Tropical forest soils serve as substantial and persistent methane sinks.

Although tropical forest soils contributed substantially global soil methane uptake, observations on soil methane fluxes in tropical forests are still sparse, especially in Southeast Asia, leading to large uncertainty in the estimation of global soil methane uptake. Here, we conducted two-year (from Sep, 2016 to Sep, 2018) measurements of soil methane fluxes in a lowland tropical forest site in Hainan island, China. At this tropical forest site, soils were substantial methane sink, and average annual soil methane uptake was estimated at 2.

[Physiological Effect of Vallisneria natans Under Different Concentrations of Nitrogen, Phosphorus and Chloramphenicol].

The effects of peroxidase(POD), superoxide dismutase(SOD) activities and malondialdehyde(MDA), soluble proteins and chlorophyll in the leaves of Vallisneria natans exposed to different concentrations of nitrogen and phosphorus in the eutrophication water body and chloramphenicol after 7 days were investigated in the study. The soluble protein content increased significantly in group eutrophic water and 0.2 µg.

[Acute Toxicity and Safety Assessment of Three Typical Organic Pollutants to Two Aquatic Organisms].

Acute toxic effects of three typical organic pollutants 1 ,2,4-trichlorobenzene (1,2,4-TCB), nitrobenzene and chlorpyrifos were investigated using Tetrahymena thermophila and Limnodrilus hoffmeisteri as living test organisms under laboratory conditions. The results showed that with the increase of pollutants' concentration and the extension of time, toxicity of the three kinds of pollutants significantly enhanced, and the mortality of two kinds of aquatic organisms also had a rising trend, and an obvious dose-effect relationship. The 96 h-LC50.

[Toxicity of three chlorophenols to protozoa Tetrahymena thermophila].

Using Tetrahymena thermophila as the indication organism, the single acute toxicity and genotoxicity induced by 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP) were determined. The results showed that the 24, 48, 72 and 96-hour EC50 values of 3 individual CPs to T. thermophila were 3.

[Acute toxicity of three typical pollutants to aquatic organisms and their water quality criteria].

Two species of microalgae Chlorella pyrenoidosa, Scenedesmus obliqnus and a red worm Chironomidae larvae were selected as test organisms in determining the acute toxicity effects of Cr (VI), 2,4,6-trichlorophenol and nitrobenzene. The results were able to provide more information on water quality criteria and more data on their toxicity to indigenous aquatic organisms in China. The 96 h-EC50 values of Cr (VI), TCP and nitrobenzene on C.

[Toxic effects of high concentrations of ammonia on Euglena gracilis].

Ammonia is among the common contaminants in aquatic environments. The present study aimed at evaluation of the toxicity of ammonia at high concentration by detecting its effects on the growth, pigment contents, antioxidant enzyme activities, and DNA damage (comet assay) of a unicellular microalga, Euglena gracilis. Ammonia restrained the growth of E.

Toxicological responses of earthworm (Eisenia fetida) exposed to metal-contaminated soils.

The aim of this study was to evaluate the toxicological responses of earthworm (Eisenia fetida) induced by field-contaminated, metal-polluted soils. Biochemical responses and DNA damage of earthworm exposed to two multi-metal-contaminated soils in a steel industry park and a natural reference soil in Zijin Mountain for 2, 7, 14, and 28 days were studied. Results showed that three enzyme activities, including superoxide dismutase (SOD), acetylcholinesterase (AChE), and cellulase, in earthworm in metal-contaminated soils were significantly different from those of the reference soil.

[Genotoxicity effect of organic pollutants in Meiliang Bay of Taihu Lake on microalga Euglena gracilis].

Organic pollutant ingredients and content of water samples from Taihu Lake were analyzed by GC-MS. Results showed that Taihu Lake was already contaminated by the organic pollutant, and 15 kinds of targeted organic pollutants were detected. At lower concentrations (1 time), organic pollutants could not have notable effect on the growth of Euglena gracilis, but could increase the content of photosynthetic pigment.