江苏盐城上冈全瘭世颗石藻及其环境控制

盐城上冈地区全新世期间处于泥砂质潮滩环境。根据有孔虫组合分析,这套近岸潮滩沉积代表潮下带－湖间带－潮上带的一次大海退过程。本文分析了上冈村砖瓦厂采泥坑东侧SGE柱状剖面全新统的颗石藻化石,结果发现这套沉积物仅仅含Gephyrocapsa oceanica单一属种,而且丰度较低。但这个种在剖面上的丰度分布显示三分性：即自下至上为贫乏或缺失间隔、较常见间隔笔常见间隔,基本上对应于潮下带、潮间带和潮上带。一般情况下,潮坪区由海向陆水动力由强至弱,各相带的水动力条件不同,其沉积特征各异。颗石灌胳架十分细微,在海水中往往以悬乳形式搬运,并在水动力较弱时停积。所以,水动力是G.oceanica分布的直接控制因素。     

Particulate inputs to Dublin Bay and to the South Lagoon,Bull Island

There are substantial riverine and sewage particulate inputs into Dublin Bay. The main river, the R. Liffey, accounts for almost 85% of the riverine input, which amounts to 37.1 t d^–1 of SPM. The sewage input, which is discharged into the estuary, is slightly less at 35.3 t d^–1. The combined inputs deliver 17.4 t d^–1, 2.9 t d^–1and 1.2 t d^–1of particulate C, N and P, respectively, to the Bay as a whole. Although the particulate N load accounts for just 20% of the total N input, the retention of particulates within the system, and the subsequent remobilisation of N from the sediments is heavily implicated in the macroalgal blooms. A particulate mass balance of SPM, and of C, N and P for the South Lagoon showed no consistent pattern of import/export except that the fluxes of the individual elements reflected SPM load and varied with quantity rather than quality. The molar C:N ratio was around 6:1 although on occasion values approaching 3:1 were obtained, indicating very high quality and potentially labile SPM. The controlling factors in the budget appeared to be the water velocities and to a lesser extent, the SPM load, which surprisingly was no greater on a spring tide than on a neap. In this shallow, and primarily intertidal, system, wind- or wave-driven resuspension may exert more influence than predictable factors such as tidal range.     

Salt marsh harvest mouse demography and habitat use in the Suisun Marsh,California

We undertook a 2-year (2002–2004) mark–recapture study to investigate demographic performance and habitat use of salt marsh harvest mice (Reithrodontomys raviventris halicoetes) in the Suisun Marsh. We examined the effects of different wetland types and microhabitats on 3 demographic variables: density, reproductive potential, and persistence. Our results indicate that microhabitats dominated by mixed vegetation or pickleweed (Salicornia spp.) supported similar salt marsh harvest mouse densities, reproductive potential, and persistence throughout much of the year, whereas few salt marsh harvest mice inhabited upland grass-dominated microhabitats. We found that densities were higher in diked wetlands, whereas post-winter persistence was higher in tidal wetlands, and reproductive potential did not differ statistically between wetland types. Our results emphasize the importance of mixed vegetation for providing adequate salt marsh harvest mouse habitat and suggest that, despite their physiognomic and hydrological differences, both diked and tidal wetlands support salt marsh harvest mouse populations by promoting different demographic attributes. We recommend that habitat management, restoration, and enhancement efforts include areas containing mixed vegetation in addition to pickleweed in both diked and tidal wetlands. © 2011 The Wildlife Society.     

Total ecosystem carbon stocks at the marine‐terrestrial interface: Blue carbon of the Pacific Northwest Coast,United States

The coastal ecosystems of temperate North America provide a variety of ecosystem services including high rates of carbon sequestration. Yet, little data exist for the carbon stocks of major tidal wetland types in the Pacific Northwest, United States. We quantified the total ecosystem carbon stocks (TECS) in seagrass, emergent marshes, and forested tidal wetlands, occurring along increasing elevation and decreasing salinity gradients. The TECS included the total aboveground carbon stocks and the entire soil profile (to as deep as 3 m). TECS significantly increased along the elevation and salinity gradients: 217 ± 60 Mg C/ha for seagrass (low elevation/high salinity), 417 ± 70 Mg C/ha for low marsh, 551 ± 47 Mg C/ha for high marsh, and 1,064 ± 38 Mg C/ha for tidal forest (high elevation/low salinity). Soil carbon stocks accounted for >98% of TECS in the seagrass and marsh communities and 78% in the tidal forest. Soils in the 0–100 cm portion of the profile accounted for only 48%–53% of the TECS in seagrasses and marshes and 34% of the TECS in tidal forests. Thus, the commonly applied limit defining TECS to a 100 cm depth would greatly underestimate both carbon stocks and potential greenhouse gas emissions from land‐use conversion. The large carbon stocks coupled with other ecosystem services suggest value in the conservation and restoration of temperate zone tidal wetlands through climate change mitigation strategies. However, the findings suggest that long‐term sea‐level rise effects such as tidal inundation and increased porewater salinity will likely decrease ecosystem carbon stocks in the absence of upslope wetland migration buffer zones.     

An active learning approach to investigate the ecosystem of tide flats using 3D modeling and printing

ABSTRACT

This paper presents an active learning approach that focuses on practical investigation of the ecosystem of tidal flats using 3D modeling and printing for biology students in order to enhance understanding of natural selection. The learning approach for the study followed a 5-step procedure: i) learning about 3D modeling and printing, ii) exploration of the ecosystem of tidal flats, iii) 3D designing of a bird beak, iv) 3D printing of a constructed beak, and v) a natural selection simulation activity. The learning method presented in this study centered on active student exploration of the tidal flats ecosystem using 3D modeling and printing. The learning approach presented in this paper could be implicated at schools to aid in students’ understanding of natural selection as it allows students to firsthand examine simulation changes to a bird beak and benthic communities. This study suggested the active learning method for natural selection as it incorporates student-designed exploration and direct investigative appraisal of the selection process.     

Physiological and Molecular Basis of Susceptibility and Tolerance of Rice Plants to Complete Submergence

Rice plants are much damaged by several days of total submergence.The effect can be a serious problem for rice farmers in therainfed lowlands of Asia, and runs contrary to a widespreadbelief amongst plant biologists that rice is highly tolerantof submergence. This article assesses the characteristics ofthe underwater environment that may damage rice plants, examinesvarious physiological mechanisms of injury, and reviews recentprogress achieved using linkage mapping to locate quantitativetraits loci (QTL) for tolerance inherited from a submergence-tolerantcultivar FR13A. Progress towards identifying the gene(s) involvedthrough physical mapping of a dominant tolerance locus on chromosome9 is also summarized. Available physiological evidence pointsaway from responses to oxygen shortage as being inextricablyinvolved in submergence injury. An imbalance between productionand consumption of assimilates is seen as being especially harmful,and is exacerbated by strongly accelerated leaf extension andleaf senescence that are ethylene-mediated and largely absentfrom FR13A and related cultivars. DNA markers for a major QTLfor tolerance are shown to be potentially useful in breedingprogrammes designed to improve submergence tolerance.     

水淹生境下秋华柳对Cd污染土壤微生物数量及酶活性的影响

三峡库区消落带面临水淹及Cd污染双重胁迫,为探究秋华柳(Salix variegata Franch.)在水淹条件下对Cd污染土壤的修复能力,以秋华柳扦插苗为试验材料,设置正常供水(CK)和水淹组(FL)两个水分处理方式,4个Cd浓度梯度:对照组(0mg/kg)、低浓度(0.5mg/kg)、中浓度(2mg/kg)及高浓度(10mg/kg),分别对处理60 d和120 d的土壤微生物数量及酶活性变化特征进行研究。试验结果表明:(1)Cd浓度处理均未显著影响土壤微生物数量(P0.05),水淹显著降低处理60 d土壤细菌数、真菌数及处理120 d的土壤放线菌数及真菌数(P0.05)。(2)种植秋华柳显著提高处理60 d土壤细菌数量(P0.05),对土壤放线菌、真菌数量也有一定提升。(3)Cd浓度处理显著影响处理60 d土壤磷酸酶活性及处理120 d脲酶活性(P0.05),水淹显著降低处理60 d土壤磷酸酶活性及处理120 d脲酶、蔗糖酶和磷酸酶活性(P0.05)。(4)正常供水及水淹条件下,种植秋华柳对土壤酶活均有一定改善作用。种植秋华柳显著提高了处理60 d土壤磷酸酶活性以及处理120 d脲酶和蔗糖酶活性(P0.05)。研究结果表明:水淹生境中,秋华柳对Cd污染土壤微生物数量及酶活性具有改善作用,在Cd污染土壤修复方面有一定应用前景。