Distribution and conservation of Acipenser sturio L., 1758 and related species in Greek waters

Four sturgeon species have been reported to exist in Greek waters: the Atlantic sturgeon, the great sturgeon, the stellate sturgeon and the Adriatic sturgeon. The Atlantic sturgeon Acipenser sturio L., 1758 has an almost regular presence in the Evros River (Aegean Sea), and is rather rare in the Pinios and Acheloos Rivers. The great sturgeon or beluga Huso huso L., 1758 is suspected to be an occasional visitor in Greek waters, or it is a case of undocumented information. The presence of the stellate sturgeon Acipenser stellatus Pallas, 1771 has been recently verified by a specimen caught close to the Thracian shore. The Adriatic sturgeon Acipenser naccarii Bonaparte, 1836 is supposed to have its southern distribution limits in the waters around the island of Corfu, although this information has never been confirmed. The distribution of these species is obviously related to salinity, probably prohibiting the extension of other sturgeon species to the Mediterranean, except for A. sturio. The discontinuous distribution of H. huso and A. stellatus may be a result of sea-level changes, while salinity played some role in the last period of glaciation. In the marine area of the Evros River A. sturio has been economically significant until 1975, supporting a small black caviar industry. Since then, the species has become rare mainly because of overfishing, and the reduction and pollution of the Evros River, in the upstream of which some important sturgeon spawning sites have been located.Cuatro especies de esturiones han sido citadas en las aguas griegas: el esturión atlántico Acipenser sturio L., 1758, el beluga Huso huso (L., 1758), el esturión estrellado Acipenser stellatus Pallas, 1771 y el esturión del Adriático Acipenser naccarii Bonaparte, 1836. El esturión atlántico A. sturio tiene una casi regular presencia en el río Evros (mar Egeo), y es bastante raro en los ríos Pinios y Acheloos. El beluga H. huso se sospecha que es un visitante ocasional de las aguas griegas, o es un caso de información indocumentada. La presencia de esturión estrellado A. stellatus ha sido recientemente verificada con un ejemplar capturado cerca de la costa tracia. El esturión del Adriático A. naccarii se supone que tiene sus límites meridionales de distribución en las aguas alrededor de la isla de Corfú, aunque esta información nunca ha sido confirmada. La distribución de estas especies está obviamente relacionada con la salinidad, impidiendo, probablemente, la extensión de otras especies de esturiones en el Mediterráneo, con excepción de A. sturio. La distribución discontinua de H. huso y A. stellatus puede ser el resultado de cambios en el nivel del mar, mientras que la salinidad desempeñó algún papel en el último periodo glacial. En el área marina del río Evros, A. sturio ha sido económicamente significativo hasta 1975, soportando una pequeña industria de caviar. Desde entonces, la especie ha llegado a ser rara, principalmente a causa de la sobrepesca y la reducción y contaminación del río Evros, en cuya parte superior se localizaban importantes lugares de freza para el esturión.Instituto Español de Oceanografí

High Resolution Aerosol Data from MODIS Satellite for Urban Air Quality Studies

The Moderate Resolution Imaging Spectroradiometer (MODIS) provides daily global coverage, but the 10 km resolution of its aerosol optical depth (AOD) product is not suitable for studying spatial variability of aerosols in urban areas. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. Using MAIAC data, the relationship between MAIAC AOD and PM(sub 2.5) as measured by the 27 EPA ground monitoring stations was investigated. These results were also compared to conventional MODIS 10 km AOD retrievals (MOD04) for the same days and locations. The coefficients of determination for MOD04 and for MAIAC are R(exp 2) =0.45 and 0.50 respectively, suggested that AOD is a reasonably good proxy for PM(sub 2.5) ground concentrations. Finally, we studied the relationship between PM(sub 2.5) and AOD at the intra-urban scale (10 km) in Boston. The fine resolution results indicated spatial variability in particle concentration at a sub-10 kilometer scale. A local analysis for the Boston area showed that the AOD-PM(sub 2.5) relationship does not depend on relative humidity and air temperatures below approximately 7 C. The correlation improves for temperatures above 7 - 16 C. We found no dependence on the boundary layer height except when the former was in the range 250-500 m. Finally, we apply a mixed effects model approach to MAIAC aerosol optical depth (AOD) retrievals from MODIS to predict PM(sub 2.5) concentrations within the greater Boston area. With this approach we can control for the inherent day-to-day variability in the AOD-PM(sub 2.5) relationship, which depends on time-varying parameters such as particle optical properties, vertical and diurnal concentration profiles and ground surface reflectance. Our results show that the model-predicted PM(sub 2.5) mass concentrations are highly correlated with the actual observations (out-of-sample R(exp 2) of 0.86). Therefore, adjustment for the daily variability in the AOD-PM(sub 2.5) relationship provides a means for obtaining spatially-resolved PM(sub 2.5) concentrations

Ozone exposure assessment in a southern California community.

An ozone exposure assessment study was conducted in a Southern California community. The Harvard ozone passive sampler was used to monitor cohorts of 22 and 18 subjects for 8 weeks during the spring and fall of 1994, respectively. Ozone exposure variables included 12-hr personal O3 measurements, stationary outdoor O3 measurements from a continuous UV photometer and from 12-hr Harvard active monitors, and time-activity information. Results showed that personal O3 exposure levels averaged one-fourth of outdoor stationary O3 levels, attributable to high percentages of time spent indoors. Personal O3 levels were not predicted well by outdoor measurements. A random-effect general linear model analysis indicated that variance in personal exposure measurements was largely accounted for by random error (59-82%), followed by inter-subject (9-18%) and between-day (9-23%) random effects. The microenvironmental model performs differently by season, with the regression model for spring cohorts exhibiting two times the R2 of the fall cohorts (R2 = 0.21 vs. 0.09). When distance from the stationary monitoring site, elevation, and traffic are taken into account in the microenvironmental models, the adjusted R2 increased almost twofold for the fall personal exposure data. The low predictive power is due primarily to the apparent spatial variation of outdoor O3 and errors in O3 measurements and in time-activity records (particularly in recording the use of air conditioning). This study highlights the magnitude of O3 exposure misclassification in epidemiological settings and proposes an approach to reduce exposure uncertainties in assessing air pollution health effects

The effect of outdoor fungal spore concentrations on daily asthma severity.

The relationship between day-to-day changes in asthma severity and combined exposures to community air pollutants and aeroallergens remains to be clearly defined. We examined the effects of outdoor air pollutants, fungi, and pollen on asthma. Twenty-two asthmatics ages 9-46 years were followed for 8 weeks (9 May-3 July 1994) in a semirural Southern California community around the air inversion base elevation (1,200 ft). Daily diary responses included asthma symptom severity (6 levels), morning and evening peak expiratory flow rates (PEFR), and as-needed beta-agonist inhaler use. Exposures included 24-hr outdoor concentrations of fungi, pollen, and particulate matter with a diameter < 10 microns (PM10; maximum = 51 micrograms/m3) and 12-hour day-time personal ozone (O3) measurements (90th percentile = 38 ppb). Random effects longitudinal regression models controlled for autocorrelation and weather. Higher temperatures were strongly protective, probably due to air conditioning use and diminished indoor allergens during hot, dry periods. Controlling for weather, total fungal spore concentrations were associated with all outcomes: per minimum to 90th percentile increase of nearly 4,000 spores/m3, asthma symptom scores increased 0.36 (95% CI, 0.16-0.56), inhaler use increased 0.33 puffs (95% CI, -0.02-0.69), and evening PEFR decreased 12.1 l/min (95% CI, -1.8-22.3). These associations were greatly enhanced by examining certain fungal types (e.g., Alternaria, basidiospores, and hyphal fragments) and stratifying on 16 asthmatics allergic to tested deuteromycete fungi. There were no significant associations to low levels of pollen or O3, but inhaler use was associated with PM10 (0.15 inhaler puffs/10 micrograms/m3; p < 0.02). These findings suggest that exposure to fungal spores can adversely effect the daily respiratory status of some asthmatics