Physical Sciences and Mathematics Commons^™

Moderate Increase In Tco2 Enhances Photosynthesis Of Seagrass Zostera Japonica, But Not Zostera Marina: Implications For Acidification Mitigation, Cale A. Miller, Brooke Love, Sylvia Yang

Environmental Sciences Faculty and Staff Publications

Photosynthesis and respiration are vital biological processes that shape the diurnal variability of carbonate chemistry in nearshore waters, presumably ameliorating (daytime) or exacerbating (nighttime) short-term acidification events, which are expected to increase in severity with ocean acidification (OA). Biogenic habitats such as seagrass beds have the capacity to reduce CO₂ concentration and potentially provide refugia from OA. Further, some seagrasses have been shown to increase their photosynthetic rate in response to enriched total CO₂ (TCO₂). Therefore, the ability of seagrass to mitigate OA may increase as concentrations of TCO₂ increase. In this study, we exposed …

Technical Note: A Minimally-Invasive Experimental System For Pco2 Manipulation In Plankton Cultures Using Passive Gas Exchange (Atmospheric Carbon Control Simulator), Brooke Love, M. Brady (Michael Brady) Olson, Tristen Wuori

Environmental Sciences Faculty and Staff Publications

As research into the biotic effects of ocean acidification has increased, the methods for simulating these environmental changes in the laboratory have multiplied. Here we describe the atmospheric carbon control simulator (ACCS) for the maintenance of plankton under controlled pCO2 conditions, designed for species sensitive to the physical disturbance introduced by the bubbling of cultures and for studies involving trophic interaction. The system consists of gas mixing and equilibration components coupled with large volume atmospheric simulation chambers. These chambers allow gas exchange to counteract the changes in carbonate chemistry induced by the metabolic activity of the organisms. The system is …

Nutrient And Phytoplankton Dynamics On The Inner Shelf Of The Eastern Bering Sea, Calvin W. Mordy, Allan H. (Allan Houston) Devol, Lisa B. Eisner, Nancy Kachel, Carol A. Ladd, Michael W. Lomas, Peter Proctor, Raymond Nicholas Sambrotto, David Shull, Phyllis Jean Stabeno, Eric Wisegarver

Environmental Sciences Faculty and Staff Publications

In the Bering Sea, the nitrogen cycle near Nunivak Island is complicated due to limited nutrient replenishment across this broad shelf, and substantial nitrogen loss through sedimentary processes. While diffusion at the inner front may periodically support new production, the inner shelf in this region is generally described as a regenerative system. This study combines hydrographic surveys with measurements of nitrogen assimilation and benthic fluxes to examine nitrogen cycling on the inner shelf, and connectivity between the middle and inner shelves of the southern and central Bering Sea. Results establish the inner shelf as primarily a regenerative system even in …

Rapid Variations In Fluid Chemistry Constrain Hydrothermal Phase Separation At The Main Endeavour Field, Brooke Love, Marvin Douglas Lilley, David Allen Butterfield, Eric J. Olson, Benjamin Isaac Larson

Environmental Sciences Faculty and Staff Publications

Previous work at the Main Endeavour Field (MEF) has shown that chloride concentration in high-temperature vent fluids has not exceeded 510 mmol/kg (94% of seawater), which is consistent with brine condensation and loss at depth, followed by upward flow of a vapor phase toward the seafloor. Magmatic and seismic events have been shown to affect fluid temperature and composition and these effects help narrow the possibilities for sub-surface processes. However, chloride-temperature data alone are insufficient to determine details of phase separation in the upflow zone. Here we use variation in chloride and gas content in a set of fluid samples …

Cluster Analysis And Topoclimate Modeling To Examine Bristlecone Pine Tree-Ring Growth Signals In The Great Basin, Usa, Tyler J. Tran, Jamis M. Bruening, Andrew Godard Bunn, Matthew W. Salzer, Stuart B. Weiss

Environmental Sciences Faculty and Staff Publications

Tree rings have long been used to make inferences about the environmental factors that influence tree growth. Great Basin bristlecone pine is a long-lived species and valuable dendroclimatic resource, but often with mixed growth signals; in many cases, not all trees at one location are limited by the same environmental variable. Past work has identified an elevational threshold below the upper treeline above which trees are limited by temperature, and below which trees tend to be moisture limited. This study identifies a similar threshold in terms of temperature instead of elevation through fine-scale topoclimatic modeling, which uses a suite of …

Fine-Scale Modeling Of Bristlecone Pine Treeline Position In The Great Basin, Usa, Jamis M. Bruening, Tyler J. Tran, Andrew Godard Bunn, Stuart B. Weill, Matthew W. Salzer

Environmental Sciences Faculty and Staff Publications

Great Basin bristlecone pine (Pinus longaeva) and foxtail pine (Pinus balfouriana) are valuable paleoclimate resources due to their longevity and climatic sensitivity of their annually-resolved rings. Treeline research has shown that growing season temperatures limit tree growth at and just below the upper treeline. In the Great Basin, the presence of precisely dated remnant wood above modern treeline shows that the treeline ecotone shifts at centennial timescales tracking long-term changes in climate; in some areas during the Holocene climatic optimum treeline was 100 meters higher than at present. Regional treeline position models built exclusively from climate …

Predicting Landscape Effects Of Mississippi River Diversions On Soil Organic Carbon Sequestration, Hongqing Wang, Gregory D. Steyer, Brady R. (Brady Randall) Couvillion, Holly Beck, John M. Rybczyk, Victor H. Rivera-Monroy, Ken W. Krauss, Jenneke M. (Jenneke Maria) Visser

Environmental Sciences Faculty and Staff Publications

Large Mississippi River (MR) diversions (peak water flow >1416 m³/s and sediment loads >165 kg/s) have been proposed as part of a suite of coastal restoration projects and are expected to rehabilitate and rebuild wetlands to alleviate the significant historic wetland loss in coastal Louisiana. These coastal wetlands are undergoing increasing eustatic sea-level rise, land subsidence, climate change, and anthropogenic disturbances. However, the effect of MR diversions on wetland soil organic carbon (SOC)

sequestration in receiving basins remains unknown. The rate of SOC sequestration or carbon burial in wetlands is one of the variables used to assess the …

Western Spruce Budworm And Wildfire: Is There A Connection?, Daniel G. Gavin, Aquila Flower, Greg M. Cohn, Russell A. Parsons, Emily K. Heyerdahl

Environmental Sciences Faculty and Staff Publications

In the interior Pacific Northwest, extensive defoliation of mixed conifer forests during outbreaks of western spruce budworm (WSB) may leave the visual impression of a tinderbox with trees primed to burst into flame. But is this the case?

We addressed this question with funding from the USDA/U.S. Department of the Interior Joint Fire Science Program (project 09– 1–06–5). Here we summarize our three recent publications exploring the potential relationship between WSB outbreaks and fire. We used a multimethod approach to explore potential disturbance interactions that might cause one disturbance to change the occurrence or severity of the other. We used …