ALBERT

Description: To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the distribution and diversity of chironomid species using surface sediments of 59 lakes from the Andes to the Amazon (0.1–17°S and 64–78°W) within the Neotropics. We assess the spatial variation in community assemblages and identify the key variables influencing the distributional patterns. The relationships between environmental variables (pH, conductivity, depth, and sediment organic content), climatic data, and chironomid assemblages were assessed using multivariate statistics (detrended correspondence analysis and canonical correspondence analysis). Climatic parameters (temperature and precipitation) were most significant in describing the variance in chironomid assemblages. Temperature and precipitation are both predicted to change under future climate change scenarios in the tropical Andes. Our findings suggest taxa of Orthocladiinae, which show a preference to cold high-elevation oligotrophic lakes, will likely see range contraction under future anthropogenic-induced climate change. Taxa abundant in areas of high precipitation, such as Micropsectra and Phaenopsectra , will likely become restricted to the inner tropical Andes, as the outer tropical Andes become drier. The sensitivity of chironomids to climate parameters makes them important bio-indicators of regional climate change in the Neotropics. Furthermore, the distribution of chironomid taxa presented here is a vital first step toward providing urgently needed autecological data for interpreting fossil chironomid records of past ecological and climate change from the tropical Andes. Chironomids are sensitive environmental indicators and have been used extensively across the Northern Hemisphere to monitor aquatic ecosystems, however, research at lower latitudes has lagged behind. Here we present the distribution and diversity of lentic chironomids in the Neotropics. This data provides a foundation for using chironomids as bioindicators for future change, and urgently needed autecological information for the interpretation of fossil chironomid paleoecological records from the region.

Description: ABSTRACT The Zebrafish Model Organism Database (ZFIN; http://zfin.org ) is the central resource for genetic and genomic data from zebrafish ( Danio rerio ) research. ZFIN staff curate detailed information about genes, mutants, genotypes, reporter lines, sequences, constructs, antibodies, knockdown reagents, expression patterns, phenotypes, gene product function, and orthology from publications. Researchers can submit mutant, transgenic, expression, and phenotype data directly to ZFIN and use the ZFIN Community Wiki to share antibody and protocol information. Data can be accessed through topic-specific searches, a new site-wide search, and the data-mining resource ZebrafishMine ( http://zebrafishmine.org ). Data download and web service options are also available. ZFIN collaborates with major bioinformatics organizations to verify and integrate genomic sequence data, provide nomenclature support, establish reciprocal links and participate in the development of standardized structured vocabularies (ontologies) used for data annotation and searching. ZFIN-curated gene, function, expression, and phenotype data are available for comparative exploration at several multi-species resources. The use of zebrafish as a model for human disease is increasing. ZFIN is supporting this growing area with three major projects: adding easy access to computed orthology data from gene pages, curating details of the gene expression pattern changes in mutant fish, and curating zebrafish models of human diseases. This article is protected by copyright. All rights reserved.

Description: At least half of the world's population resides in the coastal zone and the livelihoods of billions of people are affected either directly or indirectly by the production and sustainability of nearshore fisheries. Landscape change, specifically development of tree plantations, is accelerating worldwide as developing countries integrate into global markets to sell goods, offer climate-mitigation services (carbon), and/or provide renewable energy. These changes can release excess nutrients into adjacent coastal waters causing eutrophication that alters the structure and function of coastal ecosystems. This study examined the relationship between coastal drainage basin land use/ land cover change (LCLUC), specifically development of tree plantations, patterns of chlorophyll a in nearshore coastal waters, and the biological condition of commercially important shellfish, Concholepas concholepas ( loco ) in southern Chile. Locos (N= 1,374) were sampled across 13 watersheds (35,853 km 2 ) and 42 fisheries management areas (spanning 250 km of coastline). Locos harvested from management areas influenced by tree plantations had approximately 30% more endobiont (shell-boring) phoronids, almost twice as many endobiont polychaetes and twice as many epibiont (shell-attaching) barnacles than locos from areas in close proximity to watersheds dominated by native forests (15-20% of the watershed). Phoronid infested locos from coastal waters adjacent to watersheds with tree plantations were of relatively poor biological condition (smaller and narrower in width) and of reduced market value. Our study suggests that tree plantations result in indirect ecological impacts to coastal fisheries (more nutrients and higher phytoplankton biomass, resulting in smaller, low quality locos), and costs are born by coastal fishers (lower prices for locos). Increases in tree plantations could thus potentially significantly impact coastal fisheries worldwide and such problems should be managed as an interconnected network of land use change, oceanic ecosystems, and economic systems that are considered an integrated socio-ecological system.

Description: At least half of the world's population resides in the coastal zone and the livelihoods of billions of people are affected either directly or indirectly by the production and sustainability of nearshore fisheries. Landscape change, specifically development of tree plantations, is accelerating worldwide as developing countries integrate into global markets to sell goods, offer climate-mitigation services (carbon), and/or provide renewable energy. These changes can release excess nutrients into adjacent coastal waters causing eutrophication that alters the structure and function of coastal ecosystems. This study examined the relationship between coastal drainage basin land use/land cover change (LCLUC), specifically development of tree plantations, patterns of chlorophyll- a in nearshore coastal waters, and the biological condition of commercially important shellfish, Concholepas concholepas ( loco ) in southern Chile. Locos ( N  = 1374) were sampled across 13 watersheds (35 853 km 2 ) and 42 fisheries management areas (spanning 250 km of coastline). Locos harvested from management areas influenced by tree plantations had approximately 30% more endobiont (shell-boring) phoronids, almost twice as many endobiont polychaetes and twice as many epibiont (shell-attaching) barnacles than locos from areas in close proximity to watersheds dominated by native forests (15–20% of the watershed). Phoronid infested locos from coastal waters adjacent to watersheds with tree plantations were of relatively poor biological condition (smaller and narrower in width) and of reduced market value. Our study suggests that tree plantations result in indirect ecological impacts to coastal fisheries (more nutrients and higher phytoplankton biomass, resulting in smaller, low quality locos), and costs are born by coastal fishers (lower prices for locos). Increases in tree plantations could thus potentially significantly impact coastal fisheries worldwide and such problems should be managed as an interconnected network of land use change, oceanic ecosystems, and economic systems that are considered an integrated socio-ecological system.

Description: This study addresses gaps in understanding the relative roles of sea-level change, coastal geomorphology and sediment availability in driving beach erosion at the scale of individual beaches. Patterns of historical shoreline change for spatial relationships to geomorphology and for temporal relationships to late-Holocene and modern sea-level change are examined. The study area shoreline on the north-east coast of Oahu, Hawaii, is characterized by a series of kilometres-long beaches with repeated headland-embayed morphology fronted by a carbonate fringing reef. The beaches are the seaward edge of a carbonate sand-rich coastal strand plain, a common morphological setting in tectonically-stable tropical island coasts. Multiple lines of geological evidence indicate that the strand plain prograded atop a fringing reef platform during a period of late Holocene sea-level fall. Analysis of historical shoreline changes indicates an overall trend of erosion (shoreline recession) along headland sections of beach and an overall trend of stable to accreting beaches along adjoining embayed sections. Eighty eight percent of headland beaches eroded over the past century at an average rate of -0.12 ± 0.03 m/yr. In contrast, 56% of embayed beaches accreted at an average rate of 0.04 ± 0.03 m/yr. Given over a century of global (and local) sea-level rise, the data indicates that embayed beaches are showing remarkable resiliency. The pattern of headland beach erosion and stable to accreting embayments suggests a shift from accretion to erosion particular to the headland beaches with the initiation of modern sea-level rise. These results emphasize the need to account for localized variations in beach erosion related to geomorphology and alongshore sediment transport in attempting to forecast future shoreline change under increasing sea-level rise. This article is protected by copyright. All rights reserved.

Description: We introduce a new inversion approach to constrain eruption source parameters and the distribution of tephra sedimentation from a weak plume. Our model is parameterized as a set of point sources along the plume base, whose trajectory is constrained by satellite and photographic images. Each point source releases tephra that is dispersed according to an advection-diffusion equation. This dispersion process is expressed as a system of linear equations with nonlinear dependence on diffusivity and wind speed. We employ inversion techniques to estimate the tephra mass released by each point source as well as diffusivity, stabilizing the inversion by regularization. We apply our method to the Ruapehu eruption on 17 June, 1996 in New Zealand, which was characterized by a strongly wind-advected plume that can be studied via tephra isomass measurements and particle size distributions at 119 locations. We demonstrate that the approach is feasible by performing analyses with real and synthetic data at a single grain size, and gain insight into the effects of data gaps, presence of noise, and nonlinear parameters on the inversion results. The best fit value of diffusivity yields tephra fallout that decreases steadily with distance to vent, and the predicted deposit is a good fit to the field measurements. This study illustrates the potential of a direct inversion approach to constrain diffusivity, as well as to recover the tephra fallout, without assuming a physical model for mass transport inside the plume.

Description: The Mount Givens Granodiorite, a large pluton in the central Sierra Nevada batholith, California, is similar in area to zoned intrusive suites yet is comparatively chemically and texturally homogenous. New zircon U-Pb geochronology indicates the pluton was constructed over at least 7 Ma from 97.92 ± 0.06 Ma to 90.87 ± 0.05 Ma. Combining the new geochronology with the exposed volume of the pluton yields an estimated magma flux of 〈0.001 km 3 /a. The geochronologic data are at odds with the previously speculated links between plutons such as the Mount Givens Granodiorite and large-volume homogeneous ignimbrites (often termed monotonous intermediates). Existing data indicate that large plutons accumulate at rates of ≤0.001 km 3 /a, 1-2 orders of magnitude less than fluxes calculated for dated monotonous intermediates. If monotonous intermediates are remobilized, erupted plutons accumulated at rates comparable to dated examples, they should preserve a record of zircon growth of up to 10 Ma. Alternatively, the long history of zircon growth recorded in plutons may be erased during the processes of reheating and remobilization that precede supervolcano eruption. However, zircon dissolution modeling, based on hypothetical temperature-time histories for pre-eruptive monotonous intermediates, indicates rejuvenation events would not sufficiently dissolve zircon. We suggest that eruptions of monotonous intermediates occur during high magmatic flux events, leaving little behind in the intrusive rock record, whereas low fluxes favor pluton accumulation.

Description: [1]  Weak subplinian—plinian plumes pose frequent hazards to populations and aviation, yet many key parameters of these particle-laden plumes are, to date, poorly constrained. This study recovers the particle-size-dependent mass distribution along the trajectory of a well-constrained weak plume by inverting the dispersion process of tephra fallout. We use the example of the 17 June 1996 Ruapehu eruption in New Zealand, and base our computations on mass per unit area tephra measurements and grainsize distributions at 118 sample locations. Comparisons of particle fall times and time of sampling collection, as well as observations during the eruption, reveal that particles smaller than 250μm likely settled as aggregates. For simplicity we assume that all of these fine particles fell as aggregates of constant size and density, whereas we assume that large particles fell as individual particles at their terminal velocity. Mass fallout along the plume trajectory follows distinct trends between larger particles ( d  ≥ 250μm), and the fine population ( d  〈 250μm) that are likely due to the two different settling behaviors (aggregate settling versus single-particle settling). In addition, we computed the resulting particle size distribution within the weak plume along its axis and find that the particle mode shifts from an initial 1 φ mode to a 2.5 φ mode 10 km from the vent, and is dominated by a 2.5 to3 φ mode 10–180 km from vent, where the plume reaches the coastline and we do not have further field constraints. The computed particle distributions inside the plume provide new constraints on the mass transport processes within weak plumes and improve previous models. The distinct decay trends between single particle and aggregate settling may serve as a new tool to identify particle sizes that fell as aggregates for other eruptions.

Description: Abstract Defence Science and Technology Group has developed a complete oblique incidence ionosonde system to enhance ionospheric monitoring capabilities in support of the Jindalee Operational Radar Network. The Digital Oblique Receiving System, and its counterpart, the Digital Oblique Transmitting System, feature a direct‐digital, multichannel chirp‐sounder design that allows flexible collection of high‐resolution ionograms across many simultaneous paths, without compromising dynamic range. This paper outlines the hardware and software components of the Digital Oblique Receiving System/Digital Oblique Transmitting System, including the onboard signal processing that removes radio frequency interference and fits a parameterized electron density profile to the ionogram. Additional control and data management tools that have enabled the system to be effectively transitioned into routine operations are also described. The typical performance is illustrated through a selection of sample ionograms, highlighting the applications of Digital Oblique Receiving System/Digital Oblique Transmitting System to a wide variety of ionospheric studies, including those requiring Doppler and angle‐of‐arrival observations.