August 3, 2010

Biology in Paradise

Assistant Professor of Biology, Queens College and The Graduate Center

Tomorrow, I depart with three biology students for the French Polynesian island of Moorea. Paul Gauguin went to the island next door–the larger and better known Tahiti–to paint. We are going to Moorea and its surrounding waters as part of an international project to examine the entire biological community at the DNA level.

Professor Hickerson with his students by Hudson river in Manhattan

Professor Hickerson with his students by Hudson river in Manhattan

Specifically, at least three individuals from every species of animal, plant and fungi are being collected and DNA sequenced at a gene that is particularly easy to detect across such a massive taxonomic scale. This is referred to as “DNA barcoding” or DNA biocoding, and ultimately the aim is to collect this type of genetic data from every species on the planet. This will be extremely useful for all sorts of applications, ranging from the identification of species to the discovery of new ones; from estimating levels of biodiversity to reconstructing evolutionary history and understanding the dynamics of species invasions.

With “barcodes” on every species, researchers can pioneer whole ecosystem approaches to investigating how food webs change in response to things like sea temperature changes and invasive species, as well as how these food webs were originally constructed when this volcanic island rose from the ocean.

The Moorea DNA Biocode project is a large-scale ongoing operation involving more than 100 ecologists and evolutionary biologists from many institutions, and it is hoped that the work can eventually be scaled up to much larger areas of our planet. The project is being orchestrated at the Gump Research Station run by the University of California, Berkeley, and we will be staying there for the duration of our expedition. My research team includes a CUNY graduate student, J.T. Boehm, and two Queens College undergraduates, Francois Desinor and Chris Ludvik.

Together we will be working on three different ongoing projects. First, we’ll be going all over the island to sample anthropogenic sites like docks and peers to look for invasive marine animals. Although many animals can be easily seen, there can be a multitude of very small animals and/or larvae in water or on structures that can be very difficult if not impossible to identify at the species level if one is not an expert at a wide range of taxonomic groups. However, we can use the “DNA Biocodes” to identify each marine animal and measure “exact” levels of biodiversity with respect to all the different species that are present and all of their relative abundances. Most importantly, we can use the DNA Biocodes to detect invasive species that may have otherwise gone undetected (until it was too late!). These data will be critical for investigating changing food webs dynamics in the context of ongoing drastic climate and oceanographic changes, as well as increases in the species pool due to invasions.

The second project will involve using DNA biocodes to figure out what a particular fish species eats. By collecting the DNA biocodes from materials found in the gut of a fish and comparing these with the DNA biocode database compiled from all species collected on the island, one can quickly  know all the different species a fish ate recently. The fish species we will be focusing on is the banded pipefish (corythoichthys flavofasciatus) which can be found swimming around the abundant coral reefs of Moorea.

Professor Hickerson with his student by Hudson river in Manhattan

Professor Hickerson with his student by Hudson river in Manhattan

In the spring of 2009 we collected potential food species found in the same corals as these pipefish. Normally it is very difficult to get accurate estimates of diet, and if this project works it will finally allow ecologists to get full estimates of food web architecture. The third project will involve using the computational tools i develop to help understand how an entire island becomes occupied by all the species that we find on it today. The Society Islands (of which Moorea is one of many), are formed by a moving “volcanic hotspot” and because the nearby and younger island of Tahiti emerged more recently than Moorea, we can use all the biocode data to reconstruct how species from Moorea colonized Tahiti after it emerged approximately 600,000 years ago.

While the Biocode project is providing the necessary data for answering such large-scale questions, the computational methods I am developing will be able to analyze data from such a large number of species while accounting for the complexity associated with species-specific differences and inherent randomness and messiness associated with using genetic data.

Talk to you in a couple of days…from the South Pacific.