Modelling the effect of marine processes on deltaic wetlands

Deltaic wetlands are among the most biodiverse systems on earth, provide important ecosystem services, and are natural buffers against violent storms and hurricanes. Marine processes change the planar configuration and internal stratigraphy of deltaic wetlands, and understanding their contribution to wetlands development and deterioration processes is a key issue for society. In this thesis, field data and numerical models are used to investigate the effect of marine processes on the formation and evolution of deltaic wetlands. The first part of this work focuses on the effect of micro and meso tides on the hydrodynamics, morphodynamics, and stratigraphy of deltaic distributaries. Data from instruments deployed in Apalachicola Bay (FL) were used to investigate the hydrodynamics of river mouths. Investigating the hydrodynamics is the first step for a deeper understanding of sediment transport processes, and possible implications for the morphological evolution of these depositional environments. The effect of micro and meso tides on the morphology and stratigraphy of mouth bars is then explored by using numerical and analytical tools. Mouth bars are the building units of river deltas and continuous bifurcations around them allow delta progradation and the formation of new deltaic islands. The second part of this work focuses on the effect of wind waves on salt marsh deterioration using cellular automata and process-based models. Special attention is given to salt marsh resilience to extreme events, to the effect of variable erosional resistance on the large scale morphodynamic response of salt marshes to wind waves, and to the identification of geomorphic features indicative of wetlands deterioration. Results from cellular automata and process-based models are compared to field and literature data

Rethinking Meaning: An Ecological Perspective on Language

Abstract In a view of language as part of embodied and situated cognition, reduction of its meaning to individual mental representations ceases to be sufficient. Language relies on and at the same time enables distributed cognition thus the key aspects of meaning are in the interaction of individuals within their world. This special issue is an outcome of a workshop, which gathered representatives of several disciplines in a common effort to find appropriate theoretical concepts for the characterization of those aspects of meaning that lie in the mutual constraining between language and collective practice. The emerging picture is complex, involving multimodal participatory construction of meaning in multiple systems and on multiple timescales. The Authors, however propose also several innovative methods to navigate this complexity. In this short introduction we aim at placing the works contained in this issue on a broader map of ongoing efforts to understand language as a proper part of human ecology

Salt marsh erosion rates and boundary features in a shallow Bay

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Earth Surface 121 (2016): 1861–1875, doi:10.1002/2016JF003975.Herein, we investigate the relationship between wind waves, salt marsh erosion rates, and the planar shape of marsh boundaries by using aerial images and the numerical model Coupled-Ocean-Atmosphere-Wave-Sediment-Transport Modeling System (COAWST). Using Barnegat Bay, New Jersey, as a test site, we found that salt marsh erosion rates maintain a similar trend in time. We also found a significant relationship between salt marsh erosion rates and the shape of marsh boundaries which could be used as a geomorphic indicator of the degradation level of the marsh. Slowly eroding salt marshes are irregularly shaped with fractal dimension higher than rapidly deteriorating marshes. Moreover, for low-wave energy conditions, there is a high probability of isolated and significantly larger than average failures of marsh portions causing a long-tailed distribution of localized erosion rates. Finally, we confirm the existence of a significant relationship between salt marsh erosion rate and wind waves exposure. Results suggest that variations in time in the morphology of salt marsh boundaries could be used to infer changes in frequency and magnitude of external agents.Department of the Interior Hurricane Sandy Recovery program Grant Number: GS2-2D; NSF DEB Grant Number: 0621014; OCE Grant Number: 12382122017-04-2

Sensitivity of flood hazard and damage to modelling approaches

Combination of uncertainties in water level and wave height predictions for extreme storms can result in unacceptable levels of error, rendering flood hazard assessment frameworks less useful. A 2D inundation model, LISFLOOD-FP, was used to quantify sensitivity of flooding to uncertainty in coastal hazard conditions and method used to force the coastal boundary of the model. It is shown that flood inundation is more sensitive to small changes in coastal hazard conditions due to the setup of the regional model, than the approach used to apply these conditions as boundary forcing. Once the threshold for flooding is exceeded, a few centimetres increase in combined water level and wave height increases both the inundation and consequent damage costs. Improved quantification of uncertainty in inundation assessments can aid long-term coastal flood hazard mitigation and adaptation strategies, to increase confidence in knowledge of how coastlines will respond to future changes in sea-level

Modelling the Transport and Export of Sediments in Macrotidal Estuaries with Eroding Salt Marsh (vol 41, pg 1551, 2018)

© 2018 Coastal and Estuarine Research Federation Abstract In the original article, Xiaorong Li’s given and family names were transposed. It is correct as shown here. The original article has been corrected

Quantification of the uncertainty in coastal storm hazard predictions due to wave‐current interaction and wind forcing

Coastal flood warning and design of coastal protection schemes rely on accurate estimations of water level and waves during hurricanes and violent storms. These estimations frequently use numerical models, which, for computational reasons, neglect the interaction between the hydrodynamic and wave fields. Here, we show that neglecting such interactions, or local effects of atmospheric forcing, causes large uncertainties, which could have financial and operational consequences because flood warnings are potentially missed or protection schemes underdesigned. Using the Severn Estuary, SW England, we show that exclusion of locally generated winds underestimates high water significant wave height by up to 90.1%, high water level by 1.5%, and hazard proxy (water level + 1/2 significant wave height) by 9.1%. The uncertainty in water level and waves is quantified using a system to model tide‐surge‐wave conditions, Delft3D‐FLOW‐WAVE in a series of eight model simulations for four historic storm events