Corals and coral-reef ecosystems have been known to be extremely sensitive to environmental pollution, which effects on growth and calcification of their skeletons. Diffused phosphate dust during loading and shipment ...Corals and coral-reef ecosystems have been known to be extremely sensitive to environmental pollution, which effects on growth and calcification of their skeletons. Diffused phosphate dust during loading and shipment in seawater was found to cause serious impacts on corals by inhibiting calcification in their skeletons. Calcium concentrations in cultured fragments of coral Stylophora pistillata from Phosphate Terminal (PT) site in the Jordanian Gulf of Aqaba were investigated and compared with fragments from the same colony cultured in the Marine Science Station (MSS) site as marine protected area. Energy Disperse X-rays (EDX) spectroscopy and Scanning Electron Microscopy (SEM) were employed to determine the elemental composition of coral fragments and identify their microstructural characteristics, respectively. EDX results showed that coral samples from the Phosphate Terminal (PT) site were poorly mineralized with significantly low concentrations of calcium which were only about 12% of those from the MSS control site. Moreover, higher amounts of O and C in the elemental analysis of corals from the PT site indicated domination of organic matrix content in their skeleton which is typical for corals under phosphate pollution stress. This result was in accordance with the SEM images of the PT samples which exhibited alteration in their microstructure morphology resembling organic matrix as a major constituent, unlike the SEM images from the MSS protected area. These results strongly suggest that phosphate dust which is diffused during exportation through loading and shipping in the Gulf of Aqaba has adverse impacts on corals and marine ecosystem through decreasing calcium mineralization in their skeletons.展开更多
Cultured Stylophora pistillata in Phosphate Loading Berth (PLB) sites in the Jordanian Gulf of Aqaba was investigated using Back-Scatter Scanning Electron (BSE) microscopy and Energy-Disperse X-ray (EDX) to determine ...Cultured Stylophora pistillata in Phosphate Loading Berth (PLB) sites in the Jordanian Gulf of Aqaba was investigated using Back-Scatter Scanning Electron (BSE) microscopy and Energy-Disperse X-ray (EDX) to determine trace elements and calcium concentrations’ distribution within the micrometer scale. Ca, C, and O in addition to six trace elements (Mg, Sr, S, Cl, Ni, and Na) were mapped within the sample cross section. Samples from the PLB were as expected poorly mineralized as previously reported and showed mineralization heterogeneity in the micrometer length scale in the BSE image. In four selected positions within the cross sections, Ca concentration found to range between 0.44 - 1.80 wt% in low-mineralized regions and between 3.99 - 4.66 wt% in mineralized regions. The average calcium concentrations were in accordance to previous study;about 10% of the Ca existed in the same coral species from other coastal sites in the Gulf of Aqaba. This could be attributed to the role of phosphate in inhibition of calcification and enhancement of photosynthesis. Amounts of trace elements in lower Ca concentration positions within the cross section were relatively very low except for chlorine, whereas positions with higher Ca contained amounts of Na and Sr. This study reports remarkable heterogeneity in mineral distribution within the microstructure of the coral Stylophora pistillata under phosphate pollution stress.展开更多
This paper describes for the first time the cornute stylophorans (Echinodermata) in China. The new material came from the Guole Formation of the Furongian (Late Cambrian) in the Guole area of Jingxi, Guangxi Province,...This paper describes for the first time the cornute stylophorans (Echinodermata) in China. The new material came from the Guole Formation of the Furongian (Late Cambrian) in the Guole area of Jingxi, Guangxi Province, South China. These new cornute specimens are preserved in situ and found along with well-preserved trilobites and brachiopods. One new species, Phyllocystis jingxiensis sp. nov., is proposed to accommodate these unusual materials. The new species is defined by the small, heart-shaped theca with the frame composed of ten narrow, smooth and thick marginal plates, three adoral plates and distinctive zygal and aulacophore. Both supracentrals and infracentrals are polygonal-outlined. The marginal plate M1' on the inferior face extends posteriorly to form zygal that possesses a broadened proximal end and the proximal portion joining with the conjunction between M4 and M5 on the inferior face. Aulacophore comprises ten segments at its proximal part and is conical at the middle part (named stylocone). Its distal portion is rather long and bears conspicuous ambulacrum grooves. Tectals are horizontally arranged on superior face and obliquely arranged on inferior face. Both cothurnopore and anal pyramid are vaguely seen on the right anterior corner and the extremity of theca's superior face.展开更多
文摘Corals and coral-reef ecosystems have been known to be extremely sensitive to environmental pollution, which effects on growth and calcification of their skeletons. Diffused phosphate dust during loading and shipment in seawater was found to cause serious impacts on corals by inhibiting calcification in their skeletons. Calcium concentrations in cultured fragments of coral Stylophora pistillata from Phosphate Terminal (PT) site in the Jordanian Gulf of Aqaba were investigated and compared with fragments from the same colony cultured in the Marine Science Station (MSS) site as marine protected area. Energy Disperse X-rays (EDX) spectroscopy and Scanning Electron Microscopy (SEM) were employed to determine the elemental composition of coral fragments and identify their microstructural characteristics, respectively. EDX results showed that coral samples from the Phosphate Terminal (PT) site were poorly mineralized with significantly low concentrations of calcium which were only about 12% of those from the MSS control site. Moreover, higher amounts of O and C in the elemental analysis of corals from the PT site indicated domination of organic matrix content in their skeleton which is typical for corals under phosphate pollution stress. This result was in accordance with the SEM images of the PT samples which exhibited alteration in their microstructure morphology resembling organic matrix as a major constituent, unlike the SEM images from the MSS protected area. These results strongly suggest that phosphate dust which is diffused during exportation through loading and shipping in the Gulf of Aqaba has adverse impacts on corals and marine ecosystem through decreasing calcium mineralization in their skeletons.
文摘Cultured Stylophora pistillata in Phosphate Loading Berth (PLB) sites in the Jordanian Gulf of Aqaba was investigated using Back-Scatter Scanning Electron (BSE) microscopy and Energy-Disperse X-ray (EDX) to determine trace elements and calcium concentrations’ distribution within the micrometer scale. Ca, C, and O in addition to six trace elements (Mg, Sr, S, Cl, Ni, and Na) were mapped within the sample cross section. Samples from the PLB were as expected poorly mineralized as previously reported and showed mineralization heterogeneity in the micrometer length scale in the BSE image. In four selected positions within the cross sections, Ca concentration found to range between 0.44 - 1.80 wt% in low-mineralized regions and between 3.99 - 4.66 wt% in mineralized regions. The average calcium concentrations were in accordance to previous study;about 10% of the Ca existed in the same coral species from other coastal sites in the Gulf of Aqaba. This could be attributed to the role of phosphate in inhibition of calcification and enhancement of photosynthesis. Amounts of trace elements in lower Ca concentration positions within the cross section were relatively very low except for chlorine, whereas positions with higher Ca contained amounts of Na and Sr. This study reports remarkable heterogeneity in mineral distribution within the microstructure of the coral Stylophora pistillata under phosphate pollution stress.
基金the Natural Science Foundation Program of Guangxi (Grant No. 0542005)the Program to Sponsor Teams for Innovation in the Construction of Talent Heighlands in Guangxi Institution of Higher Learning
文摘This paper describes for the first time the cornute stylophorans (Echinodermata) in China. The new material came from the Guole Formation of the Furongian (Late Cambrian) in the Guole area of Jingxi, Guangxi Province, South China. These new cornute specimens are preserved in situ and found along with well-preserved trilobites and brachiopods. One new species, Phyllocystis jingxiensis sp. nov., is proposed to accommodate these unusual materials. The new species is defined by the small, heart-shaped theca with the frame composed of ten narrow, smooth and thick marginal plates, three adoral plates and distinctive zygal and aulacophore. Both supracentrals and infracentrals are polygonal-outlined. The marginal plate M1' on the inferior face extends posteriorly to form zygal that possesses a broadened proximal end and the proximal portion joining with the conjunction between M4 and M5 on the inferior face. Aulacophore comprises ten segments at its proximal part and is conical at the middle part (named stylocone). Its distal portion is rather long and bears conspicuous ambulacrum grooves. Tectals are horizontally arranged on superior face and obliquely arranged on inferior face. Both cothurnopore and anal pyramid are vaguely seen on the right anterior corner and the extremity of theca's superior face.
