phosphorus and nitrogen Flashcards
is phosphorus readily available
Not readily available (i.e., not a lot in the atmosphere, like
carbon and nitrogen
where is phosphurs derived from
rock weathering
why does P not easily leach
Clay particles in soils tend to bind it tightly so it doesn’t easily leach
what are the 4 forms of P
Particulate P, Dissolved P, PIP (particulate inorganic phosphorus) , Phosphine Gas PH3 – highly toxic and flammable
how are rocks a P reservoir
PO4 is often present as the mineral apatite (tricalcium phosphate - a component of igneous rocks) and as a minor component of limestone as well as a
variety of other rare minerals
what environments have the highest P and the lowest P
Lowest in mountainous regions of crystalline bedrock
geomorphology
* Increases in lowland waters derived from sedimentary rock* Lakes rich in organic matter (e.g., bogs) have high [Total P
Stratification and P
thermal stratification strongly influences the amount of available phosphate. As
lakes stratify in the summer, PO4 begins to be removed from the epilimnion to
the hypolimnion, where it is basically trapped until the lake turns over.
Recycling of P
zooplankton and fishes play a major role in recycling phosphate in lake water. They eat algae, then excrete organic P back into the water; taking the P from a particulate form that could sink into the hypolimnion and converting it into a soluble form that is more likely to stay in the
epilimnion
Luxury Consumption of P
When PO4 is available algae take it up at a high rate and store it for future generations – each time they divide the phosphate store is partitioned among the daughter cells. The smaller the alga, the higher it’s surface to volume ratio – the greater its ability to take up phosphate
how do we affect the phosphorus cycle?
Mining phosphate-rich rocks to make commercial inorganic fertilizers
* Applying large amounts to agricultural fields that runoff into bodies of
water causing eutrophication (algal blooms)
* Reduce phosphate in tropical soils by trying to cultivate them (also going
to aquatic environment)
what are the differernt types of nitrogen
Organic Nitrogen Compounds:
* Amino Acids (R-NH3) – the building blocks of proteins;
* Nucleotides – DNA, RNA and ATP;
* Excretory products – urea CO(NH2)2 and uric acid (C5H4N4O3).
Inorganic Nitrogen Compounds:
* Ammonia (NH3); Ammonium (NH4+)
* Nitrate (NO3-) and Nitrite (NO2-)
* NO – nitric oxide, nitrous oxide (N2O), Nitrogen gas (N2)
Total Nitrogen
sum of all inorganic and organic forms, does not
include nitrogen gas
Reservoirs of Nitrogen
Rocks, Atmosphere, primary producers and consumers
nitrogen fixation
the process of making nitrogen (especially in the air) availible to use
what is step one of nitrogen fixation
Most Nitrogen fixation carried out by specialized bacteria that can
convert N2 to ammonia (NH3) that can be used by plants as a nutrient.
