Coral Recruitment and Regeneration on a Maldivian Reef 21 Months after the Coral Bleaching Event of 1998

Abstract. This paper describes the quantitative inventory of stony corals on a Maldivian reef after the bleaching event of 1998. The detailed data, collected in March 1999 and March 2000, comprise survival, new recruitment and regenerates. They were obtained in 6 transects laid out randomly on the reef flat, on 22 Acropora tables on 6 sites at the reef edge and on 39 Porites lobata blocks and 1 Diploastrea heliopora colony. The present cover of living zooxanthellate corals is reduced to ca. 2 – 5 % of its previous state. Acroporidae and Pocilloporidae were practically wiped out, while Poritidae survived partly and Agariciidae (esp. Pavona) are now the dominant group. New settlements on dead Acropora tables were mainly Agariciidae, followed by Acroporidae and Pocilloporidae. Regenerates on Porites were pronounced and the apparent yearly increase in mass was about threefold that of Diploastrea, which is 3 – 4 mm per year. The influence on reef ecology in terms of coral substrate and species, possible sources of larvae, change of guilds in reef builders, other species and the prospect for further development of the reef, with respect to growth versus erosion, is discussed.     

Urban re-generations: afterword to special issue on the politics of urban greening in Australian cities

ABSTRACT

‘Urban re-generations' is written as an afterword to the special issue of Australian Geographer on ‘The Politics of Urban Greening in Australian Cities'. The collection prompts a deep questioning of reparative and regenerative work associated with greening, green spaces and green infrastructures. The climate-driven 2019-2020 bushfire crisis and COVID-19 have amplified the visibility of the more-than-human connectivity of our cities and the deep underlying structures of social and environmental inequity underpinning a variety of urban green spaces and agendas. Inspired by the articles in this special issue, the afterword explores how we might call back the grammars and practices of regeneration from their service to the neo-liberal, settler-colonial city and instead nurture reparative de-colonial practices that aid in the collaborative work of re-composing, becoming into better relation with, and working in modes of situated historical and cultural difference, with green and just cities.     

Ammonium regeneration in intertidal sediments of the Yangtze estuary during air-exposure

The influences of exposure to the atmosphere on ammonium cycle in the intertidal surface sediments were in situ studied with a geochemical approach at a typical station in the Yangtze Estuary during three tidal cycles in September 2003. During an about 8-h emersion period of each diurnal tide, six high-resolution vertical profiles of adsorbed and dissolved ammonium were measured. It was observed that both adsorbed and dissolved ammonium generally had an increasing trend in sediment cores during the exposure. The rate of ammonium regeneration in sediments was estimated using the accumulation amount of ammonium including adsorbed and soluble fractions during the daytime emersion. The calculation result showed that there was relatively high ammonification rate (˜500 nmol N cm⁻³ day⁻¹), which reflected that organic nitrogen in sediments was quickly decomposed with a residence time of ˜52.7 days. Due to the dramatic temperature difference observed in sediment profiles, free convection was considered an important mechanism of regulating the efflux of produced ammonium into overlying waters. The total estimated amount of regenerated ammonium was ˜1.35×10⁵ t N year⁻¹ in the intertidal flat of the Yangtze Estuary, which occupied 7.6% of the total inorganic nitrogen annually transported to the estuarine ecosystem.     

A case study on Landscape Component Niche based on Landscape Pattern Indices: Yanchi,Ningxia Province,China

Yanchi County is located in the agro-pastoral ecotone and belongs to the ecologically fragile area of Northwest China.It is important to study the evolution of landscape pattern to curb its environmental degradation.In order to intuitively show how the landscape pattern of the study area changes over time,Landsat Thematic Mappers(TM)and Landsat Operational Land Imager(OLI)data of 1991,2000,2010 and 2017 were used.This paper attempts to apply niche theories and methods into landscape ecology,and constructs a niche model of landscape components by using"n-dimentional hypervolume niche theory"and landscape pattern indices.By evaluating the spatial and temporal evolution of niche from the perspective of two-dimensional space to reflect the changes of landscape pattern in the study area over the past 26 years,new theories and methods were introduced for the characterization of landscape pattern.The results indicate that:1)The larger the attribute and dominance value of landscape components,the higher the ecological niche and the stronger the control effect on the overall landscape.2)The ecological niche of each landscape component was significantly different,just as its control effect on the overall landscape.3)The dynamic change of the ecological niche of each landscape component was different,with grassland,unused land and arable land always in a high dominant position,although the ecological niche of construction land and water area was always low.In general,the introduction of niche theory into the landscape ecology provided a new method to study the changes in regional landscape pattern.     

城市物质空间更新研究进展与展望

城市物质空间更新是城市发展的自然历史过程。转型期的中国城市,物质空间更新的速度与范围正在逐渐加大,且深度作用于社会经济空间重构过程。本文首先全面总结了国内外城市物质空间更新的相关理论与研究成果,凝练了在城市物质空间更新背景、演替脉络、更新模式及策略方面的核心思想与评判方法,总结了城市物质空间更新的成功做法和经验。其次,从城市物质空间更新的空间判定与时空组织模式、建筑资产拆损、更新模式与综合评估、影响因素与机制定量研究方面对中国未来的城市物质空间更新研究进行了展望。最后,本文认为在新型城镇化和资源节约型社会建设大背景下,有必要加强中国城市物质空间更新的系统研究、综合研究、动态研究和定量研究,进而为制定因地制宜的物质空间更新优化调控政策和方案提供依据。     

首钢京唐钢铁厂压缩空气供气系统的优化设计

通过首钢京唐钢铁厂的压缩空气供气系统的设计,探讨了在设计中所采用的优化及余热再生等节能技术,和所能达到的良好的经济效益。     

改进的模拟退火遗传算法在地下水管理中的应用

对于高度非线性、非凸的地下水管理模型,传统优化方法难以找到全局最优解。本文采用模拟退火遗传算法求解地下水管理模型,并从三个方面对算法进行改进:引入小生境技术,采用自适应交叉和变异概率,在选择过程中采用最优保存策略,从而提高算法的全局寻优能力和收敛速度。采用惩罚函数法处理约束条件。用Fortran 90语言编制了计算程序,并通过Schaffer测试函数验证了该算法不仅具有强大的全局寻优能力和局部搜索能力,而且具有较快的收敛速度和较高的优化精度。将该算法应用到某研究区地下水管理中,取得了较好的效果。     

肠鳃类三崎柱头虫再生的研究

在饲养条件下,对青岛辛岛湾潮间带的三崎柱头虫(Balanoglossus misakiensis)的栖息和再生进行研究。6条柱头虫沿生殖翼中后部自切为2段,后段失去摄食、钻洞穴等行为能力和再生前段器官的能力,生存约1个月后解体;前段在1、2天内恢复了摄食、钻洞穴等生活习性,2个月内完成了后段缺失器官的再生,最长存活时间达156d,体长能达到母体体长的一半。113个个体通过手术横切为2段、3段或4段,发现42%的含有吻、领及鳃区的前段虫体,也能够再生全部失去的其他器官;没有吻、领和鳃区的其它片段失去了再生能力。     

基于生态位理论的深莞惠旅游一体化策略研究

运用生态位理论对推进深莞惠三市旅游一体化进行分析,发现三地存在旅游资源生态位同质化和旅游产业发展生态位同向化的问题,因此要求三地厘清生态位,错位发展,开发特色旅游产品和旅游商品;扩充生态位,挖掘潜力,提供旅游发展的持续动力;分离生态位,在政府协调基础上进行旅游地分工;集中优势,共同打造跨区域特色旅游线路;建立深莞惠无障碍旅游区,巩固区域内旅游市场。     

海州湾底层鱼类物种多样性与生物量的关系

随着生物多样性的丧失,全球许多海洋生态系统的功能发生了显著变化。为了解生物多样性和生态系统功能之间的关系,科学的海洋生态保护与管理显得尤为重要。本研究根据2013−2022年春季在海州湾及其邻近海域进行的底拖网调查数据,基于结构方程模型（SEM）探究了底栖鱼类群落中环境因素、生物多样性（物种丰富度与均匀度）和生态系统功能指标（以总生物量表示）之间的关系。结果表明：物种丰富度和生物量之间存在显著的正相关,而均匀度和生物量存在显著的负相关。环境因素中盐度对物种丰富度和生物量均有显著的影响,而对于温度来说,夏季与冬季的温度比年平均温度对生物量的影响更强烈。本研究表明,生态位互补效应和选择效应这两种机制可能同时对维持海州湾底层鱼类群落中的生物多样性−生物量关系发挥了作用,此外这种关系还依赖于它们所生存的环境和栖息条件。