SPM Concentrations Research Articles

Chemical and Isotopic Characteristics of the Water and Suspended Particulate Materials in the Yangtze River and Their Geological and Environmental Implications

Chemical and Isotopic Characteristics of the Water and Suspended Particulate Materials in the Yangtze River and Their Geological and Environmental Implications

The influence of channel deepening on estuarine turbidity levels and dynamics, as exemplified by the Ems estuary

Active deepening of tidal channels usually results in the alteration of the vertical and the horizontal tide. This may lead to concurrent significant increases in mean suspended matter concentrations (SPM) in coastal plain estuaries, the turbidity maximum (ETM) included. This is exemplified by an extensive analysis of the Ems estuary, a prototypical heavily stressed estuary in the Dutch-German border area. Measurements show that the SPM concentrations in the lower reaches of the estuary have increased an average of 2- to 3-fold between 1954 and 2005, with a 10-fold increase observed in the upper estuary (tidal river). Longitudinal profiles of surface SPM demonstrate that the ETM has moved upstream by up to 25 km and has broadened into a zone 30 km in length which extends into the freshwater tidal river. On an annual scale, variations in freshwater discharge significantly influence the formation and breakdown of the ETM: during low river discharge the ETM approaches equilibrium over 2–3 months, whilst elevated river discharges relocate the ETM downstream over several weeks.An exploratory, semi-analytical model is calibrated to simulate the equilibrium SPM distribution in the upper estuary during five time periods from 1965 to 2005, using archival bathymetric and tidal data. Results suggest that the deepening of tidal channels and a reduction in hydraulic drag have most likely resulted in a landward shift of the SPM trapping location. The measured increase in SPM concentrations and the development of fluid mud around the 1990s likely contributed to reduced mixing and bottom drag, creating a feedback loop that further altered tidal and SPM dynamics. It is argued that the removal of some non-erodible (consolidated) layers in the lower reaches of the estuary has created new internal sediment sources that may be responsible for feeding the observed high SPM concentrations, rather than increased sediment input from the boundaries. All findings are based on and supported by measured short-term seasonal fluctuations, as well as long-term developments of yearly averaged concentrations in the longitudinal SPM distribution.

锦州湾浮游植物群落结构特征及其对环境变化的响应

Phytoplankton plays a vital role in marine ecosystem functioning. It generates roughly 50% of the global primary production,affects the climate process and biogeochemical cycles and sets the upper limits to fishery yield. In addition,due to its fast population responses to water quality and environment stressors,phytoplankton is usually employed as an indicator for assessing eutrophication caused by excess nutrient input and ecosystem health. Jinzhou Bay( 120°55'—121°14'E,40°42'—40°52'N) is a small and shallow semi-enclosed bay in north China with a area of 151. 5 km2 and an averaged depth of3. 5 m. It has a long history of heavy pollution featured by water column eutrophication and heavy metals contamination.Two cruises were carried out during August 2011 and May 2012 respectively to study the spatial distribution and assemblage structure of phytoplankton as well as their ecological responses to the environment changes. Surface water phytoplankton samples were collected at 26 stations and the relevant environmental parameters,i. e. water temperature,salinity,pH,DO,SPM,and nutrient( nitrate,phosphate,silicate) concentrations were measured or sampled simultaneously. The phytoplankton assemblages in Jinzhou Bay were mainly composed by diatom and dinoflagellates groups,and most of them were temperate coastal types. A total of 62 species belong to 4 phylum and 41 genera were identified in the summer andspring cruises. Diatoms were dominant both in species number and cell abundance,with a relatively higher proportion of benthic species. The phytoplankton community structures were significantly different between the two sampling periods. In August 2011,the average cell abundance was 41. 44×103cell /L and the first two dominant species were Thalassiosira spp.and Cerarium furca. In May 2012,the average cell abundance was 13. 80 ×103cell /L and the first two dominant species were Cylindrotheca closterium and Skeletonema costatum. The species diversity was relatively higher in spring( mean 2. 46)than in summer( mean 1. 98). Multivariate ordination techniques were employed to explore the relationships between phytoplankton species and environmental parameters by CANOCO 4. 5. Detrended correspondence analysis( DCA) for the species data showed the maximum gradient length was lower than 3,therefore linear model was applied. Furthermore,the results of redundancy analysis( RDA) indicated that nitrate concentrations and water temperature was the most important influencing factor in summer and spring respectively. Compared with the historic data,the dominant phytoplankton species significantly changed during the last 30 years. Smaller-sized phytoplankton and the species typically found in the eutrophicated environment tended to dominant in Jinzhou Bay. In contrast,the Chaetoceros sp. and Coscinodiscus sp. which were common and important in coastal areas,were both low in species number and cell abundance. This variation trend suggested that the culture eutrophication together with other contaminants might produce certain impacts to the species composition of phytoplankton community in Jinzhou Bay. Systematic and long-term monitoring and study is needed to reveal the ecological responses of phytoplankton assemblage to environment changes and to identify the species capable of indicating the water column eutrophication and heavy metal pollution status of Jinzhou Bay.

Effect of spermine treatment on the functioning of Thellungiella salsuginea antioxidant system

The effect of spermine (Spm) treatment on the content of polyamines (PAs) and activities of antioxidant enzymes in the roots and leaves of Thellungiella salsuginea (Pall.) O.E. Schulz plants grown under optimal conditions were studied. The genes encoding three forms of ascorbate peroxidase (APX; APX1, APX2, and APX4) and genes of key enzymes of proline metabolism (Pro, P5CS1, 1P5CD) were identified, and their expression intensity was measured. Six-day-old plants were treated with Spm (1 and 2 mM) and with the inhibitor of polyamine oxidase (PAO) activity, N,N-(2-hydroxyethyl)hydrazine (HEH, 1 and 2 mM) separately or in combination by adding these compounds to nutrient medium. Roots and leaves responded differently to Spm treatment. In the leaves, the content of PAs reduced due to a decreased in the spermidine (Spd) content, whereas in the roots the total pool of PAs increased due to putrescine (Put) and Spd accumulation. Treatment with Spm activated PAO in the roots but not in the leaves; HEH removed this increase, but the intercellular Spm concentration was not substantially changed. It was suggested that treatment with Spm suppressed the biosynthesis of intracellular Spm and, on the other hand, stimulated the reverse conversion of Spm into Spd and further into Put due to the activation of one of the PAO isoforms. Plant treatment with Spm was not accompanied by a noticeable activation enzymes degrading hydrogen peroxide in the roots: APX, (except of peroxidase II), and catalase. However, the activity of Cu/Zn-SOD doubled and the activity of Mn-SOD reduced. In the leaves, slight activation of peroxidases I and III, the inhibition of Cu/Zn- and Mn-SOD, differential changes in the time-coursed of gene expression of three APX isoforms, and activated gene expression of key enzymes of Pro metabolism were observed. At the same time, the level of MDA did not increase either in the leaves or in the roots. This indicates that treatment of Th. salsuginea plants with Spm under optimal growing conditions did not enhance ROS generation and did not manifest prooxidant properties.

Influence of Temperature, Relative Humidity and Seasonal Variability on Ambient Air Quality in a Coastal Urban Area

The concentration of air pollutants in ambient air is governed by the meteorological parameters such as atmospheric wind speed, wind direction, relative humidity, and temperature. This study analyses the influence of temperature and relative humidity on ambient SO2, NOx, RSPM, and SPM concentrations at North Chennai, a coastal city in India, during monsoon, post-monsoon, summer, and pre-monsoon seasons for 2010-11 using regression analysis. The results of the study show that both SO2 and NOx were negatively correlated in summer (r2=0.25 for SO2 and r2=0.15 for NOx) and moderately and positively correlated (r2=0.32 for SO2 and r2=0.51 for NOx) during post-monsoon season with temperature. RSPM and SPM had positive correlation with temperature in all the seasons except post-monsoon one. These findings indicate that the influence of temperature on gaseous pollutant (SO2 & NOx) is much more effective in summer than other seasons, due to higher temperature range, but in case of particulate, the correlation was found contradictory. The very weak to moderate correlations existing between the temperature and ambient pollutant concentration during all seasons indicate the influence of inconstant thermal variation in the coastal region. Statistically significant negative correlations were found between humidity and particulates (RSPM and SPM) in all the four seasons, but level of correlation was found moderate only during monsoon (r2=0.51 and r2=0.41) in comparison with other three seasons and no significant correlation was found between humidity and SO2, NOx in all the seasons. It is suggested from this study that the influence of humidity is effective on subsiding particulates in the coastal region.

Interactions between polyamines and ethylene during grain filling in wheat grown under water deficit conditions

This study was to test the hypothesis that polyamines (PAs) and ethylene may be involved in mediating the effect of water deficit on grain filling. Two wheat cultivars, drought-tolerant Shannong16 (SN16) and drought-sensitive Jimai22 (JM22), were used and subjected to well-watered and severe water deficit (SD) during grain filling. SD reduced the weight of superior and inferior grains, by 7.38 and 23.54 % in JM22, 13.8 and 2.2 % in SN16, respectively. Higher free-spermidine (Spd) and free-spermine (Spm) concentration and lower free-putrescine (Put) concentration, ethylene evolution rate (EER) and 1-aminocylopropane-1-carboxylic acid (ACC) concentration were found in superior grains than those in inferior ones. Opposite to the variations of Spd and Spm concentration, ACC, Put concentration and EER were significantly increased under SD. The percentage variation of PAs and ACC differed with cultivars and grain types. ACC concentration of superior and inferior grains under SD increased significantly at 21 days post-anthesis, by 90 and 164 % in JM22, 65 and 13.2 % in SN16, respectively. The equivalent value of Put concentration was 1.04 and 7.9 % in JM22, 34.4 and 10.3 % in SN16. Spd concentration of superior grains showed a higher decrease than that of inferior ones in both cultivars, while Spm exhibited an opposite trend between both grain types. These percentage variations were highly consistent with the differed responses of weight of both grain types to SD in JM22 and SN16. Grain filling rate was negatively correlated with EER and ACC concentration, while positively correlated with Spd and Spm concentration as well as the ratio of Spd or Spm to ACC. Exogenous Spd or aminoethoxyvinylglycine (an inhibitor of ethylene synthesis by inhibiting ACC synthesis) obviously reduced ACC concentration and EER and increased Spd and Spm concentration, while exogenous ethephon (an ethylene-releasing agent) or methylglyoxal-bis (an inhibitor of Spd and Spm synthesis) showed the opposite effects. The results suggested that it would be good for wheat to have the physiological traits of higher Spd and Spm, as well as a higher Spd/ACC or Spm/ACC, under SD.

H2O2 Involvement in Polyamine-Induced Cell Death in Tobacco Leaf Discs

The response of tobacco (Nicotiana tabacum L.) wild-type SR1 leaf discs in terms of reactive oxygen species (ROS) formation and cell death occurrence was evaluated after exposure to the polyamines (PAs) putrescine (Put), spermidine (Spd), and spermine (Spm). Although NADPH oxidase-like enzyme activity was inhibited by all PAs at 3 or 21 h of treatment, H2O2 content increased significantly in a time- and concentration-dependent manner, suggesting that H2O2 accumulation was linked to the activity of other ROS-generating enzymes. Polyamine oxidase (PAO) activity, which increased markedly upon application of Spd or Spm, is a prime candidate for the increased H2O2 accumulation. Except for 0.1 mM Put, which maintained guaiacol peroxidase (GPOX) and catalase (CAT) activities at the same level as the control, the other PA treatments decreased CAT, ascorbate peroxidase, and GPOX activities at 21 h, contributing to the H2O2 increase. Esterase activity and Evans blue staining, two cell death parameters, were negatively affected at 3 h of treatment with 1 mM Spd and with both concentrations of Spm, whereas at 21 h there was an increase in cell death with both concentrations of the three PAs, except for 0.1 mM Put, which did not alter those parameters. The expression of the senescence-associated cysteine protease gene CP1 was measured to monitor senescence, a physiological cell death process. Application of all PAs increased the expression of the gene, except for 0.1 mM Put, which decreased its expression at 21 h. This result was in agreement with the prevention of cell death exerted by Put and evidenced by Evans blue staining, esterase activity, and electrolyte release.

Relationships Between Geochemical Parameters (pH, DOC, SPM, EDTA Concentrations) and Trace Metal (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) Concentrations in River Waters of Texas (USA)

Water samples from eight major Texas rivers were collected at different times during 1997–1998 to determine the dissolved and particulate trace metal concentrations, expected to show differences in climate patterns, river discharge and other hydrochemical conditions, and human activities along the different rivers. Specifically, two eastern Texas rivers (Sabine, Neches) lie in a region with high vegetation, flat topography, and high rainfall rates, while four Central Texas rivers (Trinity, Brazos, Colorado, and San Antonio) flow through large population centers. Relatively high dissolved organic carbon (DOC) concentrations in the eastern Texas rivers and lower pH led to higher Fe and Mn concentrations in river waters. The rivers that flow through large population centers showed elevated trace metal (e.g., Cd, Pb, Zn) concentrations partly due to anthropogenically produced organic ligands such as ethylenediaminetetraacetic acid (EDTA) present in these rivers. Trace metal levels were reduced below dams/reservoirs along several Texas rivers. Statistical analysis revealed four major factors (suspended particulate matter [SPM], EDTA, pH, and DOC) that can explain most of the observed variability of trace metal concentrations in these rivers. SPM concentrations directly controlled particulate metal contents. Variation in pH correlated with changes of dissolved Co, Fe, Mn, and Ni, and particulate Mn concentrations, while DOC concentrations were significantly related to dissolved Fe concentrations. Most importantly, it was found that, more than pH, EDTA concentrations exerted a major control on dissolved concentrations of Cd and Zn, and, to a lesser extent, Cu, Ni, and Pb.

Long-term trends in hydrochemistry in the Paraíba do Sul River, southeastern Brazil

Summary The Paraiba do Sul watershed is an important hydrological resource for southeastern Brazil, that has undergone extensive land use changes related to industrial, agricultural and urban activities. Over 11 years, between 1997 and 2007, a long-term study was conducted to evaluate hydrochemical variation in the basin outlet through estimations of annual fluxes and identification of their controlling factors. River water was classified as Na–HCO3, with TDS ranging from 32 to 132 mg L−1. Variation between seasons was found: cations, total alkalinity, electrical conductivity, dissolved oxygen, nitrate and chlorophyll “a” had increased values the during low discharge period, while concentrations of DOC, ammonium, nitrite, phosphate and SPM had increased values during the high discharge period. Chloride, sulfate, silica and pH showed no clear relationship with discharge. These patterns also were correlated with hydrological flow paths originating from different sources. Wavelet decomposition was used to characterize precipitation anomalies largely associated both with long-term climate factors (i.e. ENSO) and short-term climate responses from the two discharge periods that were studied. Distinct responses of fluvial hydrochemistry were observed including ENSO-induced fluctuation to be particularly strong for DOC, with annual flux varying approximately 60% around measured median value.

Variability in the sub-surface light climate at ecohydrodynamically distinct sites in the North Sea

This paper shows that the sub-surface light regime in the offshore North Sea varies spatially and seasonally between different ecohydrodynamic regions, which is likely to have important implications for primary production and carbon and nutrient fluxes in different areas of the North Sea. Measurements of downward irradiance were collected using different instruments (i.e. water column-profiling instruments, semi-autonomous moorings, and remote sensing) at three ecohydrodynamically distinct sites in the North Sea: in the southern Bight (SB), at the Oyster Grounds (OG) and north of the Dogger Bank (ND). The ND site was the deepest, and had the lowest and least variable light attenuation coefficients (mean Kd(PAR) = 0.11 m−1). The onset of the phytoplankton spring bloom was earlier than at the other two sites. In summer, ND had low Kd(PAR) ~ 0.07 m−1 and light penetration was shifted towards blue-green wavelengths (490–560 nm), with water itself being one of the strongest contributors to overall attenuation. In contrast, the SB site was characterised by the highest and most variable values of Kd(PAR) (mean = 0.54 m−1), comparable to near-coastal waters, and the spring bloom started almost a month later than at the ND site. The vertical variability of the attenuation coefficient and the strong PAR attenuation in the blue region of the spectrum were the result of higher concentrations of phytoplankton, CDOM and SPM, due to riverine inputs, shallow depth and strong tidal mixing. The OG site showed intermediate conditions between the ND and SB sites with a mean Kd(PAR) = 0.23 m−1, and deepest penetration of irradiance in the green region of the spectrum at 560 nm. The implications of these results for phytoplankton growth and ecosystem modelling are discussed.

Particulate metal distribution in Tagus estuary (Portugal) during a flood episode

Particulate metal concentrations were assessed before, during and after a flood episode in the Tagus estuary. Particulate metal concentrations showed a decrease during the flood period and very similar values in the months before and after the flood event. Before this period, sampling station characteristics were verified to be homogenous during the peak of the flooding event, as all of the sampling stations assumed very specific characteristics. One of the main consequences from the flood, concurrent with a decrease in particulate metal concentrations, was the high input of SPM into the estuarine area. This finding indicates higher levels of heavy metals in fine-sized particles at low SPM concentration than those present in coarser particles at high SPM levels. These periodic flood events can be considered as estuarine contamination masks and should be interpreted as periods of dilution in heavy metal contamination rather than as an estuarine cleansing process.

Effect of exogenous spermidine on polyamine content and metabolism in tomato exposed to salinity–alkalinity mixed stress

We investigated the effects of seeds pretreatment with exogenous spermidine (Spd) on the polyamine content and metabolism in the roots of two cultivars of tomato (Solanum lycopersicum), Jinpengchaoguan and Zhongza No. 9 grown under conditions of mixed salinity-alkalinity stress. These cultivars differ in their tolerance to salinity stress, with the former more tolerant than the latter. PA content, whether in its free forms, soluble conjugated forms, or insoluble bound forms, increased significantly during salinity-alkalinity stress. The activities of S-adenosylmethionine decarboxylase (SAMDC) and diamine oxidase (DAO), concentrations of free Spd, soluble conjugated forms of Spd and spermine (Spm), and insoluble bound form of Spd in the roots were enhanced to a greater extent in cv. Jinpengchaoguan roots than in cv. Zhongza No.9 in response to salinity-alkalinity stress. Interestingly, Spd application to seeds markedly suppressed the accumulation of free Put, but promoted an increase in free Spd and Spm concentrations, as well as soluble conjugated forms of Spd and insoluble bound forms of Put in both cultivars. From these data, we deduced that exogenous Spd promotes the conversion of free Put into free Spd and Spm, and soluble conjugated forms and insoluble bound forms of PAs under salinity-alkalinity stress. Furthermore, under salinity-alkalinity stress conditions, exogenous Spd enhanced the activities of ODC, SAMDC and DAO, and reduced the activities of ADC and polyamine oxidase (PAO) in cv. Zhongza No.9 roots. In addition, exogenous Spd reduced the activities of ADC and ODC, and increased the activities of DAO and SAMDC in cv. Jinpengchaoguan roots under salinity-alkalinity stress conditions. These results suggest that exogenous Spd treatment can regulate the metabolic status of polyamines caused by salinity-alkalinity stress, and eventually enhance tolerance of tomato plants to salinity-alkalinity stress. Additionally, Spd treatments have varying effects on different tolerant tomato cultivars.

Estimating estuarine turbidity: An application to estuaries of the Isle of Man and northeast Irish Sea

A simple estimation method for estuarine turbidity that may be helpful for management purposes is used to predict SPM concentrations for the strongly tidal estuaries of the northeast Irish Sea. It demonstrates a systematic tendency for the longer, more slowly flushed estuaries to have greater ‘intrinsic’ SPM concentrations within their high turbidity regions than the shorter estuaries. Predicted maximum SPM concentrations for the mainland estuaries vary from ∼10 mg l−1 (Bladnoch) to ∼10 g l−1 (Solway, Mersey and Dee). The Isle of Man estuaries are predicted to have maximum SPM concentrations that are less than 10 mg l−1. These small predicted concentrations are largely a consequence of their short lengths and short residence times. Geomorphology is the ultimate reason for this difference in Isle of Man and mainland estuarine turbidity. The Isle of Man has steep slopes and small rivers that flow rapidly to sea via short estuaries, whereas the mainland has a number of large, long, coastal plain estuaries that allow strong tidal currents to develop and provide storage for large quantities of fine sediment. Survey data for the Solway Esk and the Forth and Clyde Estuaries are used to illustrate the effects of uncertainty in the definition of an estuary's tidal length, which is a problem both for estuarine science and estuarine management. Despite the dearth of published, good quality field data for the estuaries described herein, there is nevertheless a good qualitative agreement between the predicted values of SPM and the majority of these observations.

Origin and composition of particulate organic matter in a macrotidal turbid estuary: The Gironde Estuary, France

At the interface between continent and ocean, estuaries receive particles, and especially particulate organic matter (POM) originating from these two reservoirs, but also produce POM, through autochthonous primary production. The origin and composition of surface POM in the Gironde Estuary (SW France) and the environmental forcing of its variability was investigated using the data set produced by the French Coastal Monitoring Network SOMLIT (Service d'Observation en Milieu LITtoral; monthly like sampling during years 2007–2009). This estuary is considered as a model of macrotidal turbid estuaries. Using elemental and isotopic composition of the POM, we estimated that, at the inner estuary space scale and inter-annual time scale, surface particulate organic carbon (POC) was composed of terrestrial POM originated from the turbidity maximum (96.4%; refractory POC) and flood events (1.6%; labile and refractory POC), and of riverine (0.1%), estuarine (0.8%) and marine (1.1%) phytoplankton, i.e. that POC was 98% and 2% of terrestrial and phytoplankton origin, respectively. However, there was a clear spatial gradient: the phytoplankton contribution increases from ca. 1% in the upper and middle estuary to 8.5% in the lower estuary, where light condition is more favourable to plankton growth. The low contribution of phytoplankton to the POC is a characteristic of the Gironde estuary and contrast with other large temperate estuaries. Statistical analysis indicates that salinity, river flow and SPM concentration, and thus associated hydro-dynamic and sedimentary processes, were the only environmental forcings to the composition of surface POC in this system, at intra- and inter-annual time scale. In contrast, temperature and nutrient concentrations, and thus associated processes, do not force this composition of POC.By combining POC fluxes entering the inner estuary (literature data), POC loss as dissolved organic carbon and CO2 and as sediment trapping within the inner estuary (literature data), and our estimate of the composition of POC flux at the mouth of the estuary (96% and 4% of terrestrial and phytoplankton origin), a first-order net export of POC originating from the Gironde to the continental shelf was estimated: it amounts 48,150tCyr−1, and is composed of 46,200tCyr−1 of terrestrial material and of 1950tCyr−1 of estuarine phytoplankton. POC exported by the Gironde Estuary is thus poorly bioavailable for shelf pelagic and benthic food webs.

Polyamine and ethylene interactions in grain filling of superior and inferior spikelets of rice

This study was to test the hypothesis that polyamines (PAs) and ethylene and their interactions may be involved in mediating the post-anthesis development of spikelets in rice (Oryza sativa L.). Six rice cultivars differing in grain filling rate were field-grown, and the changing patterns of PAs and ethylene levels in rice spikelets during the filling and their relations with grain filling rates were investigated. The results showed that inferior spikelets had much greater ethylene evolution rate and 1-aminocylopropane-1-carboxylic acid (ACC) concentration than superior spikelets. Opposite to ethylene production, superior spikelets showed much higher free-spermidine (Spd) and free-spermine (Spm) concentrations than inferior spikelets. Grain filling rate was very significantly and negatively correlated with ethylene evolution rate and ACC concentration, whereas positively correlated with free-Spd and free-Spm concentrations and with the ratio of free-Spd or free-Spm to ACC. Application of Spd, Spm, or aminoethoxyvinylglycine (an inhibitor of ethylene synthesis by inhibiting ACC synthesis) to panicles at the early grain filling stage significantly reduced ethylene evolution rate and ACC concentration, while significantly increased Spd and Spm concentrations, grain filling rate and grain weight of inferior spikelets. Application of ACC, ethephon (an ethylene-releasing agent), or methylglyoxal-bis (guanylhydrazone) (an inhibitor of Spd and Spm synthesis) showed the opposite effects. The results suggest that antagonistic interactions between PAs (Spd and Spm) and ethylene may be involved in mediating grain filling. A higher ratio of free-Spd or free-Spm to ethylene in rice spikelets could enhance grain filling.

Study on Secondary Inorganic Particle Formation in High Concentrations of SPM in Kawasaki City utilizing Tape Filters

Study on Secondary Inorganic Particle Formation in High Concentrations of SPM in Kawasaki City utilizing Tape Filters

Study on causes of SPM concentration trends in recent years in urban area of the Kanto District based on data at air quality monitoring stations

Study on causes of SPM concentration trends in recent years in urban area of the Kanto District based on data at air quality monitoring stations

Simulation of SPM Concentration Taking into Account the Effect of Liquid Water

Simulation of SPM Concentration Taking into Account the Effect of Liquid Water

Remote sensing reflectance of Pomeranian lakes and the Baltic

The remote sensing reflectance Rrs, concentrations of chlorophyll a and other pigments Ci, suspended particulate matter concentrations CSPM and coloured dissolved organic matter absorption coefficient aCDOM(λ) were measured in the euphotic zones of 15 Pomeranian lakes in 2007–2010. On the basis of 235 sets of data points obtained from simultaneous estimates of these quantities, we classified the lake waters into three types. The first one, with the lowest aCDOM(440nm) (usually between 0.1 and 1.3m−1 and chlorophyll a concentrations 1.3 < Ca < 33mg m−3), displays a broad peak on the reflectance spectrum at 560–580nm and resembles the shape of the remote sensing reflectance spectra usually observed in the Baltic Proper. A set of Rrs spectra from the Baltic Proper is given for comparison. The second lake water type has a very high CDOM absorption coefficient (usually aCDOM(440nm) > 10m−1, up to 17.4m−1 in Lake Pyszne; it has a relatively low reflectance (Rrs < 0.001sr−1) over the entire spectral range, and two visible reflectance spectra peaks at ca 650 and 690–710nm. The third type of lake water represents waters with a lower CDOM absorption coefficient (usually aCDOM (440nm)< 5m−1) and a high chlorophyll a concentration (usually Ca > 4mg m−3, up to 336mg m−3 in Lake Gardno). The remote sensing reflectance spectra in these waters always exhibit three peaks (Rrs > 0.005sr−1): a broad one at 560–580nm, a smaller one at ca 650nm and a well-pronounced one at 690–720nm. These Rrs(λ) peaks correspond to the relatively low absorption of light by the various optically active components of the lake water and the considerable scattering (over the entire spectral range investigated) due to the high SPM concentrations there. The remote sensing maximum at λ ≈ 690–720nm is higher still as a result of the natural fluorescence of chlorophyll a. Empirical relationships between the spectral reflectance band ratios at selected wavelengths and the various optically active components for these lake waters are also established: for example, the chlorophyll a concentration in surface water layer Ca=6.432 e4.556X, where X=[max Rrs(695 ≤ λ ≤ 720) – Rrs(λ=670)]/max Rrs(695 ≤ λ ≤ 720), and the coefficient of determination R2=0.95.

Effects of combustion emissions from the Eurasian continent in winter on seasonal δ13C of elemental carbon in aerosols in Japan

Abstract We investigated suspended particulate matter (SPM, particles with a 100% cut-off aerodynamic diameter of 10 μm) and PM2.5 (particles with a 50% cut-off aerodynamic diameter of 2.5 μm) concentrations in aerosols sampled in Akita Prefecture, Japan, from April 2008 to January 2010, and the carbon isotope ratios (δ 13 C) of elemental carbon (EC) in both SPM and PM2.5 and in samples from possible sources. We also determined the ion contents of SPM and estimated the back trajectories of air masses arriving at Akita Prefecture during the study period. The SPM concentration was very low (annual average, 15.2 μg m −3 ), and it tended to be higher in spring and lower in winter. We attributed the higher SPM in spring to dust storms brought from the Asian continent. The average annual PM2.5 concentration was 8.6 μg m −3 . δ 13 C of source samples (gasoline and diesel vehicle exhaust, fireplace soot, open biomass burning emissions, street dust, soil, charcoal, and coal) ranged from −34.7‰ to −1.8‰. δ 13 C values of soot from gasoline light-duty (−24.4 ± 0.7‰) and passenger vehicles (−24.1 ± 0.6‰) were very similar to that of soot from all diesel vehicles (−24.3 ± 0.3‰). δ 13 C was enriched in SPM in winter compared with summer values, moreover, only a slight seasonal trend was detected in δ 13 C in PM2.5. From these data and the source results, we hypothesized that the enrichment of δ 13 C of SPM and PM2.5 in winter was a long-range effect of overseas combustion processes such as coal combustion. In addition, δ 13 C of SPM was correlated with Cl − and Mg 2+ contents in SPM, suggesting the influence of sea salt. We verified this hypothesis by back trajectory analyses. The results indicated a continental influence effects on EC of SPM and PM2.5 in winter.