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Marine Science
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This is an Open Access Journal

Open Access journal
ISSN (Print) 2163-2421 - ISSN (Online) 2163-243X
Published by SAP

[105 journals]

Salinity in the Surface of the Indian Ocean
- Abstract: Publication year: 2022Source: Marine Science, Volume 10, Number 1Oldemar de Oliveira Carvalho-JuniorLong-term analysis of salinity can be useful to describe the main mechanisms that operate at the surface of the ocean.Average sea surface salinity (SSS) contour plots for the Indian Ocean are produced based on the NODC_WOA94 data provided by the NOAA/OAR/ESRL PSL. Salinity, together with the independent variables wind, ndff (net-down-fresh-water-flow) and Ekman pumping are included in a multiple regression analysis to define the relative importance of each one of these variables in the physical processes at the surface of the Indian Ocean. The ndff data set is based on COADS (Comprehensive Ocean-Atmosphere Data Set). The wind data is obtained from the Florida State University (FSU). The harmonic terms are considered to be stationary and expressed by Fourier series as a cosine function in which the first and second harmonic terms are multiplied by the maximum amplitude of the variable and added to the mean annual parameter. The salinity contours tend to be zonally orientated away from the coast, while a meridional influence is observed close to the boundaries. A typical zonal pattern of salinity distribution is observed only south of 10°S. Maximum annual amplitude values are observed in the north of the Arabian Sea and the Bay of Bengal. The variability of the annual components is consistent with the distribution of the net-down-freshwater-flow (ndff) contours and wind direction. During the SW Monsoon, the ndff becomes gradually positive towards the east, in the direction of the west coast of India, which results in a peak of maximum salinity in August and decreasing afterwards. During the NE Monsoon, the ndff is negative elsewhere in the Arabian Sea. The annual term plays a dominant role in determining the maximum and minimum salinity observed during August and January, while the semi-annual component provides minor adjustment. The annual component shows the influence of the monsoons through the year, with a high salinity during the NE Monsoon and a secondary peak during the SW Monsoon. Although harmonic analysis can be applied to the study of salinity variability, to identify and quantify the variables related to these areas of large annual and semiannual variability, a multiple regression analysis needs to be applied.
Symbiodinium Distribution Patterns in Millepores in the Caribbean: South
Water Cay, Belize and San Salvador, The Bahamas
- Abstract: Publication year: 2021Source: Marine Science, Volume 9, Number 1Mara Waechter Schwiesow, Allison Moreno Samayoa, Jocelyn Torres, Amanda Leimbach, Glorisette Santiago-Rivera, Craig S. TepperSymbiosis with Symbiodinium (Dinoflagellata, Chromalveolata) plays a major role in the survival of numerous coral species. Different Symbiodinium clades provide their hosts with different physiological advantages. However, much of the research concerning coral-Symbiodinium associations has focused on scleractinian corals, while reef-building Millepores (fire coral) have mostly been ignored. We examined the Millepore-Symbiodinium relationship at two thermally different sites in the Caribbean: San Salvador, The Bahamas and South Water Cay, Belize. Our results indicate that there is a difference in symbiont dominance between the two sites. Millepores residing in the cooler sea surface temperatures (SST) of The Bahamas are Symbiodinium clade B dominant (100%) and are not showing signs of bleaching. However, Belize Millepores experiencing warmer SST are mostly Symbiodinium clade A dominant (72%) and are not showing signs of bleaching. Some clade B dominant Belize Millepores (28%) are showing signs of bleaching. These findings are corroborated by a reversal in symbiont dominance of Belize Millepores residing at deeper depths; most are Symbiodinium clade B dominant (80%) and none of these colonies showed signs of bleaching. Our results appear to correlate with the temperature difference between the two sites, and suggest Belize Millepores may be experiencing thermal stress events more frequently. The relationship between specific Symbiodinium clades and their coral hosts may provide the coral with a mechanism to cope with increased thermal stress due to global warming.
Assessing Water Resource Issues Among States in the US South East Region
- Abstract: Publication year: 2020Source: Marine Science, Volume 8, Number 1E. C. Merem, Y. A. Twumasi, J. Wesley, D. Olagbegi, M. Crisler, C. Romorno, M. Alsarari, P. Isokpehi, A. Hines, G. S. Ochai, E. Nwagboso, S. Fageir, S. LeggettThe US Southeast region is endowed with vast deposits of water resource assets located in numerous states. Considering the growing water use to serve rapidly expanding land uses from agriculture, residential areas, thermoelectric to industrial facilities. Over the years, the demand for water to meet the needs of various sectors in the zone has precipitated increased withdrawals, declining levels in aquifers and sectorial imbalance in the distribution. Accordingly, sectorial imbalance and stress attributed to socio-economic, physical and ecological parameters is now being felt in the areas many considered fully endowed with hydrological assets and less vulnerable to depletion. Beset by the management implications of the trends, various agencies in the zone have stepped up mitigation measures. Notwithstanding the gravity of the challenges and the fact that most studies are still festooned with projected depletion patterns in the US arid West, very little work exists in the literature on the changing patterns in water resource use in the Southeast region using a mix scale model. For that, this research will fill that void by assessing the variabilities in water resource use among some states in the Southeast. With emphasis on the issues, trends, factors, and impacts, the study uses secondary info from major data agencies analyzed by mix scale techniques of descriptive statistics and Geographic Information Systems (GIS) to assess the tendencies. The results point to changes in usage among the sectors in the form of gains and declines, the emergence of hydroelectricity and irrigation as the largest users, the dominance of Florida, regional dependence on surface water sources, evidence of depletion and spatial dispersion of these trends across the states. With these changes attributed to various elements, the paper offered suggestions ranging from water conservation measures, the adoption of efficient polices to the design of a regional hydrological information system.
The Process of Fatigue Analysis on Fixed Metal Offshore Platforms
- Abstract: Publication year: 2017Source: Marine Science, Volume 7, Number 1Sajed Nemati Havigh, Mehdi Behdarvandi AskarOne of the important reasons of fracture in jacket pelatforms that makes the sadenly failure and structual resistanc reduce at long time, is Fatigu phenomena. Because of existence of peridice loads derived by waves, sea current, wind, etc. hence, fatigue analysis is important item in offshore structual design. The known methodes of fatigue analys is published at design codes suche as, API and DNV and ABS and other relavant codes, that are in acceptable relationship whit toghether. This paper will reviwe the fatigue analysis methodes and will tries to present a simple and accurate methode that be according to Persian Gulf candition. Whereas, the most of jacket pelatformes in Persian Gulf, has natural ferequence about less than 3s, that’s wisely to using Deterministic methhode for fatigue analysis. However, the mentioned offshore design codes, offer the Spectural methode for all of environmental condition, although the Spectural methode has more accuracy in comparition whit other methodes, but it’s take larg time to analys and needs to high knowledge of mathmaticul transformation functions, frecuncy-domain analysis and dynamic of structures. And in the end, the paper offers that Persian Gulf’s pelatformes, consider whit Erthquake analys, because, most of pelatformes are in the end part of those useful life time.
Coastline Mobility of Goree Island (Senegal), from 1942 to 2011
- Abstract: Publication year: 2017Source: Marine Science, Volume 7, Number 1Bakhoum P. W., Ndour A., Niang I., Sambou B., Traore V. B., Diaw A. T., Sambou H., Ndiaye M. L.This current study aims to quantify Goree island littoral evolution from 1942 to 2011 in the context of sea level rise. Digital Shoreline Analysis System (DSAS), in ArcGIS software was used to extract shoreline positions based on satellites and aerials photography (1942, 1966 and 2011) and estimate historic rate of change. Rates of change statistics were calculated using End Point Rate (EPR) and Net Shoreline Movement (NMS). In this study, EPR was calculated by dividing NMS by elapsed time between earliest and latest measurements for each transect. Results obtained show that shoreline between 1942 and 1966 retreated (-4m) at an average rate of -0.16m /year, compared an average of -0.06m / year between 1966 and 2011. This dynamic can be interpreted as result of project to preserve and restore Goree island (1979-1981). Slave house, mosque of island, Mariama BA School, and historical museum are the most sector affected by erosion. Analysis of results showed that causes are more natural than anthropic. These results provide coastal erosion specialists with valuable information for warning, prevention and adaptation measures against natural disasters such as flooding.
Investigation of the Effect of the Circular Stands Diameters of Marine
Structures and the Distances between Them on Wave Run-up and Force
- Abstract: Publication year: 2016Source: Marine Science, Volume 6, Number 1Mohammad Ghatarband, Mehdi Behdarvandi AskarDesigning see platform stands has always appealed to a large number of engineers active in the field, because see platforms are one of the most important types of offshore structures for utilization of oil and gas resources. Engineers need to know as much as possible about the forces applied to these stands in order to design them in the best way. The purpose of the research is to be able to study and investigate as far as possible the applied forces and wave run-up at circular stands located in offshore regions. Flow-3D software was used for this purpose and for modeling. It was observed after modeling with different geometries that the highest run-up value occurs at 0.3 meter stand diameter and at stand number 1. Furthermore, the greatest applied force occurs in the state where stand diameter is the largest, and the distance between the stands is the shortest.
Size at First Maturity of Cuttlefish, Sepia latimanus, from North Sulawesi
Waters, Indonesia
- Abstract: Publication year: 2015Source: Marine Science, Volume 5, Number 1Silvester B. Pratasik, Marsoedi, D. Arfiati, D. SetyohadiBiological overfishing could occur from either excessive and immature individual exploitation or habitat destruction. This study was aimed to estimate size at first maturity of cuttlefish, Sepialatimanus, collected from North Sulawesi waters. All samples were measured and observed their maturity level. Based on these data, the dorsal mantle length (DML) at first maturity was assessed for minimum legal size determination. Results showed that the cuttlefish samples had maturity level range from immature to post-spawning conditions, while the size at first maturity was estimated as 16 cm DML. Maximum DML was estimated as 55.53 cm and growth coefficient as 0.248. The deviation of mean DML from maximum dorsal length was also considered to see the population condition.
Local Wisdom Mane’e and Its Impact on Fish Resources and Environment in
Nanusa Islands, North Sulawesi, Indonesia
- Abstract: Publication year: 2015Source: Marine Science, Volume 5, Number 1Emil ReppieMane’e is one of the local wisdoms in coral reef fisheries management that is still being conducted in Nanusa Islands, North Sulawesi, Indonesia. Mane’e means a statement of agreement of local community to perform an activity together and rituals to prepare fishing equipment and carry out fishing operations together on the basis of cooperation, solidarity and unity. But mane'e itself is actually a serial end of a customary law process called Eha, which means as a warning not to do or a ban for all public to take natural resources during certain time. Fishing gear is very traditional, made of forest rope (creeping plant), then joined in a row to around 3-4 km long and wrapped with young coconut leaves. The gear is set circle to a reef flat as location of mane’e in the morning at high tides. Both ends of the rope are pulled toward the coast so the fish could be trapped in the middle of the lagoon at the lowest tide. Mane'e ceremony is conducted at nine sites and each has its own name. Rannesite on Intata Island has been established by the regency government as a tourism icon mane'e festival and open to the public. Mane'e through Eha system' actually has a positive impact on compliance with local communities. But the intervention of outsiders has give negative impact in the form of changes in beliefs and social structure, fishery resources damage and the environment deteriorations.
On the Kolmogorov Spectra in the Field of Nonlinear Wind Waves
- Abstract: Publication year: 2014Source: Marine Science, Volume 4, Number 3Vlad Polnikov, G. UmaThe nature of Kolmogorov spectra formation in the field of nonlinear wind waves are discussed. The currently dominating assertion is that such spectra for wind waves are formed as stationary solutions of the kinetic equation, which describes the conservative nonlinear four-waves resonant interactions. However, this statement here is is refuted by direct numerical calculations of the kinetic integral. Using two independent methods of calculating the kinetic integral for nonlinear surface waves in deep water, it is shown that the theoretical spectra of Kolmogorov type, found by Zakharov and co-authors [4, 7], are not stationary on a limited frequency band. Conditions for the existence of Kolmogorov spectra in real wind waves and possible mechanisms of their formation are discussed.
Paleoecology of Upper Cretaceous Sediments in Central Iran, Kerman
(Bondar-e Bido Section) Based on Ostracods
- Abstract: Publication year: 2014Source: Marine Science, Volume 4, Number 2Bita Ghasem Shirazi, Lida Bakhshandeh, Abdollah YazdiIn order to assess the biological potential of ostracods in response to environmental processes, in this study, the Upper Cretaceous sediments of Bondare Bido Section, has been studied. The study Section is located at 45 km away in South-West direction of the Kerman (Iran). The area between northern latitude 57˚17' 48" and " western longitude 29˚49'44. Due to high sensitivity to environmental changes, the Ostracods are reliable indicators to determine water depth in Upper Cretaceous. On the bases of identified microfossils, the Upper Cretaceous sediments of the study area are Turonian-Maastrichtian in age. These deposits have been biostratigraphically and paleoecologicall point of view evaluated and boundary between stages are determined. Here we report 13 genuses of well preserved ostracods belong to two family Podocopida and Platycopida. The assemblage of ostracods and foraminifera are good indicator of ecological environment during deposition of Cretaceous sediments. The abundance of genus and species of planktonic foraminifera and the presence of some benthic foraminifera and ostracods, may indicate relatively deep and open marine (hemiplegic) environment for these deposits.

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