A proof of concept for inland production of the “sea-vegetable” Ulva compressa in Brandenburg (Central Europe) using regional saline groundwater

Abstract

Global food security is a major challenge of this century as pointed out in the UN sustainable development goal (SDG) 2 for creating a world without hunger and malnutrition by promoting among others sustainable consumption and production pattern (SDG 12). With shrinking environmental resources there is a pressing need for alternative food sources such as edible macroalgae (“sea vegetables”). In recent years different research initiatives attempt to develop cultivation providing available freshly harvested macroalgal biomass in inland areas. In this context natural saline groundwater (brine) provides a promising solution for the cultivation of marine organisms. Here we tested firstly the suitability of regional brine from the area Brandenburg (Central Europe) for the indoor cultivation of two edible macroalgae (“sea vegetables”) the chlorophyte Ulva compressa (flat gut weed, also formerly known as Enteromorpha sp.) and the rhodophyte Ceramium virgatum (formerly known as C. rubrum). For the evaluation of brine-based media, we considered different life stages of the macroalgae (e.g., spores, germlings and reproductive thalli) determining differences in their growth rates and nutritional composition (e.g., carotenoid, chlorophyll, and fatty acid concentrations). Brine based media supported macroalgae growth and development, with differences in growth and nutritional composition depending on macroalgal species and life stage. U. compressa cultivated with brine showed a thallus development and nutritional composition comparable to that of specimen cultivated in commercial media. In contrast, results for C. virgatum were less conclusive, due to an overall low germination rate ≤ 13 % under experimental conditions. Given the high demand for fresh macroalgal biomass and limited access to costly cultivation media, we suggest that use of natural brine provides a promising approach to foster the cultivation of selected “sea-vegetables” in inland areas including urban places.