Does the Port 2000 harbour construction have an effect on the Seine estuary suprabenthic community?

Using a Before/During/After protocol, the effects of Port 2000 (the Le Havre harbour extension) on the suprabenthic communities in the Northern Channel of the Seine estuary (English Channel) were examined from March 2001 to March 2009. Since the beginning of Port 2000 construction in 2002, there have been several changes in the hydrological and sedimentary characteristics in the North Channel, including changes in current velocity, bottoms salinity and sand accumulation, as well as in the benthic communities themselves, moving from mud to medium and coarse sand communities. For the suprabenthos, changes were moderate, corresponding to an increase in species richness in the upper-part of the North Channel and a decrease in species density in the dominant mysids species (i.e., mainly Mesopodospsis slabberi) over time. Due to hydrological changes since the beginning of the Port 2000 project (several years of low freshwater input) it has been difficult to attribute the biological changes to Port 2000 construction only. In the future, the results obtained for the suprabenthos will have to be compared to those obtained for the macrobenthos. Similarly, since the suprabenthos is known to play an important role in the estuarine trophic chain, it will also be essential to estimate the fish distribution in the North Channel and to examine their stomach contents to evaluate the probable changes since the Port 2000 project began.     

Sedimentary organic matter distributions,burrowing activity,and biogeochemical cycling: Natural patterns and experimental artifacts

The coupling between biogenic reworking activity and reactive organic matter patterns within deposits is poorly understood and often ignored. In this study, we examined how common experimental treatments of sediment affect the burrowing behavior of the polychaete Nephtys incisa and how these effects may interact with reactive organic matter distributions to alter diagenetic transport – reaction balances. Sediment and animals were recovered from a subtidal site in central Long Island Sound, USA. The upper 15 cm of the sediment was sectioned into sub-intervals, and each interval separately sieved and homogenized. Three initial distributions of sediment and organic substrate reactivity were setup in a series of microcosms: (1) a reconstituted natural pattern with surface-derived sediment overlying sediment obtained from progressively deeper material to a depth of 15 cm (Natural); (2) a 15 cm thick sediment layer composed only of surface-derived sediment (Rich); and (3) a 15 cm thick layer composed of uniformally mixed sediment from the original 15 cm sediment profile (Averaged). The two last treatments are comparable to that used in microcosms in many previous studies of bioturbation and interspecific functional interaction experiments. Sediment grain size distributions were 97.5% silt-clay and showed no depth dependent patterns. Sediment porosity gradients were slightly altered by the treatments. Nepthys were reintroduced and aquariums were X-rayed regularly over 5 months to visualize and quantify spatial and temporal dynamics of burrows. The burrowing behaviour of adult populations having similar total biovolume, biomass, abundance, and individual sizes differed substantially as a function of treatment. Burrows in sediment with natural property gradients were much shallower and less dense than those in microcosms with altered gradients. The burrow volume/biovolume ratio was also lower in the substrate with natural organic reactivity gradients. Variation in food resources or in sediment mechanical properties associated with treatments, the latter in part coupled to remineralization processes such as exopolymer production, may explain the burrowing responses. In addition to demonstrating how species may respond to physical sedimentation events (substrate homogenization) and patterns of reactive organic matter redistribution, these experiments suggest that infaunal species interactions in microcosms, including the absolute and relative fluxes of remineralized solutes, may be subject to artifacts depending on exactly how sediments are introduced experimentally. Nonlocal transport and cylinder microenvironment transport – reaction models readily demonstrate how the multiple interactions between burrowing patterns and remineralization rate distributions can alter relative flux balances, decomposition pathways, and time to steady state.     

新时代国土空间规划中陆海统筹的重点内容和实现路径

新时代国土空间规划是未来可持续发展的空间蓝图。陆地与海洋作为国土空间的两大主体,落实陆海统筹战略、推进生态保护和高质量发展已成为沿海地区国土空间规划编制的重要内容。文章阐述陆海统筹的重点内容并分析其实现路径,研究结果有助于推动陆海统筹在国土空间规划中的有效落实,提升国土空间规划编制的科学性。研究结果表明在新时代背景下,可从6个方面实现陆海统筹:有机衔接陆海主体功能,统筹协调岸线两侧矛盾,统筹塑造陆海空间格局;统筹规划陆海自然资源的保护与开发;统筹布局和协调发展陆海产业;建立陆海一体的交通和防灾支撑体系;开展陆海协同的生态环境保护与修复治理;建设陆海统筹的管理体制机制。     

柴达木盆地第三系咸水湖相生油岩古沉积环境地球化学特征

在系统分析柴达木盆地西部第三系咸水湖相生油岩样品的微量元素、有机物、粘土矿物组成的基础上,揭示了研究区生油岩的无机元素和有机质组成特征;并结合沉积环境的无机与有机地球化学指标,重建了生油岩沉积时的古沉积环境。生油岩的B、Cl-及伽玛蜡烷含量表明,沉积时的水介质条件是半咸水—咸水环境,并伴随湖盆沉积中心北迁过程各层位地层的盐度发生规律性时空]化;生油岩的Fe2 /Fe3 、S2-、Pr/Ph比值、藿烷碳数分布模式及黄铁矿含量反映其沉积时的沉积环境为强还原性;粘土矿物组合特征及含量揭示这些生油岩的沉积相带介于中心咸湖相和边缘咸湖相之间。     

Invertebrate recolonisation of previously dry channels in the Rakaia River

Recolonisation of previously dry channels by stream invertebrates was studied in the Rakaia River during winter 1981 and summer 1982. The winter experiment continued for 42 days, with stable low flows, whereas the summer experiment was characterised by fluctuating large flows which caused it to be abandoned after 27 days. The fauna was dominated numerically by Chironomidae, a leptophlebiid mayfly (Deleatidium), and oligochaetes during the winter, and by Deleatidium alone during the summer. Recolonisation was considered complete after 33 days in winter and 15 days in summer. Flow fluctuations were the main factor affecting colonisation rates, and it was assumed that drift was the main source of colonising animals. Small freshes during low‐flow periods in winter resulted in a rapid increase in total density of invertebrates and number of taxa present and also affected the population structure of Deleatidium larvae in colonisation baskets. Before these freshes numbers had increased steadily over a 27 day period. In summer large floods during high flow periods initially decreased benthic invertebrate numbers in samples but numbers increased rapidly once the flood had passed. This appears to be the first study of its kind on a large unstable river system.     

虹鳟(Oncorhynchus mykiss)选育群体的血清类固醇激素周年变化

采用放射性免疫(RIA)和组织学切片技术,系统地研究了虹鳟(Oncorhynchus mykiss)选育群体的血清性类固醇激素周年变化与性腺发育特点的关系,以及血清中性类固醇激素雌二醇(E2)和睾酮(T)在雌雄亲本中的周年变化规律和生理作用。结果表明,虹鳟性腺发育可划分为6期。雌鱼血清中E2在10月(V期性腺)达到峰值,T浓度在11月达到峰值,而进入繁殖期后(11—12月)E2开始下降。雄鱼血清T浓度在11月达到最大值,E2在6月份达到峰值,在11月之后T开始下降。在各月份,雌鱼E2浓度水平远高于雄鱼,而雄鱼T浓度个别月份低于雌鱼。这些研究揭示出,测定血清性类固醇激素浓度水平可用于准确判断鱼类的生殖状态,且可为虹鳟家系选育出早熟亲本群体提供重要技术依据。     

Statistical analysis and forecasts of long-term sandbank evolution at Great Yarmouth, UK

A data-driven model has been developed to analyse the long-term evolution of a sandbank system and to make ensemble predictions in a period of 8 years. The method uses a combination of empirical orthogonal function (EOF) analysis, (to define spatial and temporal patterns of variability), jack-knife resampling, (to generate an ensemble of EOFs), a causal auto-regression technique, (to extrapolate the temporal eigenfunctions), and straightforward statistical analysis of the resulting ensemble of predictions to determine a ‘forecast’ and associated uncertainty. The methodology has been applied to a very demanding site which includes a curved shoreline and a group of mobile nearshore sandbanks. The site is on the eastern coast of the UK and includes the Great Yarmouth sandbanks and neighbouring shoreline. A sequence of 33 high quality historical survey charts reaching back to 1848 have been used to analyse the patterns and to predict morphological evolution of the sandbank system. The forecasts demonstrate an improved skill relative to an assumption of persistence, but suffer in locations where there are propagating features in the morphology that are not well-described by EOFs.     

涠洲岛潮滩表层沉积物中重金属的空间分布及其环境质量评价

根据2006年4月对涠洲岛潮滩表层沉积物的调查资料,分析了表层沉积物中重金属元素Hg、Cu、Pb、Zn、Cd、Cr、As的含量水平及空间分布特征,运用单因子评价法对其环境质量进行了评估,并通过相关性分析、因子分析探讨了几种重金属元素的物源.结果表明:涠洲岛潮滩环境质量状况良好,各元素均未达到污染水平,多数地区存在Cu的玷污,个别地区存在As的玷污;各分析元素较多的累积在人为活动相对频繁的XKZ、W05断面附近区域;Hg、Cu、Zn、Cr显著正相关,以环境背景来源为主,Pb、As较多的受到人为因素的影响.     

锦州9-3油田海域环境现状及其评价

1 引言 石油,作为现代社会的主要能源,在全球经济迅速发展和人口激增的情况下,世界范围内的供求在不断增长,海洋石油勘探开发规模也在不断扩大.海洋油气开发已成为我国油气战略资源的主要来源之一.     

Benthic nitrate biogeochemistry affected by tidal modulation of Submarine Groundwater Discharge (SGD) through a sandy beach face, Ria Formosa, Southwestern Iberia

To investigate both the role of tides on the timing and magnitude of Submarine Groundwater Discharge (SGD), and the effect on benthic nitrogen biogeochemistry of nitrate-enriched brackish water percolating upwards at the seepage face, we conducted a study of SGD rates measured simultaneously with seepage meters and mini-piezometers, combined with sets (n = 39) of high resolution in-situ porewater profiles describing NH₄⁺, NO₃⁻, Si(OH)₄ and salinity distribution with depth (0–20 cm). Sampling took place during two consecutive spring tidal cycles in four different months (November 2005, March, April and August 2006) at a backbarrier beach face in the Ria Formosa lagoon, southern Portugal. Our results show that the tide is one of the major agents controlling the timing and magnitude of SGD into the Ria Formosa. Intermittent pumping of brackish, nitrate-bearing water at the beach face through surface sediments changed both the magnitudes and depth distributions of porewater NH₄⁺ and NO₃⁻ concentrations. The most significant changes in nitrate and ammonium concentrations were observed in near-surface sediment horizons coinciding with increased fraction of N in benthic organic matter, as shown by the organic C:N ratio. On the basis of mass balance calculations executed on available benthic profiles, providing ratios of net Ammonium Production Rate (APR) to Nitrate Reduction Rate (NRR), coupled to stoichiometric calculations based on the composition of organic matter, potential pathways of nitrogen transformation were speculated upon. Although the seepage face occasionally contributes to reduce the groundwater-borne DIN loading of the lagoon, mass balance analysis suggests that a relatively high proportion of the SGD-borne nitrogen flowing into the lagoon may be enhanced by nitrification at the shallow (1–3 cm) subsurface and modulated by dissimilatory nitrate reduction to ammonium (DNRA).