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Phragmites australis, a perennial herb and a widespread species, is widely distributed in coastal wetland in the Yellow River Delta. Laboratory experiments were carried out to assess the effects of water and salinity on seed germination of P. australis and recovery response after seed transferred to distilled water. The germination responses of seeds were determined over a wide range of salinities of 0, 0.5, 1, 2, 2.5, and 3% and water depths of 0, 2, 4, 6, 8, 10, and 15 cm. Final percent germination and germination speed except for at 0.5% salinity treatment were decreased with increasing salinities. Lower salinity (0.5%) could stimulate germination of P. australis, while seed germination was nearly inhibited completely at salinity 3%. P. australis percent germination was decreased with water depth increasing except 2 cm water depth treatment. Percent germination and speed were great and fast at lower water depth. After end of the recovery period, the final percent germination of P. australis after high salinity treatments (2, 2.5, and 3%) was up to 80%, while those after low salinity treatments were lower than 1%, and percent germination after different water depth treatments was zero. The results indicate that it is possible to accelerate the degraded coastal wetland restoration process of P. australis population by sexual ways in the Yellow River Delta. [ABSTRACT FROM AUTHOR]

The composition and stability of soil aggregates are important indicators for measuring soil quality, which would be affected by land use changes. Taking wetlands with different returning years (2 and 15 years) in the Yellow River Delta as the research object, paddy fields and natural wetlands as control, we analyzed the changes in soil physicochemical properties and soil aggregate composition. The results showed that soil water content, total organic carbon, dissolved organic carbon and total phosphorus of the returning soil (0-40 cm) showed an overall increasing trend with returning period, while soil pH and bulk density was in adverse. There was no significant change in clay content, electrical conductivity, and total nitrogen content. The contents of macro-aggregates and micro-aggregates showed overall increasing and decreasing trend with returning period, respectively. The stability of aggregates in the topsoil (0-10 cm) increased with returning years. Geometric mean diameter and mean weight diameter increased by 8.9% and 40.4% in the 15 th year of returning, respectively, while the mass proportion of >2.5 mm fraction decreased by 10.5%. There was no effect of returning on aggregates in subsoil (10-40 cm). Our results indicated that returning paddy field to wetland in the Yellow River Delta would play a positive role in improving soil structure and aggregate stability.

The temperature sensitivity of soil carbon mineralization ( Q 10 ) is an important index to evaluate the responses of ecosystem carbon cycling to climate change. We examined the effects of three electron acceptors [SO 4 2- , NO 3 - and Fe(Ⅲ)] addition on the Q 10 value of anaerobic carbon mineralization of Phragmites australis community soil (0-10 cm) in the Yellow River Estuary wetland with the closed culture-gas chromatography method. The results showed that the three electron acceptors addition inhibited the production of CO 2 and CH 4 during the 48-day culture period, with a decrease of 17.3%-20.8% for CO 2 and 29.2%-36.2% for CH 4 . Generally, the CO 2 production differed with the concentrations of electron acceptors, while CH 4 production differed with the type of electron acceptors. The CO 2 :CH 4 ratios were significantly different with temperature, indicating an obvious temperature dependence for the anaerobic carbon mineralization pathway. The Q 10 values of CO 2 and CH 4 production under three electron acceptor additions ranged from 1.08 to 1.11 and from 1.19 to 1.37, respectively, showing an increasing trend compared with the control. The type and concentration of electron acceptors affected the temperature dependence of CO 2 production, while electron acceptors affected that of CH 4 production. It is suggested that the input of reducing salts would retard the mineralization loss of organic carbon in estuary freshwater wetlands under the background of climate change, but enhance the sensitivity of carbon mineralization to increasing temperature.

The Quaternary sediment in the Ningbo Coastal Plain was the deposit due to sea-land interaction, which recorded information of past climate changes. The region is therefore an ideal area to study paleoclimate changes and sedimentary characteristics. We determined the stratigraphic division and paleoenvironmental evolution based on 14 C and paleomagnetic dating, along with detailed analyses of lithology, pollen assemblage, foraminifera and ostracodes assemblage, and grain size of sediment in core Z02 located in the southeastern Ningbo Coastal Plain. The results showed that the boundary between the Holocene and Upper Pleistocene in the core Z02 record was at 30.5 m, the boundary between the Upper and Middle Pleistocene was at 82.65 m, and the boundary between the Quaternary and Lower Cretaceous was at 90 m. The Middle Pleistocene section of the core contained few sediments, while the Lower Pleistocene section was completely missed. During the late Pleistocene, the hydrodynamic conditions experienced energy levels of medium to medium low to medium, and sedimentary facies changed from alluvial lake to overbank to river to lake to alluvial lake to lake to overbank. During the Holocene, the hydrodynamic changes experienced energy levels of medium low to low to medium, and the sedimentary facies changed from shoreland to shallow sea to shoreland lake. The Ningbo Coastal Plain had experienced tectonic uplift, weathering and erosion stage in the Early and Middle Pleistocene, from warm and humid to dry in the Late Pleistocene, and from warm and humid to dry and cool in the Holocene, as revealed by the core Z02 record. This study provided useful information in investigating past environmental changes in the subtropical coastal region of eastern China.

The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of β T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0-20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing β-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion.

The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO4 (2-) and Na(+) were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m(-2), in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3 (-)-N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4 (+)-N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3 (-)-N and NH4 (+)-N was ~31.38% and ~20.50% for the contents of NO3 (-)-N and NH4 (+)-N in 0-10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

Zinc one of the key elements that influence human genetic health, was selectively determined in this paper. In the area of metal elements determination in body fluid, most samples used in the study are blood, plasma and saliva. No literature about genetic fluid determination has been found so far. In this paper the preparation of samples, volume of samples and determination parameters were investigated. An easy reliable method of determining zinc in semen and liquor folliculi was established. The recoveries are 92.0%-107.6%, the detection limit is 0.002 mg x L(-1) and the relative standard deviations (RSD) (n = 5) are 1.3%-10.0%.