Protecting seagrass through collaboration

By now you’re probably wondering where the pantyhose and fertilizer come in. Like all plants, seagrass needs nutrients to grow, but too much can be a bad thing. Chemical runoff from agriculture and other human development can cause algae to bloom and the seagrass to die, which in turn harms the many creatures that depend on seagrass.

Myself and a diverse group of collaborators, including The City of Surrey, Ducks Unlimited Canada, the Friends of Semiahmoo Bay Society, the University of British Columbia and others from the local community, have partnered to understand how nutrient pollution might harm seagrass. We’re focusing our efforts on Boundary Bay because it’s the largest seagrass meadow in Canada’s Pacific region and is internationally recognized as an important estuary for migratory birds due to its location on the Pacific Flyway. More than 1.5 million birds visit Boundary Bay in the fall and spring. Some ducks and geese eat the seagrass itself, while other birds search for algae and invertebrates living in the seagrass to fuel up for their migratory journey.

Ecology experiments with garden fertilizer tied into the foot of a nylon stocking are used in marine ecosystems around the world to understand how human-caused nutrient enrichment can upset the delicate balance of species interacting in these environments. It’s an old trick of the trade, passed down to me by my PhD advisor Peggy Fong and taught to her by influential restoration ecologist Joy Zedler.

The nylon-enclosed fertilizer is anchored within the seagrass habitat. The nutrients contained in the fertilizer show us what is likely to happen if too many nutrients flow into a seagrass bed. Once a month, we return at low tide, often in the middle of the night, to collect samples from the meadow. The great thing about our experiment is that the fertilizer only works on a small area and doesn’t have any lasting impacts. This is not true when large amounts of nutrients flow into coastal environments from human development and agriculture.  

Back in the lab, the samples collected from Boundary Bay are processed by a team of scientists, secondary school students, and undergraduates. Seagrass, algae, and animals are separated from each other and counted. After the invertebrates are removed from the plants and mud, a highly trained entomologist, Dr. Felipe Amadeo, uses a powerful microscope to identify each species.

Through this work, we’ve been able to discover just how many invertebrate species live in Boundary Bay. An area the size of your laptop can be home to over 40 different species and 4,000 individual invertebrates! Even though most of us will never see these invertebrates, they are very important links in the food chain. Take the shrimp-like amphipod, only five millimetres long, that pollinates seagrass flowers, much like bumblebees in your home garden. Or the isopod that sticks to a blade of seagrass and roams around to eat tiny algae. Both are important diet items for commercially valuable fish like the herring and juvenile salmon. 

All this information is being used to establish water quality criteria, research plans, and regular monitoring protocols to protect the incredible biodiversity of Boundary Bay.