phosphorus and nitrogen Flashcards

1
Q

is phosphorus readily available

A

Not readily available (i.e., not a lot in the atmosphere, like
carbon and nitrogen

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2
Q

where is phosphurs derived from

A

rock weathering

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3
Q

why does P not easily leach

A

Clay particles in soils tend to bind it tightly so it doesn’t easily leach

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4
Q

what are the 4 forms of P

A

Particulate P, Dissolved P, PIP (particulate inorganic phosphorus) , Phosphine Gas PH3 – highly toxic and flammable

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5
Q

how are rocks a P reservoir

A

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

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6
Q

what environments have the highest P and the lowest P

A

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

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7
Q

Stratification and P

A

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.

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8
Q

Recycling of P

A

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

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9
Q

Luxury Consumption of P

A

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

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10
Q

how do we affect the phosphorus cycle?

A

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)

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11
Q

what are the differernt types of nitrogen

A

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)

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12
Q

Total Nitrogen

A

sum of all inorganic and organic forms, does not
include nitrogen gas

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13
Q

Reservoirs of Nitrogen

A

Rocks, Atmosphere, primary producers and consumers

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14
Q

nitrogen fixation

A

the process of making nitrogen (especially in the air) availible to use

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15
Q

what is step one of nitrogen fixation

A

Most Nitrogen fixation carried out by specialized bacteria that can
convert N2 to ammonia (NH3) that can be used by plants as a nutrient.

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16
Q

what are Heterocysts

A

Fix nitrogen from N2 in the air using the enzyme nitrogenase

17
Q

Our Effects on the Nitrogen Cycle

A

Burning fuel (releases large amounts of N2O, acid ppt);
* Add nitrous oxide via livestock wastes, and commercial inorganic
fertilizers (a greenhouse gas and ozone depleting substance)
* Release large quantities by destruction of forests, grasslands and
wetlands
* Add excessive nitrates to aquatic systems via agricultural runoff
* Remove from topsoil by harvesting crops, clearing land prior to
planting etc