Journal articles: 'Light in sea-water'

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Meutia, Eva, Upik Nurbaiti, and Fianti Fianti. "PENGARUH RADIASI MATAHARI PADA AIR LAUT TERHADAP DAYA YANG DIHASILKAN SEBAGAI SUMBER ENERGI ALTERNATIF." EnviroScienteae 17, no. 1 (August 16, 2021): 24. http://dx.doi.org/10.20527/es.v17i1.11350.

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Indonesia with a country that has a tropical climate and a very large intensity of solar radiation so that it can be developed into an alternative energy source by utilizing sea air. The purpose of this research is whether there is an effect of solar radiation on sea air on the power it produces as an alternative energy. Seawater as much as 300ml is put into a square glass container and paired with a series of Cu - Zn, Cu - Al, and Al - CuZn electrode plates with a cross-sectional area of 15cm2 of each electrode and connected to a red LED light to see how much power is generated by sea water after being exposed to solar radiation at different temperatures and times. Data obtained at the highest temperature of 33°C and the duration of exposure to solar radiation for 60 minutes in the 6th experiment with a variation of Cu - Zn electrodes with an electric power of 1,44 J/s, the lights are brightly lit, Cu - Al with electric power of 1,22 J/s of dim light, and Al - CuZn obtained electric power of 0,65 J/s. So it is concluded that the longer the sea water is exposed to solar radiation, the higher the temperature is due to the more heat stored in sea water. The conclusion was drawn that the higher the sea water temperature, the electric power produced, the higher the electric power generated and the lights can light up brightly at certain electrodes.

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Balasi, K. G., T. Domvoglou, I. Kiskiras, D. Lenis, N. Maragos, and G. Stavropoulos. "Deployment of an autonomous apparatus for measuring light scattering in deep sea." HNPS Proceedings 24 (April 1, 2019): 199. http://dx.doi.org/10.12681/hnps.1865.

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The KM3NeT research infrastructure will be a deep sea multidisciplinary observatory in the Mediterranean Sea housing a neutrino telescope. Accurate knowledge of the optical properties of the sea water is important for the best performance of the telescope. In this work we describe the deployment of the equipment that we had previously examined by Monte Carlo (MC) simulations1, in the context of the “scattering experiment” in order to evaluate the parameters describing the scattering characteristics of the sea water.

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TAKAHASHI, Kazunobu, Takanori YOSHINO, and Yoshihiko OHYAGI. "Photodegradation of tributyltin chloride in sea water by ultraviolet light." NIPPON KAGAKU KAISHI, no. 2 (1987): 181–85. http://dx.doi.org/10.1246/nikkashi.1987.181.

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Prelle, Lara R., and Ulf Karsten. "Photosynthesis, Respiration, and Growth of Five Benthic Diatom Strains as a Function of Intermixing Processes of Coastal Peatlands with the Baltic Sea." Microorganisms 10, no. 4 (March 30, 2022): 749. http://dx.doi.org/10.3390/microorganisms10040749.

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In light of climate change, renaturation of peatlands has become increasingly important, due to their function as carbon sinks. Renaturation processes in the Baltic Sea include removal of coastal protection measures thereby facilitating exchange processes between peatland and Baltic Sea water masses with inhabiting aquatic organisms, which suddenly face new environmental conditions. In this study, two Baltic Sea and three peatland benthic diatom strains were investigated for their ecophysiological response patterns as a function of numerous growth media, light, and temperature conditions. Results clearly showed growth stimulation for all five diatom strains when cultivated in peatland water-based media, with growth dependency on salinity for the Baltic Sea diatom isolates. Nutrient availability in the peatland water resulted in higher growth rates, and growth was further stimulated by the carbon-rich peatland water probably facilitating heterotrophic growth in Melosira nummuloides and two Planothidium sp. isolates. Photosynthesis parameters for all five diatom strains indicated low light requirements with light saturated photosynthesis at <70 µmol photons m−2 s−1 in combination with only minor photoinhibition as well as eurythermal traits with slightly higher temperature width for the peatland strains. Growth media composition did not affect photosynthetic rates.

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Castellani, Giulia, Gaëlle Veyssière, Michael Karcher, Julienne Stroeve, S. Neil Banas, A. Heather Bouman, S. Andrew Brierley, et al. "Shine a light: Under-ice light and its ecological implications in a changing Arctic Ocean." Ambio 51, no. 2 (November 25, 2021): 307–17. http://dx.doi.org/10.1007/s13280-021-01662-3.

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AbstractThe Arctic marine ecosystem is shaped by the seasonality of the solar cycle, spanning from 24-h light at the sea surface in summer to 24-h darkness in winter. The amount of light available for under-ice ecosystems is the result of different physical and biological processes that affect its path through atmosphere, snow, sea ice and water. In this article, we review the present state of knowledge of the abiotic (clouds, sea ice, snow, suspended matter) and biotic (sea ice algae and phytoplankton) controls on the underwater light field. We focus on how the available light affects the seasonal cycle of primary production (sympagic and pelagic) and discuss the sensitivity of ecosystems to changes in the light field based on model simulations. Lastly, we discuss predicted future changes in under-ice light as a consequence of climate change and their potential ecological implications, with the aim of providing a guide for future research.

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Chen, Yubin, Wenyu Zheng, Sebastián Murcia-López, Fei Lv, Joan Ramón Morante, Lionel Vayssieres, and Clemens Burda. "Light management in photoelectrochemical water splitting – from materials to device engineering." Journal of Materials Chemistry C 9, no. 11 (2021): 3726–48. http://dx.doi.org/10.1039/d0tc06071b.

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Tiwari, T. N. "Attenuation of Visible Light in the Sea-water; Some Empirical Relations." Journal of Optics 14, no. 1 (March 1985): 44–45. http://dx.doi.org/10.1007/bf03549121.

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Levin, I. M., M. A. Rodionov, and O. N. Frantsuzov. "Submersible device for measuring the light-attenuation index of sea water." Journal of Optical Technology 78, no. 5 (May 31, 2011): 328. http://dx.doi.org/10.1364/jot.78.000328.

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Luchinin, Alexander G. "Light pulse propagation along the path atmosphere–rough-surface–sea water." Applied Optics 49, no. 27 (September 17, 2010): 5059. http://dx.doi.org/10.1364/ao.49.005059.

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Epps, Helen H. "Degradation of Swimwear Fabrics: Effects of Light, Sea Water and Chlorine." Clothing and Textiles Research Journal 5, no. 2 (January 1987): 28–32. http://dx.doi.org/10.1177/0887302x8700500205.

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Shinde, S. S., C. H. Bhosale, and K. Y. Rajpure. "Photocatalytic activity of sea water using TiO2 catalyst under solar light." Journal of Photochemistry and Photobiology B: Biology 103, no. 2 (May 2011): 111–17. http://dx.doi.org/10.1016/j.jphotobiol.2011.02.002.

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Stolle, Christian, Mariana Ribas-Ribas, Thomas H. Badewien, Jonathan Barnes, Lucy J. Carpenter, Rosie Chance, Lars Riis Damgaard, et al. "The MILAN Campaign: Studying Diel Light Effects on the Air–Sea Interface." Bulletin of the American Meteorological Society 101, no. 2 (February 1, 2020): E146—E166. http://dx.doi.org/10.1175/bams-d-17-0329.1.

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Abstract The sea surface microlayer (SML) at the air–sea interface is <1 mm thick, but it is physically, chemically, and biologically distinct from the underlying water and the atmosphere above. Wind-driven turbulence and solar radiation are important drivers of SML physical and biogeochemical properties. Given that the SML is involved in all air–sea exchanges of mass and energy, its response to solar radiation, especially in relation to how it regulates the air–sea exchange of climate-relevant gases and aerosols, is surprisingly poorly characterized. MILAN (Sea Surface Microlayer at Night) was an international, multidisciplinary campaign designed to specifically address this issue. In spring 2017, we deployed diverse sampling platforms (research vessels, radio-controlled catamaran, free-drifting buoy) to study full diel cycles in the coastal North Sea SML and in underlying water, and installed a land-based aerosol sampler. We also carried out concurrent ex situ experiments using several microsensors, a laboratory gas exchange tank, a solar simulator, and a sea spray simulation chamber. In this paper we outline the diversity of approaches employed and some initial results obtained during MILAN. Our observations of diel SML variability show, for example, an influence of (i) changing solar radiation on the quantity and quality of organic material and (ii) diel changes in wind intensity primarily forcing air–sea CO2 exchange. Thus, MILAN underlines the value and the need of multidiciplinary campaigns for integrating SML complexity into the context of air–sea interaction.

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Tsukihara, Tsutomu. "WEATHERING EXPERIMENT ON SPILLED CRUDE OILS USING A CIRCULATING WATER CHANNEL." International Oil Spill Conference Proceedings 1995, no. 1 (February 1, 1995): 435–22. http://dx.doi.org/10.7901/2169-3358-1995-1-435.

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ABSTRACT Crude oil spilled in the sea is mixed with the sea water by the wind and waves resulting in increases in its water content and viscosity as time passes. We have constructed a small, transfer type circulating water channel of an elliptical cuit-track form. Using an attached circulating unit, together with a war tunnel, artificial waves are generated to enable simulation corresponding to the natural circumstances in the sea. The experiment disclosed the following results.Drastic changes in the properties (water content and viscosity) of the oil depend on the power of waves.Contrasting processes are observed between heavy and light crude oils during weathering.Heavy crude oils form a massive water-in-oil emulsion (mousse) with increases in both water content and viscosity.Light crude oils behave differently at summer sea temperatures,

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Baszanowska, Emilia, Zbigniew Otremba, and Jacek Piskozub. "Modelling the Visibility of Baltic-Type Crude Oil Emulsion Dispersed in the Southern Baltic Sea." Remote Sensing 13, no. 10 (May 14, 2021): 1917. http://dx.doi.org/10.3390/rs13101917.

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This paper analyses the radiance reflectance modelling of a sea area and the case of a water column polluted with an oil emulsion in relation to various depths of the occurrence of an oil-in-water emulsion in all azimuth and zenith angles. For the radiance reflectance modelling, the simulation of large numbers of solar photons in water was performed using a Monte Carlo simulation. For the simulations, the optical properties of seawater for the open sea typical of the southern Baltic Sea were used and Petrobaltic-type crude oil (extracted in the Baltic Sea) was added. Oil pollution in the sea was considered for oil droplet concentrations of 10 ppm, which were optically represented by spectral waveforms of absorption and scattering coefficients, as well as by angular light scattering distribution determined using the Mie theory. The results of the radiance reflectance modelling in the whole spectrum of both angles, azimuth and zenith, allowed us to select 555 nm as the optimal wavelength for oil emulsion detection. Moreover, the parameter contrast was defined and determined using radiance reflectance results for eight light wavelengths in the range of 412-676 nm. The contrast is discussed in relation to the various thicknesses of polluted water layers. Changes in contrast for a thickness layer 5 m under the sea surface were noted, whereas for thicker layers the contrast remained unchanged.

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Neumann, Thomas, Herbert Siegel, Matthias Moros, Monika Gerth, Madline Kniebusch, and Daniel Heydebreck. "Ventilation of the northern Baltic Sea." Ocean Science 16, no. 4 (July 3, 2020): 767–80. http://dx.doi.org/10.5194/os-16-767-2020.

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Abstract. The Baltic Sea is a semi-enclosed, brackish water sea in northern Europe. The deep basins of the central Baltic Sea regularly show hypoxic conditions. In contrast, the northern parts of the Baltic Sea, the Bothnian Sea and Bothnian Bay, are well oxygenated. Lateral inflows or a ventilation due to convection are possible mechanisms for high oxygen concentrations in the deep water of the northern Baltic Sea. In March 2017, conductivity–temperature–depth (CTD) profiles and bottle samples, ice core samples, and brine were collected in the Bothnian Bay. In addition to hydrographic standard parameters, light absorption has been measured in all samples. A complementary numerical model simulation provides quantitative estimates of the spread of newly formed bottom water. The model uses passive and age tracers to identify and trace different water masses. Observations indicate a recent ventilation of the deep bottom water at one of the observed stations. The analysis of observations and model simulations shows that the Bothnian Bay is ventilated by dense water formed due to mixing of Bothnian Sea and Bothnian Bay surface water initializing lateral inflows. The observations show the beginning of the inflow and the model simulation demonstrates the further northward spreading of bottom water. These events occur during wintertime when the water temperature is low. Brine rejected during ice formation barely contributes to dense bottom water.

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ZENG Shan-shan, 曾珊珊, 金尚忠 JIN Shang-zhong, 王毓蓉 WANG Yu-rong, 石昌寿 SHI Chang-shou, and 鲁玉红 LU Yu-hong. "Penetration Properties of LED Light Sources in Water Fog and Sea Fog." ACTA PHOTONICA SINICA 42, no. 10 (2013): 1140–46. http://dx.doi.org/10.3788/gzxb20134210.1140.

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Gorodnichev, Evgeniy E., Kirill A. Kondratiev, Alexandr I. Kuzovlev, and Dmitrii B. Rogozkin. "Propagation and Depolarization of a Short Pulse of Light in Sea Water." Journal of Marine Science and Engineering 8, no. 5 (May 23, 2020): 371. http://dx.doi.org/10.3390/jmse8050371.

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We present the results of a theoretical study of underwater pulse propagation. The vector radiative transfer equation (VRTE) underlies our calculations of the main characteristics of the scattered light field in the pulse. Under the assumption of highly forward scattering in seawater, three separate equations for the basic modes are derived from the exact VRTE. These three equations are further solved both within the small-angle approximation and numerically. The equation for the intensity is analyzed for a power-law parametrization of the wings of the sea water phase function. The distribution of early arrival photons in the pulse, including the peak intensity, is calculated. Simple relations are also presented for the variance of the angular distribution of radiation, the effective duration of the signal and other parameters of the pulse. For linearly and circularly polarized pulses, the temporal profile of the degree of polarization is calculated for actual data on the scattering matrix elements. The degree of polarization is shown to be described by the self-similar dependence on some combination of the transport scattering coefficient, the temporal delay and the source-receiver distance. Our results are in agreement with experimental and Monte-Carlo simulation data. The conclusions of the paper offer a theoretical groundwork for application to underwater imaging, communication and remote sensing.

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Luchinin, Alexander G., and Mikhail Yu Kirillin. "Temporal and frequency characteristics of a narrow light beam in sea water." Applied Optics 55, no. 27 (September 20, 2016): 7756. http://dx.doi.org/10.1364/ao.55.007756.

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Claes, Julien M., and Jérôme Mallefet. "The lantern shark's light switch: turning shallow water crypsis into midwater camouflage." Biology Letters 6, no. 5 (April 21, 2010): 685–87. http://dx.doi.org/10.1098/rsbl.2010.0167.

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Bioluminescence is a common feature in the permanent darkness of the deep-sea. In fishes, light is emitted by organs containing either photogenic cells (intrinsic photophores), which are under direct nervous control, or symbiotic luminous bacteria (symbiotic photophores), whose light is controlled by secondary means such as mechanical occlusion or physiological suppression. The intrinsic photophores of the lantern shark Etmopterus spinax were recently shown as an exception to this rule since they appear to be under hormonal control. Here, we show that hormones operate what amounts to a unique light switch, by acting on a chromatophore iris, which regulates light emission by pigment translocation. This result strongly suggests that this shark's luminescence control originates from the mechanism for physiological colour change found in shallow water sharks that also involves hormonally controlled chromatophores: the lantern shark would have turned the initial shallow water crypsis mechanism into a midwater luminous camouflage, more efficient in the deep-sea environment.

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Yang, Xiguang, Jie Chen, and Ying Yu. "Analysis of the Bidirectional Characteristic of Radiation of Flat and Rough Water–Air Interfaces Based on the Theory of Radiative Transfer." Sustainability 15, no. 1 (December 22, 2022): 140. http://dx.doi.org/10.3390/su15010140.

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The Lambertian property of objects is one of the basic hypotheses in remote sensing research. However, the spectral radiance of natural objects is always anisotropic. On the sea surface, a large amount of sea foam is generated at the water–air interface, induced by wind speed and breaking gravity waves. Additionally, the scattering characteristic at the water–air interface significantly influences the accuracy of ocean color remote sensing and its output. The bidirectionality of the water light field is one of the sources of errors in ocean color inversion. Therefore, the knowledge of the bidirectional reflectance distribution of water surfaces is of great significance in quantitative remote sensing or for the evaluation of measurement errors in surface optical parameters. To clarify the bidirectional reflectance distribution, we used the coupled ocean–atmosphere radiative transfer (COART) model to simulate the bidirectional radiance of water bodies and explored the anisotropy of radiance at the water–air interface. The results indicate that the downward and upward irradiance just below the water surface and the water-leaving radiance changed with the sun-viewing geometry. The downward and upward radiance just below the water surface decreased as the zenith angle of the incident light increased. This effect can be mitigated using a function of the viewing angle. Additionally, the viewing azimuth angle and rough sea surface had no significant effect on the downward and upward radiance. The water-leaving radiance had an obvious bidirectional reflectance characteristic. Additionally, a backward hotspot was found in the simulated results. Then, the transmission coefficient was calculated, and the bidirectional distribution characteristic was found for flat and rough sea surfaces. This study can be used as a reference to correct bidirectional errors and to guide the spectral measurements of water and its error control for rough sea surfaces.

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Losseva, T. V., and I. V. Nemchinov. "Earthquake lights and rupture processes." Natural Hazards and Earth System Sciences 5, no. 5 (September 8, 2005): 649–56. http://dx.doi.org/10.5194/nhess-5-649-2005.

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Abstract. A physical model of earthquake lights is proposed. It is suggested that the magnetic diffusion from the electric and magnetic fields source region is a dominant process, explaining rather high localization of the light flashes. A 3D numerical code allowing to take into account the arbitrary distribution of currents caused by ground motion, conductivity in the ground and at its surface, including the existence of sea water above the epicenter or (and) near the ruptured segments of the fault have been developed. Simulations for the 1995 Kobe earthquake were conducted taking into account the existence of sea water with realistic geometry of shores. The results do not contradict the eyewitness reports and scarce measurements of the electric and magnetic fields at large distances from the epicenter.

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Watanabe, N., S. Sakai, and H. Takatsuki. "Examination for Degradation Paths of Butyltin Compounds in Natural Waters." Water Science and Technology 25, no. 11 (June 1, 1992): 117–24. http://dx.doi.org/10.2166/wst.1992.0282.

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Examination of individual degradation paths (biodegradation and photolysis) of butyltin compounds (especially tributyltin: TBT) in natural waters was performed. Biodegradation of TBT and dibutyltin (DBT) in an unfiltered sea water in summer is rather fast; their half life is about a week. But pretreatment with glass fiber filter makes the half life of TBT much longer (about 80 days). Photolysis of TBT in sea water by sun light is rapid (half life is about 0.5 days), and faster than in distilled water or in fresh water. Degradation rates of each process for TBT are calculated in various conditions of sea water, and contribution rates are compared. Biodegradation will be the main degradation process in an “SS-rich” area such as a marina, but photolysis will exceed that in a “clean” area. Over all half lives of TBT in sea water vary from 6 days to 127 days considering seasons and presence of SS.

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Son, Hyun-Joong, Hyeung-Sik Choi, Ngoc-Huy Tran, Ji-Hoon Ha, Dae-Hyeung Ji, and Joon-Young Kim. "Study on underwater wireless communication system using LED." Modern Physics Letters B 29, no. 06n07 (March 20, 2015): 1540023. http://dx.doi.org/10.1142/s0217984915400230.

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In this paper, a new variable-focus LED light device is developed for underwater communication. Usually used as an underwater lighting fixture, the LED light device in this study is utilized as an underwater communication device (UCD) by controlling the distance between light source and lens when communication is needed. A transmission and a receiving part of LED light for communication using photoelectric sensor and Fresnel lens are also developed. The communication system was tested in fresh water and sea water to verify its communication performance; results of which are presented in this study.

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Freda, Włodzimierz, Kamila Haule, and Sławomir Sagan. "On the role of the seawater absorption-to-attenuation ratio in the radiance polarization above the southern Baltic surface." Ocean Science 15, no. 3 (June 17, 2019): 745–59. http://dx.doi.org/10.5194/os-15-745-2019.

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Abstract. Information about polarization of light leaving the ocean surface has the potential to improve the quality of bio-optical parameter retrieval from ocean color remote sensing (OCRS). This improvement can be applied in numerous ways, such as limiting of Sun glints and obtaining information about atmospheric aerosol properties for atmospheric correction as well as increasing the accuracy of the algorithms based on the water-leaving signal. Polarization signals at the top of the atmosphere (ToA) that include the water-leaving signal are strongly influenced by atmospheric molecular scattering and by direct Sun and sky reflections from the sea surface. For these reasons, it is necessary to better understand the factors that change the polarization of light in the atmosphere–ocean system, especially in coastal zones affected by dynamic changes. In this paper, the influence of seasonal variability of light absorption and scattering coefficients (inherent optical properties; IOPs) of seawater, wind speed and solar zenith angle (SZA) on the polarization of upwelling radiance over the sea surface in the visible light bands is discussed. The results come from a polarized radiative transfer model based on the Monte Carlo code and applied to the atmosphere–ocean system using averaged IOPs as input data. The results, presented in the form of polar plots of the total upwelling radiance degree of polarization (DoP), indicate that regardless of the wavelength of light and type of water, the highest value of the above-water DoP is strongly correlated with the absorption-to-attenuation ratio. The correlation is a power function that depends on both the SZA and the wind speed. The correlation versatility for different wavelengths of light is very unusual in optics of the sea and is therefore worth emphasizing.

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Wei, J. D., G. Q. Zhou, X. Zhou, J. L. Chen, Y. Z. Tan, and H. C. Hu. "DESIGN OF THREE-CHANNEL OPTICAL RECEIVING SYSTEM FOR DUAL-FREQUENCY LASER RADAR." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W10 (February 8, 2020): 815–19. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w10-815-2020.

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Abstract. There are many intertidal zones and island reefs in the coastal area, the traditional shipborne acoustic measurement method is extremely inefficient, so the coastal area three-dimensional integrated measurement has always been a difficult point in the field of remote sensing. Because the sea blue-green light window has good transparency and the laser point cloud data can quickly and accurately distinguish the characteristics of shallow sea water topography. At present, the most effective detection method for coastal areas in the world is the airborne dual-frequency laser radar detection technology, which has high measurement rate and wide coverage. The laser outputs both 1064nm and 532nm dual-wavelength laser, 1064nm laser forms sea surface echo, and 532nm laser penetrates sea water to form shallow sea and deep sea echo. However, during the propagation of seawater, the number of photon scattering increases with the increase of water depth, which will cause the attenuation of the echo signal. As a result, the detection of weak light in the large dynamic range is not high, which has been a difficult point for near-shore airborne sounding. To solve this problem, we designed a split-field, three-channel optical receiving system. The ZEMAX simulation results show that the dual-channel laser radar three-channel receiving optical system effectively reduces the optical crosstalk between the optical components and the channels, and achieves energy harvesting in different water depth channels. The structure dynamically compresses the photoelectric signal and improves the signal to noise ratio.

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Bélanger, S., S. A. Cizmeli, J. Ehn, A. Matsuoka, D. Doxaran, S. Hooker, and M. Babin. "Light absorption and partitioning in Arctic Ocean surface waters: impact of multi year ice melting." Biogeosciences Discussions 10, no. 3 (March 21, 2013): 5619–70. http://dx.doi.org/10.5194/bgd-10-5619-2013.

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Abstract. Ice melting in the Arctic Ocean exposes the surface water to more radiative energy with poorly understood effects on photo-biogeochemical processes and heat deposition in the upper ocean. In August 2009, we documented the vertical variability of light absorbing components at 37 stations located in the southeastern Beaufort Sea including both Mackenzie river-influenced waters and polar mixed layer waters. We found that melting multi-year ice released significant amount of non-algal particulates (NAP) near the sea surface relative to sub-surface waters. NAP absorption coefficients at 440 nm (aNAP(440)) immediately below the sea surface (0-) were on average 3-fold (up to 10-fold) higher compared to sub-surface values measured at 2–3 m depth. The impact of this unusual feature on the light transmission and remote sensing reflectance (Rrs) was further examined using a radiative transfer model. A 10-fold particle enrichment homogeneously distributed in the first meter of the water column slightly reduced photosynthetically available and usable radiation (PAR and PUR) by ~6% and ~8%, respectively, relative to a fully homogenous water column with low particles concentration. In terms of Rrs, the particle enrichment significantly flattered the spectrum by reducing the Rrs by up to 20% in the blue-green spectral region (400–550 nm). These results highlight the impact of melt water on the concentration of particles at sea surface, and the need for considering nonuniform vertical distribution of particles in such systems when interpreting remotely sensed ocean color. Spectral slope of aNAP spectra calculated in the UV domain decreased with depth suggesting that this parameter is sensitive to detritus composition and/or diagenesis state (e.g., POM photobleaching).

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Massicotte, Philippe, Guislain Bécu, Simon Lambert-Girard, Edouard Leymarie, and Marcel Babin. "Estimating Underwater Light Regime under Spatially Heterogeneous Sea Ice in the Arctic." Applied Sciences 8, no. 12 (December 19, 2018): 2693. http://dx.doi.org/10.3390/app8122693.

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The vertical diffuse attenuation coefficient for downward plane irradiance ( K d ) is an apparent optical property commonly used in primary production models to propagate incident solar radiation in the water column. In open water, estimating K d is relatively straightforward when a vertical profile of measurements of downward irradiance, E d , is available. In the Arctic, the ice pack is characterized by a complex mosaic composed of sea ice with snow, ridges, melt ponds, and leads. Due to the resulting spatially heterogeneous light field in the top meters of the water column, it is difficult to measure at single-point locations meaningful K d values that allow predicting average irradiance at any depth. The main objective of this work is to propose a new method to estimate average irradiance over large spatially heterogeneous area as it would be seen by drifting phytoplankton. Using both in situ data and 3D Monte Carlo numerical simulations of radiative transfer, we show that (1) the large-area average vertical profile of downward irradiance, E d ¯ ( z ) , under heterogeneous sea ice cover can be represented by a single-term exponential function and (2) the vertical attenuation coefficient for upward radiance ( K L u ), which is up to two times less influenced by a heterogeneous incident light field than K d in the vicinity of a melt pond, can be used as a proxy to estimate E d ¯ ( z ) in the water column.

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Novales Flamarique, Iñigo, Christina Gulbransen, Moira Galbraith, and Dario Stucchi. "Monitoring and potential control of sea lice using an LED-based light trap." Canadian Journal of Fisheries and Aquatic Sciences 66, no. 8 (August 2009): 1371–82. http://dx.doi.org/10.1139/f09-094.

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Sea lice are ectoparasitic copepods that threaten salmon farming aquaculture and the viability of wild salmon populations. To control infestations on farmed salmon, several chemotherapeutants have been developed, but these are invasive (often causing fish stress and loss in production), costly, may induce parasite resistance over time, and their impact on the environment is a major social concern. Here, we show that a light-emitting diode (LED)-based light trap can be used to monitor sea lice presence on fish and in the water. The performance of the light trap was tested in experimental tanks and in the ocean. Plankton net tows were also performed to compare catches with those from light traps. The light trap caught ~70% of salmon lice larval stages loaded onto a tank and ~24% of the adults. It also acted as a delousing agent by removing ~8% of adult salmon lice infective on Chinook salmon ( Oncorhynchus tshawytscha ) smolts in tank experiments. In the ocean, the light trap caught 21 sea lice (10 Lepeophtheirus salmonis and 11 Caligus clemensi ), comprising free-swimming and attached stages, while plankton net tows failed to capture any. We conclude that light traps constitute an effective, noninvasive, environmentally friendly method to monitor sea lice.

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Hoffmann, Ralf, Ulrike Braeckman, Christiane Hasemann, and Frank Wenzhöfer. "Deep-sea benthic communities and oxygen fluxes in the Arctic Fram Strait controlled by sea-ice cover and water depth." Biogeosciences 15, no. 16 (August 16, 2018): 4849–69. http://dx.doi.org/10.5194/bg-15-4849-2018.

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Abstract. Arctic Ocean surface sea-ice conditions are linked with the deep sea benthic oxygen fluxes via a cascade of interdependencies across ecosystem components such as primary production, food supply, activity of the benthic community, and their functions. Additionally, each ecosystem component is influenced by abiotic factors such as light availability, temperature, water depth, and grain size structure. In this study, we investigated the coupling between surface sea-ice conditions and deep-sea benthic remineralization processes through a cascade of interdependencies in the Fram Strait. We measured sea-ice concentrations, a variety of different sediment characteristics, benthic community parameters, and oxygen fluxes at 12 stations of the LTER HAUSGARTEN observatory, Fram Strait, at water depths of 275–2500 m. Our investigations reveal that the Fram Strait is bisected into two long-lasting and stable regions: (i) a permanently and highly sea-ice-covered area and (ii) a seasonally and low sea-ice-covered area. Within the Fram Strait ecosystem, sea-ice concentration and water depth are two independent abiotic factors, controlling the deep-sea benthos. Sea-ice concentration correlated with the available food and water depth with the oxygen flux. In addition, both abiotic factors sea-ice concentration and water depth correlate with the macrofauna biomass. However, at water depths > 1500 m the influence of the surface sea-ice cover is minimal with water depth becoming more dominant. Benthic remineralization across the Fram Strait on average is ∼ 1 mmol C m−2 d−1. Our data indicate that the portion of newly produced carbon that is remineralized by the benthos is 5 % in the seasonally low sea-ice-covered eastern part of Fram Strait but can be 14 % in the permanently high sea-ice-covered western part of Fram Strait. Here, by comparing a permanently sea-ice-covered area with a seasonally sea-ice-covered area, we discuss a potential scenario for the deep-sea benthic ecosystem in the future Arctic Ocean, in which an increased surface primary production may lead to increasing benthic remineralization at water depths < 1500 m.

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Koesdijati, Titik. "THE USE OF SUNLIGHT FOR SUSPENSION OF SALT WATER WITH CONVERGEN CONVERSION LENS." Tibuana 1, no. 1 (August 1, 2018): 56–60. http://dx.doi.org/10.36456/tibuana.1.1.1592.56-60.

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Salt in the main need for humans, In the process of shrinkage of salt products become the expected result is always increased because in the islands of Madura who have high salt income can be utilized. Light focus can be used through convex convex lens to increase sea water shrinkage so as to accelerate evaporation as well Get shrinkage of salt water salt raw material quickly. From observations made in May - June 2017 can be obtained data focusing light through convex convex lens is by focusing the sun on convex lens that is directed at sea water, so it can shrink the water faster. Acquisition of water depreciation using the tool obtained 95,000 cc / 95 liters, while 47.000 cc / 47 liters obtained from without tools. From this study it can be concluded that the value obtained yields a positive value, where the use of the tool from the volume of each volume filled 100 liters with a ratio of 1: 1 from the analysis obtained from using a tool faster 56% using tools with upper 14322.90 Of the 99% confidence interval received. So from the shrinkage using a faster tool, the depreciation of sea salt raw materials with convergent convex lenses can be applied directly as a technological reasoning.

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31

Velásquez, A., E. Sira, S. Silva, and H. Cabrera. "Experimental study of the light absorption in sea water by thermal lens spectroscopy." Journal of Physics: Conference Series 672 (January 20, 2016): 012021. http://dx.doi.org/10.1088/1742-6596/672/1/012021.

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32

Kozarac, Z., D. Risović, S. Frka, and D. Möbius. "Reflection of light from the air/water interface covered with sea-surface microlayers." Marine Chemistry 96, no. 1-2 (August 2005): 99–113. http://dx.doi.org/10.1016/j.marchem.2004.12.003.

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33

Larsen, Roger B., Bent Herrmann, Manu Sistiaga, Jure Brčić, Jesse Brinkhof, and Ivan Tatone. "Could green artificial light reduce bycatch during Barents Sea Deep-water shrimp trawling?" Fisheries Research 204 (August 2018): 441–47. http://dx.doi.org/10.1016/j.fishres.2018.03.023.

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34

Lerner, Amit, Shai Sabbah, Carynelisa Erlick, and Nadav Shashar. "Navigation by light polarization in clear and turbid waters." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1565 (March 12, 2011): 671–79. http://dx.doi.org/10.1098/rstb.2010.0189.

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Certain terrestrial animals use sky polarization for navigation. Certain aquatic species have also been shown to orient according to a polarization stimulus, but the correlation between underwater polarization and Sun position and hence the ability to use underwater polarization as a compass for navigation is still under debate. To examine this issue, we use theoretical equations for per cent polarization and electric vector (e-vector) orientation that account for the position of the Sun, refraction at the air–water interface and Rayleigh single scattering. The polarization patterns predicted by these theoretical equations are compared with measurements conducted in clear and semi-turbid coastal sea waters at 2 m and 5 m depth over sea floors of 6 m and 28 m depth. We find that the per cent polarization is correlated with the Sun's elevation only in clear waters. We furthermore find that the maximum value of the e-vector orientation angle equals the angle of refraction only in clear waters, in the horizontal viewing direction, over the deeper sea floor. We conclude that navigation by use of underwater polarization is possible under restricted conditions, i.e. in clear waters, primarily near the horizontal viewing direction, and in locations where the sea floor has limited effects on the light's polarization.

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35

Evison, L. M. "Comparative Studies on the Survival of Indicator Organisms and Pathogens in Fresh and Sea Water." Water Science and Technology 20, no. 11-12 (November 1, 1988): 309–15. http://dx.doi.org/10.2166/wst.1988.0300.

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Results are reported from a comprehensive series of experiments in which the survival characteristics of a range of indicator bacteria, pathogenic bacteria and bacteriophages was compared in fresh and seawater in the light, and at a range of temperatures, nutrient concentrations and salinities in the dark. Survival of the following organisms was studied: E.coli, faecal streptococci, maroon faecal streptococci, Salmonellatyphimurium 12, 12a and 110, S. anatum, Shigellasonnei, Sh. flexneri, Yersinia enterocolitica, Campylobacter fetus, Coliphages MS 2 and f 2. The data shows that in the light the survival of E.coli was very poor compared to that of Salmonellae. In the light, survival was best in fresh water, but in the dark survival in seawater was usually better. A linear relationship was demonstrated for T,90 and light intensity, and log T90 and temperature, but non-linear responses occurred for a range of salinities and nutrient concentrations.

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36

Gosselin, M., L. Legendre, S. Demers, and R. G. Ingram. "Responses of Sea-Ice Microalgae to Climatic and Fortnightly Tidal Energy Inputs (Manitounuk Sound, Hudson Bay)." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 5 (May 1, 1985): 999–1006. http://dx.doi.org/10.1139/f85-125.

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Variations of sea-ice microalgae at the ice–water interface (Manitounuk Sound, Hudson Bay, Canada) were studied in relation to various energy inputs (light, tidal mixing, and heat) in April and May 1982. Seasonal photosynthetic activity does not start before the light intensity reaches 7.6 μEinst∙m−2∙s−1. Above this value, the seasonal increase in cell numbers and chlorophyll and in the photoadaptation index (Ik) is related to the increase in underice light intensity. The sea-ice community changes from shade to light adaptation to optimize the use of ambient light energy. Photosynthetic efficiency (αB) is mainly controlled by the fortnightly tidal vertical mixing, which governs the amount of phosphate (or of another nutrient factor) in the upper brackish layer. The ice microflora, which grows at a stable interface, takes advantage of nutrient replenishment during mixed water column conditions. We conclude that production of microalgae depends upon three forms of energy: (1) the flux of solar light, (2) the inputs of auxiliary mechanical energy (here, the fortnightly tides), and (3) the energy exchanges (here, the heat flux) responsible for the maintenance or destruction of energetic interfaces (ergoclines).

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37

Mewoh, Erixio, Patricia Silangen, Alfrie Rampengan, and Christophil Medellu. "PROFIL VERTIKAL DAN LUAS BIDANG DINAMIKA HARIAN GRADIEN SUHU UDARA DI ATAS PERMUKAAN AIR LAUT DAN DI DALAM AIR LAUT." Jurnal FisTa : Fisika dan Terapannya 2, no. 2 (October 31, 2021): 82–87. http://dx.doi.org/10.53682/fista.v2i2.133.

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The temperature in sea water varies at each depth. The temperature of sea water at the surface is higher and the temperature at a deeper point is decreasing slowly. This study aims to determine the model of the temporal, spatial function, and dynamic models of daily temperature gradients above sea level and in sea water. This type of research is included in the type of exploratory research that is quantitative in nature. The research is in Tulaun hamlet, Lalumpe Village, Kombi District, Minahasa Regency, North Sulawesi Province, Indonesia. The research was conducted for 24 hours at 9 points, ranging from 0 cm, 10 cm, 30 cm, 60 cm, 100 cm, 150 cm, 220 cm, 300cm, to 400cm. The research variables were temperature and light intensity. Data processing in this study is to enter existing data into the Matlab application. The results of the study of changes in the functional model above sea level and in seawater are influenced by the heat absorption process of air temperature.

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Bélanger, S., S. A. Cizmeli, J. Ehn, A. Matsuoka, D. Doxaran, S. Hooker, and M. Babin. "Light absorption and partitioning in Arctic Ocean surface waters: impact of multiyear ice melting." Biogeosciences 10, no. 10 (October 11, 2013): 6433–52. http://dx.doi.org/10.5194/bg-10-6433-2013.

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Abstract. Ice melting in the Arctic Ocean exposes the surface water to more radiative energy with poorly understood effects on photo-biogeochemical processes and heat deposition in the upper ocean. In August 2009, we documented the vertical variability of light absorbing components at 37 stations located in the southeastern Beaufort Sea including both Mackenzie River-influenced waters and polar mixed layer waters. We found that melting multiyear ice released significant amount of non-algal particulates (NAP) near the sea surface relative to subsurface waters. NAP absorption coefficients at 440 nm (aNAP(440)) immediately below the sea surface were on average 3-fold (up to 10-fold) higher compared to subsurface values measured at 2–3 m depth. The impact of this unusual feature on the light transmission and remote sensing reflectance (Rrs) was further examined using a radiative transfer model. A 10-fold particle enrichment homogeneously distributed in the first meter of the water column slightly reduced photosynthetically available and usable radiation (PAR and PUR) by ∼6 and ∼8%, respectively, relative to a fully homogenous water column with low particle concentration. In terms of Rrs, the particle enrichment significantly flattered the spectrum by reducing the Rrs by up to 20% in the blue-green spectral region (400–550 nm). These results highlight the impact of meltwater on the concentration of particles at sea surface, and the need for considering non-uniform vertical distribution of particles in such systems when interpreting remotely sensed ocean color. Spectral slope of aNAP spectra calculated in the UV (ultraviolet) domain decreased with depth suggesting that this parameter is sensitive to detritus composition and/or diagenesis state (e.g., POM (particulate organic matter) photobleaching).

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39

Yanel, Karnova. "PROTOTYPE OF ARDUINO-BASED WATER LEVEL DETECTOR WITH ULTRASONIC SENSOR." Jurnal Ilmiah Teknik Mesin, Elektro dan Komputer 3, no. 1 (March 18, 2023): 125–32. http://dx.doi.org/10.51903/juritek.v3i1.1329.

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Most of the water can be found in the sea (salt water) and in the ice caps (at the poles and on the tops of mountains). Apart from that, water can also be found in clouds, rain, rivers, surface fresh water, lakes, water vapor, and sea ice. The water in these objects moves according to a water cycle, namely: through evaporation, rain, and the flow of water over the ground surface (runoff, including springs, rivers, estuaries) towards the sea. Floods are natural disaster events that occur when an excessive flow of water submerges land. Floods can occur within minutes or over a long period of time, and can last days, weeks, or longer. Floods are the most common and widespread of all weather-related natural disasters. The tool can function properly. The height can be set to be displayed with an LED light display. Can be applied to the floodgates to activate the motor driving the floodgates so that the water level through the floodgates can be adjusted in such a way.

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40

Wang, Jian Hua, Gang Li, Ya Zhou Xiong, and Kang Ke Liu. "Method of Detecting Sea State from Image Taken by Autonomous Surface Vehicle." Applied Mechanics and Materials 316-317 (April 2013): 475–78. http://dx.doi.org/10.4028/www.scientific.net/amm.316-317.475.

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Autonomous surface vehicle provides a safe approach to monitor environment on water surface in dangerous condition. This paper presents a method of sea state detection from images taken by a camera fixed on an autonomous surface vehicle. Based on texture feature of images from water surface scene, gray level co-occurrence matrix is computed, and its features including energy, contrast, correlation and entropy are extracted. Experiments show that the contrast can differentiate the sea state levels better than the others. To improve discrimination at low sea state levels, a transform is proposed. Performance of the method at different light shining conditions is discussed, and the results validate the method.

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41

Efimova, Tatiana, Tatiana Churilova, Elena Skorokhod, Vyacheslav Suslin, Anatoly S. Buchelnikov, Dmitry Glukhovets, Aleksandr Khrapko, and Natalia Moiseeva. "Light Absorption by Optically Active Components in the Arctic Region (August 2020) and the Possibility of Application to Satellite Products for Water Quality Assessment." Remote Sensing 15, no. 17 (September 4, 2023): 4346. http://dx.doi.org/10.3390/rs15174346.

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In August 2020, during the 80th cruise of the R/V “Akademik Mstislav Keldysh”, the chlorophyll a concentration (Chl-a) and spectral coefficients of light absorption by phytoplankton pigments, non-algal particles (NAP) and colored dissolved organic matter (CDOM) were measured in the Norwegian Sea, the Barents Sea and the adjacent area of the Arctic Ocean. It was shown that the spatial distribution of the three light-absorbing components in the explored Arctic region was non-homogenous. It was revealed that CDOM contributed largely to the total non-water light absorption (atot(λ) = aph(λ) + aNAP(λ) + aCDOM(λ)) in the blue spectral range in the Arctic Ocean and the Barents Sea. The fraction of NAP in the total non-water absorption was low (less than 20%). The depth of the euphotic zone depended on atot(λ) in the surface water layer, which was described by a power equation. The Arctic Ocean, the Norwegian Sea and the Barents Sea did not differ in the Chl-a-specific light absorption coefficients of phytoplankton. In the blue maximum of phytoplankton absorption spectra, Chl-a-specific light absorption coefficients of phytoplankton in the upper mixed layer (UML) were higher than those below the UML. Relationships between phytoplankton absorption coefficients and Chl-a were derived by least squares fitting to power functions for the whole visible domain with a 1 nm interval. The OCI, OC3 and GIOP algorithms were validated using a database of co-located results (day-to-day) of in situ measurements (n = 63) and the ocean color scanner data: the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra (EOS AM) and Aqua (EOS PM) satellites, the Visible and Infrared Imager/Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (S-NPP) and JPSS-1 satellites (also known as NOAA-20), and the Ocean and the Land Color Imager (OLCI) onboard the Sentinel-3A and Sentinel-3B satellites. The comparison showed that despite the technological progress in optical scanners and the algorithms refinement, the considered standard products (chlor_a, chl_ocx, aph_443, adg_443) carried little information about inherent optical properties in Arctic waters. Based on the statistic metrics (Bias, MdAD, MAE and RMSE), it was concluded that refinement of the algorithm for retrieval of water bio-optical properties based on remote sensing data was required for the Arctic region.

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42

Berschauer, David, Edward Petuch, and Roger Clark. "A New Species of Forreria (Gastropoda: Muricidae: Ocenebrinae) from the Sea of Cortez, Mexico." Festivus 50, no. 3 (August 1, 2018): 139–46. http://dx.doi.org/10.54173/f503139.

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A new muricid is described from deep water in the Wagner Basin, in the northern Sea of Cortez, Mexico, 65 kilometers south of Puerto Peňasco, Sonora, Mexico. The only living relative of this new species is Forreria belcheri (Hinds, 1843), which ranges from Santa Barbara, California, to Laguna Scammons, Baja California, Mexico. This new endemic species has been brought to light by shrimp trawling activities, and is thought to be a relict deep water population left behind in the northern Sea of Cortez during the Pleistocene.

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43

Williams, Siobhan, Walter Adey, Jochen Halfar, Andreas Kronz, Patrick Gagnon, David Bélanger, and Merinda Nash. "Effects of light and temperature on Mg uptake, growth, and calcification in the proxy climate archive <i>Clathromorphum</i> <i>compactum</i>." Biogeosciences 15, no. 19 (October 1, 2018): 5745–59. http://dx.doi.org/10.5194/bg-15-5745-2018.

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Abstract. The shallow-marine benthic coralline alga Clathromorphum compactum is an important annual- to sub-annual-resolution archive of Arctic and subarctic environmental conditions, allowing reconstructions going back > 600 years. Both Mg content, in the high-Mg calcitic cell walls, and annual algal growth increments have been used as a proxy for past temperatures and sea ice conditions. The process of calcification in coralline algae has been debated widely, with no definitive conclusion about the role of light and photosynthesis in growth and calcification. Light received by algal specimens can vary with latitude, water depth, sea ice conditions, water turbidity, and shading. Furthermore, field calibration studies of Clathromorphum sp. have yielded geographically disparate correlations between MgCO3 and sea surface temperature. The influence of other environmental controls, such as light, on Mg uptake and calcification has received little attention. We present results from an 11-month mesocosm experiment in which 123 wild-collected C. compactum specimens were grown in conditions simulating their natural habitat. Specimens grown for periods of 1 and 2 months in complete darkness show that the typical complex of anatomy and cell wall calcification develops in new tissue without the presence of light, demonstrating that calcification is metabolically driven and not a side effect of photosynthesis. Also, we show that both light and temperature significantly affect MgCO3 in C. compactum cell walls. For specimens grown at low temperature (2 ∘C), the effects of light are smaller, with a 1.4 mol % MgCO3 increase from low-light (mean = 17 lx) to high-light conditions (mean = 450 lx). At higher (10 ∘C) temperature there was a 1.8 mol % MgCO3 increase from low to high light. It is therefore concluded that site- and possibly specimen-specific temperature calibrations must be applied, to account for effects of light when generating Clathromorphum-derived temperature calibrations.

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44

LaDouceur, Elise E. B., Linda A. Kuhnz, Christina Biggs, Alicia Bitondo, Megan Olhasso, Katherine L. Scott, and Michael Murray. "Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy." Journal of Marine Science and Engineering 9, no. 8 (August 6, 2021): 848. http://dx.doi.org/10.3390/jmse9080848.

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Sea pigs (Scotoplanes spp.) are deep-sea dwelling sea cucumbers of the phylum Echinodermata, class Holothuroidea, and order Elasipodida. Few reports are available on the microscopic anatomy of these deep-sea animals. This study describes the histologic findings of two, wild, male and female Scotoplanes sp. collected from Monterey Bay, California. Microscopic findings were similar to other holothuroids, with a few notable exceptions. Sea pigs were bilaterally symmetrical with six pairs of greatly enlarged tube feet arising from the lateral body wall and oriented ventrally for walking. Neither a rete mirabile nor respiratory tree was identified, and the large tube feet may function in respiration. Dorsal papillae protrude from the bivium and are histologically similar to tube feet with a large, muscular water vascular canal in the center. There were 10 buccal tentacles, the epidermis of which was highly folded. Only a single gonad was present in each animal; both male and female had histologic evidence of active gametogenesis. In the male, a presumed protozoal cyst was identified in the aboral intestinal mucosa, and was histologically similar to previous reports of coccidians. This work provides control histology for future investigations of sea pigs and related animals using bright field microscopy.

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45

Palter, Jaime B., M. Susan Lozier, and Kara L. Lavender. "How Does Labrador Sea Water Enter the Deep Western Boundary Current?" Journal of Physical Oceanography 38, no. 5 (May 1, 2008): 968–83. http://dx.doi.org/10.1175/2007jpo3807.1.

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Abstract Labrador Sea Water (LSW), a dense water mass formed by convection in the subpolar North Atlantic, is an important constituent of the meridional overturning circulation. Understanding how the water mass enters the deep western boundary current (DWBC), one of the primary pathways by which it exits the subpolar gyre, can shed light on the continuity between climate conditions in the formation region and their downstream signal. Using the trajectories of (profiling) autonomous Lagrangian circulation explorer [(P)ALACE] floats, operating between 1996 and 2002, three processes are evaluated for their role in the entry of Labrador Sea Water in the DWBC: 1) LSW is formed directly in the DWBC, 2) eddies flux LSW laterally from the interior Labrador Sea to the DWBC, and 3) a horizontally divergent mean flow advects LSW from the interior to the DWBC. A comparison of the heat flux associated with each of these three mechanisms suggests that all three contribute to the transformation of the boundary current as it transits the Labrador Sea. The formation of LSW directly in the DWBC and the eddy heat flux between the interior Labrador Sea and the DWBC may play leading roles in setting the interannual variability of the exported water mass.

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46

Bucković, Damir, Maja Martinuš, Duje Kukoč, Blanka Tešović, and Ivan Gušić. "High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)." Geologica Carpathica 61, no. 1 (February 1, 2010): 29–38. http://dx.doi.org/10.2478/v10096-009-0042-z.

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High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)The upper part of the Middle Coniacian/Santonian-Middle Campanian deep-water Dol Formation of the island of Brač is composed of countless fine-grained allodapic intercalations deposited in an intraplatform trough. Within the studied section 13 beds can be distinguished, each defined by its lower part built up of dark grey limestone with abundance of branched, horizontally to subhorizontally oriented burrows, and the upper part, in which the light grey to white limestone contains larger burrows, rarely branched, showing no preferential orientation. The lower, dark grey, intensively bioturbated levels are interpreted as intervals formed during high-frequency sea-level highstands, while the upper, light grey-to-white levels are interpreted as intervals formed during the high-frequency sea-level lowstands. Cyclic alternation of these two intervals within the fine-grained allodapic beds is interpreted as the interaction between the amount of carbonate production on the platform margin and the periodicity and intensity of shedding and deposition in the distal part of toe-of-slope environment, which is governed by Milankovitch-band high frequency sea-level changes.

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47

Arndt, S., and M. Nicolaus. "Seasonal cycle and long-term trend of solar energy fluxes through Arctic sea ice." Cryosphere 8, no. 6 (November 28, 2014): 2219–33. http://dx.doi.org/10.5194/tc-8-2219-2014.

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Abstract. Arctic sea ice has not only decreased in volume during the last decades, but has also changed in its physical properties towards a thinner and more seasonal ice cover. These changes strongly impact the energy budget, and might affect the ice-associated ecosystems. In this study, we quantify solar shortwave fluxes through sea ice for the entire Arctic during all seasons. To focus on sea-ice-related processes, we exclude fluxes through open water, scaling linearly with sea ice concentration. We present a new parameterization of light transmittance through sea ice for all seasons as a function of variable sea ice properties. The maximum monthly mean solar heat flux under the ice of 30 × 105 Jm−2 occurs in June, enough heat to melt 0.3 m of sea ice. Furthermore, our results suggest that 96% of the annual solar heat input through sea ice occurs during only a 4-month period from May to August. Applying the new parameterization to remote sensing and reanalysis data from 1979 to 2011, we find an increase in transmitted light of 1.5% yr−1 for all regions. This corresponds to an increase in potential sea ice bottom melt of 63% over the 33-year study period. Sensitivity studies reveal that the results depend strongly on the timing of melt onset and the correct classification of ice types. Assuming 2 weeks earlier melt onset, the annual transmitted solar radiation to the upper ocean increases by 20%. Continuing the observed transition from a mixed multi-year/first-year sea ice cover to a seasonal ice cover results in an increase in light transmittance by an additional 18%.

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48

JOKELA-MÄÄTTÄ, MIRKA, TEEMU SMURA, ANNA AALTONEN, PETRI ALA-LAURILA, and KRISTIAN DONNER. "Visual pigments of Baltic Sea fishes of marine and limnic origin." Visual Neuroscience 24, no. 3 (May 2007): 389–98. http://dx.doi.org/10.1017/s0952523807070459.

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Absorbance spectra of rods and some cones were measured by microspectrophotometry in 22 fish species from the brackish-water of the Baltic Sea, and when applicable, in the same species from the Atlantic Ocean (3 spp.), the Mediterranean Sea (1 sp.), or Finnish fresh-water lakes (9 spp.). The main purpose was to study whether there were differences suggesting spectral adaptation of rod vision to different photic environments during the short history (<104years) of postglacial isolation of the Baltic Sea and the Finnish lakes. Rod absorbance spectra of the Baltic subspecies/populations of herring (Clupea harengus membras), flounder (Platichthys flesus), and sand goby (Pomatoschistus minutus) were all long-wavelength-shifted (9.8, 1.9, and 5.3 nm, respectively, at the wavelength of maximum absorbance, λmax) compared with their truly marine counterparts, consistent with adaptation for improved quantum catch, and improved signal-to-noise ratio of vision in the Baltic light environment. Judged by the shape of the spectra, the chromophore was pure A1 in all these cases; hence the differences indicate evolutionary tuning of the opsin. In no species of fresh-water origin did we find significant opsin-based spectral shifts specific to the Baltic populations, only spectral differences due to varying A1/A2 chromophore ratio in some. For most species, rod λmaxfell within a wavelength range consistent with high signal-to-noise ratio of vision in the spectral conditions prevailing at depths where light becomes scarce in the respective waters. Exceptions were sandeels in the Baltic Sea, which are active only in bright light, and all species in a “brown” lake, where rod λmaxlay far below the theoretically optimal range.

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49

Kudryavtseva, Elena, Marina Kravchishina, Larisa Pautova, Igor Rusanov, Dmitry Glukhovets, Alexander Shchuka, Ivan Zamyatin, et al. "Sea Ice as a Factor of Primary Production in the European Arctic: Phytoplankton Size Classes and Carbon Fluxes." Journal of Marine Science and Engineering 11, no. 11 (November 8, 2023): 2131. http://dx.doi.org/10.3390/jmse11112131.

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The seasonally ice-covered marine region of the European Arctic has experienced warming and sea ice loss in the last two decades. During expeditions in August 2020 and 2021, new data on size-fractioned primary production (PP), chlorophyll a concentration, phytoplankton biomass and composition and carbon fixation rates in the dark were obtained in the marginal ice zone (MIZ) of the Barents Sea, Nansen Basin and Greenland Sea to better understand the response of Arctic ecosystems to ongoing climate changes. Four different situations were observed in the study region: (i) a bloom of the large-cell diatom Podosira glacialis, whose biomass was trapped in a strong halocline at the edge of a dense ice cover; (ii) a bloom of the chain-like colonies of Thalassiosira diatoms on the shelf in mixed waters in fields of shallow ice that could be supported by “fresh” elements in the polynya condition, as well as by terrestrial run-off and drifting ices; at the late stage, this bloom was accompanied by intensive growth of Phaeocystis pouchetti; (iii) dominance of small-cell phytoplankton under weakened stratification and the significant influence of the Atlantic water, depleted of microelements and silicates; (iv) dominance of dinoflagellates of eutrophic water in the contact zone between the water masses of Arctic origin and Atlantic origin in clear water under conditions of increased light intensity. The >10 µm phytoplankton cell size group increased its relative contribution to PP as a response to stratification, light and nutrient load associated with sea ice conditions. Small phytoplankton with sizes < 2 µm formed the basis of total PP in the MIZ regardless of the state of the sea ice.

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La Mantia, Francesco Paolo, Marilena Baiamonte, Stefania Santangelo, Roberto Scaffaro, and Maria Chiara Mistretta. "Influence of Different Environments and Temperatures on the Photo-Oxidation Behaviour of the Polypropylene." Polymers 15, no. 1 (December 24, 2022): 74. http://dx.doi.org/10.3390/polym15010074.

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The photo-oxidation of polypropylene at two different temperatures and in three different environments—air, distilled water and sea water—has been followed as a function of the irradiation time. The photo-oxidation kinetic is dramatically dependent on the amount of oxygen available for the oxidation reactions and on the temperature. While the photo-oxidation is very fast in air, the degradation is much slower in the two aqueous media. The degradation in sea water is slightly slower than in distilled water. In all cases, the degradation kinetic increases remarkably with the temperature. This behavior has been attributed to the lower oxygen availability for the oxidation reactions of the polymers. The light difference of the degradation kinetic between the two aqueous media depends on the small difference of the oxygen concentration at the test temperatures of 40 and 70 °C. At the latter temperature, the difference between the degradation kinetic in distilled water and sea water is still less important because increasing the temperature decreases the solubility of the oxygen, and it tends to became very similar in both samples of water.

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Journal articles on the topic 'Light in sea-water'

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