The Distribution of Fucoid Macroalgal Biomass Along Central Coastal Maine

Abstract

A randomized sampling program was employed to determine macroalgal biomass along 620 km of shore line in Lincoln County, Maine. Total fresh weight tonnage of Ascophyllum nodosum and Fucus spp. was 39,000 and 9300 metric tons, respectively, for mean densities of 63 and 15 kg linear m of shore line-1. Mean fucoid density per unit stable rocky substrata in the fucoid zone was 8.0 kg fresh wt m-2. Biomass was extremely variable along this coast and was concentrated in areas having moderate exposure and large amounts of stable substrata. In a graphic model, wave exposure and the availability of substrata suitable for attachment were used to describe major biomass distributions. Much of this highly invaginated coast was very wave sheltered, producing areas which had decreased fucoid biomass due to ice abrasion and the lack of rocky substrata. Ascophyllum dominated fucoid biomass in sheltered areas, while Fucus reached high biomass levels only in exposed localities. Ascophyllum and Fucus contained large pools of C and N along this 620 km shore line (4.4 .times. 10-6 kg C and 1.5 .times. 105 kg N). Ca and N pools may be functionally important to coastal areas in Maine where invaginated shorelines produce intimate contact of large intertidal regions with relatively small volumes of water. Assuming one biomass turnover per year, combined net primary productivity for A. nodosum and Fucus was 4.4 .times. 106 kg C yr-1.