (thus disturbing the cycle)
AVAILABILITY OF NUTRIENTS
• Even if the nutrient elements are in the soil
and/or water of an area, they may be
unavailable to organisms.
• Some organisms can only utilize an element
when it is present in a specific compound.
• pH also affects the availability by either
changing the chemical form of the element or
simply by interfering with the uptake of that
substance
pH & RELATIVE NUTRIENT AVAILABILITY
EXAMPLES OF
BIOGEOCHEMICAL CYCLES
• Generalized Cycle
• Sedimentary Cycles
– Calcium
– Phosphorus
• Gaseous Cycles
– Nitrogen
– Carbon
GENERALIZED BIOGEOCHEMICAL CYCLE
CALCIUM CYCLE
PHOSPHORUS CYCLE
TROPHIC LEVEL CONCENTRATION
• DEFINITION:
The selective retaining of certain elements or
compounds by an organism so that the
concentration builds up in these organism above
what it is in their immediate habitat and/or food
• AKA: trophic level magnification, biological
concentration or biological magnification
• T. L. Concentration can occur for:
essential materials (even to toxic levels)
non-essential materials (many are toxic)
TROPHIC LEVEL CONCENTRATION
NITROGEN CYCLE (I)
NITROGEN CYCLE (II)
CARBON CYCLE (I)
CARBON CYCLE (II)
PLEASE NOTE
• You are not responsible for the Sulfur Cycle
diagram on p. 45 of your text.
What you need to know about sulfur and the
sulfur cycle at this time is:
• Sulfur compounds are a major contributor to
acid precipitation
• Sulfur may be involved in a feedback loop that
helps to stabilize temperatures