Water transparency measurements in the deep Ionian Sea

Anassontzis, E.G.; Ball, A.E.; Belias, A.; Fotiou, A.; Grammatikakis, G.; Kontogiannis, H.; Koske, P.; Koutsoukos, S.; Lykoussis, V.; Markopoulos, Evangelos; Psallidas, A.; Resvanis, L. K.; Siotis, I.; Stavrakakis, S.; Stavropoulos, G.; Жуков, В.

doi:10.1016/j.astropartphys.2010.06.008

Cited by 14 publications

(7 citation statements)

References 8 publications

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“…Light reactions in humic-rich freshwaters are avoided to al arge extent since they contain as ignificantly higher concentration of light absorbing substances compared to oceanic waters. [27] Thus,o xidation state and coordination geometry remain unchanged for the majority of Fe-HS complexes (octahedral Fe III O 6 ;F igure 1) during transport from freshwaters to open oceans,d espite their vastly varying Table S5 (Supporting Information). The inset in (d) and (e) show the k-space data of CB0 13 with the corresponding fit.…”

Section: Angewandte Chemiementioning

confidence: 99%

Photoreduction of Terrigenous Fe‐Humic Substances Leads to Bioavailable Iron in Oceans

et al. 2016

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Humic substances (HS) are important iron chelators responsible for the transport of iron from freshwater systems to the open sea, where iron is essential for marine organisms. Evidence suggests that iron complexed to HS comprises the bulk of the iron ligand pool in near‐coastal waters and shelf seas. River‐derived HS have been investigated to study their transport to, and dwell in oceanic waters. A library of iron model compounds and river‐derived Fe‐HS samples were probed in a combined X‐ray absorption spectroscopy (XAS) and valence‐to‐core X‐ray emission spectroscopy (VtC‐XES) study at the Fe K‐edge. The analyses performed revealed that iron complexation in HS samples is only dependent on oxygen‐containing HS functional groups, such as carboxyl and phenol. The photoreduction mechanism of FeIII‐HS in oceanic conditions into bioavailable aquatic FeII forms, highlights the importance of river‐derived HS as an iron source for marine organisms. Consequently, such mechanisms are a vital component of the upper‐ocean iron biogeochemistry cycle.

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Section: Angewandte Chemiementioning

confidence: 99%

Photoreduction of Terrigenous Fe‐Humic Substances Leads to Bioavailable Iron in Oceans

et al. 2016

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“…This method uses algorithms which evaluate the brightness value of red and blue band taken from the images to predict the ZSD [42][43][44]. Long Arm Marine Spectrophotometer (LAMS) is a device that measures water clarity by light transmission in deep water [45]. Lidar systems use signal decay rate to estimate water optical quality [46].…”

Section: Introductionmentioning

confidence: 99%

Development of a Solar-Powered IoT-Based Instrument for Automatic Measurement of Water Clarity

Pham

Nguyen

et al. 2020

Sensors

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Water clarity is the most common indicator of water quality. The purpose of the study was to develop an instrument which can automatically measure water clarity in place of manual measurement by Secchi disk. The instrument is suspended by buoys at the water surface and uses solar energy to measure the light intensity of LED bulbs after passing through a water column; the result is then converted to Secchi depth by using a regression function. Measurement data are stored in a cloud server so that mobile users can access via an Internet connection. Three experiments were conducted to examine the instrument performance: (i) to ensure light intensity of the LED bulbs is strong enough to pass through the water column; (ii) to determine the regression relationship between the measured light intensity of the instrument and Secchi depth; and (iii) to evaluate the coefficient of variation (CV) of the measured water clarity when using our instrument and a conventional Secchi disk. Experiment results show that the measured values of light intensity are stable with the average CV = 5.25%. Moreover, although there are slight differences between the Secchi depth measured by our instrument and those measured by Secchi disk, the measurements by our instrument can efficiently replace the measurements by conventional Secchi disk, which can be affected by weather conditions as well as by human subjectivity.

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“…Pylos site has ideal water 09004-p. 4 Very Large Volume Neutrino Telescope (VLVnT-2015) properties for neutrino detection experiments, i.e. low velocity currents, low bioluminescence and low rate of sedimentation [6]. The prototype is deployed at a depth of 2960 m and the coordinates are lat: 36 • 50.012 and long: 21 • 30.003 , and it will be retrieved shortly after the six month operational period.…”

Section: Deploymentmentioning

confidence: 99%

GRBNeT – A prototype for an autonomous underwater neutrino detector

Pikounis

Markou

Anassontzis

et al. 2016

EPJ Web of Conferences

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Abstract.GRBNeT is a project aiming at the detection of ultra-high energy neutrinos, for example neutrinos originating from Gamma Ray Bursts. The goal is to design, construct and deploy a prototype unit of an autonomous (data/energy-wise) neutrino detector. Being autonomous is crucial since for the detection of ultra-high energy neutrinos a very large volume of water is required. Large scale facilities such as IceCube and KM3NeT are designed to be more sensitive to galactic and diffuse flux neutrinos rather than extragalactic ultra-high energy neutrinos. However, their sensitivity to such neutrinos could be increased by placing around and at larger distances detectors such as the one of the GRBNeT project. This extension would increase the instrumented volume of neutrino telescopes to several cubic kilometres. In addition to that, as no cable connection to the shore is required, GRBNeT detection units cost significantly less than regular detection units and can become a cost effective extension of large scale facilities. For the GRBNeT prototype unit ultra low power electronics have been developed. The response to high energy neutrinos from GRBs and to the atmospheric muon background has been simulated.

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Water transparency measurements in the deep Ionian Sea

Cited by 14 publications

References 8 publications

Photoreduction of Terrigenous Fe‐Humic Substances Leads to Bioavailable Iron in Oceans

Photoreduction of Terrigenous Fe‐Humic Substances Leads to Bioavailable Iron in Oceans

Development of a Solar-Powered IoT-Based Instrument for Automatic Measurement of Water Clarity

GRBNeT – A prototype for an autonomous underwater neutrino detector

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