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The reproductive ecology of two eastern Pacific zooxanthellate coral species was examined as part of a continuing series of studies relating bleaching/mortality events caused by the El Niño–Southern Oscillation disturbance, and is described for study sites in Costa Rica, Panamá, and the Galápagos Islands (Ecuador). This study deals with the sibling agariciid species Pavona varians and Pavona sp.a over a 13?yr period (1985 to 1997). Both Pavona species are broadcast-spawners with some gonochoric, but mostly sequential hermaphroditic colonies. Minimum colony sizes (and ages) at first reproduction were 5?cm (5?yr) and 3?cm (2 to 3?yr), respectively, in P. varians and Pavona sp.a. In the Panamá and Galápagos populations, gonochoric colonies spawn eggs or sperm at least monthly. Six fecundity attributes were not significantly different in the two species, but the eggs of P. varians are white to beige and positively buoyant, and those of Pavona sp.a are dark green and neutrally to negatively buoyant. Eggs of both species lack zooxanthellae. Both species are reproductively active year-round, with maximum activity in the dry season in the nonupwelling Gulf of Chiriquí, and in the wet season in the upwelling Gulf of Panamá. Spawning is predominantly during full moon, and possibly also at new moon at most study sites. Spawning in P. varians and Pavona sp.a is 12?h out of phase, with the former species spawning ~1?h before sunrise and the latter about 1?h after sunset. The fecundity of Pavona spp. at Caño and the Galápagos Islands was much greater (19?900 to 27?900 eggs cm?2?yr?1) than at all Panamá sites (14?800 to 19?800 eggs cm?2?yr?1). Intraspecific crosses in both species resulted in swimming planula larvae after 25 to 36?h. Recruitment of P. varians was highest in Panamá, moderate in Costa Rica, and nil in the Galápagos Islands, matching, respectively, the contributions of P. varians to the pre-1982/1983 El Niño coral-population abundances in these areas. Recruitment success of P. varians at Uva Island was significantly related to maximum monthly positive sea surface-temperature (SST) anomalies that occurred in the year preceding recruitment over the period 1982 to 1996; recruitment failed when SST anomalies exceeded 1.6 to 1.9?C° during the severe ENSO events of 1982/1983 and 1997/1998. 相似文献
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Emission of volatile organic sulfur compounds (VOSCs) during aerobic decomposition of food wastes 总被引:1,自引:0,他引:1
Ting Wu Xinming Wang Dejun Li Zhigang Yi 《Atmospheric environment (Oxford, England : 1994)》2010,44(39):5065-5071
Food wastes collected from typical urban residential communities were investigated for the emission of volatile organic sulfur compounds (VOSCs) during laboratory-controlled aerobic decomposition in an incubator for a period of 41 days. Emission of VOSCs from the food wastes totaled 409.9 mg kg?1 (dry weight), and dimethyl disulfide (DMDS), dimethyl sulfide (DMS), methyl 2-propenyl disulfide, carbonyl sulfide and methyl 1-propenyl sulfide were the five most abundant VOSCs, with shares of 75.5%, 13.5%, 4.8%, 2.2% and 1.3% in total 15 VOSCs released, respectively. The emission fluxes of major VOSCs were very low at the beginning (day 0). They peaked at days 2–4 and then decreased sharply until they leveled off after 10 days of incubation. For most VOSCs, over 95% of their emission occurred in the first 10 days. The time series of VOSC emission fluxes, as well as their significant correlation with internal food waste temperature (p < 0.05) during incubation, suggested that production of VOSC species was induced mainly by microbial activities during the aerobic decomposition instead of as inherited. Released VOSCs accounted for 5.3% of sulfur content in the food wastes, implying that during aerobic decomposition considerable portion of sulfur in food wastes would be released into the atmosphere as VOSCs, primarily as DMDS, which is very short-lived in the atmosphere and thus usually less considered in the sources and sinks of reduced sulfur gases. 相似文献
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采用高温好氧/中温厌氧两级污泥消化(AerTAnM)工艺处理城市污水污泥,通过考察挥发性悬浮固体(VSS)去除率和沼气产量,研究了进泥浓度、中温相污泥投配率、搅拌速度、高温相污泥停留时间(SRT)对AerTAnM工艺消化效率的影响。结果表明,AerTAnM工艺的最佳运行条件:进泥总悬浮固体(TSS)为4.2%(质量分数),VSS为26.59g/L,高温相SRT为2.0d,中温相污泥投配率为8%,搅拌速度为100r/min。在该最佳运行条件下,系统稳定运行阶段出泥VSS去除率达45%以上,沼气产量达到1.06L/g(以VSS计),粪大肠杆菌和蛔虫卵的杀灭率达到95%以上,出泥可达《城镇污水处理厂污染物排放标准》(GB18918—2002)控制要求。 相似文献
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