Effects of depth and overgrowth of ephemeral macroalgae on a remote subtidal NE Atlantic eelgrass (Zostera marina) community. (April 2022)

• Record Type: Journal Article
• Authors: Baden, Susanne; Fredriksen, Stein; Christie, Hartvig; Eriander, Louise; Gustafsson, Camilla; Holmer, Marianne; Olesen, Birgit; Thormar, Jonas; Boström, Christoffer
• Is Part Of: Marine pollution bulletin. Volume 177(2022)
• Publication Date: 2022-04
• Subjects: Zostera marina species components -- Water and sediment biogeochemistry -- Ecological interactions -- Aquaculture and fishery -- NE Atlantic; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2022.113497
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: We conducted a short-term field sampling complemented with time integrating stable isotope analysis to holistically investigate status and ecological interactions in a remote NE Atlantic Zostera marina meadow. We found high nutrient water concentrations, large biomass of fast-growing, ephemeral macroalgae, low abundance, and biodiversity of epifauna and a food web with thornback ray (Raja clavata) as intermediate and cod (Gadus morhua) as top predator. We observed no variation with increasing depth (3.5–11 m) except for decreasing shoot density and biomass of Zostera and macroalgae. Our results indicate that the Finnøya Zostera ecosystem is eutrophicated. During the past three to four decades, nutrients from aquaculture have steadily increased to reach 75% of anthropogenic input while the coastal top predator cod has decreased by 50%. We conclude that bottom-up regulation is a predominant driver of change since top-down regulation is generally weak in low density and exposed Zostera ecosystems such as Finnøya. Highlights: Zostera marina species components Water and sediment biogeochemistry Ecological interactions Aquaculture and fishery NE Atlantic