基于在线自动监测的钦州湾海域水质参数周年时空变化特征

通过分析位于钦州湾的2个海水水质自动监测站2009-2010年的自动监测数据,发现钦州湾水温、盐度、溶解氧季节变化明显,海水表层水温变化是引起钦州湾溶解氧含量变动的主要原因;钦州湾海水表层盐度及pH值主要受钦江、茅岭江径流及潮汐涨落的影响;处于河口区域,受大陆径流影响显著的海域使用海水水质标准来评价有欠妥当。     

Major ion chemistry and hydrochemical studies of groundwater of parts of Palar river basin, Tamil Nadu, India

Groundwater is almost globally important for human consumption as well as for the support of habitat and for maintaining the quality of base flow to rivers, while its quality assessment is essential to ensure sustainable safe use of the resources for drinking, agricultural, and industrial purposes. In the current study, 50 groundwater samples were collected from parts of Palar river basin to assess water quality and investigate hydrochemical nature by analyzing the major cations (Ca, Mg, Na, K) and anions (HCO(3), Cl, F,SO(4), NO(3), PO(4),CO(3), HCO(3), and F) besides some physical and chemical parameters (pH, electrical conductivity, alkalinity, and total hardness). Also, geographic information system-based groundwater quality mapping in the form of visually communicating contour maps was developed using ArcGIS-9.2 to delineate spatial variation in physicochemical characteristics of groundwater samples. Wilcox classification and US Salinity Laboratory hazard diagram suggests that 52% of the groundwater fall in the field of C2-S1, indicating water of medium salinity and low sodium, which can be used for irrigation in almost all types of soil with little danger of exchangeable sodium. Remaining 48% is falling under C1-SI, indicating water of low salinity and low sodium.     

Surface water quality assessment of the Vatinsky Egan River catchment, West Siberia

Stream water chemistry were analyzed across Vatinsky Egan River Catchment (West Siberia). The objective of the study is to reveal the spatial and seasonal variations of the water quality and to assess the anthropogenic chemical inputs into the river system. Stream chemistry were monitored in 24 sampling sites for a period extended from January 2002 to December 2005. Spatial distribution of constituents in the Vatinsky Egan River basin indicated pollution from non-point sources associated with oil development. Data revealed that ion concentrations of river waters are usually negatively correlated with stream discharge. The major spatial variations of the hydrochemistry are related to the salinity. Chloride exhibited wide and high concentration range. A comparison with another rivers of West Siberia reveals that Vatinsky Egan River is the most saline and regional impacts further out in the watershed. The salinity of the river water increases substantially as it crosses Samotlor oil field. Many Cl(-) concentrations in the middle and lower parts of the catchment exceed the world average river values by one or more orders of magnitude. For 38% of sampling events, total petroleum hydrocarbons (TPH) concentrations were above the recommended water quality standards.     

Seasonal variations of dissolved inorganic nutrients transported to the Linjiang Bay of the Three Gorges Reservoir, China

Field surveys were carried out from January 2007 to December 2008 to investigate seasonal variations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) transported to the Linjiang Bay of the Three Gorges Reservoir, China. The results revealed that both DIN and DIP exhibited large seasonal variability. DIN (dominated by NH₄?CN) concentrations were drastically higher in the dry season than those in the rainy season, and the same seasonal patterns of DIP concentrations and DIN and DIP fluxes were observed but inverse to that of DIN concentrations. The interannual variation in DIN fluxes descended by 28.2% from 2007 to 2008, while DIP fluxes increased by 40.9%, which were closely constant with interannual changes in DIN and DIP concentrations, respectively. The study indicated that nutrient fluxes (DIN and DIP) were strongly correlated with both nutrient concentrations and river discharge, and the Linjiang Bay received approximately 3,416 × 10³ kg DIN and 324 × 10³ kg DIP every year. In addition, DIN mainly originated from point sources, but DIP originated from non-point sources. It is shown that to control point source pollution is the most effective step for water quality improvement and reducing nutrient loading inputs in the Linjiang Bay.     

A study on the behaviour of pesticides and their transformation products in the Scheldt estuary using liquid chromatography-electrospray tandem mass spectrometry

Off-line solid-phase extraction (SPE) combined with liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS-MS) was used to study the estuarine behaviour of the polar pesticides, atrazine, chloridazon, diuron and metolachlor, and their transformation products (TPs), hydroxyatrazine (HA), desisopropylatrazine (DIA), desethylatrazine (DEA), 3,4-dichlorophenylmethylurea (DPMU) and monuron. The compounds were identified by comparing their LC retention times and product-ion spectra with those of standard solutions. In all but one case the detection limits of the method were sufficient to determine the compounds of interest over the entire salinity range in the estuary. The concentrations of the dissolved pesticides ranged from 70 ng l-1 for chloridazon to 1350 ng l-1 for diuron. The levels of TPs were 3-8% of the levels of their parent pesticide. The mixing plots of polar pesticides and their TPs indicated that TPs, which are present in fresh river water, are conservatively transported to the sea and that no additional amounts of TPs are formed during their transport through the estuary. The one exception was HA, of which approximately 10% of the amount transported to the North Sea is formed in the lower part of the estuary by photochemical oxidation of atrazine. The latter was concluded from the ratios of each analyte over the sum total of the parent pesticide and all TPs along the salinity gradient, which proved to be a useful tool for identifying such estuarine transformations.     

Statistical analysis of the physico-chemical data on the coastal waters of Cochin

Measurements of temperature, salinity, dissolved oxygen, nitrogen as ammonia, nitrate and nitrite, and phosphate along with chlorophyll were carried out at three stations on the coastal waters of Cochin, south west India, at two-levels of the water column over a period of five years. The data set has been factorised using principal component analysis (PCA) for extracting linear relationships existing among a set of variables. A graphical display of the scores generated from the PCA was done by means of boxplots and biplots, which helped in the interpretation of the data. The major factors conditioning the system are related to the input of fresh water from the estuary of the Periyar river and the high organic load of the bottom sediment in the coastal area which results in a reducing environment, as reflected in the parameters of dissolved oxygen, ammoniacal-nitrogen and nitrite-nitrogen. Another factor which contributes to the variation in the system is related to the unloading activity in the port area. The present approach presents a logical way to interpret the complex data of the physico-chemical measurements.     

Distribution of iron and manganese in the Seine river estuary: approach with experimental laboratory mixing

The physico-chemical behaviour of iron and manganese has been observed during many surveys covering various hydrodynamic conditions in the Seine river estuary system. The results obtained confirm the non-conservative behaviour of these two metals. Generally, dissolved iron exhibits non-conservative removal and shows a rapid decrease in low salinity; it is moved from fresh waters with high concentrations to saline waters with very low concentrations. This can be attributed to the flocculation processes as confirmed by laboratory experiments. Dissolved manganese versus salinity curves exhibit a peak concentration in the low salinity zone. Laboratory mixing experiments have been undertaken comparing iron and manganese adsorption/desorption from suspended material versus salinity, using a series of water samples collected in the up-river and marine regions in order to assess the importance of particulate material and salinity on iron and manganese distributions. The salinity was controlled by varying the marine to fresh water ratio. The reaction kinetics aspect is developed in more detail for manganese in the last series of remobilization experiments starting from a stock of suspended particles collected in the upstream river site (Caudebec) in mixtures of waters, according to time and salinity. This study has allowed us to show that iron and manganese behaviour in the Seine estuary is strongly influenced: (i) by the high turbidity zone and by the presence of calcium carbonate which could stabilise the Mn(II) form; and (ii) by the increase of salinity, calcium, magnesium and suspended matter concentrations and by complex formation.     

Temporal variability of macrofauna from a disturbed habitat in Zuari estuary, west coast of India

Natural disturbances along with human interference make the tropical estuaries amongst the most disturbed areas globally. In spite of this, information on the seasonal variability of macrofauna from tropical estuaries is few. Temporal variability of macrofaunal community from Mormugao Bay, Zuari estuary, on the west coast of India was examined from 2003 to 2004 at seven stations. Environmental variability was assessed through physicochemical parameters of water and sediment. The changes in macrobenthic community were assessed using abundance, biomass and species diversity indices. The environmental parameters showed a significant seasonal variation influenced by monsoonal changes. The changes in the environmental conditions brought about variation in the macrobenthic community. Macrofaunal abundance, biomass and species diversity were the highest during post-monsoon influenced by recruitment. In monsoon, the macrobenthic community was dominated by polychaetes (92.17%), whereas bivalves dominated during the post-monsoon (57.7%). The macrofauna showed drastic decline during the stable pre-monsoon season, a period when the highest abundance of fauna is observed in the tropical estuary. Therefore, the macrobenthic community in the area did not follow the seasonal trend generally observed in a tropical estuary. Further, the community during pre-monsoon season was dominated by the opportunistic polychaete species indicating a possible influence of harbour activities in structuring the benthic community of the area.     

Climate change drives warming in the Hudson River Estuary, New York (USA)

Estuaries may be subject to warming due to global climate change but few studies have considered the drivers or seasonality of warming empirically. We analyzed temperature trends and rates of temperature change over time for the Hudson River estuary using long-term data, mainly from daily measures taken at the Poughkeepsie Water Treatment Facility. This temperature record is among the longest in the world for a river or estuary. The Hudson River has warmed 0.945 °C since 1946. Many of the warmest years in the record occurred in the last 16 years. A seasonal analysis of trends indicated significant warming for the months of April through August. The warming of the Hudson is primarily related to increasing air temperature. Increasing freshwater discharge into the estuary has not mitigated the warming trend.     

Phosphorous speciation in surface sediments of the Cochin estuary

Sequential chemical extraction using chelating agents were used to study the P dynamics and its bioavailability along the surface sediments of the Cochin estuary (southwest coast of India). Sediments were analyzed for major P species (iron bound P, calcium bound P, acid soluble organic P, alkali soluble organic P and residual organic P), Fe, Ca, total carbon, organic carbon, total nitrogen and total sulfur contents. An abrupt increase in the concentration of dissolved inorganic P with increasing salinity was observed in the study region. Iron-bound P exhibited a distinct seasonal pattern with maximum values in the monsoon season when fresh water condition was prevailed in the estuary. As salinity increased, the percentage of iron-bound P decreased, while that of calcium-bound P and total sedimentary sulfur increased. C/P and N/P ratios were low which indicate that large amounts of organic matter enriched with P tend to accumulate in surface sediments. The high organic P contribution in the sedimentary P pool may indicate high organic matter load with incomplete mineralization, as well as comparatively greater percentage of humic substance and resistant organic compounds. Principal component analysis is employed to find the possible processes influencing the speciation of P in the study region and indicate the following processes: (1) the spatial and seasonal variations of calcium bound P and acid soluble organic P was mainly controlled by sediment texture and organic carbon content, (2) sediment redox conditions control the distribution of iron bound P and (3) the terrigenous input of organic P is a significant processes controlling total P content in surface sediments. The bioavailable P was very high in the surface sediments which on an average accounts for 59 % in the pre-monsoon, 65 % in the monsoon and 53 % in the post-monsoon seasons. The surface sediments act as a potential internal source of P in the Cochin estuary.     

Water quality and dissolved inorganic fluxes of N,P, SO<Subscript>4</Subscript>, and K of a small catchment river in the Southwestern Coast of India

The southwestern coast of India is drained by many small rivers with lengths less than 250 km and catchment areas less than 6,500 km². These rivers are perennial and are also the major drinking water sources in the region. But, the fast pace of urbanization, industrialization, fertilizer intensive agricultural activities and rise in pilgrim tourism in the past four to five decades have imposed marked changes in water quality and solute fluxes of many of these rivers. The problems have aggravated further due to leaching of ionic constituents from the organic-rich (peaty) impervious sub-surface layers that are exposed due to channel incision resulting from indiscriminate instream mining for construction-grade sand and gravel. In this context, an attempt has been made here to evaluate the water quality and the net nutrient flux of one of the important rivers in the southwestern coast of India, the Manimala river which has a length of about 90 km and catchment area of 847 km². The river exhibits seasonal variation in most of the water quality parameters (pH, electrical conductivity, dissolved oxygen, total dissolved solids, Ca, Mg, Na, K, Fe, HCO₃, NO₂-N, NO₃-N, P _\text-inorg_{\rm \text{-}inorg}, P _\text-tot_{\rm \text{-}tot}, chloride, SO₄, and SiO₂). Except for NO₃-N and SiO₂, all the other parameters are generally enriched in non-monsoon (December–May) samples than that of monsoon (June–November). The flux estimation reveals that the Manimala river transports an amount of 2,308 t y^− 1 of dissolved inorganic nitrogen, 87 t y^− 1 dissolved inorganic phosphorus, and 9246 t y^− 1 of SO₄, and 1984 t y^− 1 K into the receiving coastal waters. These together constitute about 23% of the total dissolved fluxes transported by the Manimala river. Based on the study, a set of mitigation measures are also suggested to improve the overall water quality of small catchment rivers of the densely populated tropics in general and the south western coast in particular.     

Spatial and temporal variability of water quality in the coral reefs of Tayrona National Natural Park,Colombian Caribbean

Tayrona National Natural Park (TNNP) is a hotspot of coral reef biodiversity in the Colombian Caribbean, located between the city of Santa Marta (>455,000 inhabitants) and several smaller river mouths (Rio Piedras, Mendihuaca, Guachaca). The region also experiences a strong seasonal variation in physical parameters (temperature, salinity, wind, and water currents) due to alternating dry seasons with coastal upwelling and rainy seasons. However, the spatial and temporal effects on water quality parameters relevant for coral reef functioning have not been investigated. Therefore, inorganic nutrient, chlorophyll a, and particulate organic carbon (POC) concentrations along with biological O₂ demand (BOD), pH, and water clarity directly above local coral reefs (~10 m water depth) were monitored for 25 months in four bays along a distance gradient (12–20 km) to Santa Marta in the southwest and to the first river mouth (17–27 km) in the east. This is by far the most comprehensive coral reefs water quality dataset for the region. Findings revealed that particularly during non-upwelling, chlorophyll a and POC concentrations along with BOD significantly increased with decreasing distance to the rivers in the east, suggesting that the observed spatial water quality decline was triggered by riverine runoff and not by the countercurrent-located Santa Marta. Nitrate, nitrite, and chlorophyll a concentrations significantly increased during upwelling, while pH and water clarity decreased. Generally, water quality in TNNP was close to oligotrophic conditions adequate for coral reef growth during non-upwelling, but exceeded critical threshold values during upwelling and in relation to riverine discharge.     

Water quality observations in the marine aquaculture complex of the Deeba Triangle,Lake Manzala,Egyptian Mediterranean coast

Coastal aquaculture is faced with extreme variation in water quality. The Deeba Triangle on Lake Manzala is the largest marine coastal aquaculture-producing area on the Egyptian Mediterranean. Samples from 16 ponds were taken during four seasons (2014–2015), to investigate the variation of 12 water quality parameters at that region. We tested the hypothesis that there is no spatial or temporal variation in water quality of the fish ponds. Fish ponds were statistically clustered into three groups (p?=?0.0005) coincident with their geographical location. Hypersaline and transparent waters characterized the western ponds; higher dissolved oxygen and higher nutrients characterized the central region. These spatial differences were principally due to variations in salinity and nutrients of the water sources used for irrigation of the ponds and to differences in the aeration management styles. Strong seasonality was seen in water temperature (following air temperature), nutrients, and turbidity (following the seasonal cycles of various water sources from the Lake Manzala and the seasonality of the petrochemical plants effluents close to these ponds). We conclude that municipal effluents significantly affected, spatially and temporally, the quality of the irrigation water used for coastal aquaculture purposes, which consequently might affect fish yield.     

Chemical speciation of inorganic pollutants in river–estuary–sea water systems

Monitoring studies and thermodynamic modeling were used to reveal the changes of inorganic chemical species of some water pollutants (nutrients and trace metals such as Fe, Mn, Zn, Cu, Cd and Pb) inthe river-estuary-sea water system. The case studies were two rivers, Kamchiya and Ropotamo, representing part of the Bulgarian Black Sea water catchment area, and having different flow characteristics. There were no major differences in inorganic chemical species of the two river systems. NO3(-) and NO2(-) chemical species showed no changes along the river-estuary-sea water system. Concerning phosphates six different species were calculated and differences between the three parts of the systems were established. The HPO4(2-) and H2PO4(-) species were found to be dominant in river waters. The H2PO4(-) species quickly decreased at the expense of HPO4(2-) and Ca, Mg and Na phosphate complexes in estuary and seawater. Trace metals showed a great variety of chemical species. Fe(OH)2(+) species prevailed in river waters, and Fe(OH)3(0) species--in sea waters. Me2+ and MeCO3(0) (Me = Cu, Pb) and PbHCO3(+) were dominant in river waters, while Cu(CO3)2(2-) and PbCl(-) species appear also in sea waters. Cd2+ species prevailed in river and estuary waters, and CdCln(2-n) (n = 1-3) species, in seawater. Free Zn2+ species predominated in all systems but downstream their percentage decreased at the expense of Zn phosphates, carbonates,sulfates and chlorides complexes. Only free Mn2+ species were dominant along the systems.     

Monitoring of the physical parameters and evaluation of the chemical composition of river and groundwater in Calabar (Southeastern Nigeria)

A 12-month study was carried to assess the seasonal and tidal effects on the physical parameters of river and groundwater, which constitute the major potable water sources in Calabar (Nigeria). The study also included an evaluation of the chemical composition of the different water bodies and their relationship. The results show that there was a significant seasonal effect on dissolved oxygen (DO) and nitrate in groundwater on one hand, and on temperature, redox potential (Eh), and DO in river water on the other. Also, a significant tidal influence exists on DO in both river-and groundwater. Comparison between groundwater and river water show statistically significant difference in EC, TDS, Eh, DO, Na, Cl and NO(3). The significant differences in EC, TDS, Na and Cl are due to tidal flushing. The difference in Eh is due to geology of the area while, NO(3) is as a result of anthropogenic pollution. The concentrations of ions in the river and groundwater for the different seasons and tidal cycles show an inverse relationship, while the river water is generally more concentrated than the groundwater. Using a binary mixing model, estimates show that the degree of mixing of river water and groundwater is low, with values of between 1.93% and 2.76% respectively, in the western and eastern parts of the study area. The study concludes that tidal flushing, anthropogenic effects and oxygen supply during recharge contribute to the shaping of water chemistry in the area.     

Variations in seasonal phytoplankton assemblages as a response to environmental changes in the surface waters of a hypo saline coastal station along the Bhagirathi�CHooghly estuary

Due to the close proximity of the Bay of Bengal and the freshwater inflow of Bhagirathi-Hooghly, Diamond Harbour appeared as an important coastal station of the Bhagirathi-Hooghly estuary. The spatial and temporal composition and abundance of microphytoplankton species was examined in relation to physical and chemical surface water variables (i.e., salinity, nutrient, and temperature).The primary objective of the study was to observe the variations in phytoplankton species assemblages as a response to environmental variables. Hierarchical cluster analysis and non-metric multidimensional scaling were used to find out distinct seasonal groups based on the composition of phytoplankton. The results indicate that several key environmental factors like temperature, DIN content, and molar ratio of nutrients like DIN-DIP and DIN-DSi influenced seasonal phytoplankton assemblages within the estuary. The distribution of phytoplankton population showed two main groups where the blue-green and green algal populations favored the warmer conditions of summer and monsoon months, whereas the diatom population primarily flourished in the cooler months of autumn and winter.     

Spatio-temporal variation in the hydrochemistry of Tawa River, Central India: effect of natural and anthropogenic factors

Tawa River is the biggest left bank tributary of the Narmada, the largest west-flowing river of the Indian peninsula. Central India enjoys a tropical climate, is highly urbanized, and the river flow is mostly controlled by monsoon; a large part of the population depend on rivers for their livelihood. Spatial and temporal variations in the hydrochemistry of the Tawa River were studied based on seasonal sampling along the course of the river and its tributaries. The study is important because not much data exist on small size rivers and the river processes spell out correctly in smaller basins. The monsoon season accounts for more than 70 % of river water flow. The basin is characterized by silicate lithology; however, water chemistry is controlled by carbonate-rich soils and other weathering products of the silicate rocks, as indicated by the high (Ca?+?Mg)/(Na?+?K) ratios (>3.8). The values of the Na-normalized ratios of Ca²⁺, Mg²⁺, and HCO₃ ^? suggest that both the carbonate and silicate lithology contribute to the hydrochemistry. On average, 42 % of HCO₃ ^? in the Tawa River water is contributed by silicate weathering and 58 % from carbonate lithology. The water remains undersaturated with respect to calcite during the monsoon and post-monsoon seasons and supersaturated during the pre-monsoon season. A significant influence of mining in the basin and other industrial units is observed in water chemical composition.     

Seasonal appearance of Chlorophyceae phytoplankton bloom by river discharge off Paradeep at Orissa Coast in the Bay of Bengal

Characteristics of the monsoonal bloom of phytoplankton at Orissa Coast in the Bay of Bengal were studied through bimonthly observation from April 2001 to December 2002. Three photosynthetic pigments chlorophyll-a (Chl a), chlorophyll-b (Chl b) and carotenoid (Car) were analyzed by absorption spectroscopic method. The seasonal variation of Chl a included phytoplankton bloom in the coastal area during monsoon period. The water column integrated Chl a reached to 68 mg m(-2) at the station-1(St1), and amounted to 20 mg m(-2) at 30 km off the river mouth during August 2001. In contrast the same amount was found at 15 km off the Mahanadi river mouth during August 2002. Salinity during this period varied from 5 psu at the St1 to 27 psu at the edge of the bloom area. The total amount of river discharge in the monsoon period calculated from daily river discharge data reported by Water Resources Department in India was 84 x 10(9) m(3) during 2001 and 20 x 10(9) m(3) during 2002. Both nitrate and phosphate concentrations showed negative quadratic relationship with salinity throughout the observation period. Extrapolated nitrate and phosphate concentration discharge from the Mahanadi river were 10.8 and 4 microg-at l(-1), respectively. Microscopic identification revealed dominance of fluvial Chlorophyceae and diatoms during the monsoon period showing influence of the freshwater discharge.     

Inter-relations between biological and physicochemical factors in a database for a shallow estuarine system

This paper examines data obtained since 1976 in Peel Inlet and the Harvey Estuary, a shallow estuarine system in Western Australia, which has nuisance growths of macroalgae and seasonal blooms of the cyanobacterium (blue-green alga)Nodularia spumigena. Data collected at the same sites at weekly or fortnightly intervals include phytoplankton (chlorophylla), water nutrients (nitrogen and phosphorus), salinity, temperature and light penetration. Seasonally, the biomass of macroalgae has been measured at a number of sites and used to estimate total biomass.The data are characterised by large season-to-season differences, attributable to the seasonality and volume of river flow. The information has been used to relate the magnitude of summer blue-green algal blooms to the winter loading of phosphorus from the surrounding catchment, and the magnitude of macroalgal biomass to light penetration through the water column.     

Earth-tide-induced fluctuations in the salinity of an inland river,New South Wales,Australia: a short-term study

Wybong Creek discharges salts into the agriculturally and industrially important Hunter River in New South Wales, Australia. Abrupt increases in salinity occur periodically in the mid-Wybong Creek catchment. In order to understand the processes which cause these abrupt increases, changes in surface and groundwater were investigated. It is shown that salinity increases can be attributed to highly discrete groundwater discharge directly into the river from below. Hourly electrical conductivity data measured in the river showed regular, diurnal electrical conductivity fluctuations of up to 350 μS cm^?1. These fluctuations could not be attributed to barometric pressure, temperature, or evapotranspiration. Instead, a similar periodicity in surface water electrical conductivity and groundwater height in nearby groundwater wells was found. Fluctuations were of similar periodicity to the orthotides which cause fluctuations in surface water height and are induced by Earth tides. The geology in the mid-catchment area indicates conditions are optimal for Earth tides to impact groundwater. The reporting of orthotidal changes in water chemistry in this article is believed to be the first of its kind in the scientific literature, with the large fluctuations noted having important implications for water monitoring and management in the catchment. Further research investigating Earth-tide-induced phases of groundwater heights will better constrain the relationships between surface water chemistry and groundwater height.