Desert Sea

 A Degraded Reef, a Chance for Renewal

What do you see when you look at the Biosphere 2 ocean?

Biosphere 2’s ocean began as a thriving coral reef, with hundreds of species of marine organisms that originated from tropical oceans worldwide. Maintained as a reef during the Biosphere missions and later by Columbia, the reef fell into neglect while the facility was in transition. Algae overtook the corals, and the biodiversity plummeted. Although the community has been stable for many years now, it is essentially a degraded reef, overgrown by algae and low in biodiversity.

Sadly, this decline mirrors the fate of many reefs worldwide, which are suffering from degradation that has led them along a similar path. Without active removal of algae (by fish and grazing invertebrates in the real ocean, by humans in B2), corals cannot sustain themselves against overgrowth. Without effective recycling of nutrients, algae flourish and the water quality degrades. Can this degradation be reversed? At Biosphere 2, we have the opportunity to do this. We hope to learn lessons along the way that will help reefs everywhere.

A Desert Sea

Our nearby ocean, the Desert Sea or Gulf of California, provides a compelling model to guide the recovery of Biosphere 2’s ocean. The Sonoran Desert owes its biological and cultural diversity in no small part to its proximity to the rich waters of the Gulf of California, yet many who visit B2 have little notion of the tight connection between desert and sea. In the southern Gulf lies a subtropical coral reef, Cabo Pulmo, rich in fish and invertebrates, protected as a marine park by Mexico.  This habitat will provide a model for rejuvenating the Biosphere 2 ocean. In addition to hard and soft coral and other reef denizens, we will incorporate intertidal and shallow subtidal communities characteristic of the Gulf’s rocky reefs and sargassum beds.

The Gulf of California is among the most diverse seas on the planet and stretches over 1000 km. This incredible place provides us with a rich array of opportunities for education, research, and outreach. But the Biosphere 2 ocean can accommodate just a fraction of the real Gulf’s incredible diversity of species and environments. We will supplement the rejuvenated ocean ecosystem with tanks and exhibits in the Ocean Gallery to showcase ecological communities from other parts of the Gulf, and to highlight cultural and environmental connections with the southwestern US.

A Unique Research and Education Facility

We expect the revitalized ocean to provide a rich platform for research opportunities, including marine ecology, biogeochemistry, ocean acidification, genomics, conservation biology, and instrumentation development. The B2 ocean has a robust research history, notably in pioneering ecosystem-scale studies of ocean acidification and in the testing and development of now widely used microbial assessment methods.

As we transition from a ”crashed” coral reef to a rejuvenated, diverse subtropical reef, we envision that researchers can utilize the ocean as a unique, controlled environment for marine biological studies at all scales. We can explore how diversity is expressed from the genomic through the community scale, how organisms respond to changes in water quality and chemistry, and develop strategies for ecosystem recovery that may apply to natural marine systems globally. We expect the focus on the Gulf of California to foster strong bi-national collaborations with Mexican researchers with expertise and interest in the Gulf of California.

Together with the Ocean Gallery, we envision the B2 ocean as a living model of the Gulf of California that will highlight the rich ecology, diverse human cultures, and conservation challenges that are concentrated in this unique sea. Opportunities for education and outreach will multiply through enhanced visitor interpretation, new K-12 curriculum development, and special programs built around Gulf themes. And, as for research, we anticipate expanding opportunities for bi-national collaboration with Mexican students, educators, and conservationists.

What’s going on now?

Our first steps are to understand how the current B2 ocean differs from the Gulf, and alleviate those differences. We are actively working to bring the water chemistry into closer agreement with the natural ocean, and to remove the overgrowing algae. Once the water conditions are appropriate, we’ll bring in organisms that eat seaweed and filter the water naturally. As the water clears up, and we achieve sustainable reductions in bottom-growing algae, we can begin to introduce species more characteristic of the Gulf, including corals that flourish in subtropical conditions.  We’re engaging scientists from many different fields to participate in this process.

Meanwhile, other scientific projects proceed unabated, including the development of autonomous sensors, algal surveys, plastics degradation exploration, and assessment of our mangrove system.

Our Ocean Gallery is transitioning too! The “Return to the Sea of Cortez” exhibit chronicles the storied journey of author John Steinbeck and marine biologist Ed Ricketts to the Gulf in 1940. This remarkable journey, which brought together ecology, philosophy and the fellowship of two active minds, is one of the finest examples of collaboration between science and the arts. The exhibit reveals what was discovered when scientists and writers retraced the original journey 60 years later. The late Dr. Rafe Sagarin, Biosphere 2 marine ecologist, was a key part of this expedition.

Ocean Viewing Gallery                              OVG Tanks





While touring the Ocean Gallery, visitors will find large viewing windows to see under the surface of the existing Biosphere 2 ocean, while smaller aquaria populated with colorful Gulf of California species give a preview of the kinds of life forms we’ll bring to the Desert Sea transformation.

Get involved!

We are fortunate to have a great group of volunteers who have been maintaining the ocean tank and are excited to build for its future. We will be working with scientists, aquarists, museum designers, and artists from the U.S. and Mexico, to ensure that the changes we make help achieve Biosphere 2’s research, outreach and education goals. We would love for YOU to be a part of this transformation. If you would like to volunteer, plan your research project around the ocean, or know of a student or scientist who should be part of this project, let us know!  Contact Katie Morgan at

Model Systems


2016 (Published)

Between control and complexity: opportunities and challenges for marine mesocosms . Sagarin, R.D., Adams, J., Blanchette, C.A., Brusca, R.C., Chorover, J., Cole, J.E., Micheli, F., Munguia-Vega, A., Rochman, C.M., Bonine, K., van Haren, J. and Troch, P.A. (2016): Frontiers in Ecology and the Environment 14(7): 389–396.