title: Buried Alive or Washed Away The Challenging Life of Mangroves in the Mekong Delta

authors: Fagherazzi, Sergio

subjects: Science & Technology

abstract: Mangroves colonize tropical shorelines, protecting coastal communities and providing valuable ecosystem services. Mangroves associated with deltas cope with a very dynamic environment characterized by strong gradients in salinity, deposition triggered by sediment inputs, and erosion caused by waves and currents. Mangroves are adapted to this ever-changing landscape, with different species colonizing different elevations in response to inundation frequency. A series of feedbacks between hydrodynamics, sediment transport, and mangroves was observed in a fringe forest of the Mekong Delta, Vietnam. Sonneratia spp. rapidly encroach upon sandy areas because the stable substrate favors seedling establishment. In contrast, fewer seedlings are present in muddy locations where currents and waves frequently rework the bottom. Along muddy shorelines that are eroding, turbulence increases local scour near roots and trunks, undercutting the trees. Enhanced sediment accumulation due to delta progradation can smother the mangrove roots and lead to forest dieback. We find clear evidence that mangroves affect both hydrodynamics and sediment transport, thus engineering the landscape and enhancing sediment trapping and delta progradation. Sonneratia spp. are replaced by Aegiceras corniculatum, Avicennia marina, and Nypa fruticans when the seabed becomes high enough, indicating that ecological succession is present in a fast prograding deltaic environment. Thus, it is imperative to determine the small-scale feedbacks between mangroves, hydrodynamics, and sediment transport in order to build quantitative ecogeomorphic models of deltaic sedimentation that can be used to explain the distribution of mangrove species, the forest structure, and large-scale dynamics in a tropical deltaic setting.

text: Buried Alive or Washed Away The Challenging Life of Mangroves in the Mekong Delta Mangroves colonize tropical shorelines, protecting coastal communities and providing valuable ecosystem services. Mangroves associated with deltas cope with a very dynamic environment characterized by strong gradients in salinity, deposition triggered by sediment inputs, and erosion caused by waves and currents. Mangroves are adapted to this ever-changing landscape, with different species colonizing different elevations in response to inundation frequency. A series of feedbacks between hydrodynamics, sediment transport, and mangroves was observed in a fringe forest of the Mekong Delta, Vietnam. Sonneratia spp. rapidly encroach upon sandy areas because the stable substrate favors seedling establishment. In contrast, fewer seedlings are present in muddy locations where currents and waves frequently rework the bottom. Along muddy shorelines that are eroding, turbulence increases local scour near roots and trunks, undercutting the trees. Enhanced sediment accumulation due to delta progradation can smother the mangrove roots and lead to forest dieback. We find clear evidence that mangroves affect both hydrodynamics and sediment transport, thus engineering the landscape and enhancing sediment trapping and delta progradation. Sonneratia spp. are replaced by Aegiceras corniculatum, Avicennia marina, and Nypa fruticans when the seabed becomes high enough, indicating that ecological succession is present in a fast prograding deltaic environment. Thus, it is imperative to determine the small-scale feedbacks between mangroves, hydrodynamics, and sediment transport in order to build quantitative ecogeomorphic models of deltaic sedimentation that can be used to explain the distribution of mangrove species, the forest structure, and large-scale dynamics in a tropical deltaic setting.

year: 2017

title: Closing in on the oxygen isotopic fractionation factor between calcite and water using natural carbonates

authors: Breitenbach, Sebastian F.M.

abstract: The oxygen isotopic fractionation between water and calcite is the cornerstone for estimating the formation temperature of calcite [1, 2, 3]. The oxygen isotope thermometer is one of the most valuable tools in geothermometry, palaeoclimatology and palaeoceanography

text: Closing in on the oxygen isotopic fractionation factor between calcite and water using natural carbonates The oxygen isotopic fractionation between water and calcite is the cornerstone for estimating the formation temperature of calcite [1, 2, 3]. The oxygen isotope thermometer is one of the most valuable tools in geothermometry, palaeoclimatology and palaeoceanography

year: 2019

title: He reo amiorangi

authors: Roa, Tom

subjects: Māori language

abstract: This paper discusses a project involving the translation of a learning management system (LMS), Modular Object-Oriented Dynamic Learning Environment (Moodle), into te reo Māori so that users of this LMS, learners, teachers and administrators who have a high level of competence in the language, can work within a fully Māori environment. Aspects of the project referred to here include adaptation of the style guide created by Te Taura Whiri for the Microsoft project, use of the Microsoft translation guidelines, the philosophy guiding the translation and the translation process itself (with examples). The process by which the project was evaluated is also discussed.

text: He reo amiorangi This paper discusses a project involving the translation of a learning management system (LMS), Modular Object-Oriented Dynamic Learning Environment (Moodle), into te reo Māori so that users of this LMS, learners, teachers and administrators who have a high level of competence in the language, can work within a fully Māori environment. Aspects of the project referred to here include adaptation of the style guide created by Te Taura Whiri for the Microsoft project, use of the Microsoft translation guidelines, the philosophy guiding the translation and the translation process itself (with examples). The process by which the project was evaluated is also discussed.

year: 2006