Abstract
Harmful algal blooms occur when algae, which form the base of the ocean food web, grow in massive numbers and produce toxic or harmful effects on people, fish, shellfish, marine mammals, and birds. In this project you will learn how to use archived data from continuous monitoring stations on the Chesapeake Bay to study how water quality measurements (dissolved oxygen (DO), salinity, temperature, pH, turbidity, and total chlorophyll) change before, during, and after harmful algal blooms.Objective
The goal of this project is to use online data from continuous monitoring stations on the Chesapeake Bay to study water quality measurements before and after algal bloom events.
Introduction
Have you read articles in the newspapers about dead fish found on a beach, or watched a TV news report informing the public of closed beaches due to water discoloration? These may be signs of harmful algal blooms (HABs). HABs occur when algae, which live in the sea and form the base of the food web, produce toxic or harmful effects on people, fish, shellfish, marine mammals, and birds. HABs have been reported in almost every U.S. coastal state. The frequency, extent, and severity of HAB events appear to be increasing. HABs are indicators of the health of ecosystems and are of national concern. Many coastal areas suffer from HAB events each year, threatening coastal ecosystems, local and regional economies, and endangering human health.
The Maryland Department of Natural Resources has a series of continuous monitoring stations that report water quality data for locations in and around the Chesapeake Bay. The stations measure: dissolved oxygen (DO), salinity, temperature, pH, turbidity, and total chlorophyll (details in table, below). You can view and print graphs of archived data from their website. The numerical data is also available for download. In this project, you will look for relationships between the water quality variables and learn how they are used to analyze HABs.
| Description of Continuous Monitoring Data | ||
| Data | Units | Description |
| Dissolved Oxygen (DO) Concentration | mg/l | Since most aquatic organisms such as shellfish and other living resources require oxygen to survive, this is a very important measure of water quality. DO concentrations below 5 mg/l can stress organisms. DO concentrations of around 1 mg/l can result in fish kills. |
| DO Percent Saturation | % normal maximum | DO saturation percent shows the level of dissolved oxygen as a percentage of the normal maximum amount of DO that will dissolve in water. Colder water can hold more DO than warmer water. Super-saturation (over 100% DO saturation) can occur when there is a large algal bloom. During the daylight, when the algae are photosynthesizing, they can produce oxygen so rapidly that it is not able to escape into the atmosphere, thus leading to short-term saturation levels of greater than 100%. |
| Salinity | ppt (parts per thousand) | Salinity in the Bay and its tributaries comes from the ocean. Therefore, areas closer to the ocean have higher salinities. During periods of low precipitation and river flow, salinity increases as it intrudes further up the Bay and its tributaries, while during wetter periods, salinity decreases. Salinity cycles related to the tides may also be evident in these graphs as salinity increases during flood tides and decreases during ebb tides. Salinity levels are important to aquatic organisms, as some organisms are adapted to live only in brackish or salt water, while others require fresh water. If the salinity levels get too high, the health of freshwater fish as well as grasses in the river can be affected. |
| Water Temperature | °F | Water temperature is another variable affecting suitability of the waterway for aquatic organisms. If water temperatures are consistently higher or lower than average, organisms can be stressed and may even have to relocate to areas with a more suitable water temperature. Water temperature directly affects the solubility of oxygen (see DO Concentration, above). Water temperature is a product of warming from the sun and air temperature. |
| pH (Acidity) | pH | pH measures the acidity of the water. A neutral pH is 7. Lower numbers indicate higher acidity, while higher numbers indicate more alkaline conditions. pH can be affected by salinity (higher salinities tend to buffer pH in the 7-8 range) and algal blooms (large algal blooms can raise the pH over 8 in low-salinity waters). |
| Turbidity | NTU | Turbidity is a measure of water clarity. Events that stir up sediment or cause runoff such as storms will increase the turbidity of the water. Dense algae blooms will also lead to higher turbidities. Relatively clear water (low turbidity) is required for the growth and survival of Bay grasses. |
| Chlorophyll Concentration | μg/l | Chlorophyll concentration is a measure of the amount of algae in the water. Chlorophyll is the main chemical responsible for photosynthesis in plants, the process by which sunlight is converted into food energy. Values over 100 μg/l are considered to be a severe bloom. The chlorophyll concentrations we present are calculated from fluorescence values. At this time, blue-green algae such as Microcystis fluoresce outside the range of our probes. Therefore, blue-green algae blooms are not likely to show significant chlorophyll concentrations. |
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to understand the following terms and concepts:
Questions
Bibliography
Materials and Equipment
To do this experiment you will need the following materials and equipment:
Experimental Procedure
This will guide you around the Maryland's Department of Natural Resources (MDNR) website, familiarizing yourself with the data and how to read it. Once you have a feel for things you can ask your own question, find information here or look at some of the other data sets that will help to answer questions along other coastlines.Online Data: Navigating the Maryland DNR Chesapeake Bay Continuous Monitoring Website
| Matrix for Analyzing Relationships Between Water Quality Variables | ||||||
| DO Concentration | DO Saturation | Salinity | Temperature | pH | Turbidity | |
| Total Chlorophyll change (increase, decrease, no effect/unrelated) | ||||||
| Hypothesis and Rationale | ||||||
A Harmful Algal Bloom Example
Ideas for Projects
Variations
Here are some questions to get you thinking about possible variations of this project:
Credits
By Beth Jewell, Einstein Distinguished Fellow, Office of Education, NOAA
Edited by Andrew Olson, Ph.D., Science Buddies
Sources
Last edit date: 2006-08-15 17:09:46
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