麻豆淫院

Coral reefs form a vital part of the marine ecosystem, playing host to diverse species and supporting multiple industries, including fisheries, tourism, and recreation. However, these fragile ecosystems are under increasing threat from climate change, with warming oceans increasing stress on the coral animals and their symbiotic algal partners.

A new remote sensing tool developed by KAUST researchers has created an effective and efficient method of monitoring and predicting both the scope and severity of coral bleaching in the Red Sea. The study is in the journal Remote Sensing in Ecology and Conservation.

The tool鈥攄eveloped by KAUST in partnership with SHAMS, General Organization for the Conservation of Coral Reefs and Turtles in the Red Sea鈥攃ould aid conservation management and policymaking by enabling targeted, integrated management strategies to prioritize specific areas for intervention. It is applicable in the Red Sea as well as across the world.

The algae living within corals share nutrients and resources, giving corals their distinctive color. When corals are under stress and competing for limited resources, they "kick out" their algal partners that help with nutrition. This results in bleaching, where corals lose their pigmentation and gradually turn white. This process weakens the coral animal and leaves it more vulnerable: Prolonged bleaching events can kill corals and decimate reefs.

"Monitoring the health of coral reefs amid climate change is crucial, and satellite remote sensing provides a cost-effective strategy that is more efficient than traditional field sampling, which can be time-consuming and resource-intensive," says Elamurugu Rajadurai Pandian at KAUST, who worked on the project during his Ph.D., under the supervision of KAUST's Ibrahim Hoteit.

The new tool utilizes the extensive datasets collected by satellite imaging every five days. While previous studies have used satellite imaging to monitor coral bleaching events, the team took this technique a step further by including an analysis of the severity of bleaching. This means that areas can be rapidly graded according to how intense the bleaching is likely to become.

"Healthy and bleached corals reflect light differently, and satellites can detect these variations," says Rajadurai Pandian. The researchers took advantage of these differences in color and brightness in thousands of satellite images to accurately identify bleached corals.

First, they analyzed how much light was reflected from the ocean floor by both healthy and bleached corals. Then, they used a mathematical technique called the least-squares approach. This helped identify patterns in the data and accurately segregated bleached corals from healthy ones, making the overall detection rate more precise and reliable.

"The detection accuracy depends on the atmospheric correction of satellite imagery, which is complicated by the Red Sea's proximity to deserts and frequent dust storms," says Rajadurai Pandian. "We used an advanced algorithm that removed erroneous reflectance values caused by aerosols and particulates. This significantly improved the accuracy of satellite ocean color data retrievals in our model, particularly over the complex, reef-filled shallow waters of the Red Sea."

Their model also has improved spatial resolution compared to previous models, providing detailed analyses of coral health every 10 meters. By monitoring bleaching severity, ranging from low to high, scientists can gain deeper insights into coral resilience and recovery potential.

"By serving as an early warning system for coral bleaching, our method will enable faster responses and better conservation strategies," concludes Hoteit. "Such high-resolution monitoring will support sustainable fisheries and tourism management while also contributing to climate change research by tracking environmental changes in marine ecosystems."