Innovative Diver-Operated Microscope Reveals Coral Biology at Microscale

A groundbreaking advancement in coral research is underway with the introduction of the Benthic Underwater Microscope Imaging PAM (BUMP), a diver-operated microscope developed by scientists at the University of California, San Diego's Scripps Institution of Oceanography. This innovative tool, detailed in a study published on July 3, 2025, in the journal *Methods in Ecology and Evolution*, employs pulse amplitude modulated (PAM) light techniques to examine coral photosynthesis at an unprecedented microscale.

The BUMP microscope allows researchers to assess coral health and physiology in situ, significantly enhancing efforts to understand the phenomenon of coral bleaching—a process wherein corals expel the symbiotic microalgae crucial for their survival due to environmental stressors like rising sea temperatures. According to Dr. Or Ben-Zvi, a postdoctoral researcher at Scripps and lead author of the study, "This microscope is a huge technological leap in the field of coral health assessment." The instrument enables scientists to visualize the interactions between corals and their microalgae, revealing insights into the microalgae's photosynthetic efficiency within coral tissue.

Historically, coral reefs have faced significant threats from climate change, pollution, and overfishing. The phenomenon of coral bleaching has led to the degradation of these vital ecosystems, which are essential for marine biodiversity and coastal protection. A report by the United Nations Environment Programme (UNEP) in 2023 stated that approximately 50% of the world’s coral reefs are at risk of collapse if current trends continue.

The BUMP microscope, designed by engineers and marine researchers in the Jaffe Lab, is lightweight and portable, allowing divers to transport it without extensive equipment support. The device is capable of capturing high-resolution images and videos of corals, utilizing focused LED lights and high-magnification lenses. Initial field tests conducted in diverse marine environments, including the Red Sea and Hawaiian reefs, have provided researchers with novel observations of coral behavior and physiology.

Dr. Jennifer Smith, a marine biologist at Scripps Oceanography, noted, "We are visualizing photosynthesis, something that was previously unseen at the scales we are examining, and that feels like magic." The implications of this technology extend beyond corals, with potential applications for studying other small-scale marine organisms that also rely on photosynthesis, such as kelp.

The insights gained from the BUMP microscope can be invaluable for developing strategies to mitigate the impacts of climate change on coral reefs. By allowing for the non-invasive assessment of corals, researchers can gather crucial data that may provide early warnings of environmental stressors before irreversible damage occurs, as emphasized by Dr. Paul Roberts, a co-author of the study now with the Monterey Bay Aquarium Research Institute.

While the BUMP microscope represents a significant advancement in marine research technology, the need for ongoing conservation efforts remains critical. As Dr. Dimitri Deheyn, another co-author, remarked, "Since photosynthesis in the ocean is important for life on Earth, a host of other applications are imaginable with this tool." The collaborative efforts of scientists at Scripps Oceanography highlight the importance of interdisciplinary approaches to tackle the challenges facing coral reefs and marine ecosystems globally.

In conclusion, the development of the BUMP microscope not only enhances our understanding of coral biology but also serves as a crucial tool in the fight for coral conservation. As climate change continues to pose threats to marine life, innovations such as this microscope offer hope for preserving the delicate balance of underwater ecosystems.