This paper describes investigations of the internal waves in the Andaman Sea using Moderate Resolution Imaging Spectroradiometer(MODIS)imagery over the period of June 2010 to May 2016.Results of the spatial and tempor...This paper describes investigations of the internal waves in the Andaman Sea using Moderate Resolution Imaging Spectroradiometer(MODIS)imagery over the period of June 2010 to May 2016.Results of the spatial and temporal distribution,generation sources and propagation characteristics of internal waves are presented.The statistical analysis shows that internal waves can be observed in almost the entire area of the Andaman Sea.Most internal waves are observed in the northern,central and southern regions of the Andaman Sea.A significant number of internal waves between 7°N and 9°N in the East Indian Ocean are also observed.Internal waves can be observed year-round in the Andaman Sea,while most of internal waves are observed between February and April,with a maximum frequency of 15.03%in March.The seasonal distribution of the internal waves shows that the internal waves have mostly been observed in the dry season(February to April),and fewer internal waves are observed in the rainy season(May to October).The double peak distribution for the occurrence frequency of internal waves is found.With respect to the lunar influence,more internal waves are observed after the spring tide,which implies the spring tide may play an important role in internal wave generation in the Andaman Sea.Generation sources of internal waves are explored based on the propagation characteristics of internal waves.The results indicate that six sources are located between the Andaman Islands and the Nicobar Islands,and one is located in the northern Andaman Sea.Four regions with active internal wave phenomenon in the Andaman Sea were presented during the MODIS survey,and the propagation speed of internal waves calculated based on the semidiurnal generation period is smaller than the results acquired from pairs of the images with short time intervals.展开更多
火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的...火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的驱动因素,以安达曼海南部的海洋钻孔ADM-C1为研究材料,对其全新世以来的炭屑记录进行深入分析,并综合安达曼海周边地区其余的5个炭屑记录,重建了全新世以来安达曼海周边地区火灾活动的演变过程。研究表明,尽管点火、火灾天气和植被组成在各地不尽相同,导致火灾发生频率在区域和地方范围有所不同,但在广泛的气候变化背景下,全新世安达曼海周边各地的火事件发生频率变化具有广泛同步性。全新世安达曼海周边的火灾活动发生频率受到区域性植被和降水变化影响,并最终受控于印度夏季风强度的变化。与末次冰消期相比,12.0~9.0 ka BP安达曼海周边区域火灾活动的发生频率呈下降趋势,反映了印度夏季风降水逐步增加以及木本植物含量逐渐上升的区域环境;9.0~5.0 ka BP较低的区域火灾活动发生频率同时受到较高的印度夏季风降水量和区域木本植物含量的制约;5.0 ka BP后高频的区域火灾活动更多反映了印度夏季风降水的降低。此外,研究结果还表明全新世安达曼海周边区域火灾活动发生频率与厄尔尼诺—南方涛动强度、印度洋偶极子位相和热带辐合带位置的变化相关。展开更多
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...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.展开更多
The characteristics of currents and tidal currents in the Andaman Sea（AS） are studied during the second half of2016 using observed data from a moored acoustic Doppler current profiler（ADCP） deployed at 8.6°N,...The characteristics of currents and tidal currents in the Andaman Sea（AS） are studied during the second half of2016 using observed data from a moored acoustic Doppler current profiler（ADCP） deployed at 8.6°N, 95.6°E.During the observation period, the mean flow is 5–10 cm/s and largely southward. The root mean square and kinetic energies of the low and high frequency flows, which are divided by a cutoff period of 5 d, are at the same level, indicating their identical importance to the total current. A power spectrum analysis shows that intraseasonal oscillations, a tidal-related semilunar month signal, a semidiurnal tidal signal and periods of 3–4 d are prominent. The barocliny of an eddy kinetic energy is stronger than the mean kinetic energy, both of which are the strongest on the bottom and the weakest at 70 m depth. Residual currents are largely southward（northward） during the summer（winter） monsoon season. Two striking peaks of the southward flow cause the 80 d period of meridional currents. The first peak is part of a large-scale circulation, which enters the AS through the northern channel and exits through the southern channel, and the second peak is part of a local vortex. The 40 d oscillation of the zonal current is forced by geostrophic variations attributed to local and equatorial remote forcing. The tidal current is dominated by semidiurnal constituents, and among these, M2 and N2 are the top two largest major axes. Moreover, astronomical tidal constituents MM and MSF are also significant. Diurnal constituents are weak and shallow water tides are ignorable. The aims are to introduce the new current data observed in the AS and to provide initial insights for the tidal and residual currents in the Andaman Sea.展开更多
Andaman and Nicobar Islands, the gastropod diversity is high, due to the majority of shores are rocky. The wet rocky shore promotes algal growth, which is ultimate for feeding ground for gastropod growth and developme...Andaman and Nicobar Islands, the gastropod diversity is high, due to the majority of shores are rocky. The wet rocky shore promotes algal growth, which is ultimate for feeding ground for gastropod growth and development leading to more diversity. The global warming, anthropogenic activities, industrial and domestic pollution, etc., have accelerated the loss of coastal and marine biodiversity components over the last few decades which has been of great concern. However, except global warming, the other factors were of least concern with reference to Andaman and Nicobar Islands biodiversity due to a pristine environment. Therefore, exploration of biodiversity in these islands is essential to create a baseline data for record and future research. Four locations of south to north Andaman Islands which represented Carbyns Cove from south Andaman, Rangat and Mayabunder from the Middle Andaman and Diglipur from the North Andaman were selected for this study. Gastropoda species were collected for a period of one year in three prevailing seasons of Andaman and Nicobar Islands. They are South West Monsoon (SW monsoon), North East Monsoon (NE Monsoon) and Non Rainy Seasons (NR Seasons). The present study of gastropods distribution in the South, Middle and North Andaman groups of Islands suggested that there are 71 species belonging to 52 genus and 33 families. At any one of the time and any one of the locations, only one occurrence was noticed for 38 species and remaining 33 species were overlapping with respect to stations and seasons. Evaluation of the cluster suggested that Cluster A (NR season in Carbyns Cove) and Cluster B (NE and SW Monsoon in Mayabunder) as a separate entity among the 12 combinations of stations and seasons due to their species representation. It was also concluded that out of 71 studied species, 3 species were not reported till date in these Island environment and 2 species from any other parts of India.展开更多
Box jellyfish Chiropsoides buitendijki from the coastal zone along the Andaman Sea, southwestern Thailand are characterized by a box-shaped body with unilateral branched tentacles and lack of interradial furrows. Tent...Box jellyfish Chiropsoides buitendijki from the coastal zone along the Andaman Sea, southwestern Thailand are characterized by a box-shaped body with unilateral branched tentacles and lack of interradial furrows. Tentacular banding was first reported in the present study with 1-3-2-3-2-3-2-3-1 patterns （1-major band, 2-thicker minor band and 3-thinner minor band）. The DNA sequences of 18 S ribosomal RNA genes indicated that the specimen examined were genetically similar to C. buitendijki that was previously identified from the Nam Bor Bay, Phuket, Thailand, and distinct to the other known taxa in the order Chirodropida. In addition, a significant genetic divergence based on 16S mitochondrial gene was observed within the C. buitendijki samples. This indicates a population genetic differentiation but needs further confirmation.展开更多
In this study, we assess coral health by detecting the severity of coral diseases and compromised health states on massive Porites. Field surveys are conducted at twenty-two sites covering the eastern, inner and weste...In this study, we assess coral health by detecting the severity of coral diseases and compromised health states on massive Porites. Field surveys are conducted at twenty-two sites covering the eastern, inner and western Gulf of Thailand as well as the Andaman Sea during 2010–2015. A total of nine coral diseases and signs of compromised health are observed in the waters of Thailand, consisting of pigmentation responses(pink lines, pink patches,pink spots and pink borers), white syndromes(white patches, white bands and ulcerative white spots), growth anomalies, and unusual bleaching patterns. The highest severity of all observed coral diseases and signs of compromised health are found at Ko Khang Khao in the inner Gulf of Thailand, while that observed in the Andaman Sea is relatively low. Composition of the diseases vary across the study sites. Four groups of study sites,in which there is an 80% similarity of diseases or signs of compromised health composition, are clustered and detected based on the Bray-Curtis similarity. The canonical analysis of principal coordinates reveal that most study sites in the Gulf of Thailand, especially the inner Gulf of Thailand, tend to show a high severity of the diseases. The association of disease severity and composition and the level of human impact are also detected.The study sites located near the shores and/or the areas with intensive tourism tend to have higher human impact, especially on poor water quality, which may be linked to the higher severity and composition of coral diseases and signs of compromised health in the Gulf of Thailand. Fish bites are also observed in many study sites.The severity of fish bites in the Gulf of Thailand is much lower compared to the Andaman Sea. Ko Rawi exhibits the highest severity, following by Ko Surin Nua and Ko Butang. The study sites within marine national park boundaries have a significantly higher severity of fish bites than those outside of the marine national park boundaries. This study suggests that higher coral diseases and 展开更多
基金The National Key Research and Development Program of China under contract No.2017YFC1405102the National Natural Science Foundation of China under contract No.61471136the Global Change and Air-Sea Interaction Program of China under contract No.GASI-02-IND-YGST2-04
文摘This paper describes investigations of the internal waves in the Andaman Sea using Moderate Resolution Imaging Spectroradiometer(MODIS)imagery over the period of June 2010 to May 2016.Results of the spatial and temporal distribution,generation sources and propagation characteristics of internal waves are presented.The statistical analysis shows that internal waves can be observed in almost the entire area of the Andaman Sea.Most internal waves are observed in the northern,central and southern regions of the Andaman Sea.A significant number of internal waves between 7°N and 9°N in the East Indian Ocean are also observed.Internal waves can be observed year-round in the Andaman Sea,while most of internal waves are observed between February and April,with a maximum frequency of 15.03%in March.The seasonal distribution of the internal waves shows that the internal waves have mostly been observed in the dry season(February to April),and fewer internal waves are observed in the rainy season(May to October).The double peak distribution for the occurrence frequency of internal waves is found.With respect to the lunar influence,more internal waves are observed after the spring tide,which implies the spring tide may play an important role in internal wave generation in the Andaman Sea.Generation sources of internal waves are explored based on the propagation characteristics of internal waves.The results indicate that six sources are located between the Andaman Islands and the Nicobar Islands,and one is located in the northern Andaman Sea.Four regions with active internal wave phenomenon in the Andaman Sea were presented during the MODIS survey,and the propagation speed of internal waves calculated based on the semidiurnal generation period is smaller than the results acquired from pairs of the images with short time intervals.
文摘火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的驱动因素,以安达曼海南部的海洋钻孔ADM-C1为研究材料,对其全新世以来的炭屑记录进行深入分析,并综合安达曼海周边地区其余的5个炭屑记录,重建了全新世以来安达曼海周边地区火灾活动的演变过程。研究表明,尽管点火、火灾天气和植被组成在各地不尽相同,导致火灾发生频率在区域和地方范围有所不同,但在广泛的气候变化背景下,全新世安达曼海周边各地的火事件发生频率变化具有广泛同步性。全新世安达曼海周边的火灾活动发生频率受到区域性植被和降水变化影响,并最终受控于印度夏季风强度的变化。与末次冰消期相比,12.0~9.0 ka BP安达曼海周边区域火灾活动的发生频率呈下降趋势,反映了印度夏季风降水逐步增加以及木本植物含量逐渐上升的区域环境;9.0~5.0 ka BP较低的区域火灾活动发生频率同时受到较高的印度夏季风降水量和区域木本植物含量的制约;5.0 ka BP后高频的区域火灾活动更多反映了印度夏季风降水的降低。此外,研究结果还表明全新世安达曼海周边区域火灾活动发生频率与厄尔尼诺—南方涛动强度、印度洋偶极子位相和热带辐合带位置的变化相关。
文摘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.
基金The National Key Research and Development Program of China under contract No.2017YFC1405100the National Natural Science Foundation of China under contract No.41406034the Basic Scientific Research Fund for National Public Institutes of China under contract No.GY0215P05
文摘The characteristics of currents and tidal currents in the Andaman Sea（AS） are studied during the second half of2016 using observed data from a moored acoustic Doppler current profiler（ADCP） deployed at 8.6°N, 95.6°E.During the observation period, the mean flow is 5–10 cm/s and largely southward. The root mean square and kinetic energies of the low and high frequency flows, which are divided by a cutoff period of 5 d, are at the same level, indicating their identical importance to the total current. A power spectrum analysis shows that intraseasonal oscillations, a tidal-related semilunar month signal, a semidiurnal tidal signal and periods of 3–4 d are prominent. The barocliny of an eddy kinetic energy is stronger than the mean kinetic energy, both of which are the strongest on the bottom and the weakest at 70 m depth. Residual currents are largely southward（northward） during the summer（winter） monsoon season. Two striking peaks of the southward flow cause the 80 d period of meridional currents. The first peak is part of a large-scale circulation, which enters the AS through the northern channel and exits through the southern channel, and the second peak is part of a local vortex. The 40 d oscillation of the zonal current is forced by geostrophic variations attributed to local and equatorial remote forcing. The tidal current is dominated by semidiurnal constituents, and among these, M2 and N2 are the top two largest major axes. Moreover, astronomical tidal constituents MM and MSF are also significant. Diurnal constituents are weak and shallow water tides are ignorable. The aims are to introduce the new current data observed in the AS and to provide initial insights for the tidal and residual currents in the Andaman Sea.
文摘Andaman and Nicobar Islands, the gastropod diversity is high, due to the majority of shores are rocky. The wet rocky shore promotes algal growth, which is ultimate for feeding ground for gastropod growth and development leading to more diversity. The global warming, anthropogenic activities, industrial and domestic pollution, etc., have accelerated the loss of coastal and marine biodiversity components over the last few decades which has been of great concern. However, except global warming, the other factors were of least concern with reference to Andaman and Nicobar Islands biodiversity due to a pristine environment. Therefore, exploration of biodiversity in these islands is essential to create a baseline data for record and future research. Four locations of south to north Andaman Islands which represented Carbyns Cove from south Andaman, Rangat and Mayabunder from the Middle Andaman and Diglipur from the North Andaman were selected for this study. Gastropoda species were collected for a period of one year in three prevailing seasons of Andaman and Nicobar Islands. They are South West Monsoon (SW monsoon), North East Monsoon (NE Monsoon) and Non Rainy Seasons (NR Seasons). The present study of gastropods distribution in the South, Middle and North Andaman groups of Islands suggested that there are 71 species belonging to 52 genus and 33 families. At any one of the time and any one of the locations, only one occurrence was noticed for 38 species and remaining 33 species were overlapping with respect to stations and seasons. Evaluation of the cluster suggested that Cluster A (NR season in Carbyns Cove) and Cluster B (NE and SW Monsoon in Mayabunder) as a separate entity among the 12 combinations of stations and seasons due to their species representation. It was also concluded that out of 71 studied species, 3 species were not reported till date in these Island environment and 2 species from any other parts of India.
基金China-ASEAN Maritime Cooperation Fundthe Tropical Marine Ecosystem Collaborative Study(TiME)of the Thailand-China Joint Laboratory for Climate and Marine Ecosystem+2 种基金the Public Science and Technology Research Funds Projects of Ocean under contract No.201505004the fund from Phuket Marine Biological Centerthe Miscellaneous Contribution No.60 from Phuket Marine Biological Center
文摘Box jellyfish Chiropsoides buitendijki from the coastal zone along the Andaman Sea, southwestern Thailand are characterized by a box-shaped body with unilateral branched tentacles and lack of interradial furrows. Tentacular banding was first reported in the present study with 1-3-2-3-2-3-2-3-1 patterns （1-major band, 2-thicker minor band and 3-thinner minor band）. The DNA sequences of 18 S ribosomal RNA genes indicated that the specimen examined were genetically similar to C. buitendijki that was previously identified from the Nam Bor Bay, Phuket, Thailand, and distinct to the other known taxa in the order Chirodropida. In addition, a significant genetic divergence based on 16S mitochondrial gene was observed within the C. buitendijki samples. This indicates a population genetic differentiation but needs further confirmation.
基金The budget for research promotion from the Government of Thailand to Ramkhamhaeng University
文摘In this study, we assess coral health by detecting the severity of coral diseases and compromised health states on massive Porites. Field surveys are conducted at twenty-two sites covering the eastern, inner and western Gulf of Thailand as well as the Andaman Sea during 2010–2015. A total of nine coral diseases and signs of compromised health are observed in the waters of Thailand, consisting of pigmentation responses(pink lines, pink patches,pink spots and pink borers), white syndromes(white patches, white bands and ulcerative white spots), growth anomalies, and unusual bleaching patterns. The highest severity of all observed coral diseases and signs of compromised health are found at Ko Khang Khao in the inner Gulf of Thailand, while that observed in the Andaman Sea is relatively low. Composition of the diseases vary across the study sites. Four groups of study sites,in which there is an 80% similarity of diseases or signs of compromised health composition, are clustered and detected based on the Bray-Curtis similarity. The canonical analysis of principal coordinates reveal that most study sites in the Gulf of Thailand, especially the inner Gulf of Thailand, tend to show a high severity of the diseases. The association of disease severity and composition and the level of human impact are also detected.The study sites located near the shores and/or the areas with intensive tourism tend to have higher human impact, especially on poor water quality, which may be linked to the higher severity and composition of coral diseases and signs of compromised health in the Gulf of Thailand. Fish bites are also observed in many study sites.The severity of fish bites in the Gulf of Thailand is much lower compared to the Andaman Sea. Ko Rawi exhibits the highest severity, following by Ko Surin Nua and Ko Butang. The study sites within marine national park boundaries have a significantly higher severity of fish bites than those outside of the marine national park boundaries. This study suggests that higher coral diseases and
