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Rivers receiving acid mine drainage (AMD) are frequently depauperate in fish and impacts may extend long distances downstream. AMD inputs may form chemical barriers for migratory species and isolate fish in unimpacted headwaters. We investigated the response of a diadromous fish, kōaro (Galaxias brevipinnis), to remediation of an AMD tributary in a 5th order river in New Zealand. A 2005 survey indicated limited recruitment of kōaro in the river likely due to the chemical barrier of AMD. By 2010, water treatment in the contaminated tributary had raised pH from a median value of 4.3 to 6 and reduced metals in the lower river, notably aluminium from a median of 2.48 to 0.41?mg/L. In 2012, kōaro density had increased by an order of magnitude relative to 2005. Furthermore, a greater proportion of juvenile fish were present. These results indicate that large-scale remediation of discharges can reverse the impacts of AMD on fish migration. 相似文献
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Lucy A. Muir Jason Dunlop Andrew Moore 《Proceedings of the Geologists' Association. Geologists' Association》2012,123(1):165-169
Rochdale Museum Service holds a large collection of fossils from the important Carboniferous site of Sparth Bottoms (Lancashire, UK; Middle Coal Measures). Several of these are type specimens donated by Harold Howard in 1939. These objects were stored in the museum basement for several decades, and were thought to have been lost. The types are the holotype of the scorpion Eobuthus holti Pocock, 1911 and the holotype of the crustacean Anthrapalaemon grossarti var. holti Woodward, 1911a. These species were not named after Howard, because the describers thought that Fred Holt was the rightful collector. The holotype of the myriapod Euphoberia woodwardi Baldwin, 1911 (put into synonymy with Palaeosoma robustum Baldwin, 1911) is known to have originally been in the collection, but was not located in a recent survey. 相似文献
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R. J. McLure M. J. Jarvis T. A. Targett J. S. Dunlop P. N. Best 《Monthly notices of the Royal Astronomical Society》2006,368(3):1395-1403
We present the results of a study which uses the 3C RR sample of radio-loud active galactic nuclei to investigate the evolution of the black hole:spheroid mass ratio in the most massive early-type galaxies from 0 < z < 2 . Radio-loud unification is exploited to obtain virial (linewidth) black hole mass estimates from the 3C RR quasars, and stellar mass estimates from the 3C RR radio galaxies, thereby providing black hole and stellar mass estimates for a single population of early-type galaxies. At low redshift ( z ≲ 1) , the 3C RR sample is consistent with a black hole:spheroid mass ratio of M bh / M sph ≃ 0.002 , in good agreement with that observed locally for quiescent galaxies of similar stellar mass ( M sph ≃ 5 × 1011 M⊙ ) . However, over the redshift interval 0 < z < 2 the 3C RR black hole:spheroid mass ratio is found to evolve as M bh / M sph ∝ (1 + z )2.07±0.76 , reaching M bh / M sph ≃ 0.008 by redshift z ≃ 2 . This evolution is found to be inconsistent with the local black hole:spheroid mass ratio remaining constant at a moderately significant level (98 per cent). If confirmed, the detection of evolution in the 3C RR black hole:spheroid mass ratio further strengthens the evidence that, at least for massive early-type galaxies, the growth of the central supermassive black hole may be completed before that of the host spheroid. 相似文献
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