Numerical Simulation of Wintertime Mesoscale Eddies in the East China Sea

A POM based three dimension baroclinic prognostic model in σ coordinate was established to simulate the eddies in the East China Seas wintertime circulation, considering the topography, inflow and outflow on the open boundary, Changjiang runoff, heat, flux, and wind stress on the sea surface. The model results showed that three branches separate from the Kuroshio flow toward the interior of the Yellow Sea, and form three eddies respectively. The middle eddy is centered at 124°37′E,37°00′N,the southern eddy is centered at 124°00′E,35°30′N. The large cyclonic eddy centered at 125°06′E,30°30′N and located southwest of Cheju Island is a closed structure formed by the northeastward flowing Taiwan Warm Current, northwestward flowing Yellow Sea Warm Current and southward flowing coastal current. The Kuroshio intrusion engenders an eddy west of Kyushu Island of Japan. The branching of the Kuroshio is the direct dynamic cause of the formation of this large eddy. Moreover, both the topographic influence and the northward wind prevailing in winter affect the eddy’s formation obviously.

Identification of two Skeletonema costatum-like diatoms by fluorescence in situ hybridization

A harmful algae bloom (HAB) is a dense aggregation of algae in a marine or aquatic environment that can result in significant environmental problems. To forecast the occurrence of HAB, development of a rapid and precise detection method is urgently required. In this study, two Skeletonema costatum-like diatoms (SK-1 and SK-2), were identified morphologically under a light microscope, and detected using fluorescent in situ hybridization (FISH). Strain SK-1 was isolated from a frequently HAB affected area of the East China Sea, and strain SK-2 from an aquatic farm in Qingdao, China. Fluorescent DNA probes were designed that were complementary to the ITS sequence (including 5.8S rDNA) of strain SK-1. After hybridization, strong green fluorescence was observed in cells of strain SK-1 under an epifluorescence microscope; however, no such fluorescence was observed with strain SK-2, which indicates that probes hybridized only the DNA of the target strain, SK-1, in species-specific manner, and that the two strains do not belong to a same species. This finding was confirmed by ITS sequence analysis. The FISH technique used in this study was sensitive, simple, and rapid, and is a promising tool for detecting target HAB species in natural environments.

Two Ultraviolet Radiation Datasets that Cover China

Ultraviolet（UV） radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization＇s measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.

Watershed characteristics and climate factors effect on the temporal variability of mercury in the southern Baltic Sea rivers

Mercury（Hg） is a neurotoxic metal which can enter into the human organism mainly by fish consumption, skin and transpiration. In the coastal zone of the southern Baltic Sea, rivers are the main source of Hg. The Polish region represents the largest proportion of the Baltic Sea catchment and this research included four rivers of the Baltic watershed： the Reda,Zagórska Struga, Kacza and Gizdepka. The samples were collected in the years 2011–2013.Total and particulate Hg concentration in these rivers were measured. Due to intensive rain,deposited mercury on the catchment area was washed out into the riverines water and introduced into the Baltic Sea. Consequently, the load of Hg increased three times.Additionally, the intensive dry atmospheric deposition during heating season caused the increase of the concentration of particulate Hg in the river water even by 85%. The research confirmed the role of the river flow magnitude in the load of mercury introduced into the sea by rivers. Moreover, a high variability of mercury concentration was connected to the additional sources such as the chemicals containing Hg and no municipal sewage system.The analysis of stable isotopes indicated that the SPM contained terrestrial organic matter;however, there was no clear correlation between Hgtot, Corgand Ntotconcentrations and δ13C, δ15N, C/N in particulate matter.