Continued post-bleaching decline and changed benthic community of a Kenyan coral reef

During the global coral bleaching event of 1997/1998 Kenyan reefs experienced between 50% and 90% coral mortality, with coral cover at Malindi being reduced from 35–45% (pre-bleaching) to 10–20%. Even before this event there was concern that these reefs were being impacted by increased sediment loads from the nearby Sabaki River. Here we report that since 1998 coral cover has declined yet further with, in 2004, means of 5.1% being recorded at North Reef (within the non-fished Malindi Marine National Park) and 2.3% on Leopard Reef (within the fished Marine Reserve). Prior to bleaching 55 coral genera were recorded from the area, currently we find only 23. Meanwhile algal cover, especially the calcareous green alga Halimeda, has increased, and on Leopard Reef is twice that on North Reef. Taken with the evidence of previous studies, these data suggest a combined impact of coral bleaching with sedimentation and fishing.     

地震灾害死亡人口快速评估方法对比研究

中国是世界上地震活动最为频繁的国家之一,属于地震多发区。在收集分析国内外关于地震灾害死亡人口评估模型的基础上,选取10种模型以2000年以来中国典型地震灾害为案例验证其适用性。结果表明：① 对于5.7级（含）以下地震,10种模型的评估结果基本都在合理范围内,可采用各评估结果的区间值来支撑应急决策;5.7~6.6级（含）地震,10种评估方法得到的结果表现出不同程度的偏差,可采用多数评估结果指向的死亡人口数量级来支撑应急决策;6.6级以上地震,则只能采用有特定适用范围的基于结构易损性的评估结果来支撑应急决策,且也存在较大的不确定性。② 从地震灾害人员伤亡动态评估方法、地震—地质灾害死亡人口快速评估方法和快速评估软件系统方面进行了相关讨论。此研究可为地震灾害死亡人口快速评估模型的改进与发展提供借鉴。     

Kelp Gulls (Larus dominicanus) killed and injured by discarded monofilament lines at a marine recreational fishery in northern Patagonia

Among marine debris, monofilament fishing lines often result in negative impacts on marine organisms. We characterized marine debris and incidence of lost and discarded monofilament lines along beaches used by recreational fishers, and report the impact of lines on Kelp Gulls (Larus dominicanus) at the Bahía San Blas protected area, site of one of the main shore-based recreational fisheries of the southwestern Atlantic. Over 55% of the marine debris recorded originated from recreational fishing activities. Balls of tangled monofilament lines were found at a rate of 40.5 items per km. A total of 27 adult Kelp Gulls were found entangled with monofilament. All individuals were tangled to vegetation within colony boundaries. Four of the gulls had a monofilament line protruding from the bill, showing that they may be also killed when trying to obtain bait. Our results indicate that lost or discarded monofilament lines in the Bahía San Blas recreational fishing area result in undesired impacts on coastal wildlife.     

Hydrodynamic control of phytoplankton in low salinity waters of the James River estuary,Virginia, U.S.A.

Autotrophic biomass and productivity as well as nutrient distributions and phytoplankton cell populations in the James River estuary, Virginia, were quantified both spatially and temporally over a 17-month period. Emphasis was placed on the very low salinity region of the estuary in order to gain information on the fate of freshwater phytoplankters. Differing amounts of freshwater plant biomass are advected into the estuary as living material, DOC or POC and the demonstrated variability of this input must play an important role in marine biogeochemical cycling.Late summer and fall maxima in both chlorophyll a and the photosynthetic production of particulate organic carbon in very low salinity regions were inversely correlated with river discharge.During periods of low river discharge greater than 50% of the chlorophyll a biomass measured at 0‰ disappeared within a narrow range of salinity (0–2‰). Cell enumeration data suggest that species introduced from the freshwater end-member tend to comprise the bulk of the biomass removed. Confounding factors, which may contribute to the regulation of both the abundance and species of phytoplankters mid-river, include the flocculation of colloidal material with phytoplankton cells, the presence of the turbidity maximum and the growth of endemic phytoplankton populations.An inverse relationship exists between the phytoplankton abundance in very low salinity waters and the abundance of biomass measured in the lower portion of the river (estuary). Thus, autotrophic production in the fresh and very low salinity areas may indirectly regulate the onset on the spring bloom in the estuary by controlling the amount of nutrients available.     

A mass mortality of subtropical intertidal populations of the sea urchin Paracentrotus lividus: analysis of potential links with environmental conditions

An outbreak of bald sea urchin disease was detected affecting intertidal populations of the edible temperate species Paracentrotus lividus at its southernmost geographical limit. The mortality event was detected in three sites (Güímar, Palmar and Alcalá) off Tenerife, Canary Islands (Northeastern Atlantic), in October 2003, coinciding with the highest sea surface temperatures (SST) and the lowest wave heights of the year. The prevalence of infection reached 100% but did not affect equally all studied sites or the different size classes. The disease was more prevalent in large sea urchins (>40 mm). The prevalence appeared to be positively correlated with the environmental variable SST and negatively correlated with wave height. In October 2004, only two infected urchins were found (prevalence 1%) at one of the studied sites. However, during 2004 no such extreme values of temperature and wave height were observed. We conclude that high SSTs and low wave heights such as those observed during 2003 are conditions that may trigger outbreaks of urchin disease.