Pub Date : 2020-01-20DOI: 10.4236/ojms.2020.101003
A. H. Aberrhaman, L. A. Lrhorfi, B. Bouhaddioui, R. Bengueddour
The diversity of phytoplankton communities in marine waters depends on the environmental, physical, chemical and biological factors in which they occur. The aim of our work is to determine the effect of certain physicochemical parameters on the proliferation of five planktonic taxa (1: Alexandrium 2: Dinophysis 3: Gymnodinum; 4: Pseudonitzschia; 5: Proocentrum) identified on the sites of Mehdia and Moulay Bousselham, Gharb of Moroccobetween 2017 and 2018. The results confirm the presence of these toxic taxa in both sites but with different densities. The ACP has allowed separating two distinct groups with coefficients of determination of more than 70%. Indeed, the first group concerning the site of Mehdia, it is characterized by an abundance of the taxa of Gymnodium and Pseudoni, which prefers salt water and oxygenated, thus important phosphate and nitrate levels. Moreover, unlike the temperature factor. However, the second group concerning the Moulay Bousselham site is located on the positive side of the axis, essentially characterized by moderately high temperatures. These conditions are favorable for the Dinophysis, Alexandrum and Proocentrum taxa. This trend makes it possible to classify the Moulay Bousselham site as a risk zone. In light of these results, the authorities of all stakeholders in the sector must increase efforts to overcome this constraint.
{"title":"Study of the Effect of Certain Physicochemical Parameters on the Distribution of Toxic Planktonic Taxa in Two Oceanic Sites Mehdia and Moulay Bousselham, Rabat Sale Kenitra Region, Morocco","authors":"A. H. Aberrhaman, L. A. Lrhorfi, B. Bouhaddioui, R. Bengueddour","doi":"10.4236/ojms.2020.101003","DOIUrl":"https://doi.org/10.4236/ojms.2020.101003","url":null,"abstract":"The diversity of phytoplankton communities in marine \u0000waters depends on the environmental, physical, chemical and biological factors \u0000in which they occur. The aim of our work is to determine the effect of certain \u0000physicochemical parameters on the proliferation of five planktonic taxa (1: \u0000Alexandrium 2: Dinophysis 3: Gymnodinum; 4: Pseudonitzschia; 5: Proocentrum) \u0000identified on the sites of Mehdia and Moulay Bousselham, Gharb of \u0000Moroccobetween 2017 and 2018. The results confirm the presence of these toxic \u0000taxa in both sites but with different densities. The ACP has allowed separating \u0000two distinct groups with coefficients of determination of more than 70%. \u0000Indeed, the first group concerning the site of Mehdia, it is characterized by \u0000an abundance of the taxa of Gymnodium and Pseudoni, which prefers salt water and oxygenated, thus important phosphate \u0000and nitrate levels. Moreover, unlike the temperature factor. However, the \u0000second group concerning the Moulay Bousselham site is located on the positive \u0000side of the axis, essentially characterized by moderately high temperatures. \u0000These conditions are favorable for the Dinophysis, Alexandrum and Proocentrum \u0000taxa. This trend makes it possible to classify the Moulay Bousselham site as a \u0000risk zone. In light of these results, the authorities of all stakeholders in \u0000the sector must increase efforts to overcome this constraint.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46871357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.4236/ojms.2020.103013
J. Pingel, A. Harrison
It is well known that whales in captivity suffer from dorsal fin bending. However, the mechanisms behind this change are poorly understood. Humans can suffer from similar symptoms either after a period of immobilization or after suffering a brain lesion. Therefore, we here speculate whether the bent dorsal fins are reflecting contracture development in whales.
{"title":"Contracture Development in Whales","authors":"J. Pingel, A. Harrison","doi":"10.4236/ojms.2020.103013","DOIUrl":"https://doi.org/10.4236/ojms.2020.103013","url":null,"abstract":"It is well known that whales in captivity suffer from dorsal fin bending. However, the mechanisms behind this change are poorly understood. Humans can suffer from similar symptoms either after a period of immobilization or after suffering a brain lesion. Therefore, we here speculate whether the bent dorsal fins are reflecting contracture development in whales.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70365601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.4236/ojms.2020.101002
S. Nitonye, Prince Ugboga
The analysis of the effectiveness and efficiency of Vernomia amydalina (VA) solution as an inhibitor on offshore pipeline and Ship materials (Steel) was carried out with the preparation of the specimen and the VA solution. The specimens were kept in a workable state and the VA Solution (inhibitor) prepared from 1200 g of bitter leaf was plucked, weighed and crushed separately. 600 cl of water was added to each of the crushed leaves. The mixture was put in a filter cloth and squeezed with hand to filter out the active concentration ingredients responsible for corrosion inhibition, which produced a 2 M concentration of VA extract solution. After the experiment was carried out the specimen was air-dried and weighed to determine the corrosion rate and weight loss. This was followed by the determination of the inhibitor efficiency at the different hours and at different percentage/concentration of the VA solution on the specimen. Results were obtained for different hours and at different percentage (0%, 5%, 10%, 15%, 20% and 25% inhibitor)/concentration of the VA solution and graphs plotted. It was observed that at the first week of exposure to corrosive medium there was a substantial reduction in weight of coupons but over the next three weeks there was a gradual decline in weight loss and the corrosion rate reduced evenly. It can be said that the percentage of inhibitor to corrosive medium is insufficient. From the graphs plotted, the inhibitor efficiency is considered high when the concentration of the VA solution is high, which implies a right percentage of inhibitor needs to be administered to obtain good efficiency of the solution. Hence as the weeks go by it was clear that the inhibitor was gradually losing its effectiveness. This means that inhibitors need to be added at regular intervals to sustain the effectiveness of the inhibitor. It is also of vital interest to apply the right concentration of inhibitor since CR increases at high concentrations and temperature. This process did not take into consideration moving water.
{"title":"Analysis of the Effectiveness and Efficiency of the VA Solution on Offshore Pipelines and Ship Materials","authors":"S. Nitonye, Prince Ugboga","doi":"10.4236/ojms.2020.101002","DOIUrl":"https://doi.org/10.4236/ojms.2020.101002","url":null,"abstract":"The analysis of the effectiveness and efficiency of Vernomia amydalina (VA) solution as an inhibitor on offshore pipeline and Ship materials (Steel) was carried out with the preparation of the specimen and the VA solution. The specimens were kept in a workable state and the VA Solution (inhibitor) prepared from 1200 g of bitter leaf was plucked, weighed and crushed separately. 600 cl of water was added to each of the crushed leaves. The mixture was put in a filter cloth and squeezed with hand to filter out the active concentration ingredients responsible for corrosion inhibition, which produced a 2 M concentration of VA extract solution. After the experiment was carried out the specimen was air-dried and weighed to determine the corrosion rate and weight loss. This was followed by the determination of the inhibitor efficiency at the different hours and at different percentage/concentration of the VA solution on the specimen. Results were obtained for different hours and at different percentage (0%, 5%, 10%, 15%, 20% and 25% inhibitor)/concentration of the VA solution and graphs plotted. It was observed that at the first week of exposure to corrosive medium there was a substantial reduction in weight of coupons but over the next three weeks there was a gradual decline in weight loss and the corrosion rate reduced evenly. It can be said that the percentage of inhibitor to corrosive medium is insufficient. From the graphs plotted, the inhibitor efficiency is considered high when the concentration of the VA solution is high, which implies a right percentage of inhibitor needs to be administered to obtain good efficiency of the solution. Hence as the weeks go by it was clear that the inhibitor was gradually losing its effectiveness. This means that inhibitors need to be added at regular intervals to sustain the effectiveness of the inhibitor. It is also of vital interest to apply the right concentration of inhibitor since CR increases at high concentrations and temperature. This process did not take into consideration moving water.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70365793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.4236/ojms.2020.103009
A. Firoozfar, Morteza Askari Ziarati, Nima Asghari, Navid Alavi, Nikoo Ghorbanian
Underground tunneling is one of the alternative solutions to diminish traffic congestion in large cities. One of the most important effects of tunneling is the displacement of the ground surface, the settlement around the tunnel, and the variation in earthquake acceleration. The performance and behavior of underground structures have been studied by several researchers, but the impact of tunnel excavation on earthquake records and its effects on structures above the ground level have received less attention. This research emphasizes changes of earthquake acceleration at the ground level, structural response and Fourier spectrum by excavating a horseshoe tunnel. Results show that digging a horseshoe tunnel will change the characteristics of the earthquake record at ground level.
{"title":"Alteration of Ground Motion Acceleration at Ground Level Due to Tunnel Excavation","authors":"A. Firoozfar, Morteza Askari Ziarati, Nima Asghari, Navid Alavi, Nikoo Ghorbanian","doi":"10.4236/ojms.2020.103009","DOIUrl":"https://doi.org/10.4236/ojms.2020.103009","url":null,"abstract":"Underground tunneling is one of the alternative solutions to diminish traffic congestion in large cities. One of the most important effects of tunneling is the displacement of the ground surface, the settlement around the tunnel, and the variation in earthquake acceleration. The performance and behavior of underground structures have been studied by several researchers, but the impact of tunnel excavation on earthquake records and its effects on structures above the ground level have received less attention. This research emphasizes changes of earthquake acceleration at the ground level, structural response and Fourier spectrum by excavating a horseshoe tunnel. Results show that digging a horseshoe tunnel will change the characteristics of the earthquake record at ground level.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70365867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sequence of the ribosomal RNA gene (rDNA) plays an important role in species identification and phylogenetic analysis. However, the only published full-length sequence of a ribosomal gene of green algae is that of Ulva mutabilis. In this study, we amplified the full-length sequence of each ribosomal gene unit of the ribosomal gene of Blidingia minima. The full-length sequence of the ribosomal gene in Blidingia minima is 8676 bp, including the 1759 bp 18S rDNA, 576 bp internal transcribed spacer (ITS) + 5.8S rDNA, 3282 bp 28S rDNA, and 3059 bp intergenic spacer (IGS) region. We then carried out a series of genetic analyses based on the ITS and IGS sequences, to verify whether IGS sequences are useful for studying the genetic diversity of green algae from different locations. We amplified the IGS sequences of Blidingia minima from 10 different locations in the Yellow Sea. Multiple alignments of the IGS sequences of samples from these 10 different sites revealed varying degrees of base differences, and comparative analysis of the ITS sequences revealed that our amplified species was classified as Blidingia minima and distinct from other green algae. In conclusion, our full-length amplified ribosomal gene provides useful information to enrich the data on green algae ribosomal genes and provides an effective molecular marker for the analysis of the interspecies and intraspecies relationships of Blidingia minima.
{"title":"The Amplification and Application of Ribosomal RNA (rDNA) Gene Sequences of Blidingia minima (Chlorophyta, Blidingia)","authors":"Yuan-yun Ao, Weijie Shen, Anxiang Yuan, Yih-Huei Yin, Yuan He, S. Shen","doi":"10.4236/ojms.2020.103014","DOIUrl":"https://doi.org/10.4236/ojms.2020.103014","url":null,"abstract":"The sequence of the ribosomal RNA gene (rDNA) plays an important role in species identification and phylogenetic analysis. However, the only published full-length sequence of a ribosomal gene of green algae is that of Ulva mutabilis. In this study, we amplified the full-length sequence of each ribosomal gene unit of the ribosomal gene of Blidingia minima. The full-length sequence of the ribosomal gene in Blidingia minima is 8676 bp, including the 1759 bp 18S rDNA, 576 bp internal transcribed spacer (ITS) + 5.8S rDNA, 3282 bp 28S rDNA, and 3059 bp intergenic spacer (IGS) region. We then carried out a series of genetic analyses based on the ITS and IGS sequences, to verify whether IGS sequences are useful for studying the genetic diversity of green algae from different locations. We amplified the IGS sequences of Blidingia minima from 10 different locations in the Yellow Sea. Multiple alignments of the IGS sequences of samples from these 10 different sites revealed varying degrees of base differences, and comparative analysis of the ITS sequences revealed that our amplified species was classified as Blidingia minima and distinct from other green algae. In conclusion, our full-length amplified ribosomal gene provides useful information to enrich the data on green algae ribosomal genes and provides an effective molecular marker for the analysis of the interspecies and intraspecies relationships of Blidingia minima.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70365689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-12DOI: 10.4236/ojms.2020.101001
Layla Al-Shaer, A. Bloch, M. Draud, B. Baumann, M. Itzkowitz
The decline in herbivorous fishes is an important contributing factor to the degradation of coral reefs, because their reduction contributes to macro algae overgrowth, which can have harmful effects on corals. Herbivorous fish often form mixed-species groups to locate foraging sites and for defense. The movements and compositions of these groups are dependent on the relative numbers of different species present. Some species, such as the striped parrotfish (Scarus iserti) and ocean surgeonfish (Acanthurus bahianus), serve as core species that lead mixed-species groups. Others, such as the redband (Sparisoma aurofrenatum) and stoplight parrotfishes (Sparisoma viride), follow core species as their associates. Despite the potential importance and abundance of mixed-species groups on reefs, little attention has been given to their composition and movements. Our intent was to determine whether the social dynamics of mixed-species groups in Jamaica were similar to those of Grand Cayman. The overall sizes of mixed-species groups were smaller in Grand Cayman. Focal striped parrotfish in Grand Cayman formed smaller groups, changed composition less, and moved less frequently than in Jamaica. Although probably more abundant than striped parrotfish, the ocean surgeonfish in Grand Cayman did not function as a core species but rather attached themselves as associates to the smaller striped parrotfish groups. Redband parrotfish moved less often in Grand Cayman, and appeared to be more dependent on striped parrotfish groups than stoplight parrotfish. While previous studies on herbivorous reef fish have shown that changes in foraging patterns can change with location, perhaps related to structural heterogeneity and resource distribution, this study illustrates that social interactions between common members of mixed-species groups also change. We suggest that the intra and interspecific social interactions in Grand Cayman are less attuned to finding erratically located high quality resources than those in Jamaica. Other plausible explanations are also considered.
{"title":"Comparisons of Group-Size, Composition and Movement of Herbivorous Reef Fish in Jamaica and Grand Cayman Island","authors":"Layla Al-Shaer, A. Bloch, M. Draud, B. Baumann, M. Itzkowitz","doi":"10.4236/ojms.2020.101001","DOIUrl":"https://doi.org/10.4236/ojms.2020.101001","url":null,"abstract":"The \u0000decline in herbivorous fishes is an important contributing factor to the \u0000degradation of coral reefs, because their reduction contributes to macro algae \u0000overgrowth, which can have harmful effects on corals. Herbivorous fish often \u0000form mixed-species groups to locate foraging sites and for defense. The \u0000movements and compositions of these groups are dependent on the relative numbers \u0000of different species present. Some species, such as the striped parrotfish (Scarus iserti) and ocean surgeonfish (Acanthurus bahianus), serve as core \u0000species that lead mixed-species groups. Others, such as the redband (Sparisoma aurofrenatum) and stoplight \u0000parrotfishes (Sparisoma viride), follow \u0000core species as their associates. Despite the potential importance and abundance \u0000of mixed-species groups on reefs, little attention has been given to their \u0000composition and movements. Our intent was to determine whether the social \u0000dynamics of mixed-species groups in Jamaica were similar to those of Grand \u0000Cayman. The overall sizes of mixed-species groups were smaller in Grand Cayman. \u0000Focal striped parrotfish in Grand Cayman formed smaller groups, changed \u0000composition less, and moved less frequently than in Jamaica. Although probably \u0000more abundant than striped parrotfish, the ocean surgeonfish in Grand Cayman \u0000did not function as a core species but rather attached themselves as associates \u0000to the smaller striped parrotfish groups. Redband parrotfish moved less often \u0000in Grand Cayman, and appeared to be more dependent on striped parrotfish groups \u0000than stoplight parrotfish. While previous studies on herbivorous reef fish have \u0000shown that changes in foraging patterns can change with location, perhaps \u0000related to structural heterogeneity and resource distribution, this study \u0000illustrates that social interactions between common members of mixed-species \u0000groups also change. We suggest that the intra and interspecific social \u0000interactions in Grand Cayman are less attuned to finding erratically located \u0000high quality resources than those in Jamaica. Other plausible explanations are \u0000also considered.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49400233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Samon, F. M. Gouissi, D. Adje, Koudjodé Simon Abahi, Christelle Madina Tchaou, Jeff Gildas Antoine Okoya, Zoulkanerou Orou Piami, Midogbo Pierre Gnohossou, G. Omoniyi, C. Piscart
This study focuses on the biodiversity of macroinvertebrates of the Affon River. To reach this goal, eight stations were sampled and physical parameters such as temperature, pH, conductivity, transparency, depth, total dissolved solids (TDS) and dissolved oxygen were measured. Chemical parameters such as ammonium nitrite and phosphate were measured in the laboratory. We identified 9755 macroinvertebrates belonging to 4 classes, 14 orders, and 49 families. Chironomidae were the most abundant family whereas other sensitive insect’s orders such as Ephemeroptera, Trichoptera, and Plecoptera were rarely found, suggesting a poor water quality of the Affon River. The principal components analysis yielded three groups of stations: the first group (Teneka 2 and 3) characterized by high values of ammonium and phosphate and low values of conductivity and TDS; the second group (Taneka 1 and Kolokonde 1) with low values of pH, transparency, ammonium and phosphate; and the third group of stations (Kolokonde 2, Kpebouko1, Kpebouko 2, and Affon) marked by high values of conductivity, TDS, transparency, depth and temperature. This study is a crucial step for any management and monitoring of the Affon River.
{"title":"Abundance and Distribution of Macroinvertebrates of the Affon River in Bénin","authors":"O. Samon, F. M. Gouissi, D. Adje, Koudjodé Simon Abahi, Christelle Madina Tchaou, Jeff Gildas Antoine Okoya, Zoulkanerou Orou Piami, Midogbo Pierre Gnohossou, G. Omoniyi, C. Piscart","doi":"10.4236/ojms.2019.94013","DOIUrl":"https://doi.org/10.4236/ojms.2019.94013","url":null,"abstract":"This study focuses on the biodiversity of macroinvertebrates \u0000of the Affon River. To reach this goal, eight stations were sampled and \u0000physical parameters such as temperature, pH, conductivity, transparency, depth, \u0000total dissolved solids (TDS) and dissolved oxygen were measured. Chemical parameters \u0000such as ammonium nitrite and phosphate were measured in the laboratory. We \u0000identified 9755 macroinvertebrates belonging to 4 classes, 14 orders, and 49 \u0000families. Chironomidae were the most abundant family whereas other sensitive \u0000insect’s orders such as Ephemeroptera, Trichoptera, and Plecoptera were rarely \u0000found, suggesting a poor water quality of the Affon River. The principal \u0000components analysis yielded three groups of stations: the first group (Teneka 2 \u0000and 3) characterized by high values of ammonium and phosphate and low values of \u0000conductivity and TDS; the second group (Taneka 1 and Kolokonde 1) with low \u0000values of pH, transparency, ammonium and phosphate; and the third group of \u0000stations (Kolokonde 2, Kpebouko1, Kpebouko 2, and Affon) marked by high values \u0000of conductivity, TDS, transparency, depth and temperature. This study is a crucial step for any management and monitoring of the Affon \u0000River.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70365072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The maritime industry is currently facing the challenges of adopting new technologies and operational practices with stricter international, national and local rules in order to reduce exhaust gas emissions from ships. The most objective of regulations introduced and presented by the Worldwide Sea Organization such as International Maritime Organization (IMO) and the US Environmental Protection Agency (EPA) is to lessen the commitment shipping makes to worldwide and local discharges. This paper analyzes emissions from marine engines and the process of waste exhaust gas formation and provides a summary of the emission reduction technologies to satisfy MARPOL NOx tier III and EPA tier IV rules. The results showed the possibility of achieving a valuable emission reduction percentage if future diesel engines are equipped with pre-treatment, internal-treatment and/or post-treatment techniques. Economics impact for medium and low speed for category 3 marine diesel engines is also presented.
{"title":"A Review and Economic Analysis of Different Emission Reduction Techniques for Marine Diesel Engines","authors":"M. Issa, H. Ibrahim, A. Ilinca, M. Hayyani","doi":"10.4236/OJMS.2019.93012","DOIUrl":"https://doi.org/10.4236/OJMS.2019.93012","url":null,"abstract":"The maritime industry is currently facing the challenges of adopting new technologies and operational practices with stricter international, national and local rules in order to reduce exhaust gas emissions from ships. The most objective of regulations introduced and presented by the Worldwide Sea Organization such as International Maritime Organization (IMO) and the US Environmental Protection Agency (EPA) is to lessen the commitment shipping makes to worldwide and local discharges. This paper analyzes emissions from marine engines and the process of waste exhaust gas formation and provides a summary of the emission reduction technologies to satisfy MARPOL NOx tier III and EPA tier IV rules. The results showed the possibility of achieving a valuable emission reduction percentage if future diesel engines are equipped with pre-treatment, internal-treatment and/or post-treatment techniques. Economics impact for medium and low speed for category 3 marine diesel engines is also presented.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42057523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An ecological zonation of phytoplankton was determined from its normalized spectral absorption shape (aphn) during the summers of 2001-02-03 off the west coast of Baja California. In the first two seasons, the highest abundances of the main taxonomic groups of phytoplankton were detected towards the coastal stations, but for 2003, diatoms showed higher abundances towards the oceanic region. The ecological provinces (Pv) were the footprint of the zonation in the structure of the phytoplankton community; likewise, it was observed that the spectral shape was independent of the chlorophyll-a (mg·m-3). The effect of coastal upwelling south of Vizcaino Bay favored the increase of phytoplankton cells. However, the composition of the community decreased in cells abundance and diversity due to the influence of the phenomenon called El Nino “debil” reported to the south of the California Current for the years 2002-03.
{"title":"Ecological Zonation of Phytoplankton and Biomass Based on Bio-Optical Parameters off Baja California during Three Summer Seasons","authors":"Sánchez-Pérez Elvia Denisse, Millán-Núñez Eduardo","doi":"10.4236/OJMS.2019.93010","DOIUrl":"https://doi.org/10.4236/OJMS.2019.93010","url":null,"abstract":"An \u0000ecological zonation of phytoplankton was determined from its normalized \u0000spectral absorption shape (aphn) \u0000during the summers of 2001-02-03 off the west coast of Baja California. In the \u0000first two seasons, the highest abundances of the main taxonomic groups of \u0000phytoplankton were detected towards the coastal stations, but for 2003, diatoms \u0000showed higher abundances towards the oceanic region. The ecological provinces \u0000(Pv) were the footprint of the zonation in the structure of the phytoplankton \u0000community; likewise, it was observed that the spectral shape was independent of \u0000the chlorophyll-a (mg·m-3). The effect of coastal upwelling south of Vizcaino \u0000Bay favored the increase of phytoplankton cells. However, the composition of \u0000the community decreased in cells abundance and diversity due to the influence \u0000of the phenomenon called El Nino “debil” reported to the south of the \u0000California Current for the years 2002-03.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42682364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Facetotecta is among the lesser known groups in the world ocean. The present study recorded two types of Facetotecta in the Andaman Sea, off Andaman Islands. These two types of Facetotecta were observed during the period of August 2015, July 2016 and October 2017 and identified as Type I Hansenocaris corvinae and Type IX Hansenocaris leucadea. However, the cursory analysis suggested that the Type IX is a new type of Facetotecta and named it as Type XII Hansenocaris portblairenae sp. (nov). This finding suggests that this Facetotecta observation is the first report in the Andaman Sea, as well as in the Indian Ocean Region.
{"title":"Identification of Y-Nauplii (Facetotecta) in Andaman Sea, India","authors":"V. Swathi, P. Mohan","doi":"10.4236/OJMS.2019.93011","DOIUrl":"https://doi.org/10.4236/OJMS.2019.93011","url":null,"abstract":"The Facetotecta \u0000is among the lesser known groups in the world ocean. The present study recorded \u0000two types of Facetotecta in the Andaman Sea, off Andaman Islands. These two \u0000types of Facetotecta were observed during the period of August 2015, July 2016 \u0000and October 2017 and identified as Type I Hansenocaris \u0000corvinae and Type IX Hansenocaris \u0000leucadea. However, the cursory analysis suggested that the Type IX is a new \u0000type of Facetotecta and named it as Type XII Hansenocaris portblairenae sp. (nov). This finding suggests that \u0000this Facetotecta observation is the first report in the Andaman Sea, as well as \u0000in the Indian Ocean Region.","PeriodicalId":65849,"journal":{"name":"海洋科学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42344175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：