Initial Publication Date: September 23, 2025

Dead Zones MEL

The Dead Zones MEL asks students to investigate whether and how aquatic dead zones may be repaired. A dead zone is an area of water that is low in oxygen. Aquatic life cannot survive in a dead zone.

MEL Activities

There are two forms of this MEL Dead Zones Activity....a pre-constructed (pcMEL) and a build-a-MEL (baMEL). The pcMEL limits student choices, which may be good for the first time the activity is introduced to a class or if you are working at earlier grade levels. The baMEL allows more choices, which may be good for students who have used the MEL before or are at an advanced grade level. Below the activity links are additional teaching resources that will help students learn more about fundamental scientific principles of dissolved oxygen, nutrient use, and human activity.

Overview

This slide deck provides an introduction to the Dead Zones build-a-MEL (baMEL). It is useful even if you are using the Dead Zones pcMEL with your students. The primary difference between the pcMEL and the baMEL is that with the pcMEL students are given two models and four lines of evidence in a preconstructed diagram where as with the baMEL students choose two models from three and select four lines of evidence from eight to create their own MEL diagram.

MEL Activity: Dead Zones baMEL front slide

MEL Activity: Dead Zones baMEL (Acrobat (PDF) 1.9MB Jul25 24)

Next Generation Science Standards Performance Expectations

MS-ESS3-2: Earth and Human Activity

Analyze and interpret data on natural hazards to forecast future catastrophic events and inform the development of technologies to mitigate their effects.

HS-ESS3-4: Earth and Human Activity

Use a model to describe how variations in the flow of energy into and out of Earth systems result in changes in climate.

Lateral Reading (LR) Resources

What does it mean for a source to be credible? Why should we investigate whether a source is credible before we read it? How do we decide whether online sources are credible? Use lateral reading to find out.

Use lateral reading to evaluate the credibility of three sources related to dead zones.

These LR sources connect to Evidence #1: Methods to maintain healthy nutrient levels in bodies of water do not always work. Water nutrient levels return to normal when human overuse of fertilizer stops.

LR Guiding Questions (Acrobat (PDF) 28kB Jun8 23)
Source A: Is Too Much Fertilizer a Problem?
Show me information about the source
Source B: Five important facts about fertilizers
Show me information about the source
Source C: dead zones
Show me information about the source

Lateral Reading Teacher Guide

Other Resources

This Plausibility Ranking Task (PRT), which may be completed prior to using any MELs, helps students to understand the role of evidence in supporting or refuting models.