Download Phosphorus Cycle

Phosphorus Cycle
Phosphorus
 Key
element in cell membranes, in
making DNA, calcium phosphate in
bones
 2 cycles
– Short term – living organisms
– Long term – Earth’s crust
Phosphorus Cycle
 Phosphorus:
usually found in
phosphorus ions (PO43-).
– usually found in rock.
– soluble and dissolve in water.
– when dissolved in water – plants
absorb the phosphorus with the water.
Phosphorus enters the food chain.
Decomposers free the phosphorus by
decaying organisms.
Cycle cont’d
 Potassium,
calcium, magnesium also
are nutrients that cycle
 Decomposition rate (speed) is linked
to cycling rate
– Decomposition in rain forests occur
quickly (few months)
– Decomp occurs slowly in tundra (50
years)
Two most important abiotic factors
regulating decomp 1) _______ 2) _______
Erosion
 Erosion
from precipitation removes
phosphorus from rocks.
– Carries to rivers and ocean.
– In the ocean: phosphorus forms
sediments on ocean bottom.
– These phosphorus sediments over
millions of year are pushed up to the
land surface.
Phosphorus
 The
majority of phosphorus enters
the food chain, the minority in
oceans.
 Without photosynthesis, phosphorus
cannot enter the food chain.
 Thought Question: Describe how the
phosphorus cycle is linked to the
water cycle and photosynthesis.
Fertilizer
 When
crops are harvested for food
phosphorus and nitrogen are
removed.
 Over time the soil nutrients are
depleted.
 Fertilizer is used to restore
phosphorus and nitrogen.
Proper use of fertilizer
 Fertilizer
used in excess can cause
problems such as:
– Run off into water table
Can kill fish and affect drinking water.
– Can produce very acidic soil
–Fertilizer must be used correctly in
the right amounts.
Thought Question
 Thought
Question: What are the
positives and negatives of using
fertilizer?
 1.
Assignments – Unit Final
Review
“Asian Brown Cloud” – handout
(counts as a double assignment)
Due: Friday, February 25th
 2.
Complete questions on pg. 66
– Omit:5, 16, 17, 22 (completion mark)
3. Review notes on page 72
4. Questions
pg 73-75 – OMIT:16-20,28,31-35,37,38
pg 76-79 – OMIT: 22-27, 34, 41,42,43