Life Support For the Super Reefs Of The Future
Re-engineering plans for the Biosphere 2 ocean reef are well underway and on track to be finalized in November 2018. The planned renovations will allow us to build and improve upon the infrastructure of the original B2O reef experiment in a number of key ways. For example, the quantity and wavelength of light reaching the B2O reef, lower and more selective than typically found in nature, provided a continuous source of stress to the original B2O coral reef. When the ocean was initially populated, coral depths were tediously manipulated to reduce stress (Abigail Alling, pers. communication). The re-engineered B2O will have a series of trusses supporting up to 288 halogen and LED lights to supplement lighting over the reef. We are optimizing the location of the lighting grid relative to the underlying bathymetry to ensure proper lighting over all planned experimental regions (from the shallow water lagoon to the reef crest to the deep fore-reef environment, Figure 1).
In addition to new lighting structures, we are also upgrading the life support systems to improve heating/cooling, filtration, circulation, and water quality of the B2O. By early 2019, we will upgrade the old heat exchanger to facilitate realistic stress-hardening and thermal-stress experiments. These new systems will permit the background temperature of the B2O to be manipulated across a broad range of temperatures (from 25 to 35 degrees Celsius) and at a rate of up to 2 degrees Celsius per day – rates that are commonly observed in nature during extreme bleaching events and across many reefs on a diurnal or even tidal cycle. The ability to simulate high background temperature variability will be essential for stress-hardening and future-resilience experiments in phases 2 & 3, as a number of studies have demonstrated that reefs are less likely to severely bleach if they are frequently exposed to temperature extremes.