Impact of different forcing factors on N:P balance in a semi-enclosed bay: The Gulf of Trieste (North Adriatic Sea)

The availability and partition of nitrogen (N) and phosphorus (P) in inorganic and organic compartments, as well as their stoichiometric ratio, are influenced by both physical and biological forcing factors. On this basis, the temporal and spatial dynamics in N:P atomic ratios in different compartments may provide information on the functioning of marine ecosystems. Here we explore the relative importance of water temperature, river inputs, wind mixing, stratification, ingression of nutrient-depleted Eastern Adriatic Current and phytoplankton biomass on concentrations and ratios between nitrogen and phosphorus in a semi-enclosed bay (the Gulf of Trieste), using data from monitoring programs carried out during 8 years. Water samples are first classified in 6 water types based on N:P ratios in different components, and then relationships between water type space-time distribution and a set of forcing factors is sought. Results show that the gulf is characterised by relatively stable N:P ratios in all compartments (about 23-26), always exceeding the classical Redfield ratio. In the surface layer, however, nitrogen and phosphorus dynamics are decoupled because of river input and plankton productivity, and a significant spatial and temporal variability is observed in terms of stoichiometric balance, nutrient concentrations and partition among the different pools. Deviations from stable N:P ratios follow a seasonal evolution. In spring, continental inputs alter inorganic nutrient compartments (N:P up to 115); later on, during the seasonal succession of biological processes (e.g. late spring phytoplankton blooms, summer increase in microbial activities and autumn phytoplankton blooms), a change is also seen in the organic dissolved and particulate pools. Multivariate statistical analysis suggests that, among the considered forcing factors, the most relevant in modulating the N:P stoichiometry in the Gulf of Trieste are river inputs and ingression of the Eastern Adriatic Current (acting in opposite directions) along with phytoplankton dynamics. During the whole period, besides variations in N:P stoichiometry, in the Gulf of Trieste dissolved organic matter represents the largest pool of N and P, which can provide a source of nutrients for the planktonic community alternative to inorganic nutrient.     

Wavelet analysis on transient behaviour of tidal amplitude fluctuations observed by meteor radar in the lower thermosphere above Bulgaria

On the basis of bispectral analysis applied to the hourly data set of neutral wind measured by meteor radar in the MLT region above Bulgaria it was demonstrated that nonlinear processes are frequently and regularly acting in the mesopause region. They contribute significantly to the short-term tidal variability and are apparently responsible for the observed complicated behavior of the tidal characteristics. A Morlet wavelet transform is proposed as a technique for studying nonstationary signals. By simulated data it was revealed that the Morlet wavelet transform is especially convenient for analyzing signals with: (1) a wide range of dominant frequencies which are localized in different time intervals; (2) amplitude and frequency modulated spectral components, and (3) singular, wave-like events, observed in the neutral wind of the MLT region and connected mainly with large-scale disturbances propagated from below. By applying a Morlet wavelet transform to the hourly values of the amplitudes of diurnal and semidiurnal tides the basic oscillations with periods of planetary waves (1.5/20 days), as well as their development in time, are obtained. A cross-wavelet analysis is used to clarify the relation between the tidal and mean neutral wind variability. The results of bispectral analysis indicate which planetary waves participated in the nonlinear coupling with the atmospheric tides, while the results of cross-wavelet analysis outline their time intervals if these interactions are local.     

Seasonalizing mountain system recharge in semi-arid basins-climate change impacts

Climate variability and change impact groundwater resources by altering recharge rates. In semi-arid Basin and Range systems, this impact is likely to be most pronounced in mountain system recharge (MSR), a process which constitutes a significant component of recharge in these basins. Despite its importance, the physical processes that control MSR have not been fully investigated because of limited observations and the complexity of recharge processes in mountainous catchments. As a result, empirical equations, that provide a basin-wide estimate of mean annual recharge using mean annual precipitation, are often used to estimate MSR. Here North American Regional Reanalysis data are used to develop seasonal recharge estimates using ratios of seasonal (winter vs. summer) precipitation to seasonal actual or potential evapotranspiration. These seasonal recharge estimates compared favorably to seasonal MSR estimates using the fraction of winter vs. summer recharge determined from isotopic data in the Upper San Pedro River Basin, Arizona. Development of hydrologically based seasonal ratios enhanced seasonal recharge predictions and notably allows evaluation of MSR response to changes in seasonal precipitation and temperature because of climate variability and change using Global Climate Model (GCM) climate projections. Results show that prospective variability in MSR depends on GCM precipitation predictions and on higher temperature. Lower seasonal MSR rates projected for 2050-2099 are associated with decreases in summer precipitation and increases in winter temperature. Uncertainty in seasonal MSR predictions arises from the potential evapotranspiration estimation method, the GCM downscaling technique and the exclusion of snowmelt processes.     

On the biophilic nature of iodine in seawater

Vertical profiles of concentrations of iodate- and total-iodine have been measured at thirty stations in the Pacific, Atlantic and Antarctic Oceans. The salinity-normalised iodine profiles are indicative of both iodine removal and iodate reduction in the euphotic zone. Thus, surface waters appear to be depleted in iodate-iodine (by 0.03?0.22 μM) but less so in total-iodine (by<0.01?0.06 μM) when compared with the near-constant iodine concentrations (～0.46 μM) at depth. Graphs of specific total-iodine versus specific phosphate fit a linear model well and lie within a narrow envelope for all stations, suggesting a direct coupling of iodine and nutrients during assimilation/regeneration. The I/C atom ratio calculated from these hydrographic data (1.0 × 10^?4) agrees well with contemporary plankton compositions (I/C= 1.4 (±0.8) × 10^?4). Similar graphs involving specific iodate also fit a linear model well. However, their gradients vary from station to station leading to a variability in I/C interconversion ratio, analogous to the variability of Redfield nutrient ratios for coastal waters. This variation is attributed to changes in both productivity and nitrate availability. Pacific deep waters contain anomalously high total-iodine concentrations which may reflect regional differences of I/P ratio in surface waters or else diffusion of iodine from bottom sediments.     

A retrospective analysis of nutrients and phytoplankton productivity in the Mississippi River plume

Long-term patterns in riverine nutrient flux in the lower Mississippi River were examined in relationship to spatial and temporal patterns in surface nutrient concentrations, chlorophyll, and primary productivity in the outflow region in the northern Gulf of Mexico. A retrospective analysis of dissolved inorganic nutrient fluxes based on USGS water quality data and US Army Corps of Engineers discharge data from the 1950s to mid-2004 showed an increase in river-borne dissolved inorganic nitrogen (DIN) flux after 1967. Flux of DIN peaked in the early 1980s and has since fluctuated and shown a general decreasing trend since the early 1990s. Records for total phosphorus (total P) fluxes beginning in mid-1974 exhibited a variable but slight increasing trend up to 2004. The increase in fluxes during the 1970s and into the 1980s can be attributed to increases in both nutrient concentrations and river discharge. DIN concentrations since the 1980s have shown a decreasing trend. Total P concentrations exhibited large fluctuations, with no consistent long-term trend. Dissolved organic nitrogen (DON) concentrations and orthophosphate (Ortho P) peaked in the 1980s, declined relative to DIN and remained relatively low. DIN:Ortho P ratios were consistently well above the Redfield N:P ratio of 16:1. DIN:Total P ratios were variable and lower, fluctuating around the Redfield 16:1 value. Both DIN:Ortho P and DIN:Total P ratios were weakly, but significantly, correlated with river discharge and fluctuations were largely a reflection of higher DIN concentrations during high-discharge events. DIN:Ortho P ratios in surface waters of the outflow region adjacent to the birdfoot delta were higher in spring, consistent with seasonal variation in riverine DIN:Ortho P ratios. The seasonal signal diminished with increasing distance to the west of the delta, indicating a selective removal of DIN or source of Ortho P along the shelf. DIN fluxes and SeaWiFS satellite-derived chlorophyll showed seasonally elevated values during the first half of the year followed by generally lower values in late summer and fall. This seasonal signal diminished from east to west. The observed relationship between DIN flux and chlorophyll was consistent with ship-based observations of a linkage between riverine nutrient inputs and productivity. Long-term trends in river discharge were correlated with the Multivariate ENSO (El Niño Southern Oscillation) Index (MEI) (r=−0.281, p<0.0001), evidence that river discharge was influenced by global climatic trends.     

Satellite-derived variability of the Aegean Sea ecohydrodynamics

Eight years of AVHRR-derived sea surface temperature (SST) and SeaWiFS-derived surface chlorophyll (Chl) data (1998–2005) are used to investigate key processes affecting the spatial and temporal variability of the two parameters in the Aegean Sea. Seasonal mean SST and Chl maps are constructed using daily data to study seasonal dynamics whereas empirical orthogonal function (EOF) and correlational analysis is applied to the 8-day composite SST and Chl anomaly time-series in order to study the variability and co-variability of the two parameters from subseasonal to interannual time-scales. The seasonal mean fields show that Black Sea cold and chlorophyll-rich waters enter through the Dardanelles Strait and they are accumulated in the north-eastern part of the Aegean Sea, steered by the Samothraki anticyclone. Large chlorophyll concentrations are encountered in the hydrological front off the Dardanelles Strait as well as in coastal areas affected by large riverine/anthropogenic nutrient loads. The SST seasonal mean patterns reveal strong cooling that is associated with upwelling along the eastern boundary of the basin during summer due to strong northerly winds, a process which is not present in the surface chlorophyll climatology. The Chl dataset presents much stronger sub-seasonal variability than SST, with large variations in the phase and strength of the phytoplankton seasonal cycles. EOF analysis of the anomaly time-series shows that SST non-seasonal variability is controlled by synoptic weather variations and anomalies in the north–south wind-stress component regulating the summer coastal upwelling regime. Mean SST and Chl patterns, and their associated variations, are not closely linked implying that Black Sea and riverine inputs mainly control the intra-annual and interannual variability of the surface chlorophyll in the Aegean Sea rather than mixing and/or upwelling processes.     

A mid-twentieth century reduction in tropical upwelling inferred from coralline trace element proxies

The Cariaco Basin is an important archive of past climate variability given its response to inter- and extratropical climate forcing and the accumulation of annually laminated sediments within an anoxic water column. This study presents high-resolution surface coral trace element records (Montastrea annularis and Siderastrea siderea) from Isla Tortuga, Venezuela, located within the upwelling center of this region. A two-fold reduction in Cd/Ca ratios (3.5–1.7 nmol/mol) is observed from 1946 to 1952 with no concurrent shift in Ba/Ca ratios. This reduction agrees with the hydrographic distribution of dissolved cadmium and barium and their expected response to upwelling. Significant anthropogenic variability is also observed from Pb/Ca analysis, observing three lead maxima since 1920. Kinetic control of trace element ratios is inferred from an interspecies comparison of Cd/Ca and Ba/Ca ratios (consistent with the Sr/Ca kinetic artifact), but these artifacts are smaller than the environmental signal and do not explain the Cd/Ca transition. The trace element records agree with historical climate data and differ from sedimentary faunal abundance records, suggesting a linear response to North Atlantic extratropical forcing cannot account for the observed historical variability in this region.     

Annual and spatial variations of chemical and physical properties in the Ross Sea surface waters (Antarctica)

Temperature, salinity, meltwater percentage, water column stability, dissolved oxygen and nutrients were measured in seawater samples collected at three fixed depths (0, 20, 100 m) in 104 stations located in three different areas of the Ross Sea (Antarctica), during four Italian Antarctic surveys carried out between 1998 and 2006. Nutrient data were used to quantify the nutrient removal, which appears particularly high in 2006, especially in polynya area. The N:P and Si:N disappearance ratios were studied to estimate the dominant phytoplanktonic community. No significant differences in the nutrient drawdown ratio were observed, in fact the N:P ratio was always below the Redfield standard ratio.     

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

To better understand the mechanisms relating to hydrological regulations of chemical weathering processes and dissolved inorganic carbon (DIC) behaviours, high-frequency sampling campaigns and associated analyses were conducted in the Yu River, South China. Hydrological variability modifies the biogeochemical processes of dissolved solutes, so major ions display different behaviours in response to discharge change. Most ions become diluted with increasing discharge because of the shortened reactive time between rock and water under high-flow conditions. Carbonate weathering is the main source of major ions, which shows strong chemostatic behaviour in response to changes in discharge. Ions from silicate weathering exhibit a significant dilution effect relative to the carbonate-sourced ions. Under high temperatures, the increased soil CO₂ influx from the mineralisation of organic material shifts the negative carbon isotope ratios of DIC (δ¹³C_DIC) during the high-flow season. The δ¹³C_DIC values show a higher sensitivity than DIC contents in response to various hydrological conditions. Results from a modified isotope-mixing model (IsoSource) demonstrate that biological carbon is a dominant source of DIC and plays an important role in temporal carbon dynamics. Furthermore, this study provides insights into chemical weathering processes and carbon dynamics, highlighting the significant influence of hydrological variability to aid understanding of the global carbon cycle.     

The Bay of Bengal — A major nutrient source for the deep Indian Ocean

The distribution of nutrient elements and dissolved oxygen in the deep Indian Ocean suggests that the Bay of Bengal Fan sediment serves as a major nutrient element source and oxygen sink. The distribution of nutrient element excesses and oxygen deficiences away from the fan is consistent with diffusion along isopycnal surfaces with circumpolar deep water acting as a sink for nutrient elements and source for dissolved oxygen. In the course of the entire GEOSECS program only at the Bengal Fan station were nutrient element excesses and oxygen deficiencies (relative to the overlying water column) observed in the benthic mixed layer. The unique aspect of this station is likely the result of very high rates of respiration and particle dissolution coupled with a high stability of the water column overlying the benthic mixed layer.The chemical data show that for each mole of organic carbon oxidized 1.5 moles of CaCO₃ must dissolve and that for each mole of CaCO₃ dissolved about one mole of silica go into solution. The NO₃ and PO₄ excesses are about two thirds those predicted from the Redfield ratios (i.e., O₂ : NO₃ : PO₄ = 135 : 15 : 1).     

Relationship between solar radiation and dimethylsulfide concentrations using in situ data for the pristine region of the southern hemisphere

The biological processes have been proposed as climate variability contributors. Dimethylsulfide (DMS) is the main biogenic sulfur compound in the atmosphere; it is mainly produced by the marine biosphere and plays an important role in the atmospheric sulfur cycle. Currently it is accepted that terrestrial biota not only adapts to environmental conditions but also influences them through regulations of the chemical composition of the atmosphere. In the present study we used a wavelet method to investigate the relationship between DMS, Low cloud cover (LCC), Ultraviolet Radiation A (UVA), Total Solar Irradiance (TSI) and Sea Surface Temperature (SST) in the so called pristine zone of the Southern Hemisphere. We found that the series analyzed have different periodicities which can be associated with large scale climatic phenomena such as El Niño (ENSO) or the Quasi-Biennial Oscillation (QBO), and/or to solar activity. Our results show an intermittent but sustained DMS-SST correlation and a DMSUVA anti correlation; but DMS-TSI and DMS-LCC show nonlinear relationships. The time-span of the series allow us to study only periodicities shorter than 11 years, then we limit our analysis to the possibility that solar radiation influences the Earth climate in periods shorter than the 11-year solar cycle. Our results also suggest a positive feedback interaction between DMS and solar radiation.     

Three approaches to radiocarbon calibration of amino acid racemization in Mulinia lateralis from the Holocene of the Chesapeake Bay,USA

A radiocarbon-calibrated aminochronology, based on the bivalve Mulinia lateralis, is presented for Chesapeake Bay core MD03-2661, a 25 m piston core drilled near Kent Island (38°53.21′N; 76°23.89′W) during the 2003 USGS Marion-Dufresne cruise. Three separate approaches were used to calibrate amino acid racemization (AAR) data for aspartic acid with radiocarbon data. For the first approach, a direct or paired analysis calibration incorporated eight articulated specimens, thereby allowing for the application of AAR and radiocarbon analysis of the same specimen and effectively eliminating both intrashell variability and time averaging as factors in the calibration. A second direct approach relied on valves that were bilaterally split to facilitate both AAR and radiocarbon dating, thus effectively eliminating time averaging effects from this calibration. For the third indirect approach, nine independent radiocarbon dates were combined with 129 Asx D/L ratios from the same core depths to produce an indirect calibration model, from which intershell variability and time averaging could be estimated. Variability in AAR ratios was recognized from a myriad of sources, including analytical error, intrashell variability, inherent variability, time averaging, and contamination. The majority of this variability was controlled for through experimental design or by the application of these three independent calibration approaches. The direct calibration of articulated shells and the indirect calibration yielded virtually identical age models, well within their respective 95% confidence intervals. This study establishes an aminostratigraphic reference section for the Holocene record of the Chesapeake Bay and demonstrates the usefulness of multiple calibration approaches and the potential utility of AAR for future studies of sedimentary processes and chronologies in the bay.     

Zonal features of the formation of water chemistry in small lakes in European Russia

Appreciable observational data were used to reveal zonal features of the formation of the chemical composition of waters in small lakes on the territory of European Russia along a transect from tundra to the arid zone. Inter-zonal variability in the parameters of the chemical composition of waters is determined. Zonal differentiation according to hydrochemical parameters is substantiated. The main differentiating elements of the chemical composition of waters in different natural-climatic zones are distinguished. The contribution of the main natural and anthropogenic factors, determining the present-day processes of water formation is analyzed. Different degrees of the effect of non-zonal factors (including anthropogenic ones) on the formation of the chemical composition of lake waters in the humid and arid zones are demonstrated.     

Analysis of recharge-induced geochemical change in a contaminated aquifer

Recharge events that deliver electron acceptors such as O2, NO3, SO4, and Fe3+ to anaerobic, contaminated aquifers are likely important for natural attenuation processes. However, the specific influence of recharge on (bio)geochemical processes in ground water systems is not well understood. The impact of a moderate-sized recharge event on ground water chemistry was evaluated at a shallow, sandy aquifer contaminated with waste fuels and chlorinated solvents. Multivariate statistical analyses coupled with three-dimensional visualization were used to analyze ground water chemistry data (including redox indicators, major ions, and physical parameters) to reveal associations between chemical parameters and to infer processes within the ground water plume. Factor analysis indicated that dominant chemical associations and their interpreted processes (anaerobic and aerobic microbial processes, mineral precipitation/dissolution, and temperature effects) did not change significantly after the spring recharge event of 2000. However, the relative importance of each of these processes within the plume changed. After the recharge event, the overall importance of aerobic processes increased from the fourth to the second most important factor, representing the variability within the data set. The anaerobic signatures became more complex, suggesting that zones with multiple terminal electron-accepting processes (TEAPs) likely occur in the same water mass. Three-dimensional visualization of well clusters showed that water samples with similar chemical associations occurred in distinct water masses within the aquifer. Water mass distinctions were not based on dominant TEAPs, suggesting that the recharge effects on TEAPs occurred primarily at the interface between infiltrating recharge water and the aquifer.     

Groundwater Quality: Analysis of Its Temporal and Spatial Variability in a Karst Aquifer

This study develops an approach based on hierarchical cluster analysis for investigating the spatial and temporal variation of water quality governing processes. The water quality data used in this study were collected in the karst aquifer of Yucatan, Mexico, the only source of drinking water for a population of nearly two million people. Hierarchical cluster analysis was applied to the quality data of all the sampling periods lumped together. This was motivated by the observation that, if water quality does not vary significantly in time, two samples from the same sampling site will belong to the same cluster. The resulting distribution maps of clusters and box‐plots of the major chemical components reveal the spatial and temporal variability of groundwater quality. Principal component analysis was used to verify the results of cluster analysis and to derive the variables that explained most of the variation of the groundwater quality data. Results of this work increase the knowledge about how precipitation and human contamination impact groundwater quality in Yucatan. Spatial variability of groundwater quality in the study area is caused by: a) seawater intrusion and groundwater rich in sulfates at the west and in the coast, b) water rock interactions and the average annual precipitation at the middle and east zones respectively, and c) human contamination present in two localized zones. Changes in the amount and distribution of precipitation cause temporal variation by diluting groundwater in the aquifer. This approach allows to analyze the variation of groundwater quality controlling processes efficiently and simultaneously.     

Ozone content of the atmosphere. 3. Statistics of extreme values of the total ozone content in the midlatitude atmosphere

The occurrence frequency of extremely large and extremely small values of the total ozone content (TOC) for Irkutsk, Berlin, and Saskatoon midlatitude stations (located near 52°N but in different climatic zones) are calculated based on the daily satellite measurements in the 1978–2005 period. The data for various seasons are presented. The interannual variability and regional differences are demonstrated. The results indicate that the TOC variability is mainly caused by natural atmospheric processes.     

Oxygen isotopic composition of alkaline anorogenic granites as a clue to their origin: the problem of crustal oxygen

The primary isotopic characteristics of alkaline granites are often obscured by secondary processes enhanced by their unusual chemical compositions. This is true for radiogenic as well as for stable isotopes. For example, the ⁸⁷Sr/⁸⁶Sr ratios can vary drastically in closed systems because of very high Rb/Sr ratios and can also be easily modified by direct or indirect interaction with continental crust because of low Sr concentrations. Moreover, the frequent occurrence of the granitic massifs as hypovolcanic complexes increases the probability of interaction with meteoric waters which is a common source of important isotopic variability.The investigation of oxygen isotope systematics in alkaline acidic rocks from various environments shows the¹⁸O content of their quartz to be highly invariable, and the δ¹⁸O values to be close to the mantle range of values. This is due to the resistance of quartz to isotopic exchange, which makes it a good tracer of primary isotopic composition. If we eliminate the quartz δ¹⁸O values for which interaction with meteoric water is well documented (five samples), the total range of variation (seventeen samples) is from 6.0 to 7.3‰ relative to SMOW. The values can easily be accounted for by, and correspond to, equilibrium with mantle-type material in a temperature range of 1200-800°C. If we consider possible effects of fractional crystallization, this temperature range can probably be reduced to its lower limit which is much more likely for rocks of acidic composition.The present oxygen isotope study strongly supports an origin for alkaline anorogenic granites from mantle-dominated sources.     

Entropy-based correlated shrinkage of spatial random processes

This paper proposes a two-stage correlated non-linear shrinkage estimation methodology for spatial random processes. A block hard thresholding design, based on Shannon’s entropy, is formulated in the first stage. The thresholding design is adaptive to each resolution level, because it depends on the empirical distribution function of the mutual information ratios between empirical wavelet blocks and the random variables of interest, at each scale. In the second stage, a global correlated (inter- and intra-scale) shrinkage is applied to approximate the values of interest of the underlying spatial process. Additionally, a simulation study is developed, in the Gaussian context, to analyze the sensitivity, measured by empirical stochastic ordering, of the entropy-based block hard thresholding stage in relation to the parameters characterizing local variability (fractality) and dependence range of the spatial process of interest, the noise level, and the design of the region of interest.     

Investigating the use of spatial discretization of hydrological processes in conceptual rainfall runoff modelling: a case study for the meso‐scale

In this study a simple modelling approach was applied to identify the need for spatial complexity in representing hydrological processes and their variability over different scales. A data set of 18 basins was used, ranging between 8 and 4011 km² in area, located in the Nahe basin (Germany), with daily discharge values for over 30 years. Two different parsimoniously structured models were applied in lumped as well as in spatially distributed according to two distribution classifications: (1) a simple classification based on the lithology expressed in three permeability types and (2) a more complex classification based on seven dominating runoff production processes. The objective of the study was to compare the performances of the models on a local and on a regional scale as well as between the models with a view to identifying the accuracy in capturing the spatial variability of the rainfall‐runoff relationships. It was shown that the presence of a specific basin characteristic or process of the distribution classification was not related with higher model performance; only a larger basin size promoted higher model performance. The results of this study also indicated that the permeability generally contained more useful information on the spatial heterogeneity of the hydrological behaviour of the natural system than did a more detailed classification on dominating runoff generation processes. Although model performance was slightly lower for the model that used permeability as a distribution classification, consistency in its parameter values was found, which was lacking with the more complex distribution classification. The latter distribution classification had a higher flexibility to optimize towards the variability of the runoff, which resulted in higher performance, however, process representation was applied inconsistently. Copyright © 2007 John Wiley & Sons, Ltd.     

Application of a data assimilation method via an ensemble Kalman filter to reactive urea hydrolysis transport modeling

With growing importance of water resources in the world, remediations of anthropogenic contaminations due to reactive solute transport become even more important. A good understanding of reactive rate parameters such as kinetic parameters is the key to accurately predicting reactive solute transport processes and designing corresponding remediation schemes. For modeling reactive solute transport, it is very difficult to estimate chemical reaction rate parameters due to complex processes of chemical reactions and limited available data. To find a method to get the reactive rate parameters for the reactive urea hydrolysis transport modeling and obtain more accurate prediction for the chemical concentrations, we developed a data assimilation method based on an ensemble Kalman filter (EnKF) method to calibrate reactive rate parameters for modeling urea hydrolysis transport in a synthetic one-dimensional column at laboratory scale and to update modeling prediction. We applied a constrained EnKF method to pose constraints to the updated reactive rate parameters and the predicted solute concentrations based on their physical meanings after the data assimilation calibration. From the study results we concluded that we could efficiently improve the chemical reactive rate parameters with the data assimilation method via the EnKF, and at the same time we could improve solute concentration prediction. The more data we assimilated, the more accurate the reactive rate parameters and concentration prediction. The filter divergence problem was also solved in this study.