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The mineral waters of "Guber" Srebrenica are highly mineralized waters with a significant content of soluble iron. They belong to iron-sulfate waters, which are rich in arsenic and therefore also called iron-arsenic waters with low pH values. Some of the "Guber" waters of Srebrenica were used for therapeutic purposes in the past. Spectrophotometric methods were used for their characterization. Today, instrumental methods are known which are faster and more efficient. This work focusses on using the Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) for the characterization of Guber Srebrenica mineral waters. Two standards were used to determine the elemental composition of these mineral waters, which differ in concentration and number of elements present. The results obtained by this method for soluble iron from different sources were compared with the spectrophotometric method of iron determination. The obtained results show that the lower iron concentrations in the samples obtained by the ICP method coincide with the results of the spectrophotometric method. However, with higher concentrations of iron (Očna voda), the deviations of the ICP method from the standard spectrophotometric method are greater and this may be the subject of further research. There are also discrepancies in the results between the standards for lead and arsenic, with higher values occurring in the samples where standards with a smaller number of present elements were used, which necessitates the use of standard methods. [ABSTRACT FROM AUTHOR]

Anthropogenic emission is an important component of the present‐day iron cycle yet its long‐term impacts on climate are poorly understood. Iron mineralogy strongly affects its radiative and oceanic interactions and was unrepresented in previous studies. We perform simulations using a mineralogy‐based inventory and an atmospheric transport model and estimate the 1850–2010 global mean direct radiative forcing (DRF) to be +0.02 to +0.10 W/m2. We estimate that the CO2 sequestration of 0.2–13 ppmv over the last 150 years due to enhanced phytoplankton productivity by anthropogenic iron deposition causes an avoided CO2 forcing of −0.002 to −0.16 W/m2. While globally small, these impacts can be higher in specific regions; the anthropogenic DRF is +0.5 W/m2 over areas with more coal combustion and metal smelting, and anthropogenic soluble iron sustains >10% of marine net primary productivity in the high‐latitude North Pacific Ocean, a region vulnerable to stratification due to climate change. Plain Language Summary: This study examines the question of whether iron released into the atmosphere from human activities could be important in the Earth system. Iron is released from burning fuels, such as coal and oil, and from processing metal ores. The emitted particles contain iron, among other chemical species. This iron absorbs incoming sunlight and warms the atmosphere while it is suspended in the air. Iron is also an essential nutrient for phytoplankton and can enhance their growth when it falls in ocean areas where it is lacking. These stimulated phytoplankton then draw more carbon dioxide from the atmosphere. We evaluate the influence of these two mechanisms on Earth's heat balance (radiative forcing) since pre‐industrial times and include sensitivity studies to examine the highest possible contribution. We find that even with the upper bounds, the global average forcing is much smaller than the total effects of human emissions of species such as carbon dioxide and black carbon. However, in regions with more coal‐burning and smelting, iron aerosol causes noticeable warming and after deposition may be responsible for more than 10% of phytoplankton growth in the higher‐latitude North Pacific Ocean. Key Points: Direct radiative forcing and net primary productivity impacts of anthropogenic iron emissions over the 1850–2010 period are estimatedBoth the effects are globally small but higher over specific regionsAnthropogenic iron is estimated to sustain about 10% of marine productivity in the iron‐limited North Pacific Ocean [ABSTRACT FROM AUTHOR]

Abstract The sustainable food valorization is capable to stimulate the local products consumption with quality and nutritional security. In this scenario, Unconventional Food Plants (UFPs) deserve attention representing an alternative for rural communities and contributing to the local and regional economy. This work aimed to add nutritional information, once it evaluates total Fe concentration, Fe-species (water soluble, acid soluble, and inorganic), proteins, and Fe- proteins distribution in beldroega (Portulaca oleracea L.), guasca (Galinsoga parviflora Cav.), ora-pro-nóbis (Pereskia aculeata Mill.), piracá (Vernonia scorpioides (Lam.) Pers.), and trapoeraba (Commelina benghalensis L.). Considering the Fe total concentration, the studied UPFs can be excellent Fe sources, when compared to foods of plant origin widely consumed and cultivated, detaching the guasca leaves (687±19 µg g-1). However, the guasca leaves showed low concentration of Fe associated to macromolecules and Fe soluble species (1.6±0.3 µg g-1). These results may justify the low bioavailability of Fe species. On the other hand, beldroega leaves presented the highest concentration of inorganic Fe (1.3±0.2 µg g-1). In the UFPs, there is high glutelins concentration when compared to the other protein groups, meaning that UFPs can be low-cost alternative to supplementing protein intake. Finally, for majority UFPs, except guasca leaves, Fe is mainly associated to albumins, being a good source of bioavailable Fe species.

Fossil-fuel emissions may impact phytoplankton primary productivity and carbon cycling by supplying bioavailable Fe to remote areas of the ocean via atmospheric aerosols. However, this pathway has not been confirmed by field observations of anthropogenic Fe in seawater. Here we present high-resolution trace-metal concentrations across the North Pacific Ocean (158°W from 25°to 42°N). A dissolved Fe maximum was observed around 35°N, coincident with high dissolved Pb and Pb isotope ratios matching Asian industrial sources and confirming recent aerosol deposition. Ironstable isotopes reveal in situ evidence of anthropogenic Fe in seawater, with low d56Fe (-0.23? > δ56Fe > -0.65?) observed in the region that is most influenced by aerosol deposition. An isotope mass balance suggests that anthropogenic Fe contributes 21-59% of dissolved Fe measured between 35° and 40°N. Thus, anthropogenic aerosol Fe is likely to be an important Fe source to the North Pacific Ocean. [ABSTRACT FROM AUTHOR]

Previous studies on sporadic amyotrophic lateral sclerosis (SALS) demonstrated iron accumulation in the spinal cord and increased glutamate concentration in the cerebrospinal fluid. To clarify the relationship between the two phenomena, we first performed quantitative and morphological analyses of substances related to iron and glutamate metabolism using spinal cords obtained at autopsy from 12 SALS patients and 12 age‐matched control subjects. Soluble iron content determined by the Ferrozine method as well as ferritin (Ft) and glutaminase C (GLS‐C) expression levels on Western blots were significantly higher in the SALS group than in the control group, while ferroportin (FPN) levels on Western blots were significantly reduced in the SALS group as compared to the control group. There was no significant difference in aconitase 1 (ACO1) and tumor necrosis factor‐alpha (TNFα)‐converting enzyme (TACE) levels on Western blots between the two groups. Immunohistochemically, Ft, ACO1, TACE, TNFα, and GLS‐C were proven to be selectively expressed in microglia. Immunoreactivities for FPN and hepcidin were localized in neuronal and glial cells. Based on these observations, it is predicted that soluble iron may stimulate microglial glutamate release. To address this issue, cell culture experiments were carried out on a microglial cell line (BV‐2). Treatment of BV‐2 cells with ferric ammonium citrate (FAC) brought about significant increases in intracellular soluble iron and Ft expression levels and conditioned medium glutamate and TNFα concentrations. Glutamate concentration was also significantly increased in conditioned media of TNFα‐treated BV‐2 cells. While the FAC‐driven increases in glutamate and TNFα release were completely canceled by pretreatment with ACO1 and TACE inhibitors, respectively, the TNFα‐driven increase in glutamate release was completely canceled by GLS‐C inhibitor pretreatment. Moreover, treatment of BV‐2 cells with hepcidin resulted in a significant reduction in FPN expression levels on Western blots of the intracellular total protein extracts. The present results provide in vivo and in vitro evidence that microglial glutamate release in SALS spinal cords is enhanced by intracellular soluble iron accumulation‐induced activation of ACO1 and TACE and by increased extracellular TNFα‐stimulated GLS‐C upregulation, and suggest a positive feedback mechanism to maintain increased intracellular soluble iron levels, involving TNFα, hepcidin, and FPN. [ABSTRACT FROM AUTHOR]

Wildfire can influence climate directly and indirectly, but little is known about the relationships between wildfire and climate during the Quaternary, especially howwildfire patterns varied over glacial- interglacial cycles. Here, we present a high-resolution soot record from the Chinese Loess Plateau; this is a record of large-scale, highintensity fires over the past 2.6 My. We observed a unique and distinct glacial-interglacial cyclicity of soot over the entire Quaternary Period synchronous with marine δ18O and dust records, which suggests that ice-volume-modulated aridity controlled wildfire occurrences, soot production, and dust fluxes in central Asia. The highintensity fires were also found to be anticorrelated with global atmospheric CO2 records over the past eight glacial-interglacial cycles, implying a possible connection between the fires, dust, and climate mediated through the iron cycle. The significance of this hypothetical connection remains to be determined, but the relationships revealed in this study hint at the potential importance of wildfire for the global climate system. [ABSTRACT FROM AUTHOR]

We present results from transient sensitivity studies with the Biogeochemical Elemental Cycling (BEC) ocean model to increasing anthropogenic atmospheric inorganic nitrogen (N) and soluble iron (Fe) deposition over the industrial era. Elevated N deposition results from fossil fuel combustion and agriculture, and elevated soluble Fe deposition results from increased atmospheric processing in the presence of anthropogenic pollutants and soluble Fe from combustion sources. Simulations with increasing Fe and increasing Fe and N inputs raised simulated marine nitrogen fixation, with the majority of the increase in the subtropical North and South Pacific, and raised primary production and export in the high-nutrient low-chlorophyll (HNLC) regions. Increasing N inputs alone elevated small phytoplankton and diatom production, resulting in increased phosphorus (P) and Fe limitation for diazotrophs, hence reducing nitrogen fixation (∼6%). Globally, the simulated primary production, sinking particulate organic carbon (POC) export. and atmospheric CO2 uptake were highest under combined increase in Fe and N inputs compared to preindustrial control. Our results suggest that increasing combustion iron sources and aerosol Fe solubility along with atmospheric anthropogenic nitrogen deposition are perturbing marine biogeochemical cycling and could partially explain the observed trend toward increased P limitation at station ALOHA in the subtropical North Pacific. Excess inorganic nitrogen ([NO3 −] + [NH4 +] − 16[PO4 3−]) distributions may offer useful insights for understanding changing ocean circulation and biogeochemistry.

The activation of peroxymonosulfate by iron (II), iron (III), and iron (III)–EDTA for in situ chemical oxidation (ISCO) was compared using nitrobenzene as a hydroxyl radical probe, anisole as a hydroxyl radical + sulfate radical probe, and hexachloroethane as a reductant + nucleophile probe. In addition, activated peroxymonosulfate was investigated for the treatment of the model groundwater contaminants perchloroethylene (PCE) and trichloroethylene (TCE). The relative activities of hydroxyl radical and sulfate radical in the degradation of the probe compounds and PCE and TCE were isolated using the radical scavengers tert -butanol and isopropanol. Iron (II), iron (III), and iron (III)–EDTA effectively activated peroxymonosulfate to generate hydroxyl radical and sulfate radical, but only a minimal flux of reductants or nucleophiles. Iron (III)–EDTA was a more effective activator than iron (II) and iron (III), and also provided a non-hydroxyl radical, non-sulfate radical degradation pathway. The contribution of sulfate radical relative to hydroxyl radical followed the order of anisole > > TCE > PCE > > nitrobenzene; i.e., sulfate radical was less dominant in the oxidation of more oxidized target compounds. Sulfate radical is often assumed to be the primary oxidant in activated peroxymonosulfate and persulfate systems, but the results of this research demonstrate that the reactivity of sulfate radical with the target compound must be considered before drawing such a conclusion. [ABSTRACT FROM AUTHOR]

The atmospheric supply of mineral dust iron (Fe) plays a crucial role in the Earth’s biogeochemical cycle and is of specific importance as a micronutrient in the marine environment. Observations show several orders of magnitude variability in the fractional solubility of Fe in mineral dust aerosols, making it hard to assess the role of mineral dust in the global ocean biogeochemical Fe cycle. In this study we compare the operational solubility of mineral dust aerosol Fe associated with the flow-through leaching protocol to the results of the global 3-D chemical transport model GEOS-Chem. According to the protocol, aerosol Fe is defined as soluble by first deionized water leaching of mineral dust through a 0.45 μm pore size membrane followed by acidification and storage of the leachate over a long period of time prior to analysis. To estimate the uncertainty in soluble Fe results introduced by the flow-through leaching protocol, we prescribe an average 50% (range of 30–70%) fractional solubility to sub-0.45 μm sized mineral dust particles that may inadvertently pass the filter and end up in the acidified (at pH ∼ 1.7) leachate for a couple of month period. In the model, the fractional solubility of Fe is either explicitly calculated using a complex mineral aerosol Fe dissolution equations, or prescribed to be 1% and 4% often used by global ocean biogeochemical Fe cycle models to reproduce the broad characteristics of the presently observed ocean dissolved iron distribution. Calculations show that the fractional solubility of Fe derived through the flow-through leaching is higher compared to the model results. The largest differences (∼40%) are predicted to occur farther away from the dust source regions, over the areas where sub-0.45 μm sized mineral dust particles contribute a larger fraction of the total mineral dust mass. This study suggests that different methods used in soluble Fe measurements and inconsistences in the operational definition of filterable Fe in marine environment and soluble Fe in atmospheric aerosols are likely to contribute to the wide range of fractional solubility of aerosol Fe reported in the literature. [ABSTRACT FROM AUTHOR]

In many parts of the global ocean, iron bioavailability is a critical factor controlling primary productivity. Because colloidal Fe (cFe) makes up a substantial proportion of the surface water Fe inventory, it is critical to evaluate the biogeochemical behaviour and availability of this quantitatively important Fe pool. Here we present and review a compilation of over 1300 soluble and corresponding dissolved Fe concentration measurements from which operationally-defined colloidal Fe data have been determined. Partitioning between cFe and the smaller soluble Fe (sFe) size fraction shows a high degree of variability in the surface ocean caused by the range of factors affecting size fractionation (e.g., Fe sources, ligand controls, thermodynamic controls, biological utilisation). Evaluation of the seasonality of sFe and cFe partitioning indicates that a strong decoupling between their respective biogeochemical cycling occurs in the spring time. This suggests that a seasonal component (e.g., seasonal biological growth, seasonal changes in Fe supply) is responsible for a proportion of the observed surface ocean variability. Below depths of 200 m, the partitioning becomes more constant (49 ± 17%). To better understand the bioavailability of the cFe pool, future work should complement traditional size-fractionated data with molecular level investigation into the functional group chemistry of organic Fe colloids and the mineralogy and surface chemistry of inorganic Fe colloids. [ABSTRACT FROM AUTHOR]

This study applied a regional air quality model, incorporated with an emission module, to quantitatively differentiate the atmospheric iron sources originating from lithogenic dusts or coal-burning fly ashes deposited in the Northwestern Pacific Ocean and its marginal seas. Particular attention was paid to the high iron content of fly ashes emitted from steel and iron plants burning coals. Using the year 2007 as an example, the modeling results exhibit large seasonal variations in iron deposition, with highest deposition fluxes occurred during spring and autumn, which are comparable to the seasonal fluctuation of chlorophyll a concentrations estimated by satellite images in the oceanic regions. Fly ash from coal burning accounted for 7.2% of the total iron deposited over the northwestern Pacific Ocean and 15% of that over the northern South China Sea. After considering the difference of iron solubility in the aerosols, anthropogenic aerosol associated with coal burning would be the major bioavailable iron source in the surface water of the oceanic regions. [ABSTRACT FROM AUTHOR]

The air–sea deposition of nutrients (N, P and Fe) to the oceanic regions located downwind of pollution sources in south and south-east Asia is gaining considerable attention in the present-day scenario of climate change. We report here a case study on the atmospheric outflow of nutrients from the Indo-Gangetic Plain (IGP) to the Bay of Bengal (BoB). Air mass back trajectories suggest conspicuous downwind transport of chemical constituents from the IGP to the BoB during the late NE-monsoon (January–April); thus, representing BoB as one of the unique oceanic regions influenced by anthropogenic sources over a short span of 3–4 months. During the course of this study (November'09–March'10), nutrient (NO 3 − , NH 4 + , N Org , PO 4 3 − and Fe ws ) concentrations in the atmospheric outflow show pronounced temporal variability. The inorganic nitrogen (NH 4 + -N: ~ 90% of N Inorg ) dominates the total soluble nitrogen (N Tot ). Although the contribution of organic nitrogen is not significant, the mass ratio of N Org /N Tot in the outflow varied from 0.07 to 0.40. The abundances of P Inorg and Fe ws varied from 0.4 to 4.8 nmol m − 3 and 0.2 to 0.6 nmol m − 3 , respectively. The high abundance of K + and significant (P-value < 0.05) correlation with P Inorg and Fe ws suggest their significant contribution from biomass burning emissions (BBEs). The characteristic mass ratios of nutrients (N Inorg /N Tot : 0.92 ± 0.13 , N Org /N Tot : 0.21 ± 0.11, and P Inorg /nss-Ca 2 + : 0.35 ± 0.23) in the IGP-outflow show striking similarity with those reported over the BoB. These results have implications to further increase in the atmospheric deposition of nutrients and their impact on biogeochemistry of surface Bay of Bengal. [ABSTRACT FROM AUTHOR]

Satellite images showed that two large dust storms swept over the Yellow Sea from 31 Mach to 1 April 2007; both were accompanied by precipitation. Three to four days after the dust episodes, blooms occurred in the Yellow Sea. As an important and potential controlling factor of the bloom, nutrients in the total suspended particle (TSP) and size-segregated particle samples during the cruise campaign were measured and their atmospheric deposition fluxes of nutrients are reported in this paper. Concentrations of total P and TIN (NH4 +, NO2 − and NO3 −) in TSP varied from 0.01 to 1.05μgm−3, and from 1.21 to 22.28μgm−3, with the maximum occurring concurrently with the dust storm events. In addition, the measured solubility of Fe in these particles varied from 1.0 to 20.1%, while it ranged from 0.8 to 15% for Al. The total deposition fluxes of Asian dust as well as the contained nutrients were estimated on the basis of an episodic increment of the measured concentration of dissolved Al in the surface ocean during the dust events. The estimated fluxes of atmospheric deposition of soluble Fe, P and inorganic nitrogen over the Yellow Sea during the dust episodes were 42.5±10.9, 10.3±2.6 and 772.0±198.0mgm−2, respectively. The estimated fluxes of nutrients via dry atmospheric deposition accounted for only ~2% of the total fluxes. The deposition fluxes of particulate Fe and P during the two dust storm events associated with precipitation were about 500–1000 times of that daily averaged flux during non-dust days, indicating the importance of the episodic inputs to the annual budget of these metals deposited into the ocean. [ABSTRACT FROM AUTHOR]

The ash composition is used to assess the conditions of coal-bed formation in the Donets and L'vovsk-Volynsk basins. The experimental data are inconsistent with some aspects of the hypothesis that pyrite and secondary organic sulfur are formed in the coal. The lack of a relationship between the total sulfur content S in the coal and the MgO content in its ash does not agree with the notion that sulfates from sea water provide the basis source of nonvegetative sulfur in coal. The actual S values do not always correspond to the theory that the source of sulfur depends on the alkalinity of the water and the reducing medium where the deposits accumulate. In the conditions that are most favorable to the formation of coal with high total sulfur content (S > 4 wt %) according to the existing hypothesis, the actual value of S is no more than 1.5%. The source of pyrite and organic sulfur in coal requires further discussion. [ABSTRACT FROM AUTHOR]

Abstract: Iron is an essential nutrient for phytoplankton. Although iron-containing dust mobilized from arid regions supplies the majority of the iron to the oceans, the key flux in terms of the biogeochemical response to atmospheric deposition is the amount of soluble or bioavailable iron. Atmospheric processing of mineral aerosols by anthropogenic pollutants (e.g. sulfuric acid) may transform insoluble iron into soluble forms. Previous studies have suggested higher iron solubility in smaller particles, as they are subject to more thorough atmospheric processing due to a longer residence time than coarse particles. On the other hand, the specific mineralogy of iron in dust may also influence the particulate iron solubility in size. Compared to mineral dust aerosols, iron from combustion sources could be more soluble, and found more frequently in smaller particles. Internal mixing of alkaline dust with iron-containing minerals could significantly reduce iron dissolution in large dust aerosols due to the buffering effect, which may, in contrast, yield higher solubility in smaller particles externally mixed with alkaline dust (Ito and Feng, 2010). Here, we extend the modeling study of Ito and Feng (2010) to investigate atmospheric processing of mineral aerosols from African dust. In contrast to Asian dust, we used a slower dissolution rate for African dust in the fine mode. We compare simulated fractional iron solubility with observations. The inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during long-range transport to the Atlantic Ocean: only a small fraction of iron (<0.2%) dissolves from illite in coarsemode dust aerosols with 0.45% soluble iron initially. In contrast, a significant fraction (1–1.5%) dissolves in fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model generally reproduces higher iron solubility in smaller particles as suggested by measurements over the Atlantic Ocean. Our results imply that the dissolution of iron in African dust is generally slower than that in Asian dust. Conventionally, dust is assumed as the major supply of bioavailable iron with a constant solubility at 1–2% to the remote ocean. Therefore, the timing and location of the atmospheric iron input to the ocean with detailed modeling of atmospheric processing could be different from those previously assumed. Past and future changes in aerosol supply of bioavailable iron might play a greater role in the nutrient supply for phytoplankton production in the upper ocean, as global warming has been predicted to intensify stratification and reduce vertical mixing from the deep ocean. Thus the feedback of climate change through ocean uptake of carbon dioxide as well as via aerosol-cloud interaction might be modified by the inclusion of iron chemistry in the atmosphere. [Copyright &y& Elsevier]

Abstract: The solubility of iron (Fe) in atmospheric particulate matter (PM) is important to understand its chemistry and potential bioavailability to ocean phytoplankton. However, current studies on Fe solubility and its speciation are highly uncertain partly due to inconsistencies in analytical protocols. In this study, cloud-processing of atmospheric PM was simulated in acetate, formate, and oxalate buffers (pH=4.30±0.05) at 0.5, 1, 5, and 20mM. Colorimetric analysis of Fe(II)–ferrozine complex showed that Fe solubility increased by an order of magnitude when acetate and formate concentrations increased from 0.5mM to 5mM, with a higher fraction of soluble Fe in acetate than in formate at lower buffer concentration (0.5mM). Measured pH of sample extracts revealed that weak buffers are unable to maintain pH, presumably due to acidic or alkaline components of PM, requiring an optimum concentration (5mM in this study) of acetate and formate for Fe solubility measurements. Similar extraction procedures revealed that oxalate buffer inhibits the formation of Fe(II)–ferrozine complex, especially with Fe(III)-containing solutions, rendering it unsuitable for Fe solubility measurements by Ferrozine method. Application of the optimized analytical method to PM samples from different environments showed quite variable Fe solubility, with the lowest (<1%) in dust-impacted samples and the highest (5%) in urban samples. The highest solubility (6.8%) was observed in ambient PM2.5 samples influenced by anthropogenic sources (car emissions) with more than 90% of soluble Fe in the form of Fe(II). Results from this study highlight the importance of the type and strength of buffer at a given pH for Fe solubility and provide further evidence of a higher Fe solubility in urban PM samples compared to desert dust. [Copyright &y& Elsevier]

Abstract: Experiments were conducted using a semi-continuous batch protocol to leach iron from aerosol samples. In this procedure, aerosol samples were leached in an all-Teflon flow-through reaction chamber by multiple (3–4) aliquots (~40 mL) of leaching solution per predetermined leaching period. Several types of aerosols and leaching solutions were tested. The percent iron solubility obtained from aerosols collected in two urban regions was lower (~1%) than the solubility from samples collected in the open ocean (6–13%). This regional variability was greater than the variability obtained when leaching the same aerosols using different leaching solutions. A review of field and laboratory studies from the literature also suggests that different types of aerosols produce more variability in aerosol iron solubility estimates than do different leaching protocols. Colloidal iron was the dominant fraction of aerosol derived dissolved iron in all the experiments carried out during this study, suggesting that the dissolution of aerosol iron in seawater is dominated by the colloidal iron fraction. [Copyright &y& Elsevier]

In higher plants, it is well known that the retranslocation of iron from old leaves to young leaves is difficult; as a result, iron deficiency leads to interveinal chlorosis, particularly in the young leaves. However, in the case of barley, young chlorotic leaves can grow under conditions of long-term iron deficiency. Previously, we have reported that the distribution and retranslocation characteristics of iron in barley may be better adapted to iron deficiency than those in rice. Furthermore, barley maintained a relatively high chlorophyll index (SPAD value) even when its iron content was not higher than that of rice. In this study, we aimed to predict the chemical form of iron that contributes to the physiologically available iron in barley leaves. To examine the correlation between plant growth and the SPAD value with the amount of fractionated iron, we cultured plant materials in a culture solution containing various iron concentrations. We compared these correlations among barley, rice and sorghum and among three barley cultivars. To compensate for the amount of mugineic acid phytosiderophores (MAs) in the culture solution, we cultured different plant species in the same container. The results revealed that the amount of soluble iron associated with the high-molecular-weight substances (MW >10,000) correlated with the SPAD value of the young barley leaves and the R2 value (determination coefficient) of barley was higher than the values of rice and sorghum. [ABSTRACT FROM AUTHOR]

To observe changes in the concentrations of size- fractionated iron and related environmental factors, experiments were conducted in the northeastern part of the shallow eutrophic lake Dianchi (China) from March 2003 to February 2004. lion concentrations were measured for three size fractions: particulate iron (φ >0.22 μm), colloidal iron (φ = 0.025-0.22 μm) and soluble iron (φ < 0.025 μm), and environmental factors (physicochemical and biological factors) were synchronously analyzed. Results showed that size-fractionated iron and the related environmental factors all varied with season. Colloidal iron accounted for only 5-9% of total iron, while particulate and soluble iron each accounted for 40-50% of total iron. The results suggested that size-fractionated iron can transform into each other, especially the highly reactive colloidal iron. Significant linear correlations were found between iron in different size fractions, and significant correlations were also obtained between chlorophyll a and environmental factors, such as TN, TP and secchi depth. No significant correlation between iron and chlorophyll a was found in this study. [ABSTRACT FROM AUTHOR]

Summary Iron levels were lower in semitendinosus muscle of beef and lamb than in longissimus or triceps brachii muscles, and were lower for muscles of male than female lambs, but were similar for muscles from bulls, heifers and mature cows. Soluble proportions of haem iron were higher for beef than lamb (66% vs. 56% of total iron, P < 0.0001), and percentages, as insoluble haem iron or insoluble and soluble non-haem iron, were lower in beef. For beef semitendinosus muscle, increases in cooking time and temperature led to losses of soluble iron and haem iron, with increases in insoluble and non-haem forms of iron, and also in the level of iron in the cooking juice. Losses of iron in drip from a free meat sample or a sample on a pad were over 90% soluble haem iron and were greater following freezing and thawing due mainly to higher volumes of drip. [ABSTRACT FROM AUTHOR]