Germplasm banking of the giant kelp: Our biological insurance in a changing environment

Abstract

Genetic diversity is being lost at a fast pace — seaweeds are no exception. The giant kelp, Macrocystis pyrifera, forms vast underwater forests in both hemispheres and is a key species for ecosystem functioning. But this species is also a commodity product. M. pyrifera is harvested for its chemical compounds (e.g. alginates) and for feedstock (e.g. abalone). In the past 5years, some companies tried new farming techniques to boost biomass production for biofuel conversion. But the lack of sustainable management can lead to genetic erosion and degradation of livelihoods. Often, the natural genetic populations are not described, and we may be losing what is yet to be found. Aiming to alert and prevent this situation, we developed a germplasm bank based on the genetic diversity of M. pyrifera from Chile. We preserved female and male gametophytes in separate, from 3 genetic populations in low light, at 10°C, in Provasoli media but without cryoprotective agents. After 5years in cold storage, we show for the first time gametophyte viability up to 89% and viability differences between genetic populations. We discuss the benefits of this germplasm bank considering sustainability of seaweed production, food security pressures, and climate change.