Adaptation Biogeography Taxonomy Conservation
I am broadly interested in many aspects of biological sciences in the marine realm, particularly with regards to evolution, adaptation, biodiversity, biogeography, ecology, conservation, and taxonomy. My research aims to discover and document the biodiversity in our oceans, and to understand evolutionary mechanisms and trajectories generating phenotypic diversity leading to adaptive novelty.
A part of my research involves finding out what organisms inhabit ‘extreme’ environments, particularly deep-sea hydrothermal vents and other chemosynthesis-based ecosystems, and what factors determine their distribution and connectivity among different sites. Often these species are undescribed and without a name, which requires researchers like myself to give them names and make them visible. In the dawn of deep-sea mining industry and an era of rapidly changing environment, such data are crucial to the conservation of animals inhabiting these unique ecosystems.
Molluscs (phylum Mollusca) is the second largest phylum of living animals containing over 100,000 living species, including animals such as snails, clams, octopuses, nautiluses, chitons, and many more. They are not only megadiverse in terms of species richness, but also in morphology and adaptations, having conquered many ‘extreme’ environments. This makes molluscs an excellent study group.
I combine morphological (e.g., histology, dissection, microscopy) and molecular (e.g., phylogeny, population genetics, genomics) methodologies in my work, and constantly seeks for new methods to answer the scientific question at hand.
Some specific aspects of my research are as follows.
Adaptations to Extreme Environments
Anatomical Adaptations
One of my key interests is in exploring how molluscs (and other organisms) evolved to adapt to ‘extreme’ environments, particularly deep-sea hydrothermal vents. A key aspect of adaptation is the evolution of anatomy. I currently undertake research to elucidate ways animals have modified their body to be able to succeed in hydrothermal vents and other ‘extreme’ environments using 3D anatomy reconstructed by serial sectioning or synchrotron CT scans via the specialist software AMIRA.
Example 3D anatomical reconstructions. Above: Chrysomallon, Below: Gigantopelta
Molecular Adaptations
Any adaptation at the phenotypical level must, of course, have a genetic basis. The advancement of next-generation sequencing and ‘omics’ provide unprecedented opportunities for studying the molecular basis of evolutionary adaptation. I am part of several ongoing research projects combining genomics and transcriptomics to understand gene expression patterns and selection pressures faced by deep-sea animals.
Using genomics to solve the origin of scales in the Scaly-foot Snail
Biogeography
Understanding the distribution of evolutionary lineages in geographic space and through geological time is key to elucidating factors behind species composition, distribution ranges, biological interactions, and basic biological processes such as speciation. Most of the available living space on Earth is in the oceans and most of that is, in turn, in the deep-sea. Researches into the biogeography of the marine environment is therefore essential to perceiving how life have flourished the way it is on planet Earth. The tool of choice I have used to address biogeographic questions is population genetics, often in combination with ocean current modelling.
An example haplotype network showing genetic connectivity among three populations (from Chen et al., 2015: Org. Div. Evol.)
Taxonomy and Systematics
Relationships among living organisms is a fundamental question in biology, but even with modern phylogenetic / phylogenomic methods many questions remain to be answered. For example, the deep relationships among the eight living classes of Mollusca is still a subject of much debate. In many cases, the relationship among related taxa is key to unraveling the evolution of novel adaptations or characteristics by providing a reliable estimate of homology vs analogy / plesiomorphy vs apomorphy. I routinely utilize phylogenetics as a tool and a line of evidence towards a total-evidence resolution of a particular research question.
There are many new species awaiting discovery and description, this is especially true for marine invertebrate animals. Molluscs are one of the most diverse living animal phyla and dozens of new species are being described on a weekly basis, forming a basis for documenting their biodiversity. I myself often encounter species new to science during my expeditions. Being (partly) a taxonomist, I attempt to describe as many of them as possible, because species without names are difficult to rationalise and conserve. When possible, I include molecular phylogenetic analyses to ascertain the morphological identification and placement.
Three large peltospirid deep-sea vent endemic gastropods
Deep-sea Conservation
With the progression of deep-sea exploration technology, mining the deep seafloor for minerals have become a real possibility. However, targeted environments such as polymetallic sulfides in hydrothermal vents and cobalt-rich crusts are still not well studied due to the great expenses associated with deep-sea research. In fact perhaps only 10% of the seafloor have been mapped by mankind and far less have been sampled for biology. No well-agreed protocol for environmental assessment are in place, and we still lack key evidence for inferring the potential damage of deep-sea mining. Part of my research aims to improve our understanding of the potential impacts, in a world where economic and political pressures to exploit the seabed are quickly advancing.
Kairei vent field in the Indian Ocean is one of the vent fields under licenses for mineral exploration issued by the International Seabed Authority for polymetallic sulfides