THE WATAAH CHESTNUT! (Water Chestnut) ((​
Trapa natans​
)) Adam Levine, Chad Halson, Jonayed Ahmed, Maisha Ahmed, Michelle Tebolt Arlington High School Introduction: The first data set we analyzed is found on the Cary Institute Website. The data samples were taken from the freshwater tidal section of the Hudson River. It was published in "Vascular Plants as Engineers of Oxygen in Aquatic Systems" by Nina Caraco, Jonathan Cole, Stuart Findlay, and Cathleen Wigand in ​
Bioscience​
(2006) 56(3): 219­225. The data presented on the graph was collected on June 29, 2003. We then used a second source of data to confirm our hypothesis that the dips in the dissolved oxygen levels were during low tides of the day. This additional data was taken from the Hudson River, New York Tide Chart on the website tides.mobilegeographics.com. This data table presents the Hudson River tide schedule on June 29, 2003. Data Comparison: When analyzing figure 1 and figure 2 we noticed the changes in D.O. (dissolved oxygen) levels between the three compared aquatic habitats: a habitat with water chestnuts, a plain river channel, and a habitat with water celery. The river channel trend line serves as a control or normative in the research. Our second source of data in figure 3 shows the tide schedule. It served as a comparison with our first data chart, in order to examine our hypothesis that the dips in D.O. levels matched the impact of the tidal change. Low tide was at a 10:22 AM and 10:11 PM (22:11) while high tide was a little after 3:21 AM and 4:03 PM (16:03). Both the water celery and water chestnuts show trends that show a decrease and increase of D.O. percentages that visually seem to correlate with the outgoing and incoming tides; however when we calculated the rate of change of D.O. percentage per hour the water celery during the first high to low tide showed a positive increase with a rate of approximately 3.6 while the water chestnut during that same time period had a negative decrease with a rate of change of about ­9.0. During the second change in high to low tide water celery had change in rate of ­2.4 while the water chestnut had a drastic change of rate of ­10.1 (figure 4). These figures confirm that water chestnuts in the Hudson River have a greater impact on the D.O. levels at high and low tides than compared to the water celery. Graphs / Data: Figure 1: Figure 2: Figure 3: Figure 4: Data Interpretation: Based on the data collected in the Hudson River the dissolved oxygen (D.O.) levels are lower in areas of water chestnuts than compared to D.O. levels in areas of water celery and the river channel. The data we analyzed shows a relationship between D.O. levels and the tide. This relationship can be explained in that rising tides bring oxygen rich waters from the main stem of the river, which results in higher D.O. levels. Receding tides lead to low D.O. levels as water chestnuts remove oxygen from the decreased volume of water in the river that is less saturated with oxygen, causing a significant impact on the D.O. levels. Since the water chestnut grows in a dense bed, it dramatically decreases the amount of sunlight reaching the water below. With less sunlight available, plants such as algae, phytoplankton, and submerged aquatic vegetation like water celery, are unable to grow and release oxygen into the water from photosynthesis. The water chestnut leaves float on top of the water, so they release oxygen into the atmosphere rather than putting any oxygen into the water. Due to the low levels of D.O. in the river where water chestnuts grow, the water becomes hypoxic, this occurs when the water’s D.O. level reaches a point when fish start to die. So not only are water chestnuts blocking out other photosynthetic organisms, they are also resulting in the death of fish and macroinvertebrates. As a group, we believe that this trend is interesting and important because the water chestnuts are an invasive species affecting our local communities and more action needs to be taken to stop this species. One member of our group, Michelle, rows on the Hudson, and her oar gets stuck in patches of the water chestnut. There are only a few techniques used to get rid of the chestnut, and they are not very effective. More research and technology needs to be focused on eradicating this invasive species. Michelle spotting a water chestnut patch at the start of her crew race under the Mid­Hudson Bridge. Questions and Hypothesis: The tidal chart reaffirmed our hypothesis that water chestnuts present the biggest challenge for aquatic life during low tide. However, many questions still remain as to why this would occur. We believe that this phenomenon occurs because during low tide, oxygen capacity decreases because the water is spread out over a larger space while the number of water chestnuts remains constant. Another hypothesis is that the water chestnuts may have expanded its range after the mysterious decline of the water celery after Hurricanes Irene and Lee (Hamberg, 2014). We believe that the water chestnut will continue to expand if unchecked in the future, and the D.O. levels in the Hudson will decline. Creative Methods: We have been working together as a science research group for the entire school year. For our other science projects, we created funny, informative videos, so we decided to end our school year by doing another video project for the Data Jam competition. From past experiences, we learned that exciting videos are the best way to grab people’s attention. Our group decided to make a short film that included music video parodies of current hit songs. We felt that this would be the best way to impact and inform people of our generation and so we used Maroon 5’s “Sugar” and Taylor Swift’s “Style” in our video. Reference List: Hamberg, Lars Jonas. "Loss and Restoration of Wild Celery in the Lower Hudson River." ​
Edna Bailey Sussman Foundation Internship Report​
(n.d.): n. pag.​
SUNY College of Environmental Science and Forestry​
. Web. O'Niell, Charles R. "Water Chestnut (Trapa Natans) in the Northeast." ​
NYSG Invasive Species Factsheet Series​
06­1 (2006): n. pag. ​
New York Sea Grant SUNY College at Brockport​
. Web. "Oxygen Levels in Three Aquatic Habitats." ​
Cary Institute of Ecosystem Studies​
. N.p., n.d. Web. 01 June 2015. United States. National Park Service. "Water Chestnut (Trapa Natans)." ​
National Parks Service​
. U.S. Department of the Interior, n.d. Web. 01 June 2015. "Water Chestnut." ​
The New York Invasive Species Clearinghouse​
. Cornell Cooperative Extension, n.d. Web. 01 June 2015.