As a former graduate of MEL, my journey of microbial ecology started in physiology and ecology of aerobic anoxygenic phototrophic bacteria (AAPB). We found bacterio-chlorophyll a (BChla)/Chlorophyll a ratio is higher in open-ocean areas than it is in coastal environments, indicate that BChla-based phototrophy plays an important role in the carbon cycle for the ocean. Subsequently, as the only Chinese recipient of Fulbright S&T Fellowship in 2009, I began my Ph.D. in environmental microbiology in the University of Maryland College Park. My graduate work on sponge microbiome suggests that microbial symbionts can help their hosts gain a competitive edge in resource-constrained habitat through efficient nitrogen and phosphorus cycling. To crack detail mechanisms in the intricate symbiosis, my postdoc work in Baylor College of Medicine utilize powerful genetic and cell biology toolbox from nematode C. elegans to explore regulatory networks in microbially mediated nutrient cycling that might be universal among animal kingdom.
Regarded as the “rainforest of the sea”, coral reefs cover just under 0.1% of the world ocean surface with extremely low nutrient. But they are home to about 25% of marine living organisms and rank among the most productive ecosystems on Earth. For a long time, researchers have been puzzled by this ecological conundrum, commonly referred to as “Darwin’s Paradox”: how can such low nutrient support one of the most productive and bio-diverse ecosystems?
My study on sponge microbiology provided evidence that close association of microbe and animal in could be the answer. Marine sponges are major habitat-forming organisms in benthic communities and have an ancient origin in evolution history. Compare with recent advance in carbon and nitrogen cycle, phosphorus cycle in this symbiont system remain understudied. Here we report significant accumulation of polyphosphate granules in three common Caribbean sponges. The identity of the polyphosphate granules was confirmed by physical, chemical and molecular methods. Based on these observations, we propose here a phosphorus removal pathway through symbiotic microorganisms of marine sponges. This process may have a significant impact on the phosphorus cycle in coral reef ecosystems and likely contributed to oxygenation of the ocean in Early Neoproterozoic era.