Study Reveals Effect of Climate Change on Growth and Metabolism of Lobsters

According to a recent study reported in the Ecology and Evolution journal, the American lobsters may be more vulnerable to the effects of climate change than previously believed. These species support the most precious fishery in North America.

This latest discovery may allow fishery managers to expect the impacts of a prolonged climate change for one of the country’s most valuable natural resources.

The range of the American lobster stretches from Atlantic Canada to the mid-Atlantic waters of the U.S.; however, increased emissions of carbon dioxide by people are acidifying and warming the ocean habitat in these species.

So far, research conducted on the early life phases of lobsters has surmised that ocean acidification, when compared to warming, had a comparatively reduced effect on metabolism and growth. But the genes of these lobsters tell a different story, according to the recent publication.

Our study indicated that acidification is affecting these lobsters on a molecular scale. Because of environmental changes, they have genes firing at an even higher rate.

Maura Niemisto, Study Lead Author and Research Associate, Bigelow Laboratory for Ocean Sciences

Niemisto collaborated with David Fields, a Senior Research Scientist from Bigelow Laboratory, and Richard Wahle, a Research Professor from the University of Maine and based at the Darling Marine Center, to publish the study.

Co-authors of the study, Spencer Greenwood from the University of Prince Edward Island, and Fraser Clark from Dalhousie University, contributed their know-how in genomics. The study was based on prior experiments performed by co-author Jesica Waller from the Maine Department of Marine Resources.

Genes allow all living organisms to control a host of biological processes. This can be influenced by variations in their environment. For instance, a heat shock protein gene is found in several organisms. When the organisms get overheated, the environmental stress stimulates cells to synthesize a protein that allows the creatures to adapt.

The research work targeted the postlarval stage of lobsters, because these creatures dwell in the upper column of water, in which acidification and temperature of the oceans are fluctuating rapidly. Besides this, the lobsters are planktonic, which implies that they have minimal control of their movement to prevent adverse surroundings.

Laboratory experiments were performed by the researchers to subject the postlarval lobsters to the acidity and temperature levels forecasted for the century end. Within such conditions, the researchers found that lobsters’ cells modified the regulation of genes to support their immune functions and shell structure.

This was a stronger response with respect to higher acidity than to higher temperatures. The research work also demonstrated that when the lobsters’ environment was both acidic and warm, the creatures displayed a considerably more genetic reaction than when subjected to either stressor alone, that is, high acidity and high temperatures.

“Stressors on an organism have the ability to compound into something that makes it really hard to grow through all the developmental stages to get to a full-grown lobster, ” added Niemisto, who performed the study as part of her master’s dissertation in marine biology at the University of Maine.

The consequences of such responses continue to remain vague for lobsters living in the Gulf of Maine, which is warming and acidifying much faster than many of the oceans in the world.

While the study results indicate that lobsters have the genetic ability to acclimatize to their varying environment, it may come at a price. This is because the genetic processes take a considerable proportion of energy, which comes from limited funding.

So, if they're spending a lot of energy on building proteins to respond to stressors, something else has to give.

Maura Niemisto, Study Lead Author and Research Associate, Bigelow Laboratory for Ocean Sciences

At present, scientists are exploring ways to find out where that additional energy is actually coming from and what is exactly being given up. For instance, if lobsters have to spend their energy on sustaining their shells, they would be unable to invest in their immune system.

According to the study authors, the subsequent step is to gain a deeper understanding of these genetic reactions with respect to changes at a larger scale. Combining this study results with additional studies on the biology and ecology of lobsters can help explain their possible response as a population.

This study has cracked open the door to our understanding of the basic biology of lobster larvae and their response to the changing environment,” said co-author Fields. “However, there is still a lot to learn. As the use of these genetic tools grows, so will our understanding of the larval lobster biology and the impact of climate change on this iconic fishery.

David Fields, Senior Research Scientist, Bigelow Laboratory for Ocean Sciences

The study was funded by Ocean Acidification and National Sea Grant programs of the National Oceanic and Atmospheric Association and by the National Science Foundation.

Journal Reference :

Niemisto, M., et al. (2020) American lobster postlarvae alter gene regulation in response to ocean warming and acidification. Ecology and Evolution. https://doi.org/10.1002/ece3.7083.