Activity Title: Eutrophication and the Gulf of Mexico Dead Zone

Subject (Focus/Topic): The lesson addresses the causes and consequences of eutrophication in the northern Gulf of Mexico.

Grade Level: • Grade Level: Community College (non-major, freshman and sophomore level students, could also be used for 9-12th grade students). • Population Characteristics: Predominantly non-major students seeking to fulfill general science course (lecture + lab) requirements. • Course: Biology 145 – Marine Biology. • Lesson Groupings: Individual, small groups (4 students), and whole class.

Average Learning Time: Five to six hours (one week of class time), with potentially additional time needed for activities related to the stakeholder discussion/debate.

Lesson Summary (Overview/Purpose): Students will use satellite imagery data together with CTD and shark population data collected during a longline shark survey aboard the NOAA Ship Oregon II to determine the causes and consequences of eutrophication in the northern Gulf of Mexico.

Overall Concept (Big Idea/Essential Question): Students will investigate the factors that influence where organisms can live in the ocean and how human activities affect marine habitats. Students will also learn how scientists study the physical, chemical, and biological properties of the ocean.

Specific Concepts (Key Concepts): As a result of this lesson, students will understand: 1. Factors that influence where marine organisms live in the ocean. 2. The causes and consequences of eutrophication and the formation of northern Gulf of Mexico dead zone. 3. How marine scientists collect and analyze data about the ocean including temperature, dissolved oxygen levels, salinity, primary productivity, and populations of marine organisms.

Focus Questions (Specific Questions): 1. What factors influence the distribution of marine organisms in the ocean? 2. What is eutrophication? 3. How do human activities cause eutrophication and formation of hypoxic/dead zones in the northern Gulf of Mexico? 4. How does eutrophication affect the distribution of marine organisms? 5. What are the effects of eutrophication on Gulf of Mexico fisheries, ecosystems, and tourism? 6. How do scientists use a CTD and satellite imagery to collect and analyze data about ocean temperature, salinity, dissolved oxygen, and primary productivity? 7. How do scientists collect and analyze data about populations of sharks in the Gulf of Mexico? 8. How can we address the problem of eutrophication in the Gulf of Mexico?

Objectives/Learning Goals: Upon completion of this lesson, students will be able to: 1. Summarize and illustrate how human activities affect the amount of nutrients in the ocean that contribute to eutrophication and the formation of dead zones through participation in an in-class discussion. 2. Analyze and interpret data from CTD sensors in order to locate hypoxic zones with 90% accuracy. 3. Predict the effect of hypoxic zones on marine organisms through the ability to analyze and interpret shark population data from a NOAA Longline Survey with 80% accuracy. 4. Demonstrate functional numeracy through the ability to create and interpret graphs, tables, and statistical information with 80% or better accuracy. 5. Evaluate and argue how various groups (agriculture, livestock, industry, urban/suburban planning, fisheries, scientific community, policy makers) can work to limit eutrophication in the Gulf of Mexico through participation in an in-class debate and discussion. 6. Create a written assessment of their understanding of a new concept including any unanswered questions or unsolved problems (self-reflection) by completing a learning journal that includes: (i) a summary of what they did, (ii) a description of what they learned, and (iii) and a description connecting what they learned with what they already know.

Background Information: Information about Photosynthesis and Cellular Respiration: Students should have a basic understanding of photosynthesis, cellular respiration, and nutrient requirements of living organisms in order to understand eutrophication and the effect of low oxygen levels on marine habitats.

Photosynthesis is the process used by plants, algae, and some bacteria to capture energy from the sun and use this energy for the production of basic nutrients (carbohydrates, fats, and proteins) needed for growth and survival. Photosynthetic organisms use specialized pigments, primarily chlorophyll, to capture sunlight, which is converted to chemical energy to drive the biochemical reactions of photosynthesis. The products of photosynthesis include glucose and other molecules needed for the synthesis of amino acids, fatty acids, and nucleic acids. Production of amino acids (for protein synthesis) and nucleic acids (for DNA and RNA synthesis) also requires uptake of nitrogen from the environment. Excess nitrogen from a variety of sources enters streams and rivers and is carried to the oceans, where high levels of nitrogen can affect the growth of marine organisms.

Cellular respiration is the process by which organisms break down molecules such as glucose to produce ATP (adenosine triphosphate), which is used by cells to perform work. Cellular respiration can function either anaerobically (without oxygen) or aerobically (with oxygen). Aerobic respiration is much more efficient and oxygen is required by most organisms to thrive. Thus, in the oceans, dissolved oxygen levels are an important factor that will determine where marine life can survive. Eutrophication can lead to hypoxia, which occurs when dissolved oxygen levels are too low to support most aquatic life (typically below 2 mg/l).

Information about Monitoring the Ocean: This lesson will introduce students to the use of a CTD (Conductivity/Temperature/Depth Recorder) and satellite imagery to gather information about the oceans. A CTD is used to gather information about the essential physical properties of ocean water. It gives scientists a precise and comprehensive charting of the distribution and variation of water temperature, salinity, and density that helps to understand how the ocean affects life. By measuring conductivity (how easily electrical currents pass through water), scientists can get a measurement of a water sample’s salinity (salt content). A special platinum thermometer is used to measure temperature and a pressure sensor is used to determine the depth of the water (depth and pressure are directly related). The CTD is deployed by hooking it onto a cable that is lowered from the ship into the water. The CTD records data continuously as it descends to the bottom and ascends back to the surface.

In this lesson, students will analyze CTD data collected in September 2015 aboard the NOAA Ship Oregon II during the Shark Longline Survey in the northern Gulf of Mexico. Students will focus their work on analyzing the levels of dissolved oxygen at various locations and depths to understand the relationship between these data and the abundance of phytoplankton and marine animals (primarily sharks).

Satellite imagery is used to monitor a number of physical, chemical, and biological properties of the ocean. In this lesson, students will explore the use of satellites to monitor the concentration of chlorophyll in the ocean using NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) satellite. Levels of chlorophyll (measured in mg/m3) in surface waters of the ocean are directly related to the abundance of photosynthetic organisms (phytoplankton) in the water. Students will determine the spatial and temporal distribution of phytoplankton in the Gulf of Mexico and compare these data to CTD data and shark catch data to learn how phytoplankton abundance relates to levels of dissolved oxygen and abundance of marine animals.

Common Misconceptions/Preconceptions: 1. Humans living away from the coasts have little impact on the ocean and marine organisms. 2. The oceans have similar physical, chemical, and biological properties everywhere including at the surface and at depth. 3. The ocean, unlike land, is relatively uniform and does not have many unique habitats and ecosystems.

Materials: List all the materials necessary to teach this lesson. 1. Copies of the CTD data collected aboard the NOAA Ship Oregon II. 2. Copies of the shark survey data collected aboard the NOAA Ship Oregon II.

Technical Requirements: List any technical resources needed to teach the lesson. 1. Computers to access NOAA Environmental Imaging data (https://www.nesdis.noaa.gov/) 2. NOAA Ocean Observing System (https://ioos.noaa.gov/) 3. And NASA Ocean Color Data (https://oceancolor.gsfc.nasa.gov/) 4. Computers for CTD and shark number data analysis using Excel spreadsheets.

Teacher Preparation: 1. Read information at http://www.gulfhypoxia.net/Overview/ and http://coastalscience.noaa.gov/research/pollution/hypoxia/default to become familiar with the causes and consequences of eutrophication in the northern Gulf of Mexico. 2. Become familiar with the use and analysis of CTD and satellite imagery data to monitor physical, chemical, and biological properties of the ocean.

Keywords: 1. Eutrophication – the process by which an ecosystem receives high levels of nutrients (primarily nitrogen and phosphorus) that stimulate excessive plant/phytoplankton growth. When the algae die, they sink to the bottom and are eaten by bacteria, which consume oxygen. If aeration of the water is limited, stratification occurs and hypoxic (low oxygen) or anoxic (no oxygen) zones can form that are stressful or lethal to marine fishes and invertebrates. 2. Hypoxia – oxygen levels too low to support most aquatic life (typically less than 2 mg/l). 3. Phytoplankton – microscopic, photosynthetic marine organisms (primarily single-celled algae). They are what is known as primary producers of the ocean; the organisms that form the base of the food chain. 4. CTD – an instrument used by researchers to monitor the essential physical properties of the ocean including conductivity, temperature, and depth.

Pre-assessment Strategy/Anticipatory Set (Optional): This lesson has students work in groups to discover and evaluate the causes and consequences of eutrophication in the Gulf of Mexico. The aim of the introduction to the lesson is to focus students’ attention on the relevant topics and to identify/dispel any misconceptions. The introduction asks students to think about and discuss topics important for completion of the lesson. The objective is not to provide all the answers (students will do this on their own) but to engage students in the topic. 1. Ask students about how human activity affects the ocean and marine life. Students will likely focus on fishing and other activities done in the ocean itself. Work to have students think about how humans that don’t work or live near the ocean can affect the ocean and marine life. 2. Ask students to brainstorm what physical and chemical properties of the ocean scientists monitor, how they monitor these properties, and why they monitor properties. 3. Ask students to think about factors that would influence where life exists in the ocean and which of these factors are influenced by human activity.

Lesson Procedure: Review/teach the basics of photosynthesis, cellular respiration, and nutrient requirements for living organisms (if necessary). Students should have a fundamental understanding of these processes before beginning the lesson. Students will work in small groups (3-4 students per group) to complete each activity.

Causes of Eutrophication and Hypoxia: 1. Analyze maps of the United States so students can visualize and understand the interconnectedness of the Mississippi River basin and the Gulf of Mexico and how human activities far from the ocean can influence the oceans and marine life. 2. Ask students to think about how human activities can lead to the introduction of excess biological nutrients (nitrogen and phosphorus) into the streams, rivers, and the ocean. Allow students to share the ideas they thought of and lead a brief discussion of these mechanisms. For instance, you may want to discuss: rain washing materials into rivers and into the ocean; direct dumping of waste into the ocean; accidental spills that contain nutrients or contaminants; or release of nutrients into the atmosphere (like gases from factories) that then move into the ocean through dissolution of gases or atmospheric deposition (rain). 3. Ask students to think about how excess nutrients would affect biological productivity (focus on phytoplankton) and how scientists could monitor phytoplankton levels. 4. Provide students with a copy of the “Using Satellite Imagery to Monitor Biological Productivity” worksheet. Tell students that their assignment is to: a. Use NOAA/NASA online data to visualize biological productivity in the ocean and the Gulf of Mexico. b. Read about eutrophication and hypoxia at http://www.gulfhypoxia.net/Overview/. c. Prepare and present a whiteboard with talking points summarizing their findings, which must include data about chlorophyll levels in the ocean and Gulf of Mexico and a step-by-step process explaining how excess nutrients cause eutrophication and hypoxia. 5. Have students present and discuss their results. The following points should emerge during this discussion: a. Satellite imagery shows the presence of higher chlorophyll levels in coastal areas and more polar areas of the ocean. Chlorophyll levels are highest in coastal regions of the northern Gulf of Mexico, with highest levels near the Mississippi River delta. b. The high levels of chlorophyll directly relate to high levels of phytoplankton, which require high levels of nutrients, such as nitrogen, to thrive. Thus, coastal and polar regions have higher levels of biological nutrients needed to support phytoplankton growth. These nutrients typically come from upwelling of deeper and cooler water, which carries with it nutrients from the ocean bottom. c. Hypoxic or dead zones are one result of eutrophication, an ecological imbalance that occurs because of excess nutrients like nitrogen and phosphorus. d. Nitrogen is used by phytoplankton, small, passively drifting marine plants (often microscopic) for reproduction. When there is an excess of nitrogen a period of rapid population growth can occur (known as a plankton bloom). e. When organisms in the plankton bloom die, they sink and are decomposed by bacteria. The decomposition process consumes oxygen and depletes the supply available to other marine life. If aeration is limited, stratification of dissolved oxygen occurs and a hypoxic zone can form on the bottom.

Consequences of Eutrophication and Hypoxia: 1. Ask students to think about and discuss how eutrophication and hypoxia will influence the distribution of marine life and how scientists can study this process. 2. Show a CTD launch and describe how scientists collect and analyze CTD data (http://www.whoi.edu/page.do?pid=8415&tid=3622&cid=1003). 3. Provide students with a copy of the “CTD Monitoring” worksheet. Tell students that their assignment is to: a. Analyze the provided CTD data and answer the questions. b. Create graphs in Excel for CTD data collected from three locations during the Shark Longline Survey aboard the NOAA Ship Oregon II. Use Google Maps to map each location using provided GPS coordinates. c. Predict how and why dissolved oxygen levels would affect the distribution of sharks at each location. d. Analyze longline survey data to determine how dissolved oxygen levels relate to the number of sharks caught. e. Prepare and present a whiteboard with talking points summarizing their findings. 4. Have students present and discuss their results. The following points should emerge during this discussion: a. Hypoxic or anoxic zones will force organisms like fish, crab, shrimp and jellyfish to leave the area in order to survive. Organisms that are mobile are likely to survive but will have to move to a new habitat. Organisms that are immobile or unable to move will die. b. CTD data can be used to assess the presence and distribution of hypoxic zones. c. A large hypoxic zone is present in the northern Gulf of Mexico. d. Few sharks are present in hypoxic zones. No food => no sharks.

What can be done to prevent eutrophication and the formation of hypoxic/dead zones?: Students will be split into groups for a role playing exercise. Groups will be assigned the task of becoming stakeholders in a working group tasked with the job of generating policies to diminish the amount of excess nutrients flowing into the Mississippi River watershed. Students groups will take on roles representing the following stakeholders: 1. Agriculture and Livestock 2. State and Local Resource Management and Development (Urban & Population Related) 3. Fossil Fuel and Industry 4. Commercial and Recreational Fishing 5. Scientific/Environmental/Conservation Groups

Students will be directed to research how their stakeholder contributes to and/or is impacted by excess nutrient runoff and create a proposal for how their stakeholder can help diminish the problem of excess nutrient runoff. Students’ proposals should describe the estimated costs and benefits associated with their specific proposals. This exercise will require students to perform independent research and work as a team to identify the issues that influence their stakeholder and create a plan to address the problem. Groups will then report their findings and work as a class to create an action plan. Students will likely need guidance in their research and resources from the Mississippi River / Gulf of Mexico Hypoxia Task Force will help them focus their work (https://www.epa.gov/ms-htf).

Assessment and Evaluation: Formative assessments of student learning will include evaluation of students’ participation in in-class discussions and evaluation of work analyzing satellite imagery, CTD data, and shark longline survey data. Summative assessment will include evaluation of students’ learning journals that must include: (i) a summary of what they did, (ii) a description of what they learned, and (iii) and a description connecting what they learned with what they already know.

Standards:

• Ocean Literacy Principles Addressed: Ocean literacy is an understanding of the ocean’s influence on you—and your influence on the ocean. An ocean-literate person: • Understands the Essential Principles and Fundamental Concepts about the ocean. • Can communicate about the ocean in a meaningful way. • Is able to make informed and responsible decisions regarding the ocean and its resources.

This lesson will align with the following essential principles of the Ocean Literacy Framework: 1. Earth has one big ocean with many features. 2. The ocean supports a great diversity of life and ecosystems. 3. The ocean and humans are inextricably connected. 4. The ocean is largely unexplored. • State Science Standard(s) Addressed: At the college level, we do not align curriculum with National Science Education standards.

Additional Resources: • Gulf of Mexico Hypoxia Louisiana Universities Marine Consortium -­‐ http://www.gulfhypoxia.net/ • NOAA Hypoxia Viewer -­‐ http://www.ncddc.noaa.gov/website/Hypoxia/viewer.htm • NOAA National Centers for Coastal Ocean Science -­‐ http://coastalscience.noaa.gov/research/pollution/hypoxia/deadzone • NOAA Ocean Observing System -­‐ http://cwcgom.aoml.noaa.gov/cgom/OceanViewer/ • NOAA Environmental Imaging Data -­‐ http://www.nnvl.noaa.gov/view/ • Hypoxia in the Northern Gulf of Mexico 2007 EPA Report -­‐ http://yosemite.epa.gov/sab%5Csabproduct.nsf/C3D2F27094E03F90852573B800601D9 3/$File/EPA-­‐SAB-­‐08-­‐003complete.unsigned.pdf • Scientific Assessment of Hypoxia in Coastal Waters -­‐ https://www.whitehouse.gov/sites/default/files/microsites/ostp/hypoxia-­‐report.pdf • Eutrophication Flash Animation -­‐ http://www.gulfhypoxia.net/Overview/hypoxia_flash.asp • Dead Zone Visualization -­‐ http://www.nnvl.noaa.gov/MediaDetail2.php?MediaID=1062&MediaTypeID=3&Resour ceID=104616 • NOAA Diving Deeper Podcast about Dead Zones -­‐ http://oceanservice.noaa.gov/podcast/supp_july09.html -­‐ deadzone • Environmental Protection Agency Mississippi River / Gulf of Mexico Hypoxia Task Force -­‐ http://www.epa.gov/ms-­‐htf • USGS Nutrients in the Nations Estuaries -­‐ http://water.usgs.gov/nawqa/sparrow/estuary/index.html

Author: Dr. Jeffrey Miller Estrella Mountain Community College 3000 N Dysart Rd Avondale, AZ 85392 [email protected]

Creation date: January 11, 2016

CTD Monitoring Worksheet

Marine life needs dissolved oxygen to live. In 1972, scientists began investigating an oxygen-depleted zone in the northern Gulf of Mexico adjacent to the Mississippi River on the Louisiana/Texas continental shelf, finding severe oxygen depletion at depths of 10-20 meters (approx. 30-60 feet). Many studies since then have revealed dissolved oxygen levels lower than the normal seawater level of about 6 milligrams per liter (mg/L). Hypoxia in the northern Gulf of Mexico is defined as a concentration of dissolved oxygen less than 2 mg/L (2 ppm). This figure is based on observational data that fish and shrimp species normally present on the sea floor are not captured in bottom-dragging trawls at oxygen levels < 2mg/L. When there is no dissolved oxygen, conditions are known as anoxic. As dissolved oxygen drops very low, a dead zone devoid of marine life can form.

Hypoxia occurs naturally in many of the world's marine environments, but their occurrence in shallow coastal and estuarine areas appears to be increasing as a result of human activities. The northern Gulf of Mexico hypoxic zone is the largest human-caused hypoxic zone currently affecting the United States, and the second largest worldwide. The maximum aerial extent of this hypoxic zone measured during the summer of 2002 was approximately the same size as the state of Massachusetts.

What causes hypoxia in the Gulf of Mexico? Major events leading to the formation of hypoxia in the Gulf of Mexico include: 1. Freshwater discharge and nutrient loading of the Mississippi River. 2. Nutrient-enhanced primary production, or eutrophication. 3. Decomposition of biomass by bacteria on the ocean floor. 4. Depletion of oxygen due to stratification.

Figure 1. The Mississippi River Basin: The Mississippi River Basin is divided into six sub-­‐ basins (outlined in color) that flow into the northern Gulf of Mexico. Image credit: Louisiana Universities Marine Consortium; http://www.gulfhypoxia.net/Overview/

The Mississippi River basin drains approximately 41% of the land area of the continental United States and is the dominant source of freshwater and nutrients to the northern Gulf of Mexico. The discharge of the Mississippi River system is controlled so that 30% flows seaward through the Atchafalaya River delta and 70% flows through the Mississippi River delta. About 53% of the Mississippi River delta discharge flows westward onto the Louisiana shelf.

Mississippi River nutrient concentrations and loading to the adjacent continental shelf have greatly changed in the last half of the 20th century. During this time there has been a marked increase in the concentration of nitrogen and phosphorous in the Lower Mississippi River. This increase has been attributed to the increased use of nitrogen and phosphorous fertilizers, nitrogen fixation by leguminous crops (primarily soybeans), and atmospheric deposition of oxidized nitrogen from the combustion of fossil fuels. Many of these nutrients enter the river from non-point sources like runoff, which are much more difficult and complex to control and monitor than point sources of pollution.

Eutrophication follows when ocean systems are over enriched with nutrients beyond natural levels, causing significant increases in primary production, or growth of algae. In the same way that nitrogen and phosphorous fertilize human crops, they also fertilize plants and algae in the ocean. The spring delivery of nutrients initiates a seasonal progression of biological processes that ultimately leads to the depletion of oxygen in the bottom water.

In the northern Gulf of Mexico, eutrophication initiates a massive growth of phytoplankton on the water’s surface. The size of this plankton population is well beyond the natural capacity of predators or consumers to graze it down to a balanced level. Phytoplankton have a relatively short life span, and after dying sink down to the bottom waters and are decomposed by bacteria. Decomposition requires large amounts of dissolved oxygen. The more phytoplankton that bloom, the greater the number of phytoplankton that will die, and the more bacteria will use dissolved oxygen to decompose them. The end result after a bloom is water with little to no oxygen.

Figure 2. Hypoxic zone in the Gulf of Mexico. The green water is enriched in nutrients and sediments from the Mississippi River. Algal blooms from the enriched water create the hypoxic zone. Image credit: Nancy Rabalais, Louisiana Universities Marine Consortium; Southern Regional Water Program.

Stratification of the water column, meaning that environmental factors like temperature and salinity are not uniform from top to bottom, also contributes to the formation of hypoxic zones. Freshwater flowing from the river, and seasonally warmed surface water, has low density and forms a layer above the saltier, cooler and denser water masses near the bottom. This stratification leaves the bottom layer isolated from the surface layer and cut off from a normal resupply of oxygen from the atmosphere. Hypoxic and anoxic conditions can result in massive die-offs of marine invertebrates and fishes and long- lasting dead zones as we’ve seen in the Gulf of Mexico.

Scientists monitor the physical and chemical properties of the oceans to understand how changes in the ocean affect life. For example, scientists use a device called a CTD (for conductivity, temperature, and depth) to monitor the relationships between salinity, temperature, and depth. The shipboard CTD is made up of a set of small probes attached to a large metal rosette wheel. The rosette is lowered on a cable down to the seafloor, and scientists observe the water properties in real time via a cable connecting the CTD to a computer on the ship. Thus, CTDs can provide profiles of chemical and physical parameters through the entire water column. By analyzing these parameters, scientists can make inferences about the occurrence of certain biological processes, such as the growth of algae and presence of low-oxygen (hypoxic) zones. Knowledge obtained from CTD devices can, in turn, lead scientists to a better understanding of such factors as species distribution and abundance in particular areas of the ocean.

Figure 3. Dr. Miller standing with a CTD aboard the NOAA Ship Oregon II in the Gulf of Mexico.

Text adapted from:

Gulf of Mexico Hypoxia: http://www.gulfhypoxia.net/Overview/

NOAA Ocean Explorer: http://oceanexplorer.noaa.gov/facts/ctd.html

Woods Hole Oceanographic Institute: https://www.whoi.edu/instruments/viewInstrument.do?id=1003

NOAA Enrichment in Marine Sciences and Oceanography – The Dead Zone: http://www.st.nmfs.noaa.gov/Assets/Nemo/documents/lessons/Lesson_5/Lesson_5-­‐ Teacher's_Guide.pdf

SERC – The Gulf of Mexico Dead Zone: http://serc.carleton.edu/microbelife/topics/deadzone/index.html Questions: 1. How are hypoxic conditions defined? Anoxic conditions?

2. Figure 4 shows dissolved oxygen content readings from station CB6, which measures at a depth of 19 meters. Use these data to answer the questions a-e: a. Map the position of station C6B. GPS coordinates are W90°29', N28°52'.

b. Which month has the longest period of anoxic conditions?

c. Are there any months during which anoxic or hypoxic conditions don’t exist?

d. Based on the graphs, when are low oxygen conditions (either hypoxic or anoxic) worse: i. Spring (April-June) ii. Summer (July-September) iii. Fall (October-November)

e. Explain why you think the season you chose for (d) is likely to have low oxygen conditions?

f. A significant change in dissolved oxygen occurred between June 17-18. Describe the change and provide a possible explanation for this anomaly.

3. What do you think are some economic impacts that could occur when dead zones occur, not only in the Gulf but in other locations around the world?

4. A shark, a crab and a shrimp find themselves in hypoxic conditions. Who do you think is most likely to survive a dead zone? Why? Figure 4. Bottom Dissolved Oxygen Levels at Station C6B From NOAA Enrichment in Marine Sciences and Oceanography – The Dead Zone: http://www.st.nmfs.noaa.gov/Assets/Nemo/documents/lessons/Lesson_5/Lesson_5-Teacher's_Guide.pdf

Analyzing CTD and Shark Survey Data from the NOAA Longline Shark Survey (NOAA Ship Oregon II, September, 2015)

1. Open the Microsoft Excel File “CTD Data” 2. Graph Oxygen levels (mg/L) versus Depth (m) and determine the location for the following stations in the northern Gulf of Mexico: a. Station 1065 b. Station 1146 c. Station 1227

3. Describe how oxygen levels change with increasing depth at each station.

4. What may account for any differences in oxygen levels at the surface versus at the bottom?

5. How do you think observed differences in oxygen levels would affect the distribution of marine life at each location?

6. Determine the number of sharks/fishes caught at each station.

a. Station 1065:

b. Station 1146:

c. Station 1227:

7. Analyze data for shark/fish numbers together with CTD data for dissolved oxygen levels. What conclusions can be made regarding the effect of oxygen levels on the distribution of sharks and fishes?

CTD Data:

https://teacheratsea.files.wordpress.com/2017/03/jeff-

miller-ctd-data-for-science-lesson.xlsx

Using Satellite Imagery to Monitor Biological Productivity

Chlorophyll Levels in the Ocean

1. Go to the NOAA View Data Explorer at https://www.nnvl.noaa.gov/view/globaldata.html Click here to close welcome window

2. Close the Welcome window. 3. Click on “Add Data” 4. Click on “Ocean” 5. Click on “Life” 6. Click on “Chlorophyll”

7. Click on “Yearly” to visualize chlorophyll concentrations for the previous year.

You can double click on the map to zoom in to a specific region of the world.

Questions:

Describe the pattern of chlorophyll levels you observe in the ocean. Use the following questions to guide your work: 1. What organisms are being examined by visualizing chlorophyll levels in the oceans? 2. Are chlorophyll levels uniform throughout the ocean? 3. Are chlorophyll levels typically higher in coastal waters or the open ocean? 4. Are chlorophyll levels typically higher in warmer, equatorial/tropical waters or in colder, polar waters? 5. What do you think accounts for the differences in chlorophyll levels seen in different parts of the ocean?

Evaluate some possible reasons to explain differences in chlorophyll levels by analyzing various chemical properties of the ocean.

Click on “Back” then “Chemistry” to visualize various chemical properties of the ocean.

Describe how dissolved nitrate and oxygen at 0 meters (yearly) relates to chlorophyll levels. Chlorophyll levels in the Gulf of Mexico

Go to http://cwcgom.aoml.noaa.gov/cgom/OceanViewer/

Click on “Regional Ocean Color” and select “Concentration of chlorophyll in sea water”.

Change the date to “June 5, 2015”.

Zoom in and reposition the map to view the Gulf of Mexico.

Click here to zoom

Click and drag to reposition the map

Describe the pattern of chlorophyll levels you observe in the Gulf of Mexico. Use the following questions to guide your work: 1. Are chlorophyll levels uniform throughout the Gulf of Mexico? 2. Are chlorophyll levels typically higher in coastal waters or the open Gulf? 3. What region of the Gulf of Mexico has the highest levels of chlorophyll? 4. Why do you think this region has such high levels of chlorophyll compared to other regions of the Gulf of Mexico?