Nutrient exchanges at the sediment-water interface and the responses to environmental changes in the Yellow Sea and East China Sea.

Release from the sediment is an important nutrient source to the water column of global oceans, especially for marginal seas with active biogeochemical processes. Benthic nutrient biogeochemistry and its responses to environmental changes were investigated in the eastern marginal seas of China using a two-layer diffusion-advection-reaction diagenetic model. Overall, the sediment represented the primary nutrient source with fluxes of ~-342 ± 197, -1.25 ± 0.50, and -114 ± 56 × 108 mol/month for dissolved inorganic nitrogen (DIN), phosphate, and silicate, respectively. This could contribute up to ~42% of nutrients requested by primary production (PP), with a DIN/SiO32-/PO43- molar ratio of 273:91:1, which was higher than that in the overlying water (49:47:1). Future benthic nutrient fluxes were predicted under two environmental change scenarios (increasing and decreasing PP and biogenic silica). Our study may help rebuild nutrient budgets in the future and formulate environmental management policies in marginal seas.

Factors associated with decreased bone mineral density in postmenopausal women with schizophrenia.

OBJECTIVE: This study examined the risk factors for decreased bone mineral density (BMD) in postmenopausal women with schizophrenia. METHODS: Cluster sampling method was adopted in this large-sample, cross-sectional study. A total of 219 postmenopausal female inpatients with schizophrenia were selected and interviewed in Beijing. The average age of the patients was 60.4±7.0 years. Clinical assessment instruments included the Positive and Negative Syndrome Scale (PANSS) and a questionnaire with detailed general information and disease-related investigations. Laboratory measurements included prolactin (PRL), estradiol, progesterone, thyroid stimulating hormone, FT3, and FT4. BMD testing was performed by dual-energy X-ray absorptiometry. RESULTS: The prevalence of osteoporosis or osteopenia was 66.2% (n=145). Decreased BMD was associated with age, illness duration, therapeutic dose (equivalent chlorpromazine dose), treatment duration, PANSS-negative scores, body mass index (BMI), daily exercises (min/d), drinking (unit/wk), PRL, and estradiol. Multiple logistic regression analysis revealed that age, treatment duration, PANSS-negative score, BMI, and PRL were significantly associated with decreased BMD. CONCLUSION: Prevalence of BMD loss was higher in Chinese postmenopausal women with schizophrenia compared to the normal BMD group. A combination of demographic and clinical factors play important roles in determining decreased BMD, including older age, longer treatment duration, more PANSS-negative scores, higher BMI, and higher PRL level.

[Study on distribution of phosphorus in surface sediments of the Yellow Sea and the East China Sea].

Different phosphorus compositions (TP, IP and OP) were determined in surface sediments of the Yellow Sea (YS) and the East China Sea (ECS),sampled from two cruises between March and June, 2011. The results showed that, contents of TP were from 10.50 micromol x g(-1) to 24.10 micromol x g(-1), IP ranged from 7.14 micromol x g(-1) to 17.10 micromol x g(-1) was the major phosphorus speciation accounting for more than 70% in TP. The percent of IP in TP at most stations was between 50% and 90% , only four stations which lied in the East China Sea with the percent was over 90%. The dominant factors affecting the phosphorus concentration and distribution in surface sediments were anthropogenic activities, sources of input materials, grain size, depositional environments and hydrological conditions. TP burial flux (TPBF) that appeared regional differences was affected by sedimentation rates, porosity and oxygen in bottom water, but TP content and sedimentation rates were crucial factors for TPBF.

[Distribution and air-sea fluxes of methane in the Yellow Sea and the East China Sea in the spring].

A survey was carried out in the Yellow Sea and the East China Sea from March 17 to April 06 of 2011. Dissolved CH4 in various depths were measured and sea-to-air fluxes were estimated. Methane concentrations in surface and bottom waters ranged between 2.39-29.67 nmol x L(-1) and 2.63-30.63 nmol x L(-1), respectively. Methane concentrations in bottom waters were slightly higher than those in surface waters, suggesting the existence of methane source in bottom waters or sediments. The horizontal distribution of dissolved CH4 showed a decrease from the river mouth to the open sea, and was influenced by the freshwater discharge and the Kuroshio intrusion. Surface methane saturations ranged from 93%-1 038%. Sea to air CH4 fluxes were (2.85 +/- 5.11) micromol x (m2 x d)(-1) (5.18 +/- 9.99) micromol x (m2 x d)(-1) respectively, calculated using the Liss and Merlivat (LM86), the Wanninkhof (W92) relationships and in situ wind speeds, and estimated emission rates of methane from the East China Sea and the Yellow Sea range from 7.05 x 10(-2) - 12.0 x 10(-2) Tg x a(-1) and 1.17 x 10(-2) - 2.20 x 10(-2) Tg x a(-1), respectively. The Yellow Sea and East China Sea are the net sources of atmospheric methane in the spring.

[Distributions and pollution status of heavy metals in the suspended particles of the estuaries and coastal area of eastern Hainan].

The distributions and pollution status of heavy metals in the suspended particles were investigated in the Wanquan and Wenchang/Wenjiao estuaries and the coastal area of eastern Hainan in July 2008. The concentrations of metal elements (Al, Fe, Mn, Cr, Cu, Ni, V, Zn) were determined by ICP-AES after microwave digestion. Multivariate statistical methods (e. g. correlation analysis and principal factor analysis) were used to discuss the major factors controlling the variability of heavy metal concentrations and the pollution status in those areas. There was an obvious variability in particulate metal concentrations from upstream to estuary of both rivers. The concentrations first increased with increasing salinity and then decreased with further increase of the salinity; the concentrations were slightly higher at the coastal area in the east. The variability of particulate metal concentrations reduced significantly after the normalization by Al, indicating the effects of grain size. Enrichment factor calculation results showed that there was heavy metal pollution (especially Cu, Ni) in the Wenchang/Wenjiao River and estuary, while the situation in Wanquan River remained at pristine level. Concentrations of particulate metals in the study area were mainly controlled by source geology and provenance, as well as contamination from the discharge of waste water and biological activity.