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• 1. [Article] Examining ectomycorrhizal communities of ponderosa pine and lodgepole pine in the south-central Oregon pumice zone

  Background information is presented that provides historical perspectives on the field of mycology in the Pacific Northwest and its role in forest management. The series of events and decisions that have ...

  Citation × Citation Citation Abstract Copy Title: Examining ectomycorrhizal communities of ponderosa pine and lodgepole pine in the south-central Oregon pumice zone Author: Garcia, Maria Osuna Background information is presented that provides historical perspectives on the field of mycology in the Pacific Northwest and its role in forest management. The series of events and decisions that have led to previous studies (or lack of studies) in the field also dictate the directions of current research. Culture, philosophy, and history all play a role in the questions that may be asked today. Examining the past gives light to the questions that are asked in the present and future. Forest ecosystems of the Pacific Northwest are changing as a result of climate change. Rise of global temperatures, decline of winter precipitation, earlier loss of snowpack, and increased summer drought are altering the range of Pinus contorta. As environmental conditions change, Pinus ponderosa may establish within the historic Pinus contorta range. Successful pine species migration will be constrained by the distribution or co-migration of ectomycorrhizal fungi (EMF). Knowledge of the linkages among soil fungal diversity, community structure, and environmental factors is critical to understanding the organization and stability of pine ecosystems. The objectives of this study are to establish an informational foundation of the EMF communities of P. ponderosa and P. contorta in the Deschutes National Forest and to examine soil characteristics associated with community composition. We examined EMF root tips of P. ponderosa and P. contorta in soil cores and conducted soil chemistry analysis for P. ponderosa. Results indicate that Cenococcum geophilum, Rhizopogon salebrosus, and Inocybe flocculosa are dominant in both P. contorta and P. ponderosa soil cores. Rhizopogon spp. were ubiquitous in P. ponderosa. There was no significant difference between EMF communities of P. ponderosa and P. contorta at the species level. Ordination analysis suggests that pH, Bray-phosphorus, total phosphorus (P), carbon (C), mineralizable nitrogen (N), ammonium (NH₄) and nitrate (NO₃) are driving EMF community composition in P. ponderosa. We found a significant linear relationship between EMF species richness and mineralizable N. Title: Examining ectomycorrhizal communities of ponderosa pine and lodgepole pine in the south-central Oregon pumice zone Author: Garcia, Maria Osuna Background information is presented that provides historical perspectives on the field of mycology in the Pacific Northwest and its role in forest management. The series of events and decisions that have led to previous studies (or lack of studies) in the field also dictate the directions of current research. Culture, philosophy, and history all play a role in the questions that may be asked today. Examining the past gives light to the questions that are asked in the present and future. Forest ecosystems of the Pacific Northwest are changing as a result of climate change. Rise of global temperatures, decline of winter precipitation, earlier loss of snowpack, and increased summer drought are altering the range of Pinus contorta. As environmental conditions change, Pinus ponderosa may establish within the historic Pinus contorta range. Successful pine species migration will be constrained by the distribution or co-migration of ectomycorrhizal fungi (EMF). Knowledge of the linkages among soil fungal diversity, community structure, and environmental factors is critical to understanding the organization and stability of pine ecosystems. The objectives of this study are to establish an informational foundation of the EMF communities of P. ponderosa and P. contorta in the Deschutes National Forest and to examine soil characteristics associated with community composition. We examined EMF root tips of P. ponderosa and P. contorta in soil cores and conducted soil chemistry analysis for P. ponderosa. Results indicate that Cenococcum geophilum, Rhizopogon salebrosus, and Inocybe flocculosa are dominant in both P. contorta and P. ponderosa soil cores. Rhizopogon spp. were ubiquitous in P. ponderosa. There was no significant difference between EMF communities of P. ponderosa and P. contorta at the species level. Ordination analysis suggests that pH, Bray-phosphorus, total phosphorus (P), carbon (C), mineralizable nitrogen (N), ammonium (NH₄) and nitrate (NO₃) are driving EMF community composition in P. ponderosa. We found a significant linear relationship between EMF species richness and mineralizable N. Close

• 2. [Article] Variability in mesoscale circulation and its effects on zooplankton distribution in the Northern California Current

  In eastern boundary current upwelling ecosystems, mesoscale circulation features such as eddies and upwelling filaments play a prominent role in the transfer of water and the associated plankton from the ...

  Citation × Citation Citation Abstract Copy Title: Variability in mesoscale circulation and its effects on zooplankton distribution in the Northern California Current Author: Keister, Julie Eileen In eastern boundary current upwelling ecosystems, mesoscale circulation features such as eddies and upwelling filaments play a prominent role in the transfer of water and the associated plankton from the productive nearshore to the oligotrophic deep sea. The relationship between mesoscale circulation, zooplankton distributions, and the across-shelf transport of coastal taxa and biomass in the California Current System was studied using data collected as part of the U.S. Global Ocean Ecosystems Dynamics (GLOBEC) Northeast Pacific Program. Sea surface height from >13 years of satellite altimeter data was used to characterize the spatial and temporal variability in mesoscale circulation in the northern California Current (35°N-49°N) and explore mechanisms of variability. High spatial and temporal variation in mesoscale energy occurred. Energy was not strongly linked to upwelling winds, but did correspond to climate indices, indicating that basin-scale processes play a role in controlling the circulation. CTD casts, zooplankton net tows, and Acoustic Doppler Current Profiler (ADCP) velocities collected during a research cruise conducted in summer 2000 off Oregon and northern California were used to describe the effects of mesoscale circulation on distributions of zooplankton. During the cruise, a filament of the coastal upwelling jet extended seaward of Cape Blanco (42.8°N) resulting in the displacement of coastal zooplankton to >100 km off the continental shelf. Velocities and standing stocks of zooplankton were used to estimate seaward transport of 0.5 Sv in the upper 100 m of the filament, in which zooplankton biomass averaged ~20 mg carbon/m³. That offshore transport equated to >900 metric tons of carbon each day, and 4-5x10⁴ tons over the 6-8 week lifetime of the circulation feature. Although the flux represented a small portion (<2%) of the shelf zooplankton biomass, the transport resulted in an offshore "hot-spot" in which biomass was 3-4X higher than in the surrounding ocean. Distributions of early life history stages of euphausiids indicated that retention of coastal populations may be strongly affected by the offshore advection. Finally, satellite sea surface temperature (SST) and sampling conducted during five summers were used to explore variability in the relationship between mesoscale circulation features and distributions of zooplankton. Circulation patterns differed among cruises and were reflected in zooplankton distributions. Circulation features resulted in the occurrence of cold surface water and coastal taxa offshore, but species abundances and presence/absence of taxa at specific locations were not predictable from satellite SSTs. These results are relevant to studies of ecosystem dynamics and the global carbon cycle because mesoscale circulation plays an important role in the seaward transport of carbon, retention and loss of taxa from the continental shelf, and creation of offshore structure which may be exploited by upper trophic level organisms. Title: Variability in mesoscale circulation and its effects on zooplankton distribution in the Northern California Current Author: Keister, Julie Eileen In eastern boundary current upwelling ecosystems, mesoscale circulation features such as eddies and upwelling filaments play a prominent role in the transfer of water and the associated plankton from the productive nearshore to the oligotrophic deep sea. The relationship between mesoscale circulation, zooplankton distributions, and the across-shelf transport of coastal taxa and biomass in the California Current System was studied using data collected as part of the U.S. Global Ocean Ecosystems Dynamics (GLOBEC) Northeast Pacific Program. Sea surface height from >13 years of satellite altimeter data was used to characterize the spatial and temporal variability in mesoscale circulation in the northern California Current (35°N-49°N) and explore mechanisms of variability. High spatial and temporal variation in mesoscale energy occurred. Energy was not strongly linked to upwelling winds, but did correspond to climate indices, indicating that basin-scale processes play a role in controlling the circulation. CTD casts, zooplankton net tows, and Acoustic Doppler Current Profiler (ADCP) velocities collected during a research cruise conducted in summer 2000 off Oregon and northern California were used to describe the effects of mesoscale circulation on distributions of zooplankton. During the cruise, a filament of the coastal upwelling jet extended seaward of Cape Blanco (42.8°N) resulting in the displacement of coastal zooplankton to >100 km off the continental shelf. Velocities and standing stocks of zooplankton were used to estimate seaward transport of 0.5 Sv in the upper 100 m of the filament, in which zooplankton biomass averaged ~20 mg carbon/m³. That offshore transport equated to >900 metric tons of carbon each day, and 4-5x10⁴ tons over the 6-8 week lifetime of the circulation feature. Although the flux represented a small portion (<2%) of the shelf zooplankton biomass, the transport resulted in an offshore "hot-spot" in which biomass was 3-4X higher than in the surrounding ocean. Distributions of early life history stages of euphausiids indicated that retention of coastal populations may be strongly affected by the offshore advection. Finally, satellite sea surface temperature (SST) and sampling conducted during five summers were used to explore variability in the relationship between mesoscale circulation features and distributions of zooplankton. Circulation patterns differed among cruises and were reflected in zooplankton distributions. Circulation features resulted in the occurrence of cold surface water and coastal taxa offshore, but species abundances and presence/absence of taxa at specific locations were not predictable from satellite SSTs. These results are relevant to studies of ecosystem dynamics and the global carbon cycle because mesoscale circulation plays an important role in the seaward transport of carbon, retention and loss of taxa from the continental shelf, and creation of offshore structure which may be exploited by upper trophic level organisms. Close