Monitored and modeled coral population dynamics and the refuge concept

With large-scale impacts on coral reefs due to global climatic change projected to increase dramatically, and suitability of many areas for reef growth projected to decrease, the question arises whether particular settings might serve as refugia that can maintain higher coral populations than surrounding areas. We examine this hypothesis on a small, local scale in Honduras, western Caribbean. Dense coral thickets containing high numbers of the endangered coral Acropora cervicornis occur on offshore banks while being rare on the fringing reef on nearby Roatán. Geomorphological setting and community dynamics were evaluated and monitored from 1996 to 2005. A model of population dynamics was developed to test assumptions derived from monitoring. Coral cover on the fringing reef declined in 1998 from >30% to <20%, but the banks maintained areas of very dense coral cover (32% cover by A. cervicornis on the banks but <1% on the fringing reef). Bathymetry from satellite images showed the banks to be well-separated from the fringing reef, making asexual connectivity between banks and fringing reef impossible but protecting the banks from direct land-runoff during storms. Exposure to SE tradewinds also causes good flushing. Only four A. cervicornis recruits were recorded on the fringing reef over 6 years. Runoff associated with hurricanes caused greater mortality than did bleaching in 1998 and 2005 on the fringing reef, but not on the banks. Since 1870, our analysis suggests that corals on the banks may have been favored during 17 runoff events associated with tropical depressions and storms and potentially also during five bleaching events, but this is more uncertain. Our model suggests that under this disturbance regime, the banks will indeed maintain higher coral populations than the fringing reef and supports the assumption that offshore banks could serve as refugia with the capacity to subsidize depleted mainland populations.     

中小学避难建筑规划建设标准与容灾能力研究

已知避难建筑相较于场地型避难场所更有利于中长期避难,而目前我国城镇避难场所建设以场地型为主,建筑型避难场所存在严重不足。基于此,首先提出将中小学校舍建设为建筑型避难场所的重要性及可行性,并从空间利用角度对其可作为避难建筑的类型进行分析研究,指出中小学体育馆、食堂、宿舍和教室可建设为避难建筑;其次对我国城镇地区现状中小学校舍能够作为避难建筑的容灾能力进行分析,结果表明:现状满足100%的短期灾时避难人口的避难需求,以及满足60%的中长期灾时避难人口的避难需求;最后通过计算进行预测,可知随着城镇人口的增长,其所需的避难规模能够在日常城镇中小学校舍建设更新中逐步实现,大约需要未来20年时间基本可以实现中等规模灾害建筑型避难,大灾害长期避难能够满足100%的中长期灾时避难人口的避难需求,具有规划规模可实现性和可行性。     

Influence of a rock glacier spring on the stream energy budget and cold‐water refuge in an alpine stream

The thermal regimes of alpine streams remain understudied and have important implications for cold‐water fish habitat, which is expected to decline due to climatic warming. Previous research has focused on the effects of distributed energy fluxes and meltwater from snowpacks and glaciers on the temperature of mountain streams. This study presents the effects of the groundwater spring discharge from an inactive rock glacier containing little ground ice on the temperature of an alpine stream. Rock glaciers are coarse blocky landforms that are ubiquitous in alpine environments and typically exhibit low groundwater discharge temperatures and resilience to climatic warming. Water temperature data indicate that the rock glacier spring cools the stream by an average of 3 °C during July and August and reduces maximum daily temperatures by an average of 5 °C during the peak temperature period of the first two weeks in August, producing a cold‐water refuge downstream of the spring. The distributed stream surface and streambed energy fluxes are calculated for the reach along the toe of the rock glacier, and solar radiation dominates the distributed stream energy budget. The lateral advective heat flux generated by the rock glacier spring is compared to the distributed energy fluxes over the study reach, and the spring advective heat flux is the dominant control on stream temperature at the reach scale. This study highlights the potential for coarse blocky landforms to generate climatically resilient cold‐water refuges in alpine streams.     

Attractiveness of a lateral shelter in a channel as a refuge for juvenile brown trout during hydropeaking

Peak power production in hydroelectric storage power plants results in frequent and intense flow variations in the rivers downstream of the plants. Fish populations can be negatively impacted when subjected to these so-called hydropeaking phenomena. In researching mitigation solutions, shelters in the riverbanks of channelized rivers have been identified as a means of protecting fish from excessive flow velocities. These shelters were studied systematically using juvenile brown trout (Salmo trutta fario) in an experimental configuration in which a straight channel was equipped with a lateral embayment. The purpose of the experiments was to generate hydrodynamic hydropeaking conditions in the channel that are undesirable for juvenile trout, thereby causing them to enter the shelter. The flow velocity distribution in the intersection plane between the main channel and the lateral shelter was found to be a significant parameter for attracting fish to the shelter. The utilization rate of trout in the shelter was used as a performance indicator. Using a basic rectangular shelter configuration without forced water exchange between the shelter and the channel, the utilization rate was only 35 %. This rate was more than doubled by introducing a deviation groyne to force water exchange between the channel and the shelter. The position and orientation angle of this groyne were systematically varied to maximize the utilization rate. Maximum utilization rates approaching 90 % were obtained for an optimum configuration in which an island-type groyne was placed in the shelter. The results of the systematic channel tests showed the potential of the shelter to attract fish. Such a shelter could be used in channelized rivers both for morphological revitalization and to improve fish habitats. As a next step in this research, prototype shelters will be built on a natural river and monitored for 2–3 years under a hydropeaking flow regime.     

The role of the hyporheic zone for a benthic fish in an intermittent river: a refuge, not a graveyard

In lotic systems, the hyporheic zone has been suggested as a potential refuge for aquatic organisms during disturbances (hyporheic refuge hypothesis). However, the supporting evidence is unclear, especially regarding the survival of hyporheic refugees and their contribution to the recovery of post-disturbance populations. Moreover, few studies have focused on the importance of the hyporheic refuge for aquatic vertebrates such as fish. In this study, we present evidence that the hyporheic zone acts as a refuge for a small benthic fish (Cobitis shikokuensis) following surface drying in an intermittent river. We examined its survival during and recolonization after dry periods by direct hyporheic sampling and mark-and-recapture surveys. When the streambed dried, hyporheic sampling was conducted 58 times across 33 locations in the intermittent reach and 31 individuals of C. shikokuensis were captured from extracted hyporheic water. Mark-and-recapture surveys revealed that recolonizers after re-wetting included C. shikokuensis individuals that had survived dry periods in the hyporheic refuge. The condition factor of C. shikokuensis significantly declined after dry periods, suggesting that most recolonizers suffered from physiological stress, probably within the hyporheic refuge. These results clearly support the long-debated, hyporheic refuge hypothesis, and provide a striking example of the critical role of the hyporheic zone in population maintenance of lotic organisms.     

新泽5井水位趋势下降分析

新泽5井水位1997年以来呈趋势下降动态,至2002年底下降幅度达970mm。为解释该趋势下降的原因,首先对深州市及其周边地区地热开采点的空间分布及地下热水开采量进行了详细调查,而后对华北油田采油和注水情况进行了了解。经调查研究表明,新泽5井1997年以来,水位的趋势下降,水位动态年变规律的改变,是井区及附近地区大量开采地下热水引起的。     

8 没有资金就没有进展

到目前为止,那些在《自然》杂志上关于地震预测研究争论的意见非常清楚地表明,对于地震破裂如何起始及如何预测它这一问题,我们几乎还没能触及其皮毛。这是由于该问题很困难和缺乏一个强有力的计划来研究它。正如ＡｎｄｒｅｗＭｉｃｈａｅｌ所说,在美国对地震预测研究...     

11 没有进展就没有资金

Wyss认为如果没有在规模上与天文物理研究资金可比的资金,则不可能取得学会预测地震的切实进展".可是,在一些国家的若干地区所作的广泛和预测努力皆失败了.除非有明确的和令人信服的研究课题认为所提出的新预测计划将会是成功的,进一步的政府基金资助看来才有保证.     

江苏苏05井、苏06井水温近年来典型异常特征分析及其机理讨论

近10年历史震例的分析表明,江苏苏05井、苏06井水温观测资料异常与江苏及邻省中等地震有很好的对应关系。本文对2010年后两口井的观测数据进行分析,总结了苏05井、苏06井水温测项在震前的典型异常特征:①异常表现为打破上升趋势的下降变化;②震前异常持续时间为2-3个月左右,映震范围在300km左右;③两口井的震前异常幅度在0.003℃左右。根据总结的异常特征并结合水温与井孔结构关系、水温与水位的关系、不同层位水温观测原理以及水化分析结果等,对异常可能的成因进行了初步探讨。     

APPLIED GEOPHYSICS, Vol.2, No.1 - No.4 Contents in total(2005)

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乌鲁木齐10号泉流量的映震分析

从监测泉点的水地质概况入手，结合近16年来的震例，分析并总结了10号泉流量的映震特征：流量的地震前兆异常基本上都是正异常，且具有较好的重复性，即流量测值遵循背景值一趋势性上升（或突升）－最高值一趋势性下降（或突降）一恢复到背景值。而地震常常发生在流量测值由高变低的过程中，最后，初步认定了泉点较好地地震构造环境是造成该泉流量具有映震灵敏性的原因。     

No evidence for thermogenic methane release in coal from the Karoo-Ferrar large igneous province

The Early Jurassic Toarcian oceanic anoxic event (T-OAE) and concurrent negative carbon-isotope (δ¹³C) excursion have recently been attributed to either the release of methane (CH₄) clathrates or thermogenic CH₄ gas associated with the Karoo-Ferrar large igneous province (LIP) into coals and organic-rich shales. ¹²C-enriched thermogenic CH₄ production associated with the Karoo-Ferrar would result in residual material being ¹²C-depleted nearer the intrusions. In this study, geochemical analyses (carbon isotopes, volatile matter (VM), vitrinite reflectance (R_o)) are reported for two coal transects associated with dykes intruding the No. 4L coal in the Highveld Coalfield, Karoo Basin, South Africa. VM decreases from over 35% to around 15% in one transect, and the second transect shows a less pronounced decrease (from > 25% to ~ 16%). Accompanying the decrease in VM content is an increase in R_o from background levels of around 0.7% to over 4% adjacent to the dyke; used as a palaeo-geothermometer, R_o values indicate background temperatures of ~ 100 °C increasing to > 300 °C close to the contact. Despite changes in VM and R_o, there are no significant changes in δ¹³C, certainly not of the magnitude that would be expected associated with large-scale thermogenic CH₄ generation. These and other Gondwanan coals have low vitrinite and liptinite contents (components more prone to CH₄ generation), in part explaining the modest decreases in VM adjacent to the dykes. This, combined with the relatively narrow metamorphic aureole surrounding the intrusions and the likelihood that at least some of the volatiles generated by the intrusion were trapped as coalbed CH₄ or condensed as pyrolytic carbon, suggests only limited CH₄ release. In addition, based on original estimates of moisture contents in these coals and the depth at time of intrusion (1,000–2,000 m) the dykes would have lost most of their energy heating and evaporating water, thus having very little remaining energy to generate thermogenic CH₄.     

2016年衡水冀16井水位变化分析

衡水冀16井水位2016年经常出现有规律的大幅度异常波动变化,具有小幅下降—持续上升—小幅上升—持续下降变化形态,日变最大幅度0.73 m。通过现场核实,发现观测仪器工作正常,附近鱼场地下水开采量增加。增加辅助观测仪器同井对比水位观测,并对鱼场2口冷水井进行抽水试验,分析衡水冀16井水位异常变化原因。结果显示,衡水冀16井水位大幅波动异常变化可能因冷水井1抽水所致,冷水井2无影响。