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AbstractAlthough the wider Eastern Tropical Pacific has been systematically surveyed during summer/fall, relatively little effort has focused on shelf and slope waters of Nicaragua and Costa Rica. Such data are useful for establishing baseline information and assessing potential changes in cetacean occurrence and distribution relative to natural (e.g., El Niño-Southern Oscillation, climate change) and anthropogenic factors. A visualacoustic survey for cetaceans occurred as part of a monitoring and mitigation program during an academic geophysical seismic study off Nicaragua and Costa Rica, during November-December 2004. Approximately 2 067 cetaceans representing at least seven species were seen in 75 groups during 373 h (3 416 km) of daytime observations from the seismic research vessel (R/V) Maurice Ewing. The humpback whale (Megaptera novaeangliae) and the pantropical spotted dolphin (Stenella attenuata) were the most frequently sighted species (30 % of all groups sighted); both were seen in shelf waters < 100 m deep and in slope waters. The bottlenose dolphin (Tursiops truncatus; 10 % of sightings) was the third most frequently sighted species and was only seen in water > 100 m deep. In addition, sightings were made of spinner dolphins (S. longirostris), short-beaked common dolphins (Delphinus delphis), Risso's dolphins (Grampus griseus), short-finned pilot whales (Globicephala macrorhynchus), and unidentified dolphins and whales. Unconfirmed sightings of a minke whale (Balaenoptera acutorostrata) and a pod of false killer whales (Pseudorca crassidens) were also recorded. An additional six groups of dolphins (50 % confirmed to species, all pantropical spotted dolphins) were made during 187 h (1 549 km) of observation effort during darkness, two of which were detected within 30 m of the vessel bow using a night vision device. A total of 217 cetacean detections occurred during 633 h of passive acoustic monitoring. A small concentration of 12 humpback whales was seen in eight groups, and two humpbacks were recorded singing in the Gulf of Fonseca on 9 December 2004. To our knowledge, such concentrations of humpback whales, particularly singing humpbacks, have not been previously reported in this specific area. In addition, a humpback mother-calf pair, likely from the Northern Hemisphere population, was seen off Northern Costa Rica on 25 November 2004. Although cetacean sighting rates were significantly different during seismic and non-seismic periods even when corrected for differential detection probability related to sea conditions, our survey results do provide information to address previous data gaps on cetacean occurrence in shelf and slope waters off the Pacific coast of Central America during late fall.
ResumenAunque el ancho Pacífico Tropical Oriental ha sido sistemáticamente sondeado durante el verano/otoño, relativamente poco esfuerzo se ha aplicado tanto en aguas de la plataforma continental como el talud de Nicaragua y Costa Rica. Tales datos son útiles para establecer una información base y evaluar los cambios potenciales en la presencia y distribución relacionada tanto a factores naturales (ej., fenómeno de El Niño, cambio climático) como a factores antropogénicos. Un sondeo visual y acústico de cetáceos fue realizado como parte de un programa de monitoreo y mitigación durante un estudio académico de geofísica (sísmica) en las afueras de las costas de Nicaragua y Costa Rica durante Noviembre y Diciembre 2004. Aproximadamente 2 067 cetáceos representantes de al menos siete especies fueron avistados en 75 grupos durante 373 h (3 416 km) de observación diurna desde el buque de prospección sísmica (R/V) Maurice Ewing. La ballena jorobada (Megaptera novaeangliae) y el delfín manchado pantropical (Stenella attenuata) fueron las especies más frecuentemente avistadas (30 % de todos los grupos avistados); ambas fueron avistadas tanto en aguas de la plataforma continental < 100 m de profundidad como en aguas del talud. El delfín nariz de botella (Tursiops truncatus; con un 10 % de los avistamientos) fue la tercera especie más avistada, solamente visto en aguas > 100 m de profundidad. Adicionalmente, se registraron avistamientos de delfines acróbatas (S. longirostris), delfines comunes de hocico corto (Delphinus delphis), calderones grises (Grampus griseus), ballenas piloto de aleta corta (Globicephala macrorhynchus) además de ballenas y delfines no identificados. También se registró un avistamiento no confirmado de una ballena de minke (Balaenoptera acutorostrata) y uno de un grupo de falsas orcas (Pseudorca crassidens). Un adicional de seis avistamientos de delfines (confirmándose en un 50 % de ellos para la especie de delfín manchado pantropical) se observaron durante 187 h (1 549 km) de esfuerzo durante lapsos de oscuridad, dos de los cuales se detectaron a 30 m de la proa de la embarcación utilizando dispositivos de visión nocturna. Un total de 217 detecciones de cetáceos ocurrieron durante 633 h de monitoreo acústico pasivo. Una pequeña concentración de 12 ballenas jorobadas fue avistada en ocho grupos, y dos jorobadas fueron registradas cantando en el Golfo de Fonseca el 9 de Diciembre 2004. Para nuestro conocimiento, tal concentración de ballenas jorobadas, particularmente jorobadas cantando, no han sido reportadas previamente en esta área específica. Adicionalmente, una pareja de jorobadas madre-cría, probablemente de la población del Hemisferio Norte, fue avistada en las afueras de la costa de Costa Rica el 25 de Noviembre 2004. A pesar de que las tasas de avistamiento fueron significativamente distintas durante los periodos sísmicos y no sísmicos, incluso siendo corregidos según la probabilidad de detecciones relacionadas a las condiciones del mar, nuestro sondeo provee información que cubre vacíos previos de datos en la presencia de cetáceos en las aguas tanto de la plataforma como del talud continental fuera de las costas del Pacífico de América Central durante el otoño tardío.
RESUMEN
Aims: To determine the bacteriological quality and geophysical abiotic components including mineral elements of public drinking water sources in Akungba-Akoko community located in South West Nigeria. Study Design: Water and soil samples were collected from selected ground water (e.g., well, borehole) and surface water (e.g., streams) in 20 various locations of Akungba-Akoko community. Similarly, Geographical positioning system (GPS) of the sampling site was determined. Methodology: Total bacteria and coliform content of water samples were enumerated using the pour plate technique. The physico-chemical parameters such as pH, turbidity and temperature and mineral elements constituents were determined. Total bacterial count, phosphorus (P) and copper (Cu) were also determined in the soil samples. Results: The total bacterial count ranged from as low as 1.0 x 102 cfu/mL in GLAS site to 1.22 x 106 cfu/mL in sample site GLA9, while the coliforms count ranged from 5.0 x 101 cfu/mL in well water of sample site GLG1 to 36 x 104 cfu/mL and 3.8 x 105 cfu/mL in sample site GL9 and GL7 respectively. As for soil sources, the total heterotrophic bacterial count range was from 1.8 x105 cfu/g to 8.7 x105 cfu/g. Total hardness of the water sources ranged from 4.46 ppm in sample site GLA2 to 216.86 ppm in well water (GLWS 6) in Akungba. High levels of lead in some areas as in Araromi pond zone (GLCW16) and Well water 2nd Market (GLBWS 6) among others, exceeded the maximum permissible level of 0.10 mg/L. The pH of water sources range from pH 5.52 to pH 7.91 while temperature ranges from 23ºC to 28ºC. Conclusion: This study shows that many sources of public drinking water supply in Akungba-Akoko are microbiologically substandard with possible infiltration of some chemical contaminants. Hence, routine monitoring and protection of the water resources is necessary in this community to improve the quality of drinking water and avoid possible associated health risks.
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Rudolf Barth participou de duas expedições científicas à ilha da Trindade, Brasil, em 1957 e 1959. Para comentar seus relatórios, este artigo narra a história dessa ilha, assim como o contexto nacional e mundial nos anos 1950. Barth alertou sobre as ameaças ambientais à ilha da Trindade, diagnosticou problemas e propôs soluções. Descreveu espécies endêmicas e invasoras. Consciente dos limites impostos por sua curta estada na ilha, defendeu a realização de investigações em épocas diversas do ano. Práticas científicas contemporâneas corroboram várias de suas análises. Desde fins dos anos 1950, a ilha da Trindade tem sido utilizada não só como metáfora dos desafios ambientais globais, mas também como 'laboratório' de ações conservacionistas.
Rudolf Barth took part in two scientific expeditions to Trindade Island, Brazil, in 1957 and 1959. As a backdrop to comments about his reports, the article tells the island's history and describes the national and world context in the 1950s. Barth warned about the environmental threats to Trindade, diagnosed its problems, and proposed solutions. He described endemic and invasive species. Aware that the brevity of his stay constrained his findings, he advocated further research at differing times of the year. Contemporary scientific practices corroborate a number of his analyses. Since the late 1950s, Trindade has served not only as a metaphor for global environmental challenges but also as a laboratory for conservationist measures.