How Limiting Nutrients Paint the World We Breath

What’s Growing On...

Making Air out of Oceans:

How limiting nutrients paint the world we breath.

Summary

In this two-part lesson, students will create a graph using data collected by scientists (Dr. Alex Worden and Dr. Amy Zimmerman) to test their predictions about the effects of nutrients (nitrogen and phosphorous) on the abundance of phytoplankton (Ostreococcus) in the world’s oceans. Students will then use a blank world and an interactive map database to make and analyze predictions about what parts of the world’s oceans are the most biologically productive. Throughout this activity, students will answer written prompts that ask them to think critically about the data they are working with and the larger processes they are analyzing. This assignment can be done individually or in small groups.

TAGS: phytoplankton, nutrients, nitrogen, nitrates, phosphorous, phosphates, limiting factors, graphing, interactive maps, writing, critical thinking, being awesome...

Key Concepts

●Nutrients and the roles certain ones (nitrogen and phosphorous) play in the development and abundance of phytoplankton (and all living organisms in general).

●Limiting factors - how certain nutrients can determine the relative abundance of biological productivity in the world’s oceans.

●LS1.C: Organization for Matter and Energy Flow in Organisms.

●LS2.B: Cycles of Matter and Energy Transfer in Ecosystems.

Objectives

●Students will use prior knowledge to make predictions about the effects of certain nutrients on the development and abundance of living organisms.

●Students will use a data set to create a graph of the effects of various amounts of nitrogen on phytoplankton abundance.

●Students will interpret, summarize, and communicate their understanding of the key concepts by analyzing the graph and map activities in writing prompts throughout the assignment.

Materials

●Making Air out of Oceans student handout. This can be assigned to students electronically as a google doc either as a template or using google classroom.

●Computers or laptops for the data analysis and graphing activity in part 1.

●Computers, laptops, or tablets for the interactive map activity in part 2.

●Blank world maps printed and color pencils for the mapping activity in part 2.

Procedure

Background/Intro - have students read this individually or aloud paragraph by paragraph.
Paragraph 1. Have images of various types of phytoplankton on screen for students to view (there are a couple on the handout).
Paragraph 2. Briefly explain the concept of limiting factors after students have read paragraph. Also explain that certain materials/nutrients can be harmful if present or overabundant in an ecosystem. Have students come up with a list of nutrients that living organisms require - they can do this individually or in small groups and write their answers on their handout. You can then review these as a class.
Part 1 - Plankton data activity. Have images of phytoplankton on screen when going over the intro to this activity. These images are great review/representations of a chloroplast and you can review how they function. Living things need more than sugar to survive though! Remind students of the nutrients you discussed in the background/intro that are essential for living organisms.
Step 1 - You are asking students to predict what they think the outcome will be if you were to add nitrogen to a sample of phytoplankton. In this part, let the students make their own predictions - do not direct their thinking on this. Let them then come up with their own explanation and reasoning for their prediction. This will allow you to assess their prior-knowledge and possible misconceptions about the role of nitrogen in ecosystems.
Step 2 - Assign each student or group of students a data set to work with. Students are to select the data outlined in red and graph it.
Allow students to select which type of graph they think best represents the data. A line graph is the best choice however, as you are showing change over time - but a bar graph also works as the data was collected at discrete intervals.
Once students have made their graph - labeling their axes and titling their graph is the most important part. A sample graph is provided for you on a separate tab - and you will want to delete this from the copy of the data set you provide to your students. Students can use the explanation of the data set to help them label their axes and title their graph. You may have to guide your students through this process depending on their ability to read through the scientific language of the explanation provided. A link to the paper is also provided - this could be assigned as homework prior to this activity or reviewed in class or in small groups.
Insert the graph into the student handout. Click on the tiny box with the inverted triangle in the top right of your graph. Select “save image”. Save the graph as an image to your download folder. In the student handout, have students then put their cursor where they want to put the graph and click on “insert”, then “image”, and select the image of the graph saved in the download folder.
The explanation of the data and graph is the final assessment component of this part of the activity. This should be a well-written and detailed paragraph. Students should cite specific numbers and trends from their graph in their discussion. A simple rubric using common core language can be developed to score student paragraphs.
Part 2 - Painting the world we breath… Review the key concepts from part 1 about the role of certain nutrients in ecosystems and also what a limiting factor is.
Step 1 - provide each student with a blank map of the world.
Have students label with the letter “P” on their map what parts of the world’s oceans they think are the most biologically productive. Remind to label only the parts they think will be the most productive...and not go to label crazy.
Do not direct student thinking on their explanations for the labeling choices in this part. Let them then come up with their own explanation and reasoning. This will allow you to assess their prior-knowledge and possible misconceptions about what parts of our planet’s oceans are most productive and why.
Step 2 - Direct students to the NOAA interactive map website.
Have students follow the directions outlined in the student handout for creating their own interactive map of annual, surface nitrate distribution.
Students can use color pencils (or just shade) to fill-in their blank map showing where nitrates (accessible nitrogen) is most abundant globally in the world’s oceans.
Do the same for phosphates (accessible phosphorous).
Students should circle the three regions on their map that they now think will be the most productive based on the shading of available nutrients.
Students should write a paragraph for #4 that explains the distribution patterns. Factors include proximity to land (sources for nutrient runoff), major rivers outflows (sources of nutrient runoff), water temperature (colder waters can hold higher concentrations of nutrients - including oxygen), and global wind patters (these disperse nutrients across the oceans in distinct annual patterns). For the last part, global wind patters, students can use the NVS Explorer website to help guide their thinking.
Have students define the term “limiting factors” for #5 and then discuss how nitrogen and phosphorous serve as limiting factors in the less productive parts of the Earth’s oceans. These would be the parts that are NOT shaded on their maps. Students can refer back to the background/intro section of their handout for the definition.
Bring up the map of global chlorophyll production in the world’s oceans on the screen and discuss with the class what this map is showing. Students can also do this on their own, but it may be helpful to have a short class discussion on this before students complete this last paragraph. This part should be where students look at the actual global production of chlorophyll (the regions where photosynthesis, and thus oxygen production) is most abundant. They can then compare it to the maps they made and reflect on the process that lead to this global pattern.

Assessment

●Demonstration of understanding will come through student participation in class and and group discussion on the various components of this lesson...and also the individual completion of the student handout and map.

●Part 1: Students will produce and correctly label a graph of cell density in relation to varying amounts nitrogen over time.

●Part 2: Students will produce a map showing the distribution of nitrogen and phosphorous globally in the Earth’s oceans.

●Assessments will be written explanations where students interpret, summarize, and communicate their understanding of the key concepts by analyzing the graph and map activities in writing prompts throughout the assignment.

●Assessment rubrics for these paragraphs can be developed using common core language. An emphasis on student use and reference to data and evidence should be included in the rubric.

Additional Resources

Web resources used:

●NOAA - National Oceanographic Data Center interactive images:

●NVS - Data Explorer:

●Map of global chlPhytoplankton Cell Density data spreadsheet:

●Blank world map - student copy:

●Chlorophyll production:

Additional websites and resources:

●Dr. Amy ZImmerman’s PowerPoint presentation at the 2015 EARTH teacher workshop:

●Intern Zena Jensvold paper available at:

EARTH: PRIOR KNOWLEDGE & EXTENSION UNITS

This lesson along with the larger unit can be used with other Earth lessons and units.

Prior knowledge units:

●Microalgae: Blooms Gone Wild

Extension units:

●Microbes and Climate

●Elkhorn Slough Nitrogen Case Study