Like most aquatic vegetation, kelp is being negatively impacted by climate change. Warming ocean temperatures have led to shorter growing and harvesting seasons, including for sugar kelp, one of the most commonly farmed kelp species. The loss of kelp populations can significantly impact ecosystems, and potentially the growing demand for sustainably farming food, feed, fertilizer, medicine, and cosmetics.
To give kelp a chance against climate change, scientists from theWoods Hole Oceanographic Institution (WHOI) have identified kelp species with natural adaptations to cope with heat. In a new study published in the Journal of Applied Phycology[RM1] , WHOI experts identify new strains that could prove to be more resilient in warmer waters.
Researchers first assessed the heat tolerance of kelp gametophytes, the microscopic male and female stages that fertilize and produces kelp blades. Gametophytes were isolated from 14 different populations collected from nearshore waters between New York and Maine. Prior to testing their tolerance to temperatures as high as 24°C (75°F), these were grown in a lab environment for 4.5 years until the second round of research.
In the second round of research, gametophytes that were more heat tolerant were crossbred with other, more heat tolerant strains. At the same time, strains with lower heat tolerance were crossbred. Researchers then tested the heat resistance of their offspring (kelp blades) in a controlled environment.
“There is genetic diversity among sugar kelp populations, so it’s likely that some kelp may already have useful adaptations to cope with warmer temperatures,” said Sara Gonzalez, a guest investigator in WHOI’s Applied Physics and Ocean Engineering Department and lead author of the study. “We found that when we crossed gametophytes that we identified as heat-tolerant, they produced kelp blades that grew better under heat stress compared to the offspring of gametophytes that were not heat-tolerant. This is an important step toward understanding how to breed heat-tolerant kelp andhelping kelp farmers increase reliability in their yields in warming ocean waters.”
This study area focused on strains found in the Northeastern U.S., where kelp beds are declining, and in some cases, no longer growing. This is particularly important to note in the Gulf of Maine, which is the fastest-warming body of water in the world. Productive kelp farms here play a role in the fight against global warming, acting as a carbon sink by sucking up carbon dioxide from the oceans. Kelp can also elevate pH levels in their immediate surroundings and supply oxygen to help mitigate the local effects of ocean acidification.
“Kelp is incredibly versatile. It can also be converted into new fuel sources and can potentially reduce greenhouse gasses and our dependence on fossil fuels,” said WHOI’s Scott Lindell, a research specialist in aquaculture technology and co-author of the study. “In a hotter and drier world of the future, it will be hard to find a better resource for biofuels than farmed seaweed. This study allows us to accelerate the breeding of heat-tolerant kelp strains, thus helping sustain the industry. “
“Future research could address whether one kelp parent transfers more heat tolerance to their offspring,” Lindell continued. “A larger sample size and further work could also show which part of kelp genes is related to heat tolerance.”
