title: Surface oscillation in peatlands: How variable and important is it?

authors: Fritz, Christian

subjects: hydrology

abstract: Hydrology, particularly the water table position below the surface, is an important control on biogeochemical and ecological processes in peatlands. The position of the water table is a function of total storage changes, drainable porosity and peatland surface oscillation (PSO). Because the absolute level of the peat surface (ASL) oscillates in a peatland, we can assign two different water table positions: the water table depth below the surface (relative water level, RWL) and the water table position above an absolute elevation datum eg. sea level (absolute water level, AWL). 

A review of 37 studies that report peatland surface oscillation indicate a wide range (0.4-55 cm), which is to the same order as (or one order smaller than) water storage changes and RWL fluctuations. PSO can vary substantially across a single peatland and through time. A set of mechanisms (flotation, compression/shrinkage, gas volume changes and freezing) is hypothesised to cause ASL changes. The potential of PSO to reduce RWL fluctuations trended (mean in %) floating peatlands (63) > bogs (21), fens (18) > disturbed peatlands (10) with respect to peatland types. 

To investigate the spatiotemporal variability of peatland surface oscillation, AWL and ASL were monitored continuously over a one-year period (one site) and monthly (23 sites) in a warm-temperate peatland that is dominated by Empodisma minus (Restionaceae). A new measurement method was developed by pairing two water level transducers, one attached to a stable benchmark (ÆAWL) and one attached to the peat surface (ÆRWL). 

From August 2005 until August 2006 the ASL oscillated at one site through a range of 22 cm following AWL fluctuations (in total 47 cm). Consequently, RWL fluctuations were reduced on average to 53% of AWL fluctuations. The strong AWL-ASL relationship was linear for 15 sites with manual measurements. However, eight sites showed significantly higher rates of peatland surface oscillation during the wet season (ie. high AWLs) and thus a non-linear behaviour. Temporary flotation of upper peat layers during the wet season may have caused this non-linear behaviour. On the peatland scale AWL fluctuations (mean 40 cm among sites) were reduced by 30–50% by PSO except for three sites with shallow and dense peat at the peatland margin (7–11%). The reduction of RWL fluctuation was high compared to literature values. The spatial variability of PSO seemed to match well with vegetation patterns rather than peat thickness or bulk density. Sites with large PSO showed high cover of Empodisma minus. 

Surface level changes exhibited surprisingly hysteretic behaviour subsequent to raised AWLs, when the rise of ASL was delayed. This delay reversed the positive ASL-AWL relationship because the surface slowly rose even though AWL started receding. Hysteresis was more pronounced during the dry season than during the wet season. The observed hysteresis can be sufficiently simulated by a simplistic model incorporating delayed ASL fluctuations. 

PSO has wide implications for peatland hydrology by reducing RWL fluctuations, which feed back to peat decomposition and plant cover and potentially to (drainable) porosity. Stable RWL also reduce the probability of surface run-off. It is further argued that the gas content of the roots of plants, particularly Empodisma minus, added enough buoyancy to detach the uppermost peat layers resulting in flotation.

text: Surface oscillation in peatlands: How variable and important is it? Hydrology, particularly the water table position below the surface, is an important control on biogeochemical and ecological processes in peatlands. The position of the water table is a function of total storage changes, drainable porosity and peatland surface oscillation (PSO). Because the absolute level of the peat surface (ASL) oscillates in a peatland, we can assign two different water table positions: the water table depth below the surface (relative water level, RWL) and the water table position above an absolute elevation datum eg. sea level (absolute water level, AWL). 

A review of 37 studies that report peatland surface oscillation indicate a wide range (0.4-55 cm), which is to the same order as (or one order smaller than) water storage changes and RWL fluctuations. PSO can vary substantially across a single peatland and through time. A set of mechanisms (flotation, compression/shrinkage, gas volume changes and freezing) is hypothesised to cause ASL changes. The potential of PSO to reduce RWL fluctuations trended (mean in %) floating peatlands (63) > bogs (21), fens (18) > disturbed peatlands (10) with respect to peatland types. 

To investigate the spatiotemporal variability of peatland surface oscillation, AWL and ASL were monitored continuously over a one-year period (one site) and monthly (23 sites) in a warm-temperate peatland that is dominated by Empodisma minus (Restionaceae). A new measurement method was developed by pairing two water level transducers, one attached to a stable benchmark (ÆAWL) and one attached to the peat surface (ÆRWL). 

From August 2005 until August 2006 the ASL oscillated at one site through a range of 22 cm following AWL fluctuations (in total 47 cm). Consequently, RWL fluctuations were reduced on average to 53% of AWL fluctuations. The strong AWL-ASL relationship was linear for 15 sites with manual measurements. However, eight sites showed significantly higher rates of peatland surface oscillation during the wet season (ie. high AWLs) and thus a non-linear behaviour. Temporary flotation of upper peat layers during the wet season may have caused this non-linear behaviour. On the peatland scale AWL fluctuations (mean 40 cm among sites) were reduced by 30–50% by PSO except for three sites with shallow and dense peat at the peatland margin (7–11%). The reduction of RWL fluctuation was high compared to literature values. The spatial variability of PSO seemed to match well with vegetation patterns rather than peat thickness or bulk density. Sites with large PSO showed high cover of Empodisma minus. 

Surface level changes exhibited surprisingly hysteretic behaviour subsequent to raised AWLs, when the rise of ASL was delayed. This delay reversed the positive ASL-AWL relationship because the surface slowly rose even though AWL started receding. Hysteresis was more pronounced during the dry season than during the wet season. The observed hysteresis can be sufficiently simulated by a simplistic model incorporating delayed ASL fluctuations. 

PSO has wide implications for peatland hydrology by reducing RWL fluctuations, which feed back to peat decomposition and plant cover and potentially to (drainable) porosity. Stable RWL also reduce the probability of surface run-off. It is further argued that the gas content of the roots of plants, particularly Empodisma minus, added enough buoyancy to detach the uppermost peat layers resulting in flotation.

year: 2006

title: Essays on Fintech development

authors: Tang, Mengxuan

abstract: Fintech is a contraction of the term "financial technology", which has become increasingly popular in the financial sector in recent years. Even the outbreak of the COVID-19 pandemic in December 2019 has not changed the fact that the Fintech industry is growing. The rapid development of Fintech has significantly impacted the traditional financial landscape, redefining the delivery of financial services, broadening their coverage, and significantly improving efficiency and convenience, injecting new vitality into the global financial industry.

The aim of this thesis is to explore the impact of Fintech on the incumbent financial system and the real economy in the Chinese context. First, to gauge the development of the Fintech area in China, this paper uses various Fintech development indicators. Notably, this thesis builds the Fintech development index by combining the multidimensional information that involves advanced technologies and Fintech-related fields. The study also uses the Peking University Digital Financial Inclusion Index of China (PKU-DFIIC) and hand-collected and constructed datasets of Fintech patents. Second, this thesis comprehensively analyses the implications of Fintech developments on corporate operational strategies in several key areas including risk-taking, liquidity creation, diversification, fraud, tax avoidance, financing, and investment policies. By exploring how Fintech shapes corporate development strategies and influences value growth in these areas, the thesis reveals the role of Fintech in optimizing resource allocation, improving corporate efficiency, and reducing operational risk. Moreover, the study analyses the potential risks and challenges that the Fintech development may pose.

The main contribution of this thesis is to provide new empirical evidence for the impact of Fintech on the development of traditional financial institutions and the real economy and to fill the gaps in existing research. Through an in-depth exploration of the economic consequences of the Fintech field, this paper not only reveals the role of Fintech in promoting the transformation of the real economy but also provides new perspectives on the benign development of the Fintech industry. Meanwhile, the findings provide valuable insights into the transformation of China's existing economic system, especially in terms of how to optimize the financial service system, improve the efficiency of resource allocation, and achieve sustainable growth in the context of the digital economy, which has important political implications.

text: Essays on Fintech development Fintech is a contraction of the term "financial technology", which has become increasingly popular in the financial sector in recent years. Even the outbreak of the COVID-19 pandemic in December 2019 has not changed the fact that the Fintech industry is growing. The rapid development of Fintech has significantly impacted the traditional financial landscape, redefining the delivery of financial services, broadening their coverage, and significantly improving efficiency and convenience, injecting new vitality into the global financial industry.

The aim of this thesis is to explore the impact of Fintech on the incumbent financial system and the real economy in the Chinese context. First, to gauge the development of the Fintech area in China, this paper uses various Fintech development indicators. Notably, this thesis builds the Fintech development index by combining the multidimensional information that involves advanced technologies and Fintech-related fields. The study also uses the Peking University Digital Financial Inclusion Index of China (PKU-DFIIC) and hand-collected and constructed datasets of Fintech patents. Second, this thesis comprehensively analyses the implications of Fintech developments on corporate operational strategies in several key areas including risk-taking, liquidity creation, diversification, fraud, tax avoidance, financing, and investment policies. By exploring how Fintech shapes corporate development strategies and influences value growth in these areas, the thesis reveals the role of Fintech in optimizing resource allocation, improving corporate efficiency, and reducing operational risk. Moreover, the study analyses the potential risks and challenges that the Fintech development may pose.

The main contribution of this thesis is to provide new empirical evidence for the impact of Fintech on the development of traditional financial institutions and the real economy and to fill the gaps in existing research. Through an in-depth exploration of the economic consequences of the Fintech field, this paper not only reveals the role of Fintech in promoting the transformation of the real economy but also provides new perspectives on the benign development of the Fintech industry. Meanwhile, the findings provide valuable insights into the transformation of China's existing economic system, especially in terms of how to optimize the financial service system, improve the efficiency of resource allocation, and achieve sustainable growth in the context of the digital economy, which has important political implications.

year: 2025-08-01

title: Review: Memoirs of Active Service

authors: Cheesman, Sue

subjects: Maaka Pepene

abstract: Ka maumahara tonu tatou ki a ratou - we will remember them…poignant last words…   bidding farewell to a generation of veterans moving on...leaving fragments  of memories and diaries for children/grandchildren to honour, celebrate and remember …black costumes billow, fold, swirl and wrap the dancers bodies…wide sweeping arm movements…jumps and turns…slides on all fours - provides the vehicle for five accomplished dancers to fill the space with fluidity and lyricism in this very moving finale, a lament set to Albinoni’s adagio - maybe old soldiers never die.

text: Review: Memoirs of Active Service Ka maumahara tonu tatou ki a ratou - we will remember them…poignant last words…   bidding farewell to a generation of veterans moving on...leaving fragments  of memories and diaries for children/grandchildren to honour, celebrate and remember …black costumes billow, fold, swirl and wrap the dancers bodies…wide sweeping arm movements…jumps and turns…slides on all fours - provides the vehicle for five accomplished dancers to fill the space with fluidity and lyricism in this very moving finale, a lament set to Albinoni’s adagio - maybe old soldiers never die.

year: 2007