Incubating green turtle (Chelonia mydas) eggs at constant temperatures: Hatching success, hatchling morphology and post-hatch growth.

Past studies applying constant-temperature incubation of eggs have involved all species of sea turtles, but rarely can we find a single one incubating eggs at three or more temperatures. Here, we incubated green turtle (Chelonia mydas) eggs from Ganquan Island, South China Sea, at five constant temperatures (26, 28, 30, 32 and 34 °C) to determine hatching success, incubation length and hatchling phenotype at each test temperature and temperatures optimal for embryonic development. Temperature affected hatching success, incubation length and all seven examined hatchlings traits, and clutch origin affected three (head length, fore-flipper length and hind-flipper length) of the seven. Hatching success was lowest at 34 °C and none of hatchlings hatched at this temperature was normal and survived over one week. The rate of embryonic development and the rate of post-hatch growth both were lowest at 26 °C. Given that low survival and growth rates can translate into reduced individual fitness, we conclude that both 26 °C and 34 °C are unsuitable for incubation of C. mydas eggs. Post-hatch growth was fastest in hatchlings incubated at 30 °C, and eggs of C. mydas incubated at temperatures around 30 °C are more likely to produce mixed sexes. Accordingly, we conclude that temperatures within the range from 28 °C to 32 °C are generally optimal for embryonic development of C. mydas.

[Soil meso- and micro-fauna community structures in different urban forest types in Shanghai, China.] / 上海市不同类型城市森林中小型土壤动物群落结构特征.

Soil meso- and micro-fauna of four urban forest types in Shanghai were investigated in four months which include April 2014, July 2014, October 2014 and January 2015. A total of 2190 soil fauna individuals which belong to 6 phyla, 15 classes and 22 groups were collected. The dominant groups were Nematoda and Arcari, accounting for 56.0% and 21.8% of the total in terms of individual numbers respectively. The common groups were Enchytraeidae, Rotatoria, Collembola and Hymenoptera and they accounted for 18.7% of the total in terms of individual numbers. There was a significant difference (P<0.05) among soil meso- and micro-fauna density in the four urban forest types and the largest density was found in Metasequoia glyptostroboides forest, the smallest in Cinnamomum camphora forest. The largest groupe number was found in near-nature forest, the smallest was found in M. glyptostroboides forest. There was obvious seasonal dynamics in each urban forest type and green space which had larger density in autumn and larger groupe number in summer and autumn. In soil profiles, the degree of surface accumulation of soil meso- and micro-fauna in C. camphora forest was higher than in other forests and the vertical distribution of soil meso- and micro-fauna in near-nature forest was relatively homogeneous in four layers. Density-group index was ranked as: near-nature forest (6.953)> C. camphora forest (6.351)> Platanus forest (6.313)>M. glyptostroboides forest (5.910). The community diversity of soil fauna in each vegetation type could be displayed preferably by this index. It could be inferred through redundancy analysis (RDA) that the soil bulk density, organic matter and total nitrogen were the main environmental factors influencing soil meso- and micro-fauna community structure in urban forest. The positive correlations occurred between the individual number of Arcari, Enchytraeidae and soil organic matter and total nitrogen, as well as between the individual number of Diptera larvae, Rotatoria and soil water content.

[Characteristics of phytoplankton community changes in Dianshan Lake during peak period of algal blooms].

Based on the investigation data of phytoplankton in Dianshan Lake from May to October in 2009, the characteristics of phytoplankton community and the dominant species succession are studied. The results show that Cyanophyta and Chlorophta are the main taxa. Cyanophyta is dominant in cell abundance and Chlorophta is dominant in species variety. From the flat distribution, the species variety and density of Cyanophyta are higher in west and southwest. The peak of cell density reaches 23.40 x 10(7) cells x L(-1) in September due to the occurrence of cyanobacterial bloom, Cyanophyta account for 90.3 percents, with significant differences in each point (ANOVA, P < 0.05). An obvious succession of phytoplankton species is found, Microcystis of Cyanophyta become the dominant taxa and then conglutinated together to form water bloom. Temperature and pH are the main factors that affect the cyanobacterial bloom, and wind direction is an important reason for the horizontal distribution of the bloom-forming Microcystis. The phytoplankton diversity index is poor in central and western sites, diversity index decreases during cyanobacterial bloom and the community structures are simple.

[Niche analysis of phytoplankton's dominant species in Dianshan Lake of East China].

By using modified Levins and Petraitis formulae, this paper determined the niche breadth and niche overlap of the phytoplankton's dominant species in Dianshan Lake of East China, and analyzed the relationships between the niche breadth and niche overlap and the density and dominance of the dominant species. The niche breadth and niche overlap of the dominant species differed in different periods, and different dominant species had different adaptive capacity to the environmental factors. Based on their niche breadth in different seasons, the dominant species in the Lake could be classified into four groups, among which, Chroomonas acuta and Chlorella vulgaris had broader niche, more quantity, wider distribution, and better use of environmental resources. During cyanobacterial blooms, the niche overlap among Cyanophyta species was comparatively higher, Microcystis aeruginosa had broader niche breadth, but other species showed lower niche breadth. Correlation analysis showed that the dominance of the dominant species in different seasons had significant correlation with their niche breadth, and the dominant species density had significant correlation with their niche overlap.

[Phytoplankton productivity and its influencing factors in Dianshan Lake].

To understand the relationship between the spatial-temporal variations of phytoplankton primary productivity and its environmental factors in Dianshan Lake, monthly survey was carried out from April, 2009 to March, 2010, with the method of white and black bottles. The result shows that seasonal variation of primary productivity (calculated according to carbon, following the same) is summer [0.95 g x (m3 x d)(-1)] > winter [0.83 g x (m3 x d)(-1)] > spring [0.77 g x (m3 x d)(-1)] > autumn [0.62 g x (m3 x d)(-1). From the flat distribution, primary productivity is higher in northern and southern parts than that in east and west, with no significant differences in each point (p > 0.05). From the vertical distribution, phytoplankton light availability is an important limiting factor. Primary production of 0. 3 m underwater is higher than that of 0.5 m. However, primary production of 0.3 m level in summer is lower because of light inhibition. Seasonal changes in primary productivity may be due to phytoplankton community structure and replacement of the dominant species. There are significantly positive correlation between Chlorophyll a (Chl-a) and phytoplankton density with primary productivity (p < 0.01), and Chl-a has better correlation with primary productivity. Phytoplankton biomass shows a positive reaction to its productivity and may preliminary provide a reference for the number of phytoplankton.