Theoretical speciation of ethylenediamine-N-(o-hydroxyphenylacetic)-N'-(p-hydroxyphenylacetic) acid (o,p-EDDHA) in agronomic conditions

The presence of ethylenediamine-N-(o-hydroxyphenylacetic)-N'-(p-hydroxyphenylacetic) acid (o,p-EDDHA) as the second largest component in commercial EDDHA iron chelates has recently been demonstrated. Here is reported the speciation of o,p-EDDHA by the application of a novel methodology through the determination of the complexing capacity, protonation, and Ca(2+), Mg(2+), Cu(2+), and Fe(3+) stability constants. The pM values and species distribution in solution, hydroponic, and soil conditions were obtained. Due to the para position of one phenol group in o,p-EDDHA, the protonation constants and Ca and Mg stability constants have different values from those of o,o-EDDHA and p,p-EDDHA regioisomers. o,p-EDDHA/Fe(3+) stability constants are higher than those of EDTA/Fe(3+) but lower than those of o,o-EDDHA/Fe(3+). The sequence obtained for pFe is o,o-EDDHA/Fe(3+) >/= o,p-EDDHA/Fe(3+) > EDTA/Fe(3+). o,p-EDDHA/Fe(3+) can be used as an iron chelate in hydroponic conditions. Also, it can be used in soils with limited Cu availability.     

Trace Metal Content Trend of Mussel Perna Perna (Linnaeus, 1758) from the Atlantic Coast of Southern Brazil

The concentration assessment of Hg, Pb, Cd, Cu, Zn, Cr, Mnand Fe in marine mussels Perna perna, sampled at 15stations along the 800 km Southern Brazilian Coast, has beencarried out. Samplings were taken twice, in summer andwinter of 2000. The concentrations found were lower thansimilar studies carried out along the Central Coast of Brazil andlower than the maximum limits permitted in bivalve molluscsdesignated for human consumption (Brazilian, Spanish andLuxembourg legislation sets). The data also showed lowervalues compared with other regions of the world. Thecomparison of present data with the data obtained 10 years agoat the same stations did not show significant differences,consequently the concentrations found could be used asbaseline values.     

Comparing taxonomic levels of epigeal insects under different farming systems in Andalusian olive agroecosystems

The intensification of olive production methods in southern Spain, has involved a widespread use of chemicals and the progressive loss of many Mediterranean forest patches, natural landscapes and semi-natural vegetation. Species level inventories require an enormous amount of time and financial resources, mainly due to the necessity of employing taxonomists in the early stages of a study. The use of a higher taxonomic level is particularly useful when rapid biodiversity surveys are required. This survey investigates the reliability of a rapid method to detect which high taxonomic level of epigeal insects could best distinguish different farming systems in olive agroecosystems, taking into account three higher taxonomic categories as surrogate measures of insect diversity: orders for all the insects, families of Coleoptera and carabid morphospecies. Insects were collected in pitfall traps in olive orchards under organic, integrated and conventional farming systems in two provinces in Andalusia (Córdoba and Granada) with different surrounding landscapes over three different years. In 1999 and 2000 a study of trends over time was undertaken between March and October of both years in Granada, and in 2003 a geographically extended study was conducted in 18 different orchards during pre-blooming and post-blooming periods in Granada and Córdoba. To rapidly assess biodiversity in olive agroecosystems by examining soil communities, in order to classify farming systems on a regional scale, the taxonomic level of order seems to be a more reliable approach than a lower taxonomic level in insects. This methodology could be used as a possible useful short-cut to assess biodiversity in olive orchards at a local scale, the order surrogacy being useful when results are required rapidly and in a context of limited financial resources.     

Gas exchanges and chlorophyll fluorescence of young coffee plants submitted to water and nitrogen stresses

Abstract

This research aims to evaluate the impact of nitrogen deprivation and water stress on gas exchange and chlorophyll fluorescence in young plants of five cultivars of Arabic coffee. A factorial experiment 5 (cultivars) × 3 (treatments: control without stress, water stress of ?1.5?MPa and stress of N – 0.0?mmol L^?1 N) was carried out in a complete randomized block design with three replicates. Before being submitted to the treatments, the plants were grown in a greenhouse for 240?days, and then transferred to a growth chamber under controlled conditions. Subsequently, after the experimental period of 96?h we measured photosynthetic rate (A), stomatal conductance to water vapor (g_s), transpiratory rate (E), internal and external carbon ratio (Ci/Ca), water use efficiency (A/E), electron transport rate (ETR), actual quantum yield of PS II electron transport (φFSII), and maximum photochemical efficiency of PS II (Fv/Fm). Water stress reduced A, g_s, E, A/E, ETR, φFSII, and Fv/Fm. The nitrogen deficiency reduced ETR, φFSII, and Fv/Fm. Under short-term water stress Catuaí Vermelho maintain the A values due to better stomatal control, reduced water lost by transpiration (E) and better water use efficiency A/E, while Mundo Novo and Acauã show lower damage to Fv/Fm. Short-term nitrogen stress has low impact on A of young plants of Coffea arabica cultivars with adequate N-nutrition.     

Environmental Quality and Cytogenotoxic Impact of the Waters of a Stream Receiving Effluents from Tannery Industry

Water, Air, & Soil Pollution - Cu-based copper nanoclusters have generated a great deal of interest based on for their fluorescent and catalytic properties. However, as heterogeneous catalysts,...     

Effects of bird and bat exclusion on coffee pest control at multiple spatial scales

Context

Despite the key role of biological control in agricultural landscapes, we still poorly understand how landscape structure modulates pest control at different spatial scales.

Objectives

Here we take an experimental approach to explore whether bird and bat exclusion affects pest control in sun coffee plantations, and whether this service is consistent at different spatial scales.

Methods

We experimentally excluded flying vertebrates from coffee plants in 32 sites in the Brazilian Atlantic Forest, encompassing a gradient of forest cover at landscape (2 km radius) and local (300 m) spatial scales, and quantified coffee leaf loss, as an indicator of herbivory, and fruit set.

Results

Leaf loss decreased with higher landscape forest cover, but this relation was significantly different between treatment and control plants depending on local forest cover. On the other hand, fruit set responded to the interaction between treatment and local forest cover but was not affected by landscape forest cover. More specifically, fruit set increased significantly with local forest cover in exclusion treatments and showed a non-significant decrease in open controls.

Conclusions

These results suggest that services provided by flying vertebrates are modulated by processes occurring at different spatial scales. We posit that in areas with high local forest cover flying vertebrates may establish negative interactions with predaceous arthropods (i.e. intraguild predation), but this would not be the case in areas with low local forest cover. We highlight the importance of employing a multi-scale analysis in systems where multiple species, which perceive the landscape differently, are providing ecosystem services.

     

Technical and economic feasibility of integrating seahorse culture in shrimp/oyster farms

Integrated multi‐trophic aquaculture systems (IMTA) are building ecosystems designed to produce aquatic organisms with less environmental impact. We have developed a simple system and a management strategy for introducing seahorse (Hippocampus spp.) culture in shrimp/oyster farms to increase economic sustainability. The system includes broodstock, nursery and grow‐out phases of Hippocampus reidi G. culture. We performed a test in a 42.4‐ha marine shrimp/oyster farm, which showed that this system is technically feasible. Then, we performed a partial budget analysis including cost‐return, cash flow and financial feasibility analysis. More than 12 000 marketable size seahorses may be produced in 402 m² annually. Initial investment was only US$ 21 103.00. The benefit–cost ratio was ~US$ 20.00 for each US$ 1.00 spent, internal rate of return was 131% and payback period <2 years. In conclusion, the introduction of seahorse in shrimp/oyster IMTA system is technically feasible, profitable, resilient and shows high liquidity. This system may be easily established in developing countries and has potential to provide seahorses to supply different markets (live specimens for the marine aquarium trade and dried specimens for traditional Chinese medicine and the curio trade). In addition, it can indirectly contribute to preserve natural populations.     

Tolerance response to ammonia and nitrite in hatchlings paralarvae of <Emphasis Type="Italic">Octopus vulgaris</Emphasis> and its toxic effects on prey consumption rate and chromatophores activity

Ammonia and nitrite are among the most important water quality parameters. The aim of this study was to determine the acute toxicity of unionized ammonia and nitrite on newly hatched Octopus vulgaris paralarvae. Concretely, survival, feeding and chromatophore activity were examined under different NH₃ and NO₂ ⁻ concentrations. The median lethal concentration (LC 50) determined for 24 h was 10.7 ppm for NH₃ and 19.9 ppm for NO₂ ⁻. Based on these results, a concentration range was chosen to test the effect of this environmental contaminants in feeding and chromatophore activity (range between 2.5 and 20 ppm for feeding and 10 and 30 ppm for chromatophore activity), resulting in modifications in both parameters. In fact, a significant decrease (P < 0.05) in Artemia nauplii consumption by the paralarvae was observed with an increase in NH₃ and NO₂ ⁻. Similarly, the chromatophore activity was also affected by concentration of these contaminants, with decreasing response (P < 0.05) when submitted to stressful situations, as the ammonia and nitrite concentration was increased.     

Settling velocity and total ammonia nitrogen leaching from commercial feed and faecal pellets of gilthead seabream (Sparus aurata L. 1758) and seabass (Dicentrarchus labrax L. 1758)

The physico-chemical characteristics of particulate wastes of Sparus aurata and Dicentrarchus labrax were investigated. Changes in the dimensions, settling velocity and total ammonia nitrogen (TAN) leached from commercial feed pellets were investigated after soaking. Also, the settling velocity and TAN leached from faecal pellets of these fish were assessed at 15 and 25 °C. The settling velocity of feed pellets was influenced positively by pellet weight and negatively by immersion length as a result of changes in pellet dimensions after soaking. The settling velocity of faecal pellets was determined by pellet weight. The experimental design did not allow identification of any consistent effect of water temperature on settling velocity. Total ammonia nitrogen leaching over time from feed and faecal pellets was successfully explained by means of a first-order kinetic equation. For feed pellets, water temperature significantly affected the speed of the process and the time at which the maximum TAN leached was reached, but did not influence the maximum TAN leached. Leaching was related to feed pellet size, and so the smaller the pellet, the higher the leaching. Total ammonia nitrogen leaching from faecal pellets was greater per unit weight than in feed pellets. However, neither water temperature nor fish species influenced TAN leaching from faeces.