浙南近海虾类群落结构及其多样性分析

作者根据2015年11月(秋季)、2016年2月(冬季)、2016年5月(春季)和2016年8月(夏季)对浙南近海进行的渔业资源调查数据,用生物量作为虾类资源分布的数量指标,对该海域虾类的组成、数量分布以及季节变化进行分析。结果显示:该区域共鉴定出虾类30种,隶属于10科21属,以对虾科(Penaeidae)虾类最多,其次为管鞭虾科(Solenoceridae),长臂虾科(Palaemonida)位居第3位。按季节来看,秋季共鉴定虾类27种,各站位平均生物量为6.97 kg/km2,优势种为凹陷管鞭虾(Solenocera koelbeli)、中国毛虾(Acetes chinensis)和中华管鞭虾(Solenocera crassicornis)等3种;冬季鉴定出虾类25种,平均生物量为1.65 kg/km2,优势种为凹陷管鞭虾、扁足异对虾(Atypopenaeus stenodactylus)、日本鼓虾(Alpheus japonicus)、鲜明鼓虾(Alpheus digitalis)、中国毛虾、中华管鞭虾和周氏新对虾(Metapenaeus joyneri)等7种;春季20种,平均生物量为2.22 kg/km2,优势种为戴氏赤虾(Metapenaeopsis dalei)、东海红虾(Metapenaeopsis dalei)和中华管鞭虾等3种;夏季16种,平均生物量为10.36 kg/km2,优势种有鹰爪虾(Trachysalambria curvirostris)和中华管鞭虾等2种。Margalef丰富度指数(D)、Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J′)秋季均低于冬季。秋冬季受到浙闽沿岸流影响,温度、盐度相对较低,夏季受到台湾暖流外侧影响,温度、盐度相对较高,且各季节间由于瓯江、椒江、飞云江、鳌江等陆源性冲淡水的影响,盐度、温度变化相对较大,使得该区域的物种不得不适应一个跨度较大的温盐范围,广温广盐性种类为主。     

Boussinesq相位解析的海岸水动力学数学模型研究进展

由于在平衡计算效率和精度上具有优势,Boussinesq相位解析数学模型研究不断取得突破,已成为波浪和水流精细化模拟的较优解析方式,为海岸工程、环境、地质等问题提供了实用和高效的研究手段。本文对已有Boussinesq类模型的研究进行了评述,深入探讨其重要发展、实际应用和理论瓶颈,从高阶非静压修正、GPU准三维高性能算法编译、波浪破碎和泥沙运移沉积等4个方面提出未来可能的科学突破方向。     

基于GIS/RS的海岸带生态环境变化研究综述

近年来,随着沿海地区经济建设的脚步的不断加快,人们逐渐加大了对海岸带环境资源的开发利用。海岸带填海造陆、滩涂围垦等人类活动的增多使得区域生物及非生物物质发生了剧烈的改变,进而对海岸带生态环境产生了重要的影响。基于此,各国学者尝试通过一系列的技术手段与方法模型对海岸带生态环境时空变化进行相关探究。其中,遥感与地理信息系统技术作为生态环境的重要分析工具,在区域生态环境变化的评估与监测中有着较为广泛的应用。在海岸带生态环境变化的探究中,由于研究目的、角度以及方向的不同,相关学者所使用的研究方法及模型也存在着一定的差别。本文结合海岸带生态环境研究现状,将海岸带生态环境变化研究分成海岸带土地利用/覆被变化研究、景观格局变化研究、海岸线变迁变迁研究、植被变化研究、水土环境表征因子变化研究以及基于指标体系的生态环境变化研究6个主要部分,并分别从这6个部分出发,对海岸带生态环境变化研究的技术、方法与模型进行归纳总结,从而提出未来我国海岸带生态环境变化研究中需要解决的问题以及重点研究方向,为今后海岸带生态环境的深入研究打下坚实的基础。     

不同排列方式和间隙比下双圆柱流致振动特性研究

采用基于ALE的流固耦合分析方法,将圆柱体振动模型简化为平面双自由度质量-弹簧-阻尼系统,进行了计算参数无关性分析。对不同θ角和间隙比T下的双圆柱流致振动进行数值模拟,并与单圆柱振动计算结果进行比较,得到了不同θ角和间隙比T下中心圆柱的升阻力系数、流场分布和运动轨迹变化情况。通过分析发现小间隙比下由于两圆柱间的相互干扰,改变了中心圆柱的尾涡结构,导致了升力和阻力系数随不同θ角而发生变化;小间隙比下由于两圆柱间的相互干扰影响,均使中心圆柱的轨迹在不同θ角下发生了较大的变化,顺流向的振动频率与单圆柱振动时相比出现了多倍频,导致其运动轨迹发生了变化。     

基于VSD模型的铁山港湾红树林生态系统脆弱性初步评价

基于脆弱性域图 (vulnerability scoping diagram, VSD)评价模型, 从暴露程度、敏感性、适应能力3个方面构建了红树林生态系统脆弱性评价指标体系。采用改进的综合指数法和模糊综合评价法, 重新定义脆弱性分级标准, 定量评价了铁山港湾红树林生态系统在1989年、2003年和2014年3个年份的脆弱性水平。结果显示, 铁山港湾红树林生态系统在3个年份的脆弱性水平值分别为0.145、0.255、0.334, 呈现增加趋势。首先, 铁山港湾红树林生态系统面临的暴露程度不断增大, 主要胁迫因子为滩涂围垦面积、废水排放量; 其次, 生态系统的敏感性增强, 主要敏感因子是海洋生物质量综合指数、底栖生物和潮间带生物多样性指数; 第三, 生态系统的适应能力略有增加, 总体上较弱。     

Soil Organic Carbon Contents and Stocks in Coastal Salt Marshes with Spartina alterniflora Following an Invasion Chronosequence in the Yellow River Delta,China

Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m~2) were significantly increased(P 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R~2 = 0.43, P 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.     

Changes of Biogenic Elements in Phragmites australis and Suaeda salsa from Salt Marshes in Yellow River Delta,China

Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.     

The Characteristic Patterns of Macrofaunal Fouling Assemblages in Nearshore Waters of the South China Sea

The spatio-temporal patterns of macrofaunal fouling assemblages were quantitatively investigated in the nearshore waters of the South China Sea. The work was undertaken by deploying seasonal panels at two sites (H-site, L-site) for one year, and the fouling communities on the panels were examined and analyzed. The results indicated that species composition of assemblages was obviously different between the two sites. At both sites the assemblages were characteristic with solitary dominant species throughout the year, with Amphibalanus reticulates dominating at H-site and Hydroides elegans at L-site. Shannon index and biomass of the assemblages varied with depth and season at both sites. At H-site the total biomass in summer and autumn were significantly higher than those in spring and winter, while at L-site the assemblage biomass also differed significantly among the four seasons, and the greatest biomass occurred at the depth of 2.0 m in winter. The abundance of all seasonal samples in non-metric multidimensional scaling was clustered as one group at L-site and three groups at H-site. The environmental factors were more likely to be related to the variation of fouling assemblages. Furthermore, it also suggests that in tropical seas the integrated adaptability would qualify a species for dominating a fouling assemblage despite its short life cycle, rather than the usually assumed only species with long life span. This study reveals the complexity and characteristic dynamics of macrofaunal fouling assemblages in the tropical habitats, and the results would provide valuable knowledge for biodiversity and antifouling research.     

The Influence of Two Kinds of El Niño Events on the Strong Tropical Cyclone Generation and Strength in the Pacific Ocean

This paper focuses on the effects of two types of El Niño events on tropical cyclone activity. We classified El Niño events from 1961 to 2015 according to their sea surface temperature (SST) anomalies into an eastern type and a central type. Then we selected strong tropical cyclones to statistically analyze the tropical cyclone characteristics during different events and their effects, as well as to study the possible mechanisms related to thermodynamic and dynamic factors. The tropical cyclone generation areas were found to be very similar during the two kinds of events. The average number of tropical cyclone in the eastern event is more than that in central event, and the hurricane in northeastern Pacific (HNP) has more energy than the typhoon in northwestern Pacific (TNP) in all cases. The seasonal distribution of the TNP high-incidence centers during central El Niño events is opposite to that of the HNP. The TNP accumulated cyclone energy (ACE) intensity is similar in the fall and summer, and the HNP ACE intensity in the summer is greater than that in the fall. The SSTs are consistent with the TNP and HNP movement trends. The Walker circulation intensity was strongly affected by the eastern events, but it quickly returned to its normal state, while the intensity was slightly reduced in the central events, and it slowly returned to its normal state. The vertical velocity distributions in the Pacific are different at different stages of both events, and the distributions of vertical velocity anomalies for typhoons and hurricanes are consistent.