Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Diagram 1.
Source:
https://maryjane-kgibson.blogspot.com/2022/04/what-effect-do-abiotic-cycles-have-on.html
Temperate forests rely on a continuous cycle of decomposition and nutrient return to maintain productivity. When leaves fall from trees in autumn, they accumulate as leaf litter across the forest floor. This
dead organic material represents a large reservoir of stored energy and matter, but it is not yet available for use by plants. The transformation of leaf litter into usable nutrients occurs through decomposers - fungi, bacteria,
and detritivores - that break down complex organic molecules through enzymatic activity and respiration.
Mathematical patterns in decomposition rates and nutrient availability reveal how matter cycles and how energy flows through this system.
Decomposition rates vary depending on temperature, moisture, microbial abundance, and litter chemistry. In forests with low soil moisture, decomposition proceeds slowly, leaving a large percentage of mass
remaining after several months. In contrast, higher moisture levels accelerate microbial activity, leading to faster mass loss. These patterns can be quantified using decay curves that reflect exponential decreases in mass over time. As decomposers break down litter, they release nutrients such as nitrogen and phosphorus back into the soil, increasing nutrient concentrations as the growing season progresses.
Matter moves through several linked stages: from leaf litter to decomposers to soil nutrients to plant roots back into living biomass. This matter cycling pathway is mathematically reflected in the rising concentrations of nitrogen and phosphorus between April and August as decomposition progresses. Although matter cycles continuously, the flow of energy is unidirectional. Decomposers use the chemical energy stored in leaf litter to fuel metabolism, releasing CO2 and heat. This energy cannot be reused by plants; instead, plants must rely on sunlight to create new energy-rich molecules.
The datasets illustrate these relationships. Leaf litter shows predictable mass-loss curves under different moisture conditions, while soil nutrients rise in a pattern that matches increased microbial activity. These relationships demonstrate that mathematical representations - such as decay curves, rate comparisons, and
nutrient accumulation graphs - can be used to support claims about matter cycling and energy flow in forest
ecosystems.
Together, the patterns in decomposition and nutrient availability demonstrate a core principle of ecology: energy flows and diminishes, while matter cycles through ecosystems in predictable, quantifiable ways.
Diagram 2.
Source: https://biologyreader.com/organic-matter-decomposition.html
Table 1.
Day | Mass Remaining 20pct | Mass Remaining 40pct | Mass Remaining 60pct |
|---|---|---|---|
0 | 100 | 100 | 100 |
20 | 88 | 82 | 76 |
40 | 74 | 64 | 56 |
60 | 63 | 50 | 39 |
80 | 52 | 38 | 28 |
100 | 45 | 30 | 20 |
Graph of Information - Figure 1.
Diagram 3.
Table 2.
Month | Soil Nitrogen mg/kg | Soil Phosphorus mg/kg |
|---|---|---|
Apr | 14 | 6 |
May | 18 | 7.5 |
Jun | 22 | 9 |
Jul | 27 | 10.2 |
Aug | 31 | 11.4 |
Sep | 29 | 11 |
Graph of Information - Figure 2.
According to Table 1, at 40 days, which moisture condition retains the highest percentage of mass?
Using Table 1 and Figure 1, describe how moisture level affects the rate of leaf litter decomposition over the 100-day period.
Using Diagram 1 and the reading, explain how soil moisture and temperature act as limiting factors that affect nutrient availability for trees.
Based on Table 2, during which month is soil phosphorus at its highest level?
Using Table 2 and Figure 2, describe the relationship between soil nitrogen and soil phosphorus as decomposition progresses from April to September.
Explain how mathematical patterns in decomposition and nutrient accumulation support claims about ecosystem change in a temperate forest.
Include a claim, evidence, and reasoning in your response.