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2. Diversity among rare and common congeneric plant species from the Garry oak and Okanagan shrub-steppe ecosystems in British Columbia: implications for conservation.
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Hersh, Evan W., Wheeler, Erica J., Costanzo, Brenda, Ramakrishnan, Alisa P., Miscampbell, Allyson E., Ritland, Carol, Whitton, Jeannette, Gorrell, Jamieson C., and Harrower, William
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PLANT species ,COLONIZATION (Ecology) ,ENDANGERED species ,NON-coding DNA ,SHRUBS ,PLANT diversity ,ECOSYSTEMS ,CHLOROPLAST DNA - Abstract
It is often assumed that the northern peripheral populations of species' ranges are genetically depauperate due in part to founder effects from postglacial colonization. The majority of federally protected plant species are peripheral in Canada, yet we have little information about their patterns of genetic diversity and structure. In British Columbia, the majority of these protected plant species occur in two threatened habitats: the Garry oak and Okanagan shrub-steppe ecosystems. Using universal noncoding chloroplast DNA markers, we investigated genetic diversity and genetic structure in four rare and common plant species pairs inhabiting these two ecosystems. We found that rare species had lower genetic diversity than their common congeners, and detected contrasting patterns of regional diversity and structure based on ecosystem. Species from the Garry oak ecosystem showed lower genetic diversity in the northern deglaciated region and significant differentiation between regions, likely due to limited dispersal between Vancouver Island and the mainland. Species from the Okanagan shrub-steppe, however, tended to have uniform diversity across their range and lack regional structure. This study provides an important first look at the phylogeographic patterns of four rare plant species in British Columbia. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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3. Bridge infrastructure resilience assessment against seismic hazard using Bayesian best worst method.
- Author
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Khan, Md Saiful Arif, Etonyeaku, Leonard Chinedu, Kabir, Golam, Billah, Muntasir, and Dutta, Subhrajit
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EARTHQUAKE hazard analysis ,HAZARD mitigation ,NATURAL disasters ,JUDGMENT (Psychology) ,TRANSPORTATION agencies - Abstract
Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
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4. Late Pleistocene heather vole, Phenacomys, on the North Pacific Coast of North America: environments, local extinctions, and archaeological implications.
- Author
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Steffen, Martina L.
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PLEISTOCENE-Holocene boundary ,VOLES ,FRAGMENTED landscapes ,PLEISTOCENE Epoch ,PRESERVATION of antiquities - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
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5. Globally significant Early Permian crinoids from the Mount Mark Formation in Strathcona Provincial Park, Vancouver Island, British Columbia — preliminary analysis of a disappearing fauna.
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Webster, G. D., Haggart, James W., Saxifrage, Carrie, Saxifrage, Barry, Gronau, Christian, and Douglas, Aileen
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DISPARIDA ,CLADIDA ,WEATHERING ,PALEOZOIC stratigraphic geology - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2009
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6. Late Quaternary paleoproductivity history on the Vancouver Island margin, western Canada: a multiproxy geochemical study.
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Chang, Alice S., Pedersen, Thomas F., and Hendy, Ingrid L.
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ANALYTICAL geochemistry ,PLEISTOCENE stratigraphic geology ,SEDIMENTATION & deposition ,PORE fluids ,HYDROGRAPHY - Abstract
Multiproxy analysis of a 38 m long sediment core recovered from the Vancouver Island margin (48.97°N, 127.04°W, water depth 1243 m) has yielded a millennial-scale history of upwelling and export production over the last ~50 ka. Higher concentrations of marine organic carbon, opal, and trace Mo suggest that production was higher, and sedimentary pore waters more anoxic, during the warm Holocene, Bølling–Allerød, and interstadial events between 31 and 44 ka BP. Relatively lower production and higher inputs of terrigenous organic matter occurred during the last glacial (14.7–31 ka BP; Cordilleran ice sheet proximal to coring site at ~19.5 ka BP) and from 44–50.4 ka BP. Enrichments in sedimentary δ
15 N during interstadial events are interpreted to reflect episodic delivery and upwelling of isotopically heavy nitrate to the surface waters and subsequent vectoring to the seafloor via settling planktonic detritus. Similar patterns are seen in southern California and other areas along the western margin of North America, implying that heavier nitrate generated by denitrification in the Eastern Tropical North Pacific has in the past been carried northward in the California Undercurrent at least as far as central Vancouver Island. This inference is consistent with modern hydrographic observations in the region. Comparison of the coherent Vancouver Island, Oregon, California, and northwest Mexico margin records with late Pleistocene climate history in Greenland reinforces the conclusion that a tight physical and biogeochemical coupling has existed for at least 50 ka between the North Atlantic and North American margin waters, including those off Vancouver Island. Une analyse de multiples indicateurs substituts dans une carotte de sédiments de 38 m prélevée à la limite de l’île de Vancouver (48,97°N, 127,04°O, profondeur d’eau de 1243 m) a donné un historique d’échelle millénaire de remontée d’eau et de production au cours des derniers 50 milliers d’années. Des concentrations plus élevées de carbone organique marin, d’opale et de traces de Mo suggèrent une la production plus élevée et des eaux de pores sédimentaires plus anoxiques au cours de l’Holocène chaud, du Bølling–Allerød et des événements interstadiaires il y a entre 31 et 44 milliers d’années avant le présent (ka BP). Il y avait relativement moins de production et plus d’intrants de matière organique terrigène durant la dernière période glaciaire (14,7–31 ka BP; l’Inlandsis de la Cordillère était présent à proximité du site de carottage vers 19,5 ka BP) et de 44–50,4 ka BP. Des enrichissements en δ15 N durant les événements interstadiaires sont interprétés comme le reflet de livraisons épisodiques et de la remontée de nitrate isotopiquement lourd vers les eaux de surface puis d’un cheminement vers le fond de l’océan avec les détritus de plancton. Des patrons similaires peuvent être constatés dans le sud de la Californie et à d’autres endroits le long de la bordure ouest de l’Amérique du Nord, impliquant que le nitrate plus lourd, généré par de la dénitrification dans l’Est tropical du Pacifique Nord, a jadis été porté vers le nord par le sous-courant de la Californie et s’est rendu au moins aussi loin que le centre de l’île de Vancouver. Cette inférence concorde avec les observations hydrographiques modernes dans la région. Une comparaison des données de bordure de l’île de Vancouver, de l’Oregon, de la Californie et du nord-ouest du Mexique, cohérentes avec l’historique climatique au Pléistocène tardif au Groenland, appuie la conclusion que, pour au moins 50 ka, il existait un jumelage physique et biogéochimique serré entre les eaux de bordure de l’Amérique du Nord et de l’Atlantique Nord, incluant les eaux au large de l’île de Vancouver. [ABSTRACT FROM AUTHOR]- Published
- 2008
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7. Contrasting effects of coastal upwelling on growth and recruitment of nearshore Pacific rockfishes (genus Sebastes).
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Markel, Russell W. and Shurin, Jonathan B.
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CONTRAST effect ,OCEAN temperature ,POPULATION dynamics ,STRIPED bass ,OCEAN dynamics ,CHLOROPHYLL in water - Abstract
Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
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8. Multiple-pathway succession in coastal Tsuga heterophylla, Thuja plicata, and Abies amabilis forests on northeastern Vancouver Island, British Columbia.
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Weber, Adrian, Kimmins, J. P. (Hamish), Gilbert, Benjamin, Yueh-Hsin Lo, and Blanco, Juan A.
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WESTERN hemlock ,WESTERN redcedar ,ABIES amabilis ,FORESTS & forestry ,SUSTAINABLE forestry ,FOREST ecology ,PLANT species - Abstract
Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2014
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9. Bus networks as graphs: new connectivity indicators with operational characteristics.
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Quintero-Cano, Liliana, Wahba, Mohamed, and Sayed, Tarek
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URBAN planning ,METROPOLITAN area network industry ,BUS lines ,BUS transportation ,TRAFFIC flow measurement ,SOCIAL history ,TWENTY-first century - Abstract
Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2014
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10. Cascadiacarpa exilis sp. nov.: new fruits of Fagaceae from the Eocene of British Columbia.
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Mindell, Randal A., Stockey, Ruth A., and Beard, Graham
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FRUIT research ,FAGACEAE ,EOCENE Epoch ,CELLULOSE acetate ,FOSSIL plants - Abstract
Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2014
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11. Multifractal patterns in the daily catch time series of smooth pink shrimp ( Pandalus jordani) from the west coast of Vancouver Island, Canada.
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Montes, Rodrigo M., Perry, R. Ian, Pakhomov, Evgeny A., Edwards, Andrew M., Boutillier, James A., and Sainte-Marie, Bernard
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PANDALUS jordani fisheries ,FISH population viability analysis ,MATHEMATICAL models of fish populations ,MULTIFRACTALS ,TIME series analysis ,SCALING laws (Statistical physics) ,FISHERY management - Abstract
Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
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12. The temporal development of old-growth structural attributes in second-growth stands: a chronosequence study in the Coastal Western Hemlock zone in British Columbia.
- Author
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Gerzon, Michael, Seely, Brad, and MacKinnon, Andy
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COASTAL forests ,FOREST management ,COARSE woody debris ,STANDARD deviations - Abstract
Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
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13. Great earthquakes on Canada’s west coast: a review.
- Author
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Hyndman, Roy D. and Rogers, Garry C.
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TRANSECT method ,EARTHQUAKES ,TSUNAMIS ,CASCADIA subduction zone - Abstract
The first Lithoprobe transect in 1984 across Vancouver Island had primary objectives to define the structure associated with subduction and constraints on the potential for great thrust earthquakes. The Lithoprobe results and the comprehensive multidisciplinary data collection and analyses that followed provide compelling evidence for past great earthquakes along the Cascadia subduction zone from Vancouver Island to northernmost California, and for present elastic strain build up toward future great events. There is evidence of sudden coastal subsidence up to 2 m and of deep-sea turbidite deposits indicating strong shaking from huge earthquakes at irregular intervals averaging about 500 years, the last in 1700. Precision geodetic measurements define the present buckling of the coastal region, diagnostic of elastic strain accumulation on a locked thrust fault. The landward extent of rupture and, therefore, shaking at coastal cities is constrained by (i) the pattern of elastic strain buildup, (ii) the estimated temperatures on the fault, (iii) the updip limit of episodic tremor and slip (ETS), (iv) the downdip change in reflection character of the thrust, and (v) the magnitude of coastal subsidence in the most recent, 1700, and previous great events. The major earthquakes are very large, M9, rupturing most of the Cascadia margin, but mainly offshore, limiting somewhat the shaking at inland cities but producing large tsunamis. The ETS that occurs at intervals of just over a year appears to involve slow slip on the subduction thrust downdip of the rupture zone that increases stress on the locked zone and may indicate time varying potential for great events. Les principaux objectifs du premier transect Lithoprobe traversant l’île de Vancouver en 1984 étaient de définir la structure associée à la subduction et les contraintes sur le potentiel de grands tremblements de terre par chevauchement. Les résultats Lithoprobe, et la collecte et l’analyse des très vastes données multidisciplinaires qui en ont découlé, fournissent des évidences convaincantes pour d’anciens grands tremblements de terre le long de la zone de subduction Cascadia, de l’île de Vancouver à l’extrémité nord de la Californie, et pour l’actuelle contrainte de déformation élastique qui s’accumule pour causer de futurs grands événements. Il existe des preuves d’une soudaine subsidence de la côte atteignant 2 m et la déposition de dépôts de turbidites dans les grands fonds océaniques, ce qui indique de fortes secousses de grands tremblements de terre à des intervalles irréguliers, d’une moyenne d’environ 500 ans, le dernier ayant eu lieu en 1700. Des mesures géodésiques précises définissent le flambage actuels de la région de la côte, diagnostiquant une accumulation de contraintes de déformation élastique sur une faille chevauchante figée. L’étendue de rupture vers le continent, et donc le tremblement aux villes côtières, est limitée par (i) les tendances d’accumulations de contraintes de déformation élastique, (ii) la température estimée de la faille, (iii) la limite en amont-pendage de trémors et de glissements épisodiques (TGÉ), (iv) le changement en aval-pendage du caractère de réflexion du chevauchement et (v) la magnitude de la subsidence côtière lors des grands évé nements les plus récent, ceux de 1700 et les anciens. La plupart des principaux tremblements de terre sont très gros, M9, brisant la plus grande partie de la bordure Cascadia surtout; cependant, au large, limitant quelque peu le tremblement aux villes internes mais produisant de grands tsunamis. Les TGÉqui se produisent à des intervalles légèrement supérieurs à un an semblent impliquer un glissement lent sur le chevauchement de la subduction en aval-pendage de la zone de rupture, ce qui augmente progressivement les contraintes sur la zone figée; ils pourraient aussi indiquer un potentiel, variable dans le temps, pour de grands événements. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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14. Postglacial evolution of a Pacific coastal fjord in British Columbia, Canada: interactions of sea-level change, crustal response, and environmental fluctuations — results from MONA core MD02-2494.
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Dallimore, Audrey, Enkin, Randolph J., Pienitz, Reinhard, Southon, John R., Baker, Judith, Wright, Cynthia A., Pedersen, Tom F., Calvert, Steve E., Ivanochko, Tara, and Thomson, Richard E.
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HOLOCENE paleoceanography ,FJORD ecology ,SEDIMENTATION & deposition ,ABSOLUTE sea level change ,DIATOMS ,PALEOMAGNETISM ,PLEISTOCENE-Holocene boundary - Abstract
The sedimentary record in a 40.9 m giant (Calypso) piston core (MD02-2494) raised from the inner basin within Effingham Inlet, British Columbia, Canada, during the 2002 Marges Ouest Nord Américaines (MONA) campaign, spans from 14 360
14 C years BP (17 300 calibrated calendar (cal.) years BP) to about nine centuries before present. The core archives changes in sedimentation and sea level immediately following deglaciation of the Late Wisconsin Fraser Glaciation, which peaked about 15 00014 C years BP. The presence of the Mazama Ash in the core anchors a detailed chronology based on 49 radiocarbon dates and seven Pleistocene paleomagnetic secular variation correlations. Diatom assemblages identify a marine–freshwater–marine transition in the basin, which occurred 11 63014 C years BP (13 500 cal. years BP). At this time, a bedrock sill, presently at 46 m depth, was briefly exposed as sea level fell and then rose again during isostatic crustal adjustments. These data constrain a new sea-level curve for the outer coast of Vancouver Island covering the past 12 00014 C years BP (14 000 cal. years BP), providing new information on the nature of deglaciation along the west coast of Canada and informing interpretations of regional paleoceanographic records and mantle viscosity models. Les données sédimentaires enregistrées dans une carotte (MD02-2494) de 40,9 m prélevée par un carottier géant à piston (Calypso) dans le bassin interne du passage Effingham, Colombie-Britannique, Canada, au cours de la campagne MONA (Marges Ouest Nord-Américaines) couvrent une période allant de 14 360 années14 C avant le présent (17 300 années calendaires avant le présent – années cal. BP) à environ neuf siècles avant le présent. La carotte enregistre les changements dans la sédimentation et les niveaux de la mer immédiatement après la déglaciation de la glaciation de la fin du Wisconsinien (Fraser) dont la crête a eu lieu vers 15 000 années14 C BP. La présence de cendre volcanique Mazama dans la carotte confirme une chronologie détaillée basée sur 49 datations au radiocarbone et 7 corrélations paléomagnétiques de variations séculaires datant du Pléistocène. Les assemblages de diatomées identifient une transition marine-eau douce-marine dans le bassin à 11 630 années14 C BP (13 500 années cal. BP). À cette époque, un filon couche du socle, maintenant à une profondeur de 46 m, a été brièvement exposé alors que le niveau de la mer a chuté et ensuite remonté durant les ajustements isostatiques de la croûte. Ces données imposent des limites à une nouvelle courbe de niveau de la mer pour la côte Ouest de l’île de Vancouver pour les dernières 12 00014 C années avant le présent (14 000 années cal. BP); elles fournissent de nouvelles informations quant à la nature de la déglaciation le long de la côte Ouest du Canada et contribuent à orienter les interprétations des données paléocéaniques régionales et les modèles de viscosité du manteau. [ABSTRACT FROM AUTHOR]- Published
- 2008
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15. Determining the post-glacial evolution of a northeast Pacific coastal fjord using a multiproxy geochemical approach.
- Author
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Ivanochko, Tara S., Calvert, Stephen E., Southon, John R., Enkin, Randolph J., Baker, Judith, Dallimore, Audrey, and Pedersen, Thomas F.
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HOLOCENE stratigraphic geology ,ANALYTICAL geochemistry ,OCEAN circulation ,FJORD ecology ,OPALS ,SEDIMENTS ,ANOXIC zones - Abstract
A 40.32 m piston core recovered from Effingham Inlet, on the west coast of Vancouver Island, provides the basis for a high-resolution geochemical study of the last deglaciation and the Holocene. Glacial retreat, basin isolation, sea-level rise, and productivity variations are determined using proxies for sediment composition (K/Al, Fe/Al, Mg/Al), grain size (Ti/Al, Zr/Al), sedimentary redox conditions (Mo/Al, U/Al), and productivity (wt.% organic carbon, wt.% opal). As local ice retreated and marine waters inundated the basin, coarse-grained glacimarine sediments were replaced by finer grained, laminated, opal-rich sediments. During meltwater pulse-1a, the dominance of local crustal rise over eustatic sea-level rise resulted in the progressive restriction of ocean circulation in Effingham Inlet and the formation of a temporary freshwater lake. The transition into stable Holocene conditions was initiated at ~12 700 BP, which corresponds to the onset of the Younger Dryas, as identified by the Greenland Ice core Project (GRIP) ice core δ
18 O record and was completed by 10 700 BP, ~800 years after the GRIP ice core record stabilized. Holocene Mo/Al and U/Al ratios range between 12–35 (×104 ) and 1–3.4 (×104 ), respectively, indicating that although large-amplitude, high-frequency fluctuations occur, the sediments of Effingham Inlet inner basin have remained organic rich and oxygen depleted for the entire Holocene period. The combination of anoxic bottom waters and a Holocene sedimentation rate of 217 cm/ka have preserved a high-resolution record of environmental change in the northeast Pacific over the last 11 000 years. Une carotte de 40,32 m, prélevée au moyen d’un carottier à piston au passage Effingham, sur la Côte Ouest de Vancouver, fournit la base pour une étude géochimique très détaillée de la dernière déglaciation et de l’Holocène. Le retrait glaciaire, l’isolement du bassin, l’élévation du niveau de la mer et les variations de productivité sont déterminés en utilisant des substituts pour la composition des sédiments (K/Al, Fe/Al, Mg/Al), la granulométrie (Ti/Al, Zr/Al), les conditions d’oxydoréduction sédimentaires (Mo/Al, U/Al) et la productivité (% poids carbone organique, % poids opale). À mesure que la glace locale se retirait et que les eaux marines inondaient le bassin, des sédiments glaciomarins à grain grossier étaient remplacés par des sédiments laminés, à grain plus fin et riches en opale. Durant un épisode important de montée du niveau marin global (meltwater pulse 1A), la dominance de la montée locale de la croûte par rapport à la hausse eustatique du niveau de la mer a progressivement restreint la circulation de l’océan dans le passage Effingham et a conduit à la formation d’un lac temporaire d’eau douce. La transition vers les conditions stables à l’Holocène a débuté vers 12 700 BP, ce qui correspond au début du Dryas récent, tel qu’identifié par les enregistrements de δ18 O dans les carottes de glace du projet GRIP (« Greenland Ice Core Project ), et qui était terminé à 10 700 BP, soit environ 800 ans après la stabilization des enregistrements dans les carottes de glace du GRIP. À l’Holocène, les rapports Mo/Al et U/Al varient respectivement entre 12–35 (×104 ) et 1–3,4 (×104 ), indiquant que, malgré l’occurrence de fluctuations de grande amplitude et de fréquence élevée, les sédiments du bassin interne du passage Effingham sont demeurés riches en matières organiques et pauvres en oxygène pour toute la période de l’Holocène. La combinaison d’eaux de fond anoxiques et d’un taux de sédimentation de 217 cm/ka à l’Holocène a préservé l’enregistrement très détaillé du changement environnemental dans le Nord-Est du Pacifique au cours des derniers 11 000 ans. [ABSTRACT FROM AUTHOR]- Published
- 2008
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16. Geochemical reconstruction of Pacific decadal variability from the eastern North Pacific during the Holocene.
- Author
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Ivanochko, Tara S., Calvert, Stephen E., Thomson, Richard E., and Pedersen, Thomas F.
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HOLOCENE stratigraphic geology ,ANOXIC zones ,OCEANOGRAPHIC research ,FJORD ecology ,ACCELERATOR mass spectrometry - Abstract
Determining climate variations over the Holocene requires high-resolution records with well-developed age models. A 40 m long marine sediment core raised from Effingham Inlet, an anoxic fjord on the west coast of Vancouver Island, British Columbia, Canada, yields such a record. Forty six
14 C accelerator mass spectrometry (AMS) dates determined from terrestrial plant material form the age model. Downcore sampling at both 5 cm (20 year) and 1.5 cm (7 year) resolution indicates that high-frequency oceanographic variability has prevailed at this site over the last 10 000 years. Spectral analysis of wt.% opal, a proxy for diatom productivity in the basin, reveals the bidecadal and pentadecadal periods of the Pacific decadal oscillation (PDO) – North Pacific index (NPI) that are related to changes in the strength of the Aleutian Low. Coherence analysis between the Effingham Inlet data and δ18 O records from Jellybean Lake (a high elevation site in southwest Yukon) indicates regional coherence at periods of 45, 70, and 510 years between productivity in Effingham Inlet and changes in the Aleutian Low strength. Over the entire Holocene, the strength of decadal variability has changed. Both 20- and 50-year periods are present to some degree in the early Holocene, and only the 50 year period is evident in the late Holocene. These data imply that regime shifts would have been more frequent in the early Holocene relative to the last several thousand years. La détermination des variations climatiques au cours de l’Holocène demande des enregistrements à haute résolution et des modèles d’âge bien développés. Une carotte de sédiments marins d’une longueur de 40 m, prélevée dans le passage Effingham, un fjord anoxique sur la côte Ouest de l’île de Vancouver, au Canada, a fourni un tel enregistrement. Quarante-six dates14 C, obtenues par SMA (spectrométrie de masse avec accélérateur) à partir de matériel de plantes terrestres, forment le modèle d’âge. Des échantillons de la carotte à une résolution de 5 cm (20 ans) et de 1,5 cm (7 ans) indiquent que ce site était sujet à une variabilité océanographique de grande fréquence au cours des derniers 10 000 ans. Une analyse spectrale du pourcentage d’opale, un substitut à la productivité des diatomées dans le bassin, a révélé des périodes bi-décennales et penta-décennales de l’Oscillation décennale du Pacifique – l’indice du Pacifique Nord qui sont reliées aux changements de la dépression des Aléoutiennes. Une analyse de cohérence entre les données du passage Effingham et les enregistrements δ18 O du lac Jellybean (un site à haute élévation dans le sud-ouest du Yukon) indique une cohérence régionale à des périodes de 45, 70 et 510 ans entre la productivité dans le passage Effingham et les changements de force de la dépression des Aléoutiennes. Durant tout l’Holocène, l’amplitude de la variabilité décennale a changé. Les périodes de 20 et de 50 ans sont présentes à un certain degré à l’Holocène précoce alors que seule la période de 50 ans est évidente à l’Holocène tardif. Ces données impliquent que des changements de régime auraient été plus fréquents à l’Holocène précoce par rapport aux quelques derniers milliers d’années. [ABSTRACT FROM AUTHOR]- Published
- 2008
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17. Colonization and decomposition of salal (Gaultheria shallon) leaf litter by saprobic fungi in successional forests on coastal British Columbia.
- Author
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Osono, Takashi, Iwamoto, Susumu, and Trofymow, John A.
- Subjects
FUNGI ,LEAVES ,FOLIAR diagnosis ,BACTERIAL colonies ,BIODEGRADATION ,GAULTHERIA ,MARASMIUS - Abstract
The colonization of leaf litter by saprobic fungi was studied in old-growth and post-harvest successional Douglas-fir forests on southeast Vancouver Island, British Columbia. This study focused on leaf litter of salal (Gaultheria shallon Pursh.), a dominant understory shrub in all stands. Salal litter is characterized by the occurrence of bleached portions attributable to fungal colonization of the litter and to the variable decomposition of recalcitrant compounds, such as lignin. Analyses of proximate chemical fractions, fungal assemblages on the bleached leaf area, and pure culture decomposition assays indicated that Marasmius sp. and Coccomyces sp. were responsible for rapid decomposition and bleaching of salal leaf litter. The bleached area accounted for 17%-22% of total area of salal leaf litter collected in immature (40-60 years old), mature (85-105 years old), and old-growth (more than 290 years old) stands, but for only 2% in regeneration (5-15 years old) stands. The reduction of bleached leaf area occupied by Marasmius sp. and Coccomyces sp. in regeneration stands could be due to the changes in microenvironmental conditions on the forest floor, in litter quality, or in food-web structure in soils. The decrease of fungi able to decay recalcitrant compounds may lead to a reduction of salal decomposition rates in clear-cut sites that would persist until canopy closure occurs. La colonisation de la litière de feuilles par des champignons saprobiques a été étudiée dans des secteurs de forêt ancienne et des secteurs en régénération de forêts successionnelles de sapins Douglas, dans le sud-est de l’Ile de Vancouver, Colombie-Britannique. L’étude s’est concentrée sur la litière de feuilles de gaulthérie salai (Gaultheria shallon Pursh.), un arbuste dominant du sous-étage. La litière de gaulthérie se caractérise par la présence de zones décolorées attribuables à une colonisation fongique de la litière et à la décomposition variable de composés récalcitrants comme la lignine. Des analyses des fractions chimiques immédiates et des assemblages de champignons sur les parties décolorées des feuilles ainsi que des essais de décomposition de cultures pures ont indiqué que Marasmius sp. et Coccomyces sp. étaient responsables de la décomposition rapide et de la décoloration des feuilles de gaulthérie. Les régions décolorées constituaient de 17 % à 22 % de la surface totale de la litière de feuilles de gaulthérie récoltées dans les zones immatures (40 à 60 ans), matures (85 à 105 ans) et âgées (plus de 290 ans), mais seulement 2 % dans les zones en régénération (5 à 15 ans). La réduction des surfaces décolorées occupées par Marasmius sp. et Coccomyces sp. dans les zones en régénération pourrait être due à des changements des conditions micro-environnementales du plancher forestier, à la qualité de la litière ou à la structure de l’écosystème des sols. La diminution des champignons capables de dégrader des composés récalcitrants pourrait conduire à la réduction des taux de décomposition de gaulthérie dans les zones de coupes, qui pourrait persister jusqu’à ce que la canopée se referme. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
18. Multiple deformation episodes at Myra Falls volcanic-hosted massive sulfide camp, central Vancouver Island, British Columbia, Canada.
- Author
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Jones, Sarah, Berry, Ron, and Sinclair, Briony
- Subjects
ISLANDS ,DEFORMATIONS (Mechanics) ,MAGNETIC flux compression ,CLEAVAGE of rocks ,SHEAR (Mechanics) ,GEOLOGIC faults ,STRUCTURAL geology - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
19. Vocal individuality as a potential long-term monitoring tool for Western Screech-owls, Megascops kennicottii.
- Author
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Tripp, T. M. and Otter, K. A.
- Subjects
ORNITHOLOGY ,BIRDS ,SCREECH owls ,ANIMAL sound recording & reproducing ,BIRDSONGS ,ANIMAL sounds ,WILDLIFE monitoring - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
20. Cenozoic ichthyolith biostratigraphy: Tofino Basin, British Columbia.
- Author
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Johns, Marjorie J., Barnes, Christopher R., and Narayan, Y. Roshni
- Subjects
EARTH sciences ,CENOZOIC paleoseismology ,ICHTHYOLITHS ,SUTURE zones (Structural geology) ,STRUCTURAL geology ,EOCENE-Oligocene boundary ,MIOCENE stratigraphic geology - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
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