Above- and belowground interactions drive habitat segregation between two cryptic species of tropical trees

In the lowlands of central Panama, the Neotropical pioneer tree Trema micrantha (sensu lato) exists as two cryptic species: "landslide" Trema is restricted to landslides and road embankments, while "gap" Trema occurs mostly in treefall gaps. In this study, we explored the relative contributions of biotic interactions and physical factors to habitat segregation in T. micrantha. Field surveys showed that soils from landslides were significantly richer in available phosphorus and harbored distinct arbuscular mycorrhizal fungal (AMF) communities compared to gap soils. Greenhouse experiments designed to determine the effect of these abiotic and biotic differences showed that: (1) both landslide and gap species performed better in sterilized soil from their own habitat, (2) the availability of phosphorus and nitrogen was limiting in gap and landslide soils, respectively, (3) a standardized AMF inoculum increased performance of both species, but primarily on gap soils, and (4) landslide and gap species performed better when sterilized soils were inoculated with the microbial inoculum from their own habitat. A field experiment confirmed that survival and growth of each species was highest in its corresponding habitat. This experiment also showed that browsing damage significantly decreased survival of gap Trema on landslides. We conclude that belowground interactions with soil microbes and aboveground interactions with herbivores contribute in fundamental ways to processes that may promote and reinforce adaptive speciation.     

Assessment of coastal storm impacts on contaminant body burdens of oysters collected from the gulf of Mexico

This study evaluated changes in oyster tissue contaminant levels following North Atlantic tropical cyclones to determine if changes in contaminant concentrations were predictable. The basis for this study was analysis of coastal chemical contaminant data from the National Oceanic and Atmospheric Administration's (NOAA) National Status and Trends Mussel Watch Program and NOAA's National Weather Service storm track data. The tendency for contaminant (metals and organic compounds) body burdens to increase or decrease in oyster tissue after a storm was assessed using contingency and correspondence analyses. Post-storm contaminant levels in oysters revealed a consistent pattern of distribution, which could be described as follows: (1) most of the organic contaminants stay within their long-term concentration ranges, (2) very few organic contaminants decreased, and (3) metals overwhelmingly tend to increase.     

Measuring RNA:DNA ratios in individual <Emphasis Type="Italic">Acartia tonsa</Emphasis> (Copepoda)

Acartia tonsa Dana is a dominant copepod in coastal waters and is therefore an important link in the food web between microplankton and higher trophic levels. RNA:DNA ratios have been used to describe growth and nutritional condition of field-collected copepods and to show strong correlation between RNA:DNA ratios and group egg production (EP). A method was developed using a sensitive, nucleic acid-specific fluorescent dye, and automated microplate fluorometer to measure DNA, RNA, and the RNA:DNA ratio of individual A. tonsa. DNA, RNA, and RNA:DNA ratios and EP were all significantly higher in copepods fed Thalassiosira sp. compared to starved copepods. There was a general trend toward an increase in RNA:DNA ratios with increase in EP, but due to the high degree of variation in both RNA:DNA ratios and EP among individual copepods there was no significant correlation between RNA:DNA ratios and EP. Significant differences in RNA:DNA ratios between fed (7.2) and starved (3.3) copepods were found after 2 days. This assay may be applied to other species of copepods sampled in the field to provide an index of the health of planktonic food webs.     

Organic and Inorganic Characterization of Marine Colloids

Isolates of the organic matter in the particulate, colloidal and dissolved states were obtained by tangential flow ultrafiltration through 0.40 μm polycarbonate and ∼ 1 nm (1000 NMWL*) regenerated cellulose membranes and by solid-liquid reverse phase extraction techniques. the material was analyzed qualitatively by mass spectroscopy, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, high performance liquid chromatography with fluorescence detection of labelled primary amines and amino acids, and inductively coupled plasma/mass spectroscopy. All three states are characterized by similar organic chemistries. the marine colloidal state in coastal waters off the Californian coast contains primarily carbohydrates, fatty acids, minor amounts of proteinaceous compounds and electropositive elements including aluminium and iron. Aromatic molecules and olefinic functional groups are in low concentration. the colloidal state differs qualitatively from the particulate and dissolved states. Yet all three could be derived, with degradation, from algal or macroalgal surface components.     

爱尔兰共和国境内的湖泊调查:水化学特性和酸敏感性

1997年在爱尔兰共和国进行了一项湖泊调查活动,本活动是确定并则绘临界负载的一个国家项目的一部分内容.共选取了200个湖泊作为调查的对象,约占湖泊总数的3.3‰.这个国家中的多数湖泊位于沿海岸带边缘的偏僻、高海拔、对酸具有敏感性的地区.在湖泊化学中来自海洋的物质的输入占据了主导地位.由于在大部分集水区中存在有机土壤,约有一半的湖泊中溶解有机碳(DOC)的含量大于5mg/L.在一半的湖泊中,非海洋硫酸盐的浓度处于背景水平上(＜20μeq/L).在7‰的抽查湖泊(13个湖泊)中发现临界负载超量.但由于海盐和有机酸之间的相互干扰,对临界负载的计算仍存在着不稳定性.在这种情况下如果进行精确的估计,就需要借助于长期的湖泊与沉积化学.     

Port Pirie lead abatement Program, 1992

The Port Pirie Lead Decontamination Program commenced in 1984 with a ten year mandate. The abatement programme involves identification of children with elevated blood lead levels, house decontamination, soil treatment, general City greening, family education and support and community education. Since 1984 the smelter has also implemented substantial new environmental controls.Blood lead and air monitoring programmes as well as some investigations of recontamination are in place. The blood lead monitoring programme has shown a significant decrease in the mean blood lead levels of the children, with the magnitude of the reduction being greatest in areas remote from the smelter.The results of the air monitoring programme suggest that there has been little change in the general air lead levels in the City over the period of the abatement programme. Analysis of the data suggests that re-entrainment of lead from the contaminated areas within the City is only a small contributor to air-borne lead levels compared with that from the smelter and its environs.Sources and pathways of lead for absorption by the children in Port Pirie are discussed.     

Wildlife Disease in U.S. National Parks: Historical and Coevolutionary Perspectives

Diseases of wildlife have significant management implications in a number of lands of the U.S. National Park Service due to increasing interactions between wildlife and domestic animals. We review the paleontology, history, and coevolution of infectious diseases in North American ungulates. We provide two examples related to bovine brucellosis in bison in Yellowstone National Park and lungworm-pneumonia complex in bighorn sheep in several western national parks. These examples illustrate the difficulty of managing wild populations and their diseases in national parks and other protected areas. In some instances, human intervention may be justifiable in order to protect native populations, domestic animals, and humans from acquiring a disease.     

Dissipation of Contaminants of Emerging Concern in Biosolids Applied to Nonirrigated Farmland in Eastern Colorado

In 2007, a 1.5‐year field‐scale study was initiated by the U.S. Geological Survey to evaluate the dissipation of contaminants of emerging concern (CECs) following a first agronomic biosolids application to nonirrigated farmland. CECs with the greatest decrease in concentration in the surface biosolids at 180 days post‐application included indole, d‐limonene, p‐cresol, phenol, and skatol. CECs that were present in the largest concentration in 180‐day‐weathered biosolids included stanols, nonylphenols, bisphenol A, bis(2‐ethylhexyl) phthalate, hexahydrohexamethyl cyclopenta‐benzopyran (HHCB), and triclosan. CECs that were detected in pre‐application soil were 3‐beta coprostanol, skatol, acetophenone, beta‐sitosterol, beta‐stigmastanol, cholesterol, indole, p‐cresol, and phenol, most of which are biogenic sterols or fragrances that have natural plant sources in addition to anthropogenic sources, yet their concentrations increased (in some cases, substantially) following biosolids application. Preliminary data indicate the nonylphenols (including NPEO1, NPEO2), OPEO1, benzo[a]pyrene, diethyl phthalate, d‐limonene, HHCB, triclosan, and possibly 3‐beta coprostanol, skatol, beta‐sitosterol, cholesterol, indole, and p‐cresol, migrated downward through the soil by 468 days post‐application, but indicated little uptake by mature wheat plants. This study indicates that some CECs are sufficiently persistent and mobile to be vertically transported into the soil column following biosolids applications to the land surface, even in semiarid regions.     

Simultaneous-count models to estimate abundance from counts of unmarked individuals with imperfect detection

We developed a method to estimate population abundance from simultaneous counts of unmarked individuals over multiple sites. We considered that at each sampling occasion, individuals in a population could be detected at 1 of the survey sites or remain undetected and used either multinomial or binomial simultaneous-count models to estimate abundance, the latter being equivalent to an N-mixture model with one site. We tested model performance with simulations over a range of detection probabilities, population sizes, growth rates, number of years, sampling occasions, and sites. We then applied our method to 3 critically endangered vulture species in Cambodia to demonstrate the real-world applicability of the model and to provide the first abundance estimates for these species in Cambodia. Our new approach works best when existing methods are expected to perform poorly (i.e., few sites and large variation in abundance among sites) and if individuals may move among sites between sampling occasions. The approach performed better when there were >8 sampling occasions and net probability of detection was high (>0.5). We believe our approach will be useful in particular for simultaneous surveys at aggregation sites, such as roosts. The method complements existing approaches for estimating abundance of unmarked individuals and is the first method designed specifically for simultaneous counts.