New Species of Chalk Forming Organisms and Further Accumulations Found within the Faafu Atoll, Maldives
Summarized by Nathan Baker, who is a senior and future geologist at the University of South Florida. His interest in the geosciences lie within geophysics and tectonics. He hopes to attend graduate school in structure and plate tectonic studies. Outside the classroom, Nathan enjoys going to the gym, hanging out with friends, and being active outdoors.
Hypothesis: This research aims to pinpoint the distribution of coccolithophores, a type of algae and microorganism too small to be seen by the naked human eye (and the organism that chalk is composed of), in the Faafu Atoll of the Indian Ocean’s Maldives while introducing a new species, Alisphaera bidentata. The study delves into the variety of coccolithophore species in the ocean, examining the correlation between the number of species and water temperature through measuring a number of different variables, explained below. Moreover, this paper provides insight into the ecological and environmental impacts that these microorganisms have on the climate.
Data Used: The study analyzes the area surrounding the island using various data points, such as location, depth, time, weather, temperature, conductivity, pH, O2 levels, O2 saturation percentage, and the amount of chlorophyll in the water. Scientists also collected and identified samples of coccolithophores to determine species diversity.
Methods: As part of this study, three water samples were collected from Faafu between November 2nd and November 6th, 2018. The samples were taken from both deep reefs (between 45 m and 3050 m deep) and flat reefs (which separate lagoons and the deep ocean). Each sample was recorded with a GPS device. Water temperature and oxygen concentrations were measured at each location. Surface samples of water containing coccolithophores were collected from a boat using a bucket off the coast of the islands. Along with this, vertical water samples at 0 m, 10 m, 25 m, and 40 m deep were collected using devices that can withstand high-pressure environments in the deeper ocean. Once the samples were collected, water analysis began. The first step in analyzing the samples was filtration. Samples containing two liters of water were sent through filters that separated the organisms from the saltwater. These organisms were then dried and viewed under a microscope to record the number, concentration, and types of coccolithophores.
Results: Scientists found that the density of coccoliths in surface waters was lower than that in waters with depths of 1-2 m, and the density continued to increase towards the bottom depths in both the lagoon and deep ocean environments. When investigating the vertical samples, scientists noted that there was a 1℃ decrease in temperature, observed from the surface to depths of 40m, along with a decrease in oxygen concentration within the lagoon environment. Within the open ocean environment, there was a 0.5℃ decrease in temperature, along with a decrease in oxygen concentration. Chlorophyll readings demonstrated overall low concentrations at all stations but showed a slight increase at larger depths.
Out of the multiple coccoliths species identified (16), only two were abundantly common within both open water and lagoon areas. The most abundant species were Gephyrocapsa oceanica and Oolithotus antillarum (as shown in figure 1). The concentrations of G. oceanica and O. antillarum increased with depths in both the lagoon and deeper ocean. Within these increasing depths, minor species also became more prevalent. An interesting find was that all 16 species of coccoliths existed in all of the sampled environments. Researchers also discovered a new species of coccolith (Alisphaera bidentata), which among the lesser commonly occurring species in these samples; further testing will be needed to understand the organism’s lifestyle.
Study Importance: This study mapped the overall abundance of coccolithophores of the island of Faafu Atoll in the Maldives. The data showed that, of the 16 species found, the most abundant were Gephyrocapsa oceanica and Oolithotus antillarum. Along with these major species, numerous minor species were also detected within the waters around Faafu. Scientists, through this study, were better able to quantify how coccolith diversity is related to water conditions.
Broader Implications. This study is important due to the effects coccoliths can have on the environment. Coccolithophores can affect the environment through the use of photosynthesis. By removing CO2 within the oceans and atmosphere, coccolithophores play a role in stabilizing ocean acidity and atmospheric conditions, and broadly play a role in stabilizing climate and ocean health. Additionally, the pH in the ocean can be influenced by the amount of CO2 removed from the water, which, in turn, can prevent marine disasters such as coral bleaching and red tides. Furthermore, comparing the data of these coccoliths to other regions of the world can help identify the rate of CO2 absorption and possibly identify reasons why certain regions are affected by global warming more than others.
Full citation: Malinverno, E., Leoni, B., & Galli, P. (2022). Coccolithophore assemblages and a new species of Alisphaera from the Faafu Atoll, Maldives, Indian Ocean. Marine Micropaleontology, 172, 102110. https://doi.org/10.1016/j.marmicro.2022.102110