Effects of macroalgal blooms on carbon and nitrogen biogeochemical cycling in photoautotrophic sediments: An experimental mesocosm

MARINE POLLUTION BULLETIN

卷:62

Article

Garcia-Robledo, E.¹  Corzo, A.¹ 

[1] Univ Cadiz, Fac Ciencias Mar & Ambientales, Dpto Biol, Cadiz 11510, Spain

关键词: Macroalgae bloom;    Microbenthos;    Microphytobenthos;    Sediment net metabolism;    Microelectrodes;    Intertidal sediments;   

DOI  :  10.1016/j.marpolbul.2011.03.044

来源: Elsevier

【 摘 要 】

The effects of floating macroalgae (250 g DW m(-2)) on photoautotrophic microbenthos were studied in a flow-through mesocosm with a parallel mesocosm without macroalgae serving as Control. Vertical microprofiles of O-2 at the sediment-water interface showed a immediate and complete suppression of photosynthetic activity of microphytobenthos (MPB) under the macroalgal canopy, resulting in a shift of benthic metabolism from autotrophic to heterotrophic. MPB abundance and chlorophyll a content decreased and a change from a diatom-dominated to cyanobacteria-dominated community was observed. Inorganic nitrogen nutrients concentrations increased in the porewater as a result of the inhibition of MPB nutrient demand, leading to an increase in net ammonification and anaerobic NO; consumption rates. No organic matter transfer from macroalgae to the sediment was detected, resulting in a net consumption of the carbon and nitrogen stored in the sediment. In consequence, sediment was progressively impoverished in nitrogen, reducing sediment nutrient regeneration. (C) 2011 Elsevier Ltd. All rights reserved.

【 授权许可】

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