Morphological characterization of ponds and tidal courses in coastal wetlands using Google Earth imagery

Ponds and tidal courses are significant landforms that frequently arise in marshes and tidal flats environments. An understanding of their development and permanence is relevant to determine future dynamic processes that alter tidal flats and salt marshes environments, such as changes in the sea level, increase in the wave activity, and some other variations associated to the climate change. Direct access for monitoring in these regions is complex, extremely expensive and not always feasible. Remote sensing imagery represents a monitoring alternative, but requires the research of specific image processing procedures to extract the information concerning to these environmental studies. In this work, we developed a methodology for assessing the relevant morphological parameters of ponds and tidal courses using Google Earth imagery. An automatic classifier identifies these landforms as such (accuracy over 86%), producing a shape descriptors dataset. Then, ponds and tidal courses in tidal flats are morphologically characterized, and their behavior is compared to the surrounding environment. Subsequent analysis found significant differences in morphological characteristics that arise independently of the marsh environmental conditions. The evidence suggests that the evolution processes of the depressions in salt flat environments are clearly different in comparison with salt marshes environments. In salt marshes, the permanence and evolution of the depressions is related to the age of marshes, whereas in tidal flats the dynamic processes and sediment input have influence on depressions evolution.Fil: Revollo Sarmiento, Gisela Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; ArgentinaFil: Revollo Sarmiento, Natalia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Delrieux, Claudio Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; ArgentinaFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Geología; Argentin

Bio-physical controls on tidal network geomorphology

The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the authorLooking over a tidal wetland, the tidal network characterised by its intricate system of bifurcating, blind-ended tidal courses clearly stands out from the overall landscape. This tidal landform exerts a fundamental control on the morphology and ecology within the tidal environment. With today’s recognition of the ecological, economical and societal values provided by tidal wetlands, which has been notably reflected in the development of restoration management strategies across Europe and USA, there is a need to fully understand the nature and development of tidal networks as well as their relationships with associated landforms and biotic components (e.g. vegetation), to eventually guarantee the success of current and future restoration practices. Accordingly, this research aims to bring further insights into the bio-physical controls on the geomorphology of tidal networks. To this end, a combination of remote sensing, modelling and field activities was employed. A geo-spatial analysis was performed at Queen Mary, University of London (UK), to address the variability of tidal network patterns. A series of network scale morphometric variables was extracted using airborne LiDAR data among selected tidal networks across the UK depicting different planview morphologies, and supplemented with the collection of corresponding marsh scale environmental variables from published sources. Multivariate statistics were then performed to characterise the variability of tidal network patterns and identify the inherent environmental controls. The analysis has revealed that every network type can be characterised based upon measures of network size and complexity, with each network pattern depicting proper morphometric aspects. Particularly, the stream Strahler order and the median depth of the network main channel have the highest discriminating weight on the patterns investigated. High correlation between the latter variable and network main channel width has revealed that linear, linear-dendritic and dendritic networks followed a transitional gradient in their aspect ratio approximated by a power law and thus are seen to depict similar erosional processes. To the contrary, meandering networks clearly depart from this relationship, and show particular segregation in their aspect ratios with respect to dendritic networks. Globally, differentiation on network morphometric properties has been linked to environmental conditions specific to the marsh physiographic setting within which a tidal network develops. Conceptually, tidal networks seem to adapt to marsh environmental conditions by adopting suitable morphologies to drain their tidal basin effectively. An eco-geomorphic modelling framework was developed at University of Trento (Italy), to address tidal network morphological development. In line with current theories as well as modelling advances and challenges in the field of tidal network ontogeny, emphasis was thus placed on the investigation of tidal channel formation and evolution in progressive marsh accretional context. Under these environmental conditions, tidal network development can be ascribed to the combination of two channel-forming processes: channel initiation results from bottom incisions in regions where topographic depressions occur; channel elaboration results from differential deposition, contributing to the deepening of the tidal channels relative to the adjacent marsh platform. Further evolutionary stages including channel reduction proceed from the horizontal progradation of the marsh platform which may lead eventually to channel infilling. Moreover, both qualitative and quantitative results allude to an acceleration of the morphological development of the synthetic tidal networks with increasing sediment supply. These different observations thus emphasise the prevalence of depositional processes in shaping tidal channels. In a second stage, the investigation was extended to the role of the initial tidal flat morphology as an inherent control on tidal network development, by considering different scenarios of topographic perturbations, which has revealed its legacy on tidal network morphological features. Modelling experiments have also acknowledged salt marsh macrophytes as a potential control on network evolution depending on their biomass distribution within the tidal frame. However, tidal channel morphodynamcis appears to be sensitive to the way biomass growth is mathematically parameterised in the model. In view of the current challenges in transcribing mathematically such a dynamic process and the relevance of bio-physical interactions in driving salt marsh and tidal network evolution, a field survey was conducted in a temperate salt marsh in the Netherlands, as part of the mobility to UNESCO-IHE (Netherlands) in partnership with University of Antwerp (Belgium), to assess vegetation distribution and productivity in the tidal frame. Particularly, emphasis was placed on extending investigations on the possible presence of relationships involving vegetation properties in different climatic and ecological conditions from those characterising these previously documented relationships. Regression analysis has revealed that biomass growth can be expressed as a linear function of marsh relative elevation, providing therefore direct empirical validation for corresponding assumptions reported in the literature and used in the present modelling framework; surprisingly, that increase did not correlate with an increase in species richness and diversity. Analysis of likely associations between vegetation morphometrics and total standing biomass yielded only a single linear relationship linking the latter variable to stem height. In truth, these observations may bear reconsiderations on the global validity of the assumptions used in the formulation of some eco-geomorphic processes which are applied in the study and prediction of wetland resiliency facing climate change

Coastal impacts due to sea-level rise

Author Posting. © Annual Reviews, 2007. This is the author's version of the work. It is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Earth and Planetary Sciences 36 (2008): 601-647, doi:10.1146/annurev.earth.35.031306.140139.Recent estimates by Intergovermental Panel on Climate Change (2007) are that global sea level will rise from 0.18 to 0.59 m by the end of this century. Rising sea level not only inundates low-lying coastal regions, but it also contributes to the redistribution of sediment along sandy coasts. Over the long-term, sea-level rise (SLR) causes barrier islands to migrate landward while conserving mass through offshore and onshore sediment transport. Under these conditions, coastal systems adjust to SLR dynamically while maintaining a characteristic geometry that is unique to a particular coast. Coastal marshes are susceptible to accelerated SLR because their vertical accretion rates are limited and they may drown. As marshes convert to open water, tidal exchange through inlets increases, which leads to sand sequestration on tidal deltas and erosion of adjacent barrier shorelines

UAV photogrammetry in intertidal mudflats: accuracy, efficiency, and potential for integration with satellite imagery

The rapid, up-to-date, cost-effective acquisition and tracking of intertidal topography are the fundamental basis for timely, high-priority protection and restoration of the intertidal zone. The low cost, ease of use, and flexible UAV-based photogrammetry have revolutionized the monitoring of intertidal zones. However, the capability of the RTK-assisted UAV photogrammetry without ground control points, the impact of flight configuration difference, the presence of surface water in low-lying intertidal areas on the photogrammetric accuracy, and the potential of UAV/satellite Synergy remain unknown. In this paper, we used an RTK-assisted UAV to assess the impact of the above-mentioned considerations quantitatively on photogrammetric results in the context of annual monitoring of the Chongming Dongtan Nature Reserve, China based on an optimal flight combination. The results suggested that (1) RTK-assisted UAVs can obtain high-accuracy topographic data with a vertical RMSE of 3.1 cm, without the need for ground control points. (2) The effect of flight altitude on topographic accuracy was most significant and also nonlinear. (3) The elevation obtained by UAV photogrammetry was overestimated by approximately 2.4 cm in the low-lying water-bearing regions. (4) The integration of UAV and satellite observations can increase the accuracy of satellite-based waterline methods by 51%. These quantitative results not only provide scientific insights and guidelines for the balance between accuracy and efficiency in utilizing UAV-based intertidal monitoring, but also demonstrate the great potential of combined UAV and satellite observations in identifying coastal erosion hotspots. This establishes high-priority protection mechanisms and promotes coastal restoration

Three-Dimensionally Preserved Arthropods from the Cambrian (Furongian) of Quebec and Wisconsin: Systematics, Phylogeny, Ichnology, and Taphonomy

Three new types of arthropod from Cambrian intertidal lithofacies of the Elk Mound Group and Lodi Member of Wisconsin, and the Potsdam Group of Quebec are described. These arthropods are preserved ventrally in three dimensions – allowing detailed characterization of morphology. Arenocaris inflata, from the Furongian Elk Mound Group and St. Lawrence Formation, is the earliest occurrence of a phyllocarid. Mosineia macnaughtoni, a large (\u3e10 cm long) euthycarcinoid arthropod, also occurs in Elk Mound strata. Mictomerus melochevillensis represents a new family of early euthycarcinoids, and is a large (8–10+ cm long) arthropod with eleven pairs of homopodous, uniramous limbs. Phylogenetic analyses and reviews of Paleozoic phyllocarid systematics are presented, using morphology-based characters from Cambrian to Recent taxa. Resulting cladograms place Arenocaris inflata into a systematic context, and reveal that the families Ceratiocarididae and Caryocarididae, as traditionally defined, are paraphyletic. Caryocarididae is elevated to subordinal rank (Caryocaridina n. suborder), resulting in two monophyletic suborders. Emended diagnoses are integrated into this analysis, and result in synonymy of 30 Cambrian – Silurian caryocaridids and ceratiocaridids into 11 pre-existing species. The phyllocarid Arenocaris inflata from the Elk Mound Group of Wisconsin and the large enigmatic arthropod Mictomerus melochevillensis from The Potsdam Group of Quebec are both directly associated with trace fossils. Direct association between these arthropods and their traces allows functional morphological details of the animal to be assessed, provides a framework for understanding how arthropods can be sand-cast in three-dimensions, and helps provide insight about subaerially-produced traces from the Potsdam Group

Fusion of airborne LiDAR, multispectral imagery and spatial modelling for understanding saltmarsh response to sea-level rise

Coastal ecosystems are considered to be sensitive to changes in environmental forcing, particularly sea-level rise. Saltmarshes occupy a discrete lateral and vertical position that is fundamentally controlled by the position of sea level, but the nature of other factors such as broader scale shoreline dynamics and anthropogenic ensure that the nature and extent of sea-level rise impacts on saltmarshes are globally variable, and locally complex. Thus, there is a need to understand these controls and to predict the potential response of saltmarsh systems to sea-level change at the local scale. The present research presents a multifaceted methodology for investigating the response of saltmarshes due to sea-level rise at local scales with application to the Odiel saltmarshes (SW-Spain), using elevation data derived from Light detection and ranging (LiDAR), high spatial resolution multispectral imagery and spatial modelling, that in combination with historical estuary evolution and field observation can be applied for effective management and conservation of saltmarshes in the context of sea-level change. SLAMM (Sea Level Affecting Marshes Model) has been used to evaluate coastal wetland habitat response to sea-level rise Accurate model spatial model inputs such as digital elevation models (DEMs) and saltmarsh habitat map are essential to reduce uncertainties in the model outputs, and part of this thesis has been focused on improving accuracy in saltmarsh elevation and habitat maps. Additionally, a sensitivity and uncertainty analysis was undertaken to explore first the relative importance of data quality and resolution (spatial and vertical) in the elevation data and saltmarsh habitat classification layers, and then the global uncertainty of the model outputs using a Monte Carlo approach. Our findings suggested that model is sensitive to DEM and habitat map resolution, and that historical sea-level trend and saltmarsh accretion rates are the predominant factors that influence uncertainty in predictions of change in saltmarsh habitats

The value of the geological record in determining rates and drivers of coastal lagoon shoreline development.

This research investigated the feasibility of using the geological record to determine rates and drivers of morphological change in coastal lagoons. Substrate elevation in these environments is of primary importance for survival of wetland habitats, the effectiveness of drainage and flood mitigation functions delivered by those habitats, and the success of potential carbon sequestration programs. Investigating rates and trajectories of lagoon evolution will become more important given the effects of accelerating sea-level rise and human interventions, direct and indirect, on all coastal depositional environments. Elevation change on coastal lagoon shorelines is the net result of numerous sediment accretion and erosion cycles that are subject to considerable uncertainty. Numerous hydrological, biological, geological and anthropogenic processes interact over a range of timescales, and are subject to complex relationships and non-linear feedbacks. To successfully reproduce and predict long-term shoreline change with numerical models, the net effect of these processes must be captured and attributed to appropriate functions and parameter values. Shoreline processes are typically measured in-situ, and measurements would need to span several decades in order to reach an adequate level of confidence about the representativeness of the results. This is particularly true in regions subject to inter-decadal climate variability, such as the El Niño Southern Oscillation in southeast Australia. Even with a sufficiently long-term empirical dataset, the lasting effect of sediment accumulation for elevation change depends strongly on sub-surface processes (root production, decomposition, compaction and soil water content), which take place over still longer timescales and require sub-surface investigation. Reliance on the depositional history captured in the geological record would improve confidence in longer-term rates of morphological change. It would reduce the time and effort required from years (at least) of field measurements to a few months of laboratory work. The effectiveness of the geological record for model parameterisation and calibration, however, depends on the potential to infer drivers of elevation change as well as rates. For this research, soil samples up to 1.8 m depth were obtained in cross-shore core transects from prograded shorelines in three NSW coastal lagoons: Wooloweyah Lagoon near Yamba; Lake Innes near Port Macquarie; and Neranie Bay within Myall Lake. The three lagoons and the segments of shoreline sampled were selected to be as low-energy as possible by avoiding the effects of fluvial and tidal processes that could render intractable shoreline processes with already complex interactions. Each core sample was split and scanned for high-resolution optical images and down-core profiles of magnetic susceptibility, and geochemistry. These datasets enabled the identification and correlation of depositional units between cores and along cross-shore profiles, and thus high-level analysis of shorelines stratigraphy. From each site or transect at least one representative core was selected for detailed investigation, sub-sampled at 10 mm resolution and analysed for grain size, moisture content, density, organic content, and isotopic activity of 210Pb, 137Cs and 14C which provided the approximate timing of deposition for each sub-sample. Mass accumulation rates (g/cm2/yr) and vertical accretion rates (mm/yr) were calculated for correlation with physical sediment properties. At one site, Neranie Bay, this detailed level of analysis was performed for three cores, covering most of the cross-shore transect. Accretion rates calculated for approximately the last 100 years from 210Pb analysis averaged less than 2 mm/yr, consistent with figures reported for similar environments elsewhere in southeast Australia, and at the lower end of the spectrum for internationally reported rates. Preceding the timing of European settlement, accretion rates at the three sites were considerably lower. Recent rates of sediment mass accumulation mostly ranged from 0.02-0.2 g/cm2/yr, but this figure is rarely reported elsewhere and is therefore difficult to compare. Accretion and mass accumulation rates reduced rapidly down-core in the upper few centimetres of each sample, suggesting a significant role for organic matter decomposition for at least several decades following initial deposition. Changes in moisture content and bulk density were observed over similar depths. This research highlights the importance of analysing soil samples to sufficient depth and ensuring sub-surface processes have ceased to have significant impacts on down-core changes before making interpretations about trends over time. A controlling influence of organic content over vertical accretion (and therefore elevation change) was found for the three sites investigated. This control was independent of the inorganic sediment input, which was often higher (by mass) than the organic input. At Neranie Bay, cross-shore trends in organic content were evident. Organic matter input at the surface of the soil sample was greatest when the sample was taken from a higher elevation with less frequent inundation (i.e. short hydroperiod). The proportion of organic matter retained in the soil profile, however, was lowest where hydroperiod was shortest. On balance, organic matter makes the greatest contribution to elevation change when hydroperiod is longest. It could not be determined whether this was caused by higher rates of sub-surface decomposition with short hydroperiod, or high rates of below-ground productivity with long hydroperiod (or both). Either way the results are counter-intuitive and could not be determined without reliance on the geological record. The cross-shore trend that was established from this research is of vital importance. The relationship between hydroperiod and organically driven elevation change results in self-regulating, negative feedback and therefore greater resilience to increases in hydroperiod when the relationship is as reported here. When the reverse relationship is found, however, resilience to increased hydroperiod, and therefore sea level rise, would be compromised because inundation would continually decrease the ability of organic sedimentation to drive accretion, potentially resulting in habitat loss and exposing the shoreline to the risk of erosion. Previous studies suggest that this cross-shore relationship varies on a site-by-site basis. Determining the direction of the relationship with field measurements would take years and still be subject to much higher uncertainty than the methods employed here. This research has shown that the geological record is not only a feasible source of information about accretion rates and drivers, but also a preferable one. Provided further research can succeed in linking sub-surface retention of organic matter to contemporary primary production at the surface, the geological record will provide a more efficient and effective method of designing and calibrating much-needed predictive models to explore scenarios of shoreline development and wetland survival under changing conditions. Further research should also target a range of geologic and climatic settings to differentiate between drivers that can be generalised across all sites and those that vary on a site-by-site basis

Biodiversity beyond species census: assessing organisms' traits and functional attributes using computer vision

César Herrera studied the functions of intertidal crabs in estuarine mudflats in Townsville. He developed a novel workflow and software that use computer vision to monitor crab movement and behaviour. His analytical framework is more effective than traditional sampling techniques, and it will help ecologists to gather more and better ecological information on crabs

The Global Diversity of Parasitic Isopods Associated with Crustacean Hosts (Isopoda: Bopyroidea and Cryptoniscoidea)

Parasitic isopods of Bopyroidea and Cryptoniscoidea (commonly referred to as epicarideans) are unique in using crustaceans as both intermediate and definitive hosts. In total, 795 epicarideans are known, representing ∼7.7% of described isopods. The rate of description of parasitic species has not matched that of free-living isopods and this disparity will likely continue due to the more cryptic nature of these parasites. Distribution patterns of epicarideans are influenced by a combination of their definitive (both benthic and pelagic species) and intermediate (pelagic copepod) host distributions, although host specificity is poorly known for most species. Among epicarideans, nearly all species in Bopyroidea are ectoparasitic on decapod hosts. Bopyrids are the most diverse taxon (605 species), with their highest diversity in the North West Pacific (139 species), East Asian Sea (120 species), and Central Indian Ocean (44 species). The diversity patterns of Cryptoniscoidea (99 species, endoparasites of a diverse assemblage of crustacean hosts) are distinct from bopyrids, with the greatest diversity of cryptoniscoids in the North East Atlantic (18 species) followed by the Antarctic, Mediterranean, and Arctic regions (13, 12, and 8 species, respectively). Dajidae (54 species, ectoparasites of shrimp, mysids, and euphausids) exhibits highest diversity in the Antarctic (7 species) with 14 species in the Arctic and North East Atlantic regions combined. Entoniscidae (37 species, endoparasites within anomuran, brachyuran and shrimp hosts) show highest diversity in the North West Pacific (10 species) and North East Atlantic (8 species). Most epicarideans are known from relatively shallow waters, although some bopyrids are known from depths below 4000 m. Lack of parasitic groups in certain geographic areas is likely a sampling artifact and we predict that the Central Indian Ocean and East Asian Sea (in particular, the Indo-Malay-Philippines Archipelago) hold a wealth of undescribed species, reflecting our knowledge of host diversity patterns

Meiofauna Biodiversity and Ecology

Meiofauna are small organisms ranging 30–500 μm in body size, inhabiting marine sediments and other substrata all over the world, even the most extreme ones. We can find many different meiofaunal species in a very small handful of sediment, with the most varied and curious shapes, that share peculiar lifestyles, ecological relationships, and evolutionary traits. They contribute significantly to the processes and functioning of marine ecosystems, thanks to their high abundance and taxonomical diversity, fast turnover and metabolic rates. Some meiofaunal taxa have also revealed their considerable utility in the evaluation of the ecological quality of coastal marine sediments in accordance with European Directives. Therefore, understanding the distribution patterns of their biodiversity and identifying the factors that control it at a global level and in different types of habitats is of great importance. Due to their very small morphological characteristics utilized for the taxonomical identification of these taxa, the suite of necessary skills in taxonomy, and the general taxonomic crisis, many young scientists have been discouraged to tackle meiofauna systematics. The papers collected in this book, however, bring together important themes on the biology, taxonomy, systematics, and ecology of meiofauna, thanks to the contribution of researchers from around the world from the USA, Brazil, Costa Rica, Mexico, Cuba, Italy, Belgium, France, Denmark, Russia, Kuwait, Vietnam, and South Korea. This was certainly an additional opportunity to build a more solid network among experts in this field and contribute to increasing the visibility of these tiny organisms. A special thanks to Prof. Wonchoel Lee for the wonderful taxonomic drawings of the species described in this volume that contribute to make our cover unique