University of Central Florida Undergraduate Research Journal - Preventing Introductions to Sustain Healthy Ecosystems: Establish Eradication Protocols for a Popular Aquarium Seaweed
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After the global invasion of Caulerpa taxifolia, public knowledge has increased about the dangers of aquarium dumping. However, there is a void in scientifically–based knowledge on proper disposal techniques; many researchers focus on chemical, biological, and mechanical eradication of already invasive species (Odom et al. 2014). In response, we proactively focused on preventing initial introductions by providing hobbyists with a safe, simple, and affordable disposal technique for C. linum to preserve the integrity of the ecosystem.

The minimum dosage of acetic acid needed to cause 100% mortality of a 10 cm fragment of C. linum within 24 hours was 4% for 10 minutes. In Trials 1 and 2, 2% acetic acid at 60 minutes was also found to eradicate 1 cm and 10 cm fragments within 24 hours. However, we focused on finding a lower exposure time for the convenience of hobbyists. Treating algae at double the concentration for 10 minutes cuts out 50 minutes of exposure, which we believe will encourage more hobbyists to utilize this quick and simple method. We suggest aquarium hobbyist treat their water and any macroalgae fragments with 4% acetic acid which they can easily access through the use of commercial vinegars. Commercial vinegars range from 4–6% acetic acid and are safe for any household, which places the task of responsible tank disposal on everyone. In order to cause 100% mortality, C. linum should be exposed to commercial vinegar for 10 minutes before disposal. For stores and growers, experimental-grade acetic acid can be diluted to 4% solution and may be more cost effective on a larger scale.

Previous studies by Odom and Walters (2014) documented full mortality of Chaetomorpha at 2% acetic acid for 4 minutes and 4% for 1 minute. These results were for the eradication of 1 cm fragments with blotted dry, wet weights of 4.1 to 5.7 mg (Odom and Walters 2014). In contrast, our experiment focused on 10 cm fragments once they were determined to have higher survivorship than 1 cm fragments in Trials 1 and 2 (Figure 1). Comparison of our results with Odom et al.'s study (2014) portrays that larger fragments of C. linum may have higher survival rates and require larger concentrations or exposure times to promote complete eradication. When treating larger fragments or clumps of C. linum, more research is suggested to measure 100% mortality. Large clumps of C. linum can additionally be disposed of in a landfill (Odom and Walters 2014).

The monitoring time period is also an important factor that accounts for the differences between our experiment and previous studies. While Odom and Walters' results were documented for survival across a 4–week period, our experiment monitored survival after 24 hours. This factor is important because in the wild, a fragment could quickly be presented to different conditions in each waterway that cannot be accounted for in the laboratory setting. Nutrients in the natural water may reverse degradation and promote survival. Future studies could test the immediate and long–term responses of C. linum fragments in the wild after treatment with acetic acid.

Utilization of these results is highly recommended due to Chaetomorpha's great invasive potential. In addition to having broad environmental tolerances, high nutrient uptake rates, and the ability to reproduce from very small fragments, Chaetomorpha also has the tendency to clump together in dense mats (Littler and Littler 2000). When these mats get trapped in benthic communities, they negatively affect the ecosystem by dissolving oxygen and extracting nutrients. Chaetomorpha has been documented to have bloom–forming growth in response to eutrophication in nutrient rich water (Lapointe 1997). Dense filamentous clumps and blooms can block sunlight, which will negatively affect the photosynthesis of coastal species. More research is required to discover the full effects of Chaetomorpha in a variety of ecosystems.

These results could be a tool for government and park officials in the case of future invasion. If the results are used for a potential invasive clean up, the experimenters recommend further research on the effects of acetic acid on the ecosystem. A concentration of acetic acid equal to or greater than 5% has been documented to have negative consequences on estuary species (Locke et. al 2009). Since this experiment recommends 4% at 10 minutes for full mortality, additional research should be done on lower concentrations and more extended exposure times to apply to affected waterways.

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