Evapotranspiration dynamics and their drivers in a temperate mixed forest in northeast China.

Evapotranspiration (ET) is a vital part of the global water cycle and is closely related to carbon sequestration. Analysing ET dynamics and their drivers would benefit for improving our understanding of the global water and carbon cycles. Using an eddy covariance (EC) approach, we analysed ET dynamics and their drivers in a temperate mixed forest over northeast China from 2016 to 2017. The results showed that 43.55% of our eddy covariance data passed the quality control. In addition, the energy balance ratio was 0.62, indicating that measurements were reliable. The measured ET showed clear single peak patterns with seasonal and diurnal variations. The daily ET ranged from 0 to 7.75 mm d-1 and the hourly ET ranged from 0 to 0.28 mm h-1. The ranges of hourly ET floated from 0 to 0.05 mm h-1 at non-growing season (November to April) while ranged from 0 to 0.28 mm h-1 at active growing season (May to October). The diurnal ET dynamics during the non-growing season were driven by air temperature (T a), but were governed by global radiation (R g) during the active growing season. Leaf area index (LAI) comprehensively reflected the variations of T a and R g, and was found to be the primary factor shaping the seasonal dynamics of ET. The annual ET rates were 501.91 ± 5.30 mm year-1 and 554.60 ± 11.24 mm year-1 for 2016 and 2017, respectively. Therefore, energy supply, represented by T a and R g, governed ET dynamics in our temperate mixed forest, while variables representing the energy supply affecting ET dynamics differed among seasons and time scales. ET dynamics indicated that a temperate mixed forest is important to the global water cycle. Our results improved our understanding of ET dynamics in the studied region.

[Clinical efficacies of scleral tunnel sutureless trabeculectomy plus phacoemulsification and intraocular lens implantation].

OBJECTIVE: To explore the clinical efficacies of scleral tunnel sutureless trabeculectomy plus phacoemulsification and intraocular lens implantation in the treatment of glaucoma and cataract. METHODS: A total of 49 cataract patients with glaucoma (52 eyes) from our hospital during the period of February 2009 to June 2012. Their visual acuities were < 0.3 and intraocular pressure was not desirable or in need of various ocular hypotensive drugs. A phaco tunnel knife was employed to prepare a 4 mm × 4 mm scleral tunnel flap with 1/2-2/3 whole layer of sclera depth. Phacoemulsification instrument was used to emulsify cataracts. Foldable intraocular lens was implanted. A trabecular cut of 2 mm × 1.5 mm was made under the scleral tunnel. Tile scleral flap was not sutured and conjunctival flap tightly closed. RESULTS: After a 12-month follow-up, > 0.5 in 42 eyes (80.8%). The intraocular pressure was 11.32 - 17.63 mm Hg (1 mm Hg = 0.133 kPa) and the mean intraocular pressure (13.59 ± 4.26) mm Hg. There was a mean pressure reduction of 11.2 mm Hg from (24.53 ± 5.71) mm Hg pre-operation. Statistical significance existed (t' = 11.073, P < 0.01). The filtering blebs of type I-II was 43 eyes (82.6%) and the mean central anterior chamber 3.28 mm ± 0.42 mm. There was statistical difference (t' = 20.486, P < 0.01) with (1.79 ± 0.31) mm at pre-operation. On 52 eyes, the mean postoperative astigmatism was (1.01 ± 0.62) D versus (1.13 ± 0.74) D at pre-operation. There was no statistical significance (F = 2.0673, P > 0.05). No severe complication occurred in all cases. CONCLUSION: Compared with traditional trabeculectomy and triple procedure, this improved and updated procedure lowers intraocular pressure, improves visual acuity and decreases the occurrences of complications. It is a safe, reasonable, quick and effective treatment for cataract patients with glaucoma.

[Vertical distribution of soil organic carbon and total nitrogen in reed wetland].

With element analyzer, this paper measured the variation of organic carbon and total nitrogen in different soil depths of reed wetland. The results showed that soil organic carbon, total nitrogen, and C/N ratio were decreased gradually with increasing soil depth, and their accumulation peaks were differed with soil layers and months. Soil temperature and moisture and the growth status of reed were the main factors caused the differences. Soil organic carbon was strongly positively correlated with soil total nitrogen content in July, August and October, the R2 being 0.73, 0.73 and 0.71 respectively, but weakly correlated in September. Soil C/N ratio was negatively correlated to soil organic carbon and total nitrogen, but the correlativity was higher with soil total nitrogen than with soil organic carbon, suggesting that soil C/N ratio was more determined by the content of soil total nitrogen.