High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution.

Science.gov (United States)

Lecavalier, Benoit S; Fisher, David A; Milne, Glenn A; Vinther, Bo M; Tarasov, Lev; Huybrechts, Philippe; Lacelle, Denis; Main, Brittany; Zheng, James; Bourgeois, Jocelyne; Dyke, Arthur S

2017-06-06

We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ∼12,000 y (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Ellesmere Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4-5 °C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ∼3,000 y. Our results show that air temperatures in this region are now at their warmest in the past 6,800-7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads to an estimated ∼1 km of ice thinning in northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ∼25% increase in total Greenland ice sheet mass loss (∼1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland.

Decision analysis of mitigation and remediation of sedimentation within large wetland systems: a case study using Agassiz National Wildlife Refuge

Science.gov (United States)

Post van der Burg, Max; Jenni, Karen E.; Nieman, Timothy L.; Eash, Josh D.; Knutsen, Gregory A.

2014-01-01

Sedimentation has been identified as an important stressor across a range of wetland systems. The U.S. Fish and Wildlife Service has the responsibility of maintaining wetlands within its National Wildlife Refuge System for use by migratory waterbirds and other wildlife. Many of these wetlands could be negatively affected by accelerated rates of sedimentation, especially those located in agricultural parts of the landscape. In this report we document the results of a decision analysis project designed to help U.S. Fish and Wildlife Service staff at the Agassiz National Wildlife Refuge (herein referred to as the Refuge) determine a strategy for managing and mitigating the negative effects of sediment loading within Refuge wetlands. The Refuge’s largest wetland, Agassiz Pool, has accumulated so much sediment that it has become dominated by hybrid cattail (Typha × glauca), and the ability of the staff to control water levels in the Agassiz Pool has been substantially reduced. This project consisted of a workshop with Refuge staff, local and regional stakeholders, and several technical and scientific experts. At the workshop we established Refuge management and stakeholder objectives, a range of possible management strategies, and assessed the consequences of those strategies. After deliberating a range of actions, the staff chose to consider the following three strategies: (1) an inexpensive strategy, which largely focused on using outreach to reduce external sediment inputs to the Refuge; (2) the most expensive option, which built on the first option and relied on additional infrastructure changes to the Refuge to increase management capacity; and (3) a strategy that was less expensive than strategy 2 and relied mostly on existing infrastructure to improve management capacity. Despite the fact that our assessments were qualitative, Refuge staff decided they had enough information to select the third strategy. Following our qualitative assessment, we discussed

Assessing genotoxic effects in fish from a marine protected area influenced by former mining activities and other stressors

International Nuclear Information System (INIS)

Gusso-Choueri, Paloma Kachel; Choueri, Rodrigo Brasil; Santos, Gustavo Souza; Seraphim de Araújo, Giuliana; Feitosa Cruz, Ana Carolina

2016-01-01

The goal of the current study was to evaluate different genotoxicity tools in order to assess a marine protected area (MPA) affected by former mining activities and urban settlements. A catfish (Cathorops spixii) was analyzed for genotoxic effects at the (i) molecular and at the (ii) chromosomal levels. Through factor analysis, genotoxicity was found to be linked to levels of metals bioaccumulated and PAH metabolites in the bile. Micronucleus and nuclear alteration were less vulnerable to the effects of confounding factors in mildly contaminated areas since they were more frequently associated with bioaccumulated metals than the DNA analysis. The different genotoxicity responses allowed for the identification of sources of pollution in the MPA. This approach was important for detecting environmental risks related to genotoxic contaminants in a mildly contaminated MPA. -- Highlights: •We assessed genotoxicity and bioaccumulation in catfish from a marine protected area. •The area is under the influence of past mining activities and urban settlements. •Cellular level responses were highly associated with body burdens of metals and As. •Responses at the molecular level were less associated with body burdens. •Genotoxicity in different organs helped identify pollution sources in MPA.

Espíritos cheios de bichos: A fauna nas viagens de Louis Agassiz e Richard Francis Burton pelo Brasil oitocentista

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Janaina Zito Losada

2015-04-01

Full Text Available O Brasil do século XIX foi alvo de inúmeras viagens realizadas por cientistas estrangeiros. O objetivo deste artigo é analisar as impressões sobre a fauna brasileira presentes nos relatos das viagens realizadas pelo naturalista suíço Louis Agassiz, em 1865, e pelo explorador inglês Richard Francis Burton, em 1868. Destes relatos privilegiam-se as descrições do meio natural de diferentes regiões brasileiras e das particularidades da fauna silvestre por eles encontrada.

A microestrutura e o desenvolvimento dos órgãos genitais masculinos de preás (Galea spixii criados em cativeiro The microstructure and development of male genital organs of Spix's yellow-toothed cavy (Galea spixii bred in captivity

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Paulo R.S. Santos

2012-12-01

Full Text Available O preá do semiárido nordestino (Galea spixii é um roedor pertencente à família Caviidae. São encontrados nas regiões da Caatinga e do Cerrado Brasileiro e se reproduz ao longo do ano, apresentando um período de gestação de 48 dias e uma ninhada de 2 a 4 crias. O objetivo deste estudo foi caracterizar histologicamente os componentes estruturais dos órgãos genitais de preás machos relacionando com a evolução cronológica destes órgãos na espécie. Foram utilizados para análise animais ao nascimento e aos 15, 30, 45, 60, 75, 90, 105, 120 e aos 150 dias de idade. Fragmentos do epidídimo, ducto deferente, pênis e glândulas sexuais acessórias foram coletados, fixados e processados para descrição em microscopia de luz. O epidídimo apresentou epitélio colunar simples e em cada fase sexual notou-se diferença quanto ao tamanho do lúmen tubular e à presença de espermatozóides no lúmen aos 45 dias de idade. O epitélio do ducto deferente no preá mostrou-se pseudo-estratificado colunar com crescente presença de estereocilios com o avanço da idade. A glândula vesicular no preá apresentou uma mucosa com pregueamento variado, de acordo com a fase do desenvolvimento sexual. A próstata mostrou-se pouco desenvolvida, com lúmen pequeno nos preás ao nascimento e aos 15 dias de idade; aos 45 dias mostrou-se com um pregueamento do epitélio variável. Os órgãos genitais masculinos do preá passaram por transformações morfológicas no decorrer da idade e com o desenvolvimento sexual, isso colaborou para a determinação do início da fase da puberdade, que na espécie em estudo foi aos 45 dias de idade.The Spix's yellow-toothed cavy (Galea spixii from the Brazilian northeastern semi-arid is a rodent that does belong to the family Caviidae. They are found in regions of the Caatinga and Cerrado, and reproduces throughout the year, with a gestation period of 48 days and a litter of 2 to 4 pups. The aim of this study was to

Chemical, physical, and other data collected using meteorological sensors, secchi disk, and bottle casts from the A. AGASSIZ as part of the California Cooperative Fisheries Investigation (CALCOFI) project, from 10 November 1966 to 13 November 1966 (NODC Accession 8900083)

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National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, physical, and other data were collected from the A. AGASSIZ from November 10, 1966 to November 13, 1966. Data were collected using meteorological sensors,...

Temperature profile and other data collected using bottle and CTD casts from the A. AGASSIZ and other platforms from a world-wide distribution during the California Cooperative Fisheries Investigation (CALCOFI) project, 06 January 1969 to 27 July 1977 (NODC Accession 8000006)

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National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data, temperature, and other data were collected using CTD and bottle casts from A. AGASSIZ and other platforms in a world-wide distribution...

Temperature profile and other data collected using bottle and CTD casts from the A. AGASSIZ and other platforms from the Pacific Ocean during the California Cooperative Fisheries Investigation (CALCOFI) project, 1954-07-25 to 1966-12-19 (NODC Accession 6900651)

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National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data, temperature, and other data were collected using CTD and bottle casts from A. AGASSIZ and other platforms in the Pacific ocean from July...

Temperature profile and other data collected using bottle and CTD casts from the A. AGASSIZ and other platforms from the Coastal Waters of California during the California Cooperative Fisheries Investigation (CALCOFI) project, 10 July 1969 to 26 October 1988 (NODC Accession 9000096)

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National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data, temperature, and other data were collected using CTD and bottle casts from A. AGASSIZ and other platforms from the Coastal Waters of...

Temperature profile and other data collected using bottle and CTD casts from the A. AGASSIZ and other platforms from the Coastal Waters of California during the California Cooperative Fisheries Investigation (CALCOFI) project, 1965-01-06 to 1968-06-22 (NODC Accession 7300970)

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National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data, temperature, and other data were collected using CTD and bottle casts from A. AGASSIZ and other platforms in the Coastal Waters of...

Temperature profile and other data collected using bottle and CTD casts from the A. AGASSIZ and NOAA Ship DAVID STARR JORDAN from the Coastal Waters of California during the California Cooperative Fisheries Investigation (CALCOFI) project, 03 January 1972 to 16 November 1972 (NODC Accession 8600369)

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National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data, temperature, and other data were collected using CTD and bottle casts from A. AGASSIZ and other platforms from the Coastal Waters of...

Temperature profile and other data collected using bottle and CTD casts from the A. AGASSIZ and NOAA Ship DAVID STARR JORDAN from the Coastal Waters of California during the California Cooperative Fisheries Investigation (CALCOFI) project, 26 January 1974 to 13 November 1975 (NODC Accession 8600370)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data, temperature, and other data were collected using CTD and bottle casts from A. AGASSIZ and NOAA Ship DAVID STARR JORDAN from the Coastal...

Assessing pollution in marine protected areas: the role of a multi-biomarker and multi-organ approach.

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Gusso-Choueri, Paloma Kachel; Choueri, Rodrigo Brasil; de Araújo, Giuliana Seraphim; Cruz, Ana Carolina Feitosa; Stremel, Tatiana; Campos, Sandro; Abessa, Denis Moledo de Sousa; Ribeiro, Ciro Alberto Oliveira

2015-11-01

Marine protected areas (MPAs) are vulnerable to many pressures, including pollution. However, environmental quality monitoring in these areas traditionally relies on only water chemistry and microbiological parameters. The goal of the current study was to investigate the role of a set of biomarkers in different target organs (liver, kidney, and gills) of fish in order to assess the environmental quality of an MPA (MTs, GPx, GST, GSH, DNA damage, LPO, AChE, and condition index). Chemical analyses were also performed on liver and muscle tissues to evaluate metal body burdens, and PAHs were identified in bile. A demersal fish (Cathorops spixii) that is widely consumed by the local population was used as bioindicator species, and the results were integrated using multivariate analysis. The use of the biomarker approach allowed for the identification of both seasonal and spatial variations in pollution sources around the Environmental Protected Area of Cananéia-Iguape-Peruíbe (APA-CIP). Higher metal body burdens associated with biological responses were found in the sites under the influence of urban areas during the dry season, and they were found in the sites under the influence of the Ribeira de Iguape River (RIR) during the rainy season. The liver was found to be more responsive in terms of its antioxidant responses, whereas gills were found to be more responsive to biomarkers of effect. These results show that this set of biomarker analyses in different organs of fish is a useful tool for assessing chemical pollution in an MPA.

Nelson's big horn sheep (Ovis canadensis nelsoni) trample Agassiz's desert tortoise (Gopherus agassizii) burrow at a California wind energy facility

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Agha, Mickey; Delaney, David F.; Lovich, Jeffrey E.; Briggs, Jessica; Austin, Meaghan; Price, Steven J.

2015-01-01

Research on interactions between Agassiz's desert tortoises (Gopherus agassizii) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep (Ovis aries). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle (Bos taurus) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

The Agassiz's desert tortoise genome provides a resource for the conservation of a threatened species.

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Marc Tollis

Full Text Available Agassiz's desert tortoise (Gopherus agassizii is a long-lived species native to the Mojave Desert and is listed as threatened under the US Endangered Species Act. To aid conservation efforts for preserving the genetic diversity of this species, we generated a whole genome reference sequence with an annotation based on deep transcriptome sequences of adult skeletal muscle, lung, brain, and blood. The draft genome assembly for G. agassizii has a scaffold N50 length of 252 kbp and a total length of 2.4 Gbp. Genome annotation reveals 20,172 protein-coding genes in the G. agassizii assembly, and that gene structure is more similar to chicken than other turtles. We provide a series of comparative analyses demonstrating (1 that turtles are among the slowest-evolving genome-enabled reptiles, (2 amino acid changes in genes controlling desert tortoise traits such as shell development, longevity and osmoregulation, and (3 fixed variants across the Gopherus species complex in genes related to desert adaptations, including circadian rhythm and innate immune response. This G. agassizii genome reference and annotation is the first such resource for any tortoise, and will serve as a foundation for future analysis of the genetic basis of adaptations to the desert environment, allow for investigation into genomic factors affecting tortoise health, disease and longevity, and serve as a valuable resource for additional studies in this species complex.

Presencia de Trachemys Agassiz, 1857 (Testudines, Emydidae en el Pleistoceno tardío del centro de la Argentina

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Cabrera, Mario R.

2011-08-01

Full Text Available En este trabajo se describen restos del caparazón de una tortuga que constituyen el primer registro del género dulceacuícola Trachemys Agassiz, 1857 y de la familia Emydidae Rafinesque, 1815 en la provincia de Córdoba, y el hallazgo más occidental de ambos en la Argentina. Los materiales recuperados consisten en la placa proneural, las placas pleurales IV y VIII derechas y fragmentos de las placas pleurales III y IV izquierdas, epiplastron, hioplastron e hipoplastron derechos, más tres fragmentos indeterminables. Los restos provienendel Sitio El Silencio (30°53’20" S, 62°49’29" W, un yacimiento paleontológico de edad Pleistoceno tardío - Holoceno temprano, expuesto en la costa de la actual laguna Mar Chiquita, en un nivel de limo con intercalaciones de carbonato de calcio asignado a la Formación Tezanos Pinto, cuya depositación se produjo entre los 36.000 y 8.000 AP. El registro esrelacionado con un evento húmedo acontecido entre los 16.500 y 15.500 años AP, que pudo haber sido lo suficientemente marcado y sostenido como para posibilitar el ingreso deTrachemys (y otros taxones vertebrados durante el Pleistoceno a cercanías de la laguna Mar Chiquita, unos 220 km hacia el oeste de su distribución actual.

Multiple factors affect a population of Agassiz's desert tortoise (Gopherus agassizii) in the Northwestern Mojave Desert

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Berry, Kristin H.; Yee, Julie L.; Coble, Ashley A.; Perry, William M.; Shields, Timothy A.

2013-01-01

Numerous factors have contributed to declines in populations of the federally threatened Agassiz's Desert Tortoise (Gopherus agassizii) and continue to limit recovery. In 2010, we surveyed a low-density population on a military test facility in the northwestern Mojave Desert of California, USA, to evaluate population status and identify potential factors contributing to distribution and low densities. Estimated densities of live tortoises ranged spatially from 1.2/km2 to 15.1/km2. Although only one death of a breeding-age tortoise was recorded for the 4-yr period prior to the survey, remains of 16 juvenile and immature tortoises were found, and most showed signs of predation by Common Ravens (Corvus corax) and mammals. Predation may have limited recruitment of young tortoises into the adult size classes. To evaluate the relative importance of different types of impacts to tortoises, we developed predictive models for spatially explicit densities of tortoise sign and live tortoises using topography (i.e., slope), predators (Common Raven, signs of mammalian predators), and anthropogenic impacts (distances from paved road and denuded areas, density of ordnance fragments) as covariates. Models suggest that densities of tortoise sign increased with slope and signs of mammalian predators and decreased with Common Ravens, while also varying based on interaction effects involving these predictors as well as distances from paved roads, denuded areas, and ordnance. Similarly, densities of live tortoises varied by interaction effects among distances to denuded areas and paved roads, density of ordnance fragments, and slope. Thus multiple factors predict the densities and distribution of this population.

Linking fishery management and conservation in a tropical estuarine lagoon: biological and physical effects of an artisanal fishing gear

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Rueda, M.; Defeo, O.

2003-04-01

Information coming from fishery monitoring, surveys and experimental fishing with participation of fishers was employed to determine the impact of an artisanal gear, 'boliche', on the biodiversity of the Ciénaga Grande de Santa Marta (CGSM), an estuarine lagoon on the Caribbean coast of Colombia. Fishery monitoring (catch data) included landings before (1968 and 1978) and after (1994-1996) the introduction of the boliche in the CGSM (1985), whereas surveys were conducted seasonally during 1993-1994. Fishing experiments involved evaluating different mesh sizes and the short-term effect of physical disturbance by the boliche. Monitoring suggested potential trophic effects of this fishing gear: the catch of large, long-lived, carnivorous species declined after the introduction of the boliche in the CGSM, whereas catch rates of smaller, shorter-lived, and lower trophic level species increased. Surveys revealed that the boliche retained 41 species. The by-catch made up 62% of the total catch and the remaining 38% involved the three target species Eugerres plumieri, Mugil incilis and Cathorops spixii. Selectivity experiments showed that 2.5 in. stretched mesh size gill nets caught more species than the 3.0-in. mesh. The smaller mesh also increased the risk of a critical reduction in the spawning stock of target species (notably E. plumieri); a situation that could affect the fish community if mesh sizes lower than 2.5 in. were intensively used. Suspended particulate matter significantly increased after fishing activity, with higher resuspension on mud-shells and mud substrata, whereas dissolved oxygen showed no appreciable changes after fishing operations. Notwithstanding, the activity of the boliche would generate sediment resuspension between 382 and 470 t day -1, which could lead to potential cascade impacts on water quality. We propose a framework of redundancy in management measures in order to simultaneously reach management and conservation goals.

Phylogenetic and morphologic analyses of a coastal fish reveals a marine biogeographic break of terrestrial origin in the southern Caribbean.

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Ricardo Betancur-R

2010-07-01

Full Text Available Marine allopatric speciation involves interplay between intrinsic organismal properties and extrinsic factors. However, the relative contribution of each depends on the taxon under study and its geographic context. Utilizing sea catfishes in the Cathorops mapale species group, this study tests the hypothesis that both reproductive strategies conferring limited dispersal opportunities and an apparent geomorphologic barrier in the Southern Caribbean have promoted speciation in this group from a little studied area of the world.Mitochondrial gene sequences were obtained from representatives of the Cathorops mapale species group across its distributional range from Colombia to Venezuela. Morphometric and meristic analyses were also done to assess morphologic variation. Along a approximately 2000 km transect, two major lineages, Cathorops sp. and C. mapale, were identified by levels of genetic differentiation, phylogenetic reconstructions, and morphological analyses. The lineages are separated by approximately 150 km at the Santa Marta Massif (SMM in Colombia. The northward displacement of the SMM into the Caribbean in the early Pleistocene altered the geomorphology of the continental margin, ultimately disrupting the natural habitat of C. mapale. The estimated approximately 0.86 my divergence of the lineages from a common ancestor coincides with the timing of the SMM displacement at approximately 0.78 my.Results presented here support the hypothesis that organismal properties as well as extrinsic factors lead to diversification of the Cathorops mapale group along the northern coast of South America. While a lack of pelagic larval stages and ecological specialization are forces impacting this process, the identification of the SMM as contributing to allopatric speciation in marine organisms adds to the list of recognized barriers in the Caribbean. Comparative examination of additional Southern Caribbean taxa, particularly those with varying life

Time-series analysis for the episodic production and transport of methane from the Glacial Lake Agassiz peatlands, northern Minnesota. Final report

Energy Technology Data Exchange (ETDEWEB)

Siegel, D.I.

1998-01-01

The large peat basins of North America are an important reservoir in the global carbon cycle and a significant source of atmospheric methane. The authors investigated carbon cycling in the Glacial Lake Agassiz peatlands (GLAP) of Minnesota. Initially in 1990, they identified a dramatic change in the concentration of methane in the pore-waters of the raised bogs in the GLAP during an extreme drought. This methane dissipated when the drought broke in 1991 and the occurrence of deep methane is related to changes in the direction of groundwater flow in the peat column. The production of methane and its diffusive loss to the atmosphere was modeled and was about 10 times less than that measured directly in chambers at the land surface. It is clear from the reversals in hydraulic heat, changes in pore-water chemical composition over time, and paleostratigraphic markers, that regional ground water flow systems that are controlled by climate change are unexpectedly a major control over methanogenesis and carbon cycling in GLAP. Seismic profiles made showed that buried bedrock ridges particularly deflect regional groundwater flow upwards towards the land surface and towards raised bog landforms. In addition, high-resolution GPS measurements from data stations funded by this DOE project have shown this year that the peakland land surface elevation changes daily on a scale of cms, and seasonally on a scale of 10s of cm. This most recent observation is exciting because it may reflect episodic degassing of free phase methane from the peat column to the atmosphere, a source for methane previously unaccounted for by methane researchers.

Distribution of fish assemblages in Lajes Reservoir, Rio de Janeiro, Brazil

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F. G. ARAÚJO

Full Text Available Spatial distribution of fish assemblages in Lajes Reservoir, a 30 km² impoundment in Rio de Janeiro State (Lat. 22º42'-22º50'S; Long. 43º53'-44º05'W was assessed to detect patterns of available habitat use by the fish. A standardized monthly sampling program was carried out from January to December 1994 at three zones of the reservoir (upper, near tributary mouths; middle; and lower, near the dam. Fishes were caught by gillnets, (50 m long, 3 m height, with mesh ranging having from 25 to 45 mm between knots, submerged during 12 hours. A total of 5,089 fishes were collected comprising 15 species, 14 genera and 9 families. Loricariichthys spixii, Astyanax bimaculatus, Parauchenipterus striatulus, Astyanax fasciatus parahybae, Oligosarchus hepsetus, Rhamdia parahybae, Hypostomus affinis, and Geophagus brasiliensis were the most abundant species, each contributing above 1% of the total number. Loricariichthys spixii was the dominant species, contributing over 80% of total number and biomass. Fish abundance, number of species, and biomass were higher in the upper zone, but differences from this overall pattern were shown by some species. Loricariichthys spixii and Rhamdia parahybae were more abundant in the upper zone, while all other species showed no differences in their abundance among the zones. Seasonal environmental variables of temperature, pH, transparency, and water level did not show a clear association with fish occurrence. Most fish used the different zones of the reservoir with no clear sign of spatial separation. High dominance of L. spixii, reduced abundance of reolific species Leporinus copelandii and Cyphocharax gilberti, and presence of introduced species such as Cichla monoculus and Tilapia rendalli are indications of antropic effects in the fish community.

Some new species of Caryospora (Apicomplexa: Eimeriidae from brazilian snakes, and a re-description of C. jararacae Carini, 1939

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Ralph Lainson

1991-09-01

Full Text Available The mature ooxysts of six new species of Caryospora are described from the faeces of Brazilian snakes. They are differentiated from other species previously recorded from reptiles, largely on the size and shape of the oocyst and sporocyst, structure of the oocyst wall, and presence or absence of a polar body. C. paraensis n. sp., and C. carajasensis n. sp., are from the "false coral", Oxyrhopus petola digitalis; C. pseustesi n. sp., from the "egg-eater", Pseustes sulphureus sulphureus; C. epicratesi n. sp., from the "red boa", Epicrates cenchria cenchria; and C. micruri n. sp., and C. constancieae n. sp., from the "coral snake", Micrurus spixii spixii. A re-description is given of C. jararacae Carini, 1939, from the "jararaca" Bothrops atrox, embodying some additional morphological features.

Anatomia Funcional e Morfometria do Intestino no Teleostei (Pisces de Água Doce Surubim (Pseudoplatystoma coruscans - Agassiz, 1829

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Seixas Filho José Teixeira de

2001-01-01

Full Text Available Os objetivos do presente trabalho foram estudar a anatomia funcional e a morfometria comparativas nos intestinos médio e no reto, do peixe Teleostei, surubim, Pseudoplatystoma coruscans (Agassiz, 1829 (Siluriformes, Siluroidei, Pimelodidae, de hábito alimentar carnívoro, em duas classes de tamanho, visando fornecer referência à nutrição para o ajuste de diferentes sistemas de alimentação artificial para essa espécie nativa. Por meio destes estudos concluiu-se que o intestino do surubim, sob o ponto de vista morfológico, deve ser denominado, de intestino médio e reto, devido a presença da valva ileorretal e da invaginação valvar intestinal entre esses segmentos. Em relação ao padrão de enrolamento do intestino, apesar do plano geral do intestino médio e do reto ter sido mantido, as alças do intestino médio apresentaram arranjo indefinido, não tendo sido determinado um arranjo-padrão para a espécie. O arranjo intestinal é compatível ao da maioria de peixes carnívoros, ou predominantemente carnívoro, uma vez que seu intestino é quase retilíneo; contudo, as circunvoluções das alças finais do intestino médio talvez possam ser vistas como adaptações a um possível regime onívoro, preferencialmente carnívoro. As pregas intestinais encontram-se mais complexas e desenvolvidas no intestino dos exemplares da segunda classe de tamanho. Procurando estabelecer relações entre o arranjo das pregas das mucosas e a velocidade de transporte do alimento no intestino médio da espécie estudada, sugere-se que o padrão longitudinal, com numerosas anastomoses retardam o avanço do alimento em sentido aboral, o que possibilita maior período digestivo e, conseqüentemente, maior aproveitamento dos nutrientes, pela exposição do material alimentar à mucosa intestinal por período maior, além de contribuir para a preparação do bolo fecal. As pregas da mucosa próxima ao ânus têm direção longitudinal, sugerindo auxílio na

Ingestion and selection of suprabenthic crustaceans by small-sized fishes in a lower saltmarsh system

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Yoko Wakabara

1996-01-01

Full Text Available This study was performed in the lower saltmarsh system of the Arrozal, in the Cananéia lagoon estuarine region (25º02'S - 47º56'W, Brazil. Suprabenthic fauna was surveyed Wlth a small sledge and fishes were captured with casting and set nets to analyse: crustacean fauna as food for local fish species; difference in the diet at different times of the year; if there is diet overlap between species and the feeding behaviour of the species analysed. The fauna of Arrozal is poor in species, dominated mainly by Metamysidopsis alongata atlantica, Acartia lilljeborgi, Atylus minikoi, decapod larvae, and reveals a strong seasonal variation. The fishes were ali camivorous with suprabenthic crustacean as their main food resource. Seasonal changes in food supply are also reflected in the diet. Of the 12 flSh species collected six were opportunistlc feeders whereas six others were selective feeders. Food overlap value of 0.08 for ali of the fish community indicates an almost completely distinct food niches. The increased overlapping of summer food between Cathorops spixii and species of Group 11 and between Oligoplites sp and species of Group I seems to have two different explanations: 1 the mmIDishing of food supply for species feeding on benthic originated suprabenthic crustaceans and 2 overabundance of planktonic forms of suprabenthos as well as a period of high feeding activity of fishes with such diet.O presente estudo foi realizado no infralitoral contíguo à marisma, na Ponta do Arrozal, região estuarina lagunar de Cananéia (25º02'S - 47º56'W, Brasil. A fauna suprabêntica foi amostrada com uma pequena draga e os peixes capturados com tarrafa e rede de espera, com a finalidade de analisar: a composição de espécies dos crustáceos suprabênticos como itens alimentares dos peixes; diferenças na dieta em diferentes época do ano; se ocorre sobreposição alimentar entre as espécies e o comportamento alimentar: das espécies de peixes

Apuntes sobre la reproduccion de algunos Bagres marinos

NARCIS (Netherlands)

Luengo, José A.

1973-01-01

Mouthbreeding in the male, and modifications of the pelvic fins of the female are recorded for the first time in Selenaspis herzbergii. The pelvic girdle of Selenaspis herzbergii is compared with those of Sciadeichthys proops, Arius spixii, and Bagre marinus. Data are given on eggs and fry in the

Coralsnake Venomics: Analyses of Venom Gland Transcriptomes and Proteomes of Six Brazilian Taxa.

Science.gov (United States)

Aird, Steven D; da Silva, Nelson Jorge; Qiu, Lijun; Villar-Briones, Alejandro; Saddi, Vera Aparecida; Pires de Campos Telles, Mariana; Grau, Miguel L; Mikheyev, Alexander S

2017-06-08

Venom gland transcriptomes and proteomes of six Micrurus taxa ( M. corallinus , M. lemniscatus carvalhoi , M. lemniscatus lemniscatus , M. paraensis , M. spixii spixii , and M. surinamensis ) were investigated, providing the most comprehensive, quantitative data on Micrurus venom composition to date, and more than tripling the number of Micrurus venom protein sequences previously available. The six venomes differ dramatically. All are dominated by 2-6 toxin classes that account for 91-99% of the toxin transcripts. The M. s. spixii venome is compositionally the simplest. In it, three-finger toxins (3FTxs) and phospholipases A₂ (PLA₂s) comprise >99% of the toxin transcripts, which include only four additional toxin families at levels ≥0.1%. Micrurus l. lemniscatus venom is the most complex, with at least 17 toxin families. However, in each venome, multiple structural subclasses of 3FTXs and PLA₂s are present. These almost certainly differ in pharmacology as well. All venoms also contain phospholipase B and vascular endothelial growth factors. Minor components (0.1-2.0%) are found in all venoms except that of M. s. spixii . Other toxin families are present in all six venoms at trace levels (venom components differ in each venom. Numerous novel toxin chemistries include 3FTxs with previously unknown 8- and 10-cysteine arrangements, resulting in new 3D structures and target specificities. 9-cysteine toxins raise the possibility of covalent, homodimeric 3FTxs or heterodimeric toxins with unknown pharmacologies. Probable muscarinic sequences may be reptile-specific homologs that promote hypotension via vascular mAChRs. The first complete sequences are presented for 3FTxs putatively responsible for liberating glutamate from rat brain synaptosomes. Micrurus C-type lectin-like proteins may have 6-9 cysteine residues and may be monomers, or homo- or heterodimers of unknown pharmacology. Novel KSPIs, 3× longer than any seen previously, appear to have arisen in three

Comparative analysis of microsatellite variability in five macaw species (Psittaciformes, Psittacidae: application for conservation

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Flavia T. Presti

2011-01-01

Full Text Available Cross-amplification was tested and variability in microsatellite primers (designed for Neotropical parrots compared, in five macaw species, viz., three endangered blue macaws (Cyanopsitta spixii [extinct in the wild], Anodorhynchus leari [endangered] and Anodorhynchus hyacinthinus [vulnerable], and two unthreatened red macaws (Ara chloropterus and Ara macao. Among the primers tested, 84.6% successfully amplified products in C. spixii, 83.3% in A. leari, 76.4% in A. hyacinthinus, 78.6% in A. chloropterus and 71.4% in A. macao. The mean expected heterozygosity estimated for each species, and based on loci analyzed in all the five, ranged from 0.33 (A. hyacinthinus to 0.85 (A. macao. As expected, the results revealed lower levels of genetic variability in threatened macaw species than in unthreatened. The low combined probability of genetic identity and the moderate to high potential for paternity exclusion, indicate the utility of the microsatellite loci set selected for each macaw species in kinship and population studies, thus constituting an aid in planning in-situ and ex-situ conservation.

Coralsnake Venomics: Analyses of Venom Gland Transcriptomes and Proteomes of Six Brazilian Taxa

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Steven D. Aird

2017-06-01

Full Text Available Venom gland transcriptomes and proteomes of six Micrurus taxa (M. corallinus, M. lemniscatus carvalhoi, M. lemniscatus lemniscatus, M. paraensis, M. spixii spixii, and M. surinamensis were investigated, providing the most comprehensive, quantitative data on Micrurus venom composition to date, and more than tripling the number of Micrurus venom protein sequences previously available. The six venomes differ dramatically. All are dominated by 2–6 toxin classes that account for 91–99% of the toxin transcripts. The M. s. spixii venome is compositionally the simplest. In it, three-finger toxins (3FTxs and phospholipases A2 (PLA2s comprise >99% of the toxin transcripts, which include only four additional toxin families at levels ≥0.1%. Micrurus l. lemniscatus venom is the most complex, with at least 17 toxin families. However, in each venome, multiple structural subclasses of 3FTXs and PLA2s are present. These almost certainly differ in pharmacology as well. All venoms also contain phospholipase B and vascular endothelial growth factors. Minor components (0.1–2.0% are found in all venoms except that of M. s. spixii. Other toxin families are present in all six venoms at trace levels (<0.005%. Minor and trace venom components differ in each venom. Numerous novel toxin chemistries include 3FTxs with previously unknown 8- and 10-cysteine arrangements, resulting in new 3D structures and target specificities. 9-cysteine toxins raise the possibility of covalent, homodimeric 3FTxs or heterodimeric toxins with unknown pharmacologies. Probable muscarinic sequences may be reptile-specific homologs that promote hypotension via vascular mAChRs. The first complete sequences are presented for 3FTxs putatively responsible for liberating glutamate from rat brain synaptosomes. Micrurus C-type lectin-like proteins may have 6–9 cysteine residues and may be monomers, or homo- or heterodimers of unknown pharmacology. Novel KSPIs, 3× longer than any seen

Varanus exanthematicus (Bosc, 1792, Apalone spinifera emoryi (Le Sueur, 1827 y Gopherus berlandieri (Agassiz, 1857: reptiles exóticos en el área urbana de Puerto Vallarta, Jalisco, México

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Cupul-Magaña, Fabio Germán

2011-10-01

Full Text Available Varanus exanthematicus (Bosc, 1792; Material examinado: 1 ejemplar, hembra, longitud hocico-punta de la cola 628 mm, colectado el 8 de febrero del 2011 en una calle del área urbana de Puerto Vallarta, Jalisco, 20º 35' 48" N y 105º 13' 52" O, col. personal de la Subdirección de Ecología Municipal del H. Ayuntamiento de Puerto Vallarta, depositado y en resguardo del Reptilario Cipactli del Centro Universitario de la Costa de la Universidad de Guadalajara en Puerto Vallarta, Jalisco, México (permiso de funcionamiento del reptilario INE/ CITES/DGVS-CR-IN-0610-JAL./00; no hay número de registro individual del ejemplar. Gopherus berlandieri (Agassiz, 1857; Material examinado: 1 ejemplar, macho, longitud de caparazón 270 mm, colectado el 4 de mayo del 2005 en un parque urbano del Barrio Santa María de Puerto Vallarta, Jalisco, 20º 37' 53" N y 105º 12' 4" O, col. personal de la Policía Ecológica del H. Ayuntamiento de Puerto Vallarta, Jalisco, depositada y en resguardo en una casa particular en la ciudad de León, Guanajuato (esta ciudad se encuentra aproximadamente a 370 km al noreste de Puerto Vallarta; no hay más datos del registro. Apalone spinifera emoryi (Le Sueur, 1827; Material examinado: 1 ejemplar, macho, longitud del caparazón 240 mm, capturado el 20 de mayo del 2011 en una laguna artificial de agua dulce del área suburbana de Puerto Vallarta, Jalisco, 20º 42' 15" N y 105º 13' 18" O, col. Helios Hernández, depositado y en resguardo del Reptilario Cipactli del Centro Universitario de la Costa de la Universidad de Guadalajara en Puerto Vallarta, Jalisco, México (permiso de funcionamiento del reptilario INE/ CITES/DGVS-CR-IN-0610-JAL./00; no hay número de registro individual del ejemplar.

The Geologic History of Lake of the Woods, Minnesota, Reconstructed Using Seismic-Reflection Imaging and Sediment Core Analysis

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Hougardy, Devin D.

The history of glacial Lake Agassiz is complex and has intrigued researchers for over a century. Over the course of its ˜5,000 year existence, the size, shape, and location of Lake Agassiz changed dramatically depending on the location of the southern margin of the Laurentide Ice Sheet (LIS), the location and elevation of outflow channels, and differential isostatic rebound. Some of the best-preserved sequences of Lake Agassiz sediments are found in remnant lake basins where erosional processes are less pronounced than in adjacent higher-elevation regions. Lake of the Woods (LOTW), Minnesota, is among the largest of the Lake Agassiz remnant lakes and is an ideal location for Lake Agassiz sediment accumulation. High-resolution seismic-reflection (CHIRP) data collected from the southern basin of LOTW reveal up to 28 m of stratified lacustrine sediment deposited on top of glacial diamicton and bedrock. Five seismic units (SU A-E) were identified and described based on their reflection character, reflection configuration, and external geometries. Three prominent erosional unconformities (UNCF 1-3) underlie the upper three seismic units and indicate that deposition at LOTW was interrupted by a series of relatively large fluctuations in lake level. The lowermost unconformity (UNCF-1) truncates uniformly draped reflections within SU-B at the margins of the basin, where as much as four meters of sediment were eroded. The drop in lake level is interpreted to be contemporaneous with the onset of the low-stand Moorhead phase of Lake Agassiz identified from subaerial deposits in the Red River Valley, Rainy River basin, and Lake Winnipeg. A rise in lake level, indicated by onlapping reflections within SU-C onto UNCF-1, shifted the wave base outwards and as much as 11 m of sediment were deposited (SU-C) in the middle of the basin before a second drop, and subsequent rise, in lake level resulted in the formation of UNCF-2. Reflections in the lower part of SU-D onlap onto UNCF-2

Oceanographic temperature, salinity, oxygen, phosphate, total phosphorus, silicate, nitrite, pH, alkalinity measurements collected using bottle on multiple platforms in the Pacific, Atlantic, Arctic, Mediterranean from 1910 to 1982 (NODC Accession 0038350)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, nutrients, oxygen, and other measurements found in dataset OSD taken from the AGASSIZ; A., ALBACORE and other platforms in the Coastal N...

NOAA Photo Library - The Coral Kingdom

Science.gov (United States)

has only begun within the past 200 years. Charles Darwin, James Dwight Dana, and Louis Agassiz were photographs found here that will help you learn more about coral reefs in this album, visit the following

B chromosomes in the species Prochilodus argenteus (Characiformes, Prochilodontidae: morphologicalidentity and dispersion

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Manolo Penitente

2015-03-01

Full Text Available B chromosomes have attracted the attention of Neotropical fish cytogeneticists in recent years, both for their remarkable occurrence in this group and also because of the interest in studies of the genetic structure and role played in the genome of these organisms. The aim of this study was to report the first occurrence of supernumerary chromosomes in Prochilodus argenteus (Agassiz, 1829, this being the fifth carrier species among thirteen within the genus Prochilodus (Agassiz, 1829. The extra elements identified in this species are small sized heterochromatic chromosomes characterized by a low mitotic instability index, being very similar to other supernumerary chromosomes described in the species of the genus Prochilodus. Morphology, structure and dispersion of the supernumerary genomic elements which occur in species of this genus are discussed aiming to better understand aspects involved the origin of supernumerary chromosomes and the differentiation process and relationships among species of this family.

Domestic, peridomestic and wild hosts in the transmission of Trypanosoma cruzi in the Caatinga area colonised by Triatoma brasiliensis

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Claudia Mendonça Bezerra

2014-11-01

Full Text Available The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place. This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis. Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals. Cytochrome b was used as a food source for wild insects. The serum prevalence in dogs was 38% (20/53, while in pigs it was 6% (2/34. The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112 and Kerodon rupestris 10% (11/112. Of the 749 triatomines collected in the household research, 49.3% (369/749 were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369. In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus. In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae. The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous.

Polycyclic aromatic hydrocarbons in Saccoglossus kowalewskyi (Agassiz)

Science.gov (United States)

Carey, D. A.; Farrington, J. W.

1989-08-01

Hydrocarbon extracts were analyzed from Saccoglossus kowalewskyi, a deposit-feeding enteropneust worm, and from surface sediments from Cape Cod, MA. Worms were held in experimental aquaria in sieved sediments and flowing seawater for four months and then fed sediments mixed with creosote, lampblack or clean sediment for two weeks as analogues of sediments containing degraded oil and pyrogenic compounds. Worms from all treatments contained polyaromatic hydrocarbons (PAHs) in amounts and composition that indicate that the worms were contaminated with weathered No. 2 fuel oil before our experimental treatment and that the contamination persisted for four months in clean conditions. The contamination was not detected in the clean sediments used in the experiment. The worms accumulated steroid transformation products in greater abundance than the odd chain n-alkanes that dominated the sediment extractions. This may indicate selective assimilation of algal detritus and microbial products over salt marsh detritus. Worms, actively feeding during the experiment, contained 1-3 × 10 -6 g g -1 dry weight of unknown brominated compounds which were not detected in the sediments. These compounds are similar to bromopyrroles found elsewhere in enteropneusts, polychaetes and bacteria and may cause substantial interference in analyses for some industrial pollutants.

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Indian Academy of Sciences (India)

Unknown

After a doctorate in Paleontology (1967) at Columbia University, S J Gould went to Harvard where he spent the rest of his career, becoming the Alexander Agassiz Professor of Zoology in 1982. As a paleontologist, he was a specialist of gastropod molluscs from West Indies. But he soon became involved in broader and ...

Science at Harvard University: Historical Perspectives, edited by Clark A. Elliott and Margaret W. Rossiter. Lehigh University Press, Bethlehem, 1992

OpenAIRE

Christenson, Andrew L.

1992-01-01

This volume contains historical studies of several sciences as practiced at Harvard University. Two of these studies have relevance to the history of archaeology. A chapter by Toby Appel focuses upon the scientific career of Jeffries Wyman, first curator of Harvard's Peabody Museum. She contrasts Wyman's unassuming character with the dominating personality of his mentor and contemporary Louis Agassiz. Trained as a medi...

Enhanced ice sheet growth in Eurasia owing to adjacent ice-dammed lakes.

Science.gov (United States)

Krinner, G; Mangerud, J; Jakobsson, M; Crucifix, M; Ritz, C; Svendsen, J I

2004-01-29

Large proglacial lakes cool regional summer climate because of their large heat capacity, and have been shown to modify precipitation through mesoscale atmospheric feedbacks, as in the case of Lake Agassiz. Several large ice-dammed lakes, with a combined area twice that of the Caspian Sea, were formed in northern Eurasia about 90,000 years ago, during the last glacial period when an ice sheet centred over the Barents and Kara seas blocked the large northbound Russian rivers. Here we present high-resolution simulations with an atmospheric general circulation model that explicitly simulates the surface mass balance of the ice sheet. We show that the main influence of the Eurasian proglacial lakes was a significant reduction of ice sheet melting at the southern margin of the Barents-Kara ice sheet through strong regional summer cooling over large parts of Russia. In our simulations, the summer melt reduction clearly outweighs lake-induced decreases in moisture and hence snowfall, such as has been reported earlier for Lake Agassiz. We conclude that the summer cooling mechanism from proglacial lakes accelerated ice sheet growth and delayed ice sheet decay in Eurasia and probably also in North America.

Cubozoa e Scyphozoa (Cnidaria: Medusozoa de águas costeiras do Brasil Cubozoa and Scyphozoa (Cnidaria: Medusozoa from Brazilian coastal waters

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André C. Morandini

2005-09-01

Full Text Available As espécies de Cubozoa e Scyphozoa costeiras que ocorrem no Brasil são descritas, com base em espécimes de coleções de museus e exemplares recém-coletados. Chaves de identificação e um glossário também são apresentados. As espécies descritas são: Aurelia sp.; Cassiopea xamachana Bigelow, 1892; Chiropsalmus quadrumanus (Müller, 1859; Chrysaora lactea Eschscholtz, 1829; Drymonema dalmatinum Haeckel, 1880; Linuche unguiculata (Swartz, 1788; Lychnorhiza lucerna Haeckel, 1880; Nausithoe aurea Silveira & Morandini, 1997; Phyllorhiza punctata von Lendenfeld, 1884; Stomolophus meleagris Agassiz, 1862; Tamoya haplonema Müller, 1859 e Tripedalia cystophora Conant, 1897.Coastal species of Cubozoa and Scyphozoa occurring in Brazil are described, based on museum specimens and recently collected ones. Identification keys and a glossary are also presented. The listed species are: Aurelia sp.; Cassiopea xamachana Bigelow, 1892; Chiropsalmus quadrumanus (Müller, 1859; Chrysaora lactea Eschscholtz, 1829; Drymonema dalmatinum Haeckel, 1880; Linuche unguiculata (Swartz, 1788; Lychnorhiza lucerna Haeckel, 1880; Nausithoe aurea Silveira & Morandini, 1997; Phyllorhiza punctata von Lendenfeld, 1884; Stomolophus meleagris Agassiz, 1862; Tamoya haplonema Müller, 1859; and Tripedalia cystophora Conant, 1897.

Oligocene sharks from vicinity of Poljšica near Podnart, Slovenia

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Vasja Mikuž

2014-12-01

Full Text Available Poljšica and surroundings are known for numerous interesting fossil remains. Among the rarest fossil remains are vertebrates, and in the Poljšica Oligocene these consist exclusively of fish remains. In this contribution are considered six teeth of sharks, five belonging to species Carcharias cuspidatus (Agassiz, 1843, except a single problematic tooth that can be attributed most probably to genus Cosmopolitodus.

Noteworthy records of reptiles from natural open vegetation areas in plateau and coastal areas of the state of Santa Catarina, southern Brazil

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Ivo Rohling Ghizoni-Jr.

2009-09-01

Full Text Available The composition and geographic distribution of reptiles in Santa Catarina are little known, particularly in the open areas of its plateau (covered with ombrophylous steppe and Atlantic littoral (coastal dunes with thin, low, and predominant herbaceous vegetation known as restinga. Aiming to contribute to the knowledge of reptiles that inhabit these areas, this paper presents sixteen records of previously unknown or uncommon species in Santa Catarina: Acanthochelys spixii, Anops kingii, Cnemidophorus lacertoides, C. vacariensis, Leptotyphlops munoai, Mastigodryas b. bifossatus, Tantilla aff. melanocephala, Atractus reticulatus, Gomesophis brasiliensis, Lygophis flavifrenatus, Oxyrhopus r. rhombifer, Phalotris reticulatus, Philodryas agassizii, Xenodon dorbignyi, Micrurus altirostris and Bothrops pubescens. Aspects of the distribution and conservation of these species are discussed briefly.

East Weddell Sea echinoids from the JR275 expedition

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Thomas Saucède

2015-05-01

Full Text Available Information regarding the echinoids in this dataset is based on the Agassiz Trawl (AGT and epibenthic sledge (EBS samples collected during the British Antarctic Survey cruise JR275 on the RRS James Clark Ross in the austral summer 2012. A total of 56 (1 at the South Orkneys and 55 in the Eastern Weddell Sea Agassiz Trawl and 18 (2 at the South Orkneys and 16 in the Eastern Weddell Sea epibenthic sledge deployments were performed at depths ranging from ~280 to ~2060 m. This presents a unique collection for the Antarctic benthic biodiversity assessment of an important group of benthic invertebrates. In total 487 specimens belonging to six families, 15 genera, and 22 morphospecies were collected. The species richness per station varied between one and six. Total species richness represents 27% of the 82 echinoid species ever recorded in the Southern Ocean (David et al. 2005b, Pierrat et al. 2012, Saucède et al. 2014. The Cidaridae (sub-family Ctenocidarinae and Schizasteridae are the two most speciose families in the dataset. They comprise seven and nine species respectively. This is illustrative of the overall pattern of echinoid diversity in the Southern Ocean where 65% of Antarctic species belong to the families Schizasteridae and Cidaridae (Pierrat et al. 2012.

"Plants that Remind Me of Home": Collecting, Plant Geography, and a Forgotten Expedition in the Darwinian Revolution.

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Hung, Kuang-Chi

2017-02-01

In 1859, Harvard botanist Asa Gray (1810-1888) published an essay of what he called "the abstract of Japan botany." In it, he applied Charles Darwin's evolutionary theory to explain why strong similarities could be found between the flora of Japan and that of eastern North America, which provoked his famous debate with Louis Agassiz (1807-1873) and initiated Gray's efforts to secure a place for Darwinian biology in the American sciences. Notably, although the Gray-Agassiz debate has become one of the most thoroughly studied scientific debates, historians of science remain unable to answer one critical question: How was Gray able to acquire specimens from Japan? Making use of previously unknown archival materials, this article scrutinizes the institutional, instrumental, financial, and military settings that enabled Gray's collector, Charles Wright (1811-1885), to travel to Japan, as well as examine Wright's collecting practices in Japan. I argue that it is necessary to examine Gray's diagnosis of Japan's flora and the subsequent debate about it from the viewpoint of field sciences. The field-centered approach not only unveils an array of historical significances that have been overshadowed by the analytical framework of the Darwinian revolution and the reception of Darwinism, but also places a seemingly domestic incident in a transnational context.

Soft-bottom macrobenthic faunal associations in the southern Chilean glacial fjord complex

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Carlos Ríos

2005-12-01

Full Text Available Macrobenthic associations were investigated at 29 sampling stations with a semi-quantitative Agassiz trawl, ranging from the South Patagonian Icefield to the Straits of Magellan in the South Chilean fjord system. A total of 1,895 individuals belonging to 131 species were collected. 19 species belong to colonial organisms, mainly Bryozoa (17 species and Octocorallia (2 species. The phylum Echinodermata was the most diverse in species number (47 species, with asteroids (25 species and ophiuroids (13 species being the best represented within this taxon. Polychaeta was the second dominant group in terms of species richness (46 species. Multidimensional scaling ordination (MDS separated two station groups, one related to fjords and channels off the South Patagonian Icefield and the second one to stations surrounding the Straits of Magellan. 45 species account for 90% of the dissimilarity between these two groups. These differences can mainly be explained by the influence of local environmental conditions determined by processes closely related to the presence/absence of glaciers. Abiotic parameters such as water depth, type of sediment and chemical features of the superficial sediment were not correlated with the numbers of individuals caught by the Agassiz trawl in each group of sampling stations.

Epidemiologia da doença de Chagas no Ceará VIII - estudo da infecção de animais por T. cruzi no município de Morada Nova

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J. E. Alencar

1977-02-01

Full Text Available Foram examinados 1.368 mamíferos em ecótopos naturais ou artificiais: 443 cães com 2,5% positivos; 605 gatos com 0,7%, 65 roedores domésticos com 4,6%, 6 coelhos e 10 cobaias negativos. Dentre os animais silvestres, foram examinados 115 preás (Galea s. spixii com 2,3% positivos, 12 "cassacos" (Didelphis azarae dos quais 9 positivos; 5 quirópteros, 5 punáres (Cercomys c. laurentius e 3 pebas (Dasypus sexcinctus negativos. A amostra apresentada é suficiente para considerada a existência de ciclos doméstico e silvestre de T. cruzi na área estudada e considerada endêmica da Doença de Chagas.

Modeling Agassiz's Desert Tortoise Population Response to Anthropogenic Stressors

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Mojave Desert tortoise (Gopherus agassizii) populations are exposed to a variety of anthropogenic threats, which vary in nature, severity, and frequency. Tortoise management in conservation areas can be compromised when the relative importance of these threats is not well underst...

The porcellanid crabs of the Isla Gorgona, Pacific Coast of Colombia, with a description of Clastotoechus gorgonensis sp. nov. (Crustacea: Anomura)

OpenAIRE

Werding, B.; Haig, J.

1982-01-01

A collection of porcellanid crabs was made on che Isla Gorgona, Colombia, during a one week period, sampling as completely as possible a number of different biotopes. The majority of the 16 species in six genera that were collected occurred in the formations of pocilloporid corals and between stones in the sublittoral zone. Clastotoechus gorgonensis sp. nov. lives in the burrows of the sea urchin Echinometra vanbrunti A. Agassiz in the intertidal zone. Seven species are new additions to the ...

A Literature Review of Archaeological, Historical, and Paleontological Resources of the Sheyenne River Basin in North Dakota

Science.gov (United States)

1977-01-01

description of the Red River valley area was derived from Shay (1967: 231-237) and Scoby et. al. (1973). The Red River valley per se is flat except where...it is inter- rupted by the Sheyenne delta escarpment and the glacial Lake Agassiz shorelines ( Scoby et. al. 1973: 16). Surface drainage in the area is...very poor with runoff tending to collect in low lying areas ( Scoby et. al. 1973: 23). Prior to inten- sive drainage the area may have possessed many

Embryonic and larval development of Brycon amazonicus (SPIX & AGASSIZ, 1829

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A. C. S. Sampaio Nakauth

Full Text Available Abstract The objective of this study was to describe the embryonic and larval development of Brycon amazonicus, featuring the main events up to 50 hours after fertilization (AF. The material was provided by the Aquaculture Training, Technology and Production Center, Presidente Figueiredo (AM. The characterization was based on stereomicroscopic examination of the morphology of eggs, embryos and larvae and comparison with the literature. Matrinxã eggs are free, transparent, and spherical, with a perivitelline space of 0.56 ± 0.3 mm. The successive divisions give rise to cells with 64 blastomeres during the first hour AF. The gastrula stage, beginning 02 h 40 min AF, was characterized by progressive regression cells and the formation of the embryonic axis, leading to differentiation of the head and tail 05 h 30 min AF. From 06 to 09 h AF the somites, notochord, otic and optic vesicles and otoliths were observed, in addition to heart rate and the release of the tail. The larvae hatched at 10 h 30 min AF (29.9 °C, with a total length of 3.56 ± 0.46 mm. Between 19 and 30 h AF, we observed 1 pigmentation and gut formation, 2 branchial arches, 3 pectoral fins, 4 a mouth opening and 5 teeth. Cannibalism was initiated earlier (34 h AF which was associated with rapid yolk absorption (more than 90% until 50 h AF, signaling the need for an exogenous nutritional source. The environmental conditions (especially temperature influenced the time course of some events throughout the embryonic and larval development, suggesting the need for further studies on this subject.

Finding Ernst Mayr's Plato.

Science.gov (United States)

Powers, Jack

2013-12-01

Many biologists have accepted Ernst Mayr's claim that evolutionary biology undermined an essentialist or typological view of species that had its roots in Platonic philosophy. However, Mayr has been accused of failing to support with textual evidence his attributions to Plato of these sorts of views about biology. Contemporary work in history and philosophy of biology often seems to take onboard Mayr's account of Plato's view of species. This paper seeks to provide a critical account of putative inconsistencies between an evolutionary view of species and Platonic philosophy with renewed attention to the Platonic texts in light of recent Plato scholarship; I argue that claims that Plato held an essentialist view of species inconsistent with evolutionary biology are inadequately supported by textual evidence. If Mayr's essentialist thesis fails, one might think that the intuition that Platonic philosophy is in tension with Darwinian evolution could nonetheless be accounted for by Plato's apparent privileging of a certain sort of teleological explanation, a thesis that Mayr suggests in his 1959 paper on Louis Agassiz. However, this thesis also faces difficulties. Ernst Mayr's Plato is more likely to be found in the writings of anti-evolutionary 19th century biologists like Mayr's frequent target, Agassiz, than in a cautious reading of the Platonic dialogues themselves. Interlocutors in discussions of the history of biological thought and classificatory methods in biology should be cautious in ascribing views about biology to Plato and using terms like "Platonic essentialism." Copyright © 2013 Elsevier Ltd. All rights reserved.

Estructura de la comunidad de peces en el sistema Candelaria-Panlau, Campeche, México

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Luis Amado Ayala-Pérez

1998-09-01

Full Text Available Se describe el comportamiento de los parámetros de temperatura, salinidad, transparencia del agua y temperatura ambiente, y de la abundancia y diversidad de la comunidad del peces del sistema Candelaria-Panlau en escalas temporal y espacial. Los trabajos de campo se realizaron de manera mensual en cinco estaciones entre abril de 1993 y abril de 1994. La comunidad de peces quedó representada por 50 especies con 7 926 organismos y 144.7 kg de peso. Los valores de abundancia y diversidad de la comunidad fueron: 0.09 ind/m², 1.61 g/m² 18.25 g/ind, H’n = 1.879, J = 0.475 y D = 5.681. Las especies con dominio ecológico fueron: Cathorops melanopus, Diapterus rhombeus, Anchoa mitchilli, Sphoeroides testudineus, Bairdiella chrysura, B. ronchus, Cynoscion arenarius, y C. nebulosus, que en conjunto representan el 90.9 % en número y el 78.9 % en peso de la captura total. Las matrices de valores de los parámetros ambientales y de abundancia numérica de la comunidad de peces, fueron sometidas a un análisis de factores con el método de extracción de componentes principales, su representación gráfica confirma la definición de especies dominantes y demuestra que la salinidad, estación cinco y mes de febrero son los componentes que caracterizan al sistema y a la comunidad de peces.The environmental and ecological patterns of the fish community in Candelaria-Panlau system (Mexico are described. Parameters of the water temperature, salinity and transparency, and density, biomass and diversity of the fish community were analyzed. Between April 1993 and April 1994 five stations were sampled monthly. The fish community had 50 species (7 926 individuals, 144.7 kg of weight. The abundance and diversity values for the fish community were: 0.09 ind/m² ; 1.61 g/m²; 18.25 g/ind ; H'n = 1.879; J = 0.475 and D = 5.681. The species with ecological dominance were: Cathorops melanopus, Diapterus rhombeus, Anchoa mitchilli, Sphoeroides testudineus, Bairdiella

Development of the inverted visceral yolk sac in three species of caviids (Rodentia, Caviomorpha, Caviidae).

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Miglino, M A; Franciolli, A L R; de Oliveira, M F; Ambrósio, C E; Bonatelli, M; Machado, M R F; Mess, A

2008-08-01

Guinea pig related rodents possess numerous derived placental characters. We attempt to identify diversity within the visceral yolk sac and its association with the chorioallantoic placenta in three species of caviids, two of them possessing a capsule formed by the decidua that covers the chorioallantoic placenta. The results verify that in early pregnancy all three species have an inverted yolk sac placenta. In advanced pregnancy the species differ: Galea spixii, as representative without a capsule, bear a yolk sac in apposition to the chorioallantoic placenta with signs of exchange activity until term. Galea is similar to other caviomorphs in this respect. In Dasyprocta leporina and Cuniculus paca, the representatives possessing a capsule, the yolk sac endoderm lacks signs of substance exchange. Evidently, the presence of a capsule prevents such an interaction. The variations established here must be considered if animal models for human placentation are required which have restricted access to the chorioallantoic placenta from the outside.

Evaluación comparativa de dos métodos para determinar la actividad de fosfolipasa A en venenos de serpientes

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Fanny Lazo

2014-06-01

Full Text Available Se ha evaluado la actividad de fosfolipasa A en seis venenos de serpientes comparando las ventajas de un método espectrofotométrico, previamente adaptado a nuestras condiciones de laboratorio, frente al método macroscópico de retardo en la coagulación de una emulsión lipoproteica. En ambos casos, la actividad de fosfolipasa A estuvo presente en los venenos de Micrurus spixii, Crotalus durissus, Bothrops brazili, Lachesis muta y Bothrops atrox y la actividad decreció en orden. En cambio, la actividad de la enzima en el veneno de Micrurus surinamensis sólo fue detectada por el método espectrofotométrico. Así mismo, los resultados basados en la cantidad de veneno utilizado para medir la actividad, mostraron una mayor sensibilidad con el método espectrofotométrico en comparación con el método macroscópico ya que se requirieron cantidades menores en el orden de 2 a 10 veces.

Registros notáveis de répteis de áreas abertas naturais do planalto e litoral do Estado de Santa Catarina, sul do Brasil

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Ivo Rohling Ghizoni-Junior

2009-06-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2009v22n3p129 A composição e a distribuição dos répteis em Santa Catarina são pouco conhecidas, particularmente em suas áreas abertas naturais do planalto (estepe ombrófila e do litoral (faixa litorânea de restingas com dunas. Visando contribuir com o conhecimento dos répteis nestas áreas, são apresentados registros de dezesseis espécies anteriormente desconhecidas ou com poucos registros para Santa Catarina: Acanthochelys spixii, Anops kingii, Cnemidophorus lacertoides, C. vacariensis, Leptotyphlops munoai, Mastigodryas b. bifossatus, Tantilla aff. melanocephala, Atractus reticulatus, Gomesophis brasiliensis, Lygophis flavifrenatus, Oxyrhopus r. rhombifer, Phalotris reticulatus, Philodryas agassizii, Xenodon dorbignyi, Micrurus altirostris e Bothrops pubescens. São discutidos brevemente aspectos sobre a distribuição e a conservação destas espécies.

The role of the northward-directed (sub)surface limb of the Atlantic Meridional Overturning Circulation during the 8.2 ka Event

Science.gov (United States)

Tegzes, A. D.; Jansen, E.; Telford, R. J.

2014-02-01

The so-called "8.2 ka Event" has been widely regarded as a major climate perturbation over the Holocene. It is most readily identifiable in the oxygen-isotope records from Greenland ice cores as an approximately 160 yr-long cold interval between 8250-8090 yr BP. The prevailing view has been that the cooling over Greenland, and potentially over the northern North Atlantic at least, was triggered by the catastrophic final drainage of the Agassiz-Ojibway proglacial lake as part of the remnant Laurentide Ice Sheet collapsed over Hudson Bay at around 8420 ± 80 yr BP. The consequent freshening of surface waters in the northern North Atlantic Ocean and the Nordic Seas resulted in weaker overturning, hence reduced northward heat transport. Here we present proxy records from site JM97-MD95-2011 on the mid-Norwegian Margin indicating a (sharp) decline in the strength of the eastern branch of the Atlantic Inflow into the Nordic Seas immediately following a uniquely large drop in (sub)surface ocean temperatures coeval with the lake outbursts. We propose that the final drainage of Lake Agassiz-Ojibway was accompanied by a major iceberg discharge from Hudson Bay, which resulted in the cooling of the northward-directed northern Gulf Stream-North Atlantic Drift-Norwegian Atlantic Current system. Since our current-strength proxy records from the mid-Norwegian Margin do not evidence an exceptionally strong reduction in the main branch of the Atlantic Inflow into the Nordic Seas at the time, we argue that a chilled northward-directed (sub)surface-current system and an already colder background climate state could be the main factors responsible for the 8.2 ka climate perturbation.

The scientist as historian: Paulo Vanzolini and the origins of zoology in Brazil.

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Bastos, Francisco Inácio; Sá, Magali Romero

2011-12-01

The Brazilian Paulo Vanzolini is one of the leading herpetologists worldwide. Besides his publications as a zoologist and his activities as a former museum curator and policymaker, Vanzolini pursued a long-life career as a musician and contributed to many different fields such as biostatistics, biogeography and the history of science. The paper analyzes his historical contributions to a key chapter of science in Southern America, the legacy of the so-called traveler naturalists. His analyses comprise major scientists such as Marcgrave, Spix, von Martius, Wied-Neuwied, Castelnau, and Agassiz, are informed by re-analyses of original sources and represent an invaluable repository of historical and scientific information.

Science A history

CERN Document Server

Gribbin, John

2002-01-01

From award-winning science writer John Gribbin, "Science: A History" is the enthralling story of the men and women who changed the way we see the world, and the turbulent times they lived in. From Galileo, tried by the Inquisition for his ideas, to Newton, who wrote his rivals out of the history books; from Marie Curie, forced to work apart from male students for fear she might excite them, to Louis Agassiz, who marched his colleagues up a mountain to prove that the ice ages had occurred. Filled with pioneers, visionaries, eccentrics and madmen, this is the history of science as it has never been told before.

La contaminación por metales pesados en la Ciénaga Grande de Santa Marta, Caribe colombiano La contaminación por metales pesados en la Ciénaga Grande de Santa Marta, Caribe colombiano

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Campos C. Néstor Hernando

1990-09-01

Full Text Available Se dan los resultados de los estudios sobre la contaminación por metales pesados en la Ciénaga Grande de Santa Marta. Las determinaciones se realizaron en el material en suspensión, en los bivalvos Crassostrea rhizophorae e Isognomon alatus y en los peces Gathorops spixii y Ariopsis bonillai. Los análisis de los metales Cd, Zn y Cu en el material en suspensión permitieron determinar que las mayores descargas de estos metales se suceden principalmente desde el Río Magdalena a través del Canal del Clarín y de los ríos que fluyen del piedemonte de la Sierra Nevada de Santa Marta. La comparación de los contenidos en bivalvas permiten determinar la importancia de estos organismos como bioindicadores. Los análisis en las dos especies de peces mostraron una diferenciación en la capacidad de acumulación entre una y otra.  Al comparar los contenidos de metales entre los diferentes tipos de muestras con los cambios en los contenidos en el material en suspensión y la salinidad, se observó que estos dos parámetros son principalmente los que controlan la biodisponibilidad de los metales y además afectan los procesos fisiológicos de los organismos, aumentando o disminuyendo la capacidad de bioacumulación. Results of the studies of heavy metals pollution in the Ciénaga Grande de Santa Marta are provided. The determinations have been done on the suspended matter, on the bivalves Crassostrea rhizophorae and Isognomon alatus, and in the fishes Gathorops spixii and Ariopsis bonillai. The analysis of Cd, Zn and Cu in the suspended matter led to determine that the discharges come principally from the Río Magdalena through the Canal del Clarín and the rivers coming from the Sierra Nevada de Santa Marta. Comparisons of the concentration in bivalves show the importance of this organisms as bioindicators. The analysis in both fish species show a difference in their capacity of accumulation. Comparison of the metals contents between different types

Gait transition and oxygen consumption in swimming striped surfperch Embiotoca lateralis Agassiz

DEFF Research Database (Denmark)

Cannas, M.; Schaefer, J.; Domenici, P.

2006-01-01

A flow-through respirometer and swim tunnel was used to estimate the gait transition speed (Up-c) of striped surfperch Embiotoca lateralis, a labriform swimmer, and to investigate metabolic costs associated with gait transition. The Up-c was defined as the lowest speed at which fish decrease...... the use of pectoral fins significantly. While the tail was first recruited for manoeuvring at relatively low swimming speeds, the use of the tail at these low speeds [as low as 0·75 body (fork) lengths s-1, LF s-1) was rare (..., either in addition to pectoral fins or during burst-and-coast mode. Oxygen consumption increased exponentially with swimming speeds up to gait transition, and then levelled off. Similarly, cost of transport (CT) decreased with increasing speed, and then levelled off near Up-c. When speeds =Up...

Induced reproduction and early development histology of Oscar Astronotus ocellatus (Agassiz, 1831).

Science.gov (United States)

Paes, Maria do Carmo Faria; Makino, Lilian Cristina; Vasquez, Leonardo Avendaño; Fernandes, João Batista Kochenborger; Valentin, Fernanda Nogueira; Nakaghi, Laura Satiko Okada

2015-04-01

Oscar (Astronotus ocellatus) is an important fish from the Amazon Basin that has great potential for fish farming, human consumption, sport fishing and fish keeping. This study aimed to evaluate the effect of two hormonal treatments on the induction of artificial reproduction in broodstock and to describe the histological development of embryos and larvae. Broodstocks were selected and induced using two different hormones: (i) extract of carp pituitary (ECP); and (ii) synthetic human chorionic gonadotropin (hCG). Spawnings were transferred to hatcheries, collected at pre-established times, processed and analysed by histology. Astronotus ocellatus did not respond well to induced reproduction. From 16 couples of breeding fish, only five out of the eight females released oocytes after the hormonal action time, three with hCG and two with ECP; just one male responded positively to hCG. Oscar eggs were oval, and semi-adhesive, the yolk contained granules, and egg diameter was approximately 1.65 ± 0.057 to 1.98 ± 0.038 mm. Development from the initial collection (IC) point until the total absorption of the yolk lasted 315 h, at an average temperature of 27.45 ± 2.13°C. Several events marked embryonic and larval development, including the formation of the optic cup, forebrain, otic vesicle and cephalic divisions. The newly hatched larvae had non-pigmented eyes, and a closed mouth and anus, as well as the presence of adhesive glands on the head. Larval development was characterized by formation of the heart, liver, gaseous bladder, gills, pronephros, brain, fins and also the digestive tract. These results provide important information for the rearing and reproduction of A. ocellatus.

Landscape evolution in south-central Minnesota and the role of geomorphic history on modern erosional processes

Science.gov (United States)

Gran, K.B.; Belmont, P.; Day, S.S.; Finnegan, N.; Jennings, C.; Lauer, J.W.; Wilcock, P.R.

2011-01-01

The Minnesota River Valley was carved during catastrophic drainage of glacial Lake Agassiz at the end of the late Pleistocene. The ensuing base-level drop on tributaries created knickpoints that excavated deep valleys as they migrated upstream. A sediment budget compiled in one of these tributaries, the Le Sueur River, shows that these deep valleys are now the primary source of sediment to the Minnesota River. To compare modern sediment loads with pre-European settlement erosion rates, we analyzed incision history using fluvial terrace ages to constrain a valley incision model. Results indicate that even thoughthe dominant sediment sources are derived from natural sources (bluffs, ravines, and streambanks), erosion rates have increased substantially, due in part to pervasive changes in watershed hydrology.

Larval fish in the surf zone of Pontal do Sul beach, Pontal do Paraná, Paraná, Brazil

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Rodrigo Santiago Godefroid

1999-01-01

Full Text Available A total of 6,575 larvae in the preflexion, flexion and post-flexion stages of 15 families, 26 genera and 29 species were captured in the surf zone of Pontal do Sul beach, Paraná, Brazil. Samples of the families Gerreidae and Scianidae predominated and larvae of Eucinostomus argenteus (Baird&Girard, 1854, Micropogonias furnieri (Desmarest, 1823, Eucinostomus gula (Cuvier, 1830, Menticirrhus ameri-canus (Linnaeus, 1758 and Anchoa tricolor (Agassiz, 1829 were the most dominant species. Greater abundance of larvae was observed during the summer, followed by winter and in a less extent during spring and autumn. The number of species was greater in the summer, and there were no significant differences in the rest of the seasons.

Two new species of Creptotrema (Digenea: Allocreadiidae from South America Dos especies nuevas de Creptotrema (Digenea: Allocreadiidae de América del Sur

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Stephen S. Curran

2008-08-01

Full Text Available Two new digenean species belonging in Creptotrema Travassos, Artigas and Pereira, 1928 are described from specimens stored in the invertebrate collection at the Museum of Natural History, Geneva, Switzerland. Creptotrema lamothei n. sp. is described from Ageneiosus brevifilis Valenciennes in Cuvier and Valenciennes, 1840 (Siluriformes: Ageneiosidae, Auchenipterus nuchalis (Spix and Agassiz, 1829 (Siluriformes: Auchenipteridae, and Bryconops melanurus (Bloch, 1794 (Characiformes: Characidae in the Paraguay River, Paraguay. Creptotrema sucumbiosa n. sp. is described from Tetragonopterus argenteus Cuvier, 1816 (Characiformes: Characidae in Río Aquarico, Ecuador. Creptotrema lamothei differs from its congeners by having testes with irregular rather than entire outlines. Creptotrema sucumbiosa differs from its congeners by having a bilobed rather than entire ovary. Both C. lamothei and C. sucumbiosa differ from their other congeners by having relatively longer posttesticular spaces in their bodies, representing 25-30% and 24-28% of body length respectively, compared with approximately 6-19% in other species.Dos especies nuevas de digéneos pertenecientes a Creptotrema Travassos, Artigas y Pereira, 1928 fueron descritas de ejemplares depositados en la colección de invertebrados del Museo de Historia Natural de Ginebra, Suiza. Creptotrema lamothei n. sp. fue descrita en Ageneiosus brevifilis Valenciennes in Cuvier y Valenciennes, 1840 (Siluriformes: Ageneiosidae, Auchenipterus nuchalis (Spix y Agassiz, 1829 (Siluriformes: Auchenipteridae, y Bryconops melanurus (Bloch, 1794 (Characiformes: Characidae en el río Paraguay, Paraguay. Creptotrema sucumbiosa n. sp. fue descrita de Tetragonopterus argenteus, Cuvier 1816 (Characiformes: Characidae en el río Aquarico, Ecuador. Creptotrema lamothei difiere de sus congéneres por tener testículos con contornos irregulares en contraste con los que presentan contornos enteros. Creptotrema sucumbiosa difiere de

Holocene evolution of lakes in the forest-tundra biome of northern Manitoba, Canada

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Hobbs, William O.; Edlund, Mark B.; Umbanhowar, Charles E.; Camill, Philip; Lynch, Jason A.; Geiss, Christoph; Stefanova, Vania

2017-03-01

The late-Quaternary paleoenvironmental history of the western Hudson Bay region of Subarctic Canada is poorly constrained. Here, we present a regional overview of the post-glacial history of eight lakes which span the forest-tundra biome in northern Manitoba. We show that during the penultimate drainage phase of Lake Agassiz the lake water had an estimated pH of ∼6.0, with abundant quillwort (Isöetes spp.) along the lakeshore and littoral zone and some floating green algae (Botryococcus spp. and Pediastrum sp.). Based on multiple sediment proxies, modern lake ontogeny in the region commenced at ∼7500 cal yrs BP. Pioneering diatom communities were shaped by the turbid, higher alkalinity lake waters which were influenced by base cation weathering of the surrounding till following Lake Agassiz drainage. By ∼7000 cal yrs BP, soil development and Picea spp. establish and the lakes began a slow trajectory of acidification over the remaining Holocene epoch. The natural acidification of the lakes in this region is slow, on the order of several millennia for one pH unit. Each of the study lakes exhibit relatively stable aquatic communities during the Holocene Thermal Maximum, suggesting this period is a poor analogue for modern climatic changes. During the Neoglacial, the beginning of the post-Little Ice Age period represents the most significant climatic event to impact the lakes of N. Manitoba. In the context of regional lake histories, the rate of diatom floristic change in the last 200-300 years is unprecedented, with the exception of post-glacial lake ontogeny in some of the lakes. For nearly the entire history of the lakes in this region, there is a strong linkage between landscape development and the aquatic ecosystems; however this relationship appears to become decoupled or less strong in the post-LIA period. Significant 20th century changes in the aquatic ecosystem cannot be explained wholly by changes in the terrestrial ecosystem, suggesting that future

Anthropometric specimens and picturesque curiosities: the photographic orchestration of the “black” body (Brazil, circa 1865

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Rodríguez BE

2012-05-01

Full Text Available In Against Race Paul Gilroy writes that the “race producing” activity unleashed in the eighteenth and nineteenth-centuries “required a synthesis of logos with icon, of formal scientific rationality with something else, something visual and aesthetic” (1. During this period, scientific discourses that elaborate the concept of race adopt new technologies, especially photography. In this article, I am particularly interested in analyzing how the “black” body is arranged photographically. I probe some examples taken from the archives collected by the Swiss scientist Louis Agassiz and the photographer Christiano Júnior in mid-19th century Rio de Janeiro. Objective: to question how these visual artifacts contributed to the re-assemblage of racial discourses precisely at the moment when the black body was invested with legal subjectivity

Fish farming of native species in Colombia: current situation and perspectives

DEFF Research Database (Denmark)

Cruz-Casallas, P. E.; Medina-Robles, V. M.; Velasco-Santamaria, Y. M.

2011-01-01

. The Colombian pisciculture is based on red Tilapia Oreochromis sp. (Linnaeus), Rainbow trout Oncorhynchus mykiss (Walbaum) and cachama blanca Piaractus brachypomus (Cuvier), which currently represent around 96% of the total national production. The remaining 4% comes from other farmed species such as bocachico......In Colombia and the rest of the world, the decrease in capture fisheries production has turned the aquaculture into an alternative source of protein for the populations food security as well as an important productive activity, generating employment and income for the rural communities...... Prochilodus magdalenae (Steindachner), carp Cyprinus carpio (Linnaeus) and yamu Brycon amazonicus (Spix & Agassiz). From the three main fish species, cachama blanca is the only native species, which has shown excellent performance in pond farming due to its rusticity, omnivorous habits, docility, meat quality...

Dinâmica populacional da matrinxã Brycon amazonicus (Characidae na Amazônia Central Population dynamics of matrinxã Brycon amazonicus (Characidae in Central Amazon

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Leocy C. dos Santos Filho

2009-06-01

Full Text Available The matrinxã, Brycon amazonicus (Spix & Agassiz, 1829 is one of the most important fishery resources of the Amazonas state. Its population dynamics in Central Amazon was analyzed based on total landing and biometry data registered in the main landing port of Manaus, between 1994 and 2002. Growth and mortality rates were estimated separately for the rivers Purus, Madeira and Solimões. Differences in size structure and growth curves suggest that different population units exist among these rivers, requiring individualized evaluation and fisheries management strategies. The analysis of the yield per recruit does not indicate overexploitation. However, the highest relative exploitation rate was observed in the Madeira river. The suggested management strategies are related to restrictions to the fishery in the main fishing grounds during the migratory dispersal period, instead of restrictions during reproductive periods.

The Status of Romanogobio uranoscopus (Agassiz, 1828 Species, in Maramureş Mountains Nature Park (Romania

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Curtean-Bănăduc Angela

2017-03-01

Full Text Available The condition of aquatic habitats typically occupied by Romanogobio uranoscopus within the Maramureş Mountains Natural Park fluctuates, in the best cases, between reduced to average. Good or excellent conservation status is now absent for populations of this species in the researched area. The identified human impact types (poaching, minor riverbeds morphodynamic changes, solid and liquid natural flow changes, destruction of the riparian vegetation and bush vegetation, habitat fragmentation/isolation of population, organic and mining pollution and displaced fish that are washed away during the periodic flooding in the lotic sectors uniformized by humans are contributing to the diminished ecological state of Romanogobio uranoscopus habitats and for that reason populations. Romanogobio uranoscopus is now considered a rare species in the studied basin but where this species was specified as missing, it has been registered with a restorative potential.

A role for land surface forcing of North Atlantic climate and isotope signals during the 8.2kyr event?

Science.gov (United States)

Hopcroft, Peter; Valdes, Paul

2014-05-01

An important example of abrupt climate change occurred 8200 years ago in the North Atlantic and is generally known as the 8.2kyr event. This abrupt ~160 year cooling appears to coincide with the final drainage of the ice-dammed Lakes Agassiz and Ojibway. The resultant influx of meltwater to the North Atlantic is assumed to have perturbed the Atlantic Meridional Overturning circulation, reducing northward heat transport and causing widespread cooling. Numerous lines of evidence support this theory, with reconstructions showing changes in deep water formation, reductions in salinity and evidence of sea-level rise. Coupled general circulation model (GCM) simulations driven with realistic estimates of the meltwater flux show a regional cooling but fail to replicate the duration or the magnitude of this event in comparison with proxy archives. Meltwater injection was not the only rapid climate forcing in operation at this time. Drainage of the pro-glacial lakes would have had a profound effect on the boundary layer heat fluxes over North America, with potential teleconnections further afield. In this work we use an isotope-enabled version of the coupled GCM HadCM3 with boundary conditions appropriate for the time period of 9kyr (including ice sheets, greenhouse gases and orbital parameters). This model tracks oxygen isotopes throughout the hydrological cycle allowing more robust comparison with proxy archives. We analyse the impact of the removal of a lake area corresponding to Lakes Agassiz and Ojibway at this time and present sensitivity tests designed to analyse the contributions from lake removal, orographic change and the assumed isotopic content of the pro-glacial lakes. The results show a distinct pattern of cooling across North America (in the annual mean) with an apparent teleconnection to the Barents Sea, where there is warming associated with sea-ice reduction. The isotopic implications depend on the initial isotopic content of the pro-glacial lake. Assuming

Size structure and sex composition of Eurypodius latreillii Guérin, 1828 (Brachyura and Pagurus comptus White, 1847 (Anomura in southern Chile

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R. Soto

1999-12-01

Full Text Available The decapod crustaceans Eurypodius latreillii (Brachyura and Pagurus comptus (Paguridae were the most frequently occurring species in Agassiz trawl (AGT samples obtained during the Chilean - German - Italian Victor Hensen Expedition in the Straits of Magellan and south of the Beagle Channel. Sex composition and length structure aspects were studied using the material from 15 stations in the two areas, which comprised 773 specimens of E. latreillii and 647 P. comptus. The size frequency of both species was characterized by the presence of small individuals in shallow waters. The sex composition varied with depth, indicating a dominance of E. latreillii females in deep waters, whereas no such pattern was observed in P. comptus. These differences may be caused by epizoites of E. latreillii and the availability of vacant gastropod shells for P. comptus, in addition to geographical aspects and life-cycle patterns of these species

Quaternary dating methods

International Nuclear Information System (INIS)

Mahaney, W.C.

1984-01-01

The papers in this book cover absolute, relative and multiple dating methods, and have been written by specialists from a number of different earth sciences disciplines - their common interest being the dating of geological materials within the Quaternary. Papers on absolute dating methods discuss radiocarbon, uranium-series, potassium argon, 40 Ar/ 39 Ar, paleomagnetic, obsidian hydration, thermoluminescence, amino acid racemization, tree rings, and lichenometric techniques. Those on relative dating include discussions on various geomorphic relative age indicators such as drainage density changes, hypsometric integrals, bifurcation ratios, stream junction angles, spur morphology, hillslope geometry, and till sheet characteristics. The papers on multiple dating cite examples from the Rocky Mountains, Australia, Lake Agassiz Basin, and the Southern Andes. Also included is the panel discussion which reviews and assesses the information presented, and a field trip guide which discusses the sequences of Wisconian tills and interlayered lacustrine and fluvial sediments. (orig.)

First cytogenetic analysis of Ichthyoelephas humeralis (Günther, 1860 by conventional and molecular methods with comments on the karyotypic evolution in Prochilodontidae

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Mauro Nirchio Tursellino

2016-11-01

Full Text Available We used conventional cytogenetic techniques (Giemsa, C-banding, Ag-NOR, and fluorescent in situ hybridization (FISH with 5S and 18S rDNA probes to investigate the karyotype and cytogenetic characteristics of Ichthyoelephas humeralis (Günther, 1860 from Ecuador. The specimens studied have a karyotype with 2n=54 biarmed chromosomes (32 M + 22 SM and C-positive heterochromatin located on the centromeric, pericentromeric, interstitial, and terminal regions of some chromosomes. The nucleolus organizer regions occurred terminally on the long arm of chromosome pair 2. FISH confirmed the presence of only one 18S rDNA cluster with nonsyntenic localization with the 5S rDNA. Cytogenetic data allow us to refute the earlier morphological hypothesis of a sister relationship between Semaprochilodus Fowler, 1941 and Ichthyoelephas Posada Arango, 1909 and support the molecular proposal that Ichthyoelephas is a sister group to the monophyletic clade containing Prochilodus Agassiz, 1829 and Semaprochilodus.

Introduction to the study of natural history edited and annotated by Christoph Irmscher

CERN Document Server

2017-01-01

This book features Louis Agassiz’s seminal lecture course in which the Swiss-American scientist, a self-styled “American Humboldt,” summarized the state of zoological knowledge in his time. Though Darwin’s theory of evolution would soon dismantle his idealist science, Agassiz’s lectures are nonetheless modern in their insistence on the social and cultural importance of the scientific enterprise. An extensive, well-illustrated introduction by Agassiz’s biographer, Christoph Irmscher, situates Agassiz’s lectures in the context of his life and nineteenth-century science, while also confronting the deeply problematic aspects of his legacy. Profusely annotated, this edition offers fascinating insights into the history of science and appeals to anyone with an interest in zoology and natural history. “Christoph Irmscher provides a scholarly and insightful analysis of the intentions and beliefs of Louis Agassiz, a larger-than-life scientist of the mid-19th century and fierce opponent of Charles Darwi...

Revised estimates of Greenland ice sheet thinning histories based on ice-core records

DEFF Research Database (Denmark)

Lecavalier, B.S.; Milne, G.A.; Fisher, D.A.

2013-01-01

-based reconstructions and, to some extent, the estimated elevation histories. A key component of the ice core analysis involved removing the influence of vertical surface motion on the dO signal measured from the Agassiz and Renland ice caps. We re-visit the original analysis with the intent to determine if the use...... of more accurate land uplift curves can account for some of the above noted discrepancy. To improve on the original analysis, we apply a geophysical model of glacial isostatic adjustment calibrated to sea-level records from the Queen Elizabeth Islands and Greenland to calculate the influence of land...... in this selection is further complicated by the possible influence of Innuitian ice during the early Holocene (12-8 ka BP). Our results indicate that a more accurate treatment of the uplift correction leads to elevation histories that are, in general, shifted down relative to the original curves at GRIP, NGRIP, DYE...

A Common Eurasian Fish Tapeworm, Caryophyllaeides fennica (Cestoda), in Western North America: Further Evidence of 'Amphi-Pacific' Vicariance in Freshwater Fish Parasites.

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Oros, Mikuláš; Choudhury, Anindo; Scholz, Tomáš

2017-10-01

The freshwater fish faunas of the Palaearctic and Nearctic regions show similarities but also notable differences, resulting in diverse distributions of their parasites. Relatively few parasite species occur in both regions and fewer still have been examined using molecular data. We report a rare example of 'amphi-Pacific' distribution, involving the common Palaearctic parasite, the caryophyllidean cestode Caryophyllaeides fennica (Schneider, 1902), in the chiselmouth Acrocheilus alutaceus Agassiz and Pickering, 1855, an endemic cyprinid in northwestern Nearctic, Oregon. Available information on nonnative fish species in Oregon suggests that the parasite is native to the area and not introduced. Molecular data (18S ribosomal [r]DNA, 28S rDNA, internal transcribed spacer 2, and cytochrome c oxidase subunit 1 gene) indicate very little genetic divergence between representatives from the Palaearctic and Nearctic, and possibly a relatively more recent colonization of the Nearctic region by this cestode via the Beringian land bridge. This is remarkable considering that Acrocheilus has reportedly been in Oregon since the Miocene.

On the paraphyly of Cytaeididae and placement of Cytaeis within the suborder Filifera (Hydrozoa: Anthoathecata)

KAUST Repository

Prudkovsky, A. A.

2016-06-17

Identification of hydrozoans of the family Cytaeididae L. Agassiz, 1862 is confused due to their morphological similarity, to the shortage of morphological characteristics, and to a lack of molecular data. In this study, sequences of nuclear and mitochondrial DNA markers were analyzed from hydroids of Cytaeis Eschscholtz, 1829 collected in the southern Red Sea on shells of Nassarius Duméril, 1805 (Gastropoda: Nassariidae), along with sequences of Cytaeis and Perarella Stechow, 1922 from GenBank. Analyses revealed the paraphyly of the family Cytaeididae, and indicate that the genus Cytaeis may actually belong to the family Bougainvilliidae Lütken, 1850 (Hydrozoa: Anthoathecata). Perarella species grouped within different families and far from Cytaeis species within phylogenetic trees. Additional studies are necessary to confirm the phylogenetic position and formally revise the taxonomy of Perarella. These results demonstrate the need to utilize molecular sequences in re-assessing the taxonomy and phylogeny of filiferan hydrozoans. © 2016 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg

On the paraphyly of Cytaeididae and placement of Cytaeis within the suborder Filifera (Hydrozoa: Anthoathecata)

KAUST Repository

Prudkovsky, A. A.; Nikitin, M. A.; Berumen, Michael L.; Ivanenko, Viatcheslav N.; Reimer, J. D.

2016-01-01

Identification of hydrozoans of the family Cytaeididae L. Agassiz, 1862 is confused due to their morphological similarity, to the shortage of morphological characteristics, and to a lack of molecular data. In this study, sequences of nuclear and mitochondrial DNA markers were analyzed from hydroids of Cytaeis Eschscholtz, 1829 collected in the southern Red Sea on shells of Nassarius Duméril, 1805 (Gastropoda: Nassariidae), along with sequences of Cytaeis and Perarella Stechow, 1922 from GenBank. Analyses revealed the paraphyly of the family Cytaeididae, and indicate that the genus Cytaeis may actually belong to the family Bougainvilliidae Lütken, 1850 (Hydrozoa: Anthoathecata). Perarella species grouped within different families and far from Cytaeis species within phylogenetic trees. Additional studies are necessary to confirm the phylogenetic position and formally revise the taxonomy of Perarella. These results demonstrate the need to utilize molecular sequences in re-assessing the taxonomy and phylogeny of filiferan hydrozoans. © 2016 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg

O litoral do Nordeste do Brasil como objeto científico darwinista: as prospecções de John Casper Branner, 1899-1911

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Almir Leal de Oliveira

2014-09-01

Full Text Available John Casper Branner, geólogo norte-americano, desenvolveu uma longa história de investigação no Brasil. Analisa-se, aqui, como ele tratou a geologia do litoral do Nordeste na Branner-Agassiz Expedition (1899 e na Stanford Expedition (1911. As expedições indicam como a geomorfologia das bacias sedimentares, dos recifes de arenito e dos recifes de corais foi caracterizada sob uma perspectiva evolutiva darwinista. Branner integrou o modelo de pesquisa de campo da história natural com as práticas da biologia moderna e da geologia dinâmica, e interpretou a evolução da formação geológica a partir dos fatores físico-químicos. Os estudos zoológicos identificaram o lugar da variação e das adaptações evolutivas das espécies marinhas isoladas como fator auxiliar da seleção natural.

Reconhecimento de frações do veneno de cobras corais brasileiras pelo soro antielapídico = Recognition of venom fractions from Brazilian coral snakes by antielapid serum

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Vidal, Bruno Prado Cortizo

2015-01-01

Full Text Available Objetivos: Investigar a capacidade do soro antielapídico produzido no Brasil na identificação de frações do veneno de seis espécies, incluindo as que constituem o pool de inoculação: Micrurus brasiliensis, M. corallinus, M. frontalis, M. lemniscatus, M. spixii e M. surinamensis. Métodos: As amostras utilizadas fazem parte do banco de venenos do Centro de Estudos e Pesquisas Biológicas, da Pontifícia Universidade Católica de Goiás. O soro antielapídico foi cedido pela Fundação Ezequiel Dias. As metodologias empregadas foram eletroforese e imunoblotting. Resultados: Foi demonstrada uma variabilidade toxinológica e uma capacidade também variável de reconhecimento desses componentes pelo soro antielapídico. A partir da técnica de western-blotting o soro antielapídico da Fundação Ezequiel Dias foi capaz de reconhecer a maioria, mas não todos os componentes presentes nos venenos analisados. Conclusões: Os resultados sugerem uma eficácia restrita do soro antielapídico já que o mesmo possui limitações quanto as espécies Amazônicas, o que reforça a necessidade de uma revisão dos estudos intra e interespecíficos dos venenos micrúricos

Influence of geologic layering on heat transport and storage in an aquifer thermal energy storage system

Science.gov (United States)

Bridger, D. W.; Allen, D. M.

2014-01-01

A modeling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in an aquifer thermal energy storage (ATES) system in Agassiz, British Columbia, Canada. Two 3D heat transport models were developed and calibrated using the flow and heat transport code FEFLOW including: a "non-layered" model domain with homogeneous hydraulic and thermal properties; and, a "layered" model domain with variable hydraulic and thermal properties assigned to discrete geological units to represent aquifer heterogeneity. The base model (non-layered) shows limited sensitivity for the ranges of all thermal and hydraulic properties expected at the site; the model is most sensitive to vertical anisotropy and hydraulic gradient. Simulated and observed temperatures within the wells reflect a combination of screen placement and layering, with inconsistencies largely explained by the lateral continuity of high permeability layers represented in the model. Simulation of heat injection, storage and recovery show preferential transport along high permeability layers, resulting in longitudinal plume distortion, and overall higher short-term storage efficiencies.

Some observations on the problem of jelly fish ingress in a power station cooling system at Kalpakkam, east coast of India

International Nuclear Information System (INIS)

Rajagopal, S.; Azariah, Jayapaul; Nair, K.V.K.

1989-01-01

The paper reports results of a study on the seasonal distribution and abundance of jelly fishes in the coastal waters of Kalpakkam in the context of their ingress into the cooling system of a power plant. Three species of jelly fishes Dactylometra quinquicirrha (L. agassiz), Crambionella stuhlmanni (Chun) and Chiropsalmus buitendijki (Horst) were found in such abundance as to cause blockage of the cooling water intake screens. The seasonal variation in the incidence of the jelly fishes clearly showed that the periods of maxima and minima were different for each species. During the period of study (February 1988 to April 1989) three maxima were noted - May, July and October. On any given single day, maximum quantity of jelly fishes collected from the travelling screens was 29 tonnes (21 July 1988). The data are discussed with respect of (i)qualitative and quantitative variations in the ingress of jelly fishes at Kalpakkam, (ii)operational problems associated with jelly fish ingress and (iii)possible approaches to combat the problem. (author). 1 tab., 4 figs., 9 ref s

Community of protozoans and metazoans parasitizing Auchenipterus nuchalis (Auchenipteridae, a catfish from the Brazilian Amazon

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Marcos Tavares Dias

2017-05-01

Full Text Available This paper describes the first study on parasite diversity in Auchenipterus nuchalis Spix & Agassiz, 1829 (Auchenipteridae. In 31 fish caught in a tributary of the Amazon River, 10,708 parasites were collected, such as Ichthyophthirius multifiliis, Piscinoodinium pilullare, Cosmetocleithrum striatuli, metacercariae of Posthodiplostomum sp, and larvae and adults of Procamallanus (Spirocamallanus inopinatus. These parasite species showed aggregated dispersion, except for C. striatuli, which had a uniform dispersion. The component community of parasites showed a low Brillouin diversity (0.67 ± 0.27, low species richness (3.5 ± 0.8 and low evenness (0.43 ± 0.17, and it was characterized by the presence of species with high prevalence and abundance. Protozoan species were the prevalent parasites, which may be a consequence of the host’s mode of life, while the low presence of endoparasites in A. nuchalis suggests that this fish may occupy an intermediate trophic level in the food web. These data represent the first record of such parasite species for this host.

First estimates of the probability of survival in a small-bodied, high-elevation frog (Boreal Chorus Frog, Pseudacris maculata), or how historical data can be useful

Science.gov (United States)

Muths, Erin L.; Scherer, R. D.; Amburgey, S. M.; Matthews, T.; Spencer, A. W.; Corn, P.S.

2016-01-01

In an era of shrinking budgets yet increasing demands for conservation, the value of existing (i.e., historical) data are elevated. Lengthy time series on common, or previously common, species are particularly valuable and may be available only through the use of historical information. We provide first estimates of the probability of survival and longevity (0.67–0.79 and 5–7 years, respectively) for a subalpine population of a small-bodied, ostensibly common amphibian, the Boreal Chorus Frog (Pseudacris maculata (Agassiz, 1850)), using historical data and contemporary, hypothesis-driven information–theoretic analyses. We also test a priori hypotheses about the effects of color morph (as suggested by early reports) and of drought (as suggested by recent climate predictions) on survival. Using robust mark–recapture models, we find some support for early hypotheses regarding the effect of color on survival, but we find no effect of drought. The congruence between early findings and our analyses highlights the usefulness of historical information in providing raw data for contemporary analyses and context for conservation and management decisions.

Aspectos biométricos y reproductivos de Boquichico Prochilodus nigricans Agassiz, 1829 (Pisces: Prochilodontidae en Ucayali, Perú

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José C. Riofrío Q.

2013-06-01

Full Text Available El conocimiento de la biología y pesquería de una especie explotada es esencial para un manejo racional y una producción sostenida. De febrero a diciembre de 1994 se colectó información de una de las especies más importantes por los volúmenes de desembarque en Ucayali, el boquichico (Prochilodus nigricans. Se analizaron aspectos biométricos (relación longitud total - peso total: LTPT y reproductivos (proporción por sexos, época de reproducción, tallas de madurez de esta especie. La relación LT-PT no mostró diferencias significativas entre las regresiones de machos y hembras (análisis de variancias residual F0,05 proponiéndose el empleo de una ecuación conjunta para la especie de la forma PT = 0,0211 LT 2,8592. La proporción sexual total no mostró diferencias significativas (χ 2 0,05 al asumir una relación 1:1. El análisis de la progresión de los estadios de madurez confirma la reproducción durante la temporada de elevación del nivel del río Ucayali (octubre-enero. La talla de madurez calculada para los machos fue de 24,5 cm y para las hembras de 26.1 cm, recomendándose esta última para el manejo de la pesquería.

Notes on the Bull shark Carcharhinus leucas in the lagoon region of Cananéia, Brazil

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V Sadowsky

1971-12-01

Full Text Available Ninety one young specimens and 3 adult females of BulI shark ("cação cabeça chata" caught in the lagoon region of Cananéia were examined, their tooth formula being 27/25 and the number of pre-caudal vertebrae ranging from 109 to 115. The proportion between the 1st and 2nd dorsal fins were found to be 2.3 and 2.8 for the young,and 2.9 to 3.1 for the adults. These data confirm that the studied form belongs to C. leuoas. Young occur regularly but in limited numbers.As regards the adults, however, females only appear during the short parturition period, i.e., from November to February. The number of embryos in the litters were from 7 to 9, their sizes ranging between 768-812 mm. The length of the smallest free young found was 697 mm, but young presumably 9 to 12 months old had 98 to 112 cm; between 21 and 24 months they were reaching 124 to 128 cm, that is, the same size they have when they start migrating to the open sea. The feeding inhibition phenomenon during the period of parturition was not observed in the female specimens caught in the lagoon. The more abundant species found in the stomach contents were: Arius spixii; Chloroscombrus chrysurus; A. grandicassus; A. barbus; Felichtys marinus; Genidens genidens; Chanophorus tajacica and Carcharhinus porosus.Noventa e um espécimes jovens e 3 fêmeas adultas de "cação cabeça chata" capturados na região lagunar de Cananeia foram examinados, constatando-se a fórmula dental 27/25 e número de vértebras pré-caudais entre 109 e 115.Verificouse que as proporções entre a la. nadadeira dorsal e a 2a. foram de 2.3 e 2.8 para os jovens e de 2.9 até 3.1 para os adultos.Ficou assim confirmado que a forma es tudada pertence a C. leuaas. É comum a ocorrência de jovens dentro da região estudada~ no entanto,quanto aos adultos,as fêmeas só são encontradas durante o período de parição, i.é, de novembro a fevereiro. Constatou-se que o número de embriões nas ninhadas foi de 7 a 9 e seus

Variabilidad espacial y temporal de la abundancia y diversidad de la comunidad de peces en la costa de Campeche, México Spatial and temporal variability of fish community abundance and diversity off the coast of Campeche, Mexico

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Luis Amado Ayala-Pérez

2012-03-01

Full Text Available La comunidad de peces en el sur del golfo de México es abundante y diversa y sus componentes se encuentran afectados por la captura incidental de la pesquería del camarón siete barbas. El presente trabajo describe y analiza los patrones de variación espacial y temporal de la abundancia y diversidad de la comunidad de peces, identificando las especies con dominio ecológico. Los muestreos se realizaron mensualmente entre febrero 2006 y enero 2007 en 37 sitios localizados desde la desembocadura del sistema Grijalva-Usumacinta hasta la desembocadura del sistema Chumpam-Balchacah al interior de la Laguna de Términos, en el estado de Campeche al sur del golfo de México. Se realizaron 444 arrastres experimentales con una red de prueba camaronera y se capturaron 26.386 peces con un peso conjunto de 407,1 kg. Se identificaron 94 especies agrupadas en 65 géneros y 38 familias. La abundancia y diversidad de la comunidad de peces se analizó en escalas espacial y temporal en términos de densidad (ind m-2, biomasa (g m-2, peso promedio (g ind-1, índice de diversidad (H'n, riqueza de especies (DMg e índice de equidad (J'. En cuanto a abundancia se distinguieron los altos valores registrados en agosto y septiembre, en sitios cercanos a las desembocaduras de los sistemas Grijalva-Usumacinta y Palizada-Del Este. La especie más importante en términos de abundancia fue el bagre Cathorops melanopus. Los intervalos de variación de los índices de diversidad en escala espacial fueron: H'n = 0,5-2,8 bits; Dmg = 2,6-5,3 sp. ind-1 y J'= 0,1-0,8 bits. En escala temporal los intervalos fueron H'n = 1,8-2,6 bits; Dmg = 5,1-6,7 sp. ind-1 y J'= 0,4-0,6 bits. Se identificaron nueve especies dominantes con 16.840 individuos y un peso conjunto de 278,5 kg, equivalente al 63,8% de la captura total.The fish community of the southern Gulf of Mexico is abundant and diverse, and its components are affected by the bycatch of the seabob shrimp fishery. The spatial and

A new psammosteid (Agnatha, Heterostraci from the Amata Regional Stage of the Main Devonian Field and morpho-histological types of discrete micromeric elements in the family Psammosteidae

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Vadim N. Glinskiy

2017-05-01

Full Text Available In memory of an outstanding palaeoichthyologist Elga Mark-Kurik The range of diversity of psammosteids from the family Psammosteidae is still poorly known. Here a new species, Psammosteus ramosus sp. nov. Glinskiy, from the Amata Regional Stage of the Main Devonian Field is described. Its morphology, ornamentation, histology of exoskeletal plates, and micromeric elements are compared with those of other representatives of the family Psammosteidae. The comparison shows a close relationship of the new species with Psammosteus falcatus Obruchev, P. kiaeri Halstead Tarlo and P. pectinatus Obruchev, a group of species that is significantly different from other representatives of the genus Psammosteus and constitutes a separate evolutionary lineage. On the basis of morphological and histological features we here differentiate in the fields of tesserae of Psammosteidae the discrete micromeric elements of the ‘basic type’, known in Psammosteus bergi (Obruchev, P. levis Obruchev, P. livonicus Obruchev, P. maeandrinus Agassiz, P. megalopteryx (Trautschold, P. praecursor Obruchev and Karelosteus weberi Obruchev, and micromeric elements of the ‘progressive type’, known in Psammosteus falcatus, P. cf. kiaeri and P. ramosus sp. nov. Glinskiy.

Climate-driven flushing of pore water in peatlands

Science.gov (United States)

Siegel, D. I.; Reeve, A. S.; Glaser, P. H.; Romanowicz, E. A.

1995-04-01

NORTHERN peatlands can act as either important sources or sinks for atmospheric carbon1,2. It is therefore important to understand how carbon cycling in these regions will respond to a changing climate. Existing carbon balance models for peatlands assume that fluid flow and advective mass transport are negligible at depth3,4, and that the effects of climate change should be essentially limited to the near-surface. Here we report the response of groundwater flow and porewater chemistry in the Glacial Lake Agassiz peat-lands of northern Minnesota to the regional drought cycle. Comparison of field observations and numerical simulations indicates that climate fluctuations of short duration may temporarily reverse the vertical direction of fluid flow through the peat, although this has little effect on water chemistry5. On the other hand, periods of drought persisting for at least 3-5 years produce striking changes in the chemistry of the pore water. These longer-term changes in hydrology influence the flux of nutrients and dissolved organic matter through the deeper peat, and therefore affect directly the rates of fermentation and methanogenesis, and the export of dissolved carbon compounds from the peatland.

Mudança na dieta da traíra Hoplias malabaricus (Bloch (Erythrinidae, Characiformes em lagoas da bacia do rio Doce devido à introdução de peixes piscívoros Diet changes of the trahira Hoplias malabaricus (Bloch (Erythrinidae, Characiformes due to piscivorous introductions in Rio Doce valley lakes

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Paulo dos Santos Pompeu

2001-12-01

Full Text Available Two piscivorous fishes, peacock bass (Cichla monoculus Spix & Agassiz, 1831 (Perciformes and piranha (Pygocentrus nattereri Kner, 1860 (Characiformes, were introduced in some Rio Doce valley lakes (19º50'S, 42º40'W for sport fisheries enhancement. As a consequence, small individuals and species were practically vanished in the host lakes. In this study, the effects of peacock bass and piranha introductions on the diet of a native piscivorous fish, the trahira - Hoplias malabaricus (Bloch, 1794 are presented. Trahira's diet from three lakes were was compared with the stomach contentsdiet of trahira's living in another between three lakes with and three withoutstocked with the piscivorous species peacock bass and piranha. In the lakes with introduced fishes species, the consumption of fish was significantly smaller and this food item have been this item partly replaced by aquatic invertebrates. This shift on of trahira's diet to the low abundance of its original prey, is attributed to the small fishes. This diet plasticity adaptative capacity he diet plasticity detected for trahira might be allowing its maintenance in the lakes with peacock bass and piranha.

Faunal diversity of the benthic amphipods (Crustacea of the Magellan region as compared to the Antarctic (preliminary results

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Claude de Broyer

1999-12-01

Full Text Available To investigate the marine benthic ecosystems of the Magellan region and to compare them with the better known Antarctic systems, three campaigns were recently carried out in this area: the Joint Magellan Victor Hensen Campaign 1994, the Polarstern ANT XIII/4 cruise 1996, and the Vidal Gormaz CIMAR FIORDO II cruise 1996. Numerous and diverse zoobenthos samples were collected mostly with an Agassiz trawl and with a small dredge, an epibenthic sledge, with baited traps or by diving. All gears together gathered more than 132,000 specimens of gammaridean and caprellidean amphipods. 137 species of gammaridean amphipods have been identified from the material to date. About 20% of these species appear to be new for science. This taxonomic work takes place in the framework of a general revision of the Southern Ocean amphipod fauna undertaken by theAntarctic Amphipodologists Network. A complete list of the benthic species of gammaridean and caprellidean amphipods is presented, including the zoogeographical distribution and the new records. The new abundant material collected, still under study, will allow a comparison of faunal diversity, zoogeographical and ecological traits of the Magellan benthic amphipod taxocoenoses with those of the West and East Antarctic benthos.

Associations between pycnogonids and hydroids from the Buenos Aires littoral zone, with observations on the semi-parasitic life cycle of Tanystylum orbiculare(Ammotheiidae

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Gabriel N. Genzano

2002-03-01

Full Text Available Abundance and seasonality of Tanystylum orbiculare Wilson, 1878 populations (Pycnogonida; Ammotheidae associated with Sarsia sarsii (Loven, 1836 and Tubularia crocea (Agassiz, 1862 (Hydrozoa; Anthomedusae are analysed and the semi-parasitic life cycle of this species is described. In the analysed population, the first larval stages were found exclusively as parasites of S. sarsii. During the attachment to the hydranths, protonymphon larvae of T. orbiculare feed by sucking the hydranths of the cnidarian. Change of host is not obligatory; juveniles and adults were found both on S. sarsii as on T. crocea, and adults were also observed on other invertebrates. In the Mar del Plata intertidal, Tanystylum orbiculare was the most common pycnogonid species on colonies of T. crocea and S. sarsii. Anoplodactylus petiolatus was less abundant on both species and A. assimilis was found only on T. crocea. Endeis spinosa is absent on hydroids from the Mar del Plata intertidal zone but ectoparasitic larvae and adults were found on Obelia longissima colonies from Mar del Plata harbour together with adults of T. orbiculare and A. petiolatus. Endoparasitic larvae of A. petiolatus were found associated with colonies of Bougainvillidae.

Influence of food restriction on the reproduction and larval performance of matrinxã, Brycon amazonicus (Spix and Agassiz, 1829

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ACS. Camargo

Full Text Available This work evaluated the effect of food restriction and refeeding of matrinxã females, Brycon amazonicus, on their reproductive performance and on the growth and survival of the progeny. Broodstocks were distributed in 8 earthen tanks (15 fish/tank and fish from 4 tanks were fed daily (G1 while fish from the other 4 tanks were fed for 3 days and not fed for 2 days (G2 during 6 months prior to artificial spawning. Among the induced females, 57% in G1 group and 45% in G2 group spawned and the mean egg weights were 208.1 g (G1 and 131.6 g (G2. Oocytes of G2 fish were smaller (1.017 ± 0.003 mm than oocytes of G1 fish (1.048 ± 0.002 mm. Fertilization (71.91 ± 12.6% and 61.18 ± 13.7% and hatching (61.28 ± 33.9% and 67.50 ± 23.4% rates did not differ between G1 and G2 fish. Larvae were collected at hatching and at 24, 48 and 72 hours of incubation and fixed for growth measurement. After incubation, fry were transferred to aquaria and sampled 1, 5, 9 and 15 days later. G1 and G2 larvae had similar weight (1.51 ± 0.15 and 1.46 ± 0.07 mg but the G2 length was significantly higher (6.26 ± 0.13 and 6.74 ± 0.14 mm. By the ninth day of rearing, G2 fry had higher weight (13.6 ± 0.26 and 18.9 ± 0.07 mg and length (11.8 ± 0.09 and 14.5 ± 0.04 mm but by the fifteenth day, G1 fry had higher weight (90.2 ± 1.19 and 68.6 ± 0.77 mg and length (18.8 ± 0.16 and 18.5 ± 0.04 mm than G2 fry. By the ninth day of rearing, when fry are recommended to be transferred to outdoor tanks, G2 fry were larger and after 15 days, fry produced by restricted-fed females showed higher survival. The survival rate of G2 progeny by the fifteenth day was significantly higher (24.7 ± 2.07% than that of G1 progeny (19.2 ± 1.91%. The ration restriction (35% reduction imposed on matrinxã broodstock during 6 months prior to spawning reduced the number of spawned females and the egg amount, but it did not affect fertilization and hatching rates. Otherwise restricted-female larvae were larger and presented higher survival.

Influence of food restriction on the reproduction and larval performance of matrinxã, Brycon amazonicus (Spix and Agassiz, 1829).

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Camargo, A C S; Urbinati, E C

2008-11-01

This work evaluated the effect of food restriction and refeeding of matrinxã females, Brycon amazonicus, on their reproductive performance and on the growth and survival of the progeny. Broodstocks were distributed in 8 earthen tanks (15 fish/tank) and fish from 4 tanks were fed daily (G1) while fish from the other 4 tanks were fed for 3 days and not fed for 2 days (G2) during 6 months prior to artificial spawning. Among the induced females, 57% in G1 group and 45% in G2 group spawned and the mean egg weights were 208.1 g (G1) and 131.6 g (G2). Oocytes of G2 fish were smaller (1.017 +/- 0.003 mm) than oocytes of G1 fish (1.048 +/- 0.002 mm). Fertilization (71.91 +/- 12.6% and 61.18 +/- 13.7%) and hatching (61.28 +/- 33.9% and 67.50 +/- 23.4%) rates did not differ between G1 and G2 fish. Larvae were collected at hatching and at 24, 48 and 72 hours of incubation and fixed for growth measurement. After incubation, fry were transferred to aquaria and sampled 1, 5, 9 and 15 days later. G1 and G2 larvae had similar weight (1.51 +/- 0.15 and 1.46 +/- 0.07 mg) but the G2 length was significantly higher (6.26 +/- 0.13 and 6.74 +/- 0.14 mm). By the ninth day of rearing, G2 fry had higher weight (13.6 +/- 0.26 and 18.9 +/- 0.07 mg) and length (11.8 +/- 0.09 and 14.5 +/- 0.04 mm) but by the fifteenth day, G1 fry had higher weight (90.2 +/- 1.19 and 68.6 +/- 0.77 mg) and length (18.8 +/- 0.16 and 18.5 +/- 0.04 mm) than G2 fry. By the ninth day of rearing, when fry are recommended to be transferred to outdoor tanks, G2 fry were larger and after 15 days, fry produced by restricted-fed females showed higher survival. The survival rate of G2 progeny by the fifteenth day was significantly higher (24.7 +/- 2.07%) than that of G1 progeny (19.2 +/- 1.91%). The ration restriction (35% reduction) imposed on matrinxã broodstock during 6 months prior to spawning reduced the number of spawned females and the egg amount, but it did not affect fertilization and hatching rates. Otherwise restricted-female larvae were larger and presented higher survival.

Sobrevivência e crescimento de larvas de surubim Pseudoplatystoma corruscans (Spix & Agassiz, 1829) sob diferentes condições alimentares

OpenAIRE

Sérgio Antônio Medeiros Marinho

2007-01-01

A produção comercial do surubim Pseudoplatystoma corruscans vem crescendo cada vez mais no país, onde vários são os aspectos relacionados ao cultivo dessa espécie, que requer cuidados extremos, principalmente nas fases iniciais, das quais, embora seja grande o número de indivíduos produzidos numa única desova, os organismos são extremamente frágeis. A substituição de várias espécies de plânctons nas dietas das larvas, por outras menos dispendiosas, ou seja, dietas artificiais vem sendo alvo d...

Reexamination of the holotype of Pseuderythrinus rosapinnis Hoedeman, 1950, a synonym of Hoplerythrinus unitaeniatus Agassiz, 1829 (Pisces, Characiformes, Erythrinidae)

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Jongh, de Bas O.

1991-01-01

The holotype and only known specimen of Pseuderythrinus rosapinnis Hoedeman, 1950 from Surinam is reexamined for the dentition of its palatal arch. Its morphometric and meristic data are compared with four species of erythrinids from the Guianas. Pseuderythrinus rosapinnis turns out to be a synonym

Seláquios do Acervo do Museu de Ciências da Terra / DNPM-RJ

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Alex Alves Souto

2005-01-01

Full Text Available Os seláquios depositados na Coleção de Peixes Fósseis do MCTer correspondem a uma amostragem da ocorrência do grupo no Brasil. São 86 registros, sendo 9 deles holótipos, no acervo, 32,5% dos exemplares são representantes do Devoniano e Permiano, 46,5% do Cretáceo e 21% do Cenozóico, que correspondem a 19 gêneros e 36 espécies. Devido a configuração cartilaginosa do seu esqueleto, o registro fóssil restringe-se a partes mineralizadas como dentes, escamas, espinhos de nadadeiras e cefálicos. Eventualmente, ocorre a preservação de um esqueleto completo incluindo partes moles como o Tribodus limae Brito & Ferreira, 1989. Do Paleozóico, destacam-se os espinhos de Xenacanthiformes e pertencem ao acervo os holótipos de Xenacanthus tocantinsensis Santos & Salgado, 1970; Xenacanthus albuquerquei (Santos, 1946 e Xenacanthus santaritensis Ragonha, 1986. Da ordem Ctenacanthiformes há os holótipos de Ctenacanthus gondwanus Santos, 1947 e Ctenacanthus maranhensis Santos, 1946; há um representante ainda, dos Eugeneodontiformes, síntipos de Anisopleurodontis pricei Santos 1994. Entre os seláquios cretáceos estão os Lamniformes, com os exemplares de Cretolamna serrata, (Agassiz, 1843 e Scapanorhynchus rapax (Quaas, 1902. Os Hibodontiformes constituem o grupo mais representativo do mesozóico, são espinhos de nadadeiras, espinhos cefálicos e alguns dentes de Hybodus sp. O holótipo de Hybodus florencei (Moraes Rego, 1960 da Formação Corumbataí, bem como o parátipo de Tribodus limae Brito & Ferreira 1989; da Formação Santana, bacia do Araripe, fazem parte do acervo do MCTer. Dos seláquios cenozóicos estão os representantes da Formação Pirabas, Mioceno do Estado do Pará, dos quais constam dois holótipos, Carcharhinus ackermanii, Santos & Travassos 1960 e Galeocerdo paulinoi Santos & Travassos, 1960; e um dente de Carcharocles megalodon (Agassiz,1835, o maior tubarão carnívoro já existente e alguns peixes fósseis que

Biologia reprodutiva e reprodução induzida de duas espécies de Characidae (Osteichthyes, Characiformes da bacia do São Francisco, Minas Gerais, Brasil Reproductive biology and induced breeding of two Characidae species (Osteichthyes, Characiformes from the São Francisco River basin, Minas Gerais, Brazil

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Yoshimi Sato

2006-03-01

Full Text Available Astyanax bimaculatus (Linnaeus, 1758 e Tetragonopterus chalceus Spix & Agassiz, 1829 são duas importantes espécies de peixes forrageiros da bacia do São Francisco. Espécimes destas duas espécies foram submetidos à indução da desova através de hipofisação, para observação de aspectos reprodutivos e obtenção de subsídios para definição de protocolo de reprodução artificial. Machos e fêmeas receberam dose única de extrato bruto de hipófise de carpa comum (6 mg/kg de peixe. A extrusão de ovócitos foi realizada cerca de 12,8 e 11 h após a aplicação da injeção de hipófise, respectivamente para A. bimaculatus e T. chalceus, com a temperatura da água a 26ºC. Mais de 70% das fêmeas das duas espécies responderam positivamente ao tratamento e as taxas médias de fertilização dos ovos foram acima de 70%. Os ovócitos de A. bimaculatus e T. chalceus são esféricos, opacos, demersais, levemente adesivos, de coloração amarela ou parda, e contendo em média respectivamente 4774 e 2563 ovos por grama de ova. O desenvolvimento embrionário nas duas espécies foi rápido, com duração de menos de um dia, estando a temperatura da água entre 24 e 25ºC.Astyanax bimaculatus (Linnaeus, 1758 and Tetragonopterus chalceus Spix & Agassiz, 1829 are two important foraging species occurring at the São Francisco River basin. Specimens from both species were submitted to spawning induction through hypophysation, to study some reproductive features and to obtain subsidiary information for the definition of the artificial reproduction protocol. Males and females were treated with a single dose of crude carp pituitary extract (6 mg/kg. In water at 26ºC, the extrusion of the oocytes was made 12,8 and 11 hours after the hypophisis injection, for A. bimaculatus and T. chalceus respectively. More than 70% of the females of both species showed a positive response to the treatment and mean egg fertilization rates were above 70%. The eggs of A

Food availability drives plastic self-repair response in a basal metazoan-case study on the ctenophore Mnemiopsis leidyi A. Agassiz

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Bading, Katharina Tissy; Kaehlert, Sarah; Chi, Xupeng

2017-01-01

-animals instead. Yet, the driving factors of this phenomenon have not been addressed so far. This study sheds new light on how differences in food availability affect self-repair choice and regeneration success in cydippid larvae of M. leidyi. As expected, high food availability favored whole-body regeneration....... However, under low food conditions half-animals became the preferential self-repair mode. Remarkably, both regenerating and half-animals showed very similar survival chances under respective food quantities. As a consequence of impaired food uptake after injury, degeneration of the digestive system would...... often occur indicating limited energy storage capacities. Taken together, this indicates that half-animals may represent an alternative energy-saving trajectory which implies self-repair plasticity as an adaptive trade-off between high regeneration costs and low energy storage capacities. We conclude...

The use of semen evaluation and assisted reproduction in Spix's macaws in terms of species conservation.

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Fischer, Dominik; Neumann, Daniel; Purchase, Cromwell; Bouts, Tim; Meinecke-Tillmann, Sabine; Wehrend, Axel; Lierz, Michael

2014-01-01

The Spix's macaw (Cyanopsitta spixii) is the rarest parrot on earth. The remaining captive population consists of 79 individuals. Captive propagation is ongoing to increase the number of individuals for future reintroduction back into the wild. Unfortunately, from 2004 to 2012, only 33 chicks hatched from 331 eggs. Semen evaluation and assisted reproduction might help to overcome this problem. Therefore, a recently developed electro-stimulated semen collection technique was used in Spix's macaws. Semen collection was successful in 39 of 78 attempts in 10 out of 17 males. Examination of the semen included evaluation of volume, color, consistency, contaminations and pH, as well as determination of motility, viability, morphology, concentration, and total count of spermatozoa. The median volume of semen samples was 5.6 µl. On average, 34.7 ± 21.9% (median 30%) of the sperm were motile and 23.1 ± 22.1% (median 16.5%) were progressively motile. In addition to spermatozoa, round cells were detected in the samples. Median sperm concentration was 15,500/µl (range 500-97,500/µl) and median viability was 50% (range 5-87%). Morphological examination revealed in 26.5% normal spermatozoa, high numbers of malformations of the head (50.2%) and tail region (20.5%), with 29% of all sperm showing multiple abnormalities. Artificial insemination was performed in three females; two eggs laid after artificial insemination had spermatozoa present on the perivitelline layer, suggesting the possible success of the insemination technique. Although no fertilization could be demonstrated, these preliminary results are promising, as they indicate that assisted reproduction might be a tool for species conservation in the Spix's macaw. © 2014 Wiley Periodicals Inc.

Identification of Reactive and Refractory Components of Dissolved Organic Nitrogen by FT-ICR Mass Spectrometry

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Cooper, W. T.; Podgorski, D. C.; Osborne, D. M.; Corbett, J.; Chanton, J.

2010-12-01

Dissolved organic nitrogen is an often overlooked but potentially significant bioavailable component of dissolved organic matter. Studies of bulk DON turnover have been reported, but the compositions of the reactive and refractory components of DON are largely unknown. Here we show the unique ability of atmospheric pressure photoionization (APPI) coupled to ultrahigh resolution mass spectrometry to identify the reactive and refractory components of DON. Figure 1 is an isolated 0.30 m/z window from an ultrahigh resolution APPI FT-ICR mass spectrum of DON in surface waters draining an agricultural area in South Florida. Using this optimized, negative-ion APPI strategy we have been able to identify the reactive and refractory components of DON in these nitrogen-rich waters. Similar results were observed with samples from soil porewaters in sedge-dominated fens and sphagnum-dominated bogs within the Glacial Lake Agassiz Peatlands (GLAP) of northern Minnesota. Surprisingly, microbes appear to initially use similar enzymatic pathways to degrade DON and DOC, often with little release of nitrogen. Figure 1. Isolated 0.30 m/z window at nominal mass 432 from negative-ion APPI FT-ICR mass spectrum of DOM from waters draining an agricultural area in South Florida. Peaks marked contain nitrogen.

A previously unrecognized path of early Holocene base flow and elevated discharge from Lake Minong to Lake Chippewa across eastern Upper Michigan

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Loope, Walter L.; Jol, Harry M.; Fisher, Timothy G.; Blewett, William L.; Loope, Henry M.; Legg, Robert J.

2014-01-01

It has long been hypothesized that flux of fresh meltwater from glacial Lake Minong in North America's Superior Basin to the North Atlantic Ocean triggered rapid climatic shifts during the early Holocene. The spatial context of recent support for this idea demands a reevaluation of the exit point of meltwater from the Superior Basin. We used ground penetrating radar (GPR), foundation borings from six highway bridges, a GIS model of surface topography, geologic maps, U.S. Department of Agriculture–Natural Resources Conservation Service soils maps, and well logs to investigate the possible linkage of Lake Minong with Lake Chippewa in the Lake Michigan Basin across eastern Upper Michigan. GPR suggests that a connecting channel lies buried beneath the present interlake divide at Danaher. A single optical age hints that the channel aggraded to 225 m as elevated receipt of Lake Agassiz meltwater in the Superior Basin began to wane GIS model of Minong's shoreline are consistent with another transgression of Minong after ca. 9.5 ka. At the peak of the latter transgression, the southeastern rim of the Superior Basin (Nadoway Drift Barrier) failed, ending Lake Minong. Upon Minong's final drop, aggradational sediments were deposited at Danaher, infilling the prior breach.

Diversidade das assembléias de peixes nas quatro unidades geográficas do rio Paraíba do Sul Diversity of fish assemblages in the four geographic units of the Paraíba do Sul river

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Tatiana P. Teixeira

2005-12-01

Full Text Available Padrões na diversidade de peixes ao longo de quatro unidades geográficas (superior, médio-superior, médio-inferior e inferior no rio Paraíba do Sul foram estudados com a finalidade de avaliar tendências de variações espaciais (unidades geográficas e temporais (períodos de cheia e seca. Vinte e cinco locais foram amostrados entre Dezembro de 2002 e Março de 2003 (verão/cheia e, entre Agosto e Novembro de 2003 (inverno/seca. Os peixes foram capturados com um esforço padronizado, utilizando redes de espera, tarrafas e peneiras. Um total de 81 espécies foram registradas compreendendo 9 ordens, 29 famílias e 55 gêneros. Characiformes apresentaram maior número de espécies (28 seguido de Siluriformes (23. Perciformes, principalmente Tilapia rendalli e Geophagus brasiliensis, e Cyprinodontiformes com destaque para Poecilia vivipara e Poecilia reticulata, foram os grupos numericamente mais abundantes, enquanto Siluriformes, principalmente Hypostomus luetkeni, e Perciformes com Geophagus brasiliensis apresentaram maior contribuição em biomassa. Poecilia vivipara foi encontrada apenas no período de seca. Espacialmente, Hoplosternum littorale predominou no trecho médio-superior, Pimelodus fur, Hypostomus luetkeni, Glanidium albescens no trecho médio-inferior, e Loricariichtys spixii e Prochilodus lineatus no trecho inferior. O número de espécies e a riqueza de Margalef apresentaram um aumento do trecho superior para o inferior, principalmente durante o período de cheia. Espécies que apresentaram ampla distribuição ao longo do rio (G. brasiliensis, Oligosarcus hepsetus e P. reticulata são consideradas oportunistas por se aproveitarem dos recursos disponíveis em ambientes pobres, refletindo o estado de alterações do rio. Diferenciações na fisiografia ao longo da extensão longitudinal da bacia não coincidiram com mudanças nas assembléias de peixes, sugerindo que fatores associados a alterações de hábitats poderiam

Geochemical and sedimentological properties of Heinrich layers H2 and H1 off the Hudson Strait ice-surging source areas: ice-rafting vs water-laid down depositional mechanisms

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Nuttin, L.; Hillaire-Marcel, C.

2012-12-01

The ~9 m-long core HU08-029-004PC was raised from the lower Labrador Sea slope (2674 m water-depth), approximately 180 km off Hudson Strait shelf edge. It yielded a high resolution record spanning the last 35 ka. The sequence includes layers with abundant detrital carbonates produced by glacial erosion of Paleozoic rocks and released into the Labrador Sea through ice streaming processes in Hudson Strait and Ungava Bay. These layers are assigned to 'Heinrich events' 3 (at core bottom), 2 and 1. Sedimentological properties and U and Th isotope measurements are used to document depositional mechanisms and durations of these layers. Data suggest: i) intense ice-rafting deposition (IRD) due to iceberg calving at the ice-stream edge, as illustrated by the coarse fraction content of the layers, and ii) sub-glacial meltwater flushing over the Hudson Strait sill, carrying fine silt-size, carbonate-rich glacial flour to the shelf-edge. Such suspended sediment pulses led to the spreading of turbidites mostly into the deep Labrador Sea, through the NAMOC system. Others late-glacial events, such as the ~ 8.2 ka final drainage of Lake Agassiz, are also recorded in the study core, whereas the H0 layer, exclusively observed in the western Labrador Sea is missing. CAT-scan images, mineralogical data, carbonate abundance, %>106 μm fraction (mostly IRD here), U-Th isotope data and 14C ages of planktic foraminifera assemblages (Neogloboquadrina pachyderma, l.) are used to further document H2 (760 to 700 cm) and H1 (588 to 488 cm). The H-layers contain up to 60% of fine detrital carbonates (about 2/3 calcite, 1/3 dolomite). Whereas the fine calcitic material points to sediment sources (basal till/water-laid glacial sediments) in the Hudson Strait and Ungava Bay, i.e., originating from the glacial erosion of Paleozoic carbonates from the area, the dolomitic component might have several origins (from Proterozoic and Paleozoic limestones in the Hudson Bay and Strait, to northwestern

Atividade de amilase em quimo de três espécies tropicais de peixes teleostei de água doce Amylase activity in the chyme of three teleostei freshwater fish

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José Teixeira de Seixas Filho

1999-01-01

Full Text Available O objetivo deste trabalho foi determinar a atividade de amilase no quimo presente nos intestinos médio e posterior, ou reto, em três espécies tropicais de peixes Teleostei de água doce: piracanjuba, Brycon orbignyanus (Valenciennes, 1849, piau, Leporinus friderici (Bloch, 1794, onívoros, e surubim, Pseudoplatystoma coruscans (Agassiz, 1829, preferencialmente carnívoro, visando fornecer referência à nutrição para o ajuste da alimentação artificial. As atividades de amilase foram determinadas usando-se kit BIOCLIN com metodologia modificada por CARAWAY (1959. Os resultados monstraram atividade específica média (2106,33 UA/mg para amilase do piracanjuba e foram 91,74% menor em comparação ao piau (25.488,14 UA/mg, ambos de hábito alimentar onívoro, enquanto a atividade específica da amilase para o piracanjuba foi 89,06% menor em relação ao surubim (19.246,80 UA/mg, carnívoro, o qual apresentou atividade específica da amilase 24,49% menor em relação à do piau. Os dados sugerem que a grande diferença da atividade específica de amilase entre o piau e o piracanjuba possui ligação com sua morfometria e o complexo arranjo das pregas da mucosa dos intestinos médio e posterior. Além disso, a atividade de amilase do surubim indica possibilidade de uso de ração contendo carboidratos, porém estudos adicionais são necessários para a avaliação do comportamento dessas espécies na alimentação artificial.The objective of this work was to determine the amylase activity in the chyme present in the medium and posterior intestines or in the rectum of three tropical freshwater Teleostei species: piracanjuba, Brycon orbignyanus (Valenciennes, 1849, piau, Leporinus friderici (Bloch, 1974, omnivorous, and surubim, Pseudoplatystoma coruscans (Agassiz, 1829, preferably carnivorous, aiming to provide nutritional reference data for the adjustment of the artificial feeding systems. The amylase activity was determined by the use of

PERSPECTIVAS DE SUSTENTABILIDADE ECOLÓGICA DO TURISMO EM XINGÓ, SE/AL / TOURISM ECOLOGICAL SUSTAINABILITY PERSPECTIVES IN XINGÓ, SERGIPE AND ALAGOAS, BRAZIL

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Cláudio Roberto Braghini

2009-06-01

Full Text Available RESUMO A busca da sustentabilidade em várias dimensões implica olhar para o desenvolvimento local nos territórios em que o turismo ocorre. Este estudo analisou de forma sistêmica a relação entre turismo, gastronomia local e os recursos extraídos do rio São Francisco pela pesca artesanal, na região de Xingó, Nordeste do Brasil. A área de estudo abrangeu três municípios, Poço Redondo/SE, Canindé de São Francisco/SE e Piranhas/AL. Tratou-se de uma pesquisa exploratória, descritiva, intencional e não probabilística, utilizando entrevistas com roteiro estruturado e aberto, junto aos restaurantes, pescadores artesanais e gestores públicos, visitas locais de reconhecimento, construção de mapa coletivo com pescadores e elaboração de diagramas de alças causais, visando selecionar indicadores de sustentabilidade. Os resultados indicaram o Surubim Pseudoplatystoma corruscans (Spix e Agassiz, 1829, Pitu Macrobrachium carcinus (Linnaeus, 1758 e Tubarana Salminus hilarii (Valenciennes, 1850, os pescados típicos mais vendidos, no entanto, dependem de distribuidores e de estoques externos. Observou-se que a redução do pescado na região deveu-se à barragem da UHE de Xingó e a sobrepesca. O fluxo turístico crescente tem forte influência sobre o camarão Pitu. Os indicadores ambientais selecionados apontam necessidade de sistematização de informações sobre a produção pesqueira e o consumo nos restaurantes.Palavras-chaves: Sustentabilidade; Turismo; Xingó; Rio São Francisco; CaatingaABSTRACTThe carrying support and the development of the local tourism involve different looks on its dimensions in the area where it occurs. This study examined in a systematic way the sustainability of tourism in the Northeast - Brazil, region of Xingó: the resources tourist and local gastronomy. The study area covers three districts: Poço Redondo and Canindé do São Francisco at Sergipe and in the state of Alagoas at Piranhas. This research

Long-term stability of tidal and diel-related patterns in mangrove creek fish assemblages in North Brazil

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Castellanos-Galindo, G. A.; Krumme, U.

2014-08-01

Intertidal fish assemblages are thought to respond to tidal and diel rhythms although the assumption that these patterns are stable over long time scales (>1 year) is largely untested. Testing the validity of this assumption is necessary to assess whether short-term temporal patterns, once established, can be extrapolated over time and give a better understanding of the temporal dynamics of fish assemblages in coastal habitats. Here, we compare the fish assemblage structure from two intertidal mangrove creeks in North Brazil (Bragança Peninsula, Caeté estuary) sampled with the same sampling methodology (block nets), effort (two lunar cycles) and design (accounting for the combination of tidal and diel cycle) in the rainy seasons of 1999 and 2012 to evaluate the persistence, stability and recurrence of short-term patterns in the fish community organization. The interaction of tidal and diel cycles (inundations at spring tide-night, spring tide-day, neap tide-night, neap tide-day), found to be stable after 13 years, resulted in recurrent and stable intertidal mangrove fish assemblage compositions. The intertidal mangrove creek fish assemblage consisted of a persistent number of dominant species (seven). However, there were notable changes in fish catch mass, abundance and species dominance between 1999 and 2012. The most severe drought in North Brazil in 30 years, linked to lower precipitation and river runoff in the rainy season of 2012, may have resulted in (1) lower abundance of small juveniles of several dominant species in this assemblage (especially Ariidae - Cathorops agassizii and Sciades herzbergii) and (2) increased dominance of large-sized specimens of the tetraodontid Colomesus psittacus. Our findings highlight: (1) the overriding importance and stability of the interactive pulse of the tidal and diel cycles in determining short-term temporal patterns in intertidal mangrove fish assemblages in neotropical macrotidal estuaries despite the occurrence of

Epididymal sperm from Spix's yellow-toothed cavies sperm successfully cryopreserved in Tris extender with 6% glycerol and 20% egg yolk.

Science.gov (United States)

Silva, Andréia M; Praxedes, Erica C G; Campos, Lívia B; Bezerra, Luana G P; Moreira, Samara S J; Maia, Keilla M; Souza, Ana L P; Silva, Alexandre R

2018-04-01

As a non-threatened hystricognath rodent species, Spix's yellow-toothed cavies can be used as a model for the development of assisted reproductive techniques for the conservation of closely related species. The objective was to establish a functional protocol for cryopreservation of epididymal sperm from these cavies. Twelve sexually mature males, ∼2 y old and weighing ∼300 g, were euthanized. Sperm were recovered by retrograde flushing of the vas deferens and cauda epididymis with Tris extender. Thereafter, sperm were extended in Tris plus 20% egg yolk, with 3%, 6% or 9% glycerol or dimethyl sulfoxide (DMSO), placed in 0.25 mL straws and cryopreserved in liquid nitrogen. Sperm concentration, motility (using computer-assisted sperm analysis; CASA), plasma membrane integrity, osmotic response, morphology and sperm binding-ability were determined in fresh and frozen-thawed sperm. For most sperm endpoints, glycerol was a more desirable cryoprotectant than DMSO. Data (mean ± SEM) were similar with use of 3%, 6%, and 9% glycerol (P > 0.05) in osmotic response (40.66 ± 6.3%, 42.5 ± 7.1%, and 39.5 ± 5.0% respectably), and membrane integrity (55.17 ± 5.5%, 68.4 ± 4.1%, and 59.1 ± 4.9% respectably). Among concentrations assessed, the use of 6% glycerol resulted in the greatest (P < 0.05) post-thaw values for total motility (60.9 ± 4.4%), rapid subpopulation motility (27.7 ± 3.1%) and sperm-binding capability (227.0 ± 20.2). In conclusion, epididymal sperm from the Spix's yellow-toothed cavies (G. spixii) are optimally cryopreserved in Tris extender with 6% glycerol and 20% egg yolk. Copyright © 2018 Elsevier B.V. All rights reserved.

Sustained swimming improves fish dietary nutrient assimilation efficiency and body composition of juvenile Brycon amazonicus

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Gustavo Alberto Arbeláez-Rojas

Full Text Available ABSTRACT Sustained swimming (SS usually promotes beneficial effects in growth and feed conversion of fishes. Although feed efficiency is improves at moderate water velocity, more information is required to determine the contributions of this factor on growth and body composition. Body composition and efficiency responses to the use of nutrients were determined in juvenile matrinxa Brycon amazonicus (Spix and Agassiz, 1829 fed with two dietary amounts of protein, 28 or 38% of crude protein (CP, and subjected to sustained swimming at a constant speed of 1.5 body lengths s−1 (BL s−1 or let to free swimming. The fish body composition under SS and fed with 28% of dietary protein showed 22% of increased in bulk protein and a 26% of decrease in water content in the white muscle. Red muscle depicted 70% less water content and a 10% more lipid. Nutrient retention was enhanced in fish subjected to SS and a higher gain of ethereal extract sustained was observed in the white muscle of exercised fish fed with 38% CP. The interaction between swimming and dietary protein resulted in a larger bulk of lipid in red muscle. Fish fed with 28% CP under SS at 1.5 BL s−1 presented the best utilization of dietary nutrients and body composition. Thus, this fish farming procedure is proposed as a promising management strategy for rearing matrinxa.

Factors affecting the thermal environment of Agassiz’s Desert Tortoise (Gopherus agassizii) cover sites in the Central Mojave Desert during periods of temperature extremes

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Mack, Jeremy S.; Berry, Kristin H.; Miller, David; Carlson, Andrea S.

2015-01-01

Agassiz's Desert Tortoises (Gopherus agassizii) spend >95% of their lives underground in cover sites that serve as thermal buffers from temperatures, which can fluctuate >40°C on a daily and seasonal basis. We monitored temperatures at 30 active tortoise cover sites within the Soda Mountains, San Bernardino County, California, from February 2004 to September 2006. Cover sites varied in type and structural characteristics, including opening height and width, soil cover depth over the opening, aspect, tunnel length, and surficial geology. We focused our analyses on periods of extreme temperature: in summer, between July 1 and September 1, and winter, between November 1 and February 15. With the use of multivariate regression tree analyses, we found cover-site temperatures were influenced largely by tunnel length and subsequently opening width and soil cover. Linear regression models further showed that increasing tunnel length increased temperature stability and dampened seasonal temperature extremes. Climate change models predict increased warming for southwestern North America. Cover sites that buffer temperature extremes and fluctuations will become increasingly important for survival of tortoises. In planning future translocation projects and conservation efforts, decision makers should consider habitats with terrain and underlying substrate that sustain cover sites with long tunnels and expanded openings for tortoises living under temperature extremes similar to those described here or as projected in the future.

Larvae of migratory fish (Teleostei: Ostariophysi in the lotic remnant of the Paraná River in Brazil

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Evelyn Barzotto

2015-08-01

Full Text Available ABSTRACT Fish larvae and adults are morphologically distinct from each other and have different ecological requirements. Research on the dynamics of ichthyoplankton provides valuable information about the early stages of the life cycle of fish. This study analyzed the temporal and spatial distribution of the larval stages of three migratory species - Salminus brasiliensis (Cuvier, 1816, Prochilodus lineatus (Valenciennes, 1836 and Pseudoplatystoma corruscans (Agassiz, 1829 - to identify possible spawning areas in the last lotic remnant of the upper Paraná River, in the Brazilian territory. A total of 26 points were sampled monthly from October 2003 to November 2004. The PERMANOVA detected significant differences between the months only for S. brasiliensis (Pseudo-F = 3.88, p = 0.0021 and P. corruscans (Pseudo-F = 3.35, p = 0.004. Among the environmental variables, temperature was the most important and the Mantel test detected a significant correlation between temperature and the densities, only for P. lineatus (r = 0.09, p = 0.03. The species in our data chose for spawning tributaries that are not dammed, of which most are outside conservation areas. Therefore, recruitment, maintenance and possible actions aiming to recover the stocks of these species are dependent on the conservation of tributaries and floodplain lakes in the region, in addition to monitoring to prevent fishing during the reproductive period.

IMPROVEMENT OF METHODS FOR HYDROBIOLOGICAL RESEARCH AND MODIFICATION OF STANDARD TOOLS FOR SAMPLE COLLECTION

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M. M. Aligadjiev

2015-01-01

Full Text Available Aim. The paper discusses the improvement of methods of hydrobiological studies by modifying tools for plankton and benthic samples collecting. Methods. In order to improve the standard methods of hydro-biological research, we have developed tools for sampling zooplankton and benthic environment of the Caspian Sea. Results. Long-term practice of selecting hydrobiological samples in the Caspian Sea shows that it is required to complete the modernization of the sampling tools used to collect hydrobiological material. With the introduction of Azov and Black Sea invasive comb jelly named Mnemiopsis leidyi A. Agassiz to the Caspian Sea there is a need to collect plankton samples without disturbing its integrity. Tools for collecting benthic fauna do not always give a complete picture of the state of benthic ecosystems because of the lack of visual site selection for sampling. Moreover, while sampling by dredge there is a probable loss of the samples, especially in areas with difficult terrain. Conclusion. We propose to modify a small model of Upstein net (applied in shallow water to collect zooplankton samples with an upper inverted cone that will significantly improve the catchability of the net in theCaspian Sea. Bottom sampler can be improved by installing a video camera for visual inspection of the bottom topography, and use sensors to determine tilt of the dredge and the position of the valves of the bucket. 

Turbines and Terrestrial Vertebrates: Variation in Tortoise Survivorship Between a Wind Energy Facility and an Adjacent Undisturbed Wildland Area in the Desert Southwest (USA).

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Agha, Mickey; Lovich, Jeffrey E; Ennen, Joshua R; Augustine, Benjamin; Arundel, Terence R; Murphy, Mason O; Meyer-Wilkins, Kathie; Bjurlin, Curtis; Delaney, David; Briggs, Jessica; Austin, Meaghan; Madrak, Sheila V; Price, Steven J

2015-08-01

With the recent increase in utility-scale wind energy development, researchers have become increasingly concerned how this activity will affect wildlife and their habitat. To understand the potential impacts of wind energy facilities (WEF) post-construction (i.e., operation and maintenance) on wildlife, we compared differences in activity centers and survivorship of Agassiz's desert tortoises (Gopherus agassizii) inside or near a WEF to neighboring tortoises living near a wilderness area (NWA) and farther from the WEF. We found that the size of tortoise activity centers varied, but not significantly so, between the WEF (6.25 ± 2.13 ha) and adjacent NWA (4.13 ± 1.23 ha). However, apparent survival did differ significantly between the habitat types: over the 18-year study period apparent annual survival estimates were 0.96 ± 0.01 for WEF tortoises and 0.92 ± 0.02 for tortoises in the NWA. High annual survival suggests that operation and maintenance of the WEF has not caused considerable declines in the adult population over the past two decades. Low traffic volume, enhanced resource availability, and decreased predator populations may influence annual survivorship at this WEF. Further research on these proximate mechanisms and population recruitment would be useful for mitigating and managing post-development impacts of utility-scale wind energy on long-lived terrestrial vertebrates.

Benthic megafaunal and demersal fish assemblages on the Chilean continental margin: The influence of the oxygen minimum zone on bathymetric distribution

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Quiroga, Eduardo; Sellanes, Javier; Arntz, Wolf E.; Gerdes, Dieter; Gallardo, Victor A.; Hebbeln, Dierk

2009-07-01

Benthic megafaunal and demersal fish assemblages were sampled in three areas off Chile during the German-Chilean Expedition PUCK (SO-156) onboard the R/V Sonne from March to May 2001, at depths ranging from 120 to 2201 m. These samples, taken with an Agassiz trawl, are among the deepest ever taken in Chilean waters. A total of 147 species were recorded, mainly decapod crustaceans (Galatheidae, Pandalidae, Crangonidae), gastropods (Trochidae, Muricidae, Volutidae), ophiuroids (Asteronychidae, Gorgonocephalidae, Ophiolepididae, Ophiurinae), asteroids (Pterasteridae, Solasteridae, Goniopectinidae), polychaetes (Onuphidae, Aphroditidae, Maldanidae), and demersal fish (Macrouridae, Ipnopidae, Squalidae). Species richness and rarefaction analyses suggest that the fauna was undersampled. From the 147 species identified in this study, 36 species (24.5%) occurred only once and another 24 species occurred only twice (16.3%). Depth and dissolved oxygen levels were found to be the main factors influencing megafaunal changes along the continental shelf and in bathyal areas, as indicated by principal component and Pearson's correlation analyses. Some species appear to be limited to distinct areas in the upper and lower bathyal zones, whereas other species have a wider range, extending from the continental shelf to lower bathyal zones. Biogeographic relations exist with the Pacific, South Atlantic, and Southern Oceans, but the latter seem to be weaker than would be expected considering the connection by Antarctic intermediate water.

A potential predator-prey interaction of an American badger and an Agassiz's desert tortoise with a review of badger predation on turtles

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Smith, Amanda L.; Puffer, Shellie R.; Lovich, Jeffrey E.; Tennant, Laura A.; Arundel, Terry; Vamstad, Michael S.; Brundige, Kathleen D.

2016-01-01

The federally threatened Agassiz’s desert tortoise (Gopherus agassizii) was listed under the U.S. Endangered Species Act in 1990, but thus far, recovery efforts have been unsuccessful (U.S. Fish and Wildlife Service [USFWS] 2015). Predation has been identified as a contributing factor to declining G. agassizii populations range-wide (e.g., Esque et al. 2010, Lovich et al. 2014). Understanding and managing for predator-prey dynamics is thus an important part of the recovery and conservation of this threatened species (USFWS 2011). Desert tortoises have a host of predators at all stages of their life cycle. Over 20 species of birds, mammals, and reptiles have been recorded as known or suspected predators (Woodbury and Hardy 1948, Luckenbach 1982, Ernst and Lovich 2009). American badgers (Taxidea taxus, family: Mustelidae) are confirmed excavators of desert tortoise nests (Turner and Berry 1984). They are also suspected predators of adult desert tortoises, a possibility which has been presented in some studies but without empirical verification (Luckenbach 1982, Turner and Berry 1984). Active mostly at night, badgers are solitary, secretive predators (Lindzey 1978, 1982; Armitage 2004) that are extremely difficult to observe in predatory encounters. Recently, strong circumstantial evidence presented by Emblidge et al. (2015) suggests that badgers do prey on adult Agassiz’s desert tortoises based on observations of more than two dozen dead tortoises in the Western Mojave Desert of California. In this note, we present another case of potential badger predation on a large adult desert tortoise in the Sonoran Desert of California. Collectively, these recent two cases potentially indicate that badger predation may be more common and widespread than previously thought. In addition, we review the worldwide literature of badger predation on turtles in general and summarize reported badger observations in Joshua Tree National Park, where our observation occurred, over a period of 55 years.

Comparative study on hematological parameters of farmed matrinxã, Brycon amazonicus Spix and Agassiz, 1829 (Characidae: Bryconinae with others Bryconinae species Estudo comparativo sobre parâmetros hematológicos de matrinxã Brycon amazonicus Spix e Agassiz, 1892(Characidae: Bryconinae criados em cativeiro, com outras espécies de Bryconinae

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Marcos Tavares-Dias

2008-12-01

Full Text Available The aim of this study was not only to determine the red blood cells parameters, thrombocyte and leukocyte counts in farmed Brycon amazonicus (matrinxã, to compare these parameters among Bryconinae species from literature, and also to investigate the presence of special granulocytic cells in these fish. The results of the blood cells parameters here established for farmed B. amazonicus, a species of great economic importance in Brazilian aquaculture, could help a better understanding of the blood features in natural populations of this Amazon species. Blood parameters varied between Bryconinae species investigated, mainly the red blood cell counts, hemoglobin, hematocrit and mean corpuscular volume (MCV. The presence of the blood granulocytes, neutrophils and heterophils in matrinxã suggest that both leukocytes can be a characteristic for Bryconinae family. Furthermore, it indicates that the existence of special granulocytic cells in the blood of Bryconinae species from literature is an artifact, and this was herein discussed.O objetivo deste estudo foi determinar os parâmetros eritrocíticos, as contagens de trombócitos e de leucócitos de espécimes de Brycon amazonicus (matrinxã, criados em cativeiro e compará-los com aqueles descritos na literatura para outras espécies de Bryconinae. Além disso, foi ainda investigada a presença de células granulocíticas especiais nestes peixes. Os resultados dos parâmetros sangüíneos apresentados para B. amazonicus podem ajudar a entender melhor as características sangüíneas em população natural desta espécie de grande importância para a aqüicultura brasileira. Os parâmetros sangüíneos das espécies de Bryconinae investigadas apresentaram variação interespecíficas principalmente a contagem de eritrócitos, hemoglobina, hematócrito e volume corpuscular médio (VCM. A presença dos granulócitos sangüíneos, neutrófilos e heterófilos em matrinxã sugere que esta pode ser uma característica das espécies pertencentes à subfamília Bryconinae. Além disso, indica que a existência de células granulocíticas especiais no sangue de espécies de Bryconinae da literatura é um artefato, e isto foi aqui discutido.

Distribution, feeding and ecomorphology of four species of Auchenipteridae (Teleostei: Siluriformes in Eastern Amazonia, Brazil

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Tiago M. S. Freitas

Full Text Available ABSTRACT Fish exhibit morphological, physiological and behavioral specializations which enable them to display different ways to explore the environments and resources. Thus, the aim of this study was to verify how four Auchenipteridae species differ in the distribution, feeding habits and morphological traits: Auchenipterichthys longimanus (Günther, 1864, Auchenipterus nuchalis (Spix & Agassiz, 1829, Tatia intermedia (Steindachner, 1877 and Trachelyopterus galeatus (Linnaeus, 1766. This study was conducted in rivers and bays of the Anapú Basin, Pará State (Brazil, where these species are abundant. Specimens were collected using gillnets, and after caught the stomachs were removed for the contents analyzes. Eighteen morphometric measurements from ten adult specimens of each species were taken, combined into fifteen ecomorphological attributes. The species distribution showed that A. longimanus was restricted to rivers, while the others were exclusively caught in the bays. All four species had their diet composed of allochthonous insects, but A. longimanus also exhibited a great frugivorous habit. The most important ecomorphological attributes were relative to the consumption of larger food items (for A. longimanus and T. galeatus and to the longer swimming capacity (for A. longimanus and T. intermedia. These morphological differences and the trophic diversity presented in this study highlighted some important information about how ecomorphological similar species behave and share resources, which may play a significant role on the coexistence of these species in the Anapú Basin.

The Acid-Base Balance Between Organic Acids and Circumneutral Ground Waters in Large Peatlands

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Siegel, D. I.; Glaser, P. H.; So, J.

2006-05-01

Organic acids supply most of the acidity in the surface waters of bogs in peatlands. Yet, the fundamental geochemical properties of peatland organic acids are still poorly known. To assess the geochemical properties of typical organic acid assemblages in peatlands, we used a triprotic analog model for peat pore waters and surface waters in the Glacial Lake Agassiz Peatlands, optimizing on charge balance and calibrated to estimates of mole site density in DOC and triprotic acid dissociation constants. Before the calibration process, all bog waters and 76% of fen waters had more than +20% charge imbalance. After calibration, most electrochemically balanced within 20%. In the best calibration, the mole site denisty of bog DOC was estimated as ~0.05 mmol/mmol C., approximately 6 times smaller than that for fen DOC or the DOC in the fen deeper fen peats that underlie bogs. The three modeled de-protonation constants were; pKa1 = ~3.0, pKa2 = ~4.5 and pKa3 = ~7.0 for the bog DOC, and; pKa1 = ~5.2, pKa2 =~ 6.5 and pKa3 = ~7.0 for the fen DOC. Bog DOC, behaves as a strong acid despite its small mole site density. The DOC in bog runoff can therefore theoretically acidify the surface waters in adjacent fens wherever these waters do not receive sufficient buffering alkalinity from active groundwater seepage.

Diferenciação genética entre populações de Pseudoplatystoma corruscans (Agassiz, 1829 (Osteichthyes, Pimelodidae isoladas pelos saltos de Guaíra do rio Paraná Genetic differentiation among populations of Pseudoplatystoma corruscans (Agassiz, 1829 (Osteichthyes, Pimelodidae isolated by the Guaíra Falls in the Paraná River

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Sônia Maria Alves Pinto Prioli

2002-05-01

Full Text Available Os saltos de Guaíra, também denominados Sete Quedas, constituíam até 1982 uma barreira para a dispersão de peixes migradores. Este trabalho teve por objetivo verificar se populações de Pseudoplatystoma corruscans (Osteichthyes, Pimelodidae eram isoladas pelos saltos de Guaíra. Amostras provenientes da planície de inundação do alto rio Paraná (PL, do reservatório Itaipu (IT e de jusante de Yacyretá (YA, foram comparadas por RAPD. O FST de Lynch foi significativo entre PL e IT (0,090 e PL e YA (0,112. O fluxo gênico estimado (Nm variou de 2,0 entre PL e YA a 8,1 entre IT e YA, e a distância genética de Nei de D = 0,0638 entre PL e YA a D = 0,0174 entre IT e YA. Estes resultados indicam existência de diferenciação genética e que, possivelmente, Sete Quedas isolavam reprodutivamente as populações. Sugerem, também, a possibilidade de áreas diferentes de desova, impedindo parcialmente a homogeneização genética das populações IT e PL.Until 1982, the Guaíra Falls, also named the Seven Falls, constituted a barrier to the dispersion of migratory fish in the Paraná River. The objective of this work was to verify if populations of Pseudoplatystoma corruscans (Osteichthyes, Pimelodidae were isolated by the Guaíra Falls. Samples from the Upper Paraná River floodplain (PL, the Itaipu reservoir (IT, and downstream Yacyretá reservoir (YA were compared by RAPD markers. Lynch's FST was significant between PL and IT (0.090, and PL and YA (0.112. Estimated gene flow (Nm varied from 2.0 between PL and YA to 8.1 between IT and YA. Nei's genetic distance varied from D = 0.0638 between PL and YA to D = 0.0174 between IT and YA. These results indicate the existence of genetic differentiation and that, possibly, the Guaíra Falls isolated the populations reproductively. They also suggest the possibility of different spawning areas, partially avoiding the genetic homogenization of the IT and PL populations.

Diversity of Micrurus Snake Species Related to Their Venom Toxic Effects and the Prospective of Antivenom Neutralization

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Tanaka, Gabriela D.; Furtado, Maria de Fátima D.; Portaro, Fernanda C. V.; Sant'Anna, Osvaldo Augusto; Tambourgi, Denise V.

2010-01-01

Background Micrurus snake bites can cause death by muscle paralysis and respiratory arrest, few hours after envenomation. The specific treatment for coral snake envenomation is the intravenous application of heterologous antivenom and, in Brazil, it is produced by horse immunization with a mixture of M. corallinus and M. frontalis venoms, snakes that inhabit the South and Southeastern regions of the country. However, this antivenom might be inefficient, considering the existence of intra- and inter-specific variations in the composition of the venoms. Therefore, the aim of the present study was to investigate the toxic properties of venoms from nine species of Micrurus: eight present in different geographic regions of Brazil (M. frontalis, M. corallinus, M. hemprichii, M. spixii, M. altirostris, M. surinamensis, M. ibiboboca, M. lemniscatus) and one (M. fulvius) with large distribution in Southeastern United States and Mexico. This study also analyzed the antigenic cross-reactivity and the neutralizing potential of the Brazilian coral snake antivenom against these Micrurus venoms. Methodology/Principal Findings Analysis of protein composition and toxicity revealed a large diversity of venoms from the nine Micrurus species. ELISA and Western blot assays showed a varied capability of the therapeutic antivenom to recognize the diverse species venom components. In vivo and in vitro neutralization assays indicated that the antivenom is not able to fully neutralize the toxic activities of all venoms. Conclusion These results indicate the existence of a large range of both qualitative and quantitative variations in Micrurus venoms, probably reflecting the adaptation of the snakes from this genus to vastly dissimilar habitats. The data also show that the antivenom used for human therapy in Brazil is not fully able to neutralize the main toxic activities present in the venoms from all Micrurus species occurring in the country. It suggests that modifications in the

Modeling effects of conservation grassland losses on amphibian habitat

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Mushet, David M.; Neau, Jordan L.; Euliss, Ned H.

2014-01-01

Amphibians provide many ecosystem services valued by society. However, populations have declined globally with most declines linked to habitat change. Wetlands and surrounding terrestrial grasslands form habitat for amphibians in the North American Prairie Pothole Region (PPR). Wetland drainage and grassland conversion have destroyed or degraded much amphibian habitat in the PPR. However, conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining grasslands on agricultural lands. We used an ecosystem services model (InVEST) parameterized for the PPR to quantify amphibian habitat over a six-year period (2007–2012). We then quantified changes in availability of amphibian habitat under various land-cover scenarios representing incremental losses (10%, 25%, 50%, 75%, and 100%) of CRP grasslands from 2012 levels. The area of optimal amphibian habitat in the four PPR ecoregions modeled (i.e., Northern Glaciated Plains, Northwestern Glaciated Plains, Lake Agassiz Plain, Des Moines Lobe) declined by approximately 22%, from 3.8 million ha in 2007 to 2.9 million ha in 2012. These losses were driven by the conversion of CRP grasslands to croplands, primarily for corn and soybean production. Our modeling identified an additional 0.8 million ha (26%) of optimal amphibian habitat that would be lost if remaining CRP lands are returned to crop production. An economic climate favoring commodity production over conservation has resulted in substantial losses of amphibian habitat across the PPR that will likely continue into the future. Other regions of the world face similar challenges to maintaining amphibian habitats.

Climatic drivers for multidecadal shifts in solute transport and methane production zones within a large peat basin

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Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno

2016-01-01

Northern peatlands are an important source for greenhouse gases, but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43 year time series of the pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multidecadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 to 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2 m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Δ14C with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

Climatic Drivers for Multi-Decadal Shifts in Solute Transport and Methane Production Zones within a Large Peat Basin

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Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno

2016-01-01

Northern peatlands are an important source for greenhouse gases but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43-year time series of pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multi-decadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 through 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2 m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Delta C-14 with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

Gopherus agassizii: Desert tortoise

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Berry, Kristen H.; Swingland, Ian Richard; Klemens, Michael W.

1989-01-01

The desert tortoise is one of four allopatric North American tortoises. It occurs in the Mojave and Sonoran deserts of the southwestern United States and Mexico.Auffenberg (1976) divided the genus Gopherus (consisting of four species, G. agassizi, G. berlandieri, G.flavomarginatus, and G. polyphemus) in two osteological groups. Bramble (1982), using morphological and palaeontological data, divided the genus Gopherus into two separate complexes, each with two species. He established a new genus, Scaptochelys, for agassizi and berlandieri, retaining Gopherus for polyphemus and flavomarginatus. Bour and Dubois (1984) noted that Xerobates Agassiz had priority over Scaptochelys Bramble. Using mitochondrial DNA (mtDNA), Lamb et al. (1989) evaluated the evolutionary relationships of the North American tortoises, particularly the desert tortoise. They concluded that the mtDNA analysis provides strong support for generic recognition of the two distinct species groups described by Bramble (1982).Until a few decades ago, the desert tortoise was widespread at lower elevations throughout the Mojave and Sonoran deserts of the U.S.A. In the northern and western parts of the geographic range, large and relatively homogeneous populations with densities exceeding 1,000/sq km extended throughout parts of California, and probably into Nevada and Utah. In terms of biomass, the tortoise played an important role in the ecosystems. In most areas, numbers have declined dramatically and the extent of populations has been reduced. Most populations are now isolated and low in numbers. Conservation of the desert tortoise is a highly visible and political issue in the U.S.A., but not in Mexico.

REDESCRIPTION OF SCIADOCEPHALUS MEGALODISCUS DIESING, 1850, ONE THE EARLIEST DIVERGING NEOTROPICAL FISH TAPEWORMS (CESTODA: PROTEOCEPHALIDAE).

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Scholz, Tomáš; de Chambrier, Alain

2018-06-04

The tapeworm Sciadocephalus megalodiscus Diesing, 1850 (Cestoda: Proteocephalidae) is redescribed based on newly collected specimens parasitizing tucunare peacock bass, Cichla monoculus Agassiz, 1831 (Perciformes: Cichlidae), in the Peruvian Amazon. Even though this cestode was redescribed 2 decades ago by Rego et al. (1999), that redescription did not report some of the unique features of this species. The most unusual characteristics of the species are: (i) peculiar formation of the uterus, with fast formation of numerous, tightly packed diverticula protruding ventrally and dorsally, with simultaneous disintegration of the ovary and vitelline follicles in the first pregravid proglottids; (ii) inverted umbrella-shaped scolex with a well-developed apical sucker; (iii) a large-sized, follicular (grape cluster-like) ovary, which occupies most of the central (median) third of proglottids, with the ovarian isthmus situated almost equatorially; (iv) regular alternation of genital pores; (v) a well-developed internal seminal vesicle; and (vi) a small-sized strobila (shorter than 6 mm) consisting of few proglottids (15-20). Preliminary molecular data reveal S. megalodiscus to be most closely related to Cichlidocestus gillesi, the type species of the recently erected Cichlidocestus de Chambrier, Pinacho-Pinacho, Hernández-Orts and Scholz, 2017. Species of both genera parasitize Neotropical cichlids and are unique among all proteocephalids in the shape and position of the ovary. They also share other morphological characteristics unusual among other proteocephalids and thus these two genera can be considered good candidates to be placed in a new, higher-level taxon such as separate subfamily or even family when a new, more natural classification of the Proteocephalidae is proposed.

Relationships between Molecular Composition and Optical Properties of Dissolved Organic Matter

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Cooper, W. T.; Tfaily, M.; Osborne, D.; Paul, A.; Podgorski, D. C.; Corbett, J.; Chanton, J.

2009-12-01

Our focus is on the relationships between the optical properties of dissolved organic matter (DOM) and its molecular composition. For example, we demonstrated that changes in the absorption and fluorescence characteristics of DOM in outwelling from Brazilian mangrove forests correlated with decreases in highly unsaturated organic compounds as DOM was transported from mangrove porewaters to the continental shelf. In that work we combined ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) that provided detailed compositional information with absorption and Excitation/Emission Matrix (EEM) spectroscopy This presentation will highlight new results utilizing the combination of optical spectroscopy and FT-ICR mass spectrometry to illuminate the processes which control DOM cycling. Our focus will be on the contributions of the heteroatom components of DOM (i.e. organic sulfur and organic nitrogen) to its optical properties and how changes in optical properties correlate with important environmental processes like humification and bioavailability. Figure 1 below includes a narrow 0.20 Dalton window from a mass spectrum which demonstrates the ability of ultrahigh resolution mass spectrometry to resolve and identify nitrogen heteroatom compounds in DOM. Our study sites include the Glacial Lake Agassiz Peatlands (GLAP) in northern Minnesota and wetlands in the Caloosahatchee River basin in South Florida. Figure 1. Isolated 0.20 Da window of an ESI-FT-ICR mass spectrum of DOM from a GLAP bog. Labels identify N1 (d,e,f) and N3 classes of nitrogen heteroatoms. The 0.0031 Da mass spacing is used to confirm the N3 class.

Tapeworms (Cestoda: Proteocephalidea) of firewood catfish Sorubimichthys planiceps (Siluriformes: Pimelodidae) from the Amazon River.

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de Chambrier, Alain; Scholz, Tomás

2008-03-01

A survey of proteocephalidean cestodes found in the firewood catfish Sorubimichthys planiceps (Spix et Agassiz) from the Amazon River is provided. The following taxa parasitic in S. planiceps are redescribed on the basis of their type specimens and material collected recently in the Amazon River, near the type localities in Brazil, and in Iquitos, Peru: Monticellia lenha Woodland, 1933; Nomimoscolex lenha (Woodland, 1933) (syn. Proteocephalus lenha Woodland, 1933); and Monticellia megacephala Woodland, 1934, for which a new genus, Lenhataenia, is proposed, with L. megacephala (Woodland, 1934) comb. n. as its type and only species. The new genus is a member of the Monticelliinae, i.e. has all genital organs in the cortex, and is most similar to Chambriella in possessing biloculate suckers and lacking a metascolex. It differs in the morphology of the cirrus-sac that contains a strongly coiled, thick-walled internal sperm duct (vas deferens) and a muscular cirrus of the appearance typical of most proteocephalideans, whereas that of Chambriella is sigmoid, with voluminous, tightly sinuous thick-walled internal sperm duct. In addition, Lenhataenia possesses a well developed internal musculature, whereas the internal musculature of Chambriella is weakly developed, formed by a low number of muscle fibres. The scolex morphology and distribution of microtriches of Peltidocotyle lenha (Woodland, 1933) (syn. Othinoscolex lenha Woodland, 1933 and Othinoscolex myzofer Woodland, 1933), Chambriella sp. and Choanoscolex sp. are described using scanning electron microscopy. The two latter taxa may be new for science and are reported from S. planiceps for the first time.

Seasonal and spatial variations of macro- and megabenthic community characteristics in two sections of the East China Sea

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Xu, Yong; Li, Xinzheng; Ma, Lin; Dong, Dong; Kou, Qi; Sui, Jixing; Gan, Zhibin; Wang, Hongfa

2017-09-01

In spring and summer 2011, the macro- and megabenthic fauna in two sections of the East China Sea were investigated using an Agassiz net trawl to detect the seasonal and spatial variations of benthic community characteristics and the relation to environmental variables. The total number of species increased slightly from spring (131 species) to summer (133) whereas the percentage of Mollusca decreased significantly. The index of relative importance (IRI) indicated that the top five important species changed completely from spring to summer. Species number, abundance and biomass in summer were significantly higher than in spring, but no significant difference was observed among areas (coastal, transitional and oceanic areas, divided basically from inshore to offshore). Species richness ( d), diversity ( H') and evenness ( J') showed no significant seasonal or spatial variations. Cluster analysis and nMDS ordination identified three benthic communities from inshore to offshore, corresponding to the three areas. Analysis of Similarity (ANOSIM) indicated the overall significant difference in community structure between seasons and among areas. K-dominance curves revealed the high intrinsic diversity in the offshore area. Canonical correspondence analysis showed that the coastal community was positively correlated to total nitrogen and total organic carbon in spring, but negatively in summer; oceanic community was positively correlated to total nitrogen and total organic carbon in both seasons. Species such as Coelorhynchus multispinulosus, Neobythites sivicola, Lepidotrigla alata, Solenocera melantho, Parapenaeus fissuroides, Oratosquilla gonypetes and Spiropagurus spiriger occurred exclusively in the offshore oceanic area and their presence may reflect the influence of the offshore Kuroshio Current.

Science at Harvard University: Historical Perspectives, edited by Clark A. Elliott and Margaret W. Rossiter. Lehigh University Press, Bethlehem, 1992

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Andrew L. Christenson

1992-05-01

Full Text Available This volume contains historical studies of several sciences as practiced at Harvard University. Two of these studies have relevance to the history of archaeology. A chapter by Toby Appel focuses upon the scientific career of Jeffries Wyman, first curator of Harvard's Peabody Museum. She contrasts Wyman's unassuming character with the dominating personality of his mentor and contemporary Louis Agassiz. Trained as a medical doctor, Wyman's main love was zoology, particularly comparative anatomy. In his mid-40s, he encountered his first shell midden and was bitten by the archaeology bug. Soon he was doing pioneering excavation in both New England and Florida. In 1866, he was selected to be the curator of the Peabody Museum, primarily upon his strong museum background but also because of the high regard with which he was held by certain influential people. His selection to this position may have made him America's first professional archaeologist. His principal responsibilities were to collect and display archaeological and ethnological specimens and he made great steps in this direction prior to his death in 1874. Wyman's scientific work was poorly known or studied (he is best noted for having made the first scientific description of the gorilla, in part, Appel argues, because he did not seek acclaim or controversy. His greatest influence was locally through personal interactions with students and colleagues. His archaeological work is only briefly discussed in this and the following article, and there is still much to be written about this man of high character.

Nest site characteristics, nesting movements, and lack of long-term nest site fidelity in Agassiz's desert tortoises at a wind energy facility in southern California

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Lovich, Jeffrey E.; Agha, Mickey; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Bjurlin, Curtis; Ennen, Joshua R.; Arundel, Terry R.; Austin, Meaghan

2014-01-01

Nest site selection has important consequences for maternal and offspring survival and fitness. Females of some species return to the same nesting areas year after year. We studied nest site characteristics, fidelity, and daily pre-nesting movements in a population of Agassiz’s desert tortoises (Gopherus agassizii) at a wind energy facility in southern California during two field seasons separated by over a decade. No females returned to the same exact nest site within or between years but several nested in the same general area. However, distances between first and second clutches within a year (2000) were not significantly different from distances between nests among years (2000 and 2011) for a small sample of females, suggesting some degree of fidelity within their normal activity areas. Environmental attributes of nest sites did not differ significantly among females but did among years due largely to changes in perennial plant structure as a result of multiple fires. Daily pre-nesting distances moved by females decreased consistently from the time shelled eggs were first visible in X-radiographs until oviposition, again suggesting some degree of nest site selection. Tortoises appear to select nest sites that are within their long-term activity areas, inside the climate-moderated confines of one of their self-constructed burrows, and specifically, at a depth in the burrow that minimizes exposure of eggs and embryos to lethal incubation temperatures. Nesting in “climate-controlled” burrows and nest guarding by females relaxes some of the constraints that drive nest site selection in other oviparous species.

Fate and consequence of nutrients at an abandoned feedlot, Glacial Ridge National Wildlife Refuge, Minnesota, USA

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Philip J. Gerla

2018-01-01

Full Text Available Old, abandoned feedlots may serve as a source of nutrients that can degrade groundwater and downstream water quality. We characterized the distribution and concentration of nutrients at the Crookston Cattle Company feedlot (northwest Minnesota, USA, 15 years after it ended operations in 1999. Groundwater nitrate concentration decreased from 55 mg/L (as nitrogen in 2003 to less than 5 mg/L since 2007. Results from stable isotope analysis, with δ15N and δ18O in groundwater nitrate ranging up to +44 and +30‰, respectively, suggest denitrification as the cause, rather than either nitrate transport from the site or dilution. Phosphorus, with soil B-horizon concentrations as much as 112 and averaging 24 mg/kg, is sequestered by carbonate-rich glacial sediments and, serendipitously, an iron-rich sand deposit formed millennia ago by wave action along the shore of glacial Lake Agassiz. Map analysis indicates roughly 20,000 kg of P in excess of background concentration remains in soil at the 15 ha site. Evidence suggests that the former feedlot has not affected water quality significantly in an agricultural ditch that drains the feedlot and its vicinity. Rather than originating from the feedlot, small increases of total phosphorus observed in the downstream ditch likely result from release of phosphorus from nearby recently restored wetlands. More consequential than elevated nutrient concentrations to the future reclamation of this and similar sites is the persistence of robust non-native species. Our results suggest that before development, feedlot sites should be evaluated for their phosphorus sequestration and denitrification potential, thus mitigating the potential for later off-site transport of nutrients.

A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae) from the Late Cretaceous (Santonian-Campanian) of Alabama, USA

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Ehret, Dana J.

2018-01-01

Decades of collecting from exposures of the Upper Cretaceous Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk in Alabama, USA has produced large numbers of isolated Cretalamna (sensu stricto) teeth. Many of these teeth had formerly been assigned to the extinct Late Cretaceous shark Cretalamna appendiculata (Agassiz, 1843), a taxon that is now considered largely restricted to the Turonian of Europe. Recent studies have shed light on the diversity of Late Cretaceous Cretalamna (s.s.) taxa, and here we recognize a new species from Alabama, Cretalamna bryanti. The teeth of C. bryanti sp. nov. appear aligned with the members of the Cretalamna borealis species group, but can be distinguished from these other species by a combination of the following: anterior teeth with a more pronounced and triangular lingual root protuberance, broader triangular cusp, and a taller root relative to the height of the crown; anteriorly situated lateroposterior teeth have a distally inclined or hooked main cusp and more than one pair of lateral cusplets; and lateroposterior teeth have a strong distally hooked main cusp and a root that is largely symmetrical in basal view. At present, C. bryanti sp. nov. is stratigraphically confined to the Santonian/Campanian Dicarinella asymetrica Sigal, 1952 and Globotruncanita elevata Brotzen, 1934 Planktonic Foraminiferal Zones within the Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk, and teeth have been collected from only four counties in central and western Alabama. The recognition of C. bryanti sp. nov. in Alabama adds to our knowledge on the diversity and distribution of Late Cretaceous otodontids in the region. PMID:29333348

An extraordinary gobioid fish fossil from Southern France.

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Christoph Gierl

Full Text Available BACKGROUND: The classification of gobioid fishes is still under discussion. Several lineages, including the Eleotridae and Butidae, remain difficult to characterize because synapomorphies are rare (Eleotridae or have not yet been determined (Butidae. Moreover, the fossil record of these groups is scarce. RESULTS: Exceptionally well-preserved fish fossils with otoliths in situ from uppermost Oligocene sediments (≈23-24 Mio. y. ago in Southern France provide the most in-depth description of a fossil gobioid to date. The species was initially described as Cottus aries Agassiz, then transferred to †Lepidocottus Sauvage, and subsequently assigned to Gobius. Based on a comparative analysis of meristic, osteological and otolith data, this species most likely is a member of the family Butidae. This discovery is important because it represents the first record of a fossil butid fish based on articulated skeletons from Europe. SIGNIFICANCE: The Butidae and Eleotridae are currently distributed in W-Africa, Madagascar, Asia and Australia, but they do not appear in Europe and also not in the Mediterranean Sea. The new results indicate that several species of the Butidae thrived in Europe during the Oligocene and Early Miocene. Similar to the recent Butidae and Eleotridae, these fishes were adapted to a wide range of salinities and thrived in freshwater, brackish and marginal marine habitats. The fossil Butidae disappeared from Europe and the Mediterranean and Paratethys areas during the Early Miocene, due probably to their lack of competitiveness compared to other Gobioidei that radiated during this period of time. In addition, this study documents the great value of otoliths for gobioid systematics.

A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae from the Late Cretaceous (Santonian-Campanian of Alabama, USA

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Jun A. Ebersole

2018-01-01

Full Text Available Decades of collecting from exposures of the Upper Cretaceous Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk in Alabama, USA has produced large numbers of isolated Cretalamna (sensu stricto teeth. Many of these teeth had formerly been assigned to the extinct Late Cretaceous shark Cretalamna appendiculata (Agassiz, 1843, a taxon that is now considered largely restricted to the Turonian of Europe. Recent studies have shed light on the diversity of Late Cretaceous Cretalamna (s.s. taxa, and here we recognize a new species from Alabama, Cretalamna bryanti. The teeth of C. bryanti sp. nov. appear aligned with the members of the Cretalamna borealis species group, but can be distinguished from these other species by a combination of the following: anterior teeth with a more pronounced and triangular lingual root protuberance, broader triangular cusp, and a taller root relative to the height of the crown; anteriorly situated lateroposterior teeth have a distally inclined or hooked main cusp and more than one pair of lateral cusplets; and lateroposterior teeth have a strong distally hooked main cusp and a root that is largely symmetrical in basal view. At present, C. bryanti sp. nov. is stratigraphically confined to the Santonian/Campanian Dicarinella asymetrica Sigal, 1952 and Globotruncanita elevata Brotzen, 1934 Planktonic Foraminiferal Zones within the Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk, and teeth have been collected from only four counties in central and western Alabama. The recognition of C. bryanti sp. nov. in Alabama adds to our knowledge on the diversity and distribution of Late Cretaceous otodontids in the region.

Full-sky survey searching for ultra-narrow-band artificial CW signals: analysis of the results of Project META

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Lemarchand, Guillermo A.

1996-06-01

Project META (Megachannel ExtraTerrestrial Assay), a full-sky survey for artificial narrow-band signals, has been conducted from the Harvard/Smithsonian 26 m radiotelescope at Agassiz Station and from one of the two 30 m radiotelescopes of the Instituto Argentino de Radioastronomia (IAR). The search was performed near the 1420 MHz line of neutral hydrogen, and its second harmonic, using two 8.4 X 10(superscript 6) channel Fourier spectrometers of 0.05 Hz resolution and 400 kHz of instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earth's rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 6 X 10(superscript 13) spectral channels searched in the northern hemisphere, Horowitz and Sagan reported 37 candidates events exceeding the average threshold of 1.7 X 10(superscript -23) W m(superscript -2), while in the southern hemisphere among 2 X 10(superscript 13) spectral channels analyzed we found 19 events exceeding the same threshold. The strongest signals that survive culling for terrestrial interference lie in or near the Galactic Plane. The first high resolution southern target search around 71 stars (-90 degrees intelligence. It is showed that these narrow-band non-repeating 'events' found by Project META can be generated by (a) radiometer noise fluctuations, (b) a population of constant galactic sources which undergo deep fading and amplification due to interstellar scintillation, consistent with ETI transmissions and (c) real, transient signals of either terrestrial or extraterrestrial origin. The Bayesian test shows that hypothesis (b) and (c) are both highly preferred to (a), but the first two are about equally likely. Using this analysis we discuss the best observing strategies to determine the real origin of these 'events'.

Emendation and new species of Hapalorhynchus Stunkard, 1922 (Digenea: Schistosomatoidea) from musk turtles (Kinosternidae: Sternotherus) in Alabama and Florida rivers.

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Roberts, Jackson R; Halanych, Kenneth M; Arias, Cova R; Folt, Brian; Goessling, Jeffrey M; Bullard, Stephen A

2017-12-01

Hapalorhynchus Stunkard, 1922 is emended based on morphological study of existing museum specimens (type and voucher specimens) and newly-collected specimens infecting musk turtles (Testudines: Kinosternidae: Sternotherus spp.) from rivers in Alabama and Florida (USA). Hapalorhynchus conecuhensis n. sp. is described from an innominate musk turtle, Sternotherus cf. minor, (type host) from Blue Spring (31°5'27.64″N, 86°30'53.21″W; Pensacola Bay Basin, Alabama) and the loggerhead musk turtle, Sternotherus minor (Agassiz, 1857) from the Wacissa River (30°20'24.73″N, 83°59'27.56″W; Apalachee Bay Basin, Florida). It differs from congeners by lacking a body constriction at level of the ventral sucker, paired anterior caeca, and a transverse ovary as well as by having a small ventral sucker, proportionally short posterior caeca, nearly equally-sized anterior and posterior testes, a small cirrus sac, and a uterus extending dorsal to the ovary and the anterior testis. Specimens of Hapalorhynchus reelfooti Byrd, 1939 infected loggerhead musk turtles, stripe-necked musk turtles (Sternotherus peltifer Smith and Glass, 1947), Eastern musk turtles (Sternotherus odoratus [Latreille in Sonnini and Latreille, 1801]), and S. cf. minor. Those of Hapalorhynchus cf. stunkardi infected S. minor and S. odoratus. Sternothorus minor, S. peltifer, and S. cf. minor plus S. minor and S. odoratus are new host records for H. reelfooti and H. cf. stunkardi, respectively. This is the first report of an infected musk turtle from the Coosa and Tallapoosa Rivers (Mobile-Tensaw River Basin), Pensacola Bay Basin, or Apalachee Bay Basin. Sequence analysis of the large subunit rDNA (28S) showed a strongly-supported clade for Hapalorhynchus. Copyright © 2017 Elsevier B.V. All rights reserved.

Composition and Dynamics of the Nucleolinus, a Link between the Nucleolus and Cell Division Apparatus in Surf Clam (Spisula) Oocytes*

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Alliegro, Mark C.; Hartson, Steven; Alliegro, Mary Anne

2012-01-01

The nucleolinus is a little-known cellular structure, discovered over 150 years ago (Agassiz, L. (1857) Contributions to the Natural History of the United States of America, First Monograph, Part IIL, Little, Brown and Co., Boston) and thought by some investigators in the late 19th to mid-20th century to function in the formation of the centrosomes or spindle. A role for the nucleolinus in formation of the cell division apparatus has recently been confirmed in oocytes of the surf clam, Spisula solidissima (Alliegro, M. A., Henry, J. J., and Alliegro, M. C. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 13718–13723). However, we know so little about the composition and dynamics of this compartment, it is difficult to construct mechanistic hypotheses or even to be sure that prior reports were describing analogous structures in the cells of mammals, amphibians, plants, and other organisms where it was observed. Surf clam oocytes are an attractive model to approach this problem because the nucleolinus is easily visible by light microscopy, making it accessible by laser microsurgery as well as isolation by common cell fractionation techniques. In this report, we analyze the macromolecular composition of isolated Spisula nucleolini and examine the relationship of this structure to the nucleolus and cell division apparatus. Analysis of nucleolinar RNA and protein revealed a set of molecules that overlaps with but is nevertheless distinct from the nucleolus. The proteins identified were primarily ones involved in nucleic acid metabolism and cell cycle regulation. Monoclonal antibodies generated against isolated nucleolini revealed centrosomal forerunners in the oocyte cytoplasm. Finally, induction of damage to the nucleolinus by laser microsurgery altered the trafficking of α- and γ-tubulin after fertilization. These observations strongly support a role for the nucleolinus in cell division and represent our first clues regarding mechanism. PMID:22219192

Genetic divergence between Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Siluriformes: Pimelodidae in the Paraná River Basin

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TS. Bignotto

Full Text Available Pseudoplatystoma corruscans (Spix and Agassiz, 1829 and Pseudoplatystoma reticulatum (Eingenmann and Eigenmann, 1889 are large migratory catfishes of high biological importance and great commercial value in South America. Because fertile crossbreeds can be artificially produced in hatcheries, a high genetic proximity between these two Pimelodidae species is conceivable. Possible escape of crossbred specimens from pisciculture stations is a serious environmental concern. Despite their importance, knowledge of P. corruscans and P. reticulatum biology, ecology, population diversity and genetics is limited. In the present work, the genetic divergence between P. corruscans and P. reticulatum populations from the Paraná River Basin was analyzed on the basis of polymorphisms in ISSR fragments and in the hypervariable sequence of the mitochondrial DNA (mtDNA control region. Estimates of intraspecific haplotype (h > 0.5 and nucleotide diversities (π < 0.01 indicate that P. corruscans and P. reticulatum have survived a historical population decline, followed by a demographic expansion. The interspecific polymorphisms within the mtDNA control region and ISSR fragments were suitable as diagnostic molecular markers and could be used to discriminate the two species. A unique Pseudoplatystoma specimen, captured in the Upper Paraná River Floodplain, was identified by these DNA diagnostic markers as a hybrid P. reticulatum x P. corruscans, which possibly escaped from pisciculture. The integrity of the natural population of P. corruscans in the Upper Paraná River is at risk of genetic introgression or homogenization due to the presence of hybrids and the transposition of P. reticulatum upstream through the Canal da Piracema at Itaipu Dam. Data presented herein improve the understanding of the genetic relatedness between P. corruscans and P. reticulatum and represent potential tools for future programs of conservation and surveillance of genetic introgression

Seasonal variation of macromedusae (Cnidaria at North Bay, Florianópolis, southern Brazil

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Miodeli Nogueira Júnior

2010-06-01

Full Text Available Seasonal variation of large medusae abundance and biomass was studied in the North Bay, Santa Catarina, southern Brazil (27°30'S, 48° 32'W, from February to December 2005. Collecting was conducted seasonally with the help of fishing bottom trawl in 30-minute sections (12 in summer, 18 in each of the remaining seasons in six stations, totaling 66 samples. Eight species were found: the hydrozoans Aequorea sp., Olindias sambaquiensis Müller, 1861, and Rhacostoma atlantica L. Agassiz, 1850; the cubozoans Chiropsalmus quadrumanus (Müller, 1859 and Tamoya haplonema Müller, 1859, and the scyphozoans Aurelia sp., Chrysaora lactea Eschscholtz, 1829 and Lychnorhiza lucerna Haeckel, 1880. Capture rates were low, up to 38 indiv. ha-1, and only ~47% of the samples were positive for jellyfish, comprising 206 individuals. Medusae abundance and species richness clearly changed from one season to another, but did not vary between the sites. Higher species richness (7 out of 8 and greater abundances were recorded during the fall (~60% and 72% of all medusae individuals and biomass respectively. Specific frequency of capture varied from 1.5 to 29% and C. lactea was the only species found in more than 25% of the samples. The three most common species dominated in different periods of the year: C. lactea during fall (78% of individuals and 60% of biomass, R. atlantica during winter (90% of individuals and 17% of biomass, and O. sambaquiensis in spring (78% of individuals and 40% of biomass. Only two individuals were caught during summer, one C. lactea and one R. atlantica. The results offer a general picture of the distribution of the macromedusae in the North Bay, but a continuous monitoring is desirable for a more detailed knowledge on the jellyfish dynamics in the Brazilian coastal waters.

Mapping of marine benthic invertebrates in the Oslofjord and the Skagerrak: sampling data of museum collections from 1950-1955 and from recent investigations

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Eivind Oug

2015-12-01

Full Text Available Data from large sampling programmes for the mapping of marine invertebrates in the Oslofjord, Norway, and the Skagerrak, spanning more than six decades, are compiled and digitized to provide easy access in modern data repositories. Two sampling programmes undertaken in the period 1950–55 are still the most extensive mapping of marine benthic fauna in the area. Information from a total of more than 900 localities, or sampling events, covering all benthic habitats in the Oslofjord and coastal waters to Kvitsøy in Rogaland county, have been carefully digitized from field notes, original sea charts, and primary observations from sample handling in the field. Geographical coordinates referred to WGS84 chart datum have been fixed with a general accuracy of 20 m in the Oslofjord and 100–250 m in coastal areas, based on precise map sketches with cross-bearings to land objects and chart annotations. Most samples were collected using triangular, Agassiz and lightweight dredges. The collected material has been deposited in the collections of the Natural History Museum, University of Oslo. Two recent projects, ‘Polyskag’ and ‘Bioskag’ (2006–2014, are briefly described. The projects focused on the diversity of marine bristle worms (Polychaeta, inter alia providing material for molecular genetic analyses. Type localities for early described species and generally understudied biotopes were visited. The data from the 1950s, together with recent studies, constitute a considerable resource for studies of biodiversity, facilitated through the sharing of species records from the museum collections in modern data repositories. The accurate positioning of sampling localities in the 1950s is of particular value for documenting species distributions over long time spans, thus providing a reference base for studying present and future species changes and assessing the effects of human influence and environmental changes in the Oslofjord and the Skagerrak.

Not putting all their eggs in one basket: bet-hedging despite extraordinary annual reproductive output of desert tortoises

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Lovich, Jeffrey E.; Ennen, Joshua R.; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Agha, Mickey; Loughran, Caleb L.; Bjurlin, Curtis; Austin, Meaghan; Madrak, Sheila V.

2015-01-01

Bet-hedging theory makes the counter-intuitive prediction that, if juvenile survival is low and unpredictable, organisms should consistently reduce short-term reproductive output to minimize the risk of reproductive failure in the long-term. We investigated the long-term reproductive output of an Agassiz's desert tortoise (Gopherus agassizii) population and conformance to a bet-hedging strategy of reproduction in an unpredictable but comparatively productive environment. Most females reproduced every year, even during periods of low precipitation and poor germination of food plants, and the mean percentage of reproducing females did not differ significantly on an annual basis. Although mean annual egg production (clutch size × clutch frequency) differed significantly among years, mean clutch size and mean clutch frequency remained relatively constant. During an El Niño year, mean annual egg production and mean annual clutch frequency were the highest ever reported for this species. Annual egg production was positively influenced by maternal body size but clutch size and clutch frequency were not. Our long-term results confirm earlier conclusions based on short-term research that desert tortoises have a bet-hedging strategy of producing small clutches almost every year. The risk of long-term reproductive failure is minimized in unpredictable environments, both through time by annually producing multiple small clutches over a long reproductive lifespan, even in years of low resource availability, and through space by depositing multiple annual clutches in different locations. The extraordinary annual reproductive output of this population appears to be the result of a typically high but unpredictable biomass of annual food plants at the site relative to tortoise habitat in dryer regions. Under the comparatively productive but unpredictable conditions, tortoises conform to predictions of a bet-hedging strategy of reproduction with relatively small but consistent

Potential of a Northern Population of Aedes vexans (Diptera: Culicidae) to Transmit Zika Virus.

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O'Donnell, Kyle L; Bixby, Mckenzie A; Morin, Kelsey J; Bradley, David S; Vaughan, Jefferson A

2017-09-01

Zika virus is an emerging arbovirus of humans in the western hemisphere. With its potential spread into new geographical areas, it is important to define the vector competence of native mosquito species. We tested the vector competency of Aedes vexans (Meigen) from the Lake Agassiz Plain of northwestern Minnesota and northeastern North Dakota. Aedes aegypti (L.) was used as a positive control for comparison. Mosquitoes were fed blood containing Zika virus and 2 wk later were tested for viral infection and dissemination. Aedes vexans (n = 60) were susceptible to midgut infection (28% infection rate) but displayed a fairly restrictive midgut escape barrier (3% dissemination rate). Cofed Ae. aegypti (n = 22) displayed significantly higher rates of midgut infection (61%) and dissemination (22%). To test virus transmission, mosquitoes were inoculated with virus and 16-17 d later, tested for their ability to transmit virus into fluid-filled capillary tubes. Unexpectedly, the transmission rate was significantly higher for Ae. vexans (34%, n = 47) than for Ae. aegypti (5%, n = 22). The overall transmission potential for Ae. vexans to transmit Zika virus was 1%. Because of its wide geographic distribution, often extreme abundance, and aggressive human biting activity, Ae. vexans could serve as a potential vector for Zika virus in northern latitudes where the conventional vectors, Ae. aegypti and Ae. albopictus Skuse, cannot survive. However, Zika virus is a primate virus and humans are the only amplifying host species in northern latitudes. To serve as a vector of Zika virus, Ae. vexans must feed repeatedly on humans. Defining the propensity of Ae. vexans to feed repeatedly on humans will be key to understanding its role as a potential vector of Zika virus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Composition and dynamics of the nucleolinus, a link between the nucleolus and cell division apparatus in surf clam (Spisula) oocytes.

Science.gov (United States)

Alliegro, Mark C; Hartson, Steven; Alliegro, Mary Anne

2012-02-24

The nucleolinus is a little-known cellular structure, discovered over 150 years ago (Agassiz, L. (1857) Contributions to the Natural History of the United States of America, First Monograph, Part IIL, Little, Brown and Co., Boston) and thought by some investigators in the late 19th to mid-20th century to function in the formation of the centrosomes or spindle. A role for the nucleolinus in formation of the cell division apparatus has recently been confirmed in oocytes of the surf clam, Spisula solidissima (Alliegro, M. A., Henry, J. J., and Alliegro, M. C. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 13718-13723). However, we know so little about the composition and dynamics of this compartment, it is difficult to construct mechanistic hypotheses or even to be sure that prior reports were describing analogous structures in the cells of mammals, amphibians, plants, and other organisms where it was observed. Surf clam oocytes are an attractive model to approach this problem because the nucleolinus is easily visible by light microscopy, making it accessible by laser microsurgery as well as isolation by common cell fractionation techniques. In this report, we analyze the macromolecular composition of isolated Spisula nucleolini and examine the relationship of this structure to the nucleolus and cell division apparatus. Analysis of nucleolinar RNA and protein revealed a set of molecules that overlaps with but is nevertheless distinct from the nucleolus. The proteins identified were primarily ones involved in nucleic acid metabolism and cell cycle regulation. Monoclonal antibodies generated against isolated nucleolini revealed centrosomal forerunners in the oocyte cytoplasm. Finally, induction of damage to the nucleolinus by laser microsurgery altered the trafficking of α- and γ-tubulin after fertilization. These observations strongly support a role for the nucleolinus in cell division and represent our first clues regarding mechanism.

Parameterization of a complex landscape for a sediment routing model of the Le Sueur River, southern Minnesota

Science.gov (United States)

Belmont, P.; Viparelli, E.; Parker, G.; Lauer, W.; Jennings, C.; Gran, K.; Wilcock, P.; Melesse, A.

2008-12-01

Modeling sediment fluxes and pathways in complex landscapes is limited by our inability to accurately measure and integrate heterogeneous, spatially distributed sources into a single coherent, predictive geomorphic transport law. In this study, we partition the complex landscape of the Le Sueur River watershed into five distributed primary source types, bluffs (including strath terrace caps), ravines, streambanks, tributaries, and flat,agriculture-dominated uplands. The sediment contribution of each source is quantified independently and parameterized for use in a sand and mud routing model. Rigorous modeling of the evolution of this landscape and sediment flux from each source type requires consideration of substrate characteristics, heterogeneity, and spatial connectivity. The subsurface architecture of the Le Sueur drainage basin is defined by a layer cake sequence of fine-grained tills, interbedded with fluvioglacial sands. Nearly instantaneous baselevel fall of 65 m occurred at 11.5 ka, as a result of the catastrophic draining of glacial Lake Agassiz through the Minnesota River, to which the Le Sueur is a tributary. The major knickpoint that was generated from that event has propagated 40 km into the Le Sueur network, initiating an incised river valley with tall, retreating bluffs and actively incising ravines. Loading estimates constrained by river gaging records that bound the knick zone indicate that bluffs connected to the river are retreating at an average rate of less than 2 cm per year and ravines are incising at an average rate of less than 0.8 mm per year, consistent with the Holocene average incision rate on the main stem of the river of less than 0.6 mm per year. Ongoing work with cosmogenic nuclide sediment tracers, ground-based LiDAR, historic aerial photos, and field mapping will be combined to represent the diversity of erosional environments and processes in a single coherent routing model.

Distance to human populations influences epidemiology of respiratory disease in desert tortoises

Science.gov (United States)

Berry, Kristin H.; Ashley A. Coble (formerly Emerson), no longer USGS; Yee, Julie L.; Mack, Jeremy S.; Perry, William M.; Anderson, Kemp M.; Brown, Mary B.

2014-01-01

We explored variables likely to affect health of Agassiz's desert tortoises (Gopherus agassizii) in a 1,183-km2 study area in the central Mojave Desert of California between 2005 and 2008. We evaluated 1,004 tortoises for prevalence and spatial distribution of 2 pathogens, Mycoplasma agassizii and M. testudineum, that cause upper respiratory tract disease. We defined tortoises as test-positive if they were positive by culture and/or DNA identification or positive or suspect for specific antibody for either of the two pathogens. We used covariates of habitat (vegetation, elevation, slope, and aspect), tortoise size and sex, distance from another test-positive tortoise, and anthropogenic variables (distances to roads, agricultural areas, playas, urban areas, and centroids of human-populated census blocks). We used both logistic regression models and regression trees to evaluate the 2 species of Mycoplasma separately. The prevalence of test-positive tortoises was low: 1.49% (15/1,004) for M. agassizii and 2.89% (29/1,004) for M. testudineum. The spatial distributions of test-positive tortoises for the 2 Mycoplasma species showed little overlap; only 2 tortoises were test-positive for both diseases. However, the spatial distributions did not differ statistically between the 2 species. We consistently found higher prevalence of test-positive tortoises with shorter distances to centroids of human-populated census blocks. The relationship between distance to human-populated census blocks and tortoises that are test-positive for M. agassizii and potentially M. testudineum may be related to release or escape of captive tortoises because the prevalence of M. agassizii in captive tortoises is high. Our findings have application to other species of chelonians where both domestic captive and wild populations exist. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

[New settlers comb jellies Mnemiopsis leidyi (A. Agassiz) and Beroe ovata Mayer 1912 and their influence on the pelagic ecosystem of the northeastern part of the Black Sea].

Science.gov (United States)

Shiganova, T A; Musaeva, E I; Bulgakova, Iu V; Mirzoian, Z A; MartynIuk, M L

2003-01-01

We analyzed the condition of pelagic ecosystem of northeastern Black Sea influenced by expansion of a new settler Beroe ovata in 1999-2001. Expansion of B. ovata considerably decreased the population of another new settler Mnemiopsis leidyi that deformed the Black Sea ecosystem for over a decade. Reduction of M. leidyi population limited its influence on the ecosystem and, consequently, we observed reestablishment of the main components of the Black Sea pelagic ecosystem--zooplankton and fish, their spawn and larvae. The relationship between annual and seasonal variability of the population and biomass of the both new settlers M. leidyi and B. ovata are discussed.

A new species of Leporinus Agassiz, 1829 from the upper Rio Paraná basin (Characiformes, Anostomidae with redescription of L. elongatus Valenciennes, 1850 and L. obtusidens (Valenciennes, 1837

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Heraldo A. Britski

2012-01-01

Full Text Available Leporinus obtusidens Valenciennes, 1837 and L. elongatus Valenciennes, 1850 are redescribed based on the type specimens, including those of their junior synonyms, and recently collected specimens. Leporinus obtusidens is considered to be widespread, occuring in the river drainages of La Plata, São Francisco, and Parnaíba. Leporinus aguapeiensis Campos, 1945, described from the upper Rio Paraná, and L. silvestrii Boulenger, 1902, described from the Rio Paraguay, are considered junior synonyms of L. obtusidens. Leporinus elongatus is endemic to the Rio Jequitinhonha and Rio Pardo, two eastern Brazilian river basins, and the locality cited for the lectotype, Rio São Fransico, likely to be erroneous. Leporinus crassilabris Borodin, 1929, and L. crassilabris breviceps Borodin, 1929, both described from the Rio Jequitinhonha, are considered junior synynoms of L. elongatus. A new species of Leporinus, endemic to the upper Rio Paraná, very similar and sometimes mistaken with L. obtusidens, is formally described. In addition, comments on Leporinus pachyurus Valenciennes, 1850 and on L. bimaculatus Castelnau, 1855 are provided, and a lectotype for L. bimaculatus is selected.

Differences in Ca2+-management between the ventricle of two species of neotropical teleosts: the jeju, Hoplerythrinus unitaeniatus (Spix & Agassiz, 1829, and the acara, Geophagus brasiliensis (Quoy & Gaimard, 1824

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Monica Jones Costa

Full Text Available This study analyzed the physiological role of the cardiac sarcoplasmic reticulum (SR of two neotropical teleosts, the jeju, Hoplerythrinus unitaeniatus (Erythrinidae, and the acara, Geophagus brasiliensis (Cichlidae. While the in vivo heart frequency (fH - bpm of acara (79.6 ± 6.6 was higher than that of the jeju (50.3 ± 2.7, the opposite was observed for the ventricular inotropism (Fc - mN/mm² at 12 bpm (acara = 28.66 ± 1.86 vs. jeju = 36.09 ± 1.67. A 5 min diastolic pause resulted in a strong potentiation of Fc (≅ 90% of strips from jeju, which was completely abolished by ryanodine. Ryanodine also resulted in a ≅ 20% decrease in the Fc developed by strips from jeju at both subphysiological (12 bpm and physiological (in vivo frequencies. However, this effect of ryanodine reducing the Fc from jeju was completely compensated by adrenaline increments (10-9 and 10-6 M. In contrast, strips from acara were irresponsive to ryanodine, irrespective of the stimulation frequency, and increases in adrenaline concentration (to 10-9 and 10-6 M further increased Fc. These results reinforce the hypothesis of the functionality of the SR as a common trait in neotropical ostariophysian (as jeju, while in acanthopterygians (as acara it seems to be functional mainly in 'athletic' species.

Fossil isotope records of seasonal climate and ecology: Straight from the horse's mouth

Science.gov (United States)

Sharp, Z. D.; Cerling, T. E.

1998-03-01

Isotope analysis of a bulk fossil tooth gives a “snapshot” impression of paleoclimatic conditions—a single point in time. However, hypsodont teeth grow over a period of a year or more, so that stable carbon and oxygen isotope variations along their length are a “tape recorder” of short-term seasonal variations from the distant past. We have used a new in situ micro-laser sampling method to determine submillimeter carbon and oxygen isotope variations in the enamel of individual fossil horse teeth to assess ancient annual meteoric water variations and feeding patterns. The δ18O values from a 6.8 Ma fossil horse tooth (Astrohippus ansae) from Texas vary cyclically along the 6 cm length of the tooth with a smoothed amplitude of >4‰, similar to the monthly averaged amplitude measured in modern meteoric waters from the region. The seasonal δ18O values are ˜3‰ to 4‰ higher than those calculated from modern meteoric water data, suggesting either a higher local meteoric water value in the Miocene of Texas, or that the animal received a high proportion of its dietary water from plants or highly evaporated water. A Holocene horse tooth from the shores of Glacial Lake Agassiz, North Dakota (Equus sp.), also has isotopic variations with the same 35 mm periodicity, but a smoothed amplitude of only 2‰. This horse most likely had a buffered drinking supply. The calculated δ18O of the water in equilibrium with this tooth is the same as the modern measured annual average. The variations within a single tooth can be as large as those generally observed in entire stratigraphic sections of fossil teeth analyzed by bulk methods. The new method provides an important technique for evaluating fossil diagenesis; conventional bulk analyses of teeth fragments may not be representative of the whole tooth, thus explaining analytical scatter that has been previously attributed to diagenesis.

Spatiotemporal patterns of the macrofaunal community structure in the East China Sea, off the coast of Zhejiang, China, and the impact of the Kuroshio Branch Current.

Science.gov (United States)

Xu, Yong; Yu, Fei; Li, Xinzheng; Ma, Lin; Dong, Dong; Kou, Qi; Sui, Jixing; Gan, Zhibin; Gong, Lin; Yang, Mei; Wang, Yueyun; Sun, Yue; Wang, Jinbao; Wang, Hongfa

2018-01-01

The Kuroshio Current intrudes in the bottom layer of the East China Sea continental shelf from the northeast of Taiwan via two bottom branches named the Nearshore Kuroshio Branch Current (NKBC, along the 60 m isobath) and the Offshore Kuroshio Branch Current (OKBC, along the 100 m isobath). However, knowledge on the macrofaunal responses to these bottom branches is limited. This study examined the variations in the benthic macrofaunal community in a section of the East China Sea under the influence of the NKBC. Seven sites corresponding to three regions (the west, middle and east region) were sampled using an Agassiz trawl net at a monthly rate from February to November 2015 (except in August). A total of 270 macrofaunal species were collected in this study. Cluster analysis and nMDS ordination revealed three communities: the inshore, Kuroshio and offshore communities, roughly corresponding to the west, middle and east of NKBC route. Significant differences in the species composition (one-way PERMANOVA) and diversity indices (one-way ANOVA) among the regions and communities were observed, while no statistically significant difference among the months was detected. The indicator species also varied among the communities, with Sternaspis scutata and Odontamblyopus rubicundus dominating the inshore community, Camatopsis rubida, Schizaster lacunosus and Craspidaster hesperus dominating the Kuroshio community, and Portunus argentatus, Champsodon snyderi and Coelorinchus multispinulosus dominating the offshore community. Some rare species (e.g., Neobythites sivicola) may indicate the passage of the NKBC better than the indicator species. A redundancy analysis was used to describe the relationship between the macrofaunal species and environmental variables in this study. Water depth and turbidity played important roles in the distribution of the macrofauna. S. scutata and O. rubicundus were associated with high turbidity and shallow depth, while Plesionika izumiae and P

Deglaciation, lake levels, and meltwater discharge in the Lake Michigan basin

Science.gov (United States)

Colman, Steven M.; Clark, J.A.; Clayton, L.; Hansel, A.K.; Larsen, C.E.

1994-01-01

The deglacial history of the Lake Michigan basin, including discharge and routing of meltwater, is complex because of the interaction among (1) glacial retreats and re-advances in the basin (2) the timing of occupation and the isostatic adjustment of lake outlets and (3) the depositional and erosional processes that left evidence of past lake levels. In the southern part of the basin, a restricted area little affected by differential isostasy, new studies of onshore and offshore areas allow refinement of a lake-level history that has evolved over 100 years. Important new data include the recognition of two periods of influx of meltwater from Lake Agassiz into the basin and details of the highstands gleaned from sedimentological evidence. Major disagreements still persist concerning the exact timing and lake-level changes associated with the Algonquin phase, approximately 11,000 BP. A wide variety of independent data suggests that the Lake Michigan Lobe was thin, unstable, and subject to rapid advances and retreats. Consequently, lake-level changes were commonly abrupt and stable shorelines were short-lived. The long-held beliefs that the southern part of the basin was stable and separated from deformed northern areas by a hinge-line discontinuity are becoming difficult to maintain. Numerical modeling of the ice-earth system and empirical modeling of shoreline deformation are both consistent with observed shoreline tilting in the north and with the amount and pattern of modern deformation shown by lake-level gauges. New studies of subaerial lacustrine features suggest the presence of deformed shorelines higher than those originally ascribed to the supposed horizontal Glenwood level. Finally, the Lake Michigan region as a whole appears to behave in a similar manner to other areas, both local (other Great Lakes) and regional (U.S. east coast), that have experienced major isostatic changes. Detailed sedimentological and dating studies of field sites and additional

Habitats and landscapes associated with bird species in a lowland conifer-dominated ecosystem

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Edmund J. Zlonis

2017-06-01

Full Text Available Human-induced effects on lowland conifer forests in hemiboreal regions are increasing because of expanded use of these northern ecosystems for raw materials, energy, and minerals as well as the potential effects of climatic changes. These forests support many breeding bird species across the Holarctic and allow the persistence of several boreal bird species in hemiboreal and even temperate regions. These bird species are of particular conservation concern as shifting patterns northward in forest composition caused by climate change will likely affect their populations. However, effective management and conservation options are limited because the specifics of these species' breeding habitats are not well understood. We modeled and mapped habitat suitability for 11 species of boreal birds that breed in the lowland conifer forests of the Agassiz Lowlands Ecological Subsection in northern Minnesota and are likely to have reduced breeding habitat in the future: Spruce Grouse (Falcipennis canadensis, Black-backed Woodpecker (Picoides arcticus, Olive-sided Flycatcher (Contopus cooperi, Yellow-bellied Flycatcher (Empidonax flaviventris, Boreal Chickadee (Poecile hudsonicus, Golden-crowned Kinglet (Regulus satrapa, Ruby-crowned Kinglet (Regulus calendula, Swainson's Thrush (Catharus ustulatus, Connecticut Warbler (Oporornis agilis, Palm Warbler (Setophaga palmarum, and Dark-eyed Junco (Junco hyemalis. Sets of 7 to 16 potential environmental covariates, including both stand-level and landscape attributes, were used to develop individual species models. Within this lowland conifer-dominated ecosystem, we found significant selection for specific forest and landscape characteristics by all but one of these species, with the best models including between one and nine variables. Habitat suitability maps were developed from these models and predictions tested with an independent dataset. Model performance depended on species, correctly predicting 56-96% of

Backfill formulations for a nuclear fuel waste disposal vault

International Nuclear Information System (INIS)

Yong, R.N.; Boonsinsuk, P.; Wong, G.; Ming, X.D.; Caporuscio, F.; Lytle, P.

1987-01-01

Atomic Energy of Canada Limited and Ontario Hydro are studying the concept of disposing of nuclear fuel wastes in a vault within the Canadian Shield. After nuclear waste containers have been emplaced in a vault, the vault will have to be backfilled permanently. A suitable backfill material should have low hydraulic conductivity and high radionuclide sorption capacity. The research was done with a goal of recommending a specification for formulating this backfill material. This report suggests that such a backfill material should be a mixture of coarse aggregates and swelling clay. Actual trial mixtures were prepared using crushed granite and natural Lake Agassiz clay. Various trial mixtures were subjected to constant-head permeability tests. The results indicate that the hydraulic conductivity of the aggregate-clay mixtures could be close to those of the clay (by itself) when the clay content was in the range of 25% or more. The resulting hydraulic conductivity of about 10 -10 m/s is considered to be low, especially since the maximum grain size is 19.1 mm. Selected mixtures were evaluated for free swell and swelling pressure, both of which increased with increasing clay content. When the clay content was 25%, the free swell was about 4%, compared with 6% for the 100% clay. The corresponding swelling pressure was about 16 kPa - in comparison to 48 kPa for the 100% clay. These results indicate that the proposed backfill material should contain about 25% clay, with a maximum grain size of 19.1 mm. The selected mixture was also tested to evaluate the effects of mixing methods, load-carrying capacity and compaction techniques suitable for the underground vault conditions. The proposed backfill material appeared to perform satisfactorily according to the criteria demanded. The backfill material proposed was further tested for its behaviour during water intake. The unsaturated hydraulic conductivity was found to be approximately 10 -10 m/s and the swelling pressure was

Nomenclatural Studies Toward a World List of Diptera Genus-Group Names. Part V: Pierre-Justin-Marie Macquart.

Science.gov (United States)

Evenhuis, Neal L; Pape, Thomas; Pont, Adrian C

2016-09-30

synonymy: Czernyola Bezzi, 1907, n. stat. [Clusiidae].        Names previously treated as available but found in this work to be unavailable include the following: Genus-group names-Anodontina Macquart, 1838, n. stat. [Empididae]; Athricia Macquart, 1834, n. stat. [Tachinidae]; Blepharis Macquart, 1838, n. stat. [Asilidae]; Dichelocera Enderlein, 1922, n. stat. [Tabanidae]; Lepidoselaga Loew, 1869, n. stat. [Tabanidae]; Lemptopeza Macquart, 1828, n. stat. [Hybotidae]; Microphora Zetterstedt, 1842, n. stat. [Dolichopodidae]; Microphorus Macquart, 1834, n. stat. [Dolichopodidae]; Plagiocephala Macquart, 1844, n. stat. [Ulidiidae]; Stratiomyia Macquart, 1838, n. stat. [Stratiomyidae]; Taenioptera Agassiz, 1846, n. stat. [Micropezidae]; Tapigaster Bezzi, 1923, n. stat. [Heleomyzidae]; Trizota Macquart, 1829, n. stat. [Syrphidae]. Species-group names-Microstylum sinense Macquart, 1838, n. stat. [Asilidae].        Corrected or clarified included species and/or corrected or clarified type-species and methods of typification are given for: Anabarhynchus Macquart, 1848 [Therevidae]; Anacanthella Macquart, 1855 [Stratiomyidae]; Apeilesis Macquart, 1846 [Tipulidae]; Aplomera Macquart, 1838 [Empididae]; Aprotheca Macquart, 1851 [Tachinidae]; Ardoptera Macquart, 1828 [Empididae]; Blepharella Macquart, 1851 [Tachinidae]; Brachystylum Macquart, 1855 [Tachinidae]; Cadicera Macquart, 1855 [Tabanidae]; Calobatemyia Macquart, 1855 [Calliphoridae]; Catapicephala Macquart, 1851 [Calliphoridae]; Ceroptera Macquart, 1835 [Sphaeroceridae]; Cheligaster Macquart, 1835 [Sepsidae]; Chetogaster Macquart, 1851 [Tachinidae]; Chlorogaster Macquart, 1851 [Tachinidae]; Cleitamia Macquart, 1835 [Platystomatidae]; Craspedia Macquart, 1838 [Asilidae]; Craspedochoeta Macquart, 1851 [Anthomyiidae]; Crumomyia Macquart, 1835 [Sphaeroceridae]; Dasyomma Macquart, 1840 [Athericidae]; Demoticus Macquart, 1854 [Tachinidae]; Epicerella Macquart, 1851 [Pyrgotidae]; Epicerina Macquart, 1850 [Acroceridae

Spatiotemporal patterns of the macrofaunal community structure in the East China Sea, off the coast of Zhejiang, China, and the impact of the Kuroshio Branch Current.

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Yong Xu

Full Text Available The Kuroshio Current intrudes in the bottom layer of the East China Sea continental shelf from the northeast of Taiwan via two bottom branches named the Nearshore Kuroshio Branch Current (NKBC, along the 60 m isobath and the Offshore Kuroshio Branch Current (OKBC, along the 100 m isobath. However, knowledge on the macrofaunal responses to these bottom branches is limited. This study examined the variations in the benthic macrofaunal community in a section of the East China Sea under the influence of the NKBC. Seven sites corresponding to three regions (the west, middle and east region were sampled using an Agassiz trawl net at a monthly rate from February to November 2015 (except in August. A total of 270 macrofaunal species were collected in this study. Cluster analysis and nMDS ordination revealed three communities: the inshore, Kuroshio and offshore communities, roughly corresponding to the west, middle and east of NKBC route. Significant differences in the species composition (one-way PERMANOVA and diversity indices (one-way ANOVA among the regions and communities were observed, while no statistically significant difference among the months was detected. The indicator species also varied among the communities, with Sternaspis scutata and Odontamblyopus rubicundus dominating the inshore community, Camatopsis rubida, Schizaster lacunosus and Craspidaster hesperus dominating the Kuroshio community, and Portunus argentatus, Champsodon snyderi and Coelorinchus multispinulosus dominating the offshore community. Some rare species (e.g., Neobythites sivicola may indicate the passage of the NKBC better than the indicator species. A redundancy analysis was used to describe the relationship between the macrofaunal species and environmental variables in this study. Water depth and turbidity played important roles in the distribution of the macrofauna. S. scutata and O. rubicundus were associated with high turbidity and shallow depth, while Plesionika

Environmental response to the cold climate event 8200 years ago as recorded at Hoejby Soe, Denmark

Energy Technology Data Exchange (ETDEWEB)

Rasmussen, Peter (Geological Survey of Denmark and Greenland, Copenhagen (Denmark)); Ulfeldt Hede, M.; Noe-Nygaard, N. (Univ. of Copenhagen, Dept. of Geography and Geology, Copenhagen (Denmark)); Clarke, A.L. (APEM Manchester Lab., Stockport (United Kingdom)); Vinebrooke, R.D. (Univ. of Alberta, Dept. of Biological Science - Freshwater Biodiversity Lab., Edmonton (Canada))

2008-07-15

The need for accurate predictions of future environmental change under conditions of global warming has led to a great interest in the most pronounced climate change known from the Holocene: an abrupt cooling event around 8200 years before present (present = A.D. 1950), also known as the '8.2 ka cooling event' (ka = kilo-annum = 1000 years). This event has been recorded as a negative delta18OMICRON excursion in the central Greenland ice cores (lasting 160 years with the lowest temperature at 8150) and in a variety of other palaeoclimatic archives including lake sediments, ocean cores, speleothems, tree rings, and glacier oscillations from most of the Northern Hemisphere. In Greenland the maximum cooling was estimated to be 6 +- 2 deg. C while in southern Fennoscandia and the Baltic countries pollenbased quantitative temperature reconstructions indicate a maximum annual mean temperature decrease of around 1.5 deg. C. Today there is a general consensus that the primary cause of the cooling event was the final collapse of the Laurentide ice sheet near Hudson Bay and the associated sudden drainage of the proglacial Lake Agassiz into the North Atlantic Ocean around 8400 B.P. . This freshwater outflow, estimated to amount to c. 164,000 km3 of water, reduced the strength of the North Atlantic thermohaline circulation and thereby the heat transported to the North Atlantic region, resulting in an atmospheric cooling. The climatic consequences of this meltwater flood are assumed to be a good geological analogue for future climate-change scenarios, as a freshening of the North Atlantic is projected by almost all global-warming models and is also currently being registered in the region. In an ongoing project, the influence of the 8.2 ka cooling event on a Danish terrestrial and lake ecosystem is being investigated using a variety of biological and geochemical proxy data from a sediment core extracted from Hojby So, north-west Sjaelland. Here we present data on

Reducing uncertainty in Climate Response Time Scale by Bayesian Analysis of the 8.2 ka event

Science.gov (United States)

Lorenz, A.; Held, H.; Bauer, E.; Schneider von Deimling, T.

2009-04-01

cold climate event 8200 years ago by meltwater outburst from lake Agassiz. Paleoceanography 19:PA3014, (2004) [2] T. Schneider von Deimling, H. Held, A. Ganopolski, S. Rahmstorf, Climate sensitivity estimated from ensemble simulations of glacial climates, Climate Dynamics 27, 149-163, DOI 10.1007/s00382-006-0126-8 (2006). [3] A. Lorenz, Diploma Thesis, U Potsdam (2007).

New insights into the abyssal sponge fauna of the Kurile-Kamchatka plain and Trench region (Northwest Pacific)

Science.gov (United States)

Downey, Rachel V.; Janussen, Dorte

2015-01-01

-enclosed seas of Japan and Okhotsk. The importance of the dominant sub-Polar Gyre currents, the vast area of abyssal plain and similar levels of productivity, are likely to be driving the strong faunal connectivity in the North Pacific. The importance of utilising several forms of sampling equipment has been illustrated in this study, with half of all specimens caught with non-AGT (Agassiz trawl) equipment.

The genera of Nematinae (Hymenoptera, Tenthredinidae

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Marko Prous

2014-10-01

Full Text Available Recent phylogenetic studies on Nematinae based on DNA sequences have shown extensive incongruencies with current nomenclature of genus-group taxa. Here, we expand previous DNA sequence datasets based on three genes (CoI, Cytb, and EF-1α, to include a fourth (NaK and more genera. The analyses largely confirm the previous findings, particularly the existence of two well-supported large clades, Euura and Pristiphora, together comprising more than 75% of the species of Nematinae. Basal relationships within these two clades remain poorly resolved, mirroring the difficulties in delimiting genera based on morphology. In addition, a moderately supported small clade, Nematus, is found. The relationships between the Euura, Pristiphora, and Nematus clades are uncertain. Therefore, to stabilize the nomenclature we treat these clades as genera. This taxonomic treatment results in numerous new combinations of species names. The following synonymies are proposed for the available genus-group names. Synonyms of Euura Newman, 1837: Cryptocampus Hartig, 1837, Euura Agassiz, 1848, Pontania Costa, 1852, syn. n., Epitactus Förster, 1854, syn. n., Amauronematus Konow, 1890, syn. n., Holcocneme Konow, 1890, syn. n., Pachynematus Konow, 1890, syn. n., Holcocnema Schulz, 1906, syn. n., Holcocnemis Konow, 1907, syn. n., Pteronidea Rohwer, 1911, syn. n., Pontopristia Malaise, 1921, syn. n., Brachycoluma Strand, 1929, syn. n., Decanematus Malaise, 1931, syn. n., Pikonema Ross, 1937, syn. n., Phyllocolpa Benson, 1960, syn. n., Eitelius Kontuniemi, 1966, syn. n., Gemmura E.L. Smith, 1968, Eupontania Zinovjev, 1985, syn. n., Larinematus Zhelochovtsev, 1988, syn. n., Polynematus Zhelochovtsev, 1988, syn. n., Bacconematus Zhelochovtsev, 1988, syn. n., Alpinematus Lacourt, 1996, syn. n., Epicenematus Lacourt, 1998, syn. n., Kontuniemiana Lacourt, 1998, syn. n., Lindqvistia Lacourt, 1998, syn. n., Luea Wei and Nie, 1998, syn. n., and Tubpontania Vikberg, 2010, syn. n. Synonyms

Coeficientes de digestibilidade aparente da proteína e energia de alguns ingredientes utilizados em dietas para o pintado (Pseudoplatystoma coruscans Apparent digestibility coefficients of protein and energy of some ingredients used in diets for pintado, Pseudoplatystoma coruscans (Agassiz, 1829

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Emílio Guedes Gonçalves

2003-08-01

Full Text Available O presente trabalho foi desenvolvido com o objetivo de determinar os coeficientes de digestibilidade aparente da proteína e da energia dos principais alimentos utilizados na formulação de dietas para alevinos de pintado. Foram utilizados 600 alevinos com peso médio inicial de 9,80 ± 1,48 g e comprimento total médio de 13,00 ± 1,00 cm. Na coleta de fezes, foi utilizado o sistema de Guelph modificado. As 12 dietas-teste foram constituídas por 69,50% de uma dieta de referência, 0,50% de óxido de cromo (marcador inerte e 30% do ingrediente estudado. Após receberem as dietas teste durante três dias, os peixes foram transferidos para os aquários de coleta (incubadoras de fibra de vidro de 80 litros de capacidade, onde as fezes foram coletadas em intervalos de meia hora. Com base nos coeficientes de digestibilidade da fração protéica, os alimentos que apresentaram maior aproveitamento para esse nutriente foram: farinha de peixe (84,14%, farelo de soja (67,10%, milho (64,18% e farinha de vísceras de aves (61,25%. Foram observados valores razoáveis somente para a digestibilidade do conteúdo energético em metade dos ingredientes estudados; para as farinhas de peixe, milho, soja integral tostada e os farelos de soja, de trigo e de arroz, os coeficientes médios foram: 72,80; 57,39; 64,95; 61,66; 53,20 e 51,84%, respectivamente. A farinha de peixe foi o melhor ingrediente para o pintado (45,38% PD e 2790,42 kcal ED/kg, seguido do farelo de soja (30,86% PD e 2708,45 kcal ED/kg, da soja integral tostada (18,34% PD e 3121,06 kcal ED/kg, do milho (5,86% PD e 2691,53 kcal ED/kg e do farelo de trigo (8,08% PD e 2265,13 kcal ED/kg.The present work was developed in order to determine the protein and energy apparent digestibility coefficients of the principal ingredients used in the pintado juvenile diets. Six hundred juveniles with initial weight and total length means of 9.80 ± 1.48 g and 13.00 ± 1.00 cm, respectively, were used. The modified Guelph system was appraised to collect feces. All the twelve test diets were constituted of 69.50% of the reference diet, 0.50% of chromium oxide used as inert marker, and 30% of the ingredient tested. After three days of feeding with the test diets, fish were transferred to the collect aquariums, where feces were collected in intervals of 30 minutes. Using digestibility of the protein, ingredients with best results in this nutrient were fish meal (84.14%, soybean meal (67.10%, corn (64.18% and chicken poultry by-product (61.25%. Was only observed reasonable values for energy digestibility in half of the ingredients tested; for fish meal, corn, soybean (whole, toasted and soybean meal of wheat and rice, the mean coefficients values were: 72.80, 57.39, 64.95, 61.66, 53.20, and 51.84%, respectively. Fish meal was the best ingredient available for pintado juveniles diet formulation (45.38%DP and 2790.42 kcal DE/kg, followed by soybean meal (30.86%DP and 2708.45 kcal DE/kg, soybean (whole, toasted (18.34%DP and 3121.06 kcal DE/kg, corn (5.86%DP and 2691.53 kcal DE/kg, and wheat meal (8.08%DP and 2265.13 kcal DE/kg.

Tracking sediment through the Holocene: Determining anthropogenic contributions to a sediment-rich agricultural system, north-central USA

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Gran, Karen; Belmont, Patrick; Finnegan, Noah

2013-04-01

Management and restoration of sediment-impaired streams requires quantification of sediment sources and pathways of transport. Addressing the role of humans in altering the magnitude and sources of sediment supplied to a catchment is notoriously challenging. Here, we explore how humans have amplified erosion in geomorphically-sensitive portions of the predominantly-agricultural Minnesota River basin in north-central USA. In the Minnesota River basin, the primary sources of sediment are classified generally as upland agricultural field vs. near-channel sources, with near-channel sources including stream banks, bluffs, and ravines. Using aerial lidar data, repeat terrestrial lidar scans of bluffs, ravine monitoring, historic air photo analyses, and sediment fingerprinting, we have developed a sediment budget to determine the relative importance of each source in a tributary to the Minnesota River, the Le Sueur River. We then investigate how these sources have changed through time, from changes evident over the past few decades to changes associated with valley evolution over the past 13,400 years. The Minnesota River valley was carved ~13,400 years ago through catastrophic drainage of glacial Lake Agassiz. As the Minnesota River valley incised, knickpoints have migrated upstream into tributaries, carving out deep valleys where the most actively eroding near-channel sediment sources occur. The modern sediment budget, closed for the time period 2000 to 2010, shows that the majority of the fine sediment load in the Le Sueur River comes from bluffs and other near-channel sources in the deeply-incised knick zone. Numerical modeling of valley evolution constrained by mapped and dated strath terraces cut into the glacial till presents an opportunity to compare the modern sediment budget to that of the river prior to anthropogenic modification. This comparison reveals a natural background or "pre-agriculture" rate of erosion from near-channel sources to be 3-5 times lower

Antarctic Starfish (Echinodermata, Asteroidea) from the ANDEEP3 expedition.

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Danis, Bruno; Jangoux, Michel; Wilmes, Jennifer

2012-01-01

This dataset includes information on sea stars collected during the ANDEEP3 expedition, which took place in 2005. The expedition focused on deep-sea stations in the Powell Basin and Weddell Sea.Sea stars were collected using an Agassiz trawl (3m, mesh-size 500µm), deployed in 16 stations during the ANTXXII/3 (ANDEEP3, PS72) expedition of the RV Polarstern. Sampling depth ranged from 1047 to 4931m. Trawling distance ranged from 731 to 3841m. The sampling area ranges from -41°S to -71°S (latitude) and from 0 to -65°W (longitude). A complete list of stations is available from the PANGAEA data system (http://www.pangaea.de/PHP/CruiseReports.php?b=Polarstern), including a cruise report (http://epic-reports.awi.de/3694/1/PE_72.pdf).The dataset includes 50 records, with individual counts ranging from 1-10, reaching a total of 132 specimens.The andeep3-Asteroidea is a unique dataset as it covers an under-explored region of the Southern Ocean, and that very little information was available regarding Antarctic deep-sea starfish. Before this study, most of the information available focused on starfish from shallower depths than 1000m. This dataset allowed to make unique observations, such as the fact that some species were only present at very high depths (Hymenaster crucifer, Hymenaster pellucidus, Hymenaster praecoquis, Psilaster charcoti, Freyella attenuata, Freyastera tuberculata, Styrachaster chuni and Vemaster sudatlanticus were all found below -3770m), while others displayed remarkable eurybathy, with very high depths amplitudes (Bathybiaster loripes (4842m), Lysasterias adeliae (4832m), Lophaster stellans (4752m), Cheiraster planeta (4708m), Eremicaster crassus (4626m), Lophaster gaini (4560m) and Ctenodiscus australis (4489m)).Even if the number of records is relatively small, the data bring many new insights on the taxonomic, bathymetric and geographic distributions of Southern starfish, covering a very large sampling zone. The dataset also brings to light six

Detrital Carbonate Events on the Labrador Shelf, a 13 to 7 kyr Template for Freshwater Forcing From the Laurentide Ice Sheet

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Jennings, A. E.; Andrews, J. T.

2008-12-01

associated with the carbonate spikes suggest that at least some of the meltwater was released by icebergs. Age estimates of these peaks are: 11.5, 10.6, 9.5, 9.1, 8.7, and 8.2 cal kyr BP, and their duration ranges between 50 and 200 years. A 'red bed' is associated with a subsidiary carbonate spike 8.57 cal ka, very close to the estimated age of the timing of the final outburst drainage of lakes Agassiz and Ojibway: about 8.47 cal ka BP. A lower carbonate spike at 11.1 cal ka is associated with a light isotope event. The carbonate record of MD99-2236 promises to be an important key to the timing and role of deglacial episodes in freshwater forcing on North Altantic climate.

Is there a distinct continental slope fauna in the Antarctic?

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Kaiser, Stefanie; Griffiths, Huw J.; Barnes, David K. A.; Brandão, Simone N.; Brandt, Angelika; O'Brien, Philip E.

2011-02-01

The Antarctic continental slope spans the depths from the shelf break (usually between 500 and 1000 m) to ˜3000 m, is very steep, overlain by 'warm' (2-2.5 °C) Circumpolar Deep Water (CDW), and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the abyssal fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell Sea and Scotia Sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III, BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ (Ecology of the Antarctic Sea Ice Zone) II cruises as well as current databases (SOMBASE, SCAR-MarBIN), four different taxa were selected (i.e. cheilostome bryozoans, isopod and ostracod crustaceans and echinoid echinoderms) and two areas, the Weddell Sea and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations. Benthic samples were collected using Agassiz trawl, epibenthic sledge and Rauschert sled. By bathymetric definition, these data suggest that despite eurybathy in some of the groups examined and apparent similarity of physical conditions in the Antarctic, the shelf, slope and abyssal faunas were clearly separated in the Weddell Sea. However, no such separation of faunas was apparent in the Scotia Sea (except in echinoids). Using a geomorphological definition of the slope, shelf-slope-abyss similarity only changed significantly in the bryozoans. Our results did not support the presence of a homogenous and unique Antarctic slope fauna despite a high number of species being restricted to the slope. However, it remains the case that there may be

Present and past Gulf Stream variability in a cold-water coral area off Cape Lookout, West Atlantic

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Mienis, F.; Pedersen, A.; Duineveld, G.; Seidenkrantz, M.; Fischel, A.; Matos, L.; Bane, J. M.; Frank, N.; Hebbeln, D.; Ross, S.

2012-12-01

point at Gulfstream water moving over the deployment site as was confirmed by satellite images. The instantaneous increases in of the turbidity at the onset of warm events when the current speed increases, likely represent local erosion of the seafloor and of the coral mounds. Based on the foraminifera data three zones could be observed in the piston core (13000-10000 years, 10000-7200 years and 7200-4700 years. All zones show the gradual onshore movement of the Gulf Stream, which can be related to a rapid rise in sea-level after the last deglaciation. This movement has gradually widened the band of the Gulfstream thereby compressing the surface and deeper water masses. Current speed in the area are generally strong but weakened during periods of fresh water outflow in the North Atlantic, which weakened the thermohaline circulation. This was especially clear in zone 2 around 8200 years, due to a melt water pulse of lake Agassiz and Ojibway. Data presented here show that the Gulf Stream influenced cold-water coral growth and mound formation at the SE Us margin at present as well as in the past.

Discoveries and Conservation Efforts of Extensive Deep-Sea Coral Habitat off the Southeastern U.S.

Science.gov (United States)

Reed, J. K.; Messing, C. G.; Walker, B. K.; Farrington, S.; Brooke, S.; Correa, T.; Brouwer, M.

2012-12-01

The deep-sea floor of the Western Atlantic off the southeastern U.S. supports a variety of deep-sea coral ecosystem (DSCE) habitats, including: coral mounds, rock terraces (Miami and Pourtalès Terraces), canyons (Agassiz and Tortugas Valleys), and island slopes (western Bahamas and northern Cuba). We used NOAA bathymetric contour maps and digital elevation models to identify and delineate the areal extent of potential DSCE habitat (50-1000 m) from northeastern Florida through the Straits of Florida. Recently, shipboard and AUV side-scan and multibeam sonar have further documented portions of the region. The resulting maps have been ground-truthed with over 250 submersible and remotely operated vehicle (ROV) dives, revealing that high-relief topographic features, including steep escarpments and rocky terraces, are good predictors of DSCE habitat in this region. The benthic biota is diverse but locally variable; for example, Lophelia and Enallopsammia stony corals dominate the deep-water mounds, whereas stylasterid corals dominate the rocky terraces where Lophelia is sporadic. Octocorals, black corals, and sponges are common at most sites but different species exhibit site-specific distributional variability. In 2011, the first of two NOAA-sponsored cruises using sonar mapping and an ROV discovered the southernmost Lophelia coral mound in the continental United States, south of the Florida Keys, offering the possibility that more Lophelia mounds may exist in this region where they were previously thought to be absent. The second cruise discovered that deep-water Oculina varicosa coral reefs extend over 70 nmi north of the current boundaries of the Oculina Habitat Area of Particular Concern (OHAPC), which was first designated as a marine protected area in 1984. These studies indicate that cold-water coral mounds are significantly more diverse and abundant in this region than previously thought. These research results were presented to NOAA and the South Atlantic

Family-group names in Coleoptera (Insecta)

Science.gov (United States)

Bouchard, Patrice; Bousquet, Yves; Davies, Anthony E.; Alonso-Zarazaga, Miguel A.; Lawrence, John F.; Lyal, Chris H. C.; Newton, Alfred F.; Reid, Chris A. M.; Schmitt, Michael; Ślipiński, S. Adam; Smith, Andrew B. T.

2011-01-01

Gistel, 1856 (type species Ptilinus costatus Gyllenhal, 1827, designated herein) syn. nov. of Ptilinus Geoffroy, 1762 (Ptinidae), Paniscus Gistel, 1848 (type species Scarabaeus fasciatus Linnaeus, 1758, designated herein) syn. nov. of Trichius Fabricius, 1775 (Scarabaeidae), Phibalus Gistel, 1856 (type species Chrysomela pubescens Linnaeus, 1758, by monotypy) syn. nov. of Omophlus Dejean, 1834 (Tenebrionidae). The following new replacement name is proposed: Gompeliina Bouchard, 2011 nom. nov. for Olotelina Báguena Corella, 1948 (Aderidae). Reversal of Precedence (Article 23.9) is used to conserve usage of the following names (family-group names followed by genus-group names): Perigonini Horn, 1881 nom. protectum over Trechicini Bates, 1873 nom. oblitum (Carabidae), Anisodactylina Lacordaire, 1854 nom. protectum over Eurytrichina LeConte, 1848 nom. oblitum (Carabidae), Smicronychini Seidlitz, 1891 nom. protectum over Desmorini LeConte, 1876 nom. oblitum (Curculionidae), Bagoinae Thomson, 1859 nom. protectum over Lyprinae Gistel 1848 nom. oblitum (Curculionidae), Aterpina Lacordaire, 1863 nom. protectum over Heliomenina Gistel, 1848 nom. oblitum (Curculionidae), Naupactini Gistel, 1848 nom. protectum over Iphiini Schönherr, 1823 nom. oblitum (Curculionidae), Cleonini Schönherr, 1826 nom. protectum over Geomorini Schönherr, 1823 nom. oblitum (Curculionidae), Magdalidini Pascoe, 1870 nom. protectum over Scardamyctini Gistel, 1848 nom. oblitum (Curculionidae), Agrypninae/-ini Candèze, 1857 nom. protecta over Adelocerinae/-ini Gistel, 1848 nom. oblita and Pangaurinae/-ini Gistel, 1856 nom. oblita (Elateridae), Prosternini Gistel, 1856 nom. protectum over Diacanthini Gistel, 1848 nom. oblitum (Elateridae), Calopodinae Costa, 1852 nom. protectum over Sparedrinae Gistel, 1848 nom. oblitum (Oedemeridae), Adesmiini Lacordaire, 1859 nom. protectum over Macropodini Agassiz, 1846 nom. oblitum (Tenebrionidae), Bolitophagini Kirby, 1837 nom. protectum over Eledonini Billberg, 1820

Family-Group Names In Coleoptera (Insecta

Directory of Open Access Journals (Sweden)

Patrice Bouchard

2011-04-01

Ptilinus costatus Gyllenhal, 1827, designated herein syn. n. of Ptilinus Geoffroy, 1762 (Ptinidae, Paniscus Gistel, 1848 (type species Scarabaeus fasciatus Linnaeus, 1758, designated herein syn. n. of Trichius Fabricius, 1775 (Scarabaeidae, Phibalus Gistel, 1856 (type species Chrysomela pubescens Linnaeus, 1758, by monotypy syn. n. of Omophlus Dejean, 1834 (Tenebrionidae. The following new replacement name is proposed: Gompeliina Bouchard, 2011 nom. n. for Olotelina Báguena Corella, 1948 (Aderidae. Reversal of Precedence (Article 23.9 is used to conserve usage of the following names (family-group names followed by genus-group names: Perigonini Horn, 1881 nom. protectum over Trechicini Bates, 1873 nom. oblitum (Carabidae, Anisodactylina Lacordaire, 1854 nom. protectum over Eurytrichina LeConte, 1848 nom. oblitum (Carabidae, Smicronychini Seidlitz, 1891 nom. protectum over Desmorini LeConte, 1876 nom. oblitum (Curculionidae, Bagoinae Thomson, 1859 nom. protectum over Lyprinae Gistel 1848 nom. oblitum (Curculionidae, Aterpina Lacordaire, 1863 nom. protectum over Heliomenina Gistel, 1848 nom. oblitum (Curculionidae, Naupactini Gistel, 1848 nom. protectum over Iphiini Schönherr, 1823 nom. oblitum (Curculionidae, Cleonini Schönherr, 1826 nom. protectum over Geomorini Schönherr, 1823 nom. oblitum (Curculionidae, Magdalidini Pascoe, 1870 nom. protectum over Scardamyctini Gistel, 1848 nom. oblitum (Curculionidae, Agrypninae/-ini Candèze, 1857 nom. protecta over Adelocerinae/-ini Gistel, 1848 nom. oblita and Pangaurinae/-ini Gistel, 1856 nom. oblita (Elateridae, Prosternini Gistel, 1856 nom. protectum over Diacanthini Gistel, 1848 nom. oblitum (Elateridae, Calopodinae Costa, 1852 nom. protectum over Sparedrinae Gistel, 1848 nom. oblitum (Oedemeridae, Adesmiini Lacordaire, 1859 nom. protectum over Macropodini Agassiz, 1846 nom. oblitum (Tenebrionidae, Bolitophagini Kirby, 1837 nom. protectum over Eledonini Billberg, 1820 nom. oblitum (Tenebrionidae, Throscidae Laporte, 1840 nom

Climatic Controls on the Porewater Chemistry of Mid-Continental Wetlands

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Levy, Zeno Francis

Wetlands develop where climate and physiography conspire to maintain saturated soils at the land surface, support diverse plant and animal communities, and serve as globally important sinks for atmospheric carbon. The chemistry of wetland porewaters impacts near-surface biological communities and subsurface biogeochemical processes that influence carbon cycling in the environment. Wetland porewater chemistry is a dynamic byproduct of complex hydrogeological processes that cause meteoric waters to enter groundwater systems (recharge) or groundwater to flow to the land surface (discharge). Changes in climate can alter subsurface hydraulic gradients that determine the recharge and discharge functions of wetlands, which in turn control the hydrogeochemical evolution of wetland porewaters. The climate of mid-continental North America is influenced by competing air masses with vastly different temperature and moisture contents originating from the Pacific Coast, the Gulf of Mexico, and the Arctic. The interactions of these air masses result in large dynamic shifts of climate regimes characterized by decadal-scale oscillations between periods of drought and heavy rain. Over the course of the 20th century, a shift occurred towards wetter climate in the mid-continental region. This dissertation examines the impact of this climate shift on the porewater chemistry of two very different wetland systems, located only 350 km apart: the Glacial Lake Agassiz Peatlands (GLAP) of northern Minnesota and the Cottonwood Lake Study Area (CLSA) of North Dakota. The former study site consists of a large (7,600 km2), circumboreal peatland that developed an extensive blanket of peat over the last 5000 years on a relatively flat glacial lake bed within a sub-humid to semi-arid climate gradient characterized by small annual atmospheric moisture surpluses and frequent droughts. The latter study site consists of a 0.92 km2 complex of small (meter-scale) "prairie pothole" wetlands located on a

Obituary: Allan R. Sandage (1926-2010)

Science.gov (United States)

Devorkin, David

2011-12-01

Weart on 22 May 1978, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD, USA, www.aip.org/history/ohilist/ and http://www.aip.org/history/ohilist/4380_1.html] Allan enrolled in Miami University in 1943 because his father was on the faculty there at the time. He majored in physics until he entered the Navy for 18 months to train as an electronics technician's mate. His training began in Chicago, where he became acquainted with others interested in astronomy, like Arthur Code and Albert Wilson, and then his tour took him to Gulfport, Mississippi, and finally to Treasure Island in the San Francisco Bay. When Sandage was discharged from the Navy his father was moving to the University of Illinois, so Allan transferred there, entering a much larger and more competitive physics department. He majored in physics and mathematics but he also minored in philosophy, and took a celestial mechanics course from Robert H. Baker. He volunteered to work at the observatory, learning the art and craft of calibrating photographic plates so that magnitudes could be transferred and intercompared from plate to plate, an experience that he later realized prepared him well for his life career and also introduced him into Bart Bok's "star counting" circuit based at Harvard. In consequence, when Bok visited Illinois sometime in 1947, he invited Sandage to work at Harvard in their summer school at the Agassiz Station mapping Milky Way fields. Sandage applied both to Harvard and Caltech for graduate school. Harvard was very well established in its graduate program whereas Caltech was just beginning to offer the Ph.D. in astronomy. He chose Caltech because that was where the big telescopes were. His family had visited Mount Wilson in 1941 during a summer when his father was teaching at Berkeley, and since that time Sandage had dreamed of observing with those giant telescopes. Thus in September 1948, Sandage joined the first class of students to engage in formal graduate