Student Activity

Overview
Human civilization has flourished around major rivers and coastal areas for obvious reasons. It is estimated that as of 1998 more than a half of the world population lives and works within 200 kilometers of a coastline (Hinrichsen, Don. Coastal Waters of the World: Trends, Threats, and Strategies. Washington D.C. Island Press, 1998.) It is this growth in human activity that provides significant changes in the land surrounding our waterways. With a catastrophic weather event such as a hurricane or a long period of sustained rainfall, the results of increased erosion have short term and long ranging effects on the coastal biological communities. Sediments flowing into the coastal waters carry chemicals from the land that may accumulate in the tissues of aquatic organisms. Nutrient levels fluctuate as a result of agricultural run-off that may, in turn, cause variations in coastal productivity. Oxygen levels drop significantly in bottom waters as decomposition of the organic material occurs during months of little water column mixing. A heavy increase in sand, silt and clay alter the bottom topography and local habitats, thus resulting in a change in the diversity and distribution of coastal marine species. The problems of coastal management become increasingly more complex as we view the effects of human influence directly from specific sensors carried on the satellites.

Goals
You will:

• learn how to read satellite imagery using reflectivity and Sea surface temperature for detection and monitoring of sediment plumes in a large embayment such as the Gulf of Mexico.
• use satellite maps to monitor real time vapor imagery from GOES satellites and satellite-derived precipitation estimates.
• use ocean color satellite views to examine coastal areas of high productivity.
• investigate the correlation between effluent and concentrations of Mercury in fish and invertebrate samples taken from the Mississippi delta region prior to and after the floods of 1993.
• predict locations and conditions that would place a coastal area at risk of experiencing high rates of run-off and the associated problems of nutrient overloading and increased turbidity.

Explanation of Questions
This lesson is designed to help you create a hypothesis, research it, and make a conclusion about HAB's. You can do this by using the NOAA/NESDIS website to help you find data for research. Your teacher will help to guide you in the appropriate direction by helping your group create a valid hypothesis, discover the best methods to research your hypothesis, and show you ways to find appropriate data to support your hypothesis. This lesson will give you a few examples of questions and supporting data so that you can come up with questions and supporting data of your own.

 

1. Students examine images of sediment plumes in different parts of the world and with different events.
   
   
   1. Open the following link : http://www.osei.noaa.gov/OSEIiod.html
      
      
   2. To view files of sediments from the Yangtze River in China, click under OCEAN (from the sidebar, and then select 2001 from the archives available.
      
      Download files for several different parts of the world and compare the visible sediment plumes that extend into the coastal waters from flooding events. Go to the sidebar and select FLOODS, select from the menu and then the year of the archived event. The United States ( Mid-Atlantic file has many excellent satellite images of the impact from Hurricane Floyd).
      
      How does the flooding event in Peru in 1998 differ from the flooding event of the Yangtze River in China in 1998 (look at the photo ) ?
      
      What factors influence the amount and extent of erosional products that end up in our coastal waters?
      
      
2. Students examine historical satellite data from the Flood of 1993 to visualize the impact of increased river outflow in the Gulf of Mexico. Using rainfall model indicators, students compare events to predict areas of the United States that could experience high rates of coastal turbidity.
   
   
   1. Rainfall rates are calculated from satellites data providing the public awareness of pending flood conditions. Use the following link to examine estimated precipitation rates and satellite imagery for your state. The page provides daily information and an archive of data for monitoring excessive rainfall to a region in the United States.
      http://orbit35i.nesdis.noaa.gov/arad/ht/ff/auto.html
      
      As an example, compare the 24 hour rainfall rates for Hurricane Lili that impacted the Western Gulf of Mexico during the first week of October, 2002.
      ftp://orbit35i.nesdis.noaa.gov/pub/arad/ht/f_f/auto/24hour/24hour02/
      
      What impact did the excessive precipitation have on the delta for the Mississippi River and the associated coastal waters? What changes in the coastal waters could be measured with an influx of run-off products into the embayment?
      
      
   2. Visit a local weather station data records at the link below to graphically compare precipitation totals by year or month. Use the map to locate at data collecting station in a coastal region such as the Gulf of Mexico ( try New Orleans, La). Make predictions from the historical data about events that could trigger an increase in river outflow products.
      http://gis.ncdc.noaa.gov/website/hofn/gsn2/viewer.htm
      
      
   3. The Gulf of Mexico is a well studied region as it receives sediments and other run-off products from the Great Mississippi River, the Rio Grande, and several other large rivers. Satellites use several indicators to measure the change in dissolved solids in the coastal waters. Changes in Sea surface Temperatures may be an indicator of a large volume of water entering the embayment area. If the water carries sediments, the discharge area may see an increase in SST as these particles absorb light. During the Mississippi River Flood of 1993, near-record and record precipitation in June and July fell on already saturated soil. From January to July of 1993, this river basin area received between 20 and 40 inches of total precipitation. (http://water.usgs.gov/nwsum/WSP2425/flood.html). Examine the anomalies in SST for the Gulf of Mexico in the late summer to early autumn of 1993 from the following link: http://www.osdpd.noaa.gov/PSB/EPS/SST/al_climo.html
      
      How does SST relate to rainfall events?
      
      Reflectivity images derived from a visible band on the AVHRR sensor provide a general indicator of turbidity in the coastal waters. Use the link below to compare the composite monthly reflectivity and SST in the peak months (June to August) of outflow from the Great Flood of 1993:
      http://www.csc.noaa.gov/products/gulfmex/html/sst_ser.htm
      http://www.csc.noaa.gov/products/gulfmex/html/refl_ser.htm
      
      What happens to the reflectivity during the periods of increased rainfall?
      What types of suspended and dissolved particles could be contributing an area of higher turbidity?
      
      
3. Students examine the possible outcomes of increased sediments in the coastal waters.
   
   
   1. An increase in run-off as visualized by sediment plumes, reflectivity data and other satellite imagery may bring more nutrients into the coastal zone. Chlorophyll amounts from increased phytoplankton growth can be measured using satellite imagery. Compare the seasonal change in chlorophyll in the coastal waters at the mouth of the Mississippi using the below link: http://wwwo2c.nesdis.noaa.gov/ocolor/color_browse_open_2.htm
      
      Select your region as the Gulf of Mexico.
      
      Select time frame: Compare several data sets: January, March, June, September 2002.
      
      Besides seasonal changes in chlorophyll amounts, what other factors could contribute to higher productivity along the coast?
      
      
   2. Concentrations of industrial chemicals may also increase in the coastal waters with an increase in sediment load. The tissues of many marine organisms may accumulate residues of these chemicals. Examine the data from the Gulf of Mexico using this link:
      http://www.gomoos.org/chameleon/gulfwatch/
      
      Use this interactive data mapper to select site averages by year for Mercury. On the map, select Graph from across the top, and then create a bar graph for the year 1993. Compare graphs for two different years such as 1991 and 1993.
      
      What organisms that live in the Gulf of Mexico seem to have the highest values of accumulated Mercury in their tissues? Is there a correlation between the amounts of mercury and the increased products from the rivers due to excessive run-off?

Additional Questions to think about

1. The Gulf of Mexico issues of hypoxia and pollution are well recognized. What combination of factors could cause other coastal areas to develop similar problems?
   
   
2. Using a map of the world, identify coastal areas that are or could be experiencing issues that result from increased effluent.

Continue to the Coastal Waters Investigation