Stations In Autumn Research Articles

ARTHROSPIRA-C space flight experiment: Validation of biomass and oxygen production bioprocesses using ground model demonstrator system

The Micro-Ecological Life Support System Alternative (MELiSSA) project of the European Space Agency develops a biological recycling loop for manned long-term space flight. The air revitalisation and food production are carried out by vascular plants and a photobioreactor containing the cyanobacterium Limnospira indica. In the space flight experiment ARTHROSPIRA-C, cultures of L. indica are run in a one-week batch mode (45 μmol photons m-2 s-1) followed by four semi-continuous cycles of two weeks length. Each cycle has a different, predefined light intensity following an increasing regime (45-55-70-80 μmol photons m-2 s-1). In this study, two ground science verification tests (SVT and δ-SVT) were conducted in a laboratory setting to test the reliability and functionality of the hardware- and software of ARTHROSPIRA-C. The SVT explored all four cycles and light intensities and δ-SVT was an additional test where only cycle 1 and 2 were performed. δ-SVT was used to investigate anomalies during SVT. These experiments revealed oxygen production rates between 0.10 ± 0.03 and 0.45 ± 0.01 mmol O2 L-1 h-1 and biomass production rates between 0.008 ± 0.000 and 0.021 ± 0.002 g L-1 h-1 while demonstrating sustained photosynthetic activity at all tested light intensities. In addition, proteomics analysis revealed interesting light intensity-induced effects on multiple pathways, whereas the lipidomic analysis reported no alterations. This study delves into the ground tests conducted during ARTHROSPIRA-C, paving the way for a forthcoming successful flight experiment scheduled aboard the International Space Station in autumn 2024.

A coupling methodology of the analytic hierarchy process and entropy weight theory for assessing coastal water quality.

Rapid economic development in coastal areas has gradually increased the risk of coastal water quality deterioration. The assessment methods of coastal water quality are multifarious, but many depend on either subjective judgment or objective calculation. We proposed a weighted sum methodology by integrating the subjective analytic hierarchy process and objective entropy theory (AHP-entropy weight methodology) to obtain an overall evaluation of coastal water quality. The mathematical models to transform the biochemical and physical parameter values and soluble substance concentrations into index scores have been formulated in comparison to the national water quality classification scheme. The application of the AHP-entropy weight methodology was demonstrated in the nearshore area of Yangjiang city, China, based on 23 seawater sampling stations in autumn 2017 and spring 2018. Datasets including biochemical and physical parameters, nutrients, and heavy metals have been converted into water quality index scores based on the proposed mathematical model. Results revealed that the overall water quality fell into the "good" class in both sampling seasons. The spatial distribution of the water quality index scores demonstrated that the relatively worse water quality occurred in estuarine and nearshore areas, signifying the negative effect of coastal anthropogenic activities. The statistical analyses like the hierarchical cluster analysis interpreted that the river input acted as a main source of pollutants in the study area. The AHP-entropy weight methodology could be a preferred way to assist decision-makers in properly evaluating the current state of coastal water quality in an unbiased, objective manner.

Study fish assemblages of Intertidal flats in Iraqi marine water

The seasonal study of tidal fish assemblages in Iraqi marine waters, which lasted from January 2016 to December 2016, selected three stations for the first station name Fao Head and the second station Al-Gamouri and the third station for the Western waves Breaker, recorded the highest temperature in the second station and reached to 27c.While the highest salinity concentration was recorded at the second station at 43ppt, a total of 2221 fish havecollected 40 species belonging to 28 families and 8 orders were recorded in three study stations and the highest number of species reached to 35 species in the second and third stations in autumn. The Photopectoralis bindus species dominate the highest number of individuals in autumn season reached to 284 fish in the second station, the maximum number of species reached to 33 species in summer at all the three stations. From the multivariate analysis, it was observed that the number of species was significantly correlated with some ecological factor with a total number of species and individuals.

Increasing Storage Battery Lifetime in Autonomous Photovoltaic Systems with Power Generation Structure Varying Throughout the Year

This paper substantiates the use of photovoltaic systems with power generation structure varying throughout the year. This research topic emerged from an in-depth analysis of the operating modes of autonomous photovoltaic systems located in Siberia and the Russian Far East. The paper gives a detailed and concise description of a methodology for modelling such a system with account of issues relating to the operational sustainability of diesel and solar power stations in autumn and winter. In spring and summer, autonomous photovoltaic systems operate using the standard power accumulation algorithm whereas the diesel power station serves as a stand-by power source thereby increasing the lifetime of storage batteries, reducing the number of their replacements and cutting down costs through discounting. The overall levelized cost of energy drops off significantly too. The paper presents the results of modelling an actual autonomous energy system in which a solar power station equipped with storage batteries is planned to be constructed in the near future. The modelling results revealed that using a structure varying throughout the year increases storage battery lifetime from 6 to 11 years, and there is only one (instead of three) replacement throughout the life of the batteries. The obtained results have been taken into consideration and are to be put into practice in setting up the photovoltaic system under review. The presented approach is versatile and can be used to analyze various photovoltaic systems.

Spatio-temporal variability of precipitation over the Western Balkan countries and its links with the atmospheric circulation patterns

Temporal and spatial variability of annual and seasonal precipitation from 71 stations located in Western Balkan (WB) countries (Serbia, Bosnia and Herzegovina, and Montenegro) and their correlations with nine atmospheric circulation patterns was examined for the period 1950-2016. Annual precipitation increased significantly throughout the WB (from 2% to 8% per decade) on 20% of stations located mainly in the mountainous western Serbia and eastern Bosnia and Herzegovina. Winter was characterized by non?significant precipitation changes in most of the studied area, with only a few stations characterized by significant precipitation increase (up to 12% per decade) in the mountainous area of WB, and a few stations characterized by significant decrease (up to -6% per decade) in the Pannonian plain. Significant precipitation increase was noticed on 15% of the stations in spring, while it was noticed on 17% of the stations in autumn. Summer precipitation decreased significantly (up to -5% per decade) on a limited area of northern Serbia (6% of the stations), while the majority of stations showed non?significant increase. The strongest influences on annual precipitation in WB region are of the Arctic Oscillation (AO) and Mediterranean Oscillation (MO), leading to the precipitation decrease during their positive phases. Winter precipitation is significantly negatively correlated with AO, East Atlantic/Western Russia oscillation (EA/WR), and North Atlantic Oscillation (NAO) and has a significant positive correlation with Western Mediterranean Oscillation (WeMO) on the majority of stations. MO has the strongest influence on summer precipitation in WB region leading to precipitation decrease, while AO has the dominant influence on precipitation in the region during autumn.

Ecological water health assessment using benthic macroinvertebrate communities (case study: the Ghezel Ozan River in Zanjan Province, Iran).

Macroinvertebrates are without spinal cord living organisms that spend their main phases of metamorphosis in water; so, changing the ecological structure of their communities represents environmental health condition. The main purpose of this study was to identify the macroinvertebrate families as a biological indicator and, consequently, determining the water ecological quality in the Ghezel Ozan River, NW Iran. The sampling was conducted at 18 stations in autumn 2017. At the same time, dissolved oxygen, temperature, turbidity, electrical conductivity, fecal and total coliform, BOD5, COD, phosphate, nitrate, nitrite, ammonia, chloride, and sulfate were measured based on APHA in each station. Then, based on the collected data, the NSFWQI, IRWQIsc, EQR, and BMWP/ASPT indices were calculated. In total, 1778 individual belong to 12 orders and 22 families were identified, which the most abundant order was Ephemeroptera by 47.8%. Except for the pH, COD, DO, and nitrogen compounds, other studied parameters were exceeded from their acceptable level. It seems that the geological characteristics are very effective in changing the parameters especially salinity. The best water quality was at Kharmaneh-Sar station (7), which runs from the protected area at high altitudes without human pressure. Also, the trend of water quality decreases from the upstream to downstream, which is completely in line with human activities. Therefore, the results of this study can well illustrate the role of land use and geology changes on the macroinvertebrate communities, which can be used to evaluate the ecological integrity of the river. Regular monitoring of river water quality and controlling and managing the quantity and quality of fish farms along the river can help in the ecological health of the river.

Water Mass Control on Phytoplankton Spatiotemporal Variations in the Northeastern East China Sea and the Western Tsushima Strait Revealed by Lipid Biomarkers

AbstractContinental margin ecosystems in the western North Pacific Ocean are subject to strong climate forcing and anthropogenic impacts. To evaluate mechanisms controlling phytoplankton biomass and community structure variations in marginal sea‐open ocean boundary regions, brassicasterol, dinosterol, and C37 alkenones were measured in suspended particles in summer and autumn from 2012 to 2013 in the northeastern East China Sea and the western Tsushima Strait. In summer, the concentrations of brassicasterol (40–1535 ng/L) and dinosterol (4.2–94 ng/L) were higher in the southwest of Cheju Island, while C37 alkenones (0–30 ng/L) were higher in the south of Cheju Island. In autumn, brassicasterol (12–106 ng/L), dinosterol (2.4–21 ng/L), and C37 alkenones (0.7–7.0 ng/L) were higher in the southwest of Cheju Island and the western Tsushima Strait, and higher C37 alkenones also occurred in the Okinawa Trough. Correlation analysis of biomarkers and environmental conditions (temperature, salinity, and inorganic nutrient concentrations) clearly demonstrated that phytoplankton biomass and community structure variations can be well elucidated by water masses as indexed by temperature and salinity. High nutrients from the Changjiang River were the main cause of high biomass in summer, while nutrients from subsurface water were likely the key factor regulating phytoplankton biomass in open ocean water stations in autumn. This study indicates that mechanisms controlling phytoplankton biomass in marginal sea‐open ocean boundary regions should be classified by various water masses with different nutrient concentrations, instead of by geography.

Seasonal variations in macrobenthic taxonomic diversity and the application of taxonomic distinctness indices in Bohai Bay, northern China

Taxonomic diversity indices have a number of desirable properties as indicators in the assessment of environmental quality, and have become an important measure in biodiversity studies. Macrobenthic taxonomic variations were studied in Bohai Bay, northern China, an area under threat from rapid human development. Four seasonal cruise datasets were collected between 2006 and 2007. Environmental conditions exhibited large fluctuations due to human development; nitrogen and phosphorus were the main environmental stressors. A total of 97 macrofauna taxa were identified belonging to 88 genera, 72 families, 36 orders, 14 classes, and nine phyla. Analysis of similarity indicated that there were significant assemblage differences across sampling stations as well as seasons. Four taxonomic indices, taxonomic diversity (Δ), taxonomic distinctness (Δ*), average taxonomic distinctness (Δ+), and variation in taxonomic distinctness (Λ+) were calculated using abundance data. Among the stations and seasons, there were greater variations in both Δ and Λ+ than in Δ* and Δ+. The funnel plot of Δ+ could identify disturbed stations to some extent, but was not always a strong indicator of disturbance. The Δ+ performance was better in autumn than in spring, but could not identify a disturbed station in autumn due to a low number of species. The efficiency of taxonomic distinctness may depend on taxa or the pollution indicators. Taxonomic distinctness indices can be effective at assessing environmental degradation when correctly applied; however, they are unsuitable for directly assessing environmental quality in a new area prior to efficiency testing.

State-dependent foraging: lactating voles adjust their foraging behavior according to the presence of a potential nest predator and season.

Parental care often produces a trade-off between meeting nutritional demands of offspring and the duties of offspring protection, especially in altricial species. Parents have to leave their young unattended for foraging trips, during which nestlings are exposed to predators. We investigated how rodent mothers of altricial young respond to risk of nest predation in their foraging decisions. We studied foraging behavior of lactating bank voles (Myodes glareolus) exposed to a nest predator, the common shrew (Sorex araneus). We conducted the experiment in summer (high resource provisioning for both species) and autumn (less food available) in 12 replicates with fully crossed factors “shrew presence” and “season.” We monitored use of feeding stations near and far from the nest as measurement of foraging activity and strategic foraging behavior. Vole mothers adapted their strategies to shrew presence and optimized their foraging behavior according to seasonal constraints, resulting in an interaction of treatment and season. In summer, shrew presence reduced food intake from feeding stations, while it enhanced intake in autumn. Shrew presence decreased the number of visited feeding stations in autumn and concentrated mother’s foraging efforts to fewer stations. Independent of shrew presence or season, mothers foraged more in patches further away from the nest than near the nest. Results indicate that females are not investing in nest guarding but try to avoid the accumulation of olfactory cues near the nest leading a predator to the young. Additionally, our study shows how foraging strategies and nest attendance are influenced by seasonal food provision.

Trophic ecology of Lampanyctus crocodilus on north-west Mediterranean Sea slopes in relation to reproductive cycle and environmental variables.

This study examined the population structure, reproductive cycle and feeding pattern of the lanternfish Lampanyctus crocodilus in the Balearic Basin (north-west Mediterranean Sea) from a depth of 450 to 1800 m and at a seasonal scale. Juveniles were mainly located at shallower depths, but also at deepest stations in autumn, while adults mostly inhabited intermediate depths with their centre of population density (CPD) located at 800-1000 m of depth. The migration of adults to deeper depths was detected in late summer to autumn, probably linked to the occurrence of nepheloid layers at c. 1200 m, which in turn enhances the biomass of the zooplankton prey. The diet was mainly based on euphausiids and mysids, with marked seasonal variations both on the upper (450-800 m) and lower (1000-1800 m), where suprabenthic gammariids and pelagic decapods were also dominant. Stomach fullness increased from winter to autumn on the US, while it had a maximum in spring on the LS, in parallel with high consumption of gelatinous zooplankton, which is probably more available after the phytoplankton bloom in late winter. Reproduction occurred in winter, confirmed by the higher percentage of mature females and high gonadosomatic indices (I(G)) at both depth ranges. Hepatosomatic indices (I(H)) showed an inverse trend to I(G) on the US, except in autumn, and was almost parallel on the LS, probably attributable to the migration of adults, which determined different temporal schemes in energy use and storage for reproduction on the US v. LS. Consistent with the different patterns observed at the two depth ranges, environmental drivers of fullness (i.e. feeding intensity) and I(G) (as a proxy of reproductive cycle) differed on the US and LS. The biomass of mysids and euphausiids was the greatest explanatory variables of fullness on the US and LS, pointing to the increasing feeding intensity when a resource was more available. I(H) also explained fullness, suggesting that greater feeding intensity in pre-reproductive periods enabled energy storage in the liver. I(G) was linked directly (i.e. mysids) or indirectly (i.e. surface primary production recorded 2 months before sampling) to food availability, implying a rapid response to vertical food inputs by deep-sea predators. Also, I(G) in L. crocodilus was related to population density, which suggests aggregations for reproduction. Estimates of L. crocodilus trophic levels, and of other accompanying mesopelagic fishes, indicated that the species feed through a continuum spanning the third trophic level, confirming the key role of mesopelagic fishes in transferring organic carbon between trophic levels. Trophic niche segregation among mesopelagic species was pronounced and non-overlapping groups could be distinguished because of the different vertical distribution and migratory behaviour. The study highlights the important role of the benthic boundary layer in sustaining benthopelagic communities in the deep Mediterranean Sea and the need to study the biology of a species throughout its whole depth range and not just at exploited depths (i.e. fishing grounds).

Trends of mean annual and seasonal discharges of rivers in Serbia

Subjects of this paper are trends of annual and seasonal water discharges in Serbia. Data of water discharges at the 94 hydrological stations in the period 1961-2010 were analyzed, using the Mann-Kendall test and Sen's method. It was concluded that 27% of analyzed stations have statistically significant changes on annual level and 14-24% on seasonal level. The annual, winter, spring and summer trends are negative, while positive trends occur at only one station for annual values, on many stations in autumn and at a small number of stations in winter. Considering the quality of data, the results of the Beli Drim River basin require additional research, while negative trends at stations downstream of water reservoirs, primarily in basins of Južna Morava and Drina rivers, are consequences of human activities. Results show that the attention of the competent water management authorities should be directed to the Timok and Južna Morava basins in terms of the expected decrease of amounts of water, and to the basins of Toplica, Nisava, Pusta, Ibar and Kolubara rivers when it comes to increase of amounts of water.

A study to discriminate local, urban and regional source contributions to the particulate matter concentrations in the city of Dresden, Germany

The fractions of local traffic (LT), urban background (UBG) and regional background (RBG) of the particle pollution at a traffic-influenced kerbside in Dresden, Germany, were determined by measurements of size-segregated mass concentration, chemical composition and particle size distributions in a network of five measurement stations partly existing and partly set up for this study. Besides the kerbside station, one urban background site and three rural sites were included in the study. Using data from these different sites, the LT, UBG, and RBG contributions were calculated, following the approach of Lenschow et al. (2001). At the kerbside site, 19% of the total number concentration (DpSt = 10–600 nm) could be attributed to the RBG, 15% to the UBG, and 66% to the LT immediately nearby. Particle mass concentrations up to Dpaer = 420 nm RBG amounts to 68%, UBG to 21%, and LT only to 11%. Highest mass concentrations were observed at all stations in autumn and winter during easterly inflow directions. The local traffic fraction of PM10 mass at the kerbside station was found to be 30% for westerly inflow, but only 7% for southeasterly inflow due to the dominating transport fraction from up to 80% of the particle mass at this inflow direction. Size-resolved investigation showed the main fractions in both the particle size ranges of Dpaer = 0.42 to 1.2 and 0.14 to 0.42 μm at all stations. The main components sulphate, ammonium and total carbon showed higher concentrations at south-eastern/eastern inflow in autumn at all stations, while nitrate at the kerbside and urban background site was higher during westerly inflow in winter. The chemical composition at the regional background site at westerly inflow (12% nitrate, 8% sulphate, 11% total carbon) was significantly different from that at easterly inflow (3% nitrate, 15% sulphate, 22% total carbon). The prevailing part of the ionic mass was always found in the fine particle range of Dpaer = 0.14 to 1.2 μm at all stations. For all inflow directions highest total carbon concentrations were observed at the kerbside station, especially in the ultra-fine size range of Dpaer = 0.05 to 0.14 μm with up to 30% of the whole carbon. PAH concentrations were always higher at south-eastern/eastern inflow especially during wintertime. Trace metal components and silicon were found mainly in the coarse mode fraction at the kerbside resulting from abrasion or resuspension.

Changes in the probability of extreme daily precipitation observed from 1951 to 2002 in the Iberian Peninsula

AbstractIn this study trends in the probability of extreme rainfall in the Iberian Peninsula at a daily scale from 1951 to 2002 have been analysed. A simple statistical model of daily precipitation based on the gamma distribution is applied to data from 22 stations in the Iberian Peninsula from 1951 to 2002. The Mann–Kendall test was applied to look for trends of the distribution parameters. It is shown that the scale parameter remains stable, while the shape parameter is most variable, spatially and temporally, with significant negative trends in many stations. As a consequence, the trend of the probability of daily rainfall lesser than the 5th percentile is positive, mainly to the north and to the south of the Iberian Peninsula; meanwhile the probability of daily rainfall higher than the 95th percentile is negative. This behaviour, with slight spatial differences, is observed in the four seasons of the year. Results corresponding to the probability of heavy rainfalls are confirmed using the stretched exponential distribution. The possible influence of teleconnection patterns (North Atlantic Oscillation, East Atlantic, Mediterranean Oscillation pattern) is analysed calculating the correlation coefficients between teleconnection indices and the gamma distribution parameters. The winter NAO index shows significant relationships with the scale parameter, but not with the shape parameter. The East Atlantic pattern shows significant correlation coefficients with the shape parameter of 5 stations in winter, and 5 stations in autumn, but these results are not conclusive. These results suggest that the decrease of this parameter, and the behaviour of extreme rainfall probabilities, must be explained by other mechanisms. Copyright © 2009 Royal Meteorological Society

Effects of air pollution on precipitation in Kraków (Cracow), Poland in the years 1971–2005

Daily precipitation data from the period 1971–2005 from four stations in and around Krakow (Cracow), Poland (one urban and three rural ones) were analysed in order to find out whether the 80% decrease in air pollution after 1989 had an impact on the atmospheric precipitation amount and spatial distribution. The analyses were performed for the whole 35-year series and in two 17-year sub-periods: 1972–1988 (high air pollution) and 1989–2005 (low air pollution). No decreasing or increasing trend in the precipitation totals at the particular stations studied in the period 1971–2005 has been observed. The precipitation totals from 1972–1988 differ significantly from the ones of 1989–2005 only in case of Igolomia (one of the rural stations) in winter and at the urban station in autumn. The spatial pattern of precipitation did not change after 1989. The changes in air pollution affected the spatial pattern of days with precipitation mainly in spring and autumn for daily totals above 5 mm.

Spatial distribution of fungal microflora in the sediment of a brackish lake (Lake Alimini Grande, Italy) used for fish production and bathing.

A study of the distribution of fungal microflora was conducted on the sediment of Lake Alimini Grande in order to contribute to the evaluation of the ecosystem characteristics that can effect the process of decomposition. The isolation and identification of fungal species and ergosterol analysis were performed on sediment samples taken from 33 monitoring stations in autumn and winter. Altogether, 24 strains belonging to 8 genera were isolated. Trichoderma spp (41.6%) and Aspergillus spp (20.8%) were the dominant genera: in particular, Trichoderma was present near the Traugnano marsh, whereas Aspergillus was isolated in the area of connection to the sea.

Partitioning the effects of changes in nitrate availability and phytoplankton community structure on relative nitrate uptake

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 359:51-68 (2008) - DOI: https://doi.org/10.3354/meps07417 Partitioning the effects of changes in nitrate availability and phytoplankton community structure on relative nitrate uptake Jesús M. Mercado1,*, Teodoro Ramírez1, Dolores Cortés1, Marta Sebastián2, Esperanza Liger3, Begoña Bautista2 1Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, Puerto Pesquero s/n, Apdo. 285, 29640 Fuengirola (Malaga), Spain 2Departamento de Ecología, Universidad de Málaga, Facultad de Ciencias, Campus Universitario de Teatinos, 29074 Malaga, Spain 3Departamento de Física Aplicada II, Universidad de Málaga, E.T.S.I. Informática, Campus de Teatinos s/n, 29071 Malaga, Spain *Email: jesus.mercado@ma.ieo.es ABSTRACT: The uptake of dissolved nitrogen by different assemblages of phytoplankton was determined during 4 seasonal surveys carried out in the northwest sector of the Alboran Sea. The study area was characterized by stratification of the water column from spring to autumn, leading to very low nutrient concentrations in the euphotic zone; in particular, nitrate was below the detection limit at numerous stations in autumn. In winter and spring, the potential limitation of phytoplankton growth by nitrate was alleviated at some stations by upwelling of the nutrient-enriched Levantine Intermediate Water (LIW). The values of relative NO3– uptake (the proportion of nitrate to total N uptake) were highly variable (ranging from 0.01 to 0.8), even during single surveys. At most of the sampling stations during the stratification period, the relative nitrate uptake was <0.2 at the surface, but increased at the depth of the sub-surface chlorophyll a fluorescence maximum (SFM). At the surface, relative nitrate uptake and nitrate concentrations were strongly correlated, and about 82% of the relative nitrate uptake variability was accounted for by simultaneous changes in the nitrate concentrations and the micro-plankton chlorophyll a size fractions. These changes were related to modifications in upwelling intensity, as determined by variability in surface salinity. In contrast, relative nitrate uptake was not correlated with nitrate concentrations in the SFM samples, where the mean nitrate concentration increased 3-fold with respect to the surface value. On average, the micro-phytoplankton in these samples collected at the SFM was dominated by diatoms, the abundance of which ranged from 24 to 960 cells ml–1. This variability in diatom cell abundance explained about 52% of the variability of relative nitrate uptake at this depth level. Therefore, our data demonstrate that the proposed relationship between relative nitrate uptake and large phytoplankton was most evident at non-limiting nitrate concentrations. KEY WORDS: Nitrogen uptake · Diatoms · Phytoplankton · Primary production · Upwelling · Alboran Sea · Mediterranean Sea Full text in pdf format PreviousNextCite this article as: Mercado JM, Ramírez T, Cortés D, Sebastián M, Liger E, Bautista B (2008) Partitioning the effects of changes in nitrate availability and phytoplankton community structure on relative nitrate uptake. Mar Ecol Prog Ser 359:51-68. https://doi.org/10.3354/meps07417 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 359. Online publication date: May 05, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

Feeding and egg production of the planktonic copepod Calanus sinicus in spring and autumn in the Yellow Sea, China

Shipboard incubations were conducted in spring (April) and autumn (October/November) 2006 to measure the feeding and egg production rates (EPR) of Calanus sinicus in the Yellow Sea, China. The ingestion rate (2.08-11.46 and 0.26-3.70 mu g C female(-1) day(-1) in spring and autumn, respectively) was positively correlated with microplankton carbon concentrations. In the northern part of the Yellow Sea, feeding on microplankton easily covers the respiratory and production requirements, whereas in the southern part in spring and in the frontal zone in autumn, C. sinicus must ingest alternative food sources. Low ingestion rates, no egg production and the dominance of the fifth copepodite (CV) stage indicated that C. sinicus was in quiescence inside the Yellow Sea Cold Bottom Water (YSCBW) area in autumn. Calanus sinicus ingested ciliates preferentially over other components of the microplankton. The EPR (0.16-12.6 eggs female(-1) day(-1) in spring and 11.4 eggs female(-1) day(-1) at only one station in autumn) increased with ciliate standing stock. Gross growth efficiency (GGE) was 13.4% (3-39%) in spring, which was correlated with the proportion of ciliates in the diet. These results indicate that ciliates have higher nutrient quality than other food items, but the low GGE indicates that the diet of C. sinicus is nutritionally incomplete.

Trends in daily rainfall in the Iberian Peninsula from 1951 to 2002

AbstractAn analysis of 22 sites of daily precipitation records over the period 1951–2002 for the Iberian Peninsula is presented. Annual and seasonal total precipitation (P), number of wet days (N), precipitation intensity (I), the 95th percentile (P95), and percentage of rain falling on days with rainfall above the 95th percentile (%) are investigated. The annual and seasonal trends for these variables and for all 22 rain gauges are analysed, using the Mann–Kendall statistic, and a linear regression model. Moreover, a t‐test is applied to the difference between the means of two subperiods, respectively 1951–1976 and 1977–2002. Principal results indicate a decreasing trend in P, I, and P95 for several northern and southern stations in winter; P, I, and P95 in some southern stations in spring, I and P95 in some southern stations in summer, and I in some northern and southern stations in autumn. The general behaviour is a decrease in the daily intensity of rainfall, while the number of wet days does not reveal pronounced changes. This pattern is valid for both annual and seasonal values of the indices. The decreasing trend found for I in winter and annual series for some localities may be related to the predominance of the positive phase of the North Atlantic Oscillation (NAO), but it is necessary to find other mechanisms for those stations and seasons not linked directly to NAO. Copyright © 2006 Royal Meteorological Society.

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

Abstract. An Analysis of Covariance (ANCOVA) was used to derive the influence of the meteorological variability on the daily maximum ozone concentrations at 12 low-elevation sites north of the Alps in Switzerland during the four seasons in the 1992–2002 period. The afternoon temperature and the morning global radiation were the variables that accounted for most of the meteorological variability in summer and spring, while other variables that can be related to vertical mixing and dilution of primary pollutants (afternoon global radiation, wind speed, stability or day of the week) were more significant in winter. In addition, the number of days after a frontal passage was important to account for ozone build-up in summer and ozone destruction in winter. The statistical model proved to be a robust tool for reducing the impact of the meteorological variability on the ozone concentrations. The explained variance of the model, averaged over all stations, ranged from 60.2% in winter to 71.9% in autumn. The year-to-year variability of the seasonal medians of daily ozone maxima was reduced by 85% in winter, 60% in summer, and 50% in autumn and spring after the meteorological adjustment. For most stations, no significantly negative trends (at the 95% confidence level) of the summer medians of daily O3 or Ox (O3+NO2) maxima were found despite the significant reduction in the precursor emissions in Central Europe. However, significant downward trends in the summer 90th percentiles of daily Ox maxima were observed at 6 sites in the region around Zürich (on average −0.73 ppb yr-1 for those sites). The lower effect of the titration by NO as a consequence of the reduced emissions could partially explain the significantly positive O3 trends in the cold seasons (on average 0.69 ppb yr-1 in winter and 0.58 ppb yr-1 in autumn). The increase of Ox found for most stations in autumn (on average 0.23 ppb yr-1) and winter (on average 0.39 ppb yr-1) could be due to increasing European background ozone levels, in agreement with other studies. The statistical model was also able to explain the very high ozone concentrations in summer 2003, the warmest summer in Switzerland for at least ~150 years. On average, the measured daily ozone maximum was 15 ppb (nearly 29%) higher than in the reference period summer 1992–2002, corresponding to an excess of 5 standard deviations of the summer means of daily ozone maxima in that period.

Precipitation changes and variability in Turkey linked to the North Atlantic oscillation during the period 1930–2000

AbstractRelationships between the variability of the North Atlantic oscillation (NAO) indices and the normalized precipitation at 78 stations in Turkey, and the influences of the extreme NAO index (NAOI) episodes and the year‐to‐year and longer time‐scale variations in the NAO on the precipitation conditions were investigated. The results of the study have led to the following main conclusions and evaluations for Turkey:(i) There is a negative relationship between interannual variability of the Turkish precipitation series and the NAO indices. Negative relationships that are particularly strong in winter and partly in autumn are detected to be weaker in spring and almost non‐existent in summer. Correlation coefficients are significant at 61 stations in winter, whereas they are significant at 23 and eight stations in autumn and spring respectively. (ii) Composite precipitation means corresponding to the extreme NAOI phases mostly exhibit an apparent opposite anomaly pattern, except in summer, between the negative and positive NAOI phases. (iii) Annual, winter, spring, autumn and partly the summer composite precipitation means are mostly characterized by wetter than the long‐term average conditions during the negative NAOI phase, whereas the positive NAOI responses mostly exhibit drier than the long‐term average conditions annually and in all seasons except summer. (iv) Spatially coherent and statistically significant changes in the precipitation amounts during the extreme NAOI phases are more apparent in the west and mid Turkey. (v) Low‐frequency fluctuations in the circulation over the Atlantic have been closely linked to the coherent large‐scale precipitation anomalies that have persisted, particularly in winter, over Turkey since the early 1960s. (vi) There is a great resemblance between the spatial distribution and magnitude of the negative correlation coefficients and the spatial distribution patterns and severity of the wet (dry) conditions with negative (positive) NAOI phase, annually and in the winter and autumn seasons. (vii) The coherent regions characterized with significant correlation coefficients coincide perfectly with the coherent regions characterized by the extreme NAOI signals. These clear associations increase our confidence with the results. Copyright © 2003 Royal Meteorological Society