Discipline: Ecology Environmental and Earth Sciences
Latia Jackson - Virginia State University
Co-Author(s): Mayah Dunham, Shobha Sriharan, and Jason Adolf
From generating half of Earth’s oxygen, to causing ecologically hazardous algal blooms and potentially permanently harmful toxins, phytoplankton induce a great deal of curiosity and interest within the scientific community. In addition to their potentially harmful effects, phytoplankton are also great indicators and measures of aquatic health. The hypothesis of this study is that phytoplankton in Hilo Bay increase the turbidity of water and decrease the circulation of water. As an Intern in the NSF HBCU UP Supplemental Grant, I collected water samples on weekly basis in a 250 ml bottles from Hilo Bay buoy and immediately taken to the lab. Before any collected phytoplankton could be observed and identified, each sample had to be properly preserved and prepared for the Hitachi S3400NII Scanning Electron Microscope (SEM). The initial step in preparing the sample was to preserve the phytoplankton in a Lugol’s solution. 12.5 ml of already prepared Lugol’s solution was added to the 250 ml sample. 50 ml of the preserved sample was then added to a settling tower (or is it chamber?) and covered in order to ensure that the phytoplankton would not receive any light damage. The sample would remain in the settling tower overnight to allow for a thorough concentration of 2 ml of collected phytoplankton. Once the sample remained in the settling tower overnight the 2 milliliters of phytoplankton concentration was pipetted into a valve and 10 ml of Glutaraldehyde and chilled in the laboratory refrigerator. Afterwards the sample underwent ethanol dehydration. The dehydrated sample was then mounted on a 15 millimeter aluminum stub with double sided carbon sticky tape. In order for the sample to be observed with the SEM it was necessary that the sample be gold coated to reduce charging of the specimen. The sample was then mounted into the SEM chamber. After carefully adjusting various parameters on the SEM, such as the probe current, accelerating voltage, and objective aperture, images were generated of the phytoplankton from the water sample from Hilo Bay. After generating at least one image for each apparently different phytoplankton, they were then identified by genus using a dichotomous key. This was repeated weekly for all the samples. The species of the common diatoms or dinoflagellates found in Hilo Bay were imaged under the University of Hawaii at Hilo’s Hatachi S-3400 II scanning electron microscope.
Funder Acknowledgement(s): NSF HBCU-UP
Faculty Advisor: Shobha Sriharan,