KelpRes: Ecological Aspects

Kelp have very unique life cycles that have a very visible sporophyte with 2 sets of chromosomes (diploid, 2N) which produces small spores that become a microscopic gametophyte stage with one set of chromosomes (haploid, 1N). This produces gametes that fuse and produce a sporophyte in a process that repeats itself annually. Laminaria hyperborea (Cuvie) sporophytes produce reproductive areas on their blades (sori) from late autumn to early winter, after which they begin to grow a new blade and shed the old one through the spring.

This annual process is very important for repopulating a kelp forest, because Cuvie spores are not very mobile. Spores can move through the water column using flagella, but are generally only active for 24h so much dispersal may be due to ocean currents. Gametes also produced pheromones, or chemical attractants, to draw male to female gametes for fertilization. This complex life cycle allows both for sexual recombination (increasing genetic diversity of a population) and mass production of the products of sex (through sporophyte populations).

We aim to describe the reproductive effort of Cuvie in Ireland, and examine natural populations of microscopic algal stages in kelp forests habitats to better describe the function of this species across Ireland. Annual storms naturally clear areas within kelp forests that allow new sporophytes to repopulate the region, and this occurs throughout the year. Because there is an annual cycle of reproduction, we aim to describe patterns of dormancy, or arrested development, in the kelp spores that repopulate habitats year round.