Bright future ahead for Nemo and friends

Untitled1

A jellyfish in the Waikiki Aquarium in Honolulu, Hawaii. Photograph taken by Lyndsey Tanabe.

 

To kick off the new year, Jennifer M. Sunday and her research team from around the world joined together to develop new methods in predicting how marine organisms might adapt to the increasingly acidic conditions of the ocean.  The accelerating levels of carbon dioxide CO2 and acidification pose a global threat to the diversity of marine organisms, but it is also believed that some species might have the capability to adjust to these conditions through evolutionary change.  With the increasing use of fossil fuels, CO2 emitted into the atmosphere is absorbed into the ocean, where chemical reactions occur that lower pH levels, making the seawater increasingly acidic.

The article published  in the journal Trends in Ecology & Evolution goes beyond looking at the short term adjustments that organisms are capable of using to adapt, but also heritable characteristics that are derived from natural selection.  The article states that “a global research effort is underway to understand the potential impacts of global change on species’ physiology and overall fitness and to consider the broader impacts on biodiversity and ecosystem function”.  Marine fish provide about 15% of all animal protein consumed by humans, so ocean acidification has the capability of decreasing food security.  This study is revolutionary because it looks further into the future at how organisms will react to changing conditions, which depends on their abilities to adapt to acidification.

Sunday and her colleagues have investigated natural selection by using DNA sequencing to identify genes that are responsive to CO2 changes. By using this technique, scientists are able to determine the order of molecules that make up DNA.  The researchers are able to relate genetic variation to fitness, suggesting increased survival potentials.   Recent advances in DNA sequencing have become a cost-effective method to develop data that can be useful towards identifying areas of the genome that are responsive to CO2 change.  A genome is the entirety of an organism’s hereditary information.

Other experiments were conducted; one of which utilized simple marine animals called unicellular plankton, due to their short generation time.  An important finding was that after hundreds of generations of being exposed to  elevated CO2, adverse responses to ocean acidification declined.  Experiments where groups of organisms are bred under controlled acidic conditions mimic hundreds of years of the natural selection process.

The work done currently suggests that evolutionary adaptation to ocean acidification is a possibility.  In every experimental evolution study in which levels of CO2 was a variable there was an adaptive response from the organism.  The next question to investigate is whether these adaptations can occur fast enough to maintain steady populations.  It is harder to study organisms with longer reproductive rates so methods are being considered in an effort to predict their rate of adaptation.  The unprecedented rates of acidification in the ocean environment is a cause for concern and remains an important topic of research to predict what its sum of effects could be.

 

For more information please visit the journal article here.

 

Journal Reference:

Jennifer M. Sunday, Piero Calosi, Sam Dupont, Philip L. Munday, Jonathon H. Stillman, Thorsten B.H. Reusch. Evolution in an acidifying oceanTrends in Ecology & Evolution, 2014; 29 (2): 117 DOI: 10.1016/j.tree.2013.11.001

About Lyndsey