Separate Stations Research Articles

Distribution and diversity of elasmobranchs in the Sea of Marmara: A 2023 status report

Abstract Elasmobranchs, encompassing an array of sharks and rays, confront a threat of extinction on a global scale. The Sea of Marmara (SoM) stands out as a critical refuge for these endangered species. This study harnesses data derived from comprehensive trawl surveys, representing the first area‐based evaluation of the elasmobranchs inhabiting the SoM. Sampling protocols were carried out at 10 separate stations along the 980‐km coastline of the SoM, each bounded by different ecological characteristics and anthropogenic influences. A total of eight shark species and six ray species were caught in the towed area of the entire the SoM. Notably, Scyliorhinus canicula and near‐threatened Raja clavata constitute more than 50% of the total abundance. Additionally, rare, and critically endangered species, including the Oxynotus centrina, Squatina squatina, Dipturus batis, and Myliobatis aquila, were documented, expanding our knowledge of their presence in the region. Spatial distribution heterogeneity was pronounced within species. Size distributions were species‐specific, and the presence of both juvenile and adult individuals suggested successful reproduction and growth. Records expand the known size range in the SoM for six shark and three ray species. It also provides first‐size information based on the total length of the S. stellaris and D. batis. Additionally, the urgent need for field‐based conservation efforts is highlighted, citing a previously unidentified important sensitive areas located in the southern part of the SoM.

Distribution and influencing factors of macrobenthos on three seagrass beds in the intertidal zone of Shandong province, China

IntroductionThe macrobenthos plays a vital role within the ecosystem of seagrass beds, with its characteristics and spatial distribution serving as indicators of the well-being of the seagrass beds.MethodsIn August 2018, three seagrass beds located in the Yellow River Estuary of Dongying, the west coast of Yantai, and Swan Lake of Weihai, were investigated to compare the ecological influences of seagrass habitat on the benthic environment and macrobenthic community. Within each seagrass bed, porewater, sediment, and macrobenthos were sampled from three separate stations (center of seagrass bed, edge of seagrass bed and bare area).Results and discussionOne-way ANOVA showed significant differences (p < 0.05) in environmental factors and macrobenthos species, abundance, biomass and diversity indices among the three seagrass beds. The present data did not show significant impacts on habitat and macrobenthos in the different coverage areas of seagrass beds at the investigated spatial scales, though crustacea and some carnivores were relatively more inclined to inhabit areas with higher seagrass densities. Aquaculture and eutrophication may trigger the loss of seagrass bed habitats, that affects macrobenthic biodiversity, and conservation measures are needed to protect seagrass bed habitats.

METHOD FOR AGENT-ORIENTED TRAFFIC PREDICTION UNDER DATA AND RESOURCE CONSTRAINTS

Context. Problem of traffic prediction in a city is closely connected to the tasks of transportations in a city as well as air pollution detection in a city. Modern prediction models have redundant complexity when used for separate stations, require large number of measuring stations, long measurement period when predictions are made hourly. Therefore, there is a lack of method to overcome these constraints. The object of the study is a city traffic.
 Objective. The objective of the study is to develop a method for traffic prediction, providing models for traffic quantification at measuring stations in the future under data and resource constraints.
 Method. The method for agent-oriented traffic prediction under data and resource constraints was proposed in the paper. This method uses biLSTM models with input features, including traffic data obtained from agent, representing target station, and other agents, representing informative city stations. These agents are selected by ensembles of decision trees using Random Forest method. Input time period length is proposed to set using autocorrelation data.
 Results. Experimental investigation was conducted on traffic data taken in Madrid from 59 measuring stations. Models created by the proposed method had higher prediction accuracy with lower values of MSE, MAE, RMSE and higher informativeness compared to base LSTM models.
 Conclusions. Obtained models as study results have optimal number of input features compared to the known models, do not require complete system of city stations for all roads. It enables to apply these models under city traffic data and resource constraints. The proposed solutions provide high informativeness of obtained models with practically applicable accuracy level.

Reconciling results of 2019 and 2020 stellar occultations on Pluto’s atmosphere

A stellar occultation by Pluto on 5 September 2019 yielded positive detections at two separate stations. Using an approach consistent with comparable studies, we derived a surface pressure of 11.478 ± 0.55 µbar for Pluto’s atmosphere from the observations of this event. In addition, to avoid potential method inconsistencies when comparing with historical pressure measurements, we reanalyzed the data for the 15 August 2018 and 17 July 2019 events. All the new measurements provide a bridge between the two different perspectives on the pressure variation since 2015: a rapid pressure drop from previous studies of the 15 August 2018 and 17 July 2019 events and a plateau phase from that of the 6 June 2020 event. The pressure measurement from the 5 September 2019 event aligns with those from 2016, 2018, and 2020, supporting the latter perspective. While the measurements from the 4 June 2011 and 17 July 2019 events suggest probable V-shaped pressure variations that are unaccounted for by the volatile transport model (VTM), the VTM remains applicable on average. Furthermore, the validity of the V-shaped variations is debatable given the stellar faintness of the 4 June 2011 event and the grazing single-chord geometry of the 17 July 2019 event. To reveal and understand all of the significant pressure variations of Pluto’s atmosphere, it is essential to provide constraints on both the short-term and long-term evolution of the interacting atmosphere and surface by continuous pressure monitoring through occultation observations whenever possible, and to complement these with frequent spectroscopy and photometry of the surface.

COMBINING STRUCTURED LIGHT SCANNING AND 3D PRINTING TO PRODUCE PHYSICAL MODELS OF HUMAN BONES: A PILOT STUDY

While the COVID-19 pandemic highlighted the need for more accessible anatomy instruction tools, it is also well known that the time allocated to practical anatomy teaching has reduced in the past decades. Notably, the opportunity for anatomy students to learn osteology is not prioritised, nor is the ability of students to appreciate osteological variation. As a potential method of increasing accessibility to bone models, this study describes the process of developing 3D-printed replicas of human bones using a combination of structured light scanning (SLS) technology and 3D printing.Human bones were obtained from the Anatomy Lab at the University of Edinburgh and were digitised using SLS via an Einscan H scanner. The resulting data was then used to print multiple replicas of varying materials, colours, scales and resolutions on an Ultimaker S3 3D printer. To gather opinion on these models and their variables, surveys were completed by anatomy students and educators (n=57). Data was collected using a Likert scale response, as well as free-text answers to gather qualitative information.3D scans of the scapula, atlas (C1 vertebrae) and femur were successfully obtained. Plastic replicas were produced with defined variables in 4 separate stations e.g. different colours, to obtain results from survey respondents. For colour, 87.7% of survey respondents preferred white models, with 7% preferring orange and 5.3% preferring blue. For material, 47.4% of respondents preferred PLA (Polylactic acid), while 33.3% preferred ABS (Acrylonitrile butadiene styrene), 12.3% preferred Pet-G (Polyethylene terephthalate glycol), 3.5% preferred Glassbend and 3.5% had no preference. Additional results based on scale and resolution were also collected.This initial study has demonstrated a proof-of-concept workflow for SLS technology to be combined with 3D printing to produce plastic replicas of human bones. Our study has provided key information about the colour, scale, material and resolution required for these models. Our future work will focus on determining accuracy of the models and their use as teaching aids for osteology education.

Deep learning mapping of surface MDA8 ozone: The impact of predictor variables on ozone levels over the contiguous United States

The limited number of ozone monitoring stations imposes uncertainty in various applications, calling for accurate approaches to capturing ozone values in all regions, particularly those with no in-situ measurements. This study uses deep learning (DL) to accurately estimate daily maximum 8-hr average (MDA8) ozone and examines the spatial contribution of several factors on ozone levels over the contiguous U.S. (CONUS) in 2019. A comparison between in-situ observations and DL-estimated MDA8 ozone values shows a correlation coefficient (R) of 0.95, an index of agreement (IOA) of 0.97, and a mean absolute bias (MAB) of 2.79 ppb, highlighting the promising performance of the deep convolutional neural network (Deep-CNN) at estimating surface MDA8 ozone. Spatial cross-validation also confirms the high spatial accuracy of the model, which obtains an R of 0.91, and IOA of 0.96 and an MAB of 3.46 ppb when it is trained and tested on separate stations. To interpret the black-box nature of our DL model, we use Shapley additive explanations (SHAP) to generate a spatial feature contribution map (SFCM), the results of which confirm an advanced ability of Deep-CNN to capture the interactions between most predictor variables and ozone. For instance, the model shows that solar radiation (SRad) SFCM, with higher values, enhances the formation of ozone, particularly in the south and southwestern CONUS. As SRad triggers ozone precursors to produce ozone via photochemical reactions, it increases ozone concentrations. The model also shows that humidity, with its low values, increases ozone concentrations in the western mountainous regions. The negative correlation between humidity and ozone levels can be attributed to factors such as higher ozone decomposition resulting from increased levels of humidity and OH radicals. This study is the first to introduce the SFCM to investigate the spatial role of predictor variables on changes in estimated MDA8 ozone levels.

A significant wave height prediction method based on deep learning combining the correlation between wind and wind waves

Accurate wave height prediction is significant in ports, energy, fisheries, and other offshore operations. In this study, a regional significant wave height prediction model with a high spatial and temporal resolution is proposed based on the ConvLSTM algorithm. The model learns the intrinsic correlations of the data generated by the numerical model, making it possible to combine the correlations between wind and wind waves to improve the predictions. In addition, this study also optimizes the long-term prediction ability of the model through the proposed Mask method and Replace mechanism. The experimental results show that the introduction of the wind field can significantly improve the significant wave height prediction results. The research on the prediction effect of the entire study area and two separate stations shows that the prediction performance of the proposed model is better than the existing methods. The model makes full use of the physical correlation between wind and wind waves, and the validity is up to 24 hours. The 24-hour forecast R² reached 0.69.

Evaluating the Efficacy of Five Chlorophyll-a Algorithms in Chesapeake Bay (USA) for Operational Monitoring and Assessment

This manuscript describes methods for evaluating the efficacy of five satellite-based Chlorophyll-a algorithms in Chesapeake Bay, spanning three separate sensors: Ocean Land Color Imager (OLCI), Visible Infrared Imaging Radiometer Suite (VIIRS), and MODerate Resolution Imaging Spectroradiometer (MODIS). The algorithms were compared using in situ Chlorophyll-a measurements from 38 separate stations, provided through the Chesapeake Bay Program (CBP). These stations span nearly the entire 300 km length of the optically complex Chesapeake Bay, the largest estuary in the United States. Overall accuracy was examined for the entire dataset, in addition to assessing the differences related to the distance from the turbidity maximum to the north by grouping the results into the upper bay, middle bay, or lower bay. The mean bias and the Mean Absolute Error (MAE) as well as the median bias and Median Absolute Error (MedAE) were conducted for comparison. A two-band algorithm, that is based on the red-edge portion of the electromagnetic spectrum (RE10), when applied to OLCI imagery, exhibited the lowest overall MedAE of 36% at all stations. As a result, it is recommended that the RE10 algorithm be applied to OLCI and provided as an operational product through NOAA’s CoastWatch program. The paper will conclude with results from a brief climatological analysis using the OLCI RE10 algorithm.

First Demonstration of Single-Pass Distributed SAR Tomographic Imaging With a P-Band UAV SAR Prototype

A distributed configuration is a promising realization of tomographic synthetic aperture radar (TomoSAR) 3-D imaging. It is able to implement single-pass tomographic imaging in a very short time and, hence, outperforms the traditional time-consuming multipass TomoSAR. It also outperforms the traditional single-platform TomoSAR by achieving a higher resolution in elevation by forming a much larger spatial baseline. However, there has been little research reported on the distributed TomoSAR so far. In this article, we, for the first time, experimentally demonstrate the great potential of the single-pass distributed TomoSAR 3-D imaging. The main contributions are threefold. First, a new distributed TomoSAR 3-D imaging model is built, characterized by using both inner monostatic and bistatic spatial configurations. Second, a new multistatic synchronization scheme is developed for accurately correcting both multistatic time and phase synchronization errors. Finally, a P-band distributed unmanned-aerial-vehicle (UAV) TomoSAR prototype with four separate stations is built with an elaborately designed time-division waveform for full data acquisition. To the best of our knowledge, this is the first distributed TomoSAR system. We have also implemented the first single-pass TomoSAR 3-D imaging experiment and successfully achieved a meter-level 3-D image in Pinggu, Beijing, China.

A pilot project to introduce the multiple mini interview (MMI) at a Borneo medical school: The universiti Malaysia Sabah experience- a cross-sectional study

IntroductionThe Multiple Mini Interview (MMI) demonstrates efficacy and superiority over traditional medical interviews in assessing non-cognitive domains during the recruitment of medical undergraduates. At Universiti Malaysia Sabah (UMS), a five-station MMI was piloted in 2019, featuring a mix of three examiner-driven stations (assessing professionalism, ethics, and motivation to study medicine), and two roleplayer-driven stations (assessing empathy and science communication specifically, and communication skills in general). Methods260 candidates were grouped into two separate geographical groups – urban and suburban/rural. Descriptive analysis, skewness and kurtosis were performed for normality assessment, whereas Cronbach's alpha, McDonald's omega, and Greatest lower bound assessed internal consistency. For validity measures, correlations were calculated between scores for separate stations, overall scores, urban and suburban/rural status. Also, exploratory factor analysis was performed on the five stations as validity measures. Difficulty and discrimination indices were calculated as quality measures. Qualitative analysis was performed on “red flag” comments detailing grossly unsuitable candidates. ResultsRoleplayer-driven stations yielded more red flags than examiner-driven stations. The three examiner-driven stations were significantly and moderately correlated (rho between 0.602 and 0.609, p < 0.001). The Empathy roleplayer-driven station was not correlated with two examiner-driven stations and only weakly correlated with the Ethics examiner-driven and the Science Communication roleplayer-driven station. Factor analysis suggests a three-factor model. The two roleplayer-driven stations stood as independent factors, and the three examiner-driven stations coalescing as one factor provided the best explanatory model. Quality measures suggest all five stations had suitable discriminatory properties (all >0.530), whereas the stations were distributed equally in difficulty index. ConclusionThe UMS MMI has identified specific skillsets that may be in short supply in our incoming medical students. Also, it illustrates the yawning gap between academic knowledge and ‘translational’ scientific knowledge and communication skills.

Levels, bioaccumulation and biomagnification of pesticide residues in a tropical freshwater food web

The study assessed pesticide contamination transfer in Ikpoba River, an important tropical freshwater ecosystem in Southern Nigeria. The study quantified concentrations, bioaccumulation and biomagnification of pesticides in Ikpoba River’s food web, with emphasis on less frequently assessed lower trophic-level organisms. Concentrations of pesticides were quantified in water, sediment and biota (phytoplankton, green algae (Cladophora), macrophyte (Commelina erecta), macrobenthic invertebrates (Lestes species, Caridina africana, Enallagma species, Gerris lacustris, Culex species, Pentaneura species, Sympetrum species, Argyroneta aquatica, Lecane species (Cladocera) and pelagic fish (Tilapia zilli)). Samples were collected at two separate stations and were analyzed using gas chromatography equipped with electron capture detector. Aldrin was the dominant pesticide in the Ikpoba River food web with concentrations accounting for 14.4% of the total pesticide residues in the assessed matrices. Sediment samples had significantly higher pesticide concentrations among the matrices assessed, with a total mean concentration of 0.095 ± 0.02 µg/kg dw. Among the biota samples, total pesticide levels were significantly higher (p < 0.05) in Commelina erecta. BAF and BSAF values were also highest in this species indicating that Commelina erecta may represent a greater reservoir for pesticides and may be a principal factor in subsequent transfer of pesticides along the food web of Ikpoba River. The BMF values for α-HCH, γ-HCH, β-HCH, glyphosate, heptachlor, aldrin, heptachlor epoxide, endosulfan I, endrin, carbofuran and diazinon showed that these pesticides have the potential to biomagnify along the trophic levels. The persistence of these pesticides in Ikpoba River supports the need for continuous monitoring.

Spatial variations of coda-wave attenuation in the Khurgu region, south-east of the Zagros from analysis of local earthquakes

In this study, we estimate the characteristics of coda-wave attenuation in the Khurgu region, southeast of Zagros, with the use of single-back scattering procedure. The selected database comprises of 4870 seismograms of 259 local earthquakes recorded from March to June 2006, at 25 seismic stations within 2–100 km of epicentral distance, depth range 4–25 km, and 2–4.7 local magnitude range. oda attenuation analyzed on narrow bandpass-filtered seismograms from the time-domain decay of coda-wave amplitudes. The intended frequency-band ranged from 0.5 to 24.0 Hz.Moreover, coda Q values have been estimated by using different window length, from 5 to 50 s. The coda Q value shows frequency decency in the form of Qof n.The mean-frequency relation for the above region has been found to be Qc = 29 ± 1.0f 1.13±0.007 for the 5-sec lapse-time window length as well as Qc = 147 ± 1.4f 0.99 ±0.045 for the 50 s lapse time window length.The Qc value has been estimated at 25 stations and its lateral variation has been analyzed in this study. The distinct Coda Q values were observed at separate stations between the southern and northern regions. Our observations showed major differences in the coda depth. In addition, Coda Q values in the northern part are lower than southern part at all depths.Beneath south and north of High Zagros Fault (HZF), the increase rate of Qc has been higher at the depth 70 and 80 km, respectively. This may indicate the presence of the increased attenuation anomaly beneath the area lithosphere.

EVALUATING FOCAL MECHANISM OF SEPTEMBER 24, 2013 AWARAN EARTHQUAKE WITH GEOSPATIAL TECHNIQUES

Seismic records from IRIS (NIL, KBL, MSEY, KMI, QIZ, DGAR) were used to compute AWARAN September 24 2013 Earthquake's focal mechanism. Earthquakes are one of the most drastic threats that are likely to cause heavy human casualties and can destroy entire cities within minutes. We processed the waveform data from 6 separate stations for the computation of displacement. The issues related to attenuation have been overcome by the use of low frequencies (0.05-0.1). The crustacean model that determines the tensor PREM model's time is determined by minimizing the variance but produces a robust focal mechanism. Inverting the displacement data is applied to recover the moment tensor from the source, calculated the green feature with the reversal. GIS-based vectors of fault lines were abstracted by the digitization of regional tectonic lineaments and structural maps. We developed synthetic and observed surface shapes with a 100 percent dc correlation. Our understanding of the features of crustacean deformation and regional tectonics in the area will benefit from the resulting focus mechanisms. The measured earthquake focal mechanism is similar to a USGS agency hit, dip, and rake.

Velocity‐Based Earthquake Detection Using Downhole Distributed Acoustic Sensing—Examples from the San Andreas Fault Observatory at Depth

AbstractConventional seismographic networks sparsely sample the wavefields excited by earthquakes. Thus, standard event detection is conducted by analyzing separate stations and merging their results. Emerging distributed acoustic sensing recording technologies allow for unbiased spatial sampling of the wavefield and, as a result, array‐based processing of the recorded signals. Using a cemented fiber in the San Andreas Fault Observatory at Depth main hole, 800 virtual receivers are sampled at a 1 m interval from the surface to 800 m depth. Recorded earthquakes are approximated as plane waves reaching the bottom of the array first. Following this assumption, the relative travel times of the recorded event depend on the local velocity at the array location and the angle of incidence at which the planar wavefront reaches it. Given the seismic velocity, a newly proposed detection algorithm amounts to a single‐parameter scan of the incidence angle and measurement of data coherency along the different possible travel‐time curves. Using the entire recording array, a much higher effective signal‐to‐noise ratio can be obtained when compared to individual channel processing. About 20 days of recorded seismic activity from the San Andreas Fault is analyzed. Using a downhole single array, the majority of cataloged events in the area are detected. In addition, a previously unknown event is unveiled. We estimate its magnitude at roughly −0.5.

Methane and sulfide sulfur in the bottom sediments of lake Baikal

The paper analyzes data on the distribution of methane and sulfide sulfur concentrations in the upper layer of the bottom sediments in different areas of Lake Baikal obtained during expeditions in 2014 and 2015. During the study, concentrations of methane and sulfide sulfur in lake sediments varied from &lt;0.01 to 3.69 μg/g dry sediment (mean 0.34 μg/g) and from 0.002 to 0.830 mg/g dry sediment (mean 0.042 mg/g), respectively. The maximum concentrations of methane were typical of the Northern region, where the waters of the Upper Angara, Kichera rivers flow, and separate stations of profile along the estuary zone of the Selenga River, as well as stations located in the zone of underwater wastewater discharge of Baikalsk and the Baikal pulp and paper mill closed in 2013. A comparison of the distribution of methane and sulfide sulfur concentrations indicates an intense sulfate reduction at the stations with the highest methane concentrations, which suggests the conjugate processes of their generation. Variations of methane and sulfide sulfur concentrations in the studied upper layers of Lake Baikal sediments are caused by the differences in the anthropogenic impact and also by the variability of sedimentation conditions that determine the grain size composition and the content of organic matter, and, as a consequence, the intensity of methanogenesis and sulfate reduction.

Evaluation of MODIS land surface temperature products for daily air surface temperature estimation in northwest Vietnam

ABSTRACT Recently, the MODerate resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) is considered one of the most suitable ways to retrieve air surface temperature (T a) – one of the most important and widely used climate variables for a wide range of applications. In fact, many successful studies have been reported in many regions of the world. Each day, four MODIS LST data are available; from two sensors (Terra and Aqua) at two local overpass times (daytime and night-time). However, due to their different overpass times, most studies have used LST daytime and night-time for daily maximum (T max) and minimum (T min) air surface temperature estimation, respectively. Therefore, the performance of each individual LST data, the effect of the dynamic combination of these four LST data, the effect of land surface characteristics, and the effect of LST quality on the same estimation in the same region on the accuracy of estimated T a remains unclear. In this study, we evaluated and tested all individual LST data as well as all possible combinations of the four MODIS LST data from two separate stations with distinct land surface characteristics in northwest Vietnam for 10 years (from 2004 to 2013) under two sky conditions (all clear sky conditions and only good data – i.e. Quality Control (QC) value of 0) for daily T a (T max, T min, and T mean) estimations. In addition, the mixed data of the two stations were also evaluated. Our results showed that Terra LST data have a higher correlation with T a than Aqua LST; which is consistent for both stations and both quality conditions (all clear sky and only good data). A closer overpass time with T max or T min occurrence time did not guarantee a higher accuracy of T a estimation. Using only good LST data produced a higher accuracy of T a estimation than using all clear sky data. However, if the percentage of good data is low (i.e. less than 30%), then the all clear sky data will provide better results for T max estimation. Comparing the performance of the different combinations when using the single station and mixed station data, combinations including at least one night-time LST produced stable and high accuracy T min and T mean estimates, while the combinations with only daytime LST produced very low accuracy results. For T max estimation, the results were less impacted by LST quality; however, they were strongly impacted by different combinations and land surface characteristics.

Analysis of inverter non‐linearity influence on modulation technique selection in a dual three‐phase induction machine drives

This study aims to investigate the correlation between inverter non-linearity and modulation technique selection in a dual three-phase induction machine (D3IM) drives. Even though vector space decomposition (VSD) technique is in the literature perceived as the most suited and well-adapted control strategy for D3IM, herein conducted analysis has established that VSD vector selection principle together with inverter non-linearity effects can lead to a significant decrease in the performance of a driven machine. It is demonstrated that by changing vector selection principle, the influence of the mentioned inverter limitations could be reduced without any major negative influence on other important aspects that determine technique suitability for the use in D3IM drives. The experimental results gathered from two separate test stations undoubtedly show the mutual impact of the inverter non-linearity and vector selection strategy on the drive overall performance.

A Study on Lightweight Cryptography Algorithm for IoT based Bicycle Sharing System

In this paper, we studied lightweight cryptography for IoT based Bicycle Sharing System. We maintained a remotely located real time server and four separate stations with kiosk control box system, designed with Internet based IoT devices. Then, we calculated the processing time to unlock the bicycle from each station, once the request was sent to the server. The calculated load and processing time were compared after the application of cryptography algorithm. The comparison helped us conclude that the LEA cryptography showed minimal time difference when applied in a real time system. At the same time, highly secure data transmission was also achieved.

Phase Comparison Method for Wide-Frequency-Range Microwave Photonic Signals

The goal of this study is to establish a phase comparison method using high-frequency microwave photonic signals. The signal is generated as a beat frequency of a dual-wavelength optical signal. We propose a double differential phase comparison method suitable for a phase-locked loop. This is achieved by using an optical frequency shifter and two low-frequency photomixers (optical-to-electrical signal converters). The basic approach of the method is that the phase difference between the high-frequency dual-wavelength signals can be measured as a differential phase of the detected low-frequency microwave signals by two respective low-frequency photomixers without high-frequency photomixers. With this approach, the phase comparison of any range of frequencies of the dual-wavelength signals can be performed by two identical low-frequency photomixers. In an application of this method for separate fiber-coupled stations, a common laser signal transmission is effectively carried out with a dual-wavelength optical signal. We conducted an experiment to verify the effectiveness of the double differential phase comparison method by comparing the direct phase comparison method.

A multi disciplinary overview of factors controlling on meiofauna assemblages around Maden and Alibey islands in Ayvalik (Balikesir, Eastern Aegean Sea)

In coastal parts of the study areas, heavy metals containing ground water flows along the faults and fractures and reaches at sea. In these contaminated waters, morphologically abnormal individuals of the affected meiofauna (benthic foraminifera, ostracod, mollusc) can be found. Three cores were taken from the seafloor in the four separate stations that are located in NW of Ayvalık village, around Alibey and Maden islands, and one core of each three core groups was studied in order to investigate the aforementioned morphological affects on the recent meiofauna, which have been inhibited in those contaminated waters. Lead, manganese, hematite and limonite deposits with small reserves were present in Alibey, Maden and Küçük (Small) Maden islands. Morphological changes and coloring were observed in tests of large number of Peneroplis, Lobatula, Ammonia and Elphidium samples collected from these areas. This observation vindicates impact of heavy metals onto the foraminifera assemblages. Heavy metals and other chemical and radioactive elements found in the surrounding country side have been naturally transported into the adjacent sea water during the past and present. The aim of this study is to figure out the effects of the chemical and radioactive elements, which were carried from the land on the meiofaunal (benthic foraminifera, ostracod and mollusc) assemblages.