Team members: Mayukh Dey, Rohan Arthur, Chris Perry and Jagdish Krishnaswamy

Whether or not reef growth rates are able to keep up with background sea-level rise has important consequences for the integrity of atolls. Reefs that lag behind sea-level rise have greater depth of water and therefore provide little friction to incoming waves. As a result, swell waves generated at sea are able to pass over deeper waters without any loss in energy and have the potential to inundate islands and erode coastlines. Another important function of reefs are its sediment generation potential that ensures islands are able to adjust to rising sea-levels.

Sediments generated by the erosion processes in coral reefs are the only source of sediments in atolls. This is in sharp contrast to the generation of sediments along the coastlines of Andamans and Nicobar or mainland India, where both reef derived sediments and those carried by rivers contribute to beach sand. 

Project objective:

• Determine critical wave buffering and sediment generation functions of coral reefs

• Identify weather events that pose a threat to residents

In this project, we aim to first quantify the physical hazards that impact the islands of Lakshadweep. Tying together information from the reef accretion project, we aim to determine critical wave buffering and sediment generation functions of coral reefs. We also describe the hazards that pose a threat to the residents in Lakshadweep by analysing extreme weather events and identify areas that are at risk of flooding, based on fine-scale island elevation measurements. We aim to measure the ability of coral reefs in the Lakshadweep to generate sediments and measure how current rates of reef accretion can attenuate waves and protect the islands from extreme wave events.

We use in-water surveys to measure rates of reef growth, along with estimating the abundance of eroders in the reef. Based on existing literature, we measure the sizes of sediments that are generated and attribute them to different organisms in the reef. We collect sediment samples to further examine the role of foraminiferans in influencing sediment generation rates in coral reefs in the Lakshadweep.