Measurement of Particle-Bound Reactive Oxygen Species in Rubidoux Aerosols   总被引：1，自引：0，他引：1  

Prasanna?Venkatachari  Philip?K.?HopkeEmail author  Brett?D.?Grover  Delbert?J.?Eatough 《Journal of Atmospheric Chemistry》2005,50(1):49-58

The diurnal variations in the concentrations of reactive oxygen species (ROS) in various size fractions were determined for ambient particles in Rubidoux, CA. Sampling of particles was conducted at 3 h intervals using a cascade impactor. The collected particles were reacted with dichlorofluorescin (DCFH), a non-fluorescent probe that fluoresces when oxidized. The factors affecting the diurnal variation in ROS concentration were also investigated with special emphasis on the relation between ROS concentration and the intensity of photochemical reactions where the ozone concentration was taken as an index. The intensity of photochemical reactions was found to be a moderate factor affecting the daytime ROS concentration. The concentration of ROS was found to be higher on the smaller particles of the ambient aerosol. An erratum to this article is available .  相似文献   

Bioenergetics modeling to investigate habitat use by the nonindigenous crab,Carcinus maenas, in Willapa Bay, Washington     

P. Sean McDonald  Kirstin K. Holsman  David A. Beauchamp  Brett R. Dumbauld  David A. Armstrong 《Estuaries and Coasts》2006,29(6):1132-1149

A bioenergetics model was developed and applied to questions of habitat use and migration behavior of nonindigenous European green crab (Carcinus maenas) in Willapa Bay, Washington, USA. The model was parameterized using existing data from published studies on the ecology and physiology ofC. maenas and allied brachyuran crabs., Simulations of the model were run describing four scenarios of habitat use and behavior during a 214-d simulation period (April–October) including crabs occupying mid littoral habitat, high littoral habitat, sublittoral habitat, and sublittoral habitat but undertaking intertidal migrations. Monthly trapping was done along an intertidal gradient in Willapa Bay to determine the actual distribution of crabs for the same time interval as the simulation period, and model results were compared to the observed pattern. Model estimates suggest no intrinsic energetic incentive for crabs to occupy littoral habitats since metabolic costs were c. 6% higher for these individuals than their sublittoral counterparts. Crabs in the littoral simulations were also less efficient than sublittoral crabs at converting consumed energy into growth. Monthly trapping revealed thatC. maenas are found predominantly in mid littoral habitats of Willapa Bay and there is no evidence of resident sublittoral populations. The discrepancy intimates the significance of other factors, including interspecific interactions, that are not incorporated into the model but nonetheless increase metabolic demand. Agonistic encounters with native Dungeness crabs (Cancer magister) may be chief among these additional costs, andC. maenas may largely avoid interactions by remaining in littoral habitats neglected by native crabs, such as meadows of nonindigenous smooth cordgrass (Spartina alterniflora). AdultC. maenas in Willapa Bay may occupy tidal elevations that minimize such encounters, and metabolic costs, while simultaneously maximizing submersion time and foraging opportunities.  相似文献   

Identification of Burrowing Shrimp Food Sources Along an Estuarine Gradient Using Fatty Acid Analysis and Stable Isotope Ratios     

Katelyn M. Bosley  Louise A. Copeman  Brett R. Dumbauld  Keith L. Bosley 《Estuaries and Coasts》2017,40(4):1113-1130

Two species of burrowing shrimp occur in high densities in US West Coast estuaries, the ghost shrimp, Neotrypaea californiensis, and the blue mud shrimp, Upogebia pugettensis. Both species of shrimp are considered ecosystem engineers as they bioturbate and irrigate extensive galleries within the sediment. While their burrows comprise a dominant habitat type in west coast estuaries, little is known about these shrimps’ diet and their role in estuarine food webs. The primary goals of this study were to identify major components of burrowing shrimp diets and detect variation in these diets along an estuarine gradient using combined fatty acid (FA) and stable isotope (SI) analyses. Shrimp and potential food sources including eelgrass blades, epiphytes, Ulva, sedimentary particulate organic matter (SPOM), burrow walls, and particulate organic material (POM) were sampled at different locations within Yaquina Bay, Oregon in August 2012. Both SI and FA analyses indicated differences in food resources assimilated by shrimp along the estuarine gradient. SI values showed that diets for U. pugettensis consisted of carbon sources derived primarily from POM and SPOM, while POM and epiphytes were primary carbon sources for N. californiensis. Shrimp from lower estuarine sites had high levels of 16:1ω7 and 20:5ω3 FAs suggesting their diet is enriched with marine diatoms. Shrimp from upriver showed greater proportion of FA associated with dinoflagellates and terrestrial sources as indicated by a high percentage of C₁₈ polyunsaturated FAs (PUFAs). This is the first study to evaluate diets of these two shrimp species using complimentary FA and SI approaches.  相似文献   

Basement-controlled deformation of sedimentary sequences,Anadarko Shelf,Oklahoma     

Folarin Kolawole  Molly Simpson Turko  Brett M. Carpenter 《Basin Research》2020,32(6):1365-1387

Structures rooted in the crystalline basement frequently control the deformation of the host bedrock and the overlying sedimentary sequences. Here, we elucidate the structure of the c. 2-km deep Precambrian granitic basement in the Anadarko Shelf, Oklahoma, and how the propagation of basement faults deformed the sedimentary cover. Although the basin is foreland in origin, the gently dipping shelf sequences experienced transpressional deformation in the Late Palaeozoic. We analyse a 3-D seismic reflection data set and basement penetrating well data in an area of 824 km². We observe: (a) pervasive deformation of the basement by basement-bounded interconnected mafic sills, and a system of subvertical discontinuity planes (interpreted as faults) of which some penetrate the overlying sedimentary cover; (b) three large (>10 km-long) through-going faults, with relatively small (<100 m) vertical separation (Vsep) of the deformed stratigraphic surfaces; (c) upward propagation of the large faults characterized by faulted-blocks near the basement, and faulted-monoclines in the deeper sedimentary units that transition into open monoclinal flexures up-section; (d) cumulative along-fault deformation of the stratigraphy exhibits systematic trends that varies with offset accrual; (e) two styles of Vsep—Depth distribution which include a unidirectional decrease of Vsep from the basement through the cover rocks (Style-1) and a bidirectional decrease of Vsep from a deep sedimentary unit towards the basement and shallower sequences (Style-2). We find that the basement-driven propagation (Style-1) shows greater efficiency of driving the fault deformation to shallower depths compared to the intrasedimentary-driven fault nucleation and propagation (Style-2). Our study demonstrates an evolution of cumulative Vsep trends with offset accrual on the faults, and the partial inheritance of the heterogeneous intra-basement deformation by the sedimentary cover. This contribution provides important insight into the upward propagation of basement-driven faulting associated with structural inheritance in contractional sedimentary basins.  相似文献   

Oxidative stress response of European flounder (Platichthys flesus) to cadmium determined by a custom cDNA microarray     

Sheader DL  Williams TD  Lyons BP  Chipman JK 《Marine environmental research》2006,62(1):33-44

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Exposure of sticklebacks (Gasterosteus aculeatus) to cadmium sulfide nanoparticles: biological effects and the importance of experimental design.   总被引：1，自引：0，他引：1  

Matthew B Sanders  Marion Sebire  Joachim Sturve  Paul Christian  Ioanna Katsiadaki  Brett P Lyons  Dave Sheahan  Jason M Weeks  Stephen W Feist 《Marine environmental research》2008,66(1):161-163

Effects of nanoparticles on aquatic organisms have been little studied to date and toxicological data are urgently needed for development of regulatory frameworks for these substances. Here, we report the findings of a study exposing sticklebacks to cadmium sulfide (CdS) as bulk material and quantum dots. Fish were exposed for 21 d in a flow through test system to 5, 50 or 500 microg l(-1) CdS nanoparticles (nCdS) coated in thiol terminated methyl polyethylene glycol (MPEG), bulk CdS or MPEG at 500 microg l(-1) (nominal concentrations). With the exception of the highest nCdS exposure, measured concentrations were approximately one order of magnitude below nominal. A single fish from each group (excluding MPEG) was examined using energy dispersive X-ray analysis (EDX) to localise cadmium, however, cadmium could not be detected in whole body sections. Elevated levels of oxidized glutathione were measured in the gills of fish exposed to 50 and 500 microg l(-1) nCdS. Induction of vitellogenin synthesis was not detected in any of the treatment groups. The number of males engaged in nest-building behaviour following exposure to 500 microg l(-1) nCdS was reduced and livers of 4/6 fish in the same treatment displayed hepatocellular nuclear pleomorphism. The results are discussed emphasising the fundamental importance of experimental design and the need to understand the behaviour of nanoparticles in the aqueous phase.  相似文献