Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay,Northern South China Sea     

Liao  Jianzu  Xu  Jie  Yuan  Xiangcheng  Liang  Yuxian  Guo  Yajuan  Zhou  Weihua  Huang  Hui  Liu  Sheng  Long  Aimin 《Ocean Science Journal》2019,54(4):581-593

Ocean Science Journal - The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of...  相似文献   

Integration of hyperspectral and LiDAR data for mapping small water bodies     

《International Journal of Applied Earth Observation and Geoinformation》2020

Inland water bodies are globally threatened by environmental degradation and climate change. On the other hand, new water bodies can be designed during landscape restoration (e.g. after coal mining). Effective management of new water resources requires continuous monitoring; in situ surveys are, however, extremely time-demanding. Remote sensing has been widely used for identifying water bodies. However, the use of optical imagery is constrained by accuracy problems related to the difficulty in distinguishing water features from other surfaces with low albedo, such as tree shadows. This is especially true when mapping water bodies of different sizes. To address these problems, we evaluated the potential of integrating hyperspectral data with LiDAR (hereinafter “integrative approach”). The study area consisted of several spoil heaps containing heterogeneous water bodies with a high variability of shape and size. We utilized object-based classification (Support Vector Machine) based on: (i) hyperspectral data; (ii) LiDAR variables; (iii) integration of both datasets. Besides, we classified hyperspectral data using pixel-based approaches (K-mean, spectral angle mapper). Individual approaches (hyperspectral data, LiDAR data and integrative approach) resulted in 2–22.4 % underestimation of the water surface area (i.e, omission error) and 0.4–1.5 % overestimation (i.e., commission error).The integrative approach yielded an improved discrimination of open water surface compared to other approaches (omission error of 2 % and commission error of 0.4 %). We also evaluated the success of detecting individual ponds; the integrative approach was the only one capable of detecting the water bodies with both omission and commission errors below 10 %. Finally, the assessment of misclassification reasons showed a successful elimination of shadows in the integrative approach. Our findings demonstrate that the integration of hyperspectral and LiDAR data can greatly improve the identification of small water bodies and can be applied in practice to support mapping of restoration process.  相似文献   

Current Levels of Artificial Radioisotopes in Biota from the Arctic Continental Shelf (2013–2018)     

Matishov  G. G.  Ilyin  V. G.  Usyagina  I. S.  Valuyskaya  D. A.  Kirillova  E. E. 《Doklady Earth Sciences》2020,494(1):730-734

Doklady Earth Sciences - This paper analyzes data on the concentration and dynamics of 137Cs and 90Sr in marine organisms on the Arctic shelf under modern conditions (2013–2018). It is shown...  相似文献   

The petrology,geochronology and tectono-magmatic setting of igneous rocks in the Suckling-Dayman metamorphic core complex,Papua New Guinea     

《Gondwana Research》2020

Southeastern Papua New Guinea has hosted magmatism throughout the Cenozoic, with the latest phase being concurrent with active extension in the Woodlark Rift. There, the Suckling-Dayman metamorphic core complex (SDMCC) has exhumed middle-crustal rocks in the past few million years along a still-active low-angle normal fault, the Mai'iu Fault. Uplift of the SDMCC has exposed metasedimentary and metaigneous rocks of Late Cretaceous-Pleistocene age that record an evolution from oceanic spreading to subduction, to collision, and finally to subduction-inversion and extensional exhumation. We present new petrographic, whole-rock geochemical and geochronologic (zircon U–Pb LA-ICP-MS) data from the SDMCC to reconstruct its long-term evolution. The dominant footwall-lithology of the SDMCC, the Goropu Metabasalt, has a MORB composition. Detrital zircons from metasedimentary beds intercalated with these basalts yield U–Pb-based maximum estimates for deposition of ~103 and ~72 Ma, suggesting a Late Cretaceous spreading age of the oceanic protolith. Bulk compositions of low-grade tholeiitic meta-gabbroic and -tonalitic rocks (Yau Igneous Complex) that intrude the Goropu Metabasalt reveal both enriched and depleted light rare earth element patterns. Zircon U–Pb ages from the Yau Igneous Complex range between ~60 and ~57 Ma, providing a minimum age for the formation of the Goropu Metabasalt. Much younger syn-extensional granitoids in the mafic footwall of the SDMCC have calc-alkaline to high-K compositions and U–Pb ages on zircon between ~3.7 and ~2.0 Ma. Our data indicate that the Mai'iu Fault had re-activated a Paleogene thrust as an extensional detachment fault by 3.7 ± 0.2 Ma. U–Pb ages of detrital zircons in modern streams draining the footwall of the SDMCC essentially reflect the ages revealed by the Paleocene and Plio-Pleistocene intrusions. Xenocrystic zircons in the Plio-Pleistocene granitoids imply that the crust underlying the metabasaltic carapace of the SDMCC consists chiefly of Australian-continent derived sedimentary rocks.  相似文献   

Distribution of Polychaetes in the Laptev Sea and New Siberian Shoal and Its Relation with Environmental Factors     

Syomin  V. L.  Zimina  O. L. 《Oceanology》2020,60(3):316-330

Oceanology - In this paper, the distribution of polychaetes in the Laptev Sea and New Siberian shoal is analyzed based on 115 bottom trawl samples taken in August–October 2014. Polychaetes...  相似文献   

Faecal indicator bacteria in New Zealand freshwater fish: a pilot study     

Sarah Coxon  Jon S Harding  Brent Gilpin 《新西兰海洋与淡水研究杂志》2019,53(3):470-479

Recent studies have suggested that poikilothermic animals, such as fish, may represent a previously overlooked source of the faecal indicator bacteria (FIB) used for the assessment of water quality. However, quantitative studies of FIB in poikilotherms are scarce. We investigated the presence of FIB in the faeces of five freshwater fish species. E. coli and enterococci were detected in 71 and 76% of faecal samples, respectively. Concentrations were highly variable, with maximum concentrations (2.1?×?10⁴ E. coli and 1.3?×?10⁶ enterococci per gram of faecal material) up to four orders of magnitude higher than present in the water column. FIB were not detected in faecal samples from marine fish. Our findings suggest that FIB ingested from the environment may be capable of replication within the fish gut, making fish a potential source and transport mechanism for FIB in New Zealand freshwaters. This may have implications for water quality monitoring.  相似文献   

Habitability analyses of aquatic bacteria     

Md. Nurul Haider  Masahiko Nishimura  Minoru Ijichi  Ching-chia Yang  Wataru Iwasaki  Kazuhiro Kogure 《Journal of Oceanography》2018,74(2):197-207

Habitability is defined as an ability of an organism to inhabit different environments. Habitability of organisms, however, cannot be inferred from analyses such as a whole genome or community structures. A recently developed database, the MetaMetaDB, gives us information from what kind of environments one particular 16S rRNA sequence data has ever been obtained, and thus enables us to infer the habitability of the bacterium in question. In order to check the applicability of this database to study the habitability of aquatic bacteria, samples collected at two Naka River stations, one estuarine station from Naka River Estuary, two coastal stations at Oarai in Ibaraki Prefecture, Japan and one station in the Kuroshio Current of the western North Pacific were examined. The phylotypes were tracked against the MetaMetaDB and it was reasonably found that the low-salinity stations were dominated by sequences with “freshwater and groundwater”, “human” and “wastewater” habitat identities, while the high-salinity stations were dominated by those with a “marine” identity. The phylotypes of low-salinity stations with a particular habitat identity were absent or rare in the high-salinity stations and vice versa. The MetaMetaDB also showed that sequences of Cyanobacteria or related phylogenetic groups may be present in the human gut, as well as the probable distribution of the relatives (ancestors/descendants/siblings) of some bacteria. These overall findings proved that the MetaMetaDB is useful as a new tool to infer microbial habitability and it gives us new information on the possible origin and ecology of microorganisms in the environments.  相似文献   

Tide-related Changes in mRNA Abundance of Aromatases and Estrogen Receptors in the Ovary and Brain of the Threespot Wrasse <Emphasis Type="Italic">Halichoeres trimaculatus</Emphasis>     

Dae-Ju Oh  Sung-Pyo Hur  Selma Bouchekioua  Yuki Takeuchi  Shingo Udagawa  Neelakanteswar Aluru  Yong-Ju Park  Ji-Gweon Park  Se-Jae Kim  Thomas W. Moon  Mathilakath M. Vijayan  Akihiro Takemura 《Ocean Science Journal》2018,53(2):239-249

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Assessing Cryptic Invasion State: Fine-Scale Genetic Analysis of Ciona savignyi Population in Putative Native Habitat of the Korean Coast     

Yi  Chang Ho  Kim  Won 《Ocean Science Journal》2020,55(1):99-113

The solitary ascidian, Ciona savignyi (Ascidiacea, Enterogona) is a notorious marine invader still expanding its habitat range worldwide. This species is considered native to the North West Pacific, but its indigeneity in Korean coastal waters has been questioned because of outdated taxonomic records and its inhabitation of oceanographically marginal areas. To clarify their cryptic invasion state, 247 individual C. savignyi samples were collected from 12 harbors and marinas on the Korean coast, and a 744 bp region of mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I gene was sequenced and analyzed. Our analyses of population genetic structure and demographic history provided considerable pieces of evidence supporting their long-term establishment on the Korean coasts: differentiated population genetic structure, sequentially arrayed star-shape haplotype network, neutrality test results of past population expansions, and post-glacial colonization pattern of demography. Consequently, we concluded that C. savignyi populations on the Korean Coast are indigenous rather than exotic. These results could be used as reference data for further phylogeo graphic and demographic studies of problematic Ciona species, and to clarify and resolve similar cryptic invasion states of the other Korean coastal marine organisms. This study is the first to resolve the cryptic in vasion state of Korean marine organisms using genetic analysis.

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两种造礁石珊瑚对海水酸化和溶解有机碳加富的响应*     

郭亚娟  周伟华  袁翔城  廖健祖  江雷  黄晖 《热带海洋学报》2018,37(1):57-63

文章选择鹿回头近岸海域常见的板叶角蜂巢珊瑚(Favites complanata)和十字牡丹珊瑚(Pavona decussata)为研究对象, 采用室内连续培养的方法, 探究两种不同造礁石珊瑚对酸化和溶解有机碳(DOC)加富的响应。结果表明: 酸化(pH 7.6)并不会影响两种珊瑚的钙化速率和生长速率; 但DOC加富(524.03±78.42μmol•L^-1)使两种珊瑚的钙化速率分别降低67%和47%、生长速率降低59%和40%。当二者共同作用时, 两种珊瑚的钙化速率降低30%和11%、生长速率降低46%和59%, 大多没有DOC单独作用时强烈, 表现出一定的拮抗作用。两种珊瑚共生虫黄藻叶绿素荧光指数(F_v/F_m)均升高后降低, 板叶角蜂巢珊瑚F_v/F_m最先降低。实验表明, 这两种珊瑚虽然对海洋酸化的敏感度不高, 但是对有机物加富有不同的响应, 板叶角蜂巢珊瑚更为敏感, 可能导致这两种珊瑚在未来环境变化中有不同命运。  相似文献