Multivariate approach to evaluate the factors controlling the phytoplankton abundance and diversity along the coastal waters of Diu, northeastern Arabian Sea

Abstract The composition of seawater plays a very significant role in determining the severity of corrosion process in marine assets. The influential contributors to the general and pitting corrosions in marine structures include temperature, dissolved oxygen (DO), salinity, PH, chlorides, pollutants, nutrients, and microbiological activities in seawater. The Cu-Ni (90/10) alloy is increasingly used in marine applications such as heat exchangers and marine pipelines because of its excellent corrosion resistant properties. Despite the significant advancements in corrosion shielding procedures, complete stoppage of corrosion induced metal loss, especially under rugged marine environments, is practically impossible. The selection of appropriate metal thickness is merely a multifaceted decision because of the high variability in operating conditions and associated corrosion rate in various seawater bodies across the globe. The present research study aims to analyze the early phase of corrosion behavior of Cu-Ni (90/10) alloy in open-sea conditions as well as in pollutant-rich coastal waters of the Arabian Sea. Test samples were placed under natural climatic conditions of selected sites, followed by the mass loss and corrosion rate evaluation. The corrosion rate in the pollutant-rich coastal waters was around five times higher than in the natural seawater. A case study on marine condenser (fitted with of Cu-Ni 90/10 alloy tubes) is presented, and a risk-based inspection (RBI) plan is developed to facilitate equipment designers, operators, and maintainers to consider the implications of warm and polluted seawater on equipment reliability, service life, and subsequent health inspection/ maintenance.

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The marine planktonic dinoflagellate Tripos: 60 years of species-level distributions in Australian waters

Australian Systematic Botany ◽

10.1071/sb19043 ◽

2020 ◽

Author(s):

Gustaaf Hallegraeff ◽

Ruth Eriksen ◽

Claire Davies ◽

Anita Slotwinski ◽

Felicity McEnnulty ◽

...

Keyword(s):

Coastal Waters ◽

Arabian Sea ◽

Light And Electron Microscopy ◽

Species Level ◽

Freshwater Species ◽

Careful Attention ◽

Tropical Waters ◽

Australian Species ◽

The Past ◽

Water Species

We reviewed 15572 Australian species-level records of the marine planktonic dinoflagellate Tripos Bory (formerly Ceratium Schrank, a genus now restricted to freshwater species). The genus is represented by over 50 species and numerous varieties and forms in Australian tropical, subtropical and temperate marine waters and the Southern Ocean. There exists considerable plasticity in the morphology of many species, which has confounded species delimitations and created uncertainty around their spatial distributions. We newly illustrate by light and electron microscopy the rarely reported Tripos hundhausenii (Schröd.) Hallegr. & Huisman comb. nov. first described from the Arabian Sea, but increasingly being observed in Sydney coastal waters. A large number of Tripos species are widely distributed in temperate, subtropical and tropical waters and their distributions have remained remarkably stable in Australian waters over the past 60–80 years. By contrast, we identified a narrow group of warm-water species, including T. belone (Cleve) F.Gómez, T. cephalotus (Lemmerm.) F.Gómez, T. dens (Ostenf. & E.J.Schmidt) F.Gómez, T. digitatus (F.Schütt) F.Gómez, T. gravidus (Gourret) F.Gómez, T. incisus (G.Karst.) F.Gómez, T. paradoxides (Cleve) F.Gómez and T. praelongus (Lemmerm.) F.Gómez, that are commonly encountered off Sydney, rarely found down to Eden and Batemans Bay or Bass Strait, but occasionally occur as far south as King Island and Maria Island, Tasmania. These rare tropical Tripos species are carried southward by the East Australian and Leeuwin Currents and deserve careful attention in monitoring for future range expansions, changes in seasonality or upwelling or incursion of deep tropical waters.

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Estimation of inherent optical properties using quasi-analytical algorithm along the coastal waters of southeast Arabian Sea

Ocean Dynamics ◽

10.1007/s10236-019-01287-x ◽

2019 ◽

Vol 69 (8) ◽

pp. 925-937

Author(s):

Kumaraswami Munnooru ◽

Sisir Kumar Dash ◽

Gijjapu Durga Rao ◽

Ramu Karri ◽

Vinjamuri Ranga Rao

Keyword(s):

Optical Properties ◽

Coastal Waters ◽

Arabian Sea ◽

Inherent Optical Properties ◽

Analytical Algorithm

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Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea

ICES Journal of Marine Science ◽

10.1093/icesjms/fsq191 ◽

2011 ◽

Vol 68 (4) ◽

pp. 745-750 ◽

Cited By ~ 5

Author(s):

Harilal B. Menon ◽

Nutan Sangekar ◽

Aneesh Lotliker ◽

Krishnaswamy Krishna Moorthy ◽

Ponnumani Vethamony

Keyword(s):

Spatial Variability ◽

Optical Thickness ◽

Coastal Waters ◽

Arabian Sea ◽

Aerosol Optical Thickness ◽

Aerosol Size Distribution ◽

Wave Radiation ◽

Transfer Model ◽

Eastern Arabian Sea

Abstract Menon, H. B., Sangekar, N., Lotliker, A., Krishna Moorthy, K., and Vethamony, P. 2011. Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea. – ICES Journal of Marine Science, 68: 745–750. Data from the ocean-colour monitor (OCM) on board the Indian Remote Sensing Satellite P4 were used to analyse the spatial and temporal distribution of aerosol optical thickness (AOT) over the coastal and offshore waters of the eastern Arabian Sea. Zero water-leaving radiance from the near infrared (NIR) region was assumed for oceanic (open ocean) waters, because of the absorption of long-wave radiation by water molecules. As this assumption fails in coastal waters, it was necessary to correct for water-leaving radiance and sun glint to the NIR bands. The aerosol size-distribution parameter (α) was derived from a relationship between two NIR bands. The Ångström turbidity parameter (β) was obtained using an algorithm relating in situ hand-held, sun-photometer measurements and aerosol radiance (La) at 490 nm. The relationship between β and La (490) was derived with a sensitivity analysis, using a calibrated radiative transfer model. AOTs were retrieved for each pixel of 500 nm. The algorithm's performance was tested by comparing OCM-derived AOT values with in situ AOT and MODIS-derived values. Aerosol maps thus generated from January to December 2005 demonstrate the potential of this new retrieval method for producing AOT climatology from OCM data over coastal waters.

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