by Shep Erhart
The winter solstice is not the usual time of year to plant seeds, nor is the ocean the usual place. But that’s exactly what we were doing this past December 21, 2013, in the cold, gray waters of Frenchman Bay, a few miles from our facility here in Franklin.
Tiny alaria ready to plant out
Biologically speaking, these aren’t exactly seeds, as in the encased male and female genetic material awaiting the miracle of water and warmth to put forth their tender dicotyledon shoot. And seaweeds aren’t actually plants, but that’s another story.
What we “planted” out in the bay were baby seaweeds–tiny kelp (Saccharina latissima) and alaria (Alaria esculenta).
They had been carefully “hatched” in a climate- controlled “seeding” lab, where the spores we had scraped from their parents last summer were encouraged to combine to form miniscule sporophytes that were enticed to attach to some fine twine. That twine, loaded with tiny kelp babies, was then wrapped around a one-inch diameter PVC pipe. This is a fascinating process with many more details that I’ll leave to Sarah Redmond for some other time. Sarah is a Marine Extension Associate focusing on seaweed, based at the University of Maine’s Center for Cooperative Aquaculture Research (CCAR), another partner in seaweed aquaculture efforts.
Kelp-seeded twine wound around PVC
So here’s what happened on the winter solstice: Tollef Olsen from Ocean Approved and I took about a dozen of these twine-wrapped, foot-long pieces of pipe (submerged in cold salt water to reduce shock) out to the thirty-five-acre aquaculture site we are sharing with James West, a Sorrento lobsterman who intends to raise mussels on this site just off Preble Island, in Frenchman Bay. Growing seaweed near nitrogen-producing shellfish or finfish aquaculture sites enhances growth while removing excess nutrients from the water. This is the win/win result of Integrated Multi Trophic Aquaculture, or IMTA. (Want to learn more about IMTA? Check out “Seaweeds–a Part of Everyday Life” from IMTA Canada)
Once we reached the four big yellow mooring markers on the site, we attached the end of a coil of 3/8” sinking rope to one of the mooring lines, about seven feet down. To this we attached the end of a spool of twine, fuzzy and brown with baby kelps.
As I slowly reversed the boat toward the opposite mooring, the rope uncoiled off the rotating drum at the stern of the boat, as the twine spiraled off the PVC spool onto the rope. In this little video you can see it happening, as you listen to the sound of the uncoiling rope drum.
Every 150-200 feet, we stopped and changed spools, and attached a five- pound cement weight at the end of a seven-foot rope and buoy. This keeps the seeded rope stable at a seven foot depth from end to end (approximately 600 feet).
Seven feet is the depth that Tollef has found is optimal for the kelp to have access to light and nutrients at this time of year. Remember that in the wild these plants would be covered by much deeper water than that twice a day. By the end of a couple of hours, we had laid about 1800 feet of rope and spiraled on to it about a dozen spools of twine. These twine spools bore sugar kelp babies from two regionally different parents, as well as some alaria sporophytes hailing from the Downeast area.
“Grown up” kelp, from another site–hopefully what our babies will look like in a few months!
Wow, what a day. We were very grateful to have found an almost perfect weather window, in the midst of what was already a tough winter, to get these tiny plants out into the environment they will hopefully flourish in. These species love cold water so in the winter they have their chance, particularly as the sun gets stronger and the winter upwelling brings them the nutrients they need.
Next: a visit to see how they are doing. Stay tuned. Stay warm.