东海沉积物中氮循环的关键过程
发布时间：2023-03-28 18:38
氮元素作为海洋环境中的重要生源要素之一，通常被认为是初级生产力的限制因子，加之全球氮循环与碳循环在气候变化中的密切耦合以及人类活动对于氮元素排放的逐渐增加，海洋氮循环也就成为整个海洋生物地球化学循环中最为关键的一环。海洋中化合态氮的收支取决于游离态氮气的固定和化合态氮的丢失(N-loss)，前者主要由固氮生物执行，而后者主要由反硝化细菌和厌氧铵氧化细菌所实现。由于海洋氮循环受到多种过程的控制以及在量化各种过程速率方面存在很大的不确定性，全球氮的收支是否处于平衡仍然存在很大的争议。海洋沉积物是化合态氮丢失的一个重要场所，约5070%的化合态氮在此被移除，而其中50%以上的氮丢失又发生在陆架海沉积物中(Bohlen et al.2012; Gruber2008)，尽管该区域只占全球海洋面积的7.5%(Menard&Smith1966)。由此可见陆架海沉积物在全球海洋氮循环中所起的关键性作用。 反硝化、厌氧铵氧化和异化硝酸盐还原为铵(DNRA)是沉积物厌氧环境中氮循环的三种关键过程。前两个过程控制着沉积物中化合态氮的丢失，而DNRA则将NO3
【文章页数】：171 页
【学位级别】：博士
【文章目录】：
摘要 Abstract 1 Introduction
1.1 Nitrogen cycle in marine environment
1.1.1 Nitrogen composition
1.1.2 Nitrogen budget in marine environments
1.1.3 Marine nitrogen transformation processes
1.1.4 Methods in determining nitrogen transformations
1.2 N-loss in continental shelf sediments
1.3 Introduction to the East China Sea
1.3.1 General description
1.3.2 Nitrogen budget in the East China Sea
1.4 Aims of this thesis 2 Application of the isotope pairing technique in sediments where anammox, denitrification and DNRA coexist
Abstract
2.1 Introduction
2.2 Materials and procedures
2.2.1 Assumptions
2.2.2 Revised equations for calculations of anammox and denitrification rates after DNRA intrusion
2.2.3 Quantification effects of DNRA on anammox, denitrification and total benthic N2production
2.2.4 Revised procedure for estimating actual anammox, denitrification and DNRA rates in slurry incubation
2.3 Assessment
2.4 Discussion
2.5 Comments and recommendations 3 Anaerobic ammonium oxidation, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment
Abstract
3.1 Introduction
3.2 Materials and methods
3.2.1 Sample collection and preparation
3.2.2 15N slurry incubations
3.2.3 Chemical analysis
3.2.4 Rate calculations
3.3 Results
3.3.1 Water column and sediment characteristics
3.3.2 15N slurry incubations
3.3.3 Nitrate storage and release in the sediment
3.3.4 N-loss and nitrate reduction in slurry incubation
3.4 Discussion
3.4.1 The influence of nitrate release and DNRA on anammox and denitrification rates calculation with isotope pairing method
3.4.2 Distribution and regulation of anammox, denitrification and DNRA in ECS sediments
3.4.3 Biogeochemical significance of anammox, denitrification and DNRA in the ECS sediments
3.5 Conclusions 4 Direct measurements of benthic N-loss and DNRA in the East China Sea
Abstract
4.1 Introduction
4.2 Methods
4.2.1 Sample collection and preparation
4.2.2 General sediment characteristics
4.2.3 Net fluxes of O2and dissolved inorganic nitrogen
4.2.4 Core incubation for benthic N-loss
4.2.5 Slurry incubation for tracking anammox, denitrification and DNRA
4.2.6 Chemical analysis
4.3 Results
4.3.1 General characteristics of the investigation sites
4.3.2 Pore water nitrogen species profiles
4.3.3 Oxygen and nutrients net fluxes
4.3.4 Slurry incubation
4.3.5 Concentration series test for core incubation
4.3.6 N-loss from core incubation
4.3.7 DNRA from core incubation
4.4 Discussion
4.4.1 Isotope pairing technique testing with15NO3
- concentration and time series when anammox and denitrification co-exist
4.4.2 Underestimation of N-loss by15NO3
- diffusion limitation
4.4.3 Other evidence for supporting underestimation of benthic N-loss by IPT
4.4.4 A revised procedure for estimating benthic N-loss
4.4.5 DNRA and its effect on benthic nitrogen cycle
4.4.6 Global significance of the additional N-loss 5 Response of benthic nitrogen cycle to hypoxia of the Changjiang estuary
Abstract
5.1 Introduction
5.2 Materials and Methods
5.2.1 Sites description
5.2.2 Sediment and water sampling
5.2.3 Sediment characteristics
5.2.4 Sediment oxygen profiles
5.2.5 Track anammox, denitrification and DNRA with slurry incubations
5.2.6 Measuring oxygen uptake and nutrient fluxes with intact core incubations
5.2.7 Measuring anammox, denitrification and DNRA with intact core incubation
5.2.8 Rates calculations
5.3 Results
5.3.1 General characteristics
5.3.2 Pore water profiles of oxygen and nitrate
5.3.3 Sediment oxygen uptake (SOU)
5.3.4 Partitioning of anammox, denitrification and DNRA
5.3.5 Benthic N-loss and DNRA from core incubation
5.3.6 Nutrients net fluxes, nitrification and mineralization
5.3.7 Correlation of measured benthic nitrogen transformation rates with bottom water oxygen
5.4 Discussion
5.4.1 Response of SOU to reduced oxygen
5.4.2 Response of nutrient fluxes to reduced oxygen
5.4.3 Response of anammox, denitrification and DNRA to reduced oxygen
5.4.4 Integrated response of benthic nitrogen cycle to reduced oxygen
5.4.5 The fate of organic nitrogen 6 Conclusions and Prospect Reference Acknowledgements Supplementary Material 1 for Chapter 3 Supplementary Material 2 for Chapter 3 个人简历 发表的学术论文
本文编号：3773063
【文章页数】：171 页
【学位级别】：博士
【文章目录】：
摘要 Abstract 1 Introduction
1.1 Nitrogen cycle in marine environment
1.1.1 Nitrogen composition
1.1.2 Nitrogen budget in marine environments
1.1.3 Marine nitrogen transformation processes
1.1.4 Methods in determining nitrogen transformations
1.2 N-loss in continental shelf sediments
1.3 Introduction to the East China Sea
1.3.1 General description
1.3.2 Nitrogen budget in the East China Sea
1.4 Aims of this thesis 2 Application of the isotope pairing technique in sediments where anammox, denitrification and DNRA coexist
Abstract
2.1 Introduction
2.2 Materials and procedures
2.2.1 Assumptions
2.2.2 Revised equations for calculations of anammox and denitrification rates after DNRA intrusion
2.2.3 Quantification effects of DNRA on anammox, denitrification and total benthic N2production
2.2.4 Revised procedure for estimating actual anammox, denitrification and DNRA rates in slurry incubation
2.3 Assessment
2.4 Discussion
2.5 Comments and recommendations 3 Anaerobic ammonium oxidation, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment
Abstract
3.1 Introduction
3.2 Materials and methods
3.2.1 Sample collection and preparation
3.2.2 15N slurry incubations
3.2.3 Chemical analysis
3.2.4 Rate calculations
3.3 Results
3.3.1 Water column and sediment characteristics
3.3.2 15N slurry incubations
3.3.3 Nitrate storage and release in the sediment
3.3.4 N-loss and nitrate reduction in slurry incubation
3.4 Discussion
3.4.1 The influence of nitrate release and DNRA on anammox and denitrification rates calculation with isotope pairing method
3.4.2 Distribution and regulation of anammox, denitrification and DNRA in ECS sediments
3.4.3 Biogeochemical significance of anammox, denitrification and DNRA in the ECS sediments
3.5 Conclusions 4 Direct measurements of benthic N-loss and DNRA in the East China Sea
Abstract
4.1 Introduction
4.2 Methods
4.2.1 Sample collection and preparation
4.2.2 General sediment characteristics
4.2.3 Net fluxes of O2and dissolved inorganic nitrogen
4.2.4 Core incubation for benthic N-loss
4.2.5 Slurry incubation for tracking anammox, denitrification and DNRA
4.2.6 Chemical analysis
4.3 Results
4.3.1 General characteristics of the investigation sites
4.3.2 Pore water nitrogen species profiles
4.3.3 Oxygen and nutrients net fluxes
4.3.4 Slurry incubation
4.3.5 Concentration series test for core incubation
4.3.6 N-loss from core incubation
4.3.7 DNRA from core incubation
4.4 Discussion
4.4.1 Isotope pairing technique testing with15NO3
- concentration and time series when anammox and denitrification co-exist
4.4.2 Underestimation of N-loss by15NO3
- diffusion limitation
4.4.3 Other evidence for supporting underestimation of benthic N-loss by IPT
4.4.4 A revised procedure for estimating benthic N-loss
4.4.5 DNRA and its effect on benthic nitrogen cycle
4.4.6 Global significance of the additional N-loss 5 Response of benthic nitrogen cycle to hypoxia of the Changjiang estuary
Abstract
5.1 Introduction
5.2 Materials and Methods
5.2.1 Sites description
5.2.2 Sediment and water sampling
5.2.3 Sediment characteristics
5.2.4 Sediment oxygen profiles
5.2.5 Track anammox, denitrification and DNRA with slurry incubations
5.2.6 Measuring oxygen uptake and nutrient fluxes with intact core incubations
5.2.7 Measuring anammox, denitrification and DNRA with intact core incubation
5.2.8 Rates calculations
5.3 Results
5.3.1 General characteristics
5.3.2 Pore water profiles of oxygen and nitrate
5.3.3 Sediment oxygen uptake (SOU)
5.3.4 Partitioning of anammox, denitrification and DNRA
5.3.5 Benthic N-loss and DNRA from core incubation
5.3.6 Nutrients net fluxes, nitrification and mineralization
5.3.7 Correlation of measured benthic nitrogen transformation rates with bottom water oxygen
5.4 Discussion
5.4.1 Response of SOU to reduced oxygen
5.4.2 Response of nutrient fluxes to reduced oxygen
5.4.3 Response of anammox, denitrification and DNRA to reduced oxygen
5.4.4 Integrated response of benthic nitrogen cycle to reduced oxygen
5.4.5 The fate of organic nitrogen 6 Conclusions and Prospect Reference Acknowledgements Supplementary Material 1 for Chapter 3 Supplementary Material 2 for Chapter 3 个人简历 发表的学术论文
本文编号：3773063
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