Local scale genetic structure in coral populations: a signature of selection

Coastal marine reserves in general, and coral reef reserves in particular, are typically composed of scattered patches separated by uninhabited areas. Due to the sessile mode of life of adult corals, larval connectivity is often the only agent of gene flow between reef localities. In this study we examined the connectivity between populations of the common scleratinian coral Stylophora pistillata at the northern tip of the Gulf of Aqaba (Red Sea), using the rDNA ITS (internal transcribed spacer) as a molecular marker. Sequence comparisons among recruits indicated very similar, equally-diverse, assemblages of recruits in both the northern (highly affected by anthropogenic disturbances) and southern (less affected) study sites, implying a high larval connectivity or common sources of larval supply. By contrast, sequence diversity observed among adults declined sharply from southern to northern sites, accompanied by genetic differentiation of the respective populations. Based on Fu's Fs-test of selective neutrality, it may be suggested that various post-settlement selective regimes, presumably more intense in the northern sites, provide a reasonable explanation for the observed patterns of genetic diversity. The suggested hypothesis is supported by the sharper decline in sequence diversity found between recruits and adults in the northern sites. This study exemplifies the necessity to consider local selective factors, in addition to larval connectivity, when managing marine reserves.     

Elements in fish of Malibu Creek and Malibu Lagoon near Los Angeles,California

Our aim was to assess whether past discharges from a wastewater treatment plant increased metal pollutant loads in stream mobile species in a one-day baseline sampling study that included a coastal wetland. Mosquitofish (Gambusia affinis) of two sizes, black bullhead (Ameiurus melas), and crayfish (Pacifastacus leniusculus) were collected from Malibu Creek, and California killifish (Fundulus parvipinnis) of three sizes, as well as arroyo chub (Gila orcutti) were sampled from Malibu Lagoon near Los Angeles, California. Species from each locality were pooled by length, homogenized, digested by microwave wet ashing, and analyzed by simultaneous inductively coupled plasma atomic emission spectroscopy for 27 elements. Lagoon killifish 2.0-3.5 cm long contained levels of arsenic and lead above the levels for 95% of California fish, the EDL95. Black bullhead upstream of the discharge contained elevated levels of As, Cr and Se. Young mosquitofish <3 cm in length upstream of the discharge differed greatly in the order of abundance of their elements relative to larger mosquitofish and to other species collected. More sampling than this baseline study allowed was needed to determine if the wastewater treatment plant was a pollution source.     

A synthesis of dominant ecological processes in intensive shrimp ponds and adjacent coastal environments in NE Australia

One of the key environmental concerns about shrimp farming is the discharge of waters with high levels of nutrients and suspended solids into adjacent waterways. In this paper we synthesize the results of our multidisciplinary research linking ecological processes in intensive shrimp ponds with their downstream impacts in tidal, mangrove-lined creeks. The incorporation of process measurements and bioindicators, in addition to water quality measurements, improved our understanding of the effect of shrimp farm discharges on the ecological health of the receiving water bodies. Changes in water quality parameters were an oversimplification of the ecological effects of water discharges, and use of key measures including primary production rates, phytoplankton responses to nutrients, community shifts in zooplankton and delta15N ratios in marine plants have the potential to provide more integrated and robust measures. Ultimately, reduction in nutrient discharges is most likely to ensure the future sustainability of the industry.     

南极洲—新西兰裂谷作用以及与洋脊俯冲和地幔柱活动相…

南极洲玛丽伯德地中部的中白垩世火成岩，记录了从与俯冲有关的岩浆作用快速转变为与裂谷有关的岩浆作用。这一转变与菲尼克斯板块俯冲的最后阶段和随后发生的新西兰从南极洲裂解这两程相联系。裂谷岩浆活动产生了多样的Ａ型花岗岩类岩石和源于岩石圈地幔的大陆溢洪玄武岩族的镁铁质侵入岩。板块边界上作用力的变化导致了裂谷作用。然在而地幔柱活动也许开始于中白垩世，它引发了岩石圈的熔融并控制了裂发育的部位。     

冲积地层三维模型理论与应用

建立了冲积地层的三维模型，在模拟过程中，认为冲积地层中粗粒河道带沉积的空间分布，比例，连通性是河道带宽度，泛平夺宽度，满岸河深，河道带与溢岸沉积速度，决口位置与周期，压实作用和构造运动的函数。模型认为泛平原表现宽度和长度变化是由单一河道带造成的，泛平原地形变化是由河道带时变化，泛平原沉积速率，压实作用，局部或区域构造运动控制的决口的位置和时间是受洪水的频率，幅度及与河道带坡度相关的泛原坡度局部变化