Marine artificial light at night:An empirical and technical guide

The increasing illumination of our world by artificial light at night (ALAN) has created a new field of global change research with impacts now being demonstrated across taxa, biological ranks and spatial scales. Following advances in terrestrial ecology, marine ALAN has become a rapidly growing research area attracting scientists from across all biomes. Technological limitations, complexities of researching many coastal and marine ecosystems and the interdisciplinary nature of ALAN research present numerous challenges. Drawing on expertise from optical oceanographers, modellers, community ecologists, experimental and molecular biologists, we share practical advice and solutions that have proven useful for marine ALAN research. Discussing lessons learnt early on can help in the effective and efficient development of a field. The guide follows a sensory ecology approach to marine light pollution and consolidates physics, ecology and biology. First, we introduce marine lightscapes highlighting how these differ from terrestrial ones and provide an overview of biological adaptations to them. Second, we discuss study design and technology to best quantify ALAN exposure of and impacts on marine and coastal organisms including molecular tools and approaches to scale-up marine ALAN research. We conclude that the growing field of marine ALAN research presents opportunities not only for improving our understanding of this globally widespread stressor, but also for advancing fundamental marine photobiology, chronobiology and night-time ecology. Interdisciplinary research will be essential to gain insights into natural marine lightscapes shaping the ecology and evolution coastal and marine ecosystems

Utility of remote sensing data in retrieval of water quality consituents concentrations in coastal water of New Jersey

Three important optical properties used for monitoring coastal water quality are the concentrations of chlorophyll (CHL), color dissolved organic matter (CDOM) and total suspended materials (TSM). Ocean color remote sensing, a technique to collect color data by detection of upward radiance from a distance (Bukata et al.,1995), provides a synoptic view for determining these concentrations from upwelling radiances. In the open ocean (Case-I), it is not difficult to derive empirical algorithms relating the received radiances to surface concentrations of water quality parameters. In coastal waters (Case-Il), there are serious unresolved problems in extracting chlorophyll concentration because of high concentration of suspended particles (Gordon and Morel, 1983). There are three basic approaches to estimate optical water quality parameters from remotely sensed spectral data based on the definitions given by Morel & Gordon (1980): (1) an empirical method, in which statistical relationships between the upward radiance at the sea surface and the quantity of interest are taken into account; (2) a semiempirical method, in which the spectral characteristics of the parameters of interest are known and some modeling of the physics is introduced; and (3) an analytical method, in which radiative transfer models are used to extract the inherent optical properties (lOPs) and a suite of analysis methods can be used to optimally retrieve the water constituents from the remotely sensed upwelling radiance or irradiance reflectance signal. The focus of this research is the modification and application of analytical and statistical algorithms to characterize the physically based surface spectral reflectance for the waters of the Hudson/Raritan Estuary and to retrieve the water constituent concentrations from the NASA Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and LIght Detection And Ranging (LIDAR) signals. The approaches used here are based on the unique capabilities of AVIRIS and LIDAR data which can potentially provide a better understanding of how sunlight interacts with estuarine/inland water, especially when complemented with in situ measurements for analysis of water quality parameters and eutrophication processes. The results of analysis in forms of thematic maps are then input into geographic information system (GIS) of the study site for use by water resource managers and planners for better monitoring and management of water quality condition

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research – MINe Analog Research (MINAR). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small-scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator, Close-Up Imager, Raman spectrometer, Small Planetary Linear Impulse Tool, Ultrasonic drill and handheld X-ray diffraction (XRD). We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimetre to metre scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research – MINe Analog Research (MINAR). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small-scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator, Close-Up Imager, Raman spectrometer, Small Planetary Linear Impulse Tool, Ultrasonic drill and handheld X-ray diffraction (XRD). We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimetre to metre scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining

Noise in Marine Seismic Data

Marine seismic is a well established method to search for subsurface hydrocarbon deposits. However, the method is often limited by various sources of noise, of which flow and swell noise are the dominating types. This study takes advantage of 3-D direct numerical simulations of fluid flow combined with real life, and full scale measurements of flow and swell noise acquired on purpose built seismic streamer cables in the ocean, to study the mechanisms responsible for flow noise generation. The combined knowledge obtained by the simulations and the measurements are then put to use in order to come up with practical methods to reduce noise in seismic data. Two different paths are followed: The first is in the form of a software de-noising algorithm developed and implemented as a module in a commercial seismic processing software package. It works in the frequency domain by statistically comparing neighboring traces, and attenuates amplitudes that are found to be abnormal. The module is in daily use, and has successfully been applied to attenuate various types of noise found in both land, and marine seismic data. The second path followed to reduce the amount of noise in seismic data is to use so-called superhydrophobic surfaces. This is in the form of a coating material that can be applied to seismic streamers to reduce both drag and flow noise. The flow noise reduction capabilities of superhydrophobic surfaces is a new discovery, which holds great promise

Technical approaches, chapter 3, part E

Radar altimeters, scatterometers, and imaging radar are described in terms of their functions, future developments, constraints, and applications

The environment,diversity and activity of microbial communities in submarine freshwater springs in the Dead Sea

The Dead Sea, located at the border between Jordan, Israel and the Palestinian authority is one of the most hypersaline lakes on earth. Its waters contain a total dissolved salt concentration of up to 348 g L-1, which is about 10 times higher than regular sea water. The lake is characterized by elevated concentrations of divalent cations (~2 M Mg2 and ~0.5 M Ca2 ), which, in addition to the high salinity, form an extreme environment where only highly adapted microorganisms can survive. This doctoral thesis describes the environment, diversity and activity of microbial communities in a novel ecosystem of submarine freshwater springs in the Dead Sea. These springs allow for the formation of diverse microbial mats in an otherwise hostile environment. Water chemistry analysis showed that these springs originate from the Judean Group Aquifer. However, their chemistry is altered along the subsurface flow path from the Aquifer to the Dead Sea due to microbial activity, mixing with interstitial brine in the sediment and dissolution and precipitation of minerals. Pyrosequencing of the 16S rRNA gene and community fingerprinting methods revealed that most of the spring sediment community originates from the Dead Sea sediments and not from the spring water. Using a novel salinity mini-sensor and a flume system that simulates the spring water flow into the Dead Sea it was demonstrated in the second study, that microenvironments of reduced salinity are formed in sediments and around rocks in the springs. The presence of microbial mats in these unique microenvironments led to the conclusion that one of the main drivers of the abundant microbial life is a local salinity reduction. However, as shown by flow and salinity microsensor measurements, the locally decreased salinity is unstable due to frequent fluctuations in the spring water flow. Therefore, although the microorganisms inhabiting these environments are exposed to an overall reduced salinity, they have to cope with large and rapid salinity fluctuations in the range of minutes to hours. The results of the third study showed that some of the microbial mats found in the spring area are either dominated by diatoms or unicellular cyanobacteria and are spatially separated. Growth experiments showed that the local salinity reduction is sufficient to allow for growth of these phototrophs, however, the salinity fluctuations directly affect their distribution. This could be deduced from the observation that diatoms and cyanobacteria had different in-vitro recovery rates of photosynthetic activity following rapid salinity shifts. Furthermore, the high energy demand which is expected to result from the salinity fluctuations, limits phototrophic life to shallow water depths, where enough light is available, in this case less than 10 meters. As shown in the fourth study, other microbial mats in the spring ecosystems were dominated by sulfide oxidizing bacteria (SOB), which were fueled by a flux of sulfide from the sediment below. However, sulfate reduction rates (SRR) in the spring surface sediment (<2.8 nmol cm3 day-1), were too low to account for the sulfide flux determined by in situ microsensor measurements. In fact, isotopic analysis of coexisting sulfide and sulfate in the spring water showed that the reduced sulfur compounds are instead produced along the flow path. The sulfide flux, in combination with a locally reduced salinity and O2 supply from the Dead Sea water column are the driving factors for the abundant microbial biomass of SOB encountered in the springs. Microbial mats in the Dead Sea are dominated by different types of microorganisms, ranging from different SOB genera, to cyanobacteria or diatoms. Differences in the availability of light, the mean salinity and the scale of salinity fluctuations at different spots are the main factors determining the dominating community and their spatial distribution. As reduced salinity in the spring ecosystems was shown to play an extremely important role in supporting life, it was surprising to discover that SRR in the Dead Sea sediment were higher than in the less-saline springs (up to 10 nmol cm3 day-1). While this indicates the presence of an unexpectedly active, extremely halophilic community of sulfate reducing bacteria (SRB) in the Dead Sea sediments, it also suggests that the extensive salinity fluctuations within the springs may limit the SRB populations due to the high energetic cost of osmoregulation in the dynamic system. Therefore while this thesis shows that the low salinity environment of the Dead Sea springs is advantageous for microbial life, the fluctuations within the environment bring their own set of challenges

Aqueous Turbulence Structure Immediately Adjacent to the Air - Water Interface and Interfacial Gas Exchange

Air-sea interaction and the interfacial exchange of gas across the air-water interface are of great importance in coupled atmospheric-oceanic environmental systems. Aqueous turbulence structure immediately adjacent to the air-water interface is the combined result of wind, surface waves, currents and other environmental forces and plays a key role in energy budgets, gas fluxes and hence the global climate system. However, the quantification of turbulence structure sufficiently close to the air-water interface is extremely difficult. The physical relationship between interfacial gas exchange and near surface turbulence remains insufficiently investigated. This dissertation aims to measure turbulence in situ in a complex environmental forcing system on Lake Michigan and to reveal the relationship between turbulent statistics and the CO2 flux across the air-water interface. The major objective of this dissertation is to investigate the physical control of the interfacial gas exchange and to provide a universal parameterization of gas transfer velocity from environmental factors, as well as to propose a mechanistic model for the global CO2 flux that can be applied in three dimensional climate-ocean models. Firstly, this dissertation presents an advanced measurement instrument, an in situ free floating Particle Image Velocimetry (FPIV) system, designed and developed to investigate the small scale turbulence structure immediately below the air-water interface. Description of hardware components, design of the system, measurement theory, data analysis procedure and estimation of measurement error were provided. Secondly, with the FPIV system, statistics of small scale turbulence immediately below the air-water interface were investigated under a variety of environmental conditions. One dimensional wave-number spectrum and structure function sufficiently close to the water surface were examined. The vertical profiles of turbulent dissipation rate were intensively studied. Comparison between the turbulence structures measured during the wind wave initiation period and those obtained during the growing period was presented. Significant wave effects on near surface turbulence were found. A universal scaling law was proposed to parameterize turbulent dissipation rate immediately below the air-water interface with friction velocity, significant wave height and wave age. Finally, the gas transfer velocity was measured with a floating chamber (FC) system, along with simultaneously FPIV measurements. Turbulent dissipation rate both at the interface and at a short distance away from the interface (~ 10 cm) were analyzed and used to examine the small scale eddy model. The model coefficient was found to be dependent on the level of turbulence, instead of being a constant. An empirical relationship between the model coefficient and turbulent dissipation rate was provided, which improved the accuracy of the gas transfer velocity estimation by more than 100% for data acquired. Other data from the literature also supported this empirical relation. Furthermore, the relationship between model coefficient and turbulent Reynolds number was also investigated. In addition to physical control of gas exchange, the disturbance on near surface hydrodynamics by the FC was also discussed. Turbulent dissipation rates are enhanced at the short distance away from the interface, while the surface dissipation rates do not change significantly