Algae in the Wekiva River: Is It Helping or Hurting Water Quality?
I have lived in Florida all my life, and I have always been able to enjoy having the Wekiva River right across the street from my neighborhood. My family has a boat docked there, so we can enjoy the peaceful river anytime we want to. I go canoeing and fishing, but never once had the thought crossed my mind that the river might be polluted. I was blissfully unaware that something could be harming the river's ecosystem. In August 2006, I was shocked by a headline in the Orlando Sentinel. When I read the headline "Algae Threaten Wekiva," reality hit me, and I began to realize that the river that I had always known might not be as clean and healthy as I thought it was. Right away, I knew that I would want to research this topic further and hopefully find out if the algae I read about really do have an effect on the Wekiva River's water quality.
I learned many things from the article in the Orlando Sentinel. One thing I learned is that filamentous algae, which grow in clumps or mats, can crowd aquatic plants and creatures. In addition, this article also stated that the "killer algae" were disturbing the aquatic plants and the bottom-dwelling creatures, fish, and birds that have their habitat in the Wekiva River (Spear, 2006). I based my first hypothesis on this information. I hypothesized that if I tested the Wekiva River for killer algae, then the areas with higher algae levels would have fewer plants and animals. I wanted to be able to answer the following questions after I had completed my observations: Are plants and animals losing their habitats to the algae? Are the algae killing off plant and animal life?
I then began to research how I could accomplish this. I was bombarded with questions such as: How do I take water samples? What supplies will I need, and how will I obtain these things? How can I tell what type of algae are in my sample? Surprisingly, the Internet was not a big help. I was unable to find any instructions on how to take proper water samples, or even what equipment is needed to do this. Though I did find a LaMotte water sampler for sale, I still did not know what to do with the sample after I took it.
Seeing that the information I found on the Internet did not answer any of the questions I had regarding how to go about completing my observations, I started to look to other sources for help. I wanted to ask someone how to take water samples, and if there was a lab where I could send the samples to be analyzed to determine what type of algae were present and how much was in the river. My first thought was to go to the Wekiva Springs State Park and talk to a ranger. When I did this, she did not know anything pertaining to my project, but she gave me the phone number of a biologist. I contacted him, but he was not able to help me, either. From there, I went online and got the e-mail address of Aisa Ceric. She forwarded my e-mail to many different people, and it finally ended up with Deborah Shelley, the manager of the Wekiva/Middle St. Johns/Tomoka Marsh Aquatic Preserves. I continued to communicate with her, but I did not obtain any relevant information. Then my dad put me in touch with Leila Nodarse and Debra Harrington from Nodarse and Associates. I had an appointment to meet with Debra, a geotechnical engineer, but instead she directed me to meet with Marcia Anderson.
Marcia Anderson works at the Orange County Environmental Protection division. I learned so much after meeting with her. After Marcia looked at my hypothesis, she gave me suggestions on how I could make it more detailed and exact. Instead of "animals," I would be looking at macroinvertebrates. She explained to me how to take samples of water and how to collect macroinvertebrates. Marcia also taught me how I was supposed to take my samples. Near the end of our two-hour meeting, she showed me maps of the Wekiva and gave me suggestions on where my possible sample spots could be. Just before I left, Marcia gave me four large collection jars and a tray for observing the macroinvertebrates, six small collection jars for the water (algae) samples, a dip net, a thermometer, charts and booklets to identify the plants and macroinvertebrates that I run into on my observations, and a cooler, which I will use to keep the water samples cold. I will then take my algae samples back to her, and we would look at them under a microscope.
After meeting with Marcia, I rethought my hypothesis. My new hypothesis was: If I go to three different locations along the Wekiva River and take algae samples at each location, then the areas with a smaller and less toxic algae population will have more of the macroinvertebrates that indicate good water quality. I would also be trying to answer the question, Will the types of benthic macroinvertebrates present prove that the algae in the Wekiva River are affecting the quality of the water?
I would now be observing benthic macroinvertebrates, although at first I was not even sure what a benthic macroinvertebrate was. Dictionary.com says that benthic is an adjective and means, "of or relating to or happening on the bottom under a body of water." Streamnet.org says that macroinvertebrates are "invertebrates visible to the naked eye, such as insect larvae and crayfish." Benthic macroinvertebrates are water-quality indicators. I would use the Pollution Tolerance Index (PTI) to determine if the water quality is excellent, good, fair, or poor based on the types of macroinvertebrates I found (Anderson, 2007).
It was now time to make my observations! I arrived at the Wekiva River at 9:10 a.m. It was very sunny and around 21°C. There was a faint breeze blowing continually instead of in gusts. Birds were flying overhead and nesting in trees, and the water was very still and calm. My first sample was taken from a canoe. As I was paddling to my first spot, I noticed that the depth of the river was greatly varied. It had gone to chest-high from ankle-deep in a matter of a few feet.
|Sample 1||Sample 2||Sample 3|
When I arrived at my first sample spot (I decided this spot would be about a quarter-mile away from the springs; it was 10:40 a.m.), the water temperature was 23°C and about 25 centimeters deep. I collected my first algae sample in one of the jars and then used the dip net to collect macroinvertebrates from the water. I put this sample in the bigger jar and from there into the tray. I began to identify and count the macroinvertebrates. I counted 12 shrimp, 17 scuds, one beetle, and one snail. After I counted everything, I poured the tray back into the water. The sample contained a lot of vegetation. Across from where our boat was docked, there was an abundance of plants in the water; I identified these as spatterdocks. They are heart-shaped and have long, thick, underwater stems (Plant Identification Chart, 1994). There was a lot of eelgrass under the water. The only other type of vegetation I could find was common duckweed (Plant Identification Chart, 1994).
The Wekiva Marina was my second sample spot. The air temperature was 26°C; the water temperature was 23°C. The water was one meter deep. I took my second algae sample in front of the marina. There were many spatterdocks, and there was also common duckweed. The water was not clear here, so I could not tell if there was any eelgrass under the water. This macroinvertebrate sample had much less vegetation and much more gravel, and again I put this sample back into the water.
I chose Shell Island at the First Flats to be my third and final sample spot. It is about a half-mile from the marina. The air was not as hot as it was before. The water temperature was 22°C and the water was 50 centimeters deep. On both sides of the First Flats there was a sea of spatterdocks and lots of eelgrass in the water. Occasionally some water lettuce could be seen. I took the algae sample, and the macroinvertebrate sample contained a lot of sand. Along with the living invertebrates, there were also parts of a clam shell and a mussel shell. These were my last samples taken.
Using the PTI, the biotic index of water quality at my first sample spot (a quarter mile away from the springs) was 7, which indicates poor water quality. The marina was given an 18, which means the water quality is good. Shell Island's index of water quality was 12, resulting in fair water quality.
Now I had to find out if the types of algae in the water have anything to do with the water quality at these three places. After I looked at the algae under a microscope, Marcia helped me to identify the different types. My first algae sample had 280 diatoms per sample, 80 cyanophyceae, and 120 clorophyceae per sample. My second sample had 120 diatoms and 40 cyanophyceae per sample. Lastly, my third sample had 120 diatoms and 120 cyanophyceae per sample. Cyanophyceae is a type of blue-green algae. Blue-green algae can sometimes bloom and produce toxins (Cyanophyceae, 2007). Diatoms may also be toxic (Pond Solutions.com).
In conclusion, the Wekiva Marina (Sample 2) had the best water quality, followed by Shell Island (Sample 3). The area with the poorest water quality was the site about a quarter-mile away from the springs (Sample 1); it had the most diatoms per sample, and the greatest amount of total algae. The Wekiva Marina had the least amount of algae and the best water quality when comparing my three samples. Shell Island had a moderate amount of algae and moderate water quality. Therefore, I concluded that the amount of algae in the Wekiva River does relate to water quality. I proved my hypothesis correct, for the areas with a smaller algae population did have better water quality. I plan on studying this topic further and possibly observing different areas of the river. By completing my observations and exploring my surroundings, I now know that the majority of the Wekiva River is clean and healthy!
|Sample Site||Algae||Water Quality|
Sample Site 1|
-¼mile from Springs
Sample Site 2|
Sample Site 3|
Anderson, Marcia. Interviewed by Ashley Hunt. Orlando, Florida, 5 January 2007.
Benthic. Dictionary.com. Retrieved from the World Wide Web on 10 January 2007. http://dictionary.reference.com/browse/benthic.
Benthic Macroinvertebrates in Our Waters. Environmental Protection Agency. Retrieved from the World Wide Web on 10 January 2007. http://epa.gov/bioindicators/html/benthosclean.html.
Blue Green Algae, Filamentous Algae, Pond Algae, Horsehair Algae, Toxic Algae, Algae Diatoms, Green Algae, Brown Algae, Pond Moss, Pond Scum. Pond Solutions.com. Retrieved from the World Wide Web on 4 March 2007. http://www.pondsolutions.com/blue-green-algae.htm.
Cyanophyceae. The Free Dictionary by Farlex. Retrieved from the World Wide Web on 21 January 2007. http://www.thefreedictionary.com/Cyanophyceae.
Freshwater Benthic Macroinvertebrates. Maryland Department of Natural Resources. Retrieved from the World Wide Web on 10 January 2007. http://www.wpa.gov/bioindicators/html/benthosclean.html.
Glossary of Terms. Streamnet. Retrieved from the World Wide Web on 10 January 2007. http://streamnet.org/pub-ed/ff/Glossary/index.html.
LaMotte. LaMotte. Retrieved from the World Wide Web on 12 December 2006. http://lamotte.com/pages/edu/1077.html.
Plant Identification Chart. Florida Aquatic Plant Management Society, Inc. 1994.
Pollution Tolerance Index (PTI). Roaring Fork Conservancy. Retrieved from the World Wide Web on 4 March 2007. http://www.roaringfork.org.
Spear, Kevin. "Algae Threaten Wekiva." Orlando Sentinel August 2006: A1.
Toxic Algal Blooms—A Sign of Rivers Under Stress. Nova. Retrieved from the World Wide Web on 21 January 2007. http://www.science.org.au/nova/017/017key.htm.
Watershed Facts. St. Johns River Water Management District. Retrieved from the World Wide Web on 20 January 20 2007. http://www.sjrwmd.com/archydro/contact.html.
More About This Resource...
This winning entry in the Museum's Young Naturalist Awards 2007 is from a Florida 7th grader. Ashley investigated if algae was helping or hurting the water quality of a river near her home. Her essay includes:
- an overview of how she became interested in the health of the Wekiva River;
- her research into filamentous algae and the help she received from a biologist in structuring her experiment to observe benthic macroinvertebrates; and
- details of her observations, including her conclusion that algae in the Wekiva River does relate to water quality.
Supplement a study of biology with an activity drawn from this winning student essay.
- Ask students to create a class list of things that can decrease the water quality of a river. Are there any organisms on their list?
- Send students to this online article, or print copies of the essay for them to read.
- Have them write a one-page reaction to the essay, focusing on what they learned about how organisms can have a negative impact on water quality.
OriginYoung Naturalist Awards