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Full-Text Articles in Physical Sciences and Mathematics
Photorespiration In Eelgrass (Zostera Marina L.): A Photoprotection Mechanism For Survival In A Co₂-Limited World, Billur Celebi-Ergin, Richard C. Zimmerman, Victoria J. Hill
Photorespiration In Eelgrass (Zostera Marina L.): A Photoprotection Mechanism For Survival In A Co₂-Limited World, Billur Celebi-Ergin, Richard C. Zimmerman, Victoria J. Hill
OES Faculty Publications
Photorespiration, commonly viewed as a loss in photosynthetic productivity of C3 plants, is expected to decline with increasing atmospheric CO2, even though photorespiration plays an important role in the oxidative stress responses. This study aimed to quantify the role of photorespiration and alternative photoprotection mechanisms in Zostera marina L. (eelgrass), a carbon-limited marine C3 plant, in response to ocean acidification. Plants were grown in controlled outdoor aquaria at different [CO2]aq ranging from ~55 (ambient) to ~2121 μM for 13 months and compared for differences in leaf photochemistry by simultaneous measurements of O2 flux and …
Skeletal Light-Scattering Accelerates Bleaching Response In Reef-Building Corals, Timothy D. Swain, Emily Dubois, Andrew Gomes, Valentina P. Stoyneva, Andrew J. Radosevich, Jillian Henss, Michelle E. Wagner, Justin Derbas, Hannah Grooms, Elizabeth M. Velazquez, Joshua Traub, Brian J. Kennedy, Arabela A. Grigorescu, Mark W. Westneat, Kevin Sanborn, Shoshana Levine, Mark Schick, George Parsons, Brendan C. Briggs, Jeremy D. Rogers, Vadim Backman, Luisa A. Marcelino
Skeletal Light-Scattering Accelerates Bleaching Response In Reef-Building Corals, Timothy D. Swain, Emily Dubois, Andrew Gomes, Valentina P. Stoyneva, Andrew J. Radosevich, Jillian Henss, Michelle E. Wagner, Justin Derbas, Hannah Grooms, Elizabeth M. Velazquez, Joshua Traub, Brian J. Kennedy, Arabela A. Grigorescu, Mark W. Westneat, Kevin Sanborn, Shoshana Levine, Mark Schick, George Parsons, Brendan C. Briggs, Jeremy D. Rogers, Vadim Backman, Luisa A. Marcelino
Timothy Swain
Background At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer …
Experimental Impacts Of Climate Warming And Ocean Carbonation On Eelgrass Zostera Marina, Richard C. Zimmerman, Victoria J. Hill, Malee Jinuntuya, Billur Celebi, David Ruble, Miranda Smith, Tiffany Cedeno, W. Mark Swingle
Experimental Impacts Of Climate Warming And Ocean Carbonation On Eelgrass Zostera Marina, Richard C. Zimmerman, Victoria J. Hill, Malee Jinuntuya, Billur Celebi, David Ruble, Miranda Smith, Tiffany Cedeno, W. Mark Swingle
OES Faculty Publications
CO2 is a critical and potentially limiting substrate for photosynthesis of both terrestrial and aquatic ecosystems. In addition to being a climate-warming greenhouse gas, increasing concentrations of CO2 will dissolve in the oceans, eliciting both negative and positive responses among organisms in a process commonly known as ocean acidification. The dissolution of CO2 into ocean surface waters, however, also increases its availability for photosynthesis, to which the highly successful, and ecologically important, seagrasses respond positively. Thus, the process might be more accurately characterized as ocean carbonation. This experiment demonstrated that CO2 stimulation of primary production enhances …
Skeletal Light-Scattering Accelerates Bleaching Response In Reef-Building Corals, Timothy D. Swain, Emily Dubois, Andrew Gomes, Valentina P. Stoyneva, Andrew J. Radosevich, Jillian Henss, Michelle E. Wagner, Justin Derbas, Hannah Grooms, Elizabeth M. Velazquez, Joshua Traub, Brian J. Kennedy, Arabela A. Grigorescu, Mark W. Westneat, Kevin Sanborn, Shoshana Levine, Mark Schick, George Parsons, Brendan C. Briggs, Jeremy D. Rogers, Vadim Backman, Luisa A. Marcelino
Skeletal Light-Scattering Accelerates Bleaching Response In Reef-Building Corals, Timothy D. Swain, Emily Dubois, Andrew Gomes, Valentina P. Stoyneva, Andrew J. Radosevich, Jillian Henss, Michelle E. Wagner, Justin Derbas, Hannah Grooms, Elizabeth M. Velazquez, Joshua Traub, Brian J. Kennedy, Arabela A. Grigorescu, Mark W. Westneat, Kevin Sanborn, Shoshana Levine, Mark Schick, George Parsons, Brendan C. Briggs, Jeremy D. Rogers, Vadim Backman, Luisa A. Marcelino
Marine & Environmental Sciences Faculty Articles
Background At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer …
Effects Of Elevated Pco2 And Irradiance On Growth, Photosynthesis And Calcification In Halimeda Discoidea, K. E. Peach, M. S. Koch, Patricia Blackwelder
Effects Of Elevated Pco2 And Irradiance On Growth, Photosynthesis And Calcification In Halimeda Discoidea, K. E. Peach, M. S. Koch, Patricia Blackwelder
Marine & Environmental Sciences Faculty Articles
Ocean acidification (OA) effects on photophysiology and calcification were examined in Halimeda discoidea, a calcifying macroalga that produces tropical reef sediments. Photosynthetic parameters, including maximum photosynthetic rate (Pmax), photosynthetic efficiency (α) and compensating irradiance (Ic) were determined in short-term assays on live thalli after a 10 d exposure to 4 levels of CO2 partial pressures (pCO2; 491, 653, 982 and 1201 µatm) under saturating (300 µmol photons m-2 s-1) and sub-saturating (90 µmol photons m-2 s-1) irradiance in an aquaria study. Morphology …
Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill
Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill
OES Faculty Publications
Isotopic discrimination against 13C during photosynthesis is determined by a combination of environmental conditions and physiological mechanisms that control delivery of CO2 to RUBISCO. This study investigated the effects of light, flow, dissolved inorganic carbon (DIC) concentration, and its speciation, on photosynthetic carbon assimilation of Zostera marinaL. (eelgrass) using a combination of laboratory experiments and theoretical calculations leading to a mechanistic understanding of environmental conditions that influence leaf carbon uptake and determine leaf stable carbon isotope signatures δ13C. Photosynthesis was saturated with respect to flow at low velocity ~ 3 cm s-1, but …
Understanding Ocean Acidification Impacts On Organismal To Ecological Scales, Andreas J. Andersson, David I. Kline, Peter J. Edmunds, Stephen D. Archer, Nina Bednarsek, Robert C. Carpenter, Meg Chadsey, Philip Goldstein, Andrea G. Grottoli, Thomas P. Hurst, Andrew L. King, Janet E. Kübler, Ilsa B. Kuffner, Katherine R.M. Mackey, Bruce A. Menge, Adina Paytan, Ulf Riebesell, Astrid Schnetzer, Mark E. Warner, Richard C. Zimmerman
Understanding Ocean Acidification Impacts On Organismal To Ecological Scales, Andreas J. Andersson, David I. Kline, Peter J. Edmunds, Stephen D. Archer, Nina Bednarsek, Robert C. Carpenter, Meg Chadsey, Philip Goldstein, Andrea G. Grottoli, Thomas P. Hurst, Andrew L. King, Janet E. Kübler, Ilsa B. Kuffner, Katherine R.M. Mackey, Bruce A. Menge, Adina Paytan, Ulf Riebesell, Astrid Schnetzer, Mark E. Warner, Richard C. Zimmerman
OES Faculty Publications
Ocean acidification (OA) research seeks to understand how marine ecosystems and global elemental cycles will respond to changes in seawater carbonate chemistry in combination with other environmental perturbations such as warming, eutrophication, and deoxygenation. Here, we discuss the effectiveness and limitations of current research approaches used to address this goal. A diverse combination of approaches is essential to decipher the consequences of OA to marine organisms, communities, and ecosystems. Consequently, the benefits and limitations of each approach must be considered carefully. Major research challenges involve experimentally addressing the effects of OA in the context of large natural variability in seawater …
Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan
Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan
OES Faculty Publications
Dissolved inorganic phosphorus (DIP) concentrations in surface water of vast areas of the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (δ18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniques for studying P dynamics including 33P-based DIP turnover time estimates and percent of cells expressing alkaline phosphatase (AP) activity as measured by enzyme-labeling fluorescence are also used. In surface waters, δ18OPO4 values were lower than equilibrium by 3–6%, indicative of dissolved organic phosphorous (DOP) remineralization by extracellular enzymes. An isotope mass balance model using a variety of possible combinations of …
Δ13c Is A Signature Of Light Availability And Photosynthesis In Seagrass, Xingping Hu, David J. Burdige, Richard C. Zimmerman
Δ13c Is A Signature Of Light Availability And Photosynthesis In Seagrass, Xingping Hu, David J. Burdige, Richard C. Zimmerman
OES Faculty Publications
We explored the role of light-saturated (carbon-limited) photosynthesis on δ¹³C of turtlegrass (Thalassia testudinum Banks ex Konig) populations from the clear, blue waters of the Great Bahama Bank and the turbid, green waters of Florida Bay using field observations and radiative transfer models. Consistent with numerous previous observations, leaf δ¹³C decreased significantly with water depth in both regions. However the δ¹³C for Bahamas turtlegrass was 3 parts per thousand heavier than that for Florida Bay turtlegrass at equivalent depths, and broadband irradiance explained even less of the δ¹³C variations than depth. Instead, leaf δ¹³C showed a stronger relationship to …
Modeling The Vertical Distributions Of Downwelling Plane Irradiance And Diffuse Attenuation Coefficient In Optically Deep Waters, X. J. Pan, Richard C. Zimmerman
Modeling The Vertical Distributions Of Downwelling Plane Irradiance And Diffuse Attenuation Coefficient In Optically Deep Waters, X. J. Pan, Richard C. Zimmerman
OES Faculty Publications
The diffuse attenuation coefficient Kᵈ is critical to understand the vertical distribution of underwater downwelling irradiance (Eᵈ). Theoretically Eᵈ is composed of the direct solar beam and the diffuse sky irradiance. Applying the statistical results from Hydrolight radiative transfer simulations, Kᵈ is expressed into a mathematical equation (named as PZ06) integrated from the contribution of direct solar beam and diffuse sky irradiance with the knowledge of sky and water conditions. The percent root mean square errors (RMSE) for the vertical distribution of Eᵈ(z) under various sky and water conditions between PZ06 and Hydrolight results are typically less than 4%. Field …
Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 1. Model Configuration And Ecosystem Dynamics, Baris Salihoglu, Eileen E. Hofmann
Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 1. Model Configuration And Ecosystem Dynamics, Baris Salihoglu, Eileen E. Hofmann
OES Faculty Publications
The primary objective of this research is to investigate phytoplankton community response to variations in physical forcing and biological processes in the Cold Tongue region of the equatorial Pacific Ocean at 0N, 140W. This research objective was addressed using a one-dimensional multicomponent lower trophic level ecosystem model that includes detailed algal physiology, such as spectrally-dependent photosynthetic processes and iron limitation on algal growth. The ecosystem model is forced by a one-year (1992) time series of spectrally-dependent light, temperature, and water column mixing obtained from a Tropical Atmosphere-Ocean (TAO) Array mooring. Autotrophic growth is represented by five algal groups, which have …
Dynamics Of Carbon Allocation In A Deep-Water Population Of The Deciduous Kelp Pleurophycus Gardeneri (Laminariales), Clare M. Dominik, Richard C. Zimmerman
Dynamics Of Carbon Allocation In A Deep-Water Population Of The Deciduous Kelp Pleurophycus Gardeneri (Laminariales), Clare M. Dominik, Richard C. Zimmerman
OES Faculty Publications
Pleurophycus gardneri (Laminariales) is common in the low intertidal of the Northeast Pacific, but dominates many deep (30 to 40 m) rocky reefs in central California. Seasonal dynamics of productivity and resource allocation of a deep-water population of this deciduous, stipitate kelp were studied to understand how blade abscission affects the annual carbon budget. Patterns of growth, metabolism, and carbon storage and mobilization were measured monthly for 1 yr relative to in situ light and temperature, and used to model the annual carbon budget. The resulting carbon budget was used to determine if blade abscission effectively reduced respiratory demand during …
Impact Of Sea Grass Density On Carbonate Dissolution In Bahamian Sediments, David J. Burdige, Richard C. Zimmerman
Impact Of Sea Grass Density On Carbonate Dissolution In Bahamian Sediments, David J. Burdige, Richard C. Zimmerman
OES Faculty Publications
Carbonate dissolution has been widely observed in shallow water tropical sediments. However, sediment budgets C have generally not been closed with respect to the amount of acid required to produce the observed carbonate dissolution. Recently it has been suggested that enhanced oxygen transport into sediments through the roots and rhizomes of sea grasses might play a role in resolving this mass balance problem. We conducted studies of sea grass-carbonate sediment interactions around Lee Stocking Island, Exuma Islands, Bahamas to further examine this problem. Our studies showed that alkalinity, total dissolved inorganic carbon (ΣCO2) and Ca2+ increased with …
Top-Down Impact Through A Bottom-Up Mechanism. In Situ Effects Of Limpet Grazing On Growth, Light Requirements And Survival Of The Eelgrass Zostera Marina, Richard C. Zimmerman, Diana L. Steller, Donald G. Kohrs, Randall S. Alberte
Top-Down Impact Through A Bottom-Up Mechanism. In Situ Effects Of Limpet Grazing On Growth, Light Requirements And Survival Of The Eelgrass Zostera Marina, Richard C. Zimmerman, Diana L. Steller, Donald G. Kohrs, Randall S. Alberte
OES Faculty Publications
Temporal changes in abundance, size, productivity, resource allocation and light requirements of a subtidal eelgrass (Zostera marina L.) population were followed for 2 yr after the September 1993 appearance of a previously rare oval form of the commensal limpet Tectura depicta (Berry) in Monterey Bay, California, USA, By exclusively targeting the epidermis, limpet grazing impaired photosynthetic performance but left respiratory demand, meristematic growth and more than 90 % of the leaf biomass intact, The resulting low P:R ratios of grazed plants raised the light requirements for the maintenance of positive carbon balance almost 2-fold relative to healthy ungrazed plants …
Resource Allocation And Sucrose Mobilization In Light Limited Eelgrass Zostera Marina, Teresa Alcoverro, Richard C. Zimmerman, Donald G. Kohrs, Randall S. Alberte
Resource Allocation And Sucrose Mobilization In Light Limited Eelgrass Zostera Marina, Teresa Alcoverro, Richard C. Zimmerman, Donald G. Kohrs, Randall S. Alberte
OES Faculty Publications
This study evaluated the ability of Zostera marina L. (eelgrass) to balance the daily photosynthetic deficit by mobilization of carbon reserves stored in below-ground tissues during a period of extreme winter light limitation. A quantitative understanding of the mobilization process and its limitations is essential to the development of robust models predicting minimum light levels required to maintain healthy seagrass populations. Plants were grown in running seawater tanks under 2 light regimes. One treatment was provided with 2 h irradiance-saturated photosynthesis (Hsat) to produce severe Light Limitation, while control plants were grown under 7 h Hsat, …
Effect Of Light/Dark Transition On Carbon Translocation In Eelgrass Zostera Marina Seedlings, Richard C. Zimmerman, Randall S. Alberte
Effect Of Light/Dark Transition On Carbon Translocation In Eelgrass Zostera Marina Seedlings, Richard C. Zimmerman, Randall S. Alberte
OES Faculty Publications
Carbon translocation in the marine macrophyte Zostera marina L. (eelgrass) was investigated to elucidate the impact of light/dark transitions on sucrose partitioning between roots and shoots. After exposure of leaves to C-14-bicarbonate, the level of C-14-labelled photoassimilates increased monotonically in both leaves and fully aerobic roots of plants maintained in the light. Accumulation of C-14 in roots and leaves ceased abruptly when plants were transferred to darkness that induced root anaerobiosis even though C-14 levels remained high in the dark-exposed leaves. Thus, translocation of C-14 photoassimilates from shoots to roots was inhibited when roots became anoxic. Anoxia induced by light …