Detrital sediments derived from the Philippine Islands are one of the main sources of deep-sea sediments in the western Philippine Sea.However,systematic research on their characteristics and transport mechanisms are ...Detrital sediments derived from the Philippine Islands are one of the main sources of deep-sea sediments in the western Philippine Sea.However,systematic research on their characteristics and transport mechanisms are lacking.We used parametric end-member analysis to quantitatively partition the grain size of detrital sediments in core MD06-3052 from the Bicol Shelf in the western Philippine Sea;three endmembers EMI,EM2,and EM3,whose respective modes were at 2,10,and 45 μm,were separated.We also measured the Sr and Nd isotopic compositions of different size fractions(<4 and >20 μm) of the detrital sediments and the results showed that the detrital sediments mainly originate from the Philippine Islands.Components EMI and EM2 are transported to the Bicol Shelf mainly by surface and bottom currents from the islands,and component EM3 is delivered by gravity flow from the exposed shelf during low sea-level stands.The content of the total detrital fraction and the three end-members,as well as the mass accumulation rates(MARs) of the coarse detritus(EM2 and EM3),were considerably higher during glacial periods(40-14 ka and 150-130 ka) than during other intervals;the glacials corresponded to a low sea level,while the MAR of the fine detritus(EMI) did not increase remarkably during 40-14 ka.We therefore concluded that the input of coarse detritus to the Bicol Shelf from the islands was mainly controlled by sea-level change.Variations of the input of fine-grained detritus(EM1) was influenced not only by sea level but also by ocean currents and regional precipitation.Overall,our results help understand "source-to-sink" processes in the western Pacific marginal seas and their response to global change.展开更多
The paper aimed to determine the true identity of a presumed or commonly believed Sinarapan fish and compare their phylogenetic relationships by using DNA barcoding.The fish samples were collected by researchers from ...The paper aimed to determine the true identity of a presumed or commonly believed Sinarapan fish and compare their phylogenetic relationships by using DNA barcoding.The fish samples were collected by researchers from a fisheries research and development institution in April 2015 from four different lakes of Bicol Region,i.e.,Lakes Buhi,Danao,Manapao and Bato.DNA was extracted using cetyl trimethyl ammonium bromide(CTAB)extraction buffer.The polymerase chain reaction(PCR)profile for the reaction was 94℃for 10 min,followed by 35 cycles of 1 min at 94℃,1 min at 48℃and 1.5 min at 72℃,and a final extension of 10 min at 72℃.The CO 1 region with approximately 650 bp was amplified because of its capability to differentiate taxa.Sequencing was done by Macrogen while phylogenetic analysis was produced using a Molecular Evolutionary Genetics Analysis(MEGA)software version 6.0.The findings showed that CO1 can be used as a DNA marker in molecular identification of the fish samples.Samples from two of the four lakes were successfully sequenced.From basic local alignment search tool(BLAST)results,the maximum parsimony(MP)and neighbor-joining(N J)trees revealed that samples from Lakes Buhi and Bato are not species of Sinarapan but rather species of Leiopotherapon plumbeus and Rhinogobius giurinus,respectively.Furthermore,DNA barcoding is very useful in proving the true identity of unknown samples.展开更多
基金the National Natural Science Foundation of China (Nos.41776065,41576050,41830539)the Basic Scientific Fund for National Public Research Institutes of China (Nos.2019S04,2017Y07)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the Open Fund of Qingdao National Laboratory for Marine Science and Technology (No.QNLM20160RP0205)
文摘Detrital sediments derived from the Philippine Islands are one of the main sources of deep-sea sediments in the western Philippine Sea.However,systematic research on their characteristics and transport mechanisms are lacking.We used parametric end-member analysis to quantitatively partition the grain size of detrital sediments in core MD06-3052 from the Bicol Shelf in the western Philippine Sea;three endmembers EMI,EM2,and EM3,whose respective modes were at 2,10,and 45 μm,were separated.We also measured the Sr and Nd isotopic compositions of different size fractions(<4 and >20 μm) of the detrital sediments and the results showed that the detrital sediments mainly originate from the Philippine Islands.Components EMI and EM2 are transported to the Bicol Shelf mainly by surface and bottom currents from the islands,and component EM3 is delivered by gravity flow from the exposed shelf during low sea-level stands.The content of the total detrital fraction and the three end-members,as well as the mass accumulation rates(MARs) of the coarse detritus(EM2 and EM3),were considerably higher during glacial periods(40-14 ka and 150-130 ka) than during other intervals;the glacials corresponded to a low sea level,while the MAR of the fine detritus(EMI) did not increase remarkably during 40-14 ka.We therefore concluded that the input of coarse detritus to the Bicol Shelf from the islands was mainly controlled by sea-level change.Variations of the input of fine-grained detritus(EM1) was influenced not only by sea level but also by ocean currents and regional precipitation.Overall,our results help understand "source-to-sink" processes in the western Pacific marginal seas and their response to global change.
文摘The paper aimed to determine the true identity of a presumed or commonly believed Sinarapan fish and compare their phylogenetic relationships by using DNA barcoding.The fish samples were collected by researchers from a fisheries research and development institution in April 2015 from four different lakes of Bicol Region,i.e.,Lakes Buhi,Danao,Manapao and Bato.DNA was extracted using cetyl trimethyl ammonium bromide(CTAB)extraction buffer.The polymerase chain reaction(PCR)profile for the reaction was 94℃for 10 min,followed by 35 cycles of 1 min at 94℃,1 min at 48℃and 1.5 min at 72℃,and a final extension of 10 min at 72℃.The CO 1 region with approximately 650 bp was amplified because of its capability to differentiate taxa.Sequencing was done by Macrogen while phylogenetic analysis was produced using a Molecular Evolutionary Genetics Analysis(MEGA)software version 6.0.The findings showed that CO1 can be used as a DNA marker in molecular identification of the fish samples.Samples from two of the four lakes were successfully sequenced.From basic local alignment search tool(BLAST)results,the maximum parsimony(MP)and neighbor-joining(N J)trees revealed that samples from Lakes Buhi and Bato are not species of Sinarapan but rather species of Leiopotherapon plumbeus and Rhinogobius giurinus,respectively.Furthermore,DNA barcoding is very useful in proving the true identity of unknown samples.
