Fatty Acids, Estuarine Biofilm and Migratory Waterfowl
The following article was published in the journal "Frontiers in Marine Science" in February 2020. It draws attention to the important ecological role of Fatty Acids produced by the biofilm formed on inter-tidal areas of estuarine mudflats. The exciting new research findings prove the critical importance of Fatty Acids for migratory shorebirds during their fall and spring migration. Migratory shorebirds, in particular, appear to depend on this powerful dietary asset to stock up on energy needed for their long-distance flights from summer to winter ranges and return. Western Sandpiper as prime example travels from Northern Canada to Peru and beyond following their breeding season.
The findings by the authors of this article support CERCA's efforts in restoring the ecological integrity of the Cowichan Estuary, one of the most important estuaries in BC. The research findings will also enrich CERCA's educational guided mudflat walks and support our pledge to protect the mudflats against grounding out log booms, dredging, and other adverse impacts that destroy and prevent biofilm to form, especially in areas of grounding out log booms. Within this context, I would like to draw your attention to links related to previous mudflat publications on CERCA's website.
http://www.cowichanestuary.com/nature-trail-part-3-mud-flats/
http://www.cowichanestuary.com/guided-mudflat-walks-2019/
CERCA is now in the process of teaming up with the researchers by becoming part of the Motus Wildlife Tracking System (MOTUS) currently being established along the Pacific coast from Alaska to South America to learn more about the ecology of migratory birds and their relationship with estuaries. Exciting news indeed!
Below the abstract of the referenced article. For the full article check the February 2020 edition of the Journal "Frontiers in Marine Science". Happy reading!
Dr. Goetz Schuerholz, Chair CERCA
Abundance of Fatty Acids From Intertidal Biofilm in Relation to theBreeding Migration of Shorebirds
Peter J. Schnurr1, Mark C. Drever2*, Robert W. Elner2, John Harper3 and Michael T.Arts1
1 Department ofChemistry and Biology, Ryerson University, Toronto, ON, Canada, 2 Environment &Climate Change Canada,
Delta, BC, Canada,3 Coastal & Ocean Resources, Victoria, BC, Canada
Intertidal biofilm is a thin layer of microbes and meiofauna enmeshed inan extracellular polymeric matrix within and on top of mudflat sediment. Thismedium provides a dynamic resource for a variety of consumers in estuarinehabitats, and is rich in essential fatty acids that birds require forlong-distance migration. We measured seasonal changes in biofilm fatty acidcontent from spring to summer on the Fraser River Estuary, one of the richestand most important ecosystems for migrant and wintering waterbirds in Canada.Fatty acid content in biofilm showed a strong seasonal pattern with a peak inthe spring that is associated with the northward migration of WesternSandpipers (Calidris mauri) to their breeding grounds. This peak is linked to theabundance and physiological state, and hence nutritional condition, of epipelicdiatoms, which, in turn, depend on a combination of mudflat topography,salinity,
temperature, and nutrients that can fluctuate widely with the freshwaterinputs from the Fraser River. Specifically, areas with higher elevation (i.e.,_1 m) had longer periods of exposure to ambient conditions (i.e., light, warmtemperatures, gas exchange into/out of biofilms) that facilitated more biofilmgrowth and higher fatty acid content. Moreover, springtime changes in waterchemistry (i.e., salinity/osmotic stresses and nutrients) and temperaturefacilitated the production of higher overall total lipid/fatty acid contents inthe mudflat biofilms compared to summer. Effective conservation of migratingshorebirds depends on the protection of underlying processes at importantstopover sites that promote biofilm communities to escalate their production oflipids, including essential fatty acids, during key times of the year.