Our Backyard Waterways: Predicting a Phytoplankton Bloom

When is Dinner Served? Predicting the Spring Phytoplankton Bloom in the Gulf of Mexico University of New Hampshire Coastal Observing Center Institute for the Study of Earth, Oceans, and Space

©MathScience Innovation Center When is Dinner Served? Users will produce and analyze graphs showing water temperature, salinity, density, and chlorophyll concentration for 2004 at four buoy locations in the Gulf of Maine. Time required: About three 45 minute classes

©MathScience Innovation Center Goals Explain the ecological importance of phytoplankton Explain the ecological importance of phytoplankton Describe the components that influence a phytoplankton bloom Describe the components that influence a phytoplankton bloom Interpret satellite images in order to correlate buoy data Interpret satellite images in order to correlate buoy data Use the scientific process to predict the onset of the spring bloom based on background data Use the scientific process to predict the onset of the spring bloom based on background data Download and analyze graphs of oceanographic buoy data Download and analyze graphs of oceanographic buoy data Identify geographic features in the Gulf of Maine Identify geographic features in the Gulf of Maine

©MathScience Innovation Center Case Study Phytoplankton are a main food source in the ocean. Sustain almost all life in the ocean. Microscopic plants Produce more than half of Earth’s Oxygen supply!

©MathScience Innovation Center Case Study All plants need sunlight, carbon dioxide, water, and nutrients to grow. Sunlight most available at the water surface. Chlorophyll-a makes them green. Green blooms can be detected in satellite images.

©MathScience Innovation Center Case Study Blooms attract the attention of scientists and fisheries. Global Carbon Cycle: large consumer of carbon dioxide, therefore if reduced it could affect our global climate. Limiting growth factors: amount of sunlight and nutrients (nitrate, phosphate, and silicate) Nutrients found in deeper cold waters are brought to the surface in upwellings in the spring.

©MathScience Innovation Center What causes a bloom? Blooms occur when sunlight and nutrients are readily available to the plants, and they grow and reproduce to a point where they are so dense that their presence changes the color of the water in which they live.

©MathScience Innovation Center North Atlantic bloom Movie

©MathScience Innovation Center What causes a bloom? May last a few days to several weeks May be small or cover hundreds of square kilometers. Scientists have not yet been able to predict the exact date and location of a phytoplankton bloom before it occurs, but through the use of satellites, long term moored buoys and monthly oceanographic research cruises we are able to make better educated guesses.

©MathScience Innovation Center Gulf of Maine Scientists study phytoplankton using research vessels, long term moored buoys, and satellite instruments Depth and Shape of the ocean floor determines upwellings

©MathScience Innovation Center Gulf of Maine Georges Bank and Browns Bank are just two of the large underwater ledges that create a barrier between waters off shore and the inner Gulf of Maine.

©MathScience Innovation Center Gulf of Maine Water generally flows in a counterclockwise direction.

©MathScience Innovation Center Gulf of Maine Cold water from the north, known as the Labrador Current, and warm water from the south, known as the Gulf Stream, are mixed outside the Gulf before entering. The combination of these consistent currents, the direction of flow, the bathymetry and much more, makes the physical structure of the water column very different at each buoy location.

©MathScience Innovation Center Stratification Temperature, salinity, and density affect the water column. As salinity increases, density also increases. At temperature increases, density decreases. SalinityTemp.

©MathScience Innovation Center Stratification When ocean water becomes separated into layers of similar densities, it is said to be stratified. The black line also represents the temperature within the layer.

©MathScience Innovation Center Nutrients Concentrations of nutrients in the water column vary depending on the time of year, density of water, how they entered the ocean, and how much mixing has taken place during that season. Nutrient data is collected from water samples gathered on research vessels

Nutrients Change with the seasons In general, when nutrients are found near the surface, they are not plentiful at deeper levels and vice versa. Winter mixing brings nutrients up from below, concentrating them near the surface. Spring warming creates a surface layer that floats on top, halting the supply of nutrients brought to the surface. As spring turns to summer, nutrients in the surface layer are consumed by phytoplankton, reducing nutrient availability at the surface.

Nutrients As summer sets in, phytoplankton die and drift to the bottom, taking the nutrients they ingested with them. Surface waters are now left with few nutrients available. Once autumn sets in with cooler days, a limited amount of vertical mixing brings nutrients up from below. In winter, heavy winds and plummeting temperatures cause strong mixing again.

Blooms Spring brings warmer temperatures and increased sunlight, creating a thermocline that traps nutrients at the ocean surface. This allows phytoplankton to absorb energy and take in the nutrients they need to photosynthesize and multiply. As the phytoplankton use up the available nutrients however, they begin to die and drift to the bottom.

Norway Bloom 2003

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GoMOOS Buoys Gulf of Maine Ocean Observing System Gulf of Maine Ocean Observing System 10 buoys in the Gulf of Maine with real-time data available 10 buoys in the Gulf of Maine with real-time data available Maintains 11 more buoys Maintains 11 more buoys

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Compare Buoy Data

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Graphing & Data Downloads

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Graphs Create a graph of the following data: Create a graph of the following data: Density Daily Avg. 1/1/04 – 12/31/04 Buoy B Salinity Daily Avg. 1/1/04 – 12/31/04 Buoy B

©MathScience Innovation Center Predicting a Bloom Create Graphs for Buoy E, I, M Water Temperature Salinity Density Buoy M only select these locations 1 m, 2 m, 20 m, and 50 m 12 graphs total

©MathScience Innovation Center Predicting a Bloom Step 1: Step 1: Group graphs by Buoy location

©MathScience Innovation Center Step 2: Analyze graphs to predict Spring Bloom How does depth affect the water temperature, density, and salinity? What do your density graphs look like during times that the water column is mixed? How do the lines on the density graph change as the water becomes stratified? Predicting a Bloom

©MathScience Innovation Center Predicting a Bloom Knowing that blooms occur when phytoplankton have ready access to sunlight and nutrients in a floating surface layer, make a prediction of the month or week that a bloom might occur for each buoy location. Does your predicted bloom date vary by buoy location? Consider where each buoy is located in the Gulf. Can you explain any difference in predicted bloom dates based on the buoy locations?

©MathScience Innovation Center Chlorophyll Data Step 3: Checking your prediction Use GoMoos to graph data from Buoy B, E, I, and M Chlorophyll / Daily Avg. 1/01/2004 – 12/31/2004 How can you use this data to predict a bloom? Spikes in the graph indicate high levels of chlorophyll, and are good indicators of high levels of phytoplankton.

©MathScience Innovation Center Chlorophyll Data How do the levels of chlorophyll compare at each Buoy location? How do the levels of chlorophyll compare at each Buoy location?

©MathScience Innovation Center Buoy M appears to have about 15 times as much chlorophyll as the other locations. Ocean buoys are subject to many factors that can alter data collection: boats accidentally running into buoy, storms, whales… Also notice that after May 15 the buoy stopped recording all data, which may suggest it was taken off-line for repairs! Therefore, we should disregard data from this buoy. Chlorophyll Data

©MathScience Innovation Center Using Satellite Images March 22, 2003April 23, 2003

©MathScience Innovation Center WebCoast Images University of New Hampshire: Center for Excellence in Coastal Ocean Observations and Analysis University of New Hampshire: Center for Excellence in Coastal Ocean Observations and Analysis Look in the middle column under Satellite Images: Search and Retrieval Tool Look in the middle column under Satellite Images: Search and Retrieval Tool

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When is the bloom? April 22, 2004

©MathScience Innovation Center What about Buoy M? Evidence shown here suggest that Buoy M only reads 2-5 mg chlor-a per cubic meter, and is not at the highest location of phytoplankton density.