The health of communities of eelgrass, a forest of marine plants in the Pacific and Atlantic oceans, is of concern due to global climate change
By YASH RATHI — science@theaggie.org
On August 1, a new collaboration study between UC Davis and other research institutes was published in the Proceedings of the Journal of the National Academy of Sciences (PNAS). The researchers worked with a community of species called eelgrass, which is a sea plant at the bottom of many coastal food webs found specifically on the North Atlantic and Pacific coasts.
According to the study, eelgrass is commonly found in shallow waters and tropical regions from Baja California to Alaska. This species not only provides food and shelter to marine organisms found in this area, but also provides a plethora of services to humans, including absorbing carbon from water, protecting coastlines from storms, and reducing harmful bacteria in the oceans.
“Here, we explore how the growth form and associated eelgrass community of coastal founding species (sea eel) are shaped by current environmental conditions and a complex history of evolution and dispersal,” study bed. “Eelgrass lives in shallow marine waters of the Northern Hemisphere, from warm temperate regions to the Arctic in the Atlantic and Pacific Oceans.”
However, researchers have found a sudden disappearance of eelgrass from many regions due to rising temperatures in the oceans. A very recent example is seen in the southern region of Portugal, where eelgrass is moving north towards cooler waters. The Atlantic species has less genetic diversity than the Pacific species, making it more difficult to adapt to this sudden change in water temperature.
Jay Stachowicz, Ph.D. is co-author of the study and a professor in the Department of Evolution and Ecology at UC Davis. He underlined the importance of the diversity that is obviously lost in Atlantic species.
“Diversity is like having different tools in your tool belt,” Stachowicz said. “And if all you have is a hammer, you can put some nails in, but that’s about it. But if you have a full range of tools, each tool can be used to perform different tasks more efficiently. »
Through the analysis of genetic data, Stachowicz and his collaborators uncovered the ancient genetic history of eelgrass, which helped them determine its size, location, structure, and the potential organisms that lived among them in the past. Specifically, the genetic data showed how eelgrass survived multiple periods of climate change.
About half a million years ago, eelgrass began its journey to the Atlantic from the Pacific. However, not even half of the organisms were able to reach the Atlantic. Additionally, due to the Pleistocene epoch, a period in which several ice ages occurred, not even 20% of plant species survived.
The surviving seagrass population found in this area has signatures left in its DNA due to this long-lasting struggle during its migration. One of those differences, according to the researchers, is a striking genetic difference in Pacific and Atlantic grasses.
Emmett Duffy, Ph.D., who is the lead author of the study and a sailor biologist of the Smithsonian Environmental Research Centerhelped to better understand seagrass migration.
“The ancient legacy of this Pleistocene migration and eelgrass bottleneck [or decrease in its population size] in the Atlantic had consequences for the structure of the ecosystem 10,000 years later,” Duffy said.
Researchers were concerned about this sudden disappearance of eelgrass and its health. Therefore, they created a global network called the Zostera Experimental Network, or ZEN, which comes from the scientific name for eelgrass. Zoster Marine. With this network, the researchers hoped to bring together scientists from around the world who study eelgrass to develop a clearer overall picture of the health of the species.
Studying the eelgrass community at 50 different sites across the Atlantic and Pacific, the researchers conducted 20 sample plots per site and came up with 1,000 total eelgrass plots to make inferences. The team collected data, including the size of the species and the nutrition available to them.
The most common difference observed in the two regional species of eelgrass was a difference in height. The Pacific Coast variant looked like an underwater forest three to six feet high. In contrast, the Atlantic species were more grassland-like which rarely reached the height of one meter.
Moreover, while only genetics played a very important role in the survival and growth of Pacific species, Atlantic species were influenced by both environmental and genetic factors.
Jeanine Olsen, Ph.D., is co-author of the study and professor emeritus at University of Groningen in the Nederlands. She spoke about the sudden decline in the seagrass population due to the increase in pollution over the past decade.
“I don’t think we’re going to lose [eelgrass] in the direction of extinction,” Olsen said. “It’s not going to be like that. He has a lot of tricks up his sleeve. Global warming in itself is probably not the main threat to eelgrass. Pollution from cities and farms, which can cloud the water and lead to harmful algal blooms, also endangers seagrass beds. That said, the wide range of environments in which eelgrass can survive speaks to its hardiness.
Written by: Yash Rathi — science@theaggie.org
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