Discovering and describing Aquatic Fungi

I study aquatic fungi associated with wood decaying substrates. I have collected in Central and South America, where we describe new species and genera.

My previous work has described how aquatic fungal communities assemble on wood substrate in freshwater, brackish and marine habitats and has quantified their effect on wood chemistry and mass loss. I hope to continue to collect tropical aquatic fungi, not only to describe novel species and their habitat preferences, but also to better understand their ecological role in aquatic ecosystems.

Root nodule associated microbiota of the tropical conifer Podocarpus in Panama ​

The temperate and tropical tree genus Podocarpus has unusual nodulated roots that do not host N-fixing bacteria. We are examining the factors that structure communities of fungi and bacteria in Podocarpus roots and these fungi may impact nutrient acquisition in low fertility lowland and montane tropical forests.

The association of the tropical legume tree Tachigali versicolor  with the basidiomycete fungal genus Amauroderma

Amauroderma is a genus of stipitate polypore fungi that we have observed to be associated with standing-dead individuals of the legume canopy tree Tachigali versicolor.

This fungal association is intriguing because of the unusual monocarpic life history of Tachigali, where trees only reproduce once in their lives and then die. I have found that Amauroderma uniquely specializes on Tachigali, and furthermore is restricted to the roots of Tachigali trees that are either currently reproducing, or that recently reproduced and died. Such strong host-specialization appears to be rare among polypore fungi.

The association with reproductive Tachigali trees raises questions as to whether Amauroderma is parasitic, and whether its presence is related to the tree’s reproductive events.

Microbial community assembly of aquatic fungi (also, bacteria and archaea) and wood decay processes

Historically, aquatic fungi have been studied as two distinct ecological groups: freshwater and marine fungi, limiting our understanding of their habitat preferences.  

This led to a project on fungal community assembly on wood along a salinity gradient.

Our results showed that wood is decayed by distinct microbial and invertebrate communities as it travels from rivers to the ocean. Contrary to expectations that wood decays slowly in water, we found decay rates in estuarine and marine ecosystems comparable to that on land, with loss of lignin, the most recalcitrant polymer in plant tissue, proceeding fastest in the ocean. Estuaries and coastal oceans are therefore hotspots not just for the processing of particulate and dissolved organic carbon, but also for inputs of woody debris, reducing inputs of terrestrial carbon to marine sediments.