Effects of macroalgal blooms on carbon and nitrogen biogeochemical cycling in photoautotrophic sediments: an experimental mesocosm.
Effects of macroalgal blooms on carbon and nitrogen biogeochemical cycling in photoautotrophic sediments: an experimental mesocosm.
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DOI：
10.1016/j.marpolbul.2011.03.044
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发表时间：
2011-07
影响因子：
5.8
通讯作者：
E. García-Robledo;A. Corzo
中科院分区：
文献类型：
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作者：
E. García-Robledo;A. Corzo
在流通式微生态系统中，以不含大型藻类的平行微生态系统为对照，研究了浮游大型藻类(250g DW m−2)对光自养微底栖动物的影响。沉积物-水界面上O2的垂直分布表明，大型藻类冠层下的微型底栖植物(MPB)的光合作用活性立即受到完全抑制，导致底栖生物代谢从自养向异养转变。MPB丰度和叶绿素a含量下降，群落由硅藻为主向蓝藻为主转变。由于MPB营养需求的抑制，孔隙水中无机氮营养物质的浓度增加，导致净氨化作用和厌氧NOx消耗率增加。没有检测到从大型藻类到底泥的有机物转移，导致底泥中储存的碳和氮的净消耗。结果，沉积物中的氮逐渐贫化，减少了沉积物营养物质的再生。
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 x-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.