Writing prompt Grade 9 English Language Arts
Mirror Lake's Algal Blooms: A Grade 9 Argument Writing Prompt
A grade 9 argument prompt on whether a lake town should require farm buffer strips to reduce nutrient runoff, addressing a farmer's counterclaim about cost.
Objectives
- Students will write an argument essay that states a claim about a proposed water-quality ordinance, using valid reasoning and relevant evidence.
- Students will address a counterclaim a stakeholder might raise and rebut it using reasoning grounded in the background material.
- Students will explain the process of eutrophication and its effect on dissolved oxygen using evidence from the background reading.
Vocabulary
- Eutrophication
- Eutrophication is what happens when a lake or bay gets overfed with nutrients: algae grows out of control, and when it dies and rots, the water loses the oxygen that fish need.
- Algal bloom
- An algal bloom is a fast, thick growth of algae that can turn a lake green and scummy. Blooms happen when the water gets lots of nutrients and warm sunshine, and some blooms make toxins.
- Nonpoint source pollution
- Nonpoint source pollution is pollution that washes off the land a little at a time from many places, like lawns, streets, and farms, instead of coming out of one pipe. It is the hardest kind of water pollution to control.
Teacher overview
Cedar Hollow, a fictional lake town used for this prompt, borders Mirror Lake, also fictional, which is fed by streams that run through the surrounding farmland. For the past two summers, the lake has developed thick green algal blooms that were not a problem before. The town council is deciding whether to require farms near the lake to maintain vegetated buffer strips, planted areas that filter runoff before it reaches the water, and to limit how much fertilizer can be applied close to the shoreline. This prompt asks students to take a position on that ordinance and to answer a farmer's likely objection with reasoning grounded in the science of the problem.
Prompt
Background: Fertilizer and animal waste contain nitrogen and phosphorus, nutrients that plants need to grow. Rain washes those nutrients off farm fields and into the lake. There they feed a fast burst of algae growth called an algal bloom. This kind of runoff is called nonpoint source pollution, because it comes from many spread-out places rather than from one pipe. Algae do not live forever. When older algae die, bacteria in the water decompose them, and that decay uses up dissolved oxygen from the lake. Most fish and other aquatic organisms need dissolved oxygen above about 5 milligrams per liter (mg/L) to survive comfortably. A large enough bloom can push oxygen levels low enough to threaten fish and other wildlife. This chain of nutrient overload, algae growth, and oxygen loss is called eutrophication. A vegetated buffer strip is a band of grasses, shrubs, or trees planted along the water's edge. It can absorb and filter out a meaningful share of the nutrients in runoff before they reach the lake.
Writing task: Cedar Hollow's town council is deciding whether to pass an ordinance requiring buffer strips along Mirror Lake and limiting how much fertilizer can be spread near the shoreline. Write an argument essay that states a clear claim on whether the council should pass it. Address at least one counterclaim a farmer near the lake might raise, and support your position with evidence from the background material above.
Planning Organizer
| Category | Your notes |
|---|---|
| Claim (should Cedar Hollow pass the ordinance?) | |
| Reason 1 + evidence from background material | |
| Reason 2 + evidence from background material | |
| Counterclaim a farmer might raise | |
| Your rebuttal to the counterclaim | |
| Concluding statement |
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Exemplar & Rubric
Exemplar response:
Cedar Hollow's town council should pass the buffer-strip ordinance, because Mirror Lake's algal blooms are a direct result of nutrient runoff that a buffer strip is specifically designed to reduce. Fertilizer and animal waste washing off nearby fields carry nitrogen and phosphorus into the lake, and once those nutrients arrive, they feed the kind of rapid algae growth the lake has seen for two summers running. A vegetated buffer strip planted along the shoreline would filter out a meaningful share of those nutrients before they ever reach the water, addressing the cause of the problem rather than only its symptoms.
The blooms are not simply unattractive; they threaten the lake's fish and other wildlife. As algae die, bacteria decompose them, and that decomposition uses up dissolved oxygen, which most aquatic organisms need above about 5 mg/L to survive comfortably. A lake with repeated blooms risks dropping below that level, which could mean a die-off of fish that residents catch and swim among every summer. Requiring buffer strips is a direct response to a problem with a real biological cost, not a symbolic gesture.
Some farmers near the lake will argue that the ordinance costs them money and productive land, since a buffer strip takes acreage out of crop production and requires plants, seed, and maintenance. This is a fair concern, and the council should not dismiss it. However, the cost of losing Mirror Lake as a healthy, swimmable, fishable lake would likely exceed the cost of a buffer strip, both in the value of nearby property and in the years it could take a badly degraded lake to recover once fish populations and water clarity decline. The council could also pair the ordinance with a cost-sharing program that helps farmers cover part of the planting cost, easing the burden without abandoning the requirement.
Cedar Hollow's town council should pass the ordinance. The connection between fertilizer runoff, algae growth, and falling oxygen levels is well established, and a buffer strip is a proven, direct response to that chain of cause and effect.
Rubric:
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Claim | No clear position stated | States a position but it shifts or is vague | States one clear, consistent position on the ordinance | States a clear position and previews the essay's reasoning |
| Evidence & reasoning | No evidence from background material | Restates one fact without explaining its relevance | Uses at least one specific detail from the background material and explains how it supports the claim | Uses two or more specific details and explains how each connects to the claim about the ordinance |
| Counterclaim | No counterclaim addressed | Mentions an opposing view without a rebuttal | States a counterclaim and offers a rebuttal | States a counterclaim, rebuts it specifically, and ties the rebuttal back to the claim |
| Organization & conventions | Ideas are disconnected; frequent errors interfere with meaning | Some organization; errors are noticeable but do not block meaning | Clear paragraph structure; few errors | Clear, purposeful structure with a strong concluding statement; virtually error-free |
Differentiation
Support (below grade level)
Provide sentence starters for each Planning Organizer row ("One reason Cedar Hollow should/should not pass the ordinance is ___, because the background material says ___.") and allow the counterclaim and rebuttal to be combined into a single simpler sentence rather than a full paragraph.
Extension (above grade level)
Ask students to describe, using only the background material provided and not outside sources, what a cost-sharing program for buffer strips might look like, and add a second counterclaim addressing whether the town or the farmers should pay the greater share of that cost.
ELL supports
Pre-teach nonpoint source pollution, algal bloom, and buffer strip with a labeled diagram showing rain carrying fertilizer from a field, through a planted buffer strip, and into a lake. Allow the Planning Organizer to be completed with phrases rather than full sentences before drafting begins.