Changes in seasonal and diurnal cycles of ozone and temperature in the eastern U.S.

The pollutant tropospheric ozone causes human health problems, and environmental degradation and acts as a potent greenhouse gas. Using long-term hourly observations at five US air quality monitoring surface stations we studied the seasonal and diel cycles of ozone concentrations and surface air temperature to examine the temporal evolution over the past two decades. Such an approach allows visualizing the impact of natural and anthropogenic processes on ozone; nocturnal inversion development, photochemistry, and stratospheric intrusion. Analysis of the result provides an option for determining the duration for a regulatory ozone season. The application of the method provides independent confirmation of observed changes and trends in the ozone and temperature data records as reported elsewhere. The results provide further evidence supporting the assertion that ozone reductions can be attributed to emission reductions as opposed to weather variation. Despite a (～0.5 °C decade^?1) daytime warming trend, ozone decreased by up to 6 ppb decade^?1 during times of maximum temperature in the most polluted locations. Ozone also decreased across the emission reduction threshold of 2002 by 6–10 ppb indicating that emission reductions have been effective where and when it is most needed. Longer time series, and coupling with other data sources, may allow for the direct investigation of climate change influence on regional ozone air pollution formation and destruction over annual and daily time scales.     

Cytochrome <Emphasis Type="Italic">b</Emphasis> (<Emphasis Type="Italic">Cyt-b</Emphasis>) gene sequence analysis in six flatfish species (Teleostei,Pleuronectidae), with phylogenetic and taxonomic insights

Mitochondrial DNA (mtDNA) at Cyt-b gene region was sequenced for six flatfish species (in total nine sequences of at least 1,117 bp) from the Far East of Russia and compared with other sequences of Pleuronectiformes comprising altogether 34 species and 3 outgroup species (Perciformes). Analysis of the protein-coding Cyt-b gene revealed a statistically substantiated bias in (T + C):(A + G) content, supporting earlier findings. Values of P-distances, as summarized for different scales of the evolutionary history at Cyt-b gene, revealed a clear pattern of increased nucleotide diversity at four different phylogenetic levels: (1) intraspecies, (2) intragenus, (3) intrafamily, and (4) intraorder. Scores of average P-distances of the four categories of comparison in flatfishes were (1) 0.46 ± 0.19%, (2) 11.74 ± 2.26%, (3) 17.51 ± 3.13%, and (4) 25.60 ± 0.42%, respectively (mean ± SE). These data support the concept that speciation in the order Pleuronectiformes, in most cases, follows a geographic mode through the accumulation of numerous small genetic changes over a long period of time. A phylogenetic tree for 64 sequences of flatfishes and 3 other fishes belonging to ray-finned fishes (Actinopterigii) was developed using Cyt-b gene and four different analytical approaches: neighbour-joining (NJ), Bayesian (BA), maximum parsimony (MP), and maximum likelihood (ML). The analysis revealed a monophyletic origin for the representatives of Pleuronectidae, which is the principal flatfish family investigated (99% repetition level in our BA analysis). A well supported property of the phylogenetic tree was the monophyletic placement of all the five flatfish families and the order Pleuronectiformes among other representatives of ray-finned fishes of the class Actinopterigii. Species identification on per individual basis (barcoding tagging) was generally high. However, there were taxonomic complications that arose during analysis, and they are discussed. Major outcomes of this discussion are the necessity of synonymy acceptance for Hippoglossoides elassodon, and H. robustus, and for Pseudopleuronectes yokohamae and P. schrenki. Priority considerations suggest H. elassodon and P. yokohamae as valid species names.     

Riverine fluxes of the persistent organochlorine pesticides hexachlorcyclohexane and DDT in the Russian Federation

The contribution of gross riverine organochlorine pesticide (OCP) transport to estuaries of Russian seas and Lake Baikal was determined to help understand OCP transboundary transfer and to provide a basis for estimating Russia's contribution to global pollution by these pesticides. The official OGSNK/GSN data ranks sea/ocean/lake basins in the following order based upon the amounts of total OCPs received from agricultural use: Eastern Arctic>Western Arctic>Pacific>Baltic>Caspian>Azov/Black>Baikal. A similar ranking was obtained using an independent set of data: Eastern Arctic>Pacific>Caspian>Western Arctic>Baltic>Azov/Black. In terms of riverine flow-associated discharge of HCH isomers (i.e., sum of alpha-, beta- and gamma-HCH) estuaries of the Kara, Okhotsk and Beloye (White)/Barents seas received more pesticides than other seas. No HCH was discharged to estuaries of the Eastern Siberian and Bering seas. For DDT and its derivative (DDE), estuaries of the Kara, Caspian, Okhotsk and Baltic seas received the greatest amounts. During our study period (1988-1996), HCH transport was more prevalent in the majority of rivers reflecting both the official ban on the use of DDT in the former Soviet Union and the greater popularity of HCH as a pesticide. In general, it appears that Russian rivers play a significant role in OCP contamination of some estuaries of regional seas, especially those of the eastern Arctic basin, such as the Kara Sea.