.jpg)
The growlines were in the water and ready for the kelp seed. 🙌
While the deployment of our arrays had been delayed, the readiness of our kelp seed was too. During our applications review, we were informed by Woods Hole Oceanographic Institution (WHOI) that our seedspools would be ready for pickup a month later than planned – due to a change in how the seedspools were being developed. Seedspools are commonly derived by inoculating seedstrings amidst a soup of sea water and reproductive kelp tissue. The tissue releases kelp spores that settle and grow on the string. This method is referred to as meiospore release, and relies on having reproductive kelp tissue that’s been freshly harvested from the wild**.** However, due to particularly warm water temperatures, the hatcheries working with WHOI had found it difficult to find reproductive tissue for this purpose. WHOI would therefore take an alternate approach to developing the seedspools: deriving them from gametophyte cultures.
Gametophyte?
Kelps have a two-part life cycle: 1) a large visible stage called the sporophyte phase, and 2) a microscopic stage called the gametophyte phase. In the sporophyte phase, mature kelp fronds emit spores from their reproductive “sorus” tissue. These spores will eventually turn into male and female gametophytes. This is the sexual phase, and these male and female gametophytes will reproduce to create new sporophytes – aka new kelp.
<aside> 💡 The explanation above is an arguably too short summary of seaweed reproduction (fyi, other nonvascular plants – mosses, liverworts, hornworts – make babies like this too). For a comprehensive version, check out the Kelp: Biology section of the New England Seaweed Culture Handbook.
</aside>
Gametophyte cultures?
WHOI has a sort of gametophyte bank – the product of spores (originating in parental kelp tissue from southern New England sites including Cape Cod, Rhode Island and Connecticut) that have been cultivated in the lab, isolated as male and female gametophytes, and grown into large clonal masses wherein each cell is genetically identical. These male and female gametophyte biomasses are the gametophyte cultures, and may be maintained and stored indefinitely. When ready for use, the male and female cultures are combined and sprayed onto the spooled string for seeding.
<aside> ☝ Again... an abbreviated version of a fascinating, novel, and important process; as wild kelp beds are becoming more scarce, cultivation methods that reduce dependence on wild stocks are key. Moreover, such methods may (additional research is needed on this front) allow for more controlled and consistent seeding. Efforts to optimize kelp seed cultivation merit an entire post, and I’ll be covering the matter in the future. Until then, see the Kelp: Isolation and Maintenance of Vegetative Cultures section of the Seaweed Culture Handbook, for all the juicy, gametophyte culture deets that I skipped.
</aside>
WHOI generously gave us two seedspools instead of one, to ensure enough seedstring for both 100ft growlines. These spools were from WHOI’s first batch using the gametophyte culture method, and didn’t look like much – short pieces of PVC pipe, wrapped with string and shaggy, brown, plant matter. That said, after studying kelp and seaweed farming from afar, for the better part of a year, having these soggy spools in hand was awesome. They were then wrapped in wet paper towel and popped in a cooler. They’d be traveling just 20 minutes up the coast to our growlines, to begin their winter-long dip in the Atlantic.
One of the seedspools, after the first one was used up (the bare tube on the right). Of course I forgot to take better pictures, prior to outplanting. Too excited.
🏡 Home