Analysis of Jiangsu Tidal Flats Reclamation from 1974 to 2012 Using Remote Sensing

Jiangsu has the most abundant tidal flat resources among China’s coastal provinces. To ease the conflict between the growing population and shrinking usable land and to promote regional sustainable development, large-scale coastal reclamation development activities have been performed in Jiangsu Province since 1949. The present study has integrated multi-source remote sensing images during 1974 to 2012 by using a Multi-point Fast Marching Method (MFMM) to extract the Jiangsu coastal reclamation areas for different time periods. The temporal and spatial patterns of the extent and elevation of the reclamation areas were analysed in order to determine the unused potential for future reclamation. It will provide information necessary to support the development and construction of tidal flats in Jiangsu. Results show that: (1) the reclaimed tidal flats along the Jiangsu coast cover more than 19.86×104 hm2, of which 13.97×104 hm2 is located in Yancheng, 4.84×104 hm2 in Nantong, and 1.05×104 hm2 in Lianyungang; (2) the average elevation of the reclaimed Jiangsu tidal flats has gradually decreased over the last 40 years, while those in Dongtai and Rudong have showed particularly accelerated decrease since the 1990s; and (3) in 2012, very few unused tidal flats two meters above the sea level are left along the Jiangsu coast, and mainly concentrated in Yancheng. As there are still reserving some coastal land resources between 0?2 m, providing us with a potential for future development. All of these findings may be useful for researchers and local authorities for the development and utilization of tidal flat resources in Jiangsu.     

肥城煤田太原组沉积特征与聚煤规律

根据肥城煤田石炭系太原组的岩性、粒度分布、沉积构造、地球化学及古生物等沉积特征,将该区晚石炭世古地理划分为碳酸盐开阔台地和潮坪环境,认为太原组形成于潮汐作用为主的陆表海海岸,泥炭坪是成煤的重要古地理环境,潮渠对煤层有一定的破坏作用,地壳的脉动性振荡作用是控制沉积环境演化和聚煤作用的主要因素。      

青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis (Asano,1951)壳体δ18O值的季节变化

近岸浅水底栖有孔虫是陆架海区古环境重建的重要手段,但是至今对其活体的研究非常缺乏。2014年6月至2015年5月对青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis进行了连续12个月的采样,用虎红染色以确认活体。对壳径范围在200~550μm的活体壳体,以每增加50μm壳径为一组,进行δ18O测试。结果显示,A.aomoriensis壳体δ18O的月平均值的季节变化趋势与温度和盐度一致,与温度反相关,与盐度正相关,即青岛湾A.aomoriensis壳体δ18O值受温度和海水δ18O的影响,其壳体δ18O值表现出了很好的季节性波动。但是A.aomoriensis壳体δ18O的变化滞后于所测温度和盐度约2个月,其记录的是虫体在生长周期内在真实钙化温度下分馏所得的δ18O值。     

Molluscan Hard-Substrate Associations in the Northern Red Sea

Abstract. The mollusc associations of 29 hard-substrate localities in the Northern Bay of Safaga Red Sea, Egypt were studied. The hard substrates were classified into 7 types: reef flats, intertidal rock bottom, very shallow subtidal conglomerate, Porites carpet, faviid carpet, platy scleractinian association, Sarcophyton carpet. Based on a cluster analysis the molluscs of these hard substrates can be classified into 5 groups: Group A is dominated by Dendropoma maxima , Chamoidea and Tridacna maxima , group B by Pedum spondyloideum, T. maxima and Coralliophila neritoidea , group C by Chamoidea and Cerithium rüppelli , group D by Modiolus auriculatus , Chamoidea, Morula granulata and Nerita albicilla and group E by Chamoidea and Pitar hebraea . The latter group contains only samples which are generally poor in molluscs. Group A molluscs are diagnostic for reef flats, group B for Porites and faviid carpets, group C for Sarcophyton carpets and group D for tidal/shallow subtidal rock substrates. The different hard substrates are therefore characterized by diagnostic mollusc associations and some of them could also be identified in the fossil record.     

Do shorebirds graze down zoobenthic biomass at the Banc d'Arguin tidal flats in Mauritania?

The 500 km² of tidal flats at the Banc d'Arguin, Mauritania, are a wintering site for over 2 million shorebirds, making this one of the areas with the highest density of shorebirds in the world. In earlier studies, it was found that these huge numbers of birds are dependent on a rather low biomass of benthic animals. To explain this paradoxical situation, we hypothesized that the earlier assessments of biomass in late winter and early spring do not reflect a year-round situation. Benthic biomass may be high when the birds arrive in autumn to be subsequently grazed down in the course of winter. To test this hypothesis, we have determined benthic biomass in September 1988. The result has been compared with a biomass value obtained in February–April 1986 with the same methods and at the same stations. These two biomass values do not differ significantly; so our hypothesis has to be rejected. It has to be admitted, however, that our experimental design cannot discern between differences due to the year of sampling and those due to the season.     

A hydrographic time series station in the Wadden Sea (southern North Sea)

In the tidal inlet between the East Frisian islands of Langeoog and Spiekeroog, southern North Sea, a time-series station was set up in autumn 2002 as part of the research programme BioGeoChemistry of Tidal Flats run by the University of Oldenburg. The purpose of the station is to provide continuous data on physical, biological and chemical parameters. In addition to instruments recording basic hydrographic and meteorological parameters, the time-series station is equipped with acoustic Doppler profilers for measuring surface waves and current profiles. Compact optical spectrometers are being used for spectral measurements of seawater transmission and for daylight reflectance. Additional sensors were installed for measuring oxygen, nutrients and methane in the seawater. The data shall help to quantify the flux of dissolved and suspended matter between the backbarrier tidal flat and the open sea and to characterise the material transformation in the tidal flat area by biogeochemical processes over the tidal cycle. Due to its novel design, operation of the station is also possible during winter and under extreme weather conditions (gales, storm surges, and sea ice) when data sampling with conventional platforms such as research vessels, buoys, or smaller poles could not be performed in the past. In this way, time series of data are obtained, which include events that are most relevant to the evolution of this coastal area. The performance of the station and its equipment are presented with data covering 6 years of operation. Time series of air and water temperature as well as seawater salinity demonstrate the multiyear dynamics of these parameters in the East Frisian Wadden Sea. Hydrographic data collected under specific meteorological conditions such as gales and storm surges exemplify the all-weather capabilities of the station and its value for studying hydrographic processes in the Wadden Sea.     

江苏条子泥岸滩剖面形态的时空异质性

在江苏条子泥岸滩选择3个典型剖面，对其进行了3a定期的观测，将所得剖面数据绘制成剖面形态曲线。通过对岸滩剖面形态的分析，发现3a来岸滩冲淤变化明显，岸滩剖面形态内部及其相互间都有变化，呈现不同的类型。探讨了其变化的机制，包括自然因素和人为因素。主要的研究结果将丰富人们对江苏条子泥近期岸滩及辐射沙洲演变的认识，为条子泥促淤并陆和海岸防护等工程提供科学依据。     

苏北近岸海域表层沉积物粒度及其对环境动力的响应

对2007年9-11月在南黄海辐射沙脊区和江苏北部潮滩采集的表层底质样品进行粒度分析,获得了平均粒径、分选系数、偏态、峰态等粒度参数,并对其进行了聚类分析。结果表明,9 m以浅和20 m以深的样品可归为两种类型的沉积物,而水深9~20 m之间的沉积物两种类型都有,多样性较大。由Gao-Collins粒径趋势分析模型获得的沉积物净输运趋势显示,除外毛竹砂处沉积物有向外海输运的趋势之外,其他外围的断面均显示泥砂向辐射沙洲中心输运,这与历史资料中记录的结果相一致,表明粒径趋势分析适用于大型辐射沙洲海域。根据Sternberg图分析,粒度参数的空间分布是由差异性输运造成,沉积物从射阳河口岸外向大丰潮间带上部输运的过程中,众数粒径几乎全部以悬移质的形式输运,而小庙洪向东灶潮滩上部输运的众数粒径以悬移方式输运的概率只有60%,从而使射阳河口岸外与大丰潮间带上部的沉积物粒度参数相同,而小庙洪与东灶潮间带上部的沉积物粒度参数有显著差异。     

Microbially induced sedimentary structures in Archean sandstones: A new window into early life

Until now, the most valuable information on the early life on the Archean Earth derived from bacterial fossils and stromatolites preserved in precipitated lithologies such as chert or carbonates. Also, shales contain complex biomarker molecules, and specific isotopes constitute an important evidence for biogeneicity.In contrast, because of their low potential of fossil preservation, sandstones have been less investigated. But recent studies revealed a variety of ‘microbially induced sedimentary structures — MISS’ that differ greatly from any other fossils or sedimentary structures. ‘Wrinkle structures’, ‘multidirected ripple marks’, ‘biolaminites’, and other macrostructures indicate the former presence of photoautotrophic microbial mats in shallow-marine to tidal paleoenvironments. The MISS form by the mechanical interaction of microbial mats with physical sediment dynamics that is the erosion and deposition by water agitation. The structures occur not only in Archean tidal flats, but in equivalent settings throughout Earth history until today.MISS are not identified alone by their macroscopic morphologies. In thin-sections, the structures display the carpet-like fabrics of intertwined filaments of the ancient mat-constructing microorganisms. Geochemical analyses of the filaments proof their composition of iron minerals associated with organic carbon.In conclusion, microbial mats colonize sandy tidal settings at least for 3.2 Ga years. Therefore, Archean sandstones constitute an important archive for the exploration of early life.     

A quantitative approach to sedimentary surface structures contoured by the interplay of microbial colonization and physical dynamics

In the tidal flats of Mellum Island (southern North Sea), biofilms and microbial mats, generated largely by cyanobacteria, colonize the sedimentary surfaces. Biostabilization effects and biomass enrichment influence erosional and depositional dynamics resulting from tidal flushing and storm surges. The overlapping of both biological and physical forces causes the development of characteristic sedimentary structures. To obtain a quantitative expression of the degree of effectiveness of microbial colonization in the formation of structures in an extended tidal area, a modification index (MOD-I) was developed based on the following values: (i) the proportion of mat-covered area related to a defined investigation area (I_A); (ii) the degree of steepness of slope angles of raised erosional remnants (I_S); and (iii) the degree of microbial levelling of a rippled sedimentary surface (I_N). The MOD-I was calculated for several defined regions within the study area, and both winter and summer situations were considered. The MOD-I values show, first, that the lower intertidal zone is characterized by index values approaching zero. This implies that microbially induced effects in this zone are negligible, even in summer. Second, the upper intertidal zone is characterized by lower index values in winter and relatively high values in summer. This implies a predominantly seasonal control on the biofilm development in this zone. Third, in the lower supratidal zone, the index values are almost identical during both winter and summer. This implies non-seasonal biological effects in this zone. Concomitant empirical studies on the composition of microbial mats and films suggest that the dominant microbial type influences the MOD-I value.