scholarly journals Phosphorus and arsenic distributions in a seasonally stratified, iron- and manganese-rich lake: microbiological and geochemical controls

2015 ◽  
Vol 12 (6) ◽  
pp. 708 ◽  
Author(s):  
Adam Hartland ◽  
Martin S. Andersen ◽  
David P. Hamilton
Keyword(s):  
New Zealand ◽  
Eutrophic Lake ◽  
Surface Mixed Layer ◽  
Iron Hydroxides ◽  
Colloidal Iron ◽  
Fe And Mn ◽  
Manganese Hydroxides ◽  
Highly Correlated ◽  
Seasonal Stratification ◽  
Iron And Manganese

Environmental context Despite being present at trace concentrations, arsenic and phosphorus are among the most important of freshwater contaminants. This research highlights the biogeochemical coupling of both elements in a New Zealand lake. We find that the mineralisation of organic residues coupled to the dissolution of colloidal iron and manganese hydroxides may be an important driver of the bioavailability of phosphorus and arsenic. Abstract Seasonal stratification in temperate lakes greater than a few metres deep provides conditions amenable to pronounced vertical zonation of redox chemistry. Such changes are particularly evident in eutrophic systems where high phytoplankton biomass often leads to seasonally established anaerobic hypolimnia and profound changes in geochemical conditions. In this study, we investigated the behaviour of trace elements in the water column of a seasonally stratified, eutrophic lake. Two consecutive years of data from Lake Ngapouri, North Island, New Zealand, demonstrate the occurrence of highly correlated profiles of phosphorus, arsenic, iron and manganese, all of which increased in concentration by 1–2 orders of magnitude within the anaerobic hypolimnion. Stoichiometric and mass-balance considerations demonstrate that increases in alkalinity in hypolimnetic waters were consistent with observed changes in sulfate, Fe and Mn concentrations with depth, corresponding to dissimilatory reduction of sulfate, FeIII and MnIV hydroxides. Thermodynamic constraints on Fe, Mn and Al solubility indicate that amorphous FeIII, MnIV hydroxides most probably controlled Fe and Mn in the surface mixed layer (~0 to 8m) whereas AlIII hydroxides were supersaturated throughout the entire system. Surface complexation modelling indicated that iron hydroxides (HFO) potentially dominated As speciation in the lake. It is likely that other colloidal phases such as allophanic clays also limited HPO42– activity, reducing competition for HAsO42– adsorption to iron hydroxides. This research highlights the coupling of P, As, Fe and Mn in Lake Ngapouri, and the apparent role of multiple colloidal phases in affecting P and As activity within overarching microbiological and geochemical processes.

scholarly journals On iron flagellates

1946 ◽  
Vol 232 (588) ◽  
pp. 311-342 ◽  
Keyword(s):  
Organic Substances ◽  
Habitat Conditions ◽  
Liquid Media ◽  
Brown Colour ◽  
Fe And Mn ◽  
Iron Deposits ◽  
Manganese Compounds ◽  
Small Content ◽  
Iron And Manganese

The physiology and morphology of iron- and manganese-depositing flagellates are investigated by means of cultural experiments, with special reference to Anthophysa vegetans Stein, Siderodendron manganiferum n.gen., n.sp., Siphomonas Fritschii n.gen., n.sp. and Bikosoeca ( Poteriodendron ) petiolata (Stein) n.comb. Anthophysa multiplies in various liquid media containing small amounts of organic substances, hay decoction being specially favourable. Still better results are achieved with soil-water cultures, which afford the only successful cultures of Siderodendron and Siphomonas , while Bikosoeca also grows well in hay infusions. Addition of Fe" and Mn" is essential. The brown colour of biological iron deposits is shown to be due to admixture of manganese compounds, while mere ferric precipitates are in microscopical amounts almost colourless. Anthophysa and Siderodendron deposit more manganese than iron, so that their stalks appear brown, while those of Siphomonas are generally light brown. The envelopes of Bikosoeca are almost entirely composed of ferric compounds and appear colourless or faintly yellowish. All four organisms exhibit various modifications according to the habitat conditions. The formation of stalks and envelopes respectively depends on the availability of the relevant metals in the form of lower oxides, but the organisms here described can also exist without producing these structures. The oxidation of ferrous and manganese compounds is catalysed by the cells of these flagellates, although the role of this process in the cellular metabolism is not known. Nutrition is holozoic, chiefly by ingestion of bacteria. Like other holozoic flagellates these organisms cannot exist in the presence of an abundant bacterial vegetation owing to the resulting lack of oxygen. They thrive in quiet, well-aerated waters, with a small content of organic substances, above zones in which Fe and Mn compounds are reduced and from which ferrous and manganous compounds diffuse to the overlying oxidation zone, where these flagellates deposit Fe"' and Mn'" in a morphologically defined form. ‘Iron’ flagellates generally live in association and competition with iron bacteria of the Leptothrix group, the removal of which produces much better growth. A description of the relevant flagellates and of their appearance under various conditions, as well as diagnoses of Siderodendron and Siphomonas , are given.

Interception frequency of exotic bark and ambrosia beetles (Coleoptera: Scolytinae) and relationship with establishment in New Zealand and worldwide

2006 ◽  
Vol 36 (2) ◽  
pp. 289-298 ◽  
Author(s):  
Eckehard G Brockerhoff ◽  
John Bain ◽  
Mark Kimberley ◽  
Milos Knížek
Keyword(s):  
United States ◽  
New Zealand ◽  
Bark Beetles ◽  
Solid Wood ◽  
Ips Typographus ◽  
Northern Asia ◽  
Forest Pests ◽  
The World ◽  
Bark And Ambrosia Beetles ◽  
Highly Correlated

Scolytinae species are among the most damaging forest pests, and many of them are invasive. Over 1500 Scolytinae interceptions were recorded at New Zealand's borders between 1950 and 2000. Among the 103 species were Dendroctonus ponderosae, Ips typographus, and other high-risk species, but actual arrivals probably included many more species. Interceptions were primarily associated with dunnage, casewood (crating), and sawn timber, and originated from 59 countries, mainly from Europe, Australasia, northern Asia, and North America. New Zealand and United States interception data were highly correlated, and 7 of the 10 most intercepted species were shared. Interception frequency and establishment in New Zealand were not clearly related. By combining New Zealand and United States interceptions of true bark beetles we obtained data on species found in shipments from around the world. Logistic regression analysis showed that frequently intercepted species were about four times as likely as rarely intercepted species to be established somewhere. Interception records of wood and bark borers are valuable for the prediction of invaders and for our general understanding of invasions. The use of alternatives to solid wood packaging, such as processed wood, should be encouraged to reduce the spread of invasive wood and bark borers.

scholarly journals Accumulation of Zn, Cu, Fe, Mn and Pb due to brick manufacturing in agricultutral soils and plants

2016 ◽  
Vol 25 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Abdul Halim Farhad Sikder ◽  
Sayma Khanom ◽  
Md Faruque Hossain ◽  
Zakia Parveen
Keyword(s):  
Heavy Metals ◽  
Agricultural Soil ◽  
Poor Quality ◽  
Maximum Amount ◽  
Agricultural Crops ◽  
Brick Kilns ◽  
Fe And Mn ◽  
Iron And Manganese

Experiment was carried out to assess the concentration of Zn, Cu, Pb, Fe and Mn in agricultural soil and plant near selected brick kilns. Soils and plants samples were collected from four points such as 250, 500, 1000 and 1500 m away from brick kilns. Three metals were found at elevated levels in the soils near brick kilns such as, Pb (92.5 to 214 mg/kg), Zn (86 to 156 mg/kg) and Cu (24.7 to 46.9 mg/kg). It may be caused due to burning of poor quality coal and fire woods. The uptake of heavy metals in the nearest areas (250 m) of the brick kilns was significantly higher than the areas far from the brick production and their concentrations range from 7 to 543 mg/kg for Pb, 23 to 101 mg/kg for Zn, 10 to 41 mg/kg for Cu, 35 to 1309 mg/kg for Fe and 26 to 126 mg/kg for Mn. Results indicated that soils and plants accumulated maximum amount of micronutrients within 500 to 1000 m distance from brick kilns significantly decreased with distance. Iron and manganese were not polluting the soils near brick kilns but affecting the plants. Therefore, it can be suggested that no agricultural crops should be grown within 1000 m distance from a brick kiln.Dhaka Univ. J. Biol. Sci. 25(1): 75-81, 2016

scholarly journals Extractable aluminium, iron and manganese in mineral soils: I Dependence of extractability on the pH of oxalate, pyrophosphate and EDTA extractants

1989 ◽  
Vol 61 (2) ◽  
pp. 73-78 ◽  
Author(s):  
Raina Niskanen
Keyword(s):  
Supporting Electrolyte ◽  
Pka Values ◽  
Fe And Mn ◽  
Mineral Soils ◽  
Ph Range ◽  
Iron And Manganese

Al, Fe and Mn in two mineral soils were extracted by 0.05 M and 0.02 M oxalate and pyrophosphate and 0.02 M EDTA solutions the pH of which was adjusted to values ranging from 1.7 to 11.0. The extractability of metals tended to decrease as the pH rose and as the deprotonation of extractant acid, expressed as pKa values, progressed. The reduction in extractability of metals by oxalate was rather steep at pH > 4, whereas the extractability by pyrophosphate remained moderate at a wider pH range. The extractability of metals by EDTA (pH 3.6—7.3) was lower than that by oxalate and pyrophosphate. Extractability was lower in the absence of the studied oxyacid anions and with 0.01 M KCI as the supporting electrolyte at a pH between 2 and 11 than in their presence.

scholarly journals Extracting Reliable Paleo-Ocean Temperatures at Southern Mid-Latitudes During the Greenhouse to Icehouse Transition: a LA-ICP-MS Study of the Trace Element Chemistry of Eocene Foraminifera from New Zealand

2021 ◽  
Author(s):  
◽  
John Benjamin Creech
Keyword(s):  
New Zealand ◽  
Trace Element ◽  
Benthic Foraminifera ◽  
Inductively Coupled Plasma ◽  
Middle Eocene ◽  
Isotope Analysis ◽  
Time Interval ◽  
Northern Margin ◽  
Icp Ms ◽  
Fe And Mn

<p>Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used to measure in situ elemental (Mg, Al, Mn, Zn, Sr, Ba/Ca) ratios of 13 species of variably preserved early to middle Eocene planktonic and benthic foraminifera from the mid-Waipara River section, north Canterbury, New Zealand. The sediments from Waipara River were deposited at bathyal depths (ca. 1000 m) on the northern margin of the east-facing Canterbury Basin at a paleo-latitude of ca. 55 dgrees S. LA-ICP-MS analysis yields trace element depth profiles through foraminifera test walls that can be used to identify and exclude zones of surficial contamination and infilling material resulting from diagenetic coatings, mineralisation and detrital sediment. Screened Mg/Ca ratios are used to calculate sea temperatures from late early to early middle Eocene (ca. 51 to 46.5 Ma), a time interval that appears to span the termination of the Early Eocene Climatic Optimum (EECO). During this time, sea surface temperatures (SST) varied from 30 to 24 degrees C and bottom water temperatures (BWT) from 21 to 14 degrees C. Comparison of Mg/Ca sea temperatures with published delta superscript 18 O and TEX subscript 86 temperature data from the same samples (Hollis et al., 2009) shows close correspondence, indicating that LA-ICP-MS can provide reliable Mg/Ca sea temperatures even where foraminiferal test preservation is less than ideal. Agreement between the three proxies also implies that Mg/Ca - temperature calibrations for modern planktonic and benthic foraminifera can generally be applied to Eocene species, although some species (e.g., V. marshalli) show significant calibration differences. The Mg/Ca ratio of the Eocene ocean is constrained by our data to be 35-50% lower than the modern ocean depending on which TEX86 - temperature calibration is used to compare with the Mg/Ca sea temperatures (Kim et al., 2008; Liu et al., 2009). Sea temperatures derived from oxygen isotope analysis of foraminifera from mid-Waipara show amplified variability relative to the Mg/Ca and TEX86 derived temperatures. While this difference might be attributed to the oxygen isotopes being more susceptible to diagenetic effects, the data may be consistent with the growth and collapse of significant global ice sheets during cool periods in the Eocene on timescales of ca. 0.5 Myr. The timing of the termination of the EECO in the reconstructed climate record from mid-Waipara is consistent with other published climate records (Tripati et al., 2003, 2005; Zachos et al., 2008).  A large decrease in foraminiferal Mn/Ca ratios up the mid-Waipara section is observed with the youngest samples having Mn/Ca ratios similar to modern foraminifera. This does not appear to be a diagenetic fingerprint as foraminiferal preservation is generally poorer up-section. Global cooling following the EECO may have led to enhanced biological productivity and uptake of Fe and Mn, thereafter producing an ocean with Mn concentrations more similar to the present ocean. This hypothesis is consistent with that proposed to explain changes in the thallium isotope ratios of Fe and Mn crusts observed at this time (Nielsen et al., 2009).</p>

scholarly journals ‘Community’: A Q study exploring perspectives in community governance settings in Taranaki, New Zealand

2021 ◽  
Author(s):  
◽  
Te Aroha Hohaia
Keyword(s):  
Decision Making ◽  
New Zealand ◽  
Q Methodology ◽  
The Political ◽  
Political Practice ◽  
Community Governance ◽  
Policy Proposal ◽  
Space Factor ◽  
Local Decision ◽  
Highly Correlated

<p>Attend any public meeting in Taranaki and, more often than not, one will hear the word ‘community’ used to bolster a policy proposal, or oppose it. But when that happens, what exactly is meant by ‘community’? Taking advantage of her position as an embedded participant, the author of this thesis set out to understand what ‘community’ means to those who occupy roles of influence in decision-making settings in Taranaki, Aotearoa- New Zealand. To the study’s informants and participants, a deceptively simple question was put: ‘what do you understand by ‘community’?’  The set of techniques used to elicit responses to this question was William Stephenson’s Q Methodology. Data collection began with 29 informant interviews from which 45 statements representative of what is understood by ‘community’ were extracted. Those statements were rank-ordered by 35 participants generating 47 Q sorts (the mechanism by which each viewpoint was captured). Using PQMethod 2.35, a three-factor solution generated through principal components analysis and subjected to a varimax rotation was selected for further analysis.  The interpretation of the results substantiated three somewhat highly correlated, yet nuanced perspectives where ‘community’ is:  ▪ ‘Everyone and we’re all in this together’ (Factor 1), ▪ ‘Well... it depends’ given the multiplicity of interests (Factor 2), and ▪ ‘It’s everything’ (Factor 3).  The primacy of relationships and expectations to contribute to where one lives provide the basis for consensus. The nuance is in the scope and reach in terms of who counts, what matters and why it is important at a given point in time. The subsequent discussion noted there is still no agreement on a definition of ‘community’ and its malleability in meaning makes ‘community’ useful for furthering political interests. Its use in the community governance settings of this study reflects the pragmatism of everyday life. ‘Community’ is affirmed as a concept that frames policy discourse.  This study also identifies ‘community’ as a practice and as a way of governing that frames policy responses where the basis for ‘community’ is as:  ▪ A preference for face-to-face interaction and usually over a cup of tea (Factor 1), ▪ A strategy of enabling that is realistic and pragmatic (Factor 2), and ▪ An account of the integrated connections to places, with people and to events across time and space (Factor 3).  The study opens up new ground as the collection, analysis and interpretation of first- person, vested responses from those ‘doing’ ‘community’ in community governance settings is missing from the scholarly and practitioner literature. This study forms a bridge in an identified gap between those who theorise in the political philosophy of ‘community’ and those who advocate in the political practice of ‘community’.  Furthermore, the three perspectives identified and discussed in this study also lead to a proposition that the phrase ‘governing communities’ would be a more apt and authentic alternative to ‘community governance’. Such a development is positioned as the next step in the evolution of the theory surrounding local decision-making and local government in New Zealand and as a normative model for political practice.</p>

scholarly journals Iron and Manganese Retention of Juvenile Zebrafish (Danio rerio) Exposed to Contaminated Dietary Zooplankton (Daphnia pulex)—a Model Experiment

2020 ◽  
Vol 199 (2) ◽  
pp. 732-743
Author(s):  
Petra Herman ◽  
Milán Fehér ◽  
Áron Molnár ◽  
Sándor Harangi ◽  
Zsófi Sajtos ◽  
...  
Keyword(s):  
Danio Rerio ◽  
Daphnia Pulex ◽  
Negative Influence ◽  
Fish Growth ◽  
Trophic Chain ◽  
Concentration Data ◽  
Significant Difference ◽  
Fe And Mn ◽  
The Relationship ◽  
Iron And Manganese

AbstractIn present study the effect of iron (Fe) and manganese (Mn) contamination was assessed by modeling a freshwater food web of water, zooplankton (Daphnia pulex), and zebrafish (Danio rerio) under laboratory conditions. Metals were added to the rearing media of D. pulex, and enriched zooplankton was fed to zebrafish in a feeding trial. The elemental analysis of rearing water, zooplankton, and fish revealed significant difference in the treatments compared to the control. In D. pulex the Mn level increased almost in parallel with the dose of supplementation, as well as the Fe level differed statistically. A negative influence of the supplementation on the fish growth was observed: specific growth rate (SGR%) and weight gain (WG) decreased in Fe and Mn containing treatments. The redundancy analysis (RDA) of concentration data showed strong correlation between the rearing water and D. pulex, as well as the prey organism of Fe- and Mn-enriched D. pulex and the predator organism of D. rerio. The bioconcentration factors (BCF) calculated for water to zooplankton further proved the relationship between the Fe and Mn dosage applied in the treatments and measured in D. pulex. Trophic transfer factor (TTF) results also indicate that significant retention of the metals occurred in D. rerio individuals, however, in a much lower extent than in the water to zooplankton stage. Our study suggests that Fe and Mn significantly accumulate in the lower part of the trophic chain and retention is effective through the digestive track of zebrafish, yet no biomagnification occurs.

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