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Abstract: It is well known that termites enrich organic matter in their nests and alter its properties, but their influence on phosphorus forms is less clear. The aim of our study was to quantify and systemize phosphorus forms in different nest parts (outer wall, inner wall, and central part) of termites of varying feeding guilds and soils in seven dominant Brazilian ecosystems. Organic (Po) and inorganic P (Pi) were analyzed after sequential extraction of six labile and stable P fractions in samples from the Amazon region (Terra firme, and Várzea and Igapó floodplains), the Pantanal, the Atlantic rain forest (Mata Atlântica), the Cerrado and the Caatinga. In addition, selected alkaline extracts were characterized by means of liquid-state 31P NMR spectroscopy. The central part of termite nests contained between 275 and 1871mgkg−1 total P, dominated by Pi in nests of soil/wood interface-feeder termites, but with balanced Po and Pi contents in nests of wood-feeding termites. All Po fractions, and, in most nests, also labile Pi forms were enriched in termite mounds in comparison to soils. The P enrichment was most pronounced in nests of the Terra firme (enrichment factors for labile Pi forms and for Po fractions were 1.7–36.5 and 1.1–16.8, respectively), and the Igapó (labile Pi: 4.1–34.0; Po: 1.1–25.7) where the total P content of the soil was the lowest with 141 and 171mgkg−1. Nests of wood-feeding termites mainly accumulated highly labile resin-Pi (enrichment factor 10.5–36.5) and partially the stable HClconc-Pi fractions, apart from Po, which can be all attributed to the organic food source and food digestion. The soil/wood interface-feeder termites had more variations in their nests, but in general had higher portions of P bonded to minerals. Hence, we conclude that (i) termite activity results in a gross enrichment of labile P forms in the nests, (ii) the P composition in termite nests reflects the major feeding guild, and (iii) the degree of this P enrichment is partly driven by the P stock in the soil. [Copyright &y& Elsevier]

Presents a study on the storage of polycyclic aromatic hydrocarbon (PAH) in a typical cerrado of the Brazilian savanna. Abundance of naphthalene and phenanthrene; Determination of the highest PAH in the bark of trees; Location of the sources of PAH.

Within the last 25 years an intensive agriculture has developed in the highland regions of Mato Grosso state (Brazil), which involves frequent pesticide use in highly mechanized cash‐crop cultures. To provide information on pesticide distribution and dynamics in the northeastern Pantanal basin (located in southern Mato Grosso), we monitored 29 pesticides and 3 metabolites in surface water, sediment, and rainwater of the study area during the main application season. In environmental samples, 19 pesticides and 3 metabolites were detected in measurable quantities, resulting in at least one pesticide detection in 68% of surface water samples (n = 139), 62% of sediment samples (n = 26), and 87% of rainwater samples (n = 91). Surface water samples were most frequently contaminated by endosulfan compounds (α‐, β‐, ‐sulfate), ametryn, metolachlor, and metribuzin, although in low (<0.1 μg L−1) concentrations. Sediment samples exhibited concentrations up to 4.5 μg kg−1 of p,p′‐DDT, p,p′‐DDE, endosulfan‐sulfate, β‐endosulfan, and ametryn. In contrast, rainwater was polluted with substantial amounts of endosulfan, alachlor, metolachlor, trifluralin, monocrotofos, and profenofos (maximum concentrations = 0.3 to 2.3 μg L−1) in the highlands. Lowland rainwater samples taken 75 km from the next application area contained 5‐ to 10‐fold lower mean pesticide concentration than in the highlands. Cumulative deposition rates of the pesticide sum within the study period ranged from 423 μg m−2 in the highlands to 14 μg m−2 in the lowlands. The atmospheric input of pesticides to ecosystems seemed to be of higher relevance in the tropical study area than known from temperate regions. [ABSTRACT FROM AUTHOR]

Abstract: Organic matter is generally enriched in termite nests. Since lignin resists degradation by most termite species, it could be a prominent tracer of the organic matter incorporated into termite nests and released into nest surroundings. Our objective was to quantify the content and alteration degree of lignin in termite nests and the surrounding soils, and to analyze the development of the lignin status from young to older termite nests. We sampled Cornitermes silvestrii earth mounds and the surrounding soil in an extensive grid scheme in a Cerrado savanna in Central Brazil. Older mounds were secondarily inhabited by Nasutitermes kemneri and other inquilines; those mounds and reference soil sites were also sampled. Lignin contents were estimated by the sum of lignin-derived phenols and additionally by mid-infrared spectroscopy followed by a partial least squares regression. Nests inhabited by primary termites had a lignin content of 1952mgkg−1, which was 15 times more than at 10cm depth of the reference soils. In comparison, organic carbon was only enriched by a factor of 2 in primarily inhabited nests. Our accompanying microcosm experiment showed that the lignin composition was not changed during incorporation into termite nests. Elevated lignin contents could still be found at 60cm distance from the nest border as well as up to 60cm soil depth beneath the nests. The lignin content in older nests was only half that of younger nests, and the influence on the nest surroundings was less prominent. Higher acid-to-aldehyde ratios in those older nests indicated that the remaining lignin was oxidized and thus partly degraded during nest aging. We conclude that the savanna termite C. silvestrii enriches lignin in its earth mounds, but that only a minor part enters the soil-protected lignin fraction when nests decay, as most of the lignin is lost during nest aging. [Copyright &y& Elsevier]

Abstract: There have been several reports published which suggest that it is possible that the polycyclic aromatic hydrocarbons (PAHs) naphthalene (NAPH), phenanthrene (PHEN) and perylene (PERY) in tropical environments have a biological source. This source might be related to the activity of termites or their associated microorganisms. We aimed to provide direct evidence for the biological production of NAPH, PHEN and PERY by conducting microcosm experiments in the State of Tocantins, Brazil, in which termite nests (with or without termites) were placed in an enclosed environment in which we controlled all PAH fluxes and monitored changes of PAH stocks. The experiments were carried out with termites from a tropical floodplain forest environment at the Estação Canguçu (Ilha do Bananal) in the State of Tocantins, Brazil. We set up the following treatments: live nest of Nasutitermes cf. minor using PAH-poor wood as food (LNW), live nest of Nasutitermes cf. minor using PAH-poor corn as food (LNC), termite nest without live termites called dead nest (DNC) and dead nest with additional treatment by a combined fungicide/bactericide (FDN) in several replicates. In LNW, LNC, and DNC, there were mean increases of 43%, 21%, and 46% in NAPH stock after 20d while the stocks of the 20 other PAHs studied did not change or even decreased. In contrast, FDN lost 20% of the NAPH stock after 20d of the microcosm experiment because of dissipation and lack of microbial synthesis of new NAPH. In LNW and LNC, low-molecular weight PAHs (acenaphthylene to chrysene) were significantly lost at a mean percentage which was strongly correlated with the octanol–water partitioning coefficient (K OW, r =0.78). This was not the case in DNC and FDN. There were no indications that in the studied termite nests PHEN and PERY were produced. Our microcosm experiments suggest that NAPH can be produced by fungi and bacteria in termite mounds while all other low-molecular weight PAHs are degraded in microcosms with live termite nests. PAH degradation seems to be enhanced by the combined activity of termites and microorganisms. [Copyright &y& Elsevier]