How Well Do Restored Intertidal Oyster Reefs Support Key Biogeochemical Properties in a Coastal Lagoon?

The restoration of dead/degraded oyster reefs is increasingly pursued worldwide to reestablish harvestable populations or renew ecosystem services. Evidence suggests that oysters can improve water quality, but less is known about the role of associated benthic sediments in promoting biogeochemical processes, such as nutrient cycling and burial. There is also limited understanding of if, or how long postrestoration, a site functions like a natural reef. This study investigated key biogeochemical properties (e.g., physiochemical properties, nutrient pools, microbial community size and activity) in the sediments of dead reefs; 1-, 4-, and 7-year-old restored reefs; and natural reference reefs of the eastern oyster, Crassostrea virginica, in Mosquito Lagoon (FL, USA). Results indicated that most of the measured biogeochemical properties (dissolved organic carbon (C), NH₄ ⁺, total C, total nitrogen (N), and the activity of major extracellular enzymes involved in C, N, and phosphorus (P) cycling) increased significantly by 1-year postrestoration, relative to dead reefs, and then remained fairly constant as the reefs continued to age. Few differences were observed in biogeochemical properties between restored reefs of any age (1 to 7 years) and natural reference reefs. Variability among reefs of the same treatment category was often correlated with differences in the number of live oysters, reef thickness, and/or the availability of C and N in the sediments. Overall, this study demonstrates the role of live intertidal oyster reefs as biogeochemical hot spots for nutrient cycling and burial and the rapidity (within 1 year) with which biogeochemical properties can be reestablished following successful restoration.     

Metals in Podiform Chromitite of Mantle Section of the Tibetan Ophiolite: What Do We Learn From Them?

<正>Ophiolitic podiform chromitites for a long time have been considered as"cumulates"formed by harzburgitemelt interaction and related melt mixing at the upper part of the suboceanic mantle to the Moho transition zone.Within many existing concepts,which are in a focus of this workshop,there is one suggesting that some portion of chromitites originate from deep mantle,where Cr-spinel     

Watershed Export Events and Ecosystem Responses in the Mission–Aransas National Estuarine Research Reserve, South Texas

While inputs from land are recognized as important resources supporting production in estuaries, the role that storm events play in resource delivery and the response of estuarine systems to pulsed inputs are less well appreciated. Temporal variations in (1) watershed export via the Mission and Aransas rivers and (2) nutrient and organic matter dynamics in Copano Bay were examined in the Mission?CAransas National Estuarine Research Reserve, south Texas. Inorganic nutrient, dissolved organic matter (DOM), and particulate organic matter (POM) concentrations in the rivers varied substantially with discharge, as did carbon and nitrogen stable isotope ratios of POM. Accounting for these variations was critical for calculating robust watershed export estimates. In Copano Bay, soluble reactive phosphorus, POM, and DOM remained elevated for several months following major runoff events, whereas inorganic nitrogen was rapidly depleted. Chlorophyll-a concentrations and POC-??¹³C in Copano Bay showed that increased POM concentrations were linked to enhanced in situ production.     

Advancing beyond May 1971: How Do We Deal with the Possibility of Complicated Dyke Geometries, Long-Lived Lips, and Contrasting Basement Geological Provinces?

正The iconic image of a giant radiating dyke swarm subsequently fragmented into three pieces via supercontinental breakup was produced by Paul May in1971(see next page).That figure presented a large part of     

Organic Pollutants in Coastal Waters,Sediments, and Biota: A Relevant Driver for Ecosystems During the Anthropocene?

The total number of synthetic organic chemicals introduced to the environment by humans has never been quantified, but it is not lower than thousands. A fraction of these chemicals have toxic effects to coastal organisms and presumably affect ecosystems structure and function. During the last decades, some of the processes affecting the transport, degradation, and fate of a limited number of chemicals have been studied, and the rising concern for environmental risk of organic chemical has lead to the regulation of a few of them by national and international organisms. However, the environmental inventory of organic pollutants is far from being quantified, and current methodologies used in most toxicological tests only allow to determine effects of individual chemicals to organisms. There are major limitations on appropriate methodologies to assess the effects of organic pollutants at population and ecosystem levels and the effects induced by complex mixtures of organic pollutants present in natural environments. The modification of the composition of the biosphere by a myriad of organic pollutants at ultra-trace levels is not yet regarded as another vector of environmental change which is irreversible due to the persistent character of many of these chemicals and due to its global coverage. Here, we claim that the modification of the atmosphere, water, sediments, and biota composition is a factor to be taken into account in coastal ecosystems, and that its pressure on the environment has been exponentially increasing during the last six decades of the anthropocene.     

Record-High Losses for Weather Disasters in the United States During the 1990s: How Excessive and Why?

During 1990–1996 the United States experienced record-setting insured property losses due to numerous weather catastrophes, each event causing $100 million or more in losses (1991 dollars). The total loss in this 7-year period, after adjustment to inflation and other factors, was $39.65 billion with $15 billion coming from one event, Hurricane Andrew. In the 1990s, 72 catastrophes occurred, half of the total number in the 40 preceding years, 1950–1989. Although the total loss and the number of catastrophes were exceptionally high in the 1990s, the average loss per event was $551 million, only slightly more than the $467 million average for catastrophes during 1950–1989. Furthermore, storm intensities in the 1990s were slightly less than those during the preceding 40 years, revealing the excess losses of the 1990s to be a result of an extremely large number of damaging storms causing losses exceeding $100 million. Examination of historical values of most weather extremes including hurricanes, floods, and tornadoes, did not show an increase during the 1990s, revealing that weather changes were not the principal cause of more catastrophes. Examination of recent demographic shifts in the U.S. reveals two changes, each based on major re-locations to higher-valued property concentrated in areas either with a high frequency of damaging storms (Gulf and East Coast), or to where even a small but intense storm can cause huge losses (urban areas and West Coast). These shifts, plus the continuing growth of population in other storm-prone areas have greatly increased society's vulnerability to storm damage. An in-depth analysis of many conditions was required to establish that the high losses and numerous catastrophes of the 1990s were largely the result of societal changes and not major weather changes. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Lichi Mélange in Coastal Range, eastern Taiwan:its origin, mechanism and evolution

Marine surveys show that the submarine Huatung Ridge extends northward to the Lichi Mélange in the southwestern Coastal Range, suggesting that formation of the Lichi Mélange is related to the arcward thrusting of the forearc strata in the western part of the North Luzon Trough during the active arc-continent collision off southern Taiwan. New seismic survey along 21oN transact across over the North Luzon Trough in the in-cipient arc-continent collision zone further reveals that the deformation of the Huatung Ridge occurs soon after the sedimentation in the western forearc basin, while the sedimentation is continuous in the eastern part of the remnant North Luzon Trough until the complete closure of the forearc basin approaching to SE Taiwan. This suggests that the sequence in the Huatung Ridge can just be coeval to the lower sequence of the remnant forearc basin strata. Multiple lines of new evidence, including micropaleontology, clay mineralogy and fis-sion track analyses along the Mukeng River and its tributary key sections, are used to test this thrusting forearc origin hypothesis of the Lichi Mélange.     

Mercury in the Tinto-Odiel Estuarine System (Gulf of Cádiz, Spain): Sources and Dispersion

The Tinto and Odiel are small rivers draining one of the largest sulphide deposits in the world. As a result of these deposits and a large industrial complex, the adjacent marine area receives a high amount of metal input. Mercury distribution in the Tinto-Odiel estuary, the Huelva Ría and the Gulf of Cádiz was assessed in water and suspended particulatematter (SPM) and sediments. In the rivers and estuaries, dissolved (HgD)and particulate (HgP) mercury showed wide variations (13 to 200 pM and0.3 to 330 nmol g^-1 respectively) depending on the presence or notof sulphidic waters, phosphogypsum deposits, detrital pyrite and oxyhydroxides.In the Ría, concentrations were lower than 10 pM and 4.5 nmol g^-1 for HgD and HgP respectively. In surface waters of the Gulf of Cádiz, the average HgD concentration (pm standard deviation) was 2.9 pm 0.9 pM, which is similar to that of North Atlantic Central Waters. The surface sediments collected in the rivers, the Ría and the Gulf showed systematically enriched mercury compared to pre-industrial levels. Vertical mercury profiles in dated sediment cores were typical of anthropogenically influenced environments starting in the early Roman age. These distribution features suggest that most of the Hg discharged by the Huelva Ría is trapped in the sediments of the Gulf of Cádiz.     

Erosion and Flooding—Threats to Coastal Infrastructure in the Arctic: A Case Study from Herschel Island,Yukon Territory,Canada

Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale. The objectives of this paper are to provide such a tool by assessing potential erosion and flood hazards at Herschel Island, a UNESCO World Heritage candidate site. This study focused on Simpson Point and the adjacent coastal sections because of their archeological, historical, and cultural significance. Shoreline movement was analyzed using the Digital Shoreline Analysis System (DSAS) after digitizing shorelines from 1952, 1970, 2000, and 2011. For purposes of this analysis, the coast was divided in seven coastal reaches (CRs) reflecting different morphologies and/or exposures. Using linear regression rates obtained from these data, projections of shoreline position were made for 20 and 50 years into the future. Flood hazard was assessed using a least cost path analysis based on a high-resolution light detection and ranging (LiDAR) dataset and current Intergovernmental Panel on Climate Change sea level estimates. Widespread erosion characterizes the study area. The rate of shoreline movement in different periods of the study ranges from ?5.5 to 2.7 m·a^?1 (mean ?0.6 m·a^?1). Mean coastal retreat decreased from ?0.6 m·a^?1 to ?0.5 m·a^?1, for 1952–1970 and 1970–2000, respectively, and increased to ?1.3 m·a^?1 in the period 2000–2011. Ice-rich coastal sections most exposed to wave attack exhibited the highest rates of coastal retreat. The geohazard map combines shoreline projections and flood hazard analyses to show that most of the spit area has extreme or very high flood hazard potential, and some buildings are vulnerable to coastal erosion. This study demonstrates that transgressive forcing may provide ample sediment for the expansion of depositional landforms, while growing more susceptible to overwash and flooding.     

How Do Surficial Lithic Assemblages Weather in Arid Environments? A Case Study from the Atacama Desert,Northern Chile

Archaeological sites composed only of surficial lithics are widespread in arid environments. Numerical dating of such sites is challenging, however, and even establishing a relative chronology can be daunting. One potentially helpful method for assigning relative chronologies is to use lithic weathering, on the assumption that the most weathered artifacts are also the oldest. Yet, few studies have systematically assessed how local environmental processes affect weathering of surficial lithics. Using macroscopic analyses, we compared the weathering of surficial lithic assemblages from seven mid‐to‐late Holocene archaeological sites sampled from four different microenvironments in the Atacama Desert of northern Chile. Changes in polish, texture, shine, and color were used to establish significant differences in weathering between two kinds of locations: interfluves and canyon sites. Lithics from interfluve sites were moderately to highly weathered by wind and possessed a dark coating, whereas canyon lithics were mildly weathered despite greater exposure to moisture, often lacked indications of eolian abrasion, and lacked dark coatings. Our results show that lithic weathering can be used as a proxy for relative age, but only after considering local environmental factors. The power of such chronologies can be improved by combining archaeological, paleoenvironmental, geomorphological, and taphonomic data.     

Physiological characteristics,geochemical properties and hydrological variables influencing pathogen migration in subsurface system: What we know or not?

The global outbreak of coronavirus infectious disease-2019 (COVID-19) draws attentions in the transport and spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in aerosols, wastewater, surface water and solid wastes. As pathogens eventually enter the subsurface system, e.g., soils in the vadose zone and groundwater in the aquifers, they might survive for a prolonged period of time owing to the uniqueness of subsurface environment. In addition, pathogens can transport in groundwater and contaminate surrounding drinking water sources, possessing long-term and concealed risks to human society. This work critically reviews the influential factors of pathogen migration, unravelling the impacts of pathogenic characteristics, vadose zone physiochemical properties and hydrological variables on the migration of typical pathogens in subsurface system. An assessment algorithm and two rating/weighting schemes are proposed to evaluate the migration abilities and risks of pathogens in subsurface environment. As there is still no evidence about the presence and distribution of SARS-CoV-2 in the vadose zones and aquifers, this study also discusses the migration potential and behavior of SARS-CoV-2 viruses in subsurface environment, offering prospective clues and suggestions for its potential risks in drinking water and effective prevention and control from hydrogeological points of view.     

Is REDD+ effective,efficient, and equitable? Learning from a REDD+ project in Northern Cambodia

REDD+ is a global scale climate change mitigation program aiming at creating financial values for carbon stored in forests. According to the proponents, REDD+ is an effective, efficient, and equitable mechanism for reducing emissions from deforestation and forest degradation. Some scholars question this assumption, and some call for further analysis to understand how REDD+ can contribute to economic, environmental, and social goals, and what are the synergies and trade-offs between them. The purpose of this paper is to contribute to the debate about whether REDD+ projects can be brought to accommodate economic (efficiency), environmental (effectiveness), and social (equity) concerns at the same time by drawing on own field results from a REDD+ project in Cambodia. The paper follows three tracks. The first is to develop and explain the conceptual and analytical framework for our empirical investigations. The second is to explain the field results. The third track is to discuss what general lessons can be learnt. Our case illustrates some of the mechanisms that are likely to work against the willingness and ability of REDD+ projects to ensure local people’s net-gains, and the risk that effectiveness and equity will suffer if REDD+ projects rely solely on the private market. Our case thus indicates a tension between the objectives of creating financial value from carbon stored in trees through the private market, and environmental and social equity concerns. However, we call for more comparative studies of REDD+ projects, and hope our conceptual framework can assist such studies.     

How deceptive are microstructures in granitic rocks? Answers from integrated physical theory,phase equilibrium,and direct observations

In this contribution, we address the vexed question of the extent to which microstructures in granitic rocks reflect their igneous histories or have been masked by later events. The previous works have tended to address the problem either using theoretical or modelling considerations, or by interpretation of observed microstructures. Here, we use an approach that integrates the theory of microstructural development and the results of experimental phase-equilibrium studies with direct observation of natural examples on a variety of scales. We show that the predictions of the theoretical and experimental approaches agree perfectly with the mesoscopic and microscopic evidence from granitic rocks themselves. Our conclusion is that although, in many cases, granitic rock microstructures have been modified by near-solidus reactions and crystallisation, in the absence of tectonic deformation the fundamental elements of their igneous heritage remain intact. This means that it is perfectly in order to infer aspects of crystallisation sequences, magmatic reactions, and magma flow through careful microstructural observations. Thus, our answer to the question of how deceptive granitic textures are is, in most instances, ‘not very’. However, some undeformed plutons have undergone fluid-driven alteration, and others have been affected by contact metamorphism. Thus, each case should be examined on its own merits.     

What has happened in Spain? The real estate bubble,corruption and housing development: A view from the local level

How have the recent real estate, mortgage and financial crises affected different countries, territories and cities? How have the different public and private stakeholders behaved and how accountable have they been for the origin and development thereof? What links are there among the local, national and global contexts in the crises? Recent geographic research ought to attempt to answer these questions, but there have, however, been few in-depth studies on the link between urbanisation, financial markets and the global crisis. The present paper analyses one of the principal causes of Spain’s recent evolution: urbanisation of the territory, the start and consequences of housing bubble; our study emphasises the differential elements in relation to the crisis in other countries. We study in greater depth the municipality of Torrelodones, which constitutes a reference due to the appearance of a residents’ movement opposed to the development process and which is a perfect example of the dynamics that led to the economic and social crisis. We describe in detail the lack of any strategic vision, participation or transparency in town planning decision-making, the processes by which reports and inspections were doctored, and the mechanisms of corruption of public decision-making in town planning. Finally, we analyse the concrete manner in which huge losses in mortgage markets occurred, with the collapse of the real estate bubble and the financial markets, which subsequently forced a State bailout.     

Is shrinking groundwater resources leading to socioeconomic and environmental degradation in Central Ganga Plain,India?

In India, agriculture is a source of livelihood for over 64 % of the country's population. Indo-Gangetic Plains of North India support good cultivation and provides livelihood to several hundred million people. The climatic change studies have documented changes in precipitation pattern which can alter the flow pattern discharge to the reservoirs and availability of water for agriculture. The reduction in groundwater recharge through reduced rainfall and irregularity in surface water availability has increased dependence on groundwater resources causing its overexploitation. Consequently, pumping from deeper groundwater conditions need more energy and pump efficiency for abstraction which ultimately requires huge capital investment. Moreover, volatile fuel prices make the agricultural society vulnerable to economic losses. The repercussions of water level decline are likely to disseminate an additional economic burden to the groundwater user community. To cope with higher energy demands, increase in fuel consumption has led to environmental degradation through higher carbon emission. Thus, the groundwater depletion is likely to have far-reaching socioeconomic and environmental impacts which are not confined to the Central Gangetic Plain. In the present study, attempts have been made to analyze the effect of groundwater depletion as a commodity in the social framework of the region.     

Ambient well-bore mixing, aquifer cross-contamination, pumping stress, and water quality from long-screened wells: What is sampled and what is not?

Water quality tests were performed on two long-screened alluvial aquifer wells (15–30 m of screen) that had been completed in a heterogeneous aquifer that exhibits extreme temporal water quality variability. When stressed, the total dissolved solids (TDS) in one well decreased from 10,600 to 3,500 mg/L and in another well the TDS increased from 136 to 2,255 mg/L. Nested short-screened monitoring wells were constructed in chemically distinct horizons affecting each well. Water level measurements and solute and isotopic samples were obtained from the production wells and the monitoring wells during a water quality test. Results of a time drawdown tests demonstrate transmissivity differences between horizons. Ambient water quality in the production wells and aquifer cross-contamination are controlled by well-bore mixing due to head differences of as little as 0.01 m between chemically distinct horizons which are linked by the production well screen. During non-stress periods, the ambient well-bore chemistry is controlled by the horizon with the greatest hydraulic head, whereas during stressed conditions, horizon transmissivity controls the well-bore chemistry. In one well, aquifer cross-contamination, driven by an ambient head differential of 1.2 m, persisted until about 1,600 well-bore volumes were purged.     

How big,how bad,how often: are extreme events accounted for in modern seismic hazard analyses?

The occurrence of several recent “extreme” earthquakes with their significant loss of life and the apparent failure to have been prepared for such disasters has raised the question of whether such events are accounted for in modern seismic hazard analyses. In light of the great 2011 Tohoku-Oki earthquake, were the questions of “how big, how bad, and how often” addressed in probabilistic seismic hazard analyses (PSHA) in Japan, one of the most earthquake-prone but most earthquake-prepared countries in the world? The guidance on how to properly perform PSHAs exists but may not be followed for a whole range of reasons, not all technical. One of the major emphases of these guidelines is that it must be recognized that there are significant uncertainties in our knowledge of earthquake processes and these uncertainties need to be fully incorporated into PSHAs. If such uncertainties are properly accounted for in PSHA, extreme events can be accounted for more often than not. This is not to say that no surprises will occur. That is the nature of trying to characterize a natural process such as earthquake generation whose properties also have random (aleatory) uncertainties. It must be stressed that no PSHA is ever final because new information and data need to be continuously monitored and addressed, often requiring an updated PSHA.