Forty Years of Winter: Cetaceans Observed During the Southbound Migration of Gray Whales, Eschrichtius robustus, Near Granite Canyon, Central California

From December to February in most years from 1967 to 2007, observers counted gray whales, Eschrichtius robustus, from shore sites south of Carmel in central California. In addition to gray whales, other cetacean species were also recorded. These observations were summarized and compared among survey platforms and to ocean conditions. Eleven cetacean species were identified including eight odontocete species (killer whale, Orcinus orca; Pacific white-sided dolphin, Lagenorhynchus obliquidens; common dolphin, Delphinus spp.; bottlenose dolphin, Tursiops truncatus, northern right whale dolphin, Lissodelphis borealis; Risso’s dolphin, Grampus griseus; Dall’s porpoise, Phocoenoides dalli; and harbor porpoise, Phocoena phocoena) and three mysticete species (humpback whale, Megaptera novaeangliae; minke whale, Balaenoptera acutorostrata; and blue whale, Balaenoptera musculus). As expected, the detection of certain species among survey platforms (shore-based census watches, 25-power “Big Eye” binocular watches, and aerial surveys) was limited by species surfacing behavior and/or bathymetric preference. Comparisons among the shore-based census efforts showed a significant difference in sightings rates from 1967–84 (n = 14, mean = 0.11, SD = 0.11) to 1985–2007 (n = 11, mean = 1.48, SD = 0.47; t-Test: p < 0.001, df = 23). The warm period observed during the 1990’s may partially explain the increase in sighting rates and diversity of species observed at the census site compared to the much cooler temperatures of the 1970’s.

Potencial de geração de metano em aterros sanitários através dos modelos IPCC, USEPA e Scholl Canyon estudo de caso do aterro sanitário de Moskogen, Kalmar, Suécia.

A utilização do metano (CH4) presente no biogás gerado através da degradação anaeróbica de resíduos orgânicos depositados em aterros sanitários como fonte de energia é uma tecnologia em expansão, principalmente nos países em desenvolvimento. Para assegurar um melhor aproveitamento do CH4 e a viabilidade econômica do projeto de exploração energética é necessário que estes empreendimentos avaliem sua capacidade de produzir este gás com o passar dos anos, mesmo após o encerramento da deposição de resíduos. O potencial de geração é comumente estimado a partir de modelos cinéticos de primeira ordem propostos por conceituadas instituições, entretanto, estudos recentes apontam alto grau de incerteza e diferenças relevantes entre os resultados obtidos com cada metodologia. Este trabalho tem por objetivo analisar a variação dos resultados das estimativas de emissão de metano dos modelos recomendados pela USEPA, Banco Mundial (Scholl Canyon) e IPCC utilizando tanto dados e informações disponibilizadas do aterro sanitário Moskogen, localizado em Kalmar, Suécia, que foi operado entre 1977 e 2008. Além de estimar a capacidade de geração de CH4, objetiva-se identificar qual o modelo cujas estimativas mais se aproximam dos dados de biogás efetivamente medidos e quanto gás ainda pode ser extraído do aterro. O estudo ainda avaliou como valores diferentes para os parâmetros principais dos modelos afetam a estimativa de geração final. O modelo IPCC mostrou-se o mais confiável dentre os analisados, estimando que o aterro Moskogen produza mais de 102 milhões de m de CH4 entre 1977 e 2100, sendo 39,384 milhões passíveis de extração de 2012 a 2100. Os demais modelos apresentaram premissas inadequadas com a realidade do aterro sanitário estudado. Contudo, mesmo com a superioridade do modelo proposto pelo IPCC, maiores estudos são necessários no local, que levantem outras informações de campo como a vazão passiva de gás pela camada de cobertura do aterro e uma melhor estimativa do percentual de material orgânico biodegradável presente em cada fração de resíduos depositada em Moskogen.

Changes in frost frequency and desert vegetation assemblages in Grand Canyon, Arizona

The effect of decreasing frost frequency on desert vegetation was documented in Grand Canyon by replication of historical photographs. Although views by numerous photographers of Grand Canyon have been examined, 400 Robert Brewster Stanton and Franklin A. Nims views taken in the winter of 1889-1890 provide the best information on recent plant distribution. In Grand Canyon, where grazing is limited by the rugged topography, vegetation dynamics are controlled by climate and by demographic processes such as seed productivity, recruitment, longevity and mortality. The replicated photographs show distribution and abundance of several species were limited by severe frost before 1889. Two of these, brittlebush (Encelia farinosa) and barrel cactus (Ferocactus cylindraceus), have clearly expanded their ranges up-canyon and have increased their densities at sites where they were present in 1890. In 1890, brittlebush was present in warm microhabitats that provided refugia from frost damage. Views showing desert vegetation in 1923 indicate that Encelia expanded rapidly to near its current distribution between 1890 and 1923, whereas the expansion of Ferocactus occurred more slowly. The higher frequency of frost was probably related to an anomalous increase in winter storms between 1878 (and possibly 1862) and 1891 in the southwestern United States.

Movements of bocaccio (Sebastes paucispinis) and greenspotted (S. chlorostictus) rockfishes in a Monterey submarine canyon: implications for the design of marine reserves

In August and September of 1997 and 1998, we used SCUBA techniques to surgically implant Vemco V16 series acoustic transmitters in 6 greenspotted rockfish (Sebastes chlorostictus) and 16 bocaccio (S. paucispinis) on the flank of Soquel Canyon in Monterey Bay, California. Fish were captured at depths of 100–200 m and reeled up to a depth of approximately 20 m, where a team of SCUBA divers anesthetized and surgically implanted acoustic transmitters in them. Tagged fish were released on the seafloor at the location of catch. An array of recording receivers on the seafloor enabled the tracking of horizontal and vertical fish movements for a three-month period. Greenspotted rockfish tagged in 1997 exhibited almost no vertical movement and showed limited horizontal movement. Two of these tagged fish spent more than 90% of the time in a 0.58-km2 area. Three other tagged greenspotted rockfish spent more than 60% of the time in a 1.6-km2 area but displayed frequent horizontal movements of at least 3 km. Bocaccio exhibited somewhat greater movements. Of the 16 bocaccio tagged in 1998, 10 spent less than 10% of the time in the approximately 12-km2 study area. One fish stayed in the study area for about 50% of the study time. Signals from the remaining 5 fish were recorded in the study area the entire time. Bocaccio frequently moved vertically 10–20 m and occasionally displayed vertical movements of 100 m or greater.

Urban canyon influence on building natural ventilation

The natural ventilation of a building, flanked by others forming urban canyons and driven by the combined forces of wind and thermal buoyancy, has been studied experimentally at small scale. The aim was to improve our understanding of the effect of the urban canyon geometry on passive building ventilation. The steady ventilation of an isolated building was observed to change dramatically, both in terms of the thermal stratification and airflow rate, when placed within the confines of urban canyons. The ventilation flows and internal stratifications observed at small scale are presented for a range of canyon widths (building densities) and wind speeds. Two typical opening arrangements are considered. Flanking an otherwise isolated building with others of similar geometry as in a typical urban canyon was shown to reverse the effect of wind on the thermally-driven ventilation. As a consequence, neglecting the surrounding geometry when designing naturally-ventilated buildings may result in poor ventilation. Further implications are discussed.

墨西哥湾Alaminos Canyon、Bush Hill冷泉碳酸盐岩有机地球化学与沉积环境

本文通过对墨西哥湾Bush Hill 的5个冷泉碳酸盐岩样品和Alaminos Canyon 的1个冷泉碳酸盐岩样品的总有机质含量、可溶有机质含量、饱和烃、芳烃、脂肪酸、δ13C组成分布特征和部分地球化学参数的研究，探讨了冷泉碳酸盐岩中有机质来源、成熟度和沉积环境。 Bush Hill的冷泉碳酸盐岩样品的总有机碳为0.78-9.02%，可溶有机质含量5.77-65.06mg/g。总有机碳达9.02%的GC-B样品高碳数正构烷烃奇偶优势明显，存在荧蒽、芘和苝系列化合物，表明该样品有陆源物质的输入，并明显受深部渗漏原油的影响，其中烷烃的δ13C为-27.64～-32.36‰，正构脂肪酸δ13C为-26.52～-39.99‰，与现代菌藻类及下伏油气藏的δ13C值（-27～-31‰）相似，表明样品中的有机质主体可能来源于深部油气藏。其余4个Bush Hill冷泉碳酸盐岩样品和1个Alaminos Canyon冷泉碳酸盐岩样品正构烷烃的低碳优势明显，而奇偶优势不明显，低碳数分布的环己烷和长链烷基苯，以及三芳甾烷和甲基三芳甾烷的存在，推断这些样品的母质以菌藻类来源为主。 所有分析样品的甾烷成熟度参数C29ββ/(ββ+αα)为0.28-0.40，C2920S/(20S + 20R)为0.42-0.61、及C20-C21三芳孕甾烷TA(Ⅰ)/C26-C28三芳甾烷TA(Ⅱ)为0.49都说明样品的有机质成熟度较低,。 AC深水区AC-E样品UCM隆起不明显，Bush Hill浅水区样品（GC-B、GC-D、GC-F、GC-G，GC-H）UCM隆起均十分明显，这种隆起的形成是因为正烷烃、甚至五环三萜烷遭受生物降解。被微生物降解的正构烷烃与未被降解的环烷烃和支链烷烃等形成不能被溶解的复杂混合物（UCM）。因此，UCM隆起通常被认为是有机质遭受生物降解最直接的证据。深水区AC-E和Bush Hill浅水区GC-F样品中芴、氧芴和硫芴之间的丰度关系为硫芴﹥芴﹥氧芴，表明其为弱氧化-弱还原的沉积环境。具有较负碳同位素组成（-63.95‰ ~ -50.48‰）的异构/反异构脂肪酸是硫酸盐还原细菌的典型生物标志化合物，进一步证实冷泉碳酸盐岩的形成与甲烷缺氧氧化作用有关。 关键词：墨西哥湾 冷泉碳酸盐岩 有机质组成分布 单体烃碳同位素 沉积环境

'Torrey Canyon' pollution and marine life. A report by the Plymouth Laboratory of the Marine Biological Association of the United Kingdom

This report describes the step-by-step development the Marine Biological Association's 10 week survey of the effects of the Torrey Canyon oil spill and discusses the results of field observations and laboratory experiments. It also outlines methods developed for predicting and plotting the movement of oil at sea.