Water Transport May Lead to Unpredictable 'New' Marine Species, Evolutionary Consequences

If you think water transportation's only potential risk to the environment is through its fuel consumption, think again. A recent study led by the University of Southampton says possible new evolutionary trajectories may happen, primarily attributing the event to shipments, that may later on produce "new" species and a different kind of global change.

University of Southampton's PhD Student Jamie Hudson, together with her colleagues, have published a scientific paper in the Journal of Biology Letters regarding their findings on the effects of anthropogenic transport to the world's biological resources. Focusing on a tunicate species Ciona intestinalis, the researchers tried to identify whether human transportation in aquatic ecosystems also induce transport of different tunicates from geographically isolated populations.

Their method included gathering of specimens from different parts across the English and French coasts. All in all, they have genotyped 484 individuals. The researchers then carefully looked for the micro-satellites, which are DNA sections required to help in the determination of the specimen's relationship or similarity to other populations.

"We found that C. intestinalis from some locations exhibited a shuffling of genetic material, as expected by human-mediated transport (boats can travel further distances than the larvae). However, unexpectedly some of the populations exhibited the opposite pattern (some populations were not genetically similar), despite there being evidence of artificial transport between these locations -- this may be due to natural dispersal or premodern population structure," Hudson stated in an article.

"Marine species are expected to develop populations whereby geographically close populations are more genetically similar than geographically distant populations. However, anthropogenic (environmental change caused by humans) activities such as shipping promote the artificial transport of species and bring distant populations together, leading to the crossing of individuals and therefore genetic material. The disruption of pre-modern genetic patterns through anthropogenic activities is an unprecedented form of global change that has unpredictable consequences for species and their native distributions," she added.

Furthermore, their team concluded that human transport has already altered evolutionary trajectories. However, some other factors were also considered to aggravate the situation such as the complementary natural patterns of dispersal working unintentionally together with human-induced actions.