School of herring
Herring is one of few species whose genetic variation is repeatedly analysed in the national environmental monitoring. A lot of genetic variation increases the chances that species can adapt to changing environmental conditions and survive into the future.
Photo: Anders Salesjö

Genetic diversity important for protecting the marine environment


This week, researchers and authority representatives gather to discuss how genetic diversity can be included in the protection of the marine environment.
– Knowledge of genetics and evolution is essential for developing our management, says Jakob Granit, Director General of the Swedish Agency for Marine and Water Management, who is participating in the conference at Tjärnö marine laboratory.

Marlene Janke
"Evolution has a lot to offer when it comes to the problems that climate change are bringing", says Marlene Jahnke, researcher at the Department of Marine Sciences.
Photo: Per Moksnes

Protecting species, such as eelgrass, cod or reef-building corals, is what is most often associated with biodiversity conservation efforts. A growing body of research now suggests that an important part of this work is to protect and conserve the genetic characteristics within species, i.e. the genetic diversity.

Genetic diversity can be seen as a kind of toolbox, where different hereditary traits can be put to good use, now or in the future. The more diversity a species has in its "box", the better it is prepared to adapt to environmental changes of various kinds.

"The genetic makeup says a lot about the ability to adapt to new environmental conditions. For example, how likely it is that a species can survive in a changing climate, or the likelihood that non native species will spread to new areas", says Marlene Jahnke, researcher at the Department of Marine Sciences.

Taking genetic variation into account

The rapid development of methods to investigate and map the genetics of individuals as well as entire species, has opened up entirely new possibilities. 

"For example, we can see how species are divided into populations that are genetically different and may therefore need to be managed differently. A typical example is cod, with coastal and offshore stocks. These have different characteristics that may need to be taken into account", says Marlene Jahnke.

Other situations where genetic information can be valuable are when ecosystems are to be restored or given some kind of area protection. Here, Jahnke draws examples from her own research on eelgrass meadows:

"In the sea off Marstrand, large areas of eelgrass have disappeared since the 1980s. We have investigated how much genetic diversity there is in the eelgrass meadows that remain, and also the extent to which different meadows are connected and can disperse."

"High genetic diversity and good connectivity between meadows is an indication that there is a chance of long-term survival. Such eelgrass meadows may be worth protecting, for example as a Natura 2000 site, and may also provide transplants for neighbouring and genetically similar meadows that need restoration."

Evolution offers solutions

Recently, genetic variation of a few species has been included in the national environmental monitoring programme. A decrease in genetic variation is a signal that action is needed. Depending on the species, this could mean restricting fishing, setting up a nature reserve, or reducing eutrophication in an area.

Centre for Marine Evolutionary Biology, CeMEB, is organising a conference on marine evolution and conservation biology this week. In addition to scientists, the conference will be attended by representatives from county councils and other authorities. The responsible authority for the monitoring of genetic diversity is the Swedish Agency for Marine and Water Management, and Director General Jakob Granit is invited speaker.

Director General for the Swedish Agency for Marine and Water Management, Jakob Granit
Director General of the Swedish Agency for Marine and Water Management, Jacob Granit.<br /> Photo: Kristin Lidell
Photo: Kristin Lidell

"Knowledge of genetics and evolution is essential to develop our management towards measures and monitoring that ensure the resilience and viability of species and habitats - not least given the impact of climate change on aquatic organisms and the expectations of a developed blue economy," says Jakob Granit.

The scientists organising the conference usually focus on fundamental questions of evolution, genetics and mechanisms of natural selection.

"But we have realised that evolution has a lot to offer when it comes to the problems climate change are bringing. There is still a lot of work to be done to develop methods for this, but I don't see any other way", says Marlene Jahnke.

Text: Susanne Liljenström