COS 12-5 - Mimicking the architecture of natural ecosystems to create a harvestable and self-regulating indoor ecosystem – A test of the concept

Monday, August 8, 2016: 2:30 PM
222/223, Ft Lauderdale Convention Center
Matthew P. Hammond1, Jurek Kolasa1, Phil Fung2, Golara Farhoomand1 and Mike Takahashi1, (1)Biology, McMaster University, Hamilton, ON, Canada, (2)Indoor Nature Design Inc., Markham, ON, Canada

An emerging trend in designer ecosystems is to integrate species assemblages into buildings for food, aesthetics and other useful functions. But what features of natural systems should be mimicked and incorporated into novel, human-made ecosystems? We identified eight features of biodiversity and ecosystem organization that underpin the stability and productivity of natural systems (portfolio and insurance effects, complementarity, habitat heterogeneity, food web topology, constraint, metapopulation dynamics and biological control) and incorporated these into an aquaponics-like system. Our goal was to create an attractive fish and plant growing system that runs on kitchen waste. The 1.75m3 indoor ecosystem consists of >20 species housed in four tiers of aquaria that are connected by recirculating water flow. Tiers have complementary functions and include: (1) A terrestrial module of compost, decomposers, plants and biological sand filters, (2) a primary producer module of phytoplankton, (3) a secondary producer module of water flea (D. magna) and oligochaete worm (Tubifex sp.) subpopulations, and (4) a secondary consumer module of tilapia (O. niloticus). We hypothesized that meaningful biodiversity and organizational features like physical separation of trophic levels and metapopulation structure would lend the system productivity and long-term stability for supporting biota. 


Preliminary results show high stability of populations and water chemistry and moderate productivity. After a period of nutrient aggradation, aquaria established distinct habitats with stable water chemistry (e.g., Coefficient of Variation = 0.01-0.19 for pH and dissolved oxygen). Physical separation of trophic levels led to stable source-sink dynamics as intended; compost leachate spurred growth of phytoplankton (up to 84 ug/L chlorophyll a) and hydroponic plant growth; phytoplankton subsidies supported moderate water flea productivity (up to 27 ind. L-1 d-1); and water flea and duckweed (Lemna minor) subsidies supported growth of several small tilapia. Findings demonstrate that the performance of small-scale, designer ecosystems may be enhanced by mimicking biodiversity and organizational patterns of thriving natural ecosystems. Of particular interest is the potential for these design elements to improve the sustainability and self-regulating capability of engineered ecosystems. We note, however, that further innovations and efficiencies may be needed to support intensive fish and crop growth.