ECOPERSIA
Volume:1 Issue: 3, Summer 2013

This study was conducted to choose the best species for plantation on a poor drainage soil in southern coast of Caspian Sea, Iran. Nutrient concentrations in live and senescent leaves and soil properties were compared among Alnus subcordata C.A.Mey (N-fixing tree), Populus deltoides­ Marsh. (Non N-fixing tree)and Taxodium distichum (L.) Rich. (Coniferous tree) plantations. In each of these plantations and an adjacent natural forest, six 20×20m plots have been selected according to a 100m × 100m randomly systematic grid. Leaf samples of green trees were collected from the bottom one-third of the tree crown by clipping two small twigs located on opposite sides of the crown (six representative trees were sampled in each plot). Senescence leaves have been collected inside wooden trap-based in each stand. Results revealed different effects of species on soil nutrients. Alnus subcordata increased soil N (%) whereas Populus deltoides­ and Taxodium distichum reduced it.The results of nutrition, litter quality, retranslocation and soil properties indicated that Alnus improve soil quality in comparison with the two others. Keywords

Landslides are natural disasters that annually inflict great damages to public and private properties which may associate with loss of life. In recent decades, research on developing methods for predicting the time of landslide has been one of the significant attempts made by scientists. Since in some type of material, landslides are preceded by undetectable movements that cannot be recorded and revealed by conventional instruments, recording the chemical changes of the water flowing out from the toe of the slopes susceptible to sliding can provide important and reliable indicators of landslide activities and early warning. In this study, changes in the chemical composition of water seeping out from the toe of an active landslide were investigated. This process was studied in a laboratory physical model, in which a sliding surface was simulated and the changes in the ion concentration of potassium (K), sodium (Na), magnesium (Mg), calcium (Ca), sulfate (SO4), chlorine (Cl), and bicarbonate as well as EC and pH in both stable state and in the conditions of slight rupture along the sliding surface were investigated. The results indicated that the appreciable chemical changes in the outflowing water, particularly changes in the concentration of some ions, could be used as suitable indicators for early warning of the landslide occurrence.

Around 80% of the population relies on agriculture, rice being the staple food. Topography urges farmers to cultivate upland rice. The Chinese interest in rubber latex has stimulated farmers to grow rubber, although the technical knowledge regarding tree management and latex processing is poor. A study was conducted in an area in Luang Prabang province to examine the suitability of upland rice and rubber. The major objective was to make a comparison within and between three suitability evaluation methods, two of which are expert-driven whereas the third one was executed by a group of farmers. For the fuzzy model different membership values were set and weighed using the Analytic Hierarchy Process (AHP) technique. According to the Boolean classification 88% of the study area is suitable for upland rice, and 85% is suitable for rubber. The fuzzy method yielded 89% suitable for upland rice and 88% suitable for rubber. Farmers came up with 37% suitable for upland rice and 14% suitable for rubber. Comparison is made between the different methods. A reasonable agreement between farmers’ suitability maps and the expert-based methods is obtained for the upland rice than for the rubber-based land utilization type (LUT). This can be attributed to the lack of know-how on the latter.

Fish larvae have a high requirement of amino acid (AA) for energy production and growth. This study was aimed to increase knowledge of AA profile during feral carp larval ontogeny and estimate larval AA requirements. Larvae were collected randomly at 1, 3, 7, 11, 15, 19, 26 and 33 days post hatch for growth and AA analysis. The composition of total AA changed significantly during ontogeny. The essential AA profile of marine carp showed low correlation with rotifers (R2=0.22). High correlation was found between dry food and early larval ages (R2≥0.7) but was lower in late stage (R2≥0.37). At day 7, when larvae were fed on rotifers, methionine seemed to be the limiting AA and when larvae were fed dry food at day 11, 15, 19, 26 and 33, arginine seemed to be the limiting AA. Larval indispensible AA profile can be used as index of the IAA requirements of carp larvae. Supplementation of larval diet used with limiting AA is one way for compensating the deficient amino acid.

In order to understand the importance of particle size and agglomeration for nano-eco-toxicological studies in aquatic environments, the acute toxicity of two different types (suspended powder and colloidal) of silver nanoparticles (AgNPs) were studied in alevin and juvenilerainbow trout. Fish were exposed to each type of AgNPs at nominal concentrations of 0.032, 0.1, 0.32, 1, 3.2, 10, 32, and 100 mg/L. Lethal concentrations (LC) were calculated using a Probit analysis. Some physical and chemical characteristics of silver nanoparticles were determined. In the case of colloidal form, particles were well dispersed in the water column and retained their size; but in the case of suspended powder, particles were agglomerated to large clumps and precipitated on the bottom. In alevins, the calculated 96 h LC50 values were 0.25 and 28.25mg/L for colloidal and suspended powder AgNPs respectively. In the case of juveniles, the 96h LC50 of colloidal form was 2.16mg/L, but suspended powder did not caused mortality in fish even after 21 days. The results showed that both in alevin and juvenile stages, colloidal form is much toxic than suspended powder; this shows increase of nanoparticles size due to agglomeration, will reduce the toxicity. Silver nanoparticles are toxic materials and their release into the water environment should be avoided.

Acute toxicity (96h-LC50) of potassium permanganate (PM) was determined for Caspian kutum Rutilus frisii kutum at two size classes (1 and 3 g). Static renewal method was used. Fish were exposed to different concentrations of PM and mortality was recorded thereafter, until 96 h. Exposed fish showed behavioral stress indicators. 96h-LC50 was calculated to be 3.204 (3.147-3.260) mg/L for small fish and 3.460 (3.393-3.528) mg/L for large fish. Safe concentration for small and large fish was calculated to be 0.003-0.320 and 0.003-0.342 mg/L, respectively. No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) were 2.6 and 2.8 mg/L for small and 2.8 and 3.0 mg/L for large fish. Results indicated that Caspian kutum is susceptible to PM toxicity; although less than many tested species. Likewise, toxicity of PM significantly decreases with increase in fish weight. Higher tolerance in large fish compared to small fish might be as a result of increased stress resistance and higher quality of these fish.

Mnemiopsis leidyi population activities first were recorded during the coastal observations in 2001 in which its population considerably increased afterward and now sustained the southern Caspian Sea. Maximum summer-autumn M. leidyi abundance was recorded in euphotic layer in 2002 (851±85 ind.m-3) and maximum biomass was in 2001 with 48.1±14.4 g.m-3) while minimum were in aphotic layer. In years 2003 to 2011, M. leidyi abundance and biomass sharply declined to 1-843 ind.m-3 and 0.07-37.7 g.m-3, respectively. The length-frequency distribution of Mnemiopsis showed larval, juveniles and transitional stages that made up 98.6% of the total population. In the southern Caspian Sea, Acartia tonsa was the highest number of mesozooplankton species (36 species) which decreased tenfold after Mnemiopsis invasion during 2001-2010. Fecundity experiments of Mnemiopsis showed the average of 8 eggs. day-1, with a maximum of 35 eggs.day-1which increased with increasing body length. The main food was larger amounts of zooplankton prey such as copepodites and adult of A. tonsa. It seems the sharp decreased of Mnemiopsis abundance could be related the decreasing of ova reproduction; and food ability is the main reasons of M. leidyi sustained in the southern Caspian Sea. The objective of present study was to provide information about parameters influencingthe M. leidyi decreased after initial bloom invasion in the southern Caspian Sea.

Some Biochemical properties of silver carp surimi prepared by application of acid-alkali aided methods were investigated and compared to that of derived by conventional method. In terms of total protein solubility and recovery, lipid reduction, and total pigment extractability and myoglobin removal there was a significant (P<0.05) difference among the treatments. Acid-aided method showed the most efficiency to recover more proteins (86.2%) in comparison to the alkaline-aided (79.8%) and conventional (76.7%) methods. The lipid reduction percentage was recorded as 43.6%, 58.4% and 72.3% for the conventional method, and acid-alkali aided methods, respectively. In terms of total pigment removal, the conventional method showed higher efficiency (P<0.05) compared to the pH-shifting methods. Conversely, fish protein solubilisation by acid-alkali aided techniques was more efficient (P<0.05) compared to the conventional method of making surimi. In conclusion, pH-shifting techniques were superior in comparison with the conventional method in order to recover more functional proteins and to efficiently reduce the lipid and myoglobin content of resultant fish protein isolate.