1,266 research outputs found
Offshore Distances of Bowhead Whales (Balaena mysticetus) Observed during Fall in the Beaufort Sea, 1982–2000: An Alternative Interpretation
Nineteen years (1982– 2000) of sighting data from fall aerial surveys of bowhead whales (Balaena mysticetus) in the Alaskan Beaufort Sea were analyzed to determine how patterns in the distribution of migrating bowhead whales relate to annual sea-ice conditions. Transect sighting rate (transect sightings/km) indicated (ANOVA; F2, 980 = 143.84, p < 0.0001) that bowhead whales occurred farther offshore in years of heavy ice conditions (73.4 km, 95% CL: 67.2–79.6 km) than in years of moderate (49.3 km, 95% CL: 44.8–53.84 km), or light (31.2 km, 95% CL: 30.0–32.4 km) ice conditions. The most plausible explanation for the observed pattern in bowhead whale distribution is that in years of heavy ice conditions (annual pack ice; 1983, 1988, 1991), the developing landfast ice limits availability of shallow nearshore habitat, thus necessitating use of leads and ice openings in deeper water. We acknowledge that factors such as bathymetry, ocean currents, transport, and food availability may also interact to influence autumn distribution of bowhead whales. In heavy ice years, however, these factors likely exert less influence on bowhead whale distribution than in years with light to moderate ice conditions.Les données automnales prélevées à partir de relevés aériens pendant 19 années chez les baleines boréales (1982– 2000) (Balaena mysticetus) de la mer de Beaufort alaskienne ont été analysées dans le but de déterminer comment les tendances caractérisant la répartition des baleines boréales en migration se rapportent à l’état annuel des glaces et de la mer. Le taux de repérage transect (repérage transect/km) a indiqué (ANOVA; F2, 980 = 143.84, p < 0,0001) que les baleines boréales se trouvaient plus loin au large pendant les années où il y avait beaucoup de glace (73,4 km, 95 % CL: 67,2–79,6 km) que pendant les années où la glace était modérée (49,3 km, 95 % CL: 44,8–53.84 km) ou légère (31,2 km, 95 % CL: 30,0–32,4 km). L’explication la plus plausible à la source de la tendance qui a été observée en matière de répartition des baleines boréales, c’est que pendant les années où il y a beaucoup de glace (banquise; 1983, 1988, 1991), la glace de rive en formation limite la disponibilité d’habitats de faible profondeur à proximité du littoral, ce qui nécessite l’utilisation de chenaux et d’ouvertures dans la glace en eau plus profonde. On reconnaît que des facteurs comme la bathymétrie, les courants océaniques, le transport et la disponibilité de la nourriture peuvent également entrer en interaction au point d’exercer une influence sur la répartition automnale des baleines boréales. Cependant, pendant les années où il y a beaucoup de glace, ces facteurs sont susceptibles d’exercer moins d’influence sur la répartition des baleines boréales que pendant les années où la couverture de glace varie de légère à moyenne
Spectral variability of the particulate backscattering ratio
The spectral dependency of the particulate backscattering ratio is relevant in the fields of ocean color inversion, light field modeling, and inferring particle properties from optical measurements. Aside from theoretical predictions for spherical, homogeneous particles, we have very limited knowledge of the actual in situ spectral variability of the particulate backscattering ratio. This work presents results from five research cruises that were conducted over a three-year period. Water column profiles of physical and optical properties were conducted across diverse aquatic environments that offered a wide range of particle populations. The main objective of this research was to examine the behavior of the spectral particulate backscattering ratio in situ, both in terms of its absolute magnitude and its variability across visible wavelengths, using over nine thousand 1-meter binned data points for each of five wavelengths of the spectral particulate backscattering ratio. Our analysis reveals no spectral dependence of the particulate backscattering ratio within our measurement certainty, and a geometric mean value of 0.013 for this dataset. This is lower than the commonly used value of 0.0183 from Petzold\u27s integrated volume scattering data. Within the first optical depth of the water column, the mean particulate backscattering ratio was 0.010
The AP-3 Adaptor Complex Is Essential for Cargo-Selective Transport to the Yeast Vacuole
AbstractThree distinct adaptor protein (AP) complexes involved in protein trafficking have been identified. AP-1 and AP-2 mediate protein sorting at the trans-Golgi network and plasma membrane, respectively, whereas the function of AP-3 has not been defined. A screen for factors specifically involved in transport of alkaline phosphatase (ALP) from the Golgi to the vacuole/lysosome has identified Apl6p and Apl5p of the yeast AP-3 complex. Deletion of each of the four AP-3 subunits results in selective mislocalization of ALP and the vacuolar t-SNARE, Vam3p (but not CPS and CPY), while deletion of AP-1 and AP-2 subunits has no effect on vacuolar protein delivery. This study, therefore, provides evidence that the AP-3 complex functions in cargo-selective protein transport from the Golgi to the vacuole/lysosome
Use of Early Ripening Cultivars to Avoid Infestation and Mass Trapping to Manage \u3cem\u3eDrosophila suzukii\u3c/em\u3e (Diptera: Drosophilidae) in \u3cem\u3eVaccinium corymbosum\u3c/em\u3e (Ericales: Ericaceae)
Use of early ripening highbush blueberry cultivars to avoid infestation and mass trapping were evaluated for managing spotted wing drosophila, Drosophila suzukii (Matsumura). Fourteen highbush blueberry cultivars were sampled for spotted wing drosophila infestation. Most ‘Earliblue’, ‘Bluetta’, and ‘Collins’ fruit were harvested before spotted wing drosophila oviposition commenced, and so escaped injury. Most fruit from ‘Bluejay’, ‘Blueray’, and ‘Bluehaven’ were also harvested before the first week of August, after which spotted wing drosophila activity led to high levels of blueberry infestation. In a separate experiment, damage to cultivars was related to the week in which fruit were harvested, with greater damage to fruit observed as the season progressed. Attractant traps placed within blueberry bushes increased nearby berry infestation by 5%, irrespective of cultivar and harvest date. The significant linear reduction in infestation with increasing distance from the attractant trap suggests that traps are influencing fly behavior to at least 5.5 m. Insecticides applied to the exterior of traps, compared with untreated traps, revealed that only 10-30% of flies visiting traps enter the traps and drown. Low trap efficiency may jeopardize surrounding fruits by increasing local spotted wing drosophila activity. To protect crops, traps for mass trapping should be placed in a perimeter outside fruit fields and insecticides need to be applied to the surface of traps or on nearby fruit to function as an attract-and-kill strategy
Dispersal Modeling of Fish Early Life Stages: Sensitivity with Application to Atlantic Cod in the Western Gulf of Maine
As an initial step in establishing mechanistic relationships between environmental variability and recruitment in Atlantic cod Gadhus morhua along the coast of the western Gulf of Maine, we assessed transport success of larvae from major spawning grounds to nursery areas with particle tracking using the unstructured grid model FVCOM (finite volume coastal ocean model). In coastal areas, dispersal of early planktonic life stages of fish and invertebrate species is highly dependent on the regional dynamics and its variability, which has to be captured by our models. With state-of-the-art forcing for the year 1995, we evaluate the sensitivity of particle dispersal to the timing and location of spawning, the spatial and temporal resolution of the model, and the vertical mixing scheme. A 3 d frequency for the release of particles is necessary to capture the effect of the circulation variability into an averaged dispersal pattern of the spawning season. The analysis of sensitivity to model setup showed that a higher resolution mesh, tidal forcing, and current variability do not change the general pattern of connectivity, but do tend to increase within-site retention. Our results indicate strong downstream connectivity among spawning grounds and higher chances for successful transport from spawning areas closer to the coast. The model run for January egg release indicates 1 to 19 % within-spawning ground retention of initial particles, which may be sufficient to sustain local populations. A systematic sensitivity analysis still needs to be conducted to determine the minimum mesh and forcing resolution that adequately resolves the complex dynamics of the western Gulf of Maine. Other sources of variability, i.e. large-scale upstream forcing and the biological environment, also need to be considered in future studies of the interannual variability in transport and survival of the early life stages of cod
Sucrose Improves Insecticide Activity Against Drosophila suzukii (Diptera: Drosophilidae)
The addition of sucrose to insecticides targeting spotted wing drosophila, Drosophila suzukii (Matsumura), enhanced lethality in laboratory, semifield, and field tests. In the laboratory, 0.1% sucrose added to a spray solution enhanced spotted wing drosophila feeding. Flies died 120 min earlier when exposed to spinosad residues at label rates enhanced with sucrose. Added sucrose reduced the LC50 for dried acetamiprid residues from 82 to 41 ppm in the spray solution. Laboratory bioassays of spotted wing drosophila mortality followed exposure to grape and blueberry foliage and/or fruit sprayed and aged in the field. On grape foliage, the addition of 2.4 g/liter of sugar with insecticide sprays resulted in an 11 and 6% increase of spotted wing drosophila mortality at 1 and 2 d exposures to residues, respectively, averaged over seven insecticides with three concentrations. In a separate experiment, spinetoram and cyantraniliprole reduced by 95-100% the larval infestation of blueberries, relative to the untreated control, 7 d after application at labeled rates when applied with 1.2 g/liter sucrose in a spray mixture, irrespective of rainfall; without sucrose infestation was reduced by 46-91%. Adding sugar to the organically acceptable spinosyn, Entrust, reduced larval infestation of strawberries by >50% relative to without sugar for five of the six sample dates during a season-long field trial. In a small-plot field test with blueberries, weekly applications in alternating sprays of sucrose plus reduced-risk insecticides, spinetoram or acetamiprid, reduced larval infestation relative to the untreated control by 76%; alternating bifenthrin and phosmet (without sucrose) reduced infestation by 65
Comparison of a Synthetic Chemical Lure and Standard Fermented Baits for Trapping Drosophila suzukii (Diptera: Drosophilidae)
We determined the attractiveness of a new chemical lure compared with fermented food baits in use for trapping Drosophila suzukii Matsumura, spotted wing drosophila (Diptera: Drosophilidae), in Connecticut, New York, and Washington in the United States and at Dossenheim in Germany. The chemical lure (SWD lure) and food baits were compared in two types of traps: the dome trap and a cup trap. Regardless of trap type, numbers of male and female D. suzukii trapped were greater with the SWD lure compared with apple cider vinegar (ACV) baits at the Washington and New York sites, and were comparable with numbers of D. suzukii captured with a wine plus vinegar bait (W + V) at Germany site and a combination bait meant to mimic W + V at the Connecticut site. Averaged over both types of attractants, the numbers of D. suzukii captured were greater in dome traps than in cup traps in New York and Connecticut for both male and female D. suzukii and in Washington for male D. suzukii. No such differences were found between trap types at the Washington site for female and Germany for male and female D. suzukii. Assessments were also made of the number of large (>0.5 cm) and small (<0.5 cm) nontarget flies trapped. The SWD lure captured fewer nontarget small flies and more large flies compared with ACV bait in New York and fewer nontarget small flies compared with W + V in Germany, although no such differences were found in Washington for the SWD lure versus ACV bait and in Connecticut for the SWD lure versus the combination bait, indicating that these effects are likely influenced by the local nontarget insect community active at the time of trapping. In New York, Connecticut, and Germany, dome traps caught more nontarget flies compared with cup traps. Our results suggest that the four-component SWD chemical lure is an effective attractant for D. suzukii and could be used in place of fermented food-type bait
FVCOM validation experiments : comparisons with ROMS for three idealized barotropic test problems
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C07042, doi:10.1029/2007JC004557.The unstructured-grid Finite-Volume Coastal Ocean Model (FVCOM) is evaluated using three idealized benchmark test problems: the Rossby equatorial soliton, the hydraulic jump, and the three-dimensional barotropic wind-driven basin. These test cases examine the properties of numerical dispersion and damping, the performance of the nonlinear advection scheme for supercritical flow conditions, and the accuracy of the implicit vertical viscosity scheme in barotropic settings, respectively. It is demonstrated that FVCOM provides overall a second-order spatial accuracy for the vertically averaged equations (i.e., external mode), and with increasing grid resolution the model-computed solutions show a fast convergence toward the analytic solutions regardless of the particular triangulation method. Examples are provided to illustrate the ability of FVCOM to facilitate local grid refinement and speed up computation. Comparisons are also made between FVCOM and the structured-grid Regional Ocean Modeling System (ROMS) for these test cases. For the linear problem in a simple rectangular domain, i.e., the wind-driven basin case, the performance of the two models is quite similar. For the nonlinear case, such as the Rossby equatorial soliton, the second-order advection scheme used in FVCOM is almost as accurate as the fourth-order advection scheme implemented in ROMS if the horizontal resolution is relatively high. FVCOM has taken advantage of the new development in computational fluid dynamics in resolving flow problems containing discontinuities. One salient feature illustrated by the three-dimensional barotropic wind-driven basin case is that FVCOM and ROMS simulations show different responses to the refinement of grid size in the horizontal and in the vertical.For this work, H. Huang and G. Cowles
were supported by the Massachusetts Marine Fisheries Institute (MFI)
through NOAA grants DOC/NOAA/NA04NMF4720332 and DOC/
NOAA/NA05NMF472113; C. Chen was supported by NSF grants
(OCE0234545, OCE0606928, OCE0712903, OCE0732084, and
OCE0726851), NOAA grants (NA160P2323, NA06RG0029, and
NA960P0113), MIT Sea grant (2006-RC-103), and Georgia Sea grant
(NA26RG0373 and NA66RG0282); C. Winant was supported through
NSF grant OCE-0726673; R. Beardsley was supported through NSF
OCE—0227679 and the WHOI Smith Chair; K. Hedstrom was supported
through NASA grant NAG13– 03021 and the Arctic Region Supercomputing
Center; and D. Haidvogel was supported through grants ONR N00014-
03-1-0683 and NSF OCE 043557
Traps of multi-level governance. Lessons from the implementation of the Water Framework Directive in Italy
During recent decades, different patterns of multi-level governance (MLG) have spread across Europe as a consequence of Europeanisation of public policies, which have increasingly adopted decentralized and participatory procedures conceived as a tool of more effective and accountable policy-making. It appears, however, that the implementation of operational designs based on MLG may be rather problematic and it does not necessarily bring to the expected performance improvements. Referring to the case of the EU Water Framework Directive (2000/60/EC), which conceives the creation of new multi-level institutional settings as a key tool for enacting a new holistic approach to water management and protection, this article explores the difficulties that the implementation of such settings has brought in Italy, despite some favorable pre-conditions existing in the country. Evidence is provided that along with institutional and agency variables, the implementation effectiveness of MLG arrangements promoted by the EU can be challenged by their inherent characteristics
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