Community Metabolism in Tropical Undrainable Rural Fish Ponds

The process of community metabolism including primary production and community respiration in eighteen undrainable rural fish ponds in India was quantified using the diurnal oxygen curve method. A considerable portion of the gross primary production that was in the moderate ranges, was consumed for the community respiration. Negative, and low positive values of net primary production indicated the significance of the allochthonous supply in these organic enriched systems. The low values of sediment respiration signified the reduced condition of stagnating sediment acting as energy trap.     

Ecological Study of Freshwater Zooplankton of a Subtropical Pond (Karnataka State,India)

Fortnightly records of the biotic and abiotic conditions in a subtropical natural pond were made over a period of 14 months with a view to find out the abiotic causes of fluctuations in the zooplanktonic populations. Statistical analysis of simple correlations among the abiotic factors revealed direct relationships between water temperature, DO and pH and an inverse relationship between DO and -PO₄ at statistically significant levels (P<0.01). The relationships between the physical and chemical factors and the zooplanktonic groups were evaluated by partial and multiple correlation coefficients. The causes for variation in the populations were established by stepwise multiple regression analysis. The populations of copepods and rotifers, respectively, were correlated at the 5 % and 1 % levels of significance to conductivity and -PO₄ which might be indirectly affected by bicarbonates and phytoplankton growth. The occurrence of two peaks of zooplankton, one in winter and another in postsummer, were observed to follow the Microcystis aeruginosa bloom.     

An evaluation of Secchi disk visibility for estimating plankton density in Fish ponds

Correlation coefficients between Secchi disk visibility (X) in fish ponds and concentrations of chlorophyll a and particulate organic matter were –0.79 (P< 0.01) and –0.83 (P< 0.01), respectively. Different observers may obtain different values for Secchi disk visibility and measurements by the same observer differ with the time of day. Nevertheless, Secchi disk visibility provides a suitable estimate of plankton density for management purposes in ponds were plankton is the primary source of turbidityResearch supported by Hatch Project Alabama 398 and by the Office of Water research and Technology of the Department of the Interior through the Water Resources Research Institute of Auburn, University under provisions of the Water Research Act of 1964.     

宋元时期江南运河对嘉湖平原圩田体系的影响

嘉湖平原传统的圩田开发过程形成的农业模式是中国经典的生态农业模式的代表，其中湖州的桑基鱼塘系统被认定为全球重要农业文化遗产（GIASH），通过对本区域内圩田相关的历史文献记载的梳理与分析发现：嘉湖平原的圩田农业开发历史悠久，宋元时期嘉湖平原地区沼泽地开发过程中形成以江南运河为主干河道的河网，以运河为框架进行了圩田水利的开发。宋元时期根据嘉湖平原内部的地势与水环境差异，北部形成以荻塘运河为中心的溇港圩田开发模式，中部形成以运河和塘河为中心的围田开发模式，南部以湖杭运河和杭嘉运河为中心形成桑基鱼塘和桑基稻田圩田体系。     

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.