Phosphorus Bioavailability In Sediments Research Articles

Oyster culture changed the phosphorus speciation in sediments through biodeposition

Phosphorus speciation in the sediments is regulated by a series of physicochemical and microbial processes, and directly affects water phosphorus pool. However, the influence of culture activities and microbial metabolism on the sedimentary phosphorus speciation is poorly studied. In this study, we compared the abundance of distinguishable phosphorus phases and other physicochemical properties of sediments from oyster-farming areas and reference areas. The Geochip 5.0 technique was introduced to reveal the microbiological mechanisms of phosphorus metabolic alteration. The results showed that oyster culture enhanced the bioavailability of phosphorus in sediments. The free organic phosphorus was reduced significantly, whereas the free inorganic phosphorus and iron-bound phosphorus greatly increased in the oyster culture area (P ≤ 0.05). Moreover, the results of Geochip showed that the oyster culture reshaped the microbial network structure in sediments, with typical phosphate-solubilizing and phosphorus-accumulating microbes being enriched by 17.76% and 10.60%. The abundance of functional genes related to the main phosphorus cycle pathways were also significantly increased (P ≤ 0.05) in the culture area compared to the reference area. This work suggested that oyster culture can greatly improve the microbial phosphorus metabolism and provided insights into the environmental recovery and reconstruction from marine aquaculture activities.

Evaluation of phosphorus bioavailability in El Mex Bay and Lake Mariut sediments

Phosphorus (P) fractions and their bioavailability in the sediments from El Mex Bay and Lake Mariut in Egypt were investigated using different chemical extraction methods. Sodium bicarbonate (NaHCO3) extractable P (Olsen-P) was the largest fraction (14.42%), followed by algal available P (AAP) (3.56%), water soluble P (WSP) (0.79%), and readily desorbable P (RDP) (0.06%) for El Mex Bay. While AAP contributed 9.94% to total P in sediments from Lake Mariut, Olsen-P 8.53%, WSP 4.11%, and RDP 0.92%. Summation of the bioavailable P fractions didn’t exceed the sediment quality guidelines, and, therefore, P doesn’t represent a danger to marine organisms. Correlation coefficients showed that no apparent relations between total P (TP) and iron (Fe), aluminum (Al), and calcium (Ca) in the sediments. Furthermore, Fe:P ratio was less than 15 indicting that there was not enough Fe in surface sediments to bind to P at most of the sampling sites. The positive correlation between TP and organic matter (OM) for Lake Mariut and El Mex Bay sediments indicated that the organic matter content of the sediment was a useful predictor of the total phosphorus content. Data from this study constitute a baseline of phosphorus bioavailability in sediments from El Mex Bay and Lake Mariut and could be used as a reference for future studies on the changes of bioavailable and residual phosphorus fractions over time.

Fractionation and bioavailability of phosphorus in sediments of Huaihe River, China

<h3>Background</h3> Atrial fibrillation (AF) is one of the most common sustained cardiac arrhythmia. It is associated with significant morbidity, mortality and poor quality of life. This is the reason why it is very important to closely follow its treatment. Amiodarone is one of the most frequently used antiarrhythmic drugs in patients with AF both in prophylaxis and treatment. However, the treatment with this drug results in high healthcare resource use and costs due to its poor safety profile. <h3>Purpose</h3> The objective of this study was to assess the plasmatic concentration of amiodarone in patients with AF and also to identify possible factors that could influence it. The results were correlated with used doses, with concomitantly administered drugs, renal and liver function. <h3>Material and methods</h3> A prospective observational study was conducted in 27 consecutive patients treated with amiodarone from May to July 2017 in a Clinical University Hospital. The patients included met our inclusion criteria. HPLC-MS was the device used to determine the plasma concentration of amiodarone. <h3>Results</h3> The mean age of those 27 included patients was 65/6±11 years, 44.4% females. The used doses were 200 mg or 400 mg/day. In our patients, plasmatic concentration was given in a therapeutic interval (500–2,500 ng/ml) to 51.8%. In the patients with lower plasmatic concentrations of amiodarone, the drugs associated in the therapeutic plan belonged to: diuretics (furosemide), beta-blockers, statins, antiplatelets (clopidogrel), fluoroquinolones (ciprofloxacine) and non-steroidal anti-inflammatory drugs. It was observed that there was a statistically significant difference between the plasmatic concentrations of amiodarone in patients treated with furosemide vs patients treated concomitantly with other drugs. The interactions between other mentioned drugs and amiodarone were not registered. It was observed that an increase in transaminases or creatinine is correlated with an increase in amiodarone’s plasmatic concentration. <h3>Conclusion</h3> 48.2% of the patients with AF under chronic treatment with amiodarone had the plasmatic concentration of amiodarone out of the therapeutic range. We can report an underuse of amiodarone for these patients. It was found that there was a significant interaction between furosemide and amiodarone. In order to confirm this interaction, we need to continue the research on a larger sample. <h3>References and/or Acknowledgements</h3> Thanks to all the collaborators. No conflict of interest

Evaluation of phosphorus bioavailability in sediments of the shallow lakes in the middle and lower reaches of the Yangtze River region, China

Phosphorus (P) fractions and their bioavailability in the sediments from the middle and lower reaches of the Yangtze River region were investigated using different chemical extraction methods. The results show that the contents of bioavailable P in the sediments extracted by different extraction procedures varied greatly. But their rank order was similar. Potentially releasable P (PRP) was the largest, followed by algal available P (AAP), NaHCO3 extractable P (Olsen-P), water soluble P (WSP), and readily desorbable P. PRP contributed approximately 60% to total P (TP) in most sediments, AAP 20%, Olsen-P 15%, WSP 2%, and readily desorbable P (RDP) 0.5%. For the heavily polluted sediments, their bioavailable P extracted from TP mainly originated from inorganic P (IP), IP mainly originated from NaOH–P, the bioavailable P concentrations can be evaluated by measuring the concentrations of TP, NaOH–P, and IP. For the slightly polluted sediments, the bioavailable P can only be evaluated by different chemical extractable methods.

Evaluation of phosphorus bioavailability in sediments of three contrasting lakes in China and the UK

The bioavailability of phosphorus (P) in sediments from West Lake and Lake Tai (China) and Lough Erne (Northern Ireland) was evaluated using total P (TP), water soluble P (WSP), readily desorbable P (RDP), algal available P (AAP) and Olsen-P. The results indicated that the TP content, the amounts of phosphorus extracted by each method and their proportions to TP varied widely between sediments of the three lakes. TP and chemical extractable phosphorus in the sediments of Lough Erne were considerably higher than those of the two lakes in China. Although TP in the West Lake sediments was similar to that of Lake Tai, the extractable phosphorus data suggested that the bioavailability of P in West Lake sediments was higher than that in sediments from Lake Tai. Nevertheless, the rank order of extraction efficiency was the same in all lakes and the amount extracted was in the sequence AAP>Olsen-P>WSP>RDP. There was a good correlation between extracted and TP in all the methods examined.

Bio-availability of phosphorus in sediments of the western Dutch Wadden Sea

Bio-availability of phosphorus in sediments of the western Dutch Wadden Sea