Potential uptake of dissolved organic matter by seagrasses and macroalgae

Marine Ecology Progress Series

Karline Soetaert¹  Miguel Lara¹  Tjeerd J. Bouma¹  Edward P. Morris¹  Fernando G. Brun¹  Iris E. Hendriks¹  Tom Van Engeland¹  Gloria Peralta¹  Jack J. Middelburg¹ 

关键词: Uptake;    Dissolved organic nitrogen;    Stable isotopes;    Zostera noltii;    Cymodocea nodosa;    Caulerpa prolifera;    Seagrasses;    Macroalgae;   

DOI  :  10.3354/meps09054

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Dissolved organic nitrogen (DON) acts as a large reservoir of fixed nitrogen. Whereas DON utilization is common in the microbial community, little is known about utilization by macrophytes. We investigated the ability of the coexisting temperate marine macrophytes Zostera noltii, Cymodocea nodosa, and Caulerpa prolifera to take up nitrogen and carbon from small organic substrates of different molecular complexities (urea, glycine, L-leucine, and L-phenylalanine) and from dissolved organic matter (DOM) derived from algal and bacterial cultures (substrates with a complex composition). In addition to inorganic nitrogen, nitrogen from small organic substrates could be taken up in significant amounts by all macrophytes. Substrate uptake by the aboveground tissue differed from that of the belowground tissue. No relationships between carbon and nitrogen uptake of small organics were found. The preference for individual organic substrates was related to their structural complexity and C:N ratio. Uptake of algae-derived organic nitrogen was of similar magnitude as inorganic nitrogen, and was preferred over bacteria-derived nitrogen. These results add to the growing evidence that direct or quick indirect DON utilization may be more widespread among aquatic macrophytes than traditionally thought.

【 授权许可】

Unknown