A chronological assessment of foraging activities of the Cotton Pigmy Goose,Nettapus coromandelianus Gmelin, 1789 at Dulahara pond,Ratanpur, Chhattisgarh,India

This study was planned to assess the foraging activity of ecological important avian species the N. coromandelianus at Dulahara pond of Ratanpur, Chhattisgarh. In present work we observed the effect of “time of the day” and “photoperiod” on daytime foraging activities of N. coromandelianus. The most applied foraging skills of N. coromandelianus were documented for two repetitive days each for the period of long days (March and April 2015) and short days (December 2015 and January 2016). One-way ANOVA (by SPSS 16.0) was employed to observe the effects of “photoperiod” and “time of the day” on daytime foraging pattern in order to the frequency of foraging techniques. The rhythms in daytime foraging movement were estimated by means of Cosinor rhythmometry at 24 h and 12 h. The current study clarified that the N. coromandelianus mostly applied three main techniques viz., head and neck dipping, diving and striking on which both the diving and striking were the most employed technique while the head and neck dipping was less employed technique during foraging. Moreover, the N. coromandelianus maximally involved for foraging activities during the short day than long day.     

Impact of the flower stalk-boring moth Neoschoenobia testacealis (Lepidoptera: Crambidae) and water-level fluctuations on the flower and fruit production of the yellow water lily Nuphar subintegerrima (Nymphaeaceae) in irrigation ponds of western Japan

The flower and fruit production of the yellow water lily Nuphar subintegerrima and the seasonal occurrence of the flower stalk-boring moth Neoschoenobia testacealis were surveyed in two irrigation ponds in western Japan. Water-level fluctuations at each pond were measured. Flowering was observed from late May to September, and fruiting from late May to October. The yellow water lily produced cumulative numbers of 189 and 181 flowers and 121 and 129 fruits in the two ponds’ quadrats. The fruit setting rates at the two ponds were 0.64 and 0.71, and decreased in the summer. The percentage of bored flower stalks was 16 and 5%. Mature larvae bored flower stalks severely during the summer. Whenever the boring larvae attacked the flower stalks, the flower buds and flowers were aborted. There was a significant negative correlation between the fruit setting rate and the boring rate per month (number of bored flower stalks/number of all flower stalks). Whenever abruptly rising water levels (about 10 cm) submerged the flowers, the flowers were aborted too and could not set fruits. The percentages of non-setting fruit due to the rising water levels at the two ponds were 6 and 8%. Overall, our results indicated that flower stalk boring was a more important factor than water-level fluctuation in the sexual reproduction of N. subintegerrima and that N. subintegerrima was well suited to small irrigation ponds.     

Microbial diversity and composition in acidic sediments of freshwater finfish culture ponds fed with two types of feed: a metagenomic approach

Microbial community profile associated with acidic pond sediments (APS) (pH = 3·0–4·5) of freshwater finfish aquaculture ponds (n = 8) was investigated. Sediment DNA extracted from the eight APS were subjected to high-throughput sequencing of V3 and V4 regions which yielded 7236 operational taxonomic units (OTUs) at a similarity of 97%. Overall results showed higher proportion of bacterial OTUs than archaeal OTUs in all the APS. Euryarchaeota (23%), Proteobacteria (19%), Chloroflexi (17%), Crenarchaeota (5·3%), Bacteroidetes (4·8%), Nitrospirae (3·2%), Nanoarchaeaeota (3%) which together constituted 75% of the microbial diversity. At the genus level, there was high preponderance of methanogens namely Methanolinea (5·4%), Methanosaeta (4·5%) and methanotrops, Bathyarchaeota (5%) in APS. Moreover, the abundant phyla in the APS were not drastically affected by the administration of chicken slaughter waste (R-group ponds) and commercial fish feed (C-group ponds), since 67% of the OTUs generated remained common in the APS of both the groups of ponds. There was a minimal difference of 24–26% of OTUs between C-group and R-group ponds, suggesting the existence of a core microbial community in these ponds driven by acidic pH over the years. This study concludes that microbial diversity in pond sediment was influenced to a lesser extent by the addition of chicken slaughter waste but was majorly driven by acidic nature of the pond.     

Effect of different levels of water salinity on the decomposition of organic manures in a brackish water fish pond soil

Effects of different water salinity levels on the decomposition of the two organic manures cowdung and poultry manure were studied under laboratory condition. Application of the manures increased the free CO₂ content and decreased D.O. levels of water. pH values of soil and water declined slightly on addition of the manures. The amount of nitrogen, released from the organic manures to water and soil phases, increased gradually with the period of incubation but decreased with increase in water salinity levels. NH₄ ⁺ was found to occur in comparatively higher amount than NO₃ ^–, due to prevailing anaerobic environmental conditions. The amount of added organic carbon remaining in the soil decreased gradually as the decomposition proceeded, but recorded slightly higher values with increase in water salinity levels.The results showed that the rates of decomposition of added organic manures were comparatively lower under higher water salinity levels and hence indicated that use of well decomposed manures might be more suitable for use under such water salinities in brackish water fish ponds.This work formed a part of a thesis submitted for the Degree of Doctor of Philosophy to Bidhan Chandra Agricultural University, West Bengal in 1978This work formed a part of a thesis submitted for the Degree of Doctor of Philosophy to Bidhan Chandra Agricultural University, West Bengal in 1978     

Interaction between humic substances and carbohydrates in a Pampasic pond (Argentina)

Interaction between humic substances from a Pampasic pond and carbohydrates was studied. Determinations were performed by gel chromatography using radiolabeled glucose. The results showed that upon lowering the pH the interaction decreases in relation to the steric arrangement that causes the diminution of the accessibility of the available sites. Results of displacement experiments carried out by addition of unlabeled glucose, galactose, saccharose and starch, confirmed that the interaction occurs mainly through labile non specific bonds and is, to a certain degree, independent of the carbohydrate molecular weight involved. This revised version was published online in July 2006 with corrections to the Cover Date.