The Restoration of Diverse Sea Meadows

February 2014

The Restoration of Diverse Sea Meadows

Link: http://www.sciencedaily.com/releases/2014/02/140221184758.htm

     A new study shows that placing seedpods in a pearl net, tethered by a rope but still able sway with the tides, may be an especially effective way of restoring eelgrass meadows. "The resulting crop of eelgrass grown for this study was as genetically diverse as the beds from which the seeds were harvested, which San Francisco State University researchers say can make restoration efforts more likely to succeed." Because eelgrass meadows are threatened by a number of human activities, effective restoration plans that maintain diversity are more likely to succeed. Genetic diversity is a relatively new concern in ecosystem restoration projects, where there has been a clear necessity to move plants and animals back into an area as quickly as possible.
     But, eelgrass restoration projects are challenging because it is not easy to plant seedlings under the water, and seeds scattered over a large area have a good chance of being washed away from the restoration site. Instead, Romberg Tiburon Center researchers tested the Buoy Deployed Seeding (BuDS) restoration technique. To begin, the team harvested eelgrass seedpods from several eelgrass beds in San Francisco Bay. Then, they suspended the pods within floating nets over experimental tanks (called mesocosms) supplied with Bay water and with or without sediment from the original eelgrass areas. As the seeds inside each pod ripened, they fell out of the nets and began to grow in the tanks.
     "The researchers then examined "genetic fingerprints" called microsatellites from the plants to measure the genetic diversity in each new crop." This being just one of the many ways to measure genetic diversity. Based on these measurements and others, the new crops were nearly as genetically diverse as their parent grass beds. The research found that the offspring had remarkably maintained the genetic diversity and distinctiveness of their source beds in their new mesocosm environments at the RTC-SFSU lab.

     "Sea grass meadows are a key marine environment under siege. In their healthy state, they stabilize coastal sediment and provide a huge nursery for a variety of algae, fish, shellfish and birds." However, a variety of human influences such as bridge building, runoff pollution and smothering loads of sediment have threatened these grass beds on a global level.