Marine Location Research Articles

Research on Rural Tourism Design in Zhejiang under Sustainable Cultural Development

Background and Aim: Zhejiang Province of China is located in China's East China Sea, is China's ports in the province, the province's famous fishing villages are known to fish a lot of unique marine location advantages formed distinctive fishermen's living customs, but also gradually formed a rich and colorful fishing culture in Zhejiang. Therefore, the sustainable tourism development of Zhejiang fishing villages is closely related to the overall economic level of Zhejiang Province. By searching for the characteristics of fishing villages in Zhejiang Province, we create a suitable image design and model and develop and promote it, to promote the development of sustainable cultural tourism in beautiful villages. Materials and Methods: Based on the perspective of sustainable development, this paper analyses and integrates the characteristics of the "Chinese Fishing Village" in Zhejiang Province from three aspects through literature research, field survey, and questionnaire survey, applying the concept of sustainable development and the strategy of CI to design an image design and model of sustainable development that meets the requirements of the Chinese fishing village, and promote it to the life of the fishing village. The image design and model of sustainable development of the "Chinese fishing village" are designed and promoted to the life of the fishing village, and the visual image of the sustainable development concept is set up, which helps to disseminate the core concept and spirit of the concept, to enhance the influence of the fishing village and to design and promote the common sustainable cultural development of the fishing village. Results: The study found that the characteristics of the "Chinese fishing village" in Xiangshan County, Zhejiang Province, China, combined the resource base of fishing culture and art in the fishing village with the brand communication, and designed a sustainable development model to take fishing culture as the core of the development, develop fishing culture resources, do a good job of promoting the fishing culture and increase the development of cultural and creative products, to promote the sustainable cultural tourism development of the village. sustainable cultural tourism development. Conclusion: Based on the results of the study, this paper derives image designs and models that contribute to the development of sustainable cultural tourism in villages.

Drowned Places: Sea-Level Rise and Narrative Crisis in Elizabeth Rush's Rising

Anthropogenic sea-level rise is forcing—and will force—extraordinary measures in adaptation and retreat. At the same time, it is compelling conventions in aesthetics, geography, and narrative to contend with fundamental challenges to description, reference, perception, and place. This article examines Elizabeth Rush's Rising: Dispatches from the New American Shore (2018), an ambitious and sensitive account of the impacts of sea-level rise on coastal communities in the United States. Among Rising's proliferating seascapes, inundation tends to entail a fundamental loss of place, and open waters tend to prove inhospitable to history and memory. The article situates these tendencies among theories of aqueous and marine location, systems of narrative reference, and settler-colonial traditions in spatiality. I read Rising as a statement, poignant and perturbing, of anthropogenic sea-level rise as a creeping catastrophe for certain conventions in interpretation, imagination, and representation—and an impetus to recognize and amplify alternate ontologies. My wider purpose is threefold: to furnish one method for accessing and interpreting the literatures of sea-level rise; to identify the imaginative constraints impinging on certain liquid imaginaries; and to gesture toward the presence and promise of other visions. I aim, ultimately, to help demonstrate the poetic polysemy that incoming waters can be heard, and read, to supply—and to make place for the voices of those who are helping situate their, and "our," watery futures.

Ispitivanje prirodnog starenja polikarbonata srednje i visoke molekulske mase na kontinentalnoj i morskoj lokaciji za period od 96 meseci

Two thermoplastic polycarbonate bisphenol A types were exposed to the influence of natural weathering at continental location and at marine location for a period of 8 years (96 months). Every six months the specimens of medium molecular weight polycarbonate and high molecular weight polycarbonate were taken from mentioned locations and tested. Seven characteristics were chosen for determination of quality before exposition and during the process of degradation of two mentioned polycarbonate types (tensile strength, elongation to break, Shore hardness, Vicat softening point, water absorption, density and Charpy impact resistance). Changes of these seven properties at continental location are similar to the changes of mentioned characteristics at marine location during specified period of time. Data obtained by testing specimens of medium molecular weight polycarbonate pointed out that there were two important changes of quality regarding elongation to break and Charpy impact resistance (first after 36 months and second after 54 months of exposure). After 96 months of natural weathering of the above-mentioned material at both locations meaningful drop of tensile strength, moderate change of water absorption and negligible changes of Shore hardness, Vicat softening point and density were recorded. The influence of molecular weight is very apparent because high molecular weight polycarbonate exhibited higher resistance to the degradation process in natural conditions. Two very important characteristics of this polycarbonate material (tensile strength and Charpy impact resistance) practically did not change during 96 months of exposition in an open air, while drop of elongation to break is meaningful, diminution of water absorption is moderate and changes of Shore hardness, Vicat softening point and density are very small.

A fast and accurate LEO satellite-based direct position determination assisted by TDOA measurements

This paper focuses on the trusted vessel position acquisition using passive localization based on the booming low-earth-orbit (LEO) satellites. As the high signal-to-noise ratio (SNR) reception cannot always be guaranteed at LEO satellites, the recently developed direct position determination (DPD) is adopted. For LEO satellite-based passive localization systems, an efficient DPD is challenging due to the excessive exhaustive search range leading from broad satellite coverage. In order to reduce the computational complexity, we propose a time difference of arrival-assisted DPD (TA-DPD) which minimizes the searching area by the time difference of arrival measurements and their variances. In this way, the size of the searching area is determined by both geometrical constraints and qualities of received signals, and signals with higher SNRs can be positioned more efficiently as their searching areas are generally smaller. Both two-dimensional and three-dimensional passive localization simulations using the proposed TA-DPD are provided to demonstrate its efficiency and validity. The superior accuracy performance of the proposed method, especially at low SNRs conditions, is also verified through the comparison to conventional two-step methods. Providing a larger margin in link budget for satellite-based vessel location acquisition, the TA-DPD can be a competitive candidate for trusted marine location service.

Preparation and Characterization of Pour‐Casting Red Phosphorus Smoke Agents with HTPB as Binder

AbstractThe main aim of this study is to develop the vacuum pour‐casting process of the red phosphorus smoke agents. The typical composition of MK 58 marine location marker prepared by tamp‐casting process is red phosphorus (RP)/magnesium (Mg)/manganese dioxide (MnO2)/zinc oxide (ZnO)/epoxy resin (ER), which was selected as the original formula. Epoxy resin (ER) was replaced by hydroxyl terminated polybutadiene (HTPB) as the binder. First of all, simultaneous differential scanning calorimetry‐thermogravimetric analysis (STA DSC‐TGA) and vacuum stability tester (VST) were used to analyze the thermochemical characteristics, stability and chemical compatibility of the formula. Afterwards, Taguchi's experimental design method was used to design nine experimental conditions by way of orthogonal array with four control factors and three levels, and the scaled‐down smoke pellets were prepared using the vacuum pour‐casting method. The combustion phenomenon of these smoke pellets was recorded by the visual‐image capture system, and the flame temperature was measured by the temperature measurement system. The burning rate was chosen as the quality characteristic to analyze the optimal parameter combination of minimum burning rate. In addition, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM‐EDS), tensile testing machine (TTM) and hardness tester (HT) were employed to observe the uniformity of the composition distribution in the pellet and to measure the mechanical strength and hardness of the pellets. Smoke density test chamber (SDTC) was used to measure the specific optical density of smoke generated by RP smoke agent. Finally, the operating conditions of the optimal parameter combination determined by Taguchi method were used to prepare the full‐size smoke candle, and its burning performance was verified and the feasibility of the vacuum pour‐casting technology was evaluated. The experimental results indicated that the optimal combination of parameters was the RP mixture/HTPB mass ratio of 84 : 16, the NCO/OH ratio of IPDI to HTPB (R value) of 1.6, the additional DOA of 4.5 wt % and the curing temperature of 50 °C. The prepared scaled‐down smoke pellets had good stability, chemical compatibility, hardness, mechanical properties and burning smoke density. In addition, the burning time and performance of the full‐size smoke candles prepared by vacuum pour‐casting technology also met the requirements.

COMPATIBILITY OF INDONESIA’S REGULATIONS ON SUBMARINE CABLE WITH UNCLOS 1982

The special status of Exclusive Economic Zone of Indonesia (EEZ) raises a problem particularly related to the submarine cable laying activities. This study aims to analyze the compatibility of the marine location permit instrument under Law No. 32/2014 on Marine Affairs and Government Regulation No. 32/2019 on National Marine Spatial Planning (MSP) with UNCLOS 1982 in regulating submarine cable in the EEZ. This normative research shows that the marine location permit instrument regulating submarine cable laying activity in EEZ is incompatible with the provisions of UNCLOS 1982. In contrast, the MSP instrument is compatible and a suitable instrument to protect Indonesia's interests in the EEZ. The Government of Indonesia is advised to regulate an exemption clause for submarine cable installation in EEZ in the Draft of Government Regulation on Marine Location Permit; formulate and formalize ‘prior notification’ procedures by other countries in submarine cable laying activities in EEZ into laws and regulations; and publish the Government Regulation on Marine Spatial Planning and its annexes through the channels of relevant international organizations such as International Cable Protection Committee (ICPC) and Intergovernmental Oceanographic Commission (IOC).

Measuring Temperature in Coral Reef Environments: Experience, Lessons, and Results from Palau

Sea surface temperature, determined remotely by satellite (SSST), measures only the thin “skin” of the ocean but is widely used to quantify the thermal regimes on coral reefs across the globe. In situ measurements of temperature complements global satellite sea surface temperature with more accurate measurements at specific locations/depths on reefs and more detailed data. In 1999, an in situ temperature-monitoring network was started in the Republic of Palau after the 1998 coral bleaching event. Over two decades the network has grown to 70+ stations and 150+ instruments covering a 700 km wide geographic swath of the western Pacific dominated by multiple oceanic currents. The specific instruments used, depths, sampling intervals, precision, and accuracy are considered with two goals: to provide comprehensive general coverage to inform global considerations of temperature patterns/changes and to document the thermal dynamics of many specific habitats found within a highly diverse tropical marine location. Short-term in situ temperature monitoring may not capture broad patterns, particularly with regard to El Niño/La Niña cycles that produce extreme differences. Sampling over two decades has documented large T signals often invisible to SSST from (1) internal waves on time scales of minutes to hours, (2) El Niño on time scales of weeks to years, and (3) decadal-scale trends of +0.2 °C per decade. Network data have been used to create a regression model with SSST and sea surface height (SSH) capable of predicting depth-varying thermal stress. The large temporal, horizontal, and vertical variability noted by the network has further implications for thermal stress on the reef. There is a dearth of definitive thermal information for most coral reef habitats, which undermines the ability to interpret biological events from the most basic physical perspective.

A Continental and Marine-Influenced Tree-Ring Mercury Record in the Old Crow Flats, Yukon, Canada

Gaseous elemental mercury (Hg0) concentrations in the atmosphere have been increasing due to anthropogenic activities since the onset of colonial mining in the 17th century. However, accurate measurements of atmospheric Hg, including temporal trends, are mostly limited to recent decades. Natural environmental archives including tree rings show promise for reconstructing atmospheric concentrations of Hg0. In this paper, we present a new white spruce (Picea glauca) tree-ring Hg record (1696–2005) from the Old Crow Flats in northern Yukon. The record we present shows an increase in tree-ring Hg concentration (a proxy for gaseous Hg0 concentration) between 1748 and 1990 at a rate of +3.3% per year. A decrease in measured Hg is observed at the end of the record between 1990 and 2005, which may reflect the success of international regulations to reduce emissions including Hg. When compared with two other sites (a continental and marine location) in northwest Canada, there is not only some coherence in Hg trends at the regional scale but also some unique differences, suggesting that the location may influence atmospheric Hg0 available for assimilation. Further local factors within a site, such as soil moisture, may also affect the efficiency of this uptake. Results from this study highlight the need to better understand intra-site and inter-site differences in measured tree-ring Hg, and we recommend the continued development of a spatially resolved tree-ring Hg network in the northern boreal forest. Such records will be useful for developing better atmospheric Hg and global Hg models.

Inducing the attachment of cable bacteria on oxidizing electrodes

Abstract. Cable bacteria (CB) are multicellular, filamentous bacteria within the family of Desulfobulbaceae that transfer electrons longitudinally from cell to cell to couple sulfide oxidation and oxygen reduction in surficial aquatic sediments. In the present study, electrochemical reactors that contain natural sediments are introduced as a tool for investigating the growth of CB on electrodes poised at an oxidizing potential. Our experiments utilized sediments from Yaquina Bay, Oregon, USA, and we include new phylogenetic analyses of separated filaments to confirm that CB from this marine location cluster with the genus “Candidatus Electrothrix”. These CB may belong to a distinctive lineage, however, because their filaments contain smaller cells and a lower number of longitudinal ridges compared to cables described from other locales. The results of a 135 d bioelectrochemical reactor experiment confirmed that these CB can migrate out of reducing sediments and grow on oxidatively poised electrodes suspended in anaerobic seawater. CB filaments and several other morphologies of Desulfobulbaceae cells were observed by scanning electron microscopy and fluorescence in situ hybridization on electrode surfaces, albeit in low densities and often obscured by mineral precipitation. These findings provide new information to suggest what kinds of conditions will induce CB to perform electron donation to an electrode surface, further informing future experiments to culture CB outside of a sediment matrix.

Prediction of seismic P-wave velocity using machine learning

Abstract. Measurements of seismic velocity as a function of depth are generally restricted to borehole locations and are therefore sparse in the world's oceans. Consequently, in the absence of measurements or suitable seismic data, studies requiring knowledge of seismic velocities often obtain these from simple empirical relationships. However, empirically derived velocities may be inaccurate, as they are typically limited to certain geological settings, and other parameters potentially influencing seismic velocities, such as depth to basement, crustal age, or heat flow, are not taken into account. Here, we present a machine learning approach to predict the overall trend of seismic P-wave velocity (vp) as a function of depth (z) for any marine location. Based on a training dataset consisting of vp(z) data from 333 boreholes and 38 geological and spatial predictors obtained from publicly available global datasets, a prediction model was created using the random forests method. In 60 % of the tested locations, the predicted seismic velocities were superior to those calculated empirically. The results indicate a promising potential for global prediction of vp(z) data, which will allow the improvement of geophysical models in areas lacking first-hand velocity data.

Last Glacial Maximum, early Holocene and modern environments of the northern South China Sea region: Insight from SEM analysis of Oak (Quercus) pollen.

Oak (Quercus) pollen was identified at the infra-generic (i.e. sub-genus to species) utilizing Scanning Electron Microscope (SEM) images of modern (i.e. 18 species from southern China) and fossil pollen grains from northern South China Sea (SCS) marine and terrestrial sediments. Key morphological characteristics of Quercus exine sculpture were used to separate the pollen into evergreen and deciduous groups, with this distinction applied to the fossil oak pollen from the Last Glacial Maximum (LGM) and early Holocene periods. The presence of Quercus pollen from the modern Pearl River and northern SCS suggests long distance transport from inland temperate to tropical regions surrounding the SCS. Fossil oak pollen from terrestrial and marine sediments from the northern SCS region suggests different pollen representation between these two sedimentary environments, with the terrestrial site dominated by evergreen Quercus types and the marine location showing greater representation of deciduous oak species. The presence of both evergreen and deciduous oak pollen in the LGM age marine sediments suggests only moderate cooling during this time period, while the dramatic increase of deciduous Quercus pollen in the marine core, as well as generally higher pollen influx values, reflects greater fluvial discharge, which in turn is linked to increased precipitation in the region during the early Holocene period.

Small-scale Experimental Testing of a Novel Marine Floating Platform with Integrated Hydro-pneumatic Energy Storage

Co-locating energy storage within the floating platform of offshore renewable energy systems is an effective way of reducing the cost and environmental footprint of marine energy storage devices. However, the development of suitable, non-hazardous technologies, and the influence of the marine environment on their efficiency remains an open problem. Research at the University of Malta has culminated in the Floating Liquid-piston Accumulator using Seawater under Compression (FLASC) concept, a solution involving hydro-pneumatic energy storage tailored for offshore renewables. A small-scale prototype was deployed at a sheltered marine location in the Maltese Islands, in the central Mediterranean Sea. The aim of the experimental campaign was to measure the performance of the energy storage system, and to quantify the effects of different system parameters along with the surrounding meteorological conditions. Results from selected charging-discharging cycles are presented, these include different scheduling schemes and pressure ranges. Overall, results indicate that the experimental system consistently demonstrated a high thermal efficiency (> 93%) across hundreds of charging cycles. Operating pressure range and charging schedule play a limited role on the hydro-pneumatic process, whereas seasonal temperature changes play a more significant role, in that such changes can slightly alter the effective storage capacity of the system. Results from this experimental work provide a practical proof-of-concept for hydro-pneumatic marine energy storage, and can enable key conclusions to be drawn providing a basis to numerous ongoing developments in fluid-based energy storage systems for offshore implementation.

Feasibility of offshore wind energy as an alternative source for the state of Kuwait

The techno economic feasibility of offshore wind energy potential for Kuwait was assessed. The main objective was focused on selecting right locations for commercial wind mill erections. The measured wind speed from Directorate General of Civil Aviation, Kuwait for eight offshore stations during January 2012 to December 2015 was used and the parameters of Weibull distributions and wind power densities are estimated at an extrapolated elevation of 30-m from mean sea level. It is found that the best marine location was Beacon N6, just 3 km south of Boubiyan Island with wind power density of 583.2 W/m2 during summer. It was found that the wind power density near the coastal area peak in summer, which is good, since in summer, the demand for energy is high. The next highest wind power density was at South Dolphin and Ahmadi oil pier area, which is also closer to mainland. The wind power density was also found to be high at offshore locations such as Sea Island Buoy, Umm Al-Maradim, and Beacon M28 during winter. In Kuwait, the wave climate is moderate and the water depths are less than 20 m for most of the sites. Economic analysis is carried for a 50 MW offshore wind mill and is compared with 800 MW thermal power plant. From this analysis, it is found that power production/kWh from offshore wind turbines will be about 30% cheaper compared to the oil based thermal power plant.

Population, habitat, and marine location effects on early marine survival and behavior of Puget Sound steelhead smolts

AbstractSteelhead trout (Onchorhynchus mykiss) smolts suffer high mortality rates during their rapid migration through the Salish Sea. Among‐population variability in mortality rates may reflect (1) genetic fitness variation among populations, (2) freshwater environmental effects on fish condition, or (3) differences in local marine conditions upon seawater entry. A reciprocal transplant experiment was conducted to separate the influence of freshwater effects (combined effects of population and freshwater environment) from effects of local marine conditions on survival of two Puget Sound steelhead populations. Steelhead smolts from the Green River in Central Puget Sound (urbanized and hatchery‐influenced) and the Nisqually River in South Puget Sound (less urbanized; no hatchery influence) were tagged with acoustic telemetry transmitters and released back into their natal river or transported and released into the other river. Population of origin had little influence on probability of surviving the migration through Puget Sound. However, smolts released into the Green River had higher survival through Puget Sound (17%) than smolts released into the Nisqually River (6%); the extra 64‐km migration segment for the Nisqually‐released fish accounted for most of the difference between the two release locations. Neither fork length nor translocation influenced survival, though release date did affect survival of Nisqually population smolts regardless of their release location. Residence time and behavior in the two estuaries were similar, and no effects of population of origin or release date were evident. Marine travel rates also did not differ between populations, release dates, or release locations. This study indicates that mortality occurring in the Salish Sea is likely driven by processes in inland marine environments, more so than intrinsic effects of population or freshwater‐rearing environments.

Effect of KCl and MgCl2 on the kinetics of methane hydrate formation and dissociation in sandy sediments

Natural gas hydrate is one of the potential energy resources in the future. However, the extraction of energy from hydrates remains uncertain due to limited understanding on how hydrates are formed and dissociated under different perturbations. More than 90% of NGH resource exists within marine location where salts are present. In this study, we investigated the formation and dissociation behavior of methane hydrate in the presence of magnesium chloride (MgCl2) and potassium chloride (KCl), two salts found in seawater, at 1.5 wt% and 3.0 wt%; and compared it with the cases of water and NaCl from our previous work. We found that on top of thermodynamic inhibition, both MgCl2 and KCl act as kinetic inhibitors on hydrate formation, retarding the rate of formation – with KCl exhibiting a weaker inhibition compared to MgCl2. For hydrate dissociation via thermal stimulation, we demonstrated that hydrate dissociates more rapidly in the presence of salts as compared to water despite a comparable temperature driving force (ΔT = 5.3 K) applied. Our results indicated that the weaker thermodynamic inhibitor, KCl, has a milder kinetic inhibition effect on hydrate formation and a weaker promoting effect on hydrate dissociation as compared to MgCl2 and NaCl.

Thiol-Based Selective Extraction Assay to Comparatively Assess Bioavailable Mercury in Sediments.

Bioaccumulation of methylmercury in the aquatic food web is governed in part by the methylation of inorganic divalent mercury (Hg(II)) by anaerobic microorganisms. In sulfidic settings, a small fraction of total Hg(II) is typically bioavailable to methylating microorganisms. Quantification of this fraction is difficult due to uncertainties in the speciation of Hg(II) and the mechanisms of uptake by methylating microbes. However, recent studies have shown that the bioavailable fraction is likely to include a portion of Hg(II) associated with solid phases, that is, nanostructured mercuric sulfides. Moreover, addition of thiols to suspensions of methylating cultures coincides with increased uptake into cells and methylmercury production. Here, we present a thiol-based selective extraction assay to provide information on the bioavailable Hg fraction in sediments. In the procedure, sediment samples were exposed to a nitrogen-purged solution of glutathione (GSH) for 30 min and the amount of GSH-leachable mercury was quantified. In nine sediment samples from a marine location, the relative GSH-leachable mercury concentration was strongly correlated to the relative amount of methylmercury in the sediments (r2=0.91, p<0.0001) across an order of magnitude of methylmercury concentration values. The approach was further applied to anaerobic sediment slurry microcosm experiments in which sediments were cultured under the same microbial growth conditions but were amended with multiple forms of Hg with a known spectrum of bioavailability. GSH-leachable Hg concentrations increased with observed methylmercury concentrations in the microcosms, matching the trend of species bioavailability in our previous work. Results suggest that a thiol-based selective leaching approach is an improvement compared with other proposed methods to assess Hg bioavailability in sediment and that this approach could provide a basis for comparison of sites where Hg methylation is a concern.

A 12-year observation of water-soluble ions in TSP aerosols collected at a remote marine location in the western North Pacific: an outflow region of Asian dust

Abstract. In order to characterize the long-term trend of remote marine aerosols, a 12-year observation was conducted for water-soluble ions in TSP (total suspended particulate) aerosols collected from 2001 to 2012 in the Asian outflow region at Chichijima Island in the western North Pacific. We found a clear difference in chemical composition between the continentally affected and marine background air masses over the observation site. Asian continental air masses are delivered from late autumn to spring, whereas marine air masses were dominated in summer. Concentrations of non-sea salt (nss-) SO42−, NO3−, NH4+, nss-K+ and nss-Ca2+ are high in winter and spring and low in summer. On the other hand, MSA− (methanesulfonate) exhibits higher concentrations during spring and winter, probably due to springtime dust bloom or due to the direct continental transport of MSA− to the observation site. We could not find any clear decadal trend for Na+, Cl−, Mg2+ and nss-Ca2+ in all seasons, although there exists a clear seasonal trend. However, concentrations of nss-SO42− continuously decreased from 2007 to 2012, probably due to the decreased SO2 emissions in East Asia especially in China. In contrast, nss-K+ and MSA− concentrations continuously increased from 2001 to 2012 during winter and spring seasons, demonstrating that biomass burning and/or terrestrial biological emissions in East Asia are being increasingly transported from the Asian continent to the western North Pacific. This study also demonstrates that Asian dusts can act as an important source of nutrients for phytoplankton and thus sea-to-air emission of dimethyl sulfide over the western North Pacific.

Public engagement with offshore renewable energy: a critical review

Offshore renewable energy, including offshore wind, tidal and wave energy, has sometimes been represented as opposition‐free alternatives to controversial technologies such as onshore wind turbines, and has received increasing attention from social scientists in recent years. A fragmented literature has emerged investigating public engagement with these technologies and the determinants of public acceptance, comprising 59 key studies—the majority investigating offshore wind energy (59%). This literature review argues that while the ways in which public actors engage with offshore renewable energy are to some extent similar to onshore energy infrastructure, there are also important differences. These include the generally lower levels of public knowledge about the technologies, a changing role for visual impacts, a fundamentally different, marine, spatial context, and different sets of stakeholders in different decision‐making arenas. There is a need to explore as yet unasked and unanswered questions—going beyond ‘established’ variables identified in the onshore wind‐based ‘beyond NIMBY’ literature—especially regarding the role of the marine location of these technologies, and the cross‐technology and cross‐disciplinary applicability of findings. In order to more fully understand public responses to energy infrastructures, future research needs to move beyond case studies of onshore wind developments, adopting more diverse and ambitious research designs and methodologies.This article is categorized under: Perceptions, Behavior, and Communication of Climate Change &gt; Behavior Change and Responses

Orbitally-induced changes of the Atlantic and Indian monsoons over the past 20,000 years: New insights based on the comparison of continental and marine records

Abstract Variations of Atlantic and Indian monsoon systems since the last glacial period are investigated by comparing eolian fluxes from two marine cores (ODP site 658 off western Africa and core 74KL off the Arabian peninsula) with 2147 hydrological records (lacustrine, palustrine, spring and fluvial, arid) gathered over a large continental area extending between 10 and 30°N across Africa, Arabia and western India. We show that the hydrological response to the Holocene humid phase in the northern tropics strongly differs from a region to another. The humid period is significantly shorter in the Arabian peninsula and the horn of Africa compared to northern Africa even though its maximum is contemporaneous (11,000–7,000 cal yr BP). Western India displays a specific hydrological signal characterized by the importance of well-developed fluvial systems from the Himalayas and the paucity of lakes compared to the other regions. In western India, the humid peak is shifted toward the mid Holocene (8,000–6,000 cal yr BP). Both marine records show a peak between ~ 11,000 and 7,000 cal yr BP for the Holocene humid period, in good accordance with African-Arabian records. However, while continental hydrological data suggest that the onset and termination of this humid period might have been relatively progressive, the marine windborne records indicate abrupt transitions, somewhat out-of-phase with continental evidence (e.g. abrupt decrease of aeolian proxies as early as ~ 15,000 cal yr BP). Discrepancies between marine and continental likely result from the fact that aeolian fluxes at a given marine location do not simply record monsoon-related changes of humidity over the adjacent continental sources but could be affected also by changes of the source area (e.g., emersion of the Arabo-Persian gulf associated to the glacial, low sea-level stand), and changes in wind intensity and/or direction.

Dispersal kernel estimation: A comparison of empirical and modelled particle dispersion in a coastal marine system

Early life-stage dispersal influences recruitment and is of significance in explaining the distribution and connectivity of marine species. Motivations for quantifying dispersal range from biodiversity conservation to the design of marine reserves and the mitigation of species invasions. Here we compare estimates of real particle dispersion in a coastal marine environment with similar estimates provided by hydrodynamic modelling. We do so by using a system of magnetically attractive particles (MAPs) and a magnetic-collector array that provides measures of Lagrangian dispersion based on the time-integration of MAPs dispersing through the array. MAPs released as a point source in a coastal marine location dispersed through the collector array over a 5–7 d period. A virtual release and observed (real-time) environmental conditions were used in a high-resolution three-dimensional hydrodynamic model to estimate the dispersal of virtual particles (VPs). The number of MAPs captured throughout the collector array and the number of VPs that passed through each corresponding model location were enumerated and compared. Although VP dispersal reflected several aspects of the observed MAP dispersal, the comparisons demonstrated model sensitivity to the small-scale (random-walk) particle diffusivity parameter (Kp). The one-dimensional dispersal kernel for the MAPs had an e-folding scale estimate in the range of 5.19–11.44 km, while those from the model simulations were comparable at 1.89–6.52 km, and also demonstrated sensitivity to Kp. Variations among comparisons are related to the value of Kp used in modelling and are postulated to be related to MAP losses from the water column and (or) shear dispersion acting on the MAPs; a process that is constrained in the model. Our demonstration indicates a promising new way of 1) quantitatively and empirically estimating the dispersal kernel in aquatic systems, and 2) quantitatively assessing and (or) improving regional hydrodynamic models.