<P> They consumed the same low - calorie, nutrient - dense diet which Roy Walford had studied in his research on extending lifespan through diet . Medical markers indicated the health of the crew during the two years was excellent . They showed the same improvement in health indices such as lowering of blood cholesterol, blood pressure, enhancement of immune system . They lost an average of 16% of their pre-entry body weight before stabilizing and regaining some weight during their second year . Subsequent studies showed that the biospherians' metabolism became more efficient at extracting nutrients from their food as an adaptation to the low - calorie, high nutrient diet . </P> <P> Some of the domestic animals that were planned for the agricultural area during the first mission included four pygmy goats and one billy goat from the plateau region of Nigeria, 35 hens and three roosters (a mix of Indian jungle fowl (Gallus gallus), Japanese silky bantam, and a hybrid of these), two sows and one boar pig (feral), as well as tilapia fish grown in a rice and azolla pond system originating millennia ago in China . </P> <P> A strategy of "species - packing" was practiced to ensure that food webs and ecological function could be maintained if some species did not survive . The fog desert area became more chaparral due to condensation from the space frame . The savannah was seasonally active; its biomass was cut and stored by the crew as part of their management of carbon dioxide . Rainforest pioneer species grew rapidly, but trees there and in the savannah suffered from etiolation and weakness caused by lack of stress wood, normally created in response to winds in natural conditions . Corals reproduced in the ocean area, and crew helped maintain ocean system health by hand - harvesting algae from the corals, manipulating calcium carbonate and pH levels to prevent the ocean becoming too acidic, and by installing an improved protein skimmer to supplement the algae turf scrubber system originally installed to remove excess nutrients . The mangrove area developed rapidly but with less understory than a typical wetland possibly because of reduced light levels . </P> <P> Biosphere 2 suffered from CO levels that "fluctuated wildly," and most of the vertebrate species and all of the pollinating insects died . Insect pests, like cockroaches, boomed . In practice, ants, a companion to one of the tree species (Cecropia) in the rainforest, had been introduced . By 1993 the tramp ant species Paratrechina longicornis, local to the area had been unintentionally sealed in and had come to dominate . </P>

An important conclusion drawn from the initial biosphere 2 project was that