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Fast and easy method for seagrass monitoring: Application of acoustic telemetry to precision mapping of Posidonia oceanica beds
2011
Descamp, Pierre | Holon, Florian | Ballesta, Laurent | Guilbert, Antonin | Guillot, Marie | Boissery, Pierre | Raimondino, Valérie | Deter, Julie
Posidonia oceanica is an endemic seagrass from the Mediterranean Sea. It is an indicator of water quality and of the ecological state of coastal ecosystems. The aim of this paper is to test acoustic telemetry for monitoring the position of P. oceanica meadow limits with varied types. After evaluating the accuracy of the system, we present results from a spatiotemporal survey of P. oceanica meadows on nine sites located on the French coast. The method has been demonstrated to be highly efficient for high precision underwater mapping regardless of meadow type, with 1cm accuracy for a distance of 40m between the base and the pointer. A temporal survey led at Cerbere–Banyuls shows a weak global progression of 4m² (progression of 26m² - regression of 22m²) between 2006 and 2010. Finally, we discuss the cost and efficiency of this method, and wether it should be generalized for further studies.
显示更多 [+] 显示较少 [-]Level and speciation of nickel in some forages in relation to spatial and temporal fluctuations
2020
Bashir, Humayun | Kafīl, Aḥmad | K̲h̲ān̲, Ẓafar Iqbāl
The present experimental work was conducted at different sites of district Bhakkar, a semiarid region of Pakistan, to assess whether the goats are suffering nickel deficiency or toxicity and what are the possible seasonal effects on the availability and translocation of nickel in food chain. A total of 27 forage and 320 goats according to four physiological stages [does (she goat), bucks (he goat), wether (castrated), juvenile (6 month)] were recruited for this study. To fulfill this objective, soil, forage, blood plasma, urine, and feces samples were collected in 4 seasons of the year at 2 sites and were analyzed by atomic absorption spectrophotometer for nickel concentration. Different indices BCF, EF, and PLI were also studied to check the metal transfer. The results showed that sites had significant (P < 0.05) effect on nickel concentration in soil, forage, and goats. On the other hand, season and site x season had nonsignificant (P > 0.05) effects on nickel level in soil and goats. The soil (0.68–0.71 mg kg⁻¹), forage (3.41–3.70 mg/kg), and blood (0.21–0.28 mg/l) level was lower than the permissible limits, while feces (0.57–1.34 mg/kg) and urine (0.35–1.32 mg/l) had enough concentration of nickel. Sources showed significant (P < 0.05) effects on Ni level in all stages of goats. All stages of goats except Wether (castrated) showed low level of nickel in blood. Most fluctuations in nickel concentration were observed in (S1) summer (low) and spring (S4) (high) season as a whole, while overall site 2 had high level of nickel than site 1. Thus, nickel showed deficiency in soil, forage, as well as in all stages of goats except wether goats. Nickel containing mineral mixtures are essential for does (she goat), bucks (he goat), and juveniles (6 months old), so application of Ni containing fertilizers to the soil and forage of that region and supplementation of Ni mineral mixture for grazing ruminants should be done.
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