Bob Zhang
Science 10 (Blk 2-3)
Oct 17, 2011
2.2 – Nutrient Cycles in Ecosystems
P91
#
1
Question
Use the following nutrient cycle
diagram to answer questions (a) to
(d). Diagram on P91.
Answer
(a) Land, atmosphere, oceans, marine
sediments and sedimentary rock, nutrient
stores.
(a) Identify the abiotic components
(b) Producers, composers, decomposers
(b) Identify the biotic components
(c) Some arrows are thicker than others
because they show the amount and speed in
which nutrients move into and out of stores.
(c) Why are some arrows thicker
than others
(d) What would you add to this
diagram to show the processes by
which nutrients naturally leave
stores in rock?
2
Describe the importance to living
organisms of each of the following?
(a) Carbon is an essential nutrient that is
required to sustain life.
(a) Carbon
(b) Nitrogen is an important part of DNA and
proteins, which are needed to sustain life.
(b) Nitrogen
(c) Phosphorus
3
(d) I would add weathering and the specific
nutrient cycled.
Explain how each of the following is
stored in the biosphere.
(a) Carbon
(b) Nitrogen
(c) Phosphorus
(c) Phosphorus is essential for life as it mixes
with carbon to strengthen bones, and assist in
root development, stems, and seed production.
(a) Carbon is stored in the atmosphere, in
oceans, in organisms, and mainly in
sedimentary rock.
(b) Nitrogen is stored mainly in the
atmosphere, but exists in organisms and
oceans as well.
(c) Phosphorus is stored in phosphate rock,
oceans, and in organisms. It is not stored in
the atmosphere as gas.
4
In what form is carbon stored in the
ocean?
Carbon is stored in aquatic plants, and is
stored as dissolved carbon dioxide.
5
Explain how human activities have
influenced:
(a) Mining for carbon, burning of fossil fuels,
agriculture, industry, domesticated plants
(a) Carbon
(b) Clearing forests by burning, and by burning
grasslands. Chemical fertilizers and fossil fuel
burning also contributes. Affects via acid rain
(b) Nitrogen
(c) Phosphorus
(c) Mining of phosphate rock and guano.
Fertilizers detergents and improperly treated
wastes, including human sewage. Burning
forests
6
How does geologic uplift contribute
to the phosphorus cycle?
During geologic uplift, phosphate rock is
exposed, and weathering begins to release the
phosphorus from the phosphate.
7
The following processes circulate
carbon in an ecosystem. Identify
which processes circulate carbon
and which processes circulate
carbon very slowly.
(a)The process of photosynthesis is fast, but
the amount per round is little.
(a) Photosynthesis
(c) The process of sedimentation is slow, but
the amount per round is a lot
(b) Volcanic activity
(c) Sedimentation and rock
formation
(b) The process of volcanic is can be fast or
slow, and the amount per round is a lot.
(d) The process of respiration is fast, but the
amount per round is little.
(d) Respiration
8
Explain the term “leaching”.
Leaching is when water runs over soil, and
picks up nutrients, and carries it into rivers or
lakes.
9
List three ways in which plants
influence the cycling of nutrients.
Plants influence the cycling of nutrients by:
(a) photosynthesis
(b) cellular respiration
(c) acting as a nutrient store
10
Match the following processes with
the descriptions.
(a) Nitrogen
Fixation
(i) Nitrate is
converted to
nitrogen gas
(b) Nitrification
(ii) Ammonium
is converted
to nitrate
(c)
Denitrification
(iii) Nitrogen
gas is
converted to
nitrate
(a) matches with (iii)
(b) matches into (ii)
(c) matches into (i)
11
Explain the relationship between
Rhizobium bacteria and plants
Rhizobium fixes bacteria and converts N2 into
NH4+, a form of nitrogen usable by plants.
12
How can lightning benefit an
ecosystem?
Lightning is a form of nitrogen fixation.