COMPARATIVE ASSESSMENT OF TOXICITY OF PHENOL,FORMALDEHYDE, AND INDUSTRIAL WASTEWATER TO AQUATIC ORGANISMS

The toxicity of pure phenol, formaldehyde, and industrial wastewater, containing phenol and formaldehyde, from a resin production plant was evaluated using aquatic organisms from different taxonomic groups. Test organisms included mixed bacterial culture, unicellular green algae Scenedesmus quadricauda (Turp.) Breb., crustacea Daphnia pulex de Geer (daphnids), and fish Oncorhynchus mykiss Call, 1990 (rainbow trout). Formaldehyde was found to be more toxic to the mixed bacterial culture (120h EC₅₀ = 34.1 mg L^-1), algae (24h EC₅₀ = 14.7 mg L^-1), and crustacea (48h EC₅₀ = 5.8 mg L^-1) than phenol. Phenol proved to be more toxic to fish (48h LC₅₀ = 13.1 mg L^-1) than to the mixed bacterial culture (120h EC₅₀ = 510 mg L^-1), algae (24h EC₅₀ = 403 mg L^-1), and crustacea (48h EC₅₀ = 25 mg L^-1). The toxicity of the industrial wastewater to the mixed bacterial culture, algae, and crustacea was caused mainly by formaldehyde, but for fish the presence of phenol in the wastewater proved to be the significant reason for toxicity. Differences in sensitivity of the selected test organisms were also observed, with fish and crustacea being the most sensitive species.     

Aluminium and iron oxides affect the soil structure in a long-term mineral fertilised soil

Journal of Soils and Sediments - The influence of iron and aluminium (hydr)oxide on soil aggregation is still not sufficiently understood. Therefore, we undertook a study on the effects of Al and...     

Landscape relatedness: detecting contemporary fine-scale spatial structure in wild populations

Context

Methods for detecting contemporary, fine-scale population genetic structure in continuous populations are scarce. Yet such methods are vital for ecological and conservation studies, particularly under a changing landscape.

Objectives

Here we present a novel, spatially explicit method that we call landscape relatedness (LandRel). With this method, we aim to detect contemporary, fine-scale population structure that is sensitive to spatial and temporal changes in the landscape.

Methods

We interpolate spatially determined relatedness values based on SNP genotypes across the landscape. Interpolations are calculated using the Bayesian inference approach integrated nested Laplace approximation. We empirically tested this method on a continuous population of brown bears (Ursus arctos) spanning two counties in Sweden.

Results

Two areas were identified as differentiated from the remaining population. Further analysis suggests that inbreeding has occurred in at least one of these areas.

Conclusions

LandRel enabled us to identify previously unknown fine-scale structuring in the population. These results will help direct future research efforts, conservation action and aid in the management of the Scandinavian brown bear population. LandRel thus offers an approach for detecting subtle population structure with a focus on contemporary, fine-scale analysis of continuous populations.

     

The Effect of Intravalvular Liquid Loss on Changes in Escherichia coli Levels in Live,Refrigerated Mussels (Mytilus galloprovincialis)

We investigated the effect of intravalvular liquid loss on changes in Escherichia coli (E. coli) levels in mussels (Mytilus galloprovincialis) harvested in different seasons and refrigerated (5°C) for 72 hours. A positive effect of seawater temperature at the time of harvesting on intravalvular liquid loss was found. No changes in E. coli levels in mussels (flesh and intravalvular liquid), as the result of intravalvular liquid loss, were observed. Levels of E. coli in the flesh decreased, probably as a result of cells dying off, causing the maintenance of E. coli levels in flesh and intravalvular liquid to be stable throughout storage.     

Effects of cage fish farming on phytoplankton community structure,biomass and primary production in an aquaculture area in the middle Adriatic Sea

In this study, we investigated the physical, chemical and biological parameters of the water column at two stations under different trophic conditions during a 1‐year period (from September 2005 to September 2006) in an aquaculture area. The investigation was performed monthly at a station inside the fish farm in Maslinova Bay (middle Adriatic Sea, Croatia) and at a control station located in the Hvar Channel in the vicinity of the farm. The results showed that the concentrations of dissolved nutrients were slightly enhanced at the farm station in comparison with the control station, although those differences were not statistically significant, nor were the differences in oxygen saturation recorded during the investigation period. As opposed to the chemical parameters, considerably higher deviations were recorded for biological parameters as demonstrated by a significant increase in phytoplankton biomass and primary production (measured in situ) at the farm station, particularly during the summer season. Phytoplankton community structure analysis showed that the phytoplankton composition at the farm was mostly determined by seasonal changes rather than by the influence of fish farming. In Maslinova Bay, no causal links were identified between increased biomass and the appearance of toxic species.     

Biological and chemical properties of arable soils affected by long-term organic and inorganic fertilizer applications

 Using soils from field plots in four different arable crop experiments that have received combinations of manure, lime and inorganic N, P and K for up to 20 years, the effects of these fertilizers on soil chemical properties and estimates of soil microbial community size and activity were studied. The soil pH was increased or unaffected by the addition of organic manure plus inorganic fertilizers applied in conjunction with lime, but decreased in the absence of liming. The soil C and N contents were greater for all fertilized treatments compared to the control, yet in all cases the soil samples from fertilized plots had smaller C:N ratios than soil from the unfertilized plots. The soil concentrations of all the other inorganic nutrients measured were greater following fertilizer applications compared with the unfertilized plots, and this effect was most marked for P and K in soils from plots that had received the largest amounts of these nutrients as fertilizers. Both biomass C determined by chloroform fumigation and glucose-induced respiration tended to increase as a result of manure and inorganic fertilizer applications, although soils which received the largest additions of inorganic fertilizers in the absence of lime contained less biomass C than those to which lime had been added. Dehydrogenase activity was lower in soils that had received the largest amounts of fertilizers, and was further decreased in the absence of lime. This suggests that dehydrogenase activity was highly sensitive to the inhibitory effects associated with large fertilizer additions. Potential denitrification and anaerobic respiration determined in one soil were increased by fertilizer application but, as with both the microbial biomass and dehydrogenase activity, there were significant reductions in both N₂O and CO₂ production in soils which received the largest additions of inorganic fertilizers in the absence of lime. In contrast, the size of the denitrifying component of the soil microbial community, as indicated by denitrifying enzyme activity, was unaffected by the absence of lime at the largest rate of inorganic fertilizer applications. The results indicated differences in the composition or function of microbial communities in the soils in response to long-term organic and inorganic fertilization, especially when the soils were not limited. Received: 10 March 1998     

Environmentally friendly methods for controlling pine pitch canker

Fusarium circinatum is a highly virulent invasive pathogen that causes the disease commonly known as pine pitch canker (PPC). On mature trees, the most common symptoms of PPC include resin bleeding, resinous cankers, wilting of needles and dieback. In nurseries the main symptoms are yellowish needles, and wilting of foliage and shoots. PPC is considered one of the most important diseases of conifers globally and at least 60 species of Pinus along with Pseudotsuga menziesii are known to be susceptible. Quarantine regulations are crucial to minimize the risk of new introductions into disease-free countries. However, if these measures fail, implementation of environmentally friendly control methods is currently encouraged in an integrated management approach that minimizes the use of chemicals in forests. This review therefore summarizes current knowledge of biological control using endophytic fungi, bacteria and viruses, and other environmentally friendly methods to control PPC, including thermotherapy, natural products with fungicidal effects, promoters of innate host resistance mechanisms and breeding for resistance. Key research gaps to be addressed for improvement of effective management of this disease are discussed.     

Salinity-induced quiescence in eggs of the calanoid copepod Acartia tonsa (Dana): a simple method for egg storage

We report the effect of salinity and temperature on the viability of stored culture-based subitaneous eggs of the calanoid copepod Acartia tonsa for use of copepods in fish larvae culture. Quiescence induction was recorded at 17 and 25 °C, in salinities from 0 to 30. Quiescence was strongly induced at 0 salinity and partially at 5 in both temperatures. Eggs incubated at 0 salinity for up to 12 days at both temperatures showed a decline in the fraction able to be induced into quiescence by abrupt salinity changes. The hatching success of eggs that were able to enter quiescence stabilized after a 1-day incubation and remained ∼25% viable for 12 days in 17 °C. On the contrary, the 25 °C trial showed a gradual decline in viability until stabilizing ∼10% at day 7 and onwards. Longterm 17 °C incubation for 35 days showed that eggs remained quiescent with a viability of ∼14%. Hence, we recommend salinity storage of A. tonsa subitaneous eggs as a relevant shortterm technique, and a suitable alternative to the recently proposed cold storage of eggs when eggs are to be shipped from the copepod producer to a given fish larvae hatchery.