In 2025, Biosphere Expeditions continued its long-standing citizen-science project in the Maldives, focusing on coral reef health through hands-on volunteer expeditions. Since 2011, these marine surveys have been an important constant of local reef conservation, blending scientific rigour, citizen science and immersive adventure.
The 2025 expedition brought together diverse teams of volunteers and scientists aboard a liveaboard vessel, each group contributing to Reef Check-standard surveys across multiple atolls. These surveys involve underwater assessments of coral cover, fish populations and other ecological indicators to track reef health across time.
Long-term monitoring reveals trends: Outer reefs doing well, inner reefs in slow decline
A special emphasis on revisiting long-term monitoring sites allows Biosphere Expeditions to build multi-year datasets that reveal trends in reef resilience and degradation. The expedition’s work has resulted in annual scientific reports and many publications in the literature.
During the 2025 expedition, citizen scientists surveyed 11 reefs and documented a mixed picture of reef conditions: some sites showed stable or improving coral cover, especially on ocean-fed outer reefs, while inner lagoon sites, more exposed to warming and stress, continued to struggle.
Resilient outer reefs in Ari atoll had maintained levels of coral cover and had reasonably good reef fish populations with 50 – 60% hard coral cover on the deeper surveys (6 – 10 m depth). Some reef sites within atolls showed a further recovery for hard coral cover since the 2016 mass coral bleaching, reaching 40 – 50% cover on more shallow sites (3 – 5 m depth). However, other inner reefs continue to show a ‘phase-shift’ to a non-coral dominated status with opportunistic / fast-growing benthic fauna such as the coralliomorph Discosoma smothering the reef surface at one site (Dega Thila) and currently preventing the re-establishment of corals and other benthic groups.
Study longevity and large datasets thanks to citizen science
A highlight of the Maldives coral reef expedition is its longevity and impact on regional monitoring efforts. Over the past decade, local participants trained in Reef Check methods have gone on to form groups such as Reef Check Maldives, expanding community-based reef monitoring and strengthening links with national marine conservation initiatives.
Data collected by Biosphere Expeditions volunteers feeds into planning for marine protected areas and helps guide management decisions focused on safeguarding reef ecosystems and charismatic species like whale sharks.
Efforts spanning more than a decade yield results in coral reef conservation
With its Maldives coral reef conservation project, Biosphere Expeditions continues to contribute to global reef science by:
Contributing vital data used by NGOs and policy-makers to inform marine protection strategies.
- Maintaining long-term reef monitoring through structured surveys.
- Demonstrating both resilience and vulnerability in coral reef ecosystems.
- Fostering local and volunteer engagement that enhances community-based conservation.
- Contributing vital data used by NGOs and policy-makers to inform marine protection strategies.
Expeditioners speak
Expedition leader and founder of Biosphere Expeditions, Dr. Matthias Hammer, says that “the expedition underscores how citizen science can contribute real, measurable insights into some of the world’s most threatened marine habitats. And at the same time inspire local and international citizen scientists, as well as professional ones, to advocate for ocean conservation well beyond their time underwater”.
Expedition scientist Dr. Simon Harding, a reef ecologist with experience of working on reefs worldwide agrees: “The results highlight the resilience of coral reef ecosystems in that they can recover if there are favourable conditions for coral recruitment and growth through minimising key stressors such as pollution and overfishing. Reducing local stressors also provides the best chance for coral reefs to be more resilient to climate impacts through warming effects such as mass coral bleaching events. Biosphere Expeditions will continue to monitor these coral reefs in the coming years to strengthen further the dataset and provide evidence of both reef recovery and degradation and the linkages to local and global impacts for this critically important ecosystem”.
Maria Ivanenko, one of the coral reef volunteers, adds “What an incredible experience. I learned so much and the reefs were amazing. Wonderful people, great conversations. Glad we can help with conservation efforts to save the reefs here. I love the concept of Biosphere Expeditions and look forward to doing more Reef Checks. Also, huge thanks to the staff, both Biosphere Expeditions and the liveaboard. Keep up the great work.”
Author: Liesl Hammer
Liesl Hammer grew up bilingual in England and Germany with a passion for writing and conservation and holds an English Literature with Creative Writing degree. As the daughter of Biosphere Expeditions’ founder and executive director, she has been on many expeditions, for example to Namibia, South Africa, Oman and Maldives, where she was always captivated by the different cultures, wildlife and wild places she found. Combining all these interests, Liesl now has her own business, helping organisations and businesses improve their social media presence and quality of writing, which is exactly what she does for Biosphere Expeditions – from creating a social media strategy to producing a blog to looking at communication in wildlife conservation.
Video feedback:
(more videos of the expedition across all years are here)
Written feedback:
“What a wonderful way to spend a week. I learned so much about coral and got good at identifying fish. Thank you so much to Matthias, Simon, Jenan and Yaanu for putting so much work into training us and helping us dive safely. And all the crew on the boat – we were so well taken care of! I feel so happy to have been a part of this decades-long mission to understand and protect to the beauty of coral reefs around the world. Thank you Biosphere Expeditions!”
Savannah Schilling, USA
“What an amazing experience. I learned so much and the reefs were amazing. Wonderful people, great conversations. Glad we can help with conservation efforts to save the reefs here. I love the concept of Biosphere Expeditions and look forward to doing more Reef Checks. Also, huge thanks to the staff, both Biosphere Expeditions and Dune. Keep up the great work.”
Maria Ivanenko, USA
“Wow, what an amazing expedition. I cannot believe this is real life and I got to do this! The ocean is the most amazing, giving place in the world and I’m forever grateful I now have the opportunity to give back to in. Once in a lifetime week.”
Tess Kneebone, USA
Thanks for this amazing experience.
Vanessa Mann, Germany
The training is very good. I felt confident about what to do and identify despite having no previous knowledge. The boat staff were very warm, helful and friendly, and made me feel welcome and comfortable.
Zach Churchill, Canada
I would really like to thank Biosphere Expeditions for giving me a placement on this incredible expedition. The Reef Check protocol and all other contents of this project were very useful to better my career in ocean conservation. I would highly recommend more locals to take up this opportunity.
Muf Ziyadh, Maldives
I am so grateful that I got to join this expedition as a placement. This has helped me get valuable underwater survey skills that I haven’t had the opportunity to develop before and will greatly enhance my CV as a marine biologist. It has been so much fun doing the Reef Check surveys and I am feeling inspired to become a Reef Check Trainer in the future. Thank you so much for allowing me to take part. I am delighted to walk away with a Reef Check EcoDiver certification and amazing dives and memories, and new knowledge.
Bennath Chillingworth, UK
Photo archive
(more photos of the expedition across all years are here):
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