S. F. Starr, B. Mortazavi, C. Tatariw, K. A. Kuehn, J. A. Cherry, T. Ledford, E. Smyth, A. Griffin Wood, S. E. Sebren
{"title":"易变有机物促进天然和人造海湾沼泽的氮滞留","authors":"S. F. Starr, B. Mortazavi, C. Tatariw, K. A. Kuehn, J. A. Cherry, T. Ledford, E. Smyth, A. Griffin Wood, S. E. Sebren","doi":"10.1007/s10533-024-01128-0","DOIUrl":null,"url":null,"abstract":"<div><p>Coastal marshes mitigate allochthonous nitrogen (N) inputs to adjacent marine habitat; however, their extent is declining rapidly. As a result, marsh restoration and construction have become a major foci of wetland management. Constructed marshes can quickly reach similar plant biomass to natural marshes, but biogeochemical functions like N removal and retention can take decades to reach functional equivalency, often due to lags in organic matter (OM) pools development in newly constructed marshes. We compared denitrification and dissimilatory nitrate reduction to ammonium (DNRA) rates in a 32 year-old constructed marsh and adjacent reference marsh in the Northern Gulf of Mexico. Marsh sediments packed into 3 mm “thin discs” were subjected to three OM quality treatments (no OM addition, labile OM, or recalcitrant OM) and two N treatments (ambient nitrate or elevated nitrate) during a 13 day incubation. We found that OM addition, rather than marsh type or nitrate treatment, was the most important driver of nitrate reduction, increasing both denitrification and DNRA and promoting DNRA over denitrification in both marshes. Fungal and bacterial biomass were higher in the natural marsh across treatments, but recalcitrant OM increased fungal biomass in the constructed marsh, suggesting OM-limitation of fungal growth. We found that constructed marshes are capable of similar denitrification and DNRA as natural marshes after 30 years, and that labile OM addition promotes N retention in both natural and constructed marshes.</p><h3>Graphical Abstract</h3><p>Conceptual figure highlighting the findings of this experiment. Under control treatment with no C addition (bottom panel), constructed and natural marshes have similar rates of both DNRA and denitrification. The natural marsh has higher fungal and bacterial biomass, while fungal biomass is not detectable in the constructed marsh. Under labile OM additions (upper left panel), rates of both DNRA and denitrification are increased and DNRA becomes favored over denitrification in both marshes. Recalcitrant OM additions (upper right) increase denitrification, but do not affect DNRA or % denitrification. The addition of recalcitrant OM also increases the detectability of fungal biomass in the constructed marsh.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":3.9000,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01128-0.pdf","citationCount":"0","resultStr":"{\"title\":\"Labile organic matter promotes nitrogen retention in natural and constructed gulf coast marshes\",\"authors\":\"S. F. Starr, B. Mortazavi, C. Tatariw, K. A. Kuehn, J. A. Cherry, T. Ledford, E. Smyth, A. Griffin Wood, S. E. 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Under control treatment with no C addition (bottom panel), constructed and natural marshes have similar rates of both DNRA and denitrification. The natural marsh has higher fungal and bacterial biomass, while fungal biomass is not detectable in the constructed marsh. Under labile OM additions (upper left panel), rates of both DNRA and denitrification are increased and DNRA becomes favored over denitrification in both marshes. Recalcitrant OM additions (upper right) increase denitrification, but do not affect DNRA or % denitrification. 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引用次数: 0
摘要
沿海沼泽可减轻邻近海洋生境的同源氮(N)输入,但其范围正在迅速缩小。因此,恢复和建造沼泽已成为湿地管理的主要重点。人造沼泽可以很快达到与天然沼泽相似的植物生物量,但生物地球化学功能(如氮的去除和保留)可能需要几十年才能达到功能等效,这通常是由于新建沼泽的有机物(OM)池发展滞后造成的。我们比较了墨西哥湾北部一个建有 32 年的沼泽和邻近参照沼泽的反硝化率和硝酸盐还原氨(DNRA)率。在为期 13 天的培养过程中,将沼泽沉积物包装成 3 毫米的 "薄盘",对其进行了三种 OM 质量处理(不添加 OM、易变 OM 或难分解 OM)和两种 N 处理(环境硝酸盐或硝酸盐升高)。我们发现,添加 OM(而不是沼泽类型或硝酸盐处理)是硝酸盐还原的最重要驱动因素,它同时增加了反硝化和 DNRA,并在两个沼泽中促进 DNRA 而不是反硝化。在各种处理中,天然沼泽中的真菌和细菌生物量较高,但在人工沼泽中,难分解有机物增加了真菌生物量,这表明有机物限制了真菌的生长。我们发现,30 年后,人工沼泽的反硝化能力和 DNRA 与天然沼泽相似,而添加易腐有机物可促进天然沼泽和人工沼泽的氮保留。在不添加碳的对照处理下(下图),人工沼泽和天然沼泽的 DNRA 和反硝化率相似。天然沼泽的真菌和细菌生物量较高,而在人工建造的沼泽中则检测不到真菌生物量。在添加易腐 OM 的情况下(左上图),两个沼泽的 DNRA 和反硝化速率都会增加,DNRA 比反硝化更有利。添加难降解有机物(右上图)会增加反硝化作用,但不会影响 DNRA 或反硝化率。添加难降解 OM 还会增加构建沼泽中真菌生物量的可探测性。
Labile organic matter promotes nitrogen retention in natural and constructed gulf coast marshes
Coastal marshes mitigate allochthonous nitrogen (N) inputs to adjacent marine habitat; however, their extent is declining rapidly. As a result, marsh restoration and construction have become a major foci of wetland management. Constructed marshes can quickly reach similar plant biomass to natural marshes, but biogeochemical functions like N removal and retention can take decades to reach functional equivalency, often due to lags in organic matter (OM) pools development in newly constructed marshes. We compared denitrification and dissimilatory nitrate reduction to ammonium (DNRA) rates in a 32 year-old constructed marsh and adjacent reference marsh in the Northern Gulf of Mexico. Marsh sediments packed into 3 mm “thin discs” were subjected to three OM quality treatments (no OM addition, labile OM, or recalcitrant OM) and two N treatments (ambient nitrate or elevated nitrate) during a 13 day incubation. We found that OM addition, rather than marsh type or nitrate treatment, was the most important driver of nitrate reduction, increasing both denitrification and DNRA and promoting DNRA over denitrification in both marshes. Fungal and bacterial biomass were higher in the natural marsh across treatments, but recalcitrant OM increased fungal biomass in the constructed marsh, suggesting OM-limitation of fungal growth. We found that constructed marshes are capable of similar denitrification and DNRA as natural marshes after 30 years, and that labile OM addition promotes N retention in both natural and constructed marshes.
Graphical Abstract
Conceptual figure highlighting the findings of this experiment. Under control treatment with no C addition (bottom panel), constructed and natural marshes have similar rates of both DNRA and denitrification. The natural marsh has higher fungal and bacterial biomass, while fungal biomass is not detectable in the constructed marsh. Under labile OM additions (upper left panel), rates of both DNRA and denitrification are increased and DNRA becomes favored over denitrification in both marshes. Recalcitrant OM additions (upper right) increase denitrification, but do not affect DNRA or % denitrification. The addition of recalcitrant OM also increases the detectability of fungal biomass in the constructed marsh.
期刊介绍:
Biogeochemistry publishes original and synthetic papers dealing with biotic controls on the chemistry of the environment, or with the geochemical control of the structure and function of ecosystems. Cycles are considered, either of individual elements or of specific classes of natural or anthropogenic compounds in ecosystems. Particular emphasis is given to coupled interactions of element cycles. The journal spans from the molecular to global scales to elucidate the mechanisms driving patterns in biogeochemical cycles through space and time. Studies on both natural and artificial ecosystems are published when they contribute to a general understanding of biogeochemistry.