ALBERT

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 197〈/p〉 〈p〉Author(s): P. Bohorquez, P.J. Jimenez-Ruiz, P.A. Carling〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In this work, we present a whole system model of megafloods from catastrophic ice-dam failure in the late Pleistocene that comprises the study of the dynamics of the glacial lake, the propagation of the flood wave downstream of the dam, and an approximation to the ice breach process. The ice-dam incision rate was simply considered an unknown constant, which was varied systematically to best fit the maximum altitude of the simulated water surface and the paleostage indicators in the downstream valley during the transient megaflood. Hence, the hydrograph resulting from the breach of the ice dam was not prescribed but was an output of the paleohydraulic reconstruction.〈/p〉 〈p〉By considering two possible configurations of the breach in the ice dam, i.e. full or partial removal of the ice, we constrained the incision rate in the narrow range of 28 − 42 m ⋅ h〈sup〉−1〈/sup〉. Two connected glacial lakes, Kuray and Chuja, released 95% of the stored water volume (i.e., 564 km〈sup〉3〈/sup〉) in 33.8 hours. A peak discharge of 10.5 M m〈sup〉3〈/sup〉 ⋅ s〈sup〉−1〈/sup〉 was required to form numerous giant bars and run-up deposits in the Chuja and Katun valleys. The peak streamflow occurred after 11 h when 45% of the available lake volume had been evacuated from the Kuray and Chuja basins. Further verification of the reconstructed megaflood was achieved by studying the computed hydraulic conditions during the lake draining that justify the existence and orientation of several fields of subaqueous gravel-dunes in the glacial lake. Complex spatiotemporal patterns during the recession stage of the flood built most of the fields of bedforms. In terms of nondimensional parameters, the Froude and Shields numbers that formed the dune fields were similar to those observed in large sandy rivers, but the flow was undoubtedly unsteady and two-dimensional.〈/p〉 〈p〉We conclude by noting that the extensions of the simulated area cannot be cropped or analysed by independent parts in order to predict the formation of the most relevant geological records due to the unsteady, two-dimensional nature of the flow motion and the development of backwater effects in the drainage network. Lastly, the paleohydrological reconstruction of a megaflood has helped not only to infer the dynamics of the event but also to retrodict the mean parameters of the ice-dam failure mechanism.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 2 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews〈/p〉 〈p〉Author(s): A. Laborde, L. Barrier, M. Simoes, H. Li, T. Coudroy, J. Van Der Woerd, P. Tapponnier〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With its central position between the Tibetan Plateau and the Tian Shan Range, the Tarim Basin is a key element of the Cenozoic Asian orogenic system. However, a comprehensive regional study, and more particularly the quantification of shortening through this basin and its margins, are still needed to understand its role in the Cenozoic deformation of Asia. From a compilation of previous works, together with an extensive dataset of satellite, field, seismic and well data, we provide a tectonic map of the Cenozoic structures and four balanced geological transects of the Tarim Basin and its surrounding ranges. Based on this map and these cross-sections, we characterize the Cenozoic deformation of the original Proterozoic Tarim block. From structural restorations and crustal budgets, we also quantify the compressive component of this deformation. Most of the Cenozoic compressive deformation (from ~94% to 100%) is concentrated in the ranges along the block margins. To the west, up to 78 ± 23 km and 54 + 24/−18 km of crustal shortening are accommodated across the compressive Western Kunlun and Southwestern Tian Shan ranges, while to the east, up to 38.6 ± 18 km and 15 + 20/−15 km are accommodated across the transpressive Altyn Tagh and Southeastern Tian Shan ranges. A non-negligible amount of compressive deformation (up to ~6%) is also accommodated within the Tarim Basin by large basement-cored uplifts with a vergence synthetic to the deformation of the Tibetan Plateau edge. To the west, the Bachu uplift absorbs ~5 km of the total crustal shortening of the Western Kunlun thrust system, while to the south, the Tanan uplift accumulates ~0.6 km of the Altyn Tagh strike-slip system. Structural inheritance has a major influence on the Cenozoic deformation since ~33.3% to 100% of the total shortening is accommodated by reactivated basement structures inherited from the Protero-Paleozoic history of the Tarim block. Finally, we argue that the basement-cored uplifts in the centre of the basin imply a deformation transfer from the Tibetan Plateau to the Tian Shan, above a deep crustal decollement decoupling the deforming crust from an underlying rigid mantle.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Lalu Das, Jitendra Kumar Meher〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Himalayas popularly known as the ‘Third Pole’ and ‘Water tower’ of Asia has attracted global attention under the context of climate change as rainfall in this region has decreased drastically, and temperature has risen very rapidly in the last century. Present study was attempted to quantify such abnormal warming and unexpected declining trend of rainfall vis-à-vis to identify factors influencing such abnormal behavior over the complex physiographical region technically known as Western Himalaya Region (WHR) through the available literature therein. It was revealed that frequency and intensity of extreme rainfall and temperature events have risen due to the variation of local weather events while mean climate has altered due to the influence of large-scale circulations like the Indian monsoon, Western Disturbances, and change in teleconnection pattern. Why the WHR has been a hotspot of several hazards like the cloudburst, Glacial Lake Outburst Flood (GLOF), convective storms, and forest fires in the past have been answered with appropriate evidence. Feedback from different atmospheric factors like snow-albedo, black carbon, and other suspended particulates was discussed in details to understand the complex nature of the Himalayan climate. WHR may face higher magnitude of heavy and extreme rainfall because of its accelerated warming. Information assembled in the present paper will be considered as a valuable resource document for the remote and vulnerable geographical locations of WHR, where research and developmental activities lag due to unavailability of adequate data and its quality and insufficient information and its proper access in a concise form.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 22 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews〈/p〉 〈p〉Author(s): Guangyou Zhu, Zhiyao Zhang, Xiaoxiao Zhou, Tingting Li, Jianfa Han, Chonghao Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Most Paleozoic marine craton basins in China are rich in natural gas except the Tarim Basin, where both oil and gas are prolific. Various hydrocarbon types have been found in this basin, including deep ultra-heavy oil, heavy oil, normal oil, volatile oil, condensate and natural gas. Petroleums with diverse types even coexist within a single reservoir. Generally, the Ordovician and Cambrian reservoirs are deeply buried (5500–8000 m) and intensively altered after initial oil and gas accumulations, bringing challenges to physical property prediction before drilling and evaluation of exploration target. Based on recent exploration discoveries and experimental data, we systematically analyzed the origin of oil and gas, demonstrated the mechanisms and processes of secondary geochemical alteration (e.g. biodegradation, gas washing fractionation, TSR and high-temperature cracking). Moreover, the preservation mechanism of ultra-deep normal oil was also clarified, and the distribution patterns of oil and gas were predicted. Tarim Basin has been uplifted and shallowly buried in the early accumulation stage, then rapidly and deeply buried in the late stage, resulting in various geochemical alteration processes at different burial stages. Through the reconstruction of complicated deep-strata oil and gas accumulation histories, the spatial distribution of deep petroleum types were predicted. This review has provided detailed assessment with case studies in the Tarim Basin, and sheds light on the preservation mechanisms and the alteration processes of deep liquid petroleums. In addition to massive gas accumulations, liquid oils still have great exploration potential in strata deeper than 8000 m in the Tarim Basin.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Makeely I. Blandford, Mohammad Katouli, Ben L. Gilby, Christian O'Dea, Andrew D. Olds, Thomas A. Schlacher〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dead animal bodies occur naturally in ecosystems, are regularly washed up along ocean beaches, and are a key component of many coastal food webs where scavenging animals consume carcasses. Microbes that decompose carcasses can, however, produce toxic chemicals during putrefaction. This is frequently assumed to have negative consequences for scavengers in the wild, but has been rarely quantified. In this study, we measured how changes in the microbial assemblages of decaying fish affect the toxicity of carcasses. We did this by allowing fish carcasses to decompose in the field for up to 31 days in the dunes of a sandy beach; an ecosystem where scavenging animals are common. Carcasses were sampled daily and the tissues tested for changes in culturable microbial communities using 100 μL samples of whole carcass homogenates on marine and sheep blood agar, and changes in cytotoxicity using Vero cell assays. Cytotoxicity peaked 11 days after deployment showing 95% rounded and detached cells. Cytotoxicity was lower in the early phases of decay as microbial communities developed and after approximately two weeks when carcasses dried. The peak in toxicity correlated with peaks in the abundance of 〈em〉Acinetobacter〈/em〉, and 〈em〉Vibrio〈/em〉 and 〈em〉Alivibrio〈/em〉; microbes known to produce toxins. This trajectory of toxicity suggests an ecological model where microbes may predictably determine the palatability of carrion in food webs, making both fresh and aged carcasses the least risky proposition for scavenging animals. This ‘fresh and aged carcasses are best’ model is highly amenable to testing in the context of carrion-centred food webs in multiple systems, and it has practical applications in conservation where animal carcasses are provided to threatened, and often iconic, scavenger species.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771418310059-fx1.jpg" width="311" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Katerina Kombiadou, Susana Costas, A. Rita Carrasco, Theocharis A. Plomaritis, Óscar Ferreira, Ana Matias〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Resilience has been used over a wide range of scientific fields and often ambiguously, causing confusion over terminology and concepts and giving rise to distinct interpretations and misconceptions, even within the same scientific discipline. Starting by providing clarifications and definitions of the main terminology and key principles of ecological resilience theory, we pass on to expressing them through geomorphic dimensions of barrier islands. Three distinct environments (beach, dune, marsh) are proposed as the panarchical levels of analysis, along with potential feedbacks between them and geomorphic dimensions that can express the changes of the stability landscape. Morphological changes induced by storms and subsequent recovery are transferred to stability landscapes, over a range of storm impacts and recovery. We postulate that post-perturbation recovery should not be restricted to regaining pre-disturbance barrier dimensions, but should be viewed in terms of reorganisation and adaptation, accounting for maintaining the existence of functions, or the ability of the system to regain them. The proposed scheme and dimensions are tested using geomorphological data from barrier response to distinct disturbances, over different temporal scales that range from event to multi-decadal ones. The case of a barrier island migrating landwards is conceptualised in terms of alternative states and thresholds arising during the process and related phases and changes to the adaptive cycle. The methodology and approach presented is a step towards more holistic views of geomorphic systems' resilience that we hope will contribute to furthering interdisciplinary understanding and cooperation in the area of sustainability and resilience of natural systems.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0012825219302077-ga1.jpg" width="227" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Anastasia G. Yanchilina, William B.F. Ryan, Timothy C. Kenna, Jerry F. McManus〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Deglaciation of the Eurasian Ice Sheet dispensed vast amounts of meltwater laden with red-brown clay into Black and Caspian Sea's freshwater lakes between 16,350 and 15,400 calendar years BP. The arriving sediment had a mineral composition and strontium-neodymium isotope signatures (〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr, and ε〈sub〉Nd〈/sub〉) consistent with the crystalline bedrock that lay beneath the ice sheet as opposed to sources from landscapes crossed by the rivers that carried meltwater to the lakes. The magnitude and rapidity of the shifts of 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr and δ〈sup〉18〈/sup〉O in shells of ostracods and mollusks, an eight-fold increase in sediment accumulation rate, and a plunge of 1250 〈sup〉14〈/sup〉C years in the radiocarbon reservoir age indicate a volume of meltwater sufficient to have replaced most or all of the pre-existing lake water. If the release of 〉25,000 km〈sup〉3〈/sup〉 of water from the Caspian into the Black Sea's New Euxine Lake was abrupt by judging the magnitude of erosion in the floor of the Manych Strait spillway, this event qualifies as a megaflood. Deeply-scoured furrows, channel floor bars, and swaths of mounds 5–20 km in length and 5–20 m in height are reminiscent of scabland landscapes. The meltwater is coincident with Heinrich Stadial 1 when the Alpine and Eurasian ice sheets re-advanced and temperatures of the Black Sea's lake surface remained cold. Sand grains within the red-brown clay indicate they were transported by lake surface ice.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 197〈/p〉 〈p〉Author(s): Yong Ge, Yan Jin, Alfred Stein, Yuehong Chen, Jianghao Wang, Jinfeng Wang, Qiuming Cheng, Hexiang Bai, Mengxiao Liu, Peter M. Atkinson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The properties of geographical phenomena vary with changes in the scale of measurement. The information observed at one scale often cannot be directly used as information at another scale. Scaling addresses these changes in properties in relation to the scale of measurement, and plays an important role in Earth sciences by providing information at the scale of interest, which may be required for a range of applications, and may be useful for inferring geographical patterns and processes. This paper presents a review of geospatial scaling methods for Earth science data. Based on spatial properties, we propose a methodological framework for scaling addressing upscaling, downscaling and side-scaling. This framework combines scale-independent and scale-dependent properties of geographical variables. It allows treatment of the varying spatial heterogeneity of geographical phenomena, combines spatial autocorrelation and heterogeneity, addresses scale-independent and scale-dependent factors, explores changes in information, incorporates geospatial Earth surface processes and uncertainties, and identifies the optimal scale(s) of models. This study shows that the classification of scaling methods according to various heterogeneities has great potential utility as an underpinning conceptual basis for advances in many Earth science research domains.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 197〈/p〉 〈p〉Author(s): Heather A. Stewart, Alan J. Jamieson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The exact location and depth of the deepest places in each of the world's oceans is surprisingly unresolved or at best ambiguous. Out of date, erroneous, misleading, or non-existent data on these locations have propagated uncorrected through online sources and the scientific literature. For clarification, this study reviews and assesses the best resolution bathymetric datasets currently available from public repositories. The deepest place in each ocean are the Molloy Hole in the Fram Strait (Arctic Ocean; 5669 m, 79.137° N/2.817° E), the trench axis of the Puerto Rico Trench (Atlantic Ocean; 8408 m 19.613° N/67.847° W), an unnamed deep in the Java Trench (Indian Ocean; 7290 m, 11.20° S/118.47° E), Challenger Deep in the Mariana Trench (Pacific Ocean; 10,925 m, 11.332° N/142.202° E) and an unnamed deep in the South Sandwich Trench (Southern Ocean; 7385 m, 60.33° S/25.28° W). However, discussed are caveats to these locations that range from the published coordinates for a number of named deeps that require correction, some deeps that should fall into abeyance, deeps that are currently unnamed and the problems surrounding variable and low-resolution bathymetric data. Recommendations on the above and the nomenclature and definition of deeps as undersea features are provided.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Camille Le Guen, Samuele Tecchio, Jean-Claude Dauvin, Gwenola De Roton, Jérémy Lobry, Mario Lepage, Jocelyne Morin, Géraldine Lassalle, Aurore Raoux, Nathalie Niquil〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉During the last decades, the highly-anthropized Seine estuary has been impacted by modification of its habitats (building of a major extension of Le Havre harbour, i.e. Port2000) and a significant natural decrease in freshwater discharge. A Before/After analysis, using a toolbox of indicators, was applied to characterize the effects of both events on the estuarine ecosystem status. We selected from existing tool boxes several indicators derived from food web modelling or community composition data, such as biodiversity indicators, a guild-based index (〈em〉i.e.〈/em〉 Estuarine and Lagoon Fish Index ELFI) and ecological network analysis (ENA) indices. ENA and biodiversity indicators were applied on six spatial boxes describing the Seine estuary and its outlet. Results showed an increase in taxonomic and functional richness over time, mainly due to marinisation, and significant changes in food-web properties in relation to Port2000. ENA indices appeared as a promising method in ecological status assessment, especially for estuaries considered as inherently disturbed.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419300484-fx1.jpg" width="253" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): A. Rosa, S. Cardeira, C. Pereira, M. Rosa, M. Madureira, F. Rita, J. Jacob, A. Cravo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Understanding the mass exchange patterns between coastal lagoons and ocean plays a key role to explain their impact upon the water quality and biological productivity of these systems. Ria Formosa is a temperate lagoon on the southwestern coast of Iberia, one of the most important coastal system in this region in terms of biological productivity, ecological and economic values. Given its relevance and strong interconnectivity with the adjoining ocean, the quantification of these exchanges is a key issue that had not yet been thoroughly addressed. In this context, this study is focused on understanding the role of Ria Formosa's main inlet in terms of mass budgets dynamics of water, nutrients, suspended solids and chlorophyll 〈em〉a〈/em〉 with the Atlantic Ocean and to identify its seasonal variability. In order to attain this purpose, the influence of the forcing mechanisms at different time scales, including tides, oceanographic/meteorological synoptic conditions and seasons, was assessed. To accomplish this, six semidiurnal tidal cycles surveys were conducted at Faro-Olhão inlet, comprising hourly water samples collection and 〈em〉in situ〈/em〉 measurements at a selected cross-section of the inlet channel. Results revealed that mass exchanges variability through Faro-Olhão inlet was mainly due to oceanographic processes (upwelling and coastal countercurrent events) and, secondly, to phytoplankton activity within the lagoon. Seasonally, regardless the direction of the residual current through the inlet, Ria Formosa acted as a source of material during Spring and Summer seasons, which contributed to increase the biological productivity of the coastal ocean. Upwelling events that occurred more evidently during the Autumn survey drove an import amount of nutrients into the lagoon, enhancing its biological productivity. Furthermore, the rainfall period that prevailed before the Winter survey contributed to export material and nutrients to the adjacent ocean, confirming that Ria Formosa fertilizes the coastal ocean, even during a period of low productivity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Marco Camarda, Sofia De Gregorio, Giorgio Capasso, Roberto M.R. Di Martino, Sergio Gurrieri, Vincenzo Prano〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Natural soil CO〈sub〉2〈/sub〉 emissions constitute a substantial portion of the carbon emitted in the atmosphere, particularly in volcano-tectonic areas where deep CO〈sub〉2〈/sub〉 supply is also present because of the Earth's degassing. Hence, these emissions are considered of fundamental importance in the study of global CO〈sub〉2〈/sub〉 budget estimates. Furthermore, in recent years, soil CO〈sub〉2〈/sub〉 emissions have played an important role in the realm of seismic and volcanic studies as well as in the mitigation of gas-hazard-related risks. Although many methods are available for monitoring soil CO〈sub〉2〈/sub〉 emissions, the comprehension and use of monitoring data can be challenging. This is because soil CO〈sub〉2〈/sub〉 emissions are influenced by numerous processes and as consequence exhibit high spatio-temporal variability. In this framework, understanding the processes behind the variability of soil CO〈sub〉2〈/sub〉 emissions is instrumental in improving their investigations. In addition, more suitable management of the monitoring data series is another crucial aspect of soil CO〈sub〉2〈/sub〉 emission studies. In this study, we provide a detailed description of the processes that affect soil CO〈sub〉2〈/sub〉 emissions and outline their impacts as functions of different features of the measurement sites. In particular, we examine the processes driven by both exogenous and endogenous factors and explain the origin of the observed variations. This study is based on the data acquired via eight monitoring stations on the island of Vulcano (Italy) from 2009 to 2017. The monitoring sites exhibited different features and covered a wide range of the soil CO〈sub〉2〈/sub〉 emission values, thereby allowing a broad application of the obtained results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Alicia Fantasia, Thierry Adatte, Jorge E. Spangenberg, Eric Font, Luís V. Duarte, Karl B. Föllmi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Toarcian Oceanic Anoxic Event (T-OAE, ~ 183 Ma) was an episode of extreme warmth, environmental changes and carbon cycle perturbation. We present a high-resolution study of the Peniche section (Lusitanian Basin, Portugal), recently defined as the Toarcian Global Stratotype Section and Point, to provide a review of the Pliensbachian–Toarcian (Pl–To) environmental and climatic changes. A large ~7‰-negative carbon-isotope excursion (CIE) is recorded within the T-OAE interval in bulk organic matter. Distinct small-scale 〈em〉δ〈/em〉〈sup〉13〈/sup〉C negative shifts, modulating the T-OAE carbon isotope signal, are correlated across different European basins, which have implications on the estimation of the T-OAE duration. The increase in kaolinite content and chemical index of alteration from the Pl–To boundary up to the T-OAE interval is interpreted as reflecting a shift towards warmer and wetter climate conditions. The common occurrence of coarse-grained turbidites within the T-OAE interval is possibly linked with changes of the hydrological cycle and storm intensity. Low total organic carbon contents together with the absence of redox-sensitive trace element enrichments indicate oxygen-deficient conditions unfavourable for organic matter preservation. Mercury data show a clear increase at the base of the T-OAE CIE followed by a return to background values, providing further evidence that Karoo-Ferrar volcanism might have triggered the series of environmental disturbances during the early Toarcian. However, the highest mercury values are recorded in samples containing abundant pyritized wood fragments, highlighting the influence of local chemical processes on mercury enrichments, which should be considered before any interpretation of the Hg records.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 14 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Luis G. Egea, Cristina Barrón, Rocío Jiménez–Ramos, Ignacio Hernández, Juan José Vergara, José Lucas Pérez–Lloréns, Fernando G. Brun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The knowledge of the production and carbon transference dynamics between adjacent communities is essential to gain a better understanding on the role of coastal areas in the global carbon cycle. Here, we assess the carbon metabolism (through dissolved oxygen –DO– concentration) and the net dissolved organic carbon (DOC) fluxes for benthic (dominated by the seagrass 〈em〉Cymodocea nodosa〈/em〉, the rhizophytic green algae 〈em〉Caulerpa prolifera〈/em〉 and unvegetated sediments) and pelagic plankton communities co〈em〉–〈/em〉habiting the same shallow coastal area in Cadiz Bay, southern Spain. Both the seagrass and macroalgae meadows were highly autotrophic, but the carbon metabolism of 〈em〉C. prolifera〈/em〉 community shifted seasonally from net autotrophic to net heterotrophic. Unvegetated benthic communities were slightly heterotrophic throughout the year, while plankton community was net autotrophic. This study reveals how the different components of the ecosystem (i.e. macrophyte, sediment or plankton community) may have a seasonal variability in the contribution to the NCP in shallow coastal areas. Moreover, our results suggest that pelagic communities can be essential to maintain autotrophy of coastal system during periods of low benthic productivity. Regarding DOC, benthic communities were net DOC producers, undergoing a marked seasonality with maximum net DOC production during summer. This indicated an extra carbon assimilation not usually contemplated in productivity studies, which entails an underestimation of gross production in these communities. A strong relationship between net DOC flux and net community production (NCP) was found for the three benthic communities. The plankton community was a net DOC consumer indicating a strong coupling between the benthic and pelagic compartments in the bay. When up〈em〉–〈/em〉scaling our results to the whole bay, the NCP estimated for the benthos was 8800 ± 3770 Tons C y〈sup〉−1〈/sup〉, and the net DOC flux was 2465 ± 830 Tons C y〈sup〉−1〈/sup〉, which were mainly due to vegetated communities, indicating the importance of coastal vegetated benthic ones in the carbon metabolism and DOC fluxes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771418304578-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): John W. Day, Gary P. Shaffer, Donald R. Cahoon, Ronald DeLaune〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Canals and spoil banks have contributed significantly to high rates of wetland loss in the Mississippi Delta. There has been relatively little research on management of canals and spoil banks and this needs to be a significant component of restoration of the delta. We analyze research on the role of backfilling canals in the context of delta restoration with special reference to Turner and McClenachan (2018) who state that if all canals were backfilled, it could significantly reduce or even reverse wetland loss and that most wetland loss is caused by canals. We agree with Turner and McClenachan that canals have been a significant cause of wetland loss in the Mississippi Delta and that removing spoil banks and backfilling canals should be an integral part of delta restoration. However, a number of factors need to be considered when choosing which canals to backfill including possible enhanced erosion due to exposure to wave action for newly created and remnant marsh, the current and future production history of oil and natural gas wells associated with canals, and other restoration activities in oil and gas fields. Turner and McClenachan's analysis using wetland loss patterns in 15-min quadrangles suggesting that canal density can explain most wetland loss in coastal Louisiana is flawed because of scale problems and other impacts of oil and gas activity. These impacts include subsurface induced subsidence and the impact of produced water and toxins on wetlands that are largely unrelated to surface alteration due to canals and spoil banks.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Yury I. Klyukin, Matthew Steele-MacInnis, Pilar Lecumberri-Sanchez, Robert J. Bodnar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fluid inclusions are the best tool to characterize the properties of fluids in paleo-geological environments, and the most widely used methods applied to fluid inclusions are petrographic analysis and microthermometry. Here, we present a comprehensive review of the phase characteristics of fluid inclusions, represented by the binary system H〈sub〉2〈/sub〉O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉NaCl, from ambient temperature to homogenization. We quantify the changes in compositions, densities and volume fractions of liquid, vapor and halite as temperature is increased. Fluid inclusions of any bulk density, salinity, or homogenization behavior show a decrease in the volume fraction of vapor (i.e., shrinkage of the bubble) during heating to ~400 °C. For fluid inclusions that homogenize to vapor, this leads to a phenomenon referred to in previous studies as “homogenization by inversion,” wherein the volume fraction of vapor decreases during heating to ~380 °C, and increases with continued heating thereafter. Inclusions with salinity less than ~10 wt% NaCl show a rapid increase in volume fraction of vapor with heating above ~380 °C, and plateau at 〉90 vol% vapor, leading to apparent homogenization at temperatures well below the actual homogenization. Inclusions containing a fluid with the critical density may exhibit reversals in the volume fraction of vapor during heating. Inclusions having the critical density and low salinities will generally homogenize by fading of the meniscus while the volume fraction of vapor is quite low (〈10 vol%) and may be misinterpreted as homogenizing to the liquid. These results aid in understanding and interpreting petrographic and microthermometric observations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Allen P. Nutman, Vickie C. Bennett, Clark R.L. Friend, Martin Van Kranendonk〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Eoarchean (〉3600 Ma, or millions of years ago) folded and metamorphosed Isua supracrustal belt and the adjacent orthogneiss exposures of Greenland contain rare low deformation lenses that display some uniquely-preserved components of Earth's oldest rock record. These include world's oldest (but contested) stromatolites in dolomitic carbonates, conglomerates, pillow basalts demonstrating submarine eruption, slivers of upper mantle rocks, formation of earliest continental crust by multistage tonalite + diorite emplacement followed by intracrustal granite production. All these diverse occurrences are keys to establish early Earth's processes at the start of the geological record. Although some of these features are preserved at several localities, other critical ones are exposed on only a few m〈sup〉2〈/sup〉 of rock at single localities or are of historical significance. None of these sites are currently protected, and there is a reliance on responsible sampling to keep them intact for future generations. Given the high interest in the Archean Eon, combined with the increased ease of fieldwork in remote localities, many significant ‘Deep Time’ localities in not only Greenland but worldwide are in danger of eradication. Here, five key Isua area geological sites are presented, with an explanation of their significance and worthiness for initially reliance on already-collected samples, but hopefully ultimately government protection. This highlights an increasing problem of destruction of in situ evidence of Earth's unique early geological heritage and the need for collaboration in protecting and archiving of these key scientific resources.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews〈/p〉 〈p〉Author(s): Lara F. Pérez, F. Javier Henández-Molina, Emanuele Lodolo, Fernando Bohoyo, Jesus Galindo-Zaldívar, Andrés Maldonado〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Scotia Sea is a complex geological area located in the Southern Ocean which evolution is closely linked to the opening of the Drake Passage. Structural highs of continental nature derived from the former continental bridge between South America and the Antarctic Peninsula surround the abyssal plains of the Scotia Sea, restricting small isolated sedimentary basins along its southern margin. Morpho-structural and seismo-stratigraphic analyses of multichannel seismic reflection profiles, and additional geophysical data available in the region, have been conducted, decoding regional and global implications of the basins' evolution. The main aim of this work is to describe the stratigraphic evolution of the southern Scotia Sea basins, from their opening in the back-arc tectonic context of the Scotia Sea, to the last oceanographic changes which have carried on global climatic implications. The evolution of the south Scotia Sea occurred through two major tectonic stages registered in the sedimentary record of the region: 1) the end of the subduction in the northwest part of the Weddell Sea during the early Miocene, which shortened the back-arc subduction trench generating a major change in the regional tectonic field that determined the evolution of the southern basins towards two different types of passive margins: magma-poor and magma-rich; and 2) the full development of the southern Scotia Sea basins during the middle Miocene, that led to the opening of deep oceanic gateways along the South Scotia Ridge. Interplay among tectonics, oceanography and climate is proposed to control the regional sedimentary stacking pattern, with coeval changes globally identified.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews〈/p〉 〈p〉Author(s): David Fernández-Blanco, Gino de Gelder, Robin Lacassin, Rolando Armijo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This review shows how collective analysis of morphotectonic elements on uplifting rift margins can constrain the mechanical behaviour of continents during early rifting. This is shown for the modern Corinth Rift, one of the fastest-extending and most seismically active continental regions worldwide. We reconstruct the growth of the normal fault system that accommodates most of this strain and the uplift of the rift margin it bounds, from onset to present and at rift scale. Our approach provides first-order constraints on the mechanics and evolution of the rift, and can be used in other areas of early continental rifting.〈/p〉 〈p〉We review and re-assess known geologic evidence in the Corinth Rift, and compile morphotectonic elements into a new map. We analyse the rift topo-bathymetry, and the footwall relief, river catchments and tectonic knickpoints in its uplifting margin. We also review studies that constrain the growth of normal faults using morphotectonic elements in their footwall, and propose a novel theoretical framework to reconstruct fault time-evolution during early rifting. We couple known and new data to derive fault displacement profiles in time, and use the theoretical framework to infer the history of growth and linkage of rift border faults, in turn restricting rift growth mechanics and evolution.〈/p〉 〈p〉Our rift-scale morphotectonic investigation shows that the current rift-bounding faults are kinematically coherent at depth and constitute a fault 〉80 km in length. This composite master fault grew along-strike from the rift centre, linking and integrating individual fault segments that developed co-linearly at younger times. The observed fault elastic flexure, footwall relief wavelength and high uplift and slip rates throughout the rift margin suggest the border fault is steep and highly localized in strain, and transects the entire seismogenic layer growing in a long-term strong elastic lithosphere.〈/p〉 〈p〉Integration of previous and own findings suggest the Corinth Rift evolved in two distinct extensional phases. These extensional phases are delimited by the fast, overwriting growth of the new rift-forming fault, that switched rift mechanics in a ~300 kyr timespan, and controls rift evolution thereafter. The new rift-forming fault enlarges the modern rift as an asymmetric half-graben, along and across strike, superimposed onto the preceding ~4 My distributed extension.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Rosalía Aguilar-Medrano, John R. Durand, Víctor H. Cruz-Escalona, Peter B. Moyle〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Estuarine fish assemblages are undergoing rapid change due to invasions of non-native species and physicochemical alteration of their habitats. Here, we examine the novel fish assemblages of the upper San Francisco Estuary (SFE) by first placing the fishes into ecological assemblages (EAs) of species that co-occur based on salinity, macrohabitat, and diet. We then used the morphological characteristics of each species to place them into functional groups (FGs) or potentially functionally independent species (FIS). Our question was: are there native and non-native species that occupy a similar niche in ecomorphological space, and thus potentially interact? Then, based on our results, we sought to understand if there is evidence that native species are being displaced by non-native species. The 43 species examined were placed into 17 EAs of potentially interacting species. Within these EAs, we identified 13 FGs and 13 FIS based on ecomorphology. Six FGs contain both native and non-native species indicating organization independent of the origin of the species. However, in most cases the native species were present in low abundance or were in categories of risk. Five FGs contained just non-native species that were found mainly in altered habitats and two FGs contained just native species. Overall, both native and non-native species appear to form a novel assemblage, although the decline of some native species in the face of potential competitors and predators suggests the final assemblage has not yet been determined. In addition, ongoing alterations of the SFE ecosystem increase the likelihood that invasions of new species will continue, causing further changes to the assemblage.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): H. Jimenez, A.L. Chang, G.M. Ruiz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Macrobenthos is used commonly in disturbance-related studies of coastal ecosystems, including those that evaluate invasions by non-native species (NIS), but still little is known about temporal variation in community characteristics, especially in bays and estuaries. In this study we investigated inter-annual changes in the soft-sediment benthic communities of San Francisco Bay over a period of five years, evaluating the contribution of NIS vs. native species to community attributes (species richness, abundance) and the efficacy of sampling (percent richness detected for each NIS and native species). Benthic macrofauna were collected, identified, and quantified from 10 stations (48–50 replicate samples) per year across the high salinity region of the Bay. A total of 36,872 individuals belonging to 126 morphospecies were collected; 61 species were native, accounting for 22% of total abundance, and 31 species were NIS, which reached 74% of total abundance. The other 34 species were either cryptogenic or unresolved taxa. Soft-sediment communities were mainly comprised of amphipods (〈em〉Ampelisca abdita〈/em〉, 〈em〉Sinocorophium heteroceratum〈/em〉, 〈em〉Monocorophium acherusicum〈/em〉), polychaetes (〈em〉Sabaco elongatus〈/em〉, 〈em〉Euchone limnicola〈/em〉) and bivalves (〈em〉Venerupis philippinarum〈/em〉). Community structure and composition were stable across years during the period of the study, despite a major marine heat wave and a record-breaking drought that raised average salinity levels for several years. The sampling was effective, especially for NIS, detecting a higher proportion (94–100%) of estimated richness for NIS compared to native species (74–89%) across the five year period, suggesting NIS were more evenly distributed in space and time and many native species occurred more patchily and less frequently.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771418310485-fx1.jpg" width="492" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Changyou Wang, Rongguo Su, Laodong Guo, Bin Yang, Ying Zhang, Lei Zhang, Hui Xu, Wenjie Shi, Lansu Wei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nutrient pollution and algal blooms in coastal waters have long been a major concern, and understanding the response of algae to nutrient dynamics is thus essential. The minimum concentration under which 〈em〉Ulva prolifera〈/em〉 will not grow, estimated from a nutrient-alga coupling model developed in this study, was 6.5 μmol L〈sup〉−1〈/sup〉 for nitrate and 0.27 μmol L〈sup〉−1〈/sup〉 for phosphate. The model was parameterized with cultural experiments to examine the effects of nitrate and phosphate on the growth of 〈em〉Ulva prolifera〈/em〉 and the development of green tide. The cultural experiments showed that flux of nitrate absorbed by 〈em〉Ulva prolifera〈/em〉 increased significantly with the concentration of nitrate or phosphate, which followed the Michaelis-Menten equation, while the flux of phosphate linearly increased with its concentrations. Nitrate concentrations at 〉25 μmol L〈sup〉−1〈/sup〉 had little influence on the absorption of phosphate, but compensating absorption of phosphate occurred when the nitrate concentration was below 15 μmol L〈sup〉−1〈/sup〉. Phosphate concentrations had a remarkable enhancement to the absorption of nitrate when phosphate concentration was 〈1.4 μmol L〈sup〉−1〈/sup〉. The absorption rates of nitrate and phosphate by 〈em〉Ulva prolifera〈/em〉 followed the same variation trend as nutrient absorption fluxes. The increase in nitrate absorption rates has a limited impact on the relative growth rate of 〈em〉Ulva prolifera〈/em〉, while the increase in phosphate absorption rates has a marked impact on the relative growth rate. Our results provide new insights into the growth mechanism of 〈em〉Ulva prolifera〈/em〉 and the development and evolution of green tides in coastal marine environments. Applications of our model should help governmental agencies in environmental remediation and policy making.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 3 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Alethea S. Madgett, Kyari Yates, Lynda Webster, Craig McKenzie, Colin F. Moffat〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Scotland's marine food webs support a diversity of species and habitats. They contribute to maintaining the balance of the natural environment. Previous studies show that these ecosystems are contaminated by persistent organic pollutants and trace metals; with animals in higher trophic levels (e.g. cetaceans and pinnipeds) containing concentrations that are among the highest found in the ocean. Contaminants represent one of many pressures to which species and habitats are exposed. In assessing the contribution of contaminants to the overall pressure, measuring contaminants at a specific trophic level and then using trophic magnification factors (TMFs) to estimate concentrations at other trophic levels permits assessments across the food web, as well as allowing the adjustment of contaminant concentrations to a particular trophic level for comparison to assessment criteria. Fatty acid (FA) signatures and stable isotope (SI) ratios were used to develop a picture of Scottish marine food web ecology and reliably ascribe trophic levels to a wide range of species. Fatty acid trophic markers (FATMs) were used as trophic level indicators and with SI analysis, permitted identification of the mean trophic level of each species and determination of the feeding patterns and predator-prey relationships existing in the Scottish marine food web. Two hundred and eleven (211) samples comprising of seven fish species, one shark species, fourteen marine invertebrate species, three marine mammal species and two zooplankton species from different locations around Scotland were found to have mean trophic levels ranging from 1.47 ± 0.11 in zooplankton to 5.02 ± 0.35 in harbour seal. Fatty acid profile showed specific dietary information which differed between the eleven taxonomic classes and twenty-seven species. The organic and inorganic contaminant concentrations of the species for which trophic level has been determined, together with TMFs, will be reported in future papers.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419300411-fx1.jpg" width="210" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 31 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science, Volume 227〈/p〉 〈p〉Author(s): Martin Lykke Kristensen, David Righton, Diego del Villar-Guerra, Henrik Baktoft, Kim Aarestrup〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We tagged 125 sea trout kelts (460–925 mm) in seven Danish rivers with positively buoyant DSTs. Fifty-three (42%) tags were recovered, enabling a comparison of behaviour in kelts that survived the marine period and kelts that did not. Data revealed an estimated mean survival time at sea of 14.3 days (range 1–65 days) for fish that died at sea. Fish that did not survive had lower weight/length ratios when tagged than survivors (P = 0.005) but exhibited a similar diel diving pattern while at sea. Both surviving and non-surviving fish gradually increased diving activity and the daily visited maximum depths after sea entry, but some performed fewer dives and resided in shallower depths than others. This difference was pronounced when comparing surviving fish (most active divers) with fish caught by anglers (least active divers). The results show that the first weeks at sea are critical for kelt survival and that physical status of kelts may affect behaviour and probability of survival. The preference for shallower waters and less diving activity in some individuals indicate that coastally based fisheries and recreational angling may select against specific behavioural phenotypes which should be investigated more intensively.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419301362-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 31 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Mochamad Furqon Azis Ismail, Joachim Ribbe〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Western boundary currents are characterized by high mesoscale eddy activity including that of cyclonic frontal eddies (CFEs). These form frequently adjacent to the shelf-break, export coastal water and affect biological productivity. Here, we study the physical properties of eddies identified within the intensification zone of the East Australian Current (EAC) through the analysis of remotely sensed data, the application of an ocean circulation model and the evaluation of Lagrangian simulations during austral winter 2007. We examine the spatial and temporal evolution of identified eddies, investigate their formation mechanism, and quantify the contribution made to cross-shelf exchanges. The mesoscale eddies are tracked from generation to decay using an eddy detection and tracking method. In this case study, we identify two CFEs referred to as C〈sub〉1〈/sub〉 and C〈sub〉2〈/sub〉 with lifetimes of 11 and 38 days and radii of 45 and 70 km, respectively, and one anticyclonic eddy (ACE) with a lifetime of 62 days and a radius of 60 km. Both CFEs interact with the ACE leading to quasi-stationary dipole-eddies located in the vicinity of the shelf. This is the first time dipole-eddies are reported for the intensification zone of the EAC. The location of CFEs characterised by negative sea surface height anomaly (SSHA) and clockwise rotation coincides with remotely-sensed sea surface temperature (SST) and chlorophyll-a (Chl-a) anomalies. CFEs C〈sub〉1〈/sub〉 and C〈sub〉2〈/sub〉 appear to contribute in different ways to the cross-shelf transport along the shelf-break. CFE C〈sub〉1〈/sub〉 drives a stronger onshore transport, while CFE C〈sub〉2〈/sub〉 appears to enhance the offshore transport. The estimated export of shelf water associated with CFE C〈sub〉2〈/sub〉 is estimated with about 1.23 Sv (∼106 km〈sup〉3〈/sup〉 day〈sup〉−1〈/sup〉). It renews the regional shelf water in about 7 days. The lifetime of CFE C〈sub〉2〈/sub〉 is about 38 days, thus the eddy had the potential to flush the shelf at least five times. The CFEs intensify the cross-shelf exchange that is due to the wind-driven cyclonic circulation of the Fraser Gyre. This seasonally occurring gyre dominates the local shelf during austral autumn and winter. The results from this study demonstrate the importance of CFEs in exporting cooler and Chl-a enriched shelf water into the warmer and oligotrophic waters of the southward-flowing EAC.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419300307-fx1.jpg" width="293" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Alan L. Shanks〈/p〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Dan Baird, Harald Asmus, Ragnhild Asmus, Sabine Horn, Camille de la Vega〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There is substantial evidence that climate warming affects terrestrial and marine ecosystems. In addition to the geographic shifts of marine species and communities, comprehensive mesocosm experiments provide insight in the behavior of species and simplified ecosystems under climate warming conditions. Food web dynamics and stability has been topical in contemporary ecology, and while these aspects receive considerable attention, few studies have quantitatively examined the impact of climate warming on complex marine ecosystems and their food webs. Here we examine the response of a large marine ecosystem, the Sylt-Rømø Bight in the northern German Wadden Sea, to warmer temperatures by means of ecological network analysis (ENA). Three quantitative network models (of 67 model compartments each) were constructed for each of 4 non-consecutive years (1995, 2007, 2011, 2013). A base-line model at the mean annual ambient temperature, and models at +3 °C and +5 °C above the annual mean were constructed for each year (a total of 12 models) and assessed by ENA protocols. Results showed i.a. an intensification of detrital production and consumption, substantial increase in the total system throughput (TSTP), decline in consumption of phytoplankton and macrophytes, an increase in the total overhead, an increase in community respiration, and an increase in the system's P/B and R/B ratios. The mean relative ascendency declined compared to the base models by 2.35% and 2.28% in the +3 °C and +5 °C networks models respectively. It is clear from the suite of system metrics and ratios that the ecosystem becomes less organized, more dissipative and shifts towards detritus based food webs at higher water temperatures.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Jiaze Wang, Kehui Xu, Samuel J. Bentley, Crawford White, Xukai Zhang, Haoran Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The stratigraphic architecture of Plaquemines sub-delta lobe is identified from sedimentary cores and sub-bottom seismic data collected at Lower Breton Sound, Louisiana, USA. Four lithofacies are identified in cores from bottom to top: (1) organic-poor mud; (2) organic-poor silty sand; (3) massive mud; (4) organic-rich peat and root-rich soft mud. Overall, the lithofacies displays a typical progradational deltaic deposit at bottom with upward-coarsening feature, and then an upward-fining deposit overlying on top. Stratigraphic position of the organic-rich peat facies indicates that it is formed after the fluvial sediment source moves away from this region, and it is recognized as a termination of progradation of the Plaquemines sub-delta. Dated peat samples shows that sub-delta progradation stops between 876 and 1384 yr A.D., during which a 20–70 cm relative sea-level rise is detected. The geological framework reported in this study provides critical information for future modeling on river diversions. The stratigraphic architecture underlying Lower Breton Sound implicates that top three facies of root-rich soft mud, organic-rich peat and massive mud are likely to be eroded away before the development of new crevasse-splay or sub-delta, when sediment diversion is in operation. The deeper organic-poor silty sand lithofacies, however, can serve as a firm foundation to build new land.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 14 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews〈/p〉 〈p〉Author(s): Joydip Mukhopadhyay〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Archean banded iron formations (BIFs) are important lithologies for understanding the early Earth processes. Greenstone belts in the four Archean cratonic nucleii of peninsular India, namely, Singhbhum, Bastar, Dharwar, and Bundelkhand host BIF units that can be important candidates for case studies. The BIFs in these greenstone successions represent both Algoma- and Superior-type associations. The oldest record comes from the Paleoarchean Southern, Eastern and Western Iron Group of the Singhbhum craton and the Sargur supracrustals of the Dharwar craton. Mesoarchean and Neoarchean greenstone belts in the Dharwar and Bundelkhand cratons record a number of cycles of BIF deposition in a spectrum of depositional settings from manganiferous arenite-carbonate shelf associations to deep-water volcanics and graywacke associations. The BIFs from the Neoarchean Bailadila Group in the Bastar craton were deposited in siliciclastic shelf association. Compositional variations in major, trace and REE patterns have been evaluated from published data. High-grade iron ores are mainly mined from the BIFs and locally Mn-ores occur in association as well. Microbial carbonates associated with some of the Paleoarchean as well as Neoarchean iron-manganese formations suggest early life activities. The lithological association of the Archean iron formations have been explained in terms of both active margin and passive margin depositional settings. BIFs in association with manganiferous formations as old as Paleoarchean time provide an opportunity to probe into the redox stratification of oceanic hydrosphere and in turn the oxygenation of early atmosphere.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): V. Venekey, T.P.G. Melo, J.S. Rosa-Filho〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the Amazonian coast seasonal changes of environmental characteristics are the main structuring factors of coastal benthic communities. Spatial and temporal variations in meiofauna and nematofauna were studied during rainy and dry seasons in the coastal zone of the Biological Reserve of Piratuba Lake (Bazil Amazonian coast). At each site (seven sites) five samples were taken in vegetated (inside the mangrove – 100 m from the border) and non-vegetated (outside of the mangrove – 100 m from the border) areas. Each sample was sliced in 0–2 cm, 2–5 cm and 5–10 cm deep layers. Water surface temperature and salinity were determined. Meiofauna was composed of 15 taxa: Nematoda, Copepoda, Ostracoda, Amphipoda, Cladocera, Isopoda, Acari, Polychaeta, Gastropoda, Turbellaria, Rotifera, Loricifera, Nemertea, Kinorhyncha, and Insect larvae. Nematoda (39 genera in 14 families) was the dominant group, accounting for 70% of the total individuals. 〈em〉Daptonema, Neochromadora, Hypodondolaimus〈/em〉, and 〈em〉Dichromadora〈/em〉 were dominant. Only salinity significantly changed between seasons and was significantly higher in the dry season. Meiofauna and nematofauna density and richness were lower than those in other mangroves worldwide. The significant changes in meiofauna and nematofauna between seasons and depths were related to higher salinity and food availability during the dry season and more food and oxygen available close to the surface (0–2 cm depth). Meiofauna did not show significant differences between vegetated and non-vegetated areas; however, higher density and richness were generally recorded in the vegetated areas, where food is more abundant, and the substrate is more stable. Non-selective deposit-feeding nematodes were dominant in all areas, seasons and depths. During the rainy season, the second most abundant feeding group was predators/omnivores as a response to an increase in organic detritus, whereas epigrowth feeders were the second most abundant group during dry season due to increased phytoplankton and phytobenthic production.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771417311873-fx1.jpg" width="364" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Karina Hartmann, Martin Stock〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Clay-rich salt marshes of mesotidal Wadden Sea coasts and of estuaries have been established mainly within artificial sedimentation fields in front of embankments. Natural salt marsh formation and natural range expansion outside artificial structures were rare. In the last three decades of this century natural marshes along the southern Wadden Sea coast of Schleswig-Holstein, Germany, started to grow outside groyne fields and extended on tidal mudflats. This growth happened without direct human influence and naturally structured marshes of considerable spatial dimension evolved.〈/p〉 〈p〉Due to a spread in recent decades, natural grown marshes in our study area – southern Schleswig-Holstein Wadden Sea coast - are younger than man-made marshes. Vegetation developed rapidly in response to fine-scaled geomorphological conditions. Meandering creeks and different surface elevation ranges of the developing natural salt marsh are special features. The naturally grown marshes show a high proportion of pioneer vegetation with 〈em〉Spartina anglica〈/em〉 and 〈em〉Salicornia europaea〈/em〉. Succession proceeds fast and elevated parts of the marsh were rapidly colonised with marsh vegetation of 〈em〉Puccinellia maritima〈/em〉 and 〈em〉Aster tripolium〈/em〉 in the lower marsh to late successional stages, like 〈em〉Halimione portulacoides〈/em〉 and 〈em〉Elymus athericus〈/em〉, on the higher elevated parts. Strikingly, median elevations of the vegetation zones in the natural marsh were several centimetres lower than those of the man-made marsh. The largest difference between both marsh types was the characteristic and the extent of drainage systems. Naturally grown marshes have a natural developed, fine-branched and four times shorter drainage system than man-made marshes with a dense drainage structure.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Troy A. Rogers, Anthony J. Fowler, Michael A. Steer, Bronwyn M. Gillanders〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Connectivity during the ontogenetic development of fishes identifies the spatial scale over which populations function, and the appropriate scale for conservation and management. For many marine species, spawning grounds and nursery areas are spatially segregated and larval dispersal is an obligate process that connects life history stages. This study investigated the spatial scale of early life history for one such species, the King George whiting (〈em〉Sillaginodes punctatus〈/em〉; Perciformes), through the retrospective analysis of otolith microstructure and elemental chemistry of recently-settled larvae. The aim was to determine whether the South Australian population constitutes a single panmictic stock, or if it comprises multiple sub-populations. Sizes (15.1–25.1 mm SL), ages (85–183 d) and hatch dates (24-Apr to 1-Aug) of larvae varied considerably between nursery areas at different spatial scales. Regional differences in multi-elemental otolith signatures indicated that multiple spawning grounds contribute to recruitment, and larvae that settled in each region dispersed through different water masses. Within each region, there were differences in hatch dates and otolith chemistry indicative of finer-scale relationships between particular spawning grounds and nursery areas, consistent with local oceanographic circulation patterns. Although multi-elemental signatures were year-specific, concentrations of Ba and Mn were largely responsible for spatial differences and assigned larvae to regional groups with 52–66% accuracy. The results suggest the State-wide stock is replenished by three putative source populations, and provide an example of how otolith chemistry can discriminate among geographically-close, yet-ecologically separated groups of fish in coastal marine ecosystems.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419305062-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 12 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): H.E. Woo, T.V. Tran, I.C. Lee, J.O. Kim, Tadashi Hibino, Hideaki Nohara, K.H. Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Widespread pollutants from wastewater are serious threats to the ecosystem and aquatic environments in harbor areas. However, very few methods are available for the remediation of contaminated sediments. Herein we examine an 〈em〉in-situ〈/em〉 method using a new material, known as slaked lime–fly ash–cement mixture (SFCM), that removes phosphate and hydrogen sulfide from contaminated sediments. For this purpose, we analyze the effects of SFCM based on mesocosm experiments. After the application of SFCM, the hydrogen sulfide concentration significantly decreased from 130 to nearly 0 mg L〈sup〉−1〈/sup〉 and remained at this level for nearly six months. The phosphate concentration in the sediment decreased to its lowest level at 5 mg L〈sup〉−1〈/sup〉 and decreased for the remainder of the experimental period. These results demonstrate the successful removal of phosphate and hydrogen sulfide by applying SFCM. Results also showed that the pH remained between 8 and 8.2 after experimentation, which is similar to seawater pH. Based on these results, we conclude that SFCM is an effective material to mitigate contaminated coastal sediment in harbor areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 12 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Qingqiang Ren, Weiwei Xian, Chunlong Liu, Wenlong Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Identifying drivers of coastal nektonic invertebrate community structure requires detailed analyses of species assemblage composition and environmental variables. We analyze biological and environmental data collected over five spring seasons from 2013 to 2017 from waters in and adjacent to the Yangtze Estuary. Of 31 species, crustaceans were dominant in abundance and biomass. Abundance and biomass had different spatial distribution characteristics among years. The Taiwan Warm Current, low in dissolved oxygen (DO) and high in temperature (T), encroached into the East China Sea from Taiwan Strait, contributing to hypoxic conditions and warm waters. Yangtze River flows contributed to low estuarine salinity (S). Canonical correlation analysis (CCA) and analysis of similarities (ANOSIM) identified that nektonic invertebrate community structure fluctuated among five years and had significant spatial variation, of which communities of 2013, 2014 and 2015 differed significantly from all other years and no significant difference was apparent between that of 2016 and 2017, and two distinct assemblages were stratified by depth (D). Nekton abundance and biomass were highest in 2014, and varied significantly over time. D, DO, T and S were key factors structuring the nektonic invertebrate community. D significantly affected the spatial distribution of communities, while T significantly affected temporal variation. Hypoxic zones were associated with low abundance and biomass, indicating DO also strongly influenced community structure and species growth.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 8 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Annelore bezzi, Giulia Casagrande, Davide Martinucci, Simone Pillon, Carlo Del Grande, Giorgio Fontolan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Barriers and spits connected to fluvial sedimentary sources represent environments which tend to evolve rapidly and experience sudden transformations, mainly driven by changes in sediment supply and path. As a consequence, the variability of facies is significant even within small sedimentary records. The 7 km long barrier-spit system facing the Goro Lagoon, and fed by the mouth of the Po di Goro, is a typical example of an accretionary coastal morphotype, suitable to describe contiguous nearshore depositional environments and their stratigraphic signatures, variability, and relationships. Thirteen short cores of sediment were sampled in order to represent the variable depositional sub-environments from the shoreface (prodelta-delta front) to the back barrier, crossing the active barrier-spit and the ancient spit arms and relative swales. The description of the modern sedimentary records, improved upon using core X-rays, has been coupled with information on the morphological changes which occurred during the period of maximum spit development (1955–2000), based on available aerial photos and a cartographic/topographic dataset. The results obtained allow for the description and interpretation of the depositional environments changing at the human-scale. Sediments of the upper shoreface are quite uniform, composed by evenly laminated sands; the transition between delta front and prodelta at a depth of 6 m is marked by the alternation of sand and mud beds. These reflect the periodic changes in sediment supply by the river, as well as storm events. The most recent spit branch and the relative back barrier-swale environment are the result of the rapid progradation of the spit system, which implies phases of rapid longshore growth, hooked spit development, cannibalization, overwash, and breaching. Morphodynamic changes have resulted in an overlap of short sedimentary records where stratigraphic signatures are linked either to phases of sediment transport and selection by waves and tidal currents (cross-bedding, foreset and planar laminated sands, shell imbrication, massive beds) or to phases of sedimentary stasis when biological activity is predominant (algal mat and bioturbation). Human signature is also well marked inside the stratigraphic record. Clam harvesting is carried out within the lagoon causing the physical disturbance and winnowing of the superficial sediment, thus inducing the local formation of graded beds and shell rehash.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Jonathan D. Phillips, Łukasz Pawlik, Pavel Šamonil〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A distinct boundary between unweathered and weathered rock that moves downward as weathering proceeds—the weathering front—is explicitly or implicitly part of landscape evolution concepts of etchplanation, triple planation, dynamic denudation, and weathering- and supply-limited landscapes. Weathering fronts also figure prominently in many models of soil, hillslope, and landscape evolution, and mass movements. Clear transitions from weathered to unweathered material, increasing alteration from underlying bedrock to the surface, and lateral continuity of weathering fronts are ideal or benchmark conditions. Weathered to unweathered transitions are often gradual, and weathering fronts may be geometrically complex. Some weathering profiles contain pockets of unweathered rock, and highly modified and unmodified parent material at similar depths in close proximity. They also reflect mass fluxes that are more varied than downward-percolating water and slope-parallel surface processes. Fluxes may also be upward, or lateral along lithological boundaries, structural features, and textural or weathering-related boundaries. Fluxes associated with roots, root channels, and faunal burrows may potentially occur in any direction. Just as pedology has broadened its traditional emphasis on top-down processes to incorporate various lateral fluxes, studies of weathering profiles are increasingly recognizing and incorporating multidirectional mass fluxes. Examples from karst systems may also be useful, where concepts of laterally continuous weathering fronts, rock-regolith boundaries, and water tables; and an assumption of dominantly diffuse downward percolation are generally inapplicable. We also question the idea of a single weathering front, and of a two-stage process of weathering rock to regolith, and transforming regolith to soil. In many cases there appears to be three stages involving conversion of bedrock to weathered rock, weathered rock to regolith, and regolith to soil.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Nasreen Peer, Nelson AF. Miranda, Renzo Perissinotto〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Microphytobenthos (MPB) are important primary producers in mangroves, where they are an important source of food for fiddler crabs. The St Lucia mangroves are currently disconnected from the sea and thus considered a non-tidal mangrove ecosystem. Fiddler crabs occur close by, along with sympatric sesarmid crabs. This study examined the foraging effects of the fiddler crab 〈em〉Austruca occidentalis〈/em〉 on MPB biomass and composition. The effects of two dominant sesarmids, 〈em〉Chiromantes eulimene〈/em〉 and 〈em〉Neosarmatium africanum〈/em〉, on 〈em〉A. occidentalis〈/em〉 were also investigated as sesarmids are known to interfere with fiddler crab surface activities such as foraging and burrow maintenance.〈/p〉 〈p〉〈em〉In situ〈/em〉 experimental plots contained fiddler crabs at three different densities, combinations of fiddler crabs and sesarmids, and controls with no crabs. The biomass of three main microalgal groups were measured (i.e. diatoms, cyanobacteria and green algae) using a fluoroprobe and overall MPB biomass was measured using acetone extraction analysis.〈/p〉 〈p〉〈em〉Austruca occidentalis〈/em〉 affected cyanobacteria and diatoms, allowing green algae to increase in biomass during the experimental period. The presence of sesarmids was shown to affect cyanobacteria biomass more than either of the other two algal groups. Overall, MPB biomass was unaffected by fiddler crab density or sesarmid presence, suggesting that abiotic factors played a more important role in controlling biomass while biotic grazing and interference only affected microalgal group composition.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419306006-fx1.jpg" width="367" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Dongxue Li, Zhiqiang Gao, Debin Song, Weitao Shang, Xiaopeng Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Green tides in the Yellow Sea have occurred in large-scale blooms since 2007. Originating in the southern Yellow Sea and drifting northward continuously, these green tides have severely affected the coastal ecological environment. To analyze the influence of green tides on marine aquaculture in the Rongcheng coastal water (the northernmost sea area influenced by green tide), we used the Moderate Resolution Imaging Spectrometer (MODIS), GaoFen-1 (GF-1) satellite imagery and the sea surface wind (SSW) data. We also used field investigation to analyze the drift trajectory, drift speed, dissipation speed and distribution density of green tides. The results show that the main body of a green tide will drift northeast and continue in this direction after crossing the Rongcheng Chengshanjiao coastal water. Between 2013 and 2018, the drift speeds of green tides to the north of this area were within 1–5 km/d, the drift speed in the east-west direction was 0.3–4 km/d, and the interannual difference was not significant. The dissipation speed of the green tide in the Rongcheng Sea is generally within the range of 1–5 km〈sup〉2〈/sup〉/d and shows little interannual difference. The distribution density in the southern area of Rongcheng is the highest, ranging from 3% to 7%. The area with the highest frequency of influence is also the area with the greatest distribution density of green tides, and disasters are most severe here. A reasonable collection area is proposed, based on the above analysis. This research provides the basis for understanding the characteristics of green tides in the dissipation phase, and the prevention and control methods of green tide disasters in the Rongcheng coastal water.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Xia Hua, Huiming Huang, Yigang Wang, Yinyu Lan, Kun Zhao, Dake Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrodynamics and the estuarine turbidity maximum (ETM) were investigated along the Deepwater Navigation Channel (DNC) in the North Passage (NP) of the Changjiang River Estuary (CRE) during spring tides in March (dry season) and July (wet season) in 2016. The along-channel water current, salinity, and suspended sediment concentration (SSC) were measured and compared with a study undertaken in 2012. Results show that the magnitude of SSC in the dry season was significantly larger than that in the wet season in 2016, which was contrary to the results obtained in 2012 and the commonly held understanding that SSC is much higher in wet seasons than dry seasons in this region. Despite the abnormal magnitude of the SSC, the spatial distribution agreed with that of the 2012 observations, and corresponded to the salinity distribution. By analysing the bottom sediment flux and sediment transport over a flood-ebb tidal cycle, the immediate cause of the abnormal SSC magnitudes was found. In the dry season, the resuspension fluxes were more than doubled and tidal pumping terms were significantly larger than of those in the wet season, thus indicating that the resuspension effect was much stronger and able to bring more sediment into the water. Although the strong resuspension effect in the dry season was partly due to a slightly higher tidal dynamic, it was mainly due to the availability of sufficient sediment for resuspension, as induced by the strong cold-air front several days previous. On the contrary, the weak resuspension effect under a similar tidal dynamic in the wet season, was associated with insufficient sediment availability as a result of the limited influence of the typhoon in 2016. In addition, the quantity of sediments available for resuspension influenced the mobile suspension (MS) events of the ETM. Local resuspension and along-channel advection were both important in SSC variation processes and the effect of along-channel advection was more distinct when there was insufficient sediments for resuspension.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 198〈/p〉 〈p〉Author(s): Zsuzsa Lisztes-Szabó〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Phytoliths (silica bodies in plants) are used as proxies in paleoecological and archaeological studies because of their taxonomical relevance and persistence in soils and sediments after the degradation of the plant. In the recent review of Rashid et al. (2019), which summarized the literature of phytolith research, Figure 2 presented an inaccurate description of the anatomical structure of a rice plant in connection with creating phytoliths in the plants. It is essential to correct the errors of this imprecise illustration.〈/p〉 〈p〉Complex environmental research needs to rely on different scientific fields, including plant anatomy. We have to take into account that the inaccurate descriptions as well as knowledge of the anatomical structure of the plants may result in incorrect conclusions with respect to physiological processes of creating phytoliths and evaluating the effects of environmental factors on them.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Inês Leal, Augusto A.V. Flores, Rachel Collin, Réjean Tremblay〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Settlement of most marine benthic invertebrates is intrinsically linked to the end of the pelagic life, but for a few, the transition to the benthos can be less well-defined. Early metamorphosed postlarvae of temperate and subtropical bivalves are known to delay final settlement, i.e., undergo secondary migrations, until detecting specific habitat cues. Here, we test the hypothesis that postlarval drifting occurs as well in tropical systems, being mediated by the nutritional quality of nearshore waters. We monitored early stages of the flat tree oyster 〈em〉Isognomon alatus〈/em〉 on the Caribbean coast of Panama, and observed successive numerical dominance of late-stage larvae (pediveligers) and postlarvae (juvenile drifters) of this isognomonid in the water column. Of all the pelagic individuals collected, 19% corresponded to juvenile drifters, suggesting that conditions favoring juvenile drifting were present at the time of sampling and/or juvenile drifting may be commonplace for this species. During 23 consecutive sampling days, we detected a single settlement peak of long-term drifters that followed a decrease in sea-surface salinity. The shell morphology of juveniles revealed that first settlement for 〈em〉I. alatus〈/em〉 takes place after theoretical competence, when prodissoconch II exceeds c. a. 300 μm. A shift in nearshore trophic conditions was detected after settlement, with particulate matter dominated by tracers of microalgae and vascular plant matter shifting to tracers for detritic matter and bacterial load. Essential fatty acids comprised 28% of the seston, yet, were minimally accumulated by 〈em〉I. alatus〈/em〉 pediveligers (2% of energetic reserves). We highlight the importance of accounting for juvenile drifters of 〈em〉I. alatus〈/em〉 on settlement estimates, as the spatial distribution of late larval stages and/or early settlers might not reflect their final distribution. This information is key to manage, exploit and/or conserve natural stocks.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771419305281-fx1.jpg" width="449" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Elisa Baldrighi, Jacques Grall, Nolwenn Quillien, Rita Carriço, Valentin Verdon, Daniela Zeppilli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Open sandy beaches support key ecological functions and a distinctive biodiversity, but are threatened by an increasing anthropogenic pressure. Among these threats is the occurrence of green tides of 〈em〉Ulva〈/em〉 spp., expression of the eutrophication phenomenon. Our study aimed at determining the impact of green macroalgal accumulations on benthic meiofauna inhabiting two macrotidal sandy beaches of Brittany: Saint Nic (impacted) and Anse de Dinan (unimpacted). The presence of 〈em〉Ulva〈/em〉 enhanced total meiofaunal abundance and nematode functional diversity when compared to a state free from macroalgal mats. The stranded 〈em〉Ulva〈/em〉 supported high values of meiofaunal β-diversity as well. This unexpected response was likely due to the highly dynamic nature of open sandy beaches that prevents O〈sub〉2〈/sub〉 depletion within sediments. Natural seasonal changes in meiofaunal biomass and composition were also evident at both beaches and changes in environmental features, apart from eutrophication alone, do drive the variability in meiofaunal biomass and nematodes diversity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Tuyet T.N. Nguyen, Julien Némery, Nicolas Gratiot, Josette Garnier, Emilie Strady, Viet Q. Tran, An T. Nguyen, Thi N.T. Nguyen, Claire Golliet, Joanne Aimé〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Saigon River flows through one of the most rapidly growing megacities of Southeast Asia, Ho Chi Minh City (HCMC, 〉 8.4 million inhabitants). This tidal river is characterized by a tropical monsoon climate, alternating a wet and a dry season. In the last few decades, increased economic and urban developments of HCMC have led to harmful impacts on the water quality of this tidal river, with severe eutrophication events. This situation results from the conjunction of contrasting hydrological seasons and the lack of upgraded sanitation infrastructures: indeed, less than 10% of the domestic wastewater is collected and treated before being discharged directly into urban canals or rivers. This study focuses on P dynamics because this is considered the key nutrient factor controlling freshwater eutrophication. Based on field measurements and original laboratory experiments, we assessed the P levels in the river water and sediments, and investigated P adsorption/desorption capacity onto suspended sediment (SS) within the salinity gradient observed. Field surveys showed a clear impact of the HCMC megacity on the total P content in SS, which increased threefold at HCMC Center, as compared with the upstream values (0.3–0.8 gP kg〈sup〉−1〈/sup〉). Downstream, in the mixed estuarine area, the Total P was lower than 0.5 gP kg〈sup〉−1〈/sup〉. Laboratory experiments were carried out to characterize the influence of SS concentrations (SS = [0.25–0.9] g L〈sup〉−1〈/sup〉), salinity (S = [2.6–9.3]) and turbulence (G = [22–44] s〈sup〉−1〈/sup〉) on the sorption capacity of P onto sediment. The size of sediment particles and their propensity to flocculate were also originally measured with a recently developed instrument: the System for the Characterization of Aggregates and Flocs (SCAF®). Under the experimental conditions considered, SS concentrations had the greatest effect on the adsorption of P onto sediment, e.g., P adsorption capacity increased when SS concentrations rose. In contrast, salinity and turbulence had a smaller effect on the adsorption properties of sediments. Among these observed variables, the SS concentration was shown to be the main driver for adsorption capacity of P onto SS within the salinity gradient. We discuss the implication of these findings on understanding P dynamics within a highly urbanized, tropical estuary.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science, Volume 217〈/p〉 〈p〉Author(s): Chao Chen, Jiaoqi Fu, Shuai Zhang, Xin Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a dynamic belt between land and oceans, coastline provides rich information on land-ocean interactions. Sensitive to climate and anthropogenic influences, the changing coastline affects intertidal mudflat resources and the coastal environment. In this study, the greenness and wetness components of the tasseled cap transformation (TCT) were used to extract coastline information. Due to the high total suspended sediment content that leads to the failure of traditional method, sea-waterbody information extraction was initially carried out by TCT. After considering the characteristics of coastline in remote sensing images and coastline morphology in the natural world, the coastline with shorter length was eliminated and the intermittent coastline was connected based on the coordinate geometry description (such as length, distance, and direction). Finally, the results of the coastline information extraction were superimposed on the original images to evaluate accuracy. The experimental results indicated that the proposed method was more effective in clearly delineating the land-ocean boundary. The producer's accuracy and user's accuracy were 0.95 and 0.91, respectively, and the length extraction error was −2.16%. Therefore, the proposed method was more successful for coastline information extraction in the area with high sediment concentration.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews〈/p〉 〈p〉Author(s): Jack Longman, Martin R. Palmer, Thomas M. Gernon, Hayley R. Manners〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Preservation of organic carbon (C〈sub〉org〈/sub〉) in marine sediments plays a major role in defining ocean-atmosphere CO〈sub〉2〈/sub〉 levels, Earth climate, and the generation of hydrocarbons. Important controls over sedimentary C〈sub〉org〈/sub〉 preservation include; biological productivity, C〈sub〉org〈/sub〉 isolation from oxidants (mainly dissolved O〈sub〉2〈/sub〉) in the overlying water column and sediments, and C〈sub〉org〈/sub〉 – mineral association in sediments. Deposition of the products of explosive volcanism (tephra) in the oceans directly enhances C〈sub〉org〈/sub〉 burial through all these mechanisms, and indirectly through enhanced formation of authigenic carbonate (C〈sub〉auth〈/sub〉) derived from sedimentary C〈sub〉org〈/sub〉. In the modern oceans, it is suggested that tephra deposition may account for 5–10% of the C〈sub〉org〈/sub〉 burial flux and 10–40% of the C〈sub〉auth〈/sub〉 burial flux. However, during certain periods in Earth's history, extensive explosive volcanism may have led to enhanced C〈sub〉auth〈/sub〉 precipitation on a sufficiently large scale to influence the global ocean-atmosphere carbon cycle. Changes in tephra-related C〈sub〉org〈/sub〉 preservation may also have played a role in increasing C〈sub〉org〈/sub〉 preservation rates in local marine basins, at the oxic-anoxic boundary and enhanced the generation of hydrocarbon deposits in these settings.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 26 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): M.Siobhan Fennessy, Carles Ibáñez, Juan Calvo-Cubero, Peter Sharpe, Albert Rovira, John Callaway, Nuno Caiola〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Delta wetlands are increasingly recognized as important sinks for ‘blue carbon,’ although this and other ecosystem services that deltas provide are threatened by human activities. We investigated factors that affect sediment accretion using short term (3 years using marker horizons) and longer-term measures (∼50 year using 〈sup〉137〈/sup〉Cs soil core distribution and ∼100 year using 〈sup〉210〈/sup〉Pb distribution), the associated carbon accumulation rates, and resulting changes in surface elevation in the Ebro River Delta, Catalonia, Spain. Fifteen sites were selected, representing the geomorphological settings and range of salinities typical of the delta's wetlands. Sediment accretion rates as measured by 〈sup〉137〈/sup〉Cs distribution in soil cores ranged from 0.13 to 0.93 cm yr〈sup〉−1〈/sup〉. Surface elevations increased at all sites, from 0.10 to 2.13 cm yr〈sup〉−1〈/sup〉 with the greatest increases in natural impoundments with little connection to other surface waters. Carbon accumulation rates were highly spatially variable, ranging from 32 to 435 g C m〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉 with significantly higher rates at bay sites (p = 0.02) where hydrologic connectivity is high and sediment resuspension more intense. Sites with high connectivity had significantly higher rates of carbon accumulation (averaging 376 ± 50 g C m〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉) compared to sites with moderate or low connectivity. We also found high rates of carbon accumulation in brackish sites where connectivity was low and biomass production was characteristically higher than in saline sites. A stepwise regression model explained 81% of variability in carbon accumulation rates across all sites. Our data indicate deltaic wetlands can be important sinks for blue carbon, contributing to climate change mitigation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science, Volume 220〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Gabriel Pereira Frota, Tatiana M.B. Cabrini, Ricardo S. Cardoso〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sandy beaches are the most frequented coastal environments in the world, and they consequently suffer different types of impacts due to the rapid urban occupation and demographic growth in coastal regions, which generate stressful conditions for the resident species and reduce the environmental quality of the beaches for resident species. Crustaceans can be used as reliable bioindicators of human stress, and the amphipod 〈em〉Atlantorchestoidea brasiliensis〈/em〉 and the decapod 〈em〉Emerita brasiliensis〈/em〉 are highlighted. One tool for evaluating the environmental quality and the instability of individual development is fluctuating asymmetry (FA), which measures small, random deviations from a perfect bilateral symmetry. To evaluate the environmental quality of the beaches, some indices have been developed in recent years; among the most used are the conservation, recreation and urbanization indices, which offer easy-to-use metric for decision makers. This study aimed to quantify and compare the levels of FA in the populations of 〈em〉A. brasiliensis〈/em〉 and 〈em〉E. brasiliensis〈/em〉 on 14 beaches in Rio de Janeiro State with different levels of urbanization and conservation. For each species, two individual indices and two composite indices of asymmetry were calculated and tested in four bilateral traits. The urbanization, recreation and conservation indices were used to assess environmental quality of the sandy beaches. The results of the present study indicate a complex spatial distribution of FA in relation to the indices of the environmental quality of the beaches. The beaches that obtained the highest values in the conservation index obtained the lowest values of FA for both species. The beaches located in the Metropolitan region, specifically in the city of Rio de Janeiro, generally presented the highest levels of FA for both species. These species are susceptible to different forms of impacts due to their distinct characteristics in feeding behavior, development mode and beach zone occurrence. 〈em〉A. brasiliensis〈/em〉 is more susceptible to direct impacts on the beach, such as recreational activities, while 〈em〉E. brasiliensis〈/em〉 is more sensitive to impacts on water (contamination and physicochemical changes). Our results indicate that fluctuating asymmetry can be used as a good tool to evaluate impacts on sandy beaches, but additional studies should be conducted to improve the understanding of the spatial distribution of FA on sandy beaches.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771418308035-fx1.jpg" width="270" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Chilwoo Lee, Sooncheol Hwang, Kideok Do, Sangyoung Son〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Unlike inundation from a tsunami, inundation originating from a tropical cyclone is rather complex since it is usually accompanied by torrential rain. Runoff in the vicinity of an estuarine outlet may thus incur additional inundation damage. In this study, a modeling system is proposed that considers the river discharge effect in addition to tides and surges to enhance the modeling accuracy of storm-induced inundation in coastal areas. The hydrodynamic model (Delft3D) and hydrological model (HEC-HMS) were coupled to account for all the flooding drivers, such as tides, storm surges, river discharges, and their interactions. In the coupled model, Delft3D was responsible for tidal and storm-induced surging motions, while HEC-HMS was used to calculate the river discharge at the downstream outlet of basins. Typhoon Maemi, which caused severe inundation damage to the Korean peninsula in 2003, was simulated by the model with a focus on the localized inundation process. The increase in inundation risk caused by river discharge was of particular interest and was assessed through a comparison of two different cases: Case ST (Storm-Tide) and Case STR (Storm-Tide-Riverine flow). The results clearly show that the case considering the rainfall-runoff process in the storm surge simulation outperforms that in which storm surge is not considered. A further detailed investigation of the inundation depth and coverage of both cases revealed several findings. The proposed model is expected to be of great aid in producing the flood hazard mapping with enhanced accuracy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 26 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Justas Dainys, Eglė Jakubavičiūtė, Harry Gorfine, Žilvinas Pūtys, Tomas Virbickas, Darius Jakimavičius, Diana Šarauskienė, Diana Meilutytė-Lukauskienė, Arvydas Povilaitis, Arūnas Bukantis, Justas Kažys, Linas Ložys〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climate change is likely to increasingly impact estuarine fish populations. Changes in water temperature or salinity can have deleterious effects on fish growth and behaviour. A decrease in the abundance of freshwater fish in the northern areas of the Curonian Lagoon has been attributed to increased salinity of inflowing water from the Baltic Sea. Thus, this study investigated the effects of possible changes in environmental salinity and temperature on the growth and behaviour of perch (〈em〉Perca fluviatilis〈/em〉 L.). Laboratory experiments revealed that brackish water (salinity 3 and 6) has neither a negative nor a positive effect on growth rates among perch young-of-the-year, when compared to freshwater (salinity 0). In contrast, results from behavioural experiments demonstrated that perch prefer to remain in brackish water (salinity 6) when given a choice between brackish and freshwater, and in warm water (18 °C) when given a choice between warm and cold water (12 °C). For this reason, the temperature rather than the salinity of inflowing colder brackish water from the Baltic Sea will be the most likely driver of short-term changes in fish distribution in the Curonian Lagoon.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Diane Espel, Noël J. Diepens, Olivier Boutron, Evelyne Buffan-Dubau, Yves Cherain, Eric Coulet, Patrick Grillas, Anne Probst, Jerome Silvestre, Arnaud Elger〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Seagrass decline due to a variety of stressors has been observed worldwide. In the shallow Vaccarès lagoon, Camargue, France, the dominant macrophyte species, 〈em〉Zostera noltei〈/em〉, has suffered two major declines since 1996. The first decline was well explained by salinity and turbidity variations, while the second one could not be explained by these parameters. Other stressors such as chemical contamination, eutrophication or temperature increase could be explanatory variables for this most recent decline. The aim of our study was to understand, 〈em〉via〈/em〉 scientific monitoring from 2011 to 2015, the influence of chemical contamination and its possible interactions with other biological and environmental pressures, on seagrass physiology and population dynamics in the Vaccarès lagoon.〈/p〉 〈p〉Multi-contamination by organic contaminants and trace metals was detected in the water and sediments, and their concentrations often exceeded environmental standards, particularly where seagrass regression was observed. Spatial variations in biological, environmental and chemical parameters in the lagoon were investigated by co-inertia analysis, which revealed significant relationships between environmental data, more particularly between contaminants, seagrass dynamics indices and biomarkers. Seagrass dynamics indices were negatively correlated with the concentrations of some herbicides in water (2,4-MCPA and bentazon) and with trace metals in sediments (arsenic). Rhizome starch contents in winter were negatively correlated with those herbicides and with several metals (arsenic, zinc, copper) in water and/or sediments. These results suggest that environmental contamination may play a role in seagrass decline. However, complementary investigations, such as monitoring over longer periods and additional toxicity tests, are required to address the causal link between contamination and seagrass decline.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Weiqing Meng, Rusty A. Feagin, Beibei Hu, Mengxuan He, Hongyuan Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Coastal wetland losses in China are globally-relevant issues, as formerly sequestered soil organic carbon is released as CO〈sub〉2〈/sub〉 into the atmosphere. Wetland losses also reduce the primary production by plants that would otherwise bury carbon in the future. More than 50% of these ecosystems have been lost globally over the last half century, with this number approaching 58% in China. The negotiation of international accords such as the Paris Climate Agreement rely on the accurate assessment of ecosystem-held carbon quantities. Our objective was to provide the first national scale survey of coastal wetland-based carbon in China. The average soil organic carbon stock (Mg SOC ha〈sup〉−1〈/sup〉) across all three types of ecosystems was 236.91, with an average of 344.67 for mangroves, 175.14 for seagrass, and 134.37 for salt marshes. The SOC stock was greatest at 30–60 cm of depth in the case of mangroves, as opposed to 0–20 cm of depth for salt marshes. In terms of the carbon content of the standing aboveground and belowground biomass (Mg C ha〈sup〉−1〈/sup〉), mangroves contained by far the most with an average of 253.98 and 83.96, respectively. Carbon burial rates, or the annual flux of SOC into the soil column (Mg C ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉), were 2.26 ± 0.39 for mangroves, 1.38 ± 0.38 for seagrass, and 2.18 ± 0.24 for salt marshes. Through our work, we found a total of 48.12–123.95 Tg of C in China's coastal wetlands (down to 1 m of soil column depth), with an annual burial of 0.84 Tg yr〈sup〉−1〈/sup〉. We estimate the average annual emissions of CO〈sub〉2〈/sub〉 to be on the order of 6.83 Tg CO〈sub〉2〈/sub〉 yr〈sup〉−1〈/sup〉, due to ongoing and extensive wetland loss and conversion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Eva García-Seoane, Vítor Marques, Alexandra Silva, Maria Manuel Angélico〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study analyzed the spatial and temporal variation in the community composition of the pelagic species inhabiting the Atlantic Iberian waters using a multivariate approach. Trawl data (pelagic and bottom fishing) were collected during the spring acoustic surveys of pelagic fish from 1996 to 2015. There were significant effects of geographical area, periods, and type of trawls in terms of both, abundance and biomass. Sardine was typical throughout the study area whereas other species were typical of few areas, such as anchovy. The main difference between periods was the variation in typical pelagic species, diminishing the importance of sardine and increasing others, such as chub mackerel, bogue or anchovy. Depth also influenced the community structure with horse mackerel being principally responsible for sample similarity in bottom trawls. Surface temperature and salinity showed significant relationship with the taxa-derived multivariate data cloud but only explained between 5 and 7% of the total variability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Edwin J. Bomer, Samuel J. Bentley, Frances Crawford, Joseph E.T. Hughes, Carol A. Wilson, Kehui Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉River-sediment diversions have been recognized as a key strategy for offsetting land loss in coastal Louisiana. Recently, much attention has been focused on sediment capture from the main stem river and conveyance of that material through diversion outflows. Yet, the performance and long-term feasibility of diversions as land-building agents also hinges upon the subsurface stratigraphic architecture of receiving basins, a concept that has largely been unexplored. A major core collection and analysis program was undertaken to study the geological properties of substrates in the Middle Barataria Bay and Middle Breton Sound diversion receiving basins, Louisiana, USA. Over a region of ∼200 square kilometers in both basins, 50 vibracores up to 5.5 m in length were collected in spring and summer of 2015. Cores were logged for bulk density and imaged with a Geotek Multi Sensor Core Logger. Split cores were then subsampled for granulometry, organic content, and 〈sup〉14〈/sup〉C dating. Both receiving basins are characterized by 1–2 m of organic-rich surficial strata, underlain by 〉 2 m of mineral-rich sand and silt beds that display a greater bulk density. Additionally, some cores contain deeper peaty strata intercalated within muds and sands. 〈sup〉14〈/sup〉C dates of these buried peats range between 1910 and 3203 calendar years before present demonstrating that relatively old deltaic strata exist at shallow depths. Age comparisons of stratigraphically-similar peat beds from this study and previous delta-lobe chronological models indicate that the St. Bernard lobe prograded eastward at a time-averaged rate of 75 m/yr. From a geotechnical standpoint, the surficial, uncompacted (〈2 m depth, average 1.15 g/cc bulk density) peaty strata in both basins are likely to erode and/or compact under the influence of diversion flows, but deeper consolidated mineral-rich strata (average 1.85 g/cc bulk density) are likely to be more resistant. Hydrodynamic models that predict the erosion associated with river-sediment diversion outflows in this region would benefit from incorporating a two-layer subsurface configuration, with a weaker, peat-like layer overlying a stronger, mineral-rich layer. The results of our study suggest that regions with an abundance of clastic strata at depth should be sought out when planning coastal restoration methods such as river-sediment diversions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): C.L. Osburn, J.N. Atar, T.J. Boyd, M.T. Montgomery〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Estuaries and coastal waters ultimately receive the terrestrial dissolved organic matter (DOM) exported from coastal watersheds, more directly during extreme precipitation events. Recent work suggests DOM's degradation in coastal waters varies with its quality, which also might vary as a function of precipitation, activating contributions from different sources within a watershed. The aim of this study was to determine the extent to which microbial degradation of terrestrial DOM in the Newport River Estuary, eastern North Carolina, was influenced by precipitation events occurring within the preceding seven days from sampling. We hypothesized that DOM stored in forested wetlands (〈em〉e.g.〈/em〉, pocosins and Cypress swamps) that become connected to the main channel of the Newport River during high precipitation events was more labile than DOM flowing into the estuary under low precipitation events. DOM quality was assessed with optical and stable C isotope (δ〈sup〉13〈/sup〉C) measurements, while DOM lability was assessed by measurements of bacterial production (BP) and mineralization of 〈sup〉14〈/sup〉C-labeled phenanthrene (Pmin), a polyaromatic tracer compound. Aromatic content of DOM, assessed by specific ultraviolet absorbance at 254 nm (SUVA〈sub〉254〈/sub〉) was highest in the river with values well over 5.0 L mg C〈sup〉−1〈/sup〉 m〈sup〉−1〈/sup〉, and decreased with salinity. Antecedent precipitation (AP) of at least 100 mm in the seven days prior to sampling resulted in dissolved organic carbon (DOC) concentrations 〉20 mg L〈sup〉−1〈/sup〉, at salinities 〈10. Similarly, fluorescence humification index (HIX) values were highest in the estuary after the highest AP. Generally depleted δ〈sup〉13〈/sup〉C-DOC values (−26 to −28‰) in the estuary up to a salinity of 30 indicated a substantial source of DOM likely originating from the forested swamps and tidal wetlands fringing the estuary. BP exhibited wide variability yet declined with salinity, while median values after higher AP (40 μg C L〈sup〉−1〈/sup〉 d〈sup〉−1〈/sup〉) were double that under lower AP. By contrast, aromatic mineralization (Pmin) rates increased as both DOC and CDOM concentrations, and SUVA〈sub〉254〈/sub〉 and HIX values, declined with salinity. However, Pmin rates were highest after the highest AP for the three events sampled. Results indicate that flooding of coastal wetlands mobilizes a large pool of labile DOM which have a large impact on the carbon cycle in estuaries. By altering the quality, as well as quantity of terrestrial organic matter inputs to estuarine systems, extreme events may also affect utilization of aromatic organics by estuarine microbial assemblages, an intriguing research question worthy of further study.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771418306899-fx1.jpg" width="380" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Arnoldo Valle-Levinson, Carlos A.F. Schettini, Eliane C. Truccolo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Time series of current velocity profiles were obtained at the mouth and head of a Brazilian subtropical estuary, the Araranguá, to study its dry-period response to fortnightly tidal forcing, river pulses and wind forcing. The Araranguá exemplifies a series of river-dominated estuaries along southern Brazil with widths 〈200 m. A special feature of the Araranguá, as it is in dozens of subtropical estuaries in the world, is that depth increases landward. Its lower stretch runs parallel to a wind- and wave-dominated sandbar. Hydrographic data showed highly stratified mid and upper reaches, even during the dry period, and variable stratification in the lower reaches. Moored data were recorded at 7 and 30 km from the mouth during 70 days. Two pulses of moderate river discharge (〉30 m〈sup〉3〈/sup〉/s but 〈200 m〈sup〉3〈/sup〉/s) occurred during the observation span. The estuary responded to these pulses by enhancing estuarine exchange. Discharge 〉200 m〈sup〉3〈/sup〉/s appeared in two other occasions late in the observation period and caused seaward flushing of the entire system. Overall, the estuarine circulation resembled that of a fjord when river discharge was moderate and weaker: an active upper layer driven by river discharge moving over a semi-stagnant lower layer. Strongest subtidal exchange developed ∼2–3 days after neap tides, in contrast to other studies where fortnightly modulation is determined by vertical mixing from tides. In the lower estuary, subtidal flows seemed to result from a combination of vertical mixing, from tides and wind, and from tidal advection. Moreover, the lower estuary was much more sensitive to wind forcing than the upper estuary. The upper estuary responded preferentially to river discharge and tidal forcing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Earth-Science Reviews, Volume 187〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: Available online 14 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science〈/p〉 〈p〉Author(s): Alison C. Enchelmaier, Elizabeth A. Babcock, Neil Hammerschlag〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mangroves provide essential habitat for juvenile fish species. Restoration and monitoring are important conservation tools to ensure the recovery and maintenance of coastal mangrove habitats impacted by humans. In this study, Baited Remote Underwater Video Stations (BRVUS) were used to non-invasively examine the relative abundance and richness of fishes within restored mangrove pools in Biscayne Bay, Florida, 15 years after replanting. The potential influence of several environmental factors on fish abundance and richness within the restored mangrove pools was also evaluated. Limited seine sampling was also conducted to provide a comparison of the current fish assemblage with that of two prior surveys using seine nets. Twenty fish taxa were observed in the current study, consisting of five families, two genera, and thirteen species. Several environmental factors emerged as significant influences on the presence and abundance of different fish taxa, especially individual pools. A comparison of CPUE between current and prior seine studies found an increase in forage fish taxa and a shift from taxa that prefer a range of habitats to mangrove specific taxa, indicating an increased ecological function of these mangroves as fish habitat.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0272771417307473-fx1.jpg" width="499" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science, Volume 217〈/p〉 〈p〉Author(s): Monica Montefalcone, Matteo Vacchi, Renata Archetti, Giandomenico Ardizzone, Patrick Astruch, Carlo Nike Bianchi, Sebastiano Calvo, Alessandro Criscoli, Yolanda Fernández-Torquemada, Filippo Luzzu, Gloria Misson, Carla Morri, Gérard Pergent, Agostino Tomasello, Marco Ferrari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Marine coastal ecosystems are facing structural and functional changes due to the increasing human footprint worldwide, and the assessment of their long-term changes becomes particularly challenging. Measures of change can be done by comparing the observed ecosystem status to a purposely defined reference condition. In this paper, a geospatial modelling approach based on 2D mapping and morphodynamic data was used to predict the natural position of the upper limit (i.e., the landward continuous front) of 〈em〉Posidonia oceanica〈/em〉 seagrass meadows settled on soft bottom. This predictive model, formerly developed at the regional spatial scale, was here applied for the first time at the Mediterranean spatial scale in eight coastal areas of Spain, France, Italy, and Greece showing different coastal morphologies and hydrodynamic characteristics, and affected by a number of natural and/or human local disturbances. The model was effective in measuring the regression (i.e., seaward withdrawal) of the meadow upper limit. In all the meadows investigated the upper limit was regressed, laying deeper than the reference condition, with the proportion of regression ranging from 17.7% to 98.9%. The highest values of regression were found in Spain and in France, and were consistent with the highest levels of fragmentation detected with map analysis and of coastal pressures. This geospatial modelling approach represents an effective tool to define the reference conditions when proper pristine areas or historical data are not available, thus allowing the assessment of long-time changes experienced by seagrass ecosystems due to human impacts.〈/p〉〈/div〉 〈/div〉