Changing Rule of Physical and Chemical Indicators of Sediment in Tilapia Aquaculture Ponds

To provide basic information for studying balancing mechanism of nutrition environment in aquaculture ponds, sediment samples were collected periodically during the breeding process of tilapia in ponds. Then various types of nutrient content of the samples were detected and the changing rule was summarized. The results showed that dry weight of the sediment and content of TP, TN and TOC generally presented a trend of first increasing and then decreasing. The main production period of each nutrient was from July to September and the production percentage was close to 80% of the total production. The content of NH4^＋-N increased gradually and reached a peak in early August, then maintained at the peak level. NO2^--N content of the sediment in each pond was basically the same in the earlier aquaculture stage and decreased in middle stage with a big difference, then rose again in the later stage.

Evaluation of Physico-Chemical Parameters as Veritable Indicators of Faecal Escherichia coli Contamination of Surface Waters

There is need for alternate quick-search of pathogens’distribution in community water sources,instead of the cumbersome“Escherichia coli detection.”Physical and chemical(physico-chemical)parameters were evaluated as veritable indicators of faecal Escherichia coli contamination of surface waters,using Adada River in Nigeria as case-study.Thirty-two(32)physico-chemical parameters were analyzed in the river(at specified geographical coordinates)for their quality and quantity and connected(using Pearson’s Correlation Analysis)with the distribution of the river’s isolated Escherichia coli.The 32 physico-chemical parameters consist of 11 cations,6 anions,7 physical properties,3 properties relating to oxygen and 5 properties relating to anions/cations.Physico-chemical indices from the analysis,revealed very significant positive correlation relationship of Escherichia coli with the presence of Mg(Magnesium)and K(Potassium)in the dry and rainy season,respectively.E.coli affinity tests(Kirby-Bauer Disc Diffusion)for these metals were also positive.Mg and K also showed significant positive Pearson’s possible paired correlation relationship.From this evaluation,potential index analysis indicated that Mg and K could serve as markers for the faecal bacteria indicators,and possible index for future monitoring of the potability of such surface water.The method is straight forward,cost effective,less cumbersome than other currently existing approaches.

Estimation of Transported Pollutant Load from Small Urban Kahuwa River Micro-catchment in Lake Kivu, Democratic Republic of Congo

This study estimated pollutant load from Kahuwa micro-catchment into Lake Kivu. The micro-catchment was sampled monthly for a year at six locations to capture the contribution of agricultural land, industries and commercial blocks. Both wet and dry depositions in terms of TN （total nitrogen） and TP （total phosphorus） were estimated monthly. The level of pollution was estimated using LISEC index and IPO （organic pollution indices）. Results show that Kahuwa River micro-catchment is polluted mainly by waste dumping sites and industries within the micro-catchment. The general load to the outlet was respectively about 0.35 tons per year （t/yr） for BODs, 1.9 t/yr for COD, 32.73 t/yr for TP and 224.37 t/yr for TN. Atmospheric deposition of nutrient contributed for about 4% and 18% of TP, 3% and 0.01% of TN during dry and wet deposition, respectively.

Estimate of Amino Acid Balance in Nutrition

A new chemical index-imbalance degree (IBD), was proposed on the basis of cluster analysis in multivariate statistical analysis to estimate the extent of amino acid balance in protein. The range of IBD is between 0 and 1, successively corresponding to complete balance and entire imbalance for the amino acid profile of a sample. The amino acid increment model of IBD belongs to an asymmetrical maximum-type, and there is a high correlation between IBD and coefficient of variation (CV). The nutritional value of individual feed can be ranked and clustered according to its IBD; and by calculating the IBD of amixed sample with two or more feedstuffs, it is Possible theoretically to predict whether a synergetic. pheno men on exists and when an optimal mutual complement can happen. If the conceptive frame of IBD extended, it can be used to study the balance of nutrients besides amino acids, and is helpful to realize the automatic distinction and selection in diet formulating.

Continental chemical weathering during the Early Cretaceous Oceanic Anoxic Event(OAE1b): a case study from the Fuxin fluvio-lacustrine basin, Liaoning Province,NE China

This study focuses on Early Cretaceous mudstones from the Shahai and Fuxin formations in the Fuxin continental basin. We analyse chemical weathering, land surface temperatures and palaeoclimates based on chemical weathering indices, and emphasize the implications of continental chemical weathering on nutrient fluxes into lakes and oceans.According to Cr and Ni abundance, Al2O3-TiO2, La/Sc-Th/Co and V-Ni-Th×10 plots, as well as rare earth element(REE)analysis, mudstone samples from the Shahai and Fuxin formations were derived from the same type of provenance comprising mainly felsic igneous rocks. Chemical weathering trends reflected by the Chemical Index of Alteration(CIA),Weathering Index of Parker(WIP) and the Mafic Index of Alteration for Oxidative weathering environments(MIA(O)) are consistent with each other and allow the geological succession to be divided into four stages. Land surface temperatures of the Shahai and Fuxin formations are estimated based on the linear relationship of CIA to temperature,and also can be divided into four stages consistent with those determined from chemical weathering trends. During Stage A(early part of the late Aptian) chemical weathering and land surface temperatures were relatively low and showed characteristic high fluctuations, while Stage B(latest Aptian) represented a transitional period where weathering rates and temperatures increased, and high amplitude fluctuations continued. Conditions changed markedly in Stage C(early Albian) with very high and stable weathering, and warm, humid climates, while in Stage D(middle and late Albian) conditions returned to low chemical weathering and land surface temperatures. These stages of chemical weathering and land surface temperature fluctuations represent responses to global climate fluctuations during the Early Cretaceous, with the early Albian high weathering intensities and warm, humid climates combining to create high nutrient levels that would have flushed through rivers into lakes and ultimately oceans. This correlates stratigraphically with the development of Early Cretaceous black shales during Ocean Anoxic Event 1 b, showing the importance of continental weathering regimes as a causal mechanism for lake and ocean anoxia.