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Full-Text Articles in Life Sciences
Levels Of Autotrophy And Heterotrophy In Mesophotic Corals Near The End Photic Zone, Amy Carmignani, Veronica Z. Radice, Kathryn M. Mcmahon, Alex I. Holman, Karen Miller, Kliti Grice, Zoe Richards
Levels Of Autotrophy And Heterotrophy In Mesophotic Corals Near The End Photic Zone, Amy Carmignani, Veronica Z. Radice, Kathryn M. Mcmahon, Alex I. Holman, Karen Miller, Kliti Grice, Zoe Richards
Biological Sciences Faculty Publications
Mesophotic corals live at ~30-150 m depth and can sustain metabolic processes under light-limited conditions by enhancing autotrophy through specialized photoadaptations or increasing heterotrophic nutrient acquisition. These acclimatory processes are often species-specific, however mesophotic ecosystems are largely unexplored and acclimation limits for most species are unknown. This study examined mesophotic coral ecosystems using a remotely operated vehicle (Ashmore Reef, Western Australia at 40–75m depth) to investigate the trophic ecology of five species of scleractinian coral (from genera Leptoseris, Pachyseris, and Craterastrea) using stable isotope analyses (δ13C and δ15N) of host and symbiont tissues …
Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins
Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins
OES Faculty Publications
The growth of diatoms in the Southern Ocean, especially the region surrounding the West Antarctic Peninsula, is frequently constrained by low dissolved iron and other trace metal concentrations. This challenge may be overcome by mutualisms between diatoms and co-occurring associated bacteria, in which diatoms produce organic carbon as a substrate for bacterial growth, and bacteria produce siderophores, metal-binding ligands that can supply diatoms with metals upon uptake as well as other useful secondary compounds for diatom growth like vitamins. To examine the relationships between diatoms and bacteria in the plankton (diatom) size class (> 3 mu m), we sampled both …
Isotopic Evidence For Sources Of Dissolved Carbon And The Role Of Organic Matter Respiration In The Fraser River Basin, Canada, Britta M. Voss, Timothy I. Eglinton, Bernhard Peucker-Ehrenbrink, Valier Galy, Susan Q. Lang, Cameron Mcintyre, Robert G.M. Spencer, Ekaterina Bulygina, Zhaohui Aleck Wang, Katherine A. Guay
Isotopic Evidence For Sources Of Dissolved Carbon And The Role Of Organic Matter Respiration In The Fraser River Basin, Canada, Britta M. Voss, Timothy I. Eglinton, Bernhard Peucker-Ehrenbrink, Valier Galy, Susan Q. Lang, Cameron Mcintyre, Robert G.M. Spencer, Ekaterina Bulygina, Zhaohui Aleck Wang, Katherine A. Guay
OES Faculty Publications
Sources of dissolved and particulate carbon to the Fraser River system vary significantly in space and time. Tributaries in the northern interior of the basin consistently deliver higher concentrations of dissolved organic carbon (DOC) to the main stem than other tributaries. Based on samples collected near the Fraser River mouth throughout 2013, the radiocarbon age of DOC exported from the Fraser River does not change significantly across seasons despite a spike in DOC concentration during the freshet, suggesting modulation of heterogeneous upstream chemical and isotopic signals during transit through the river basin. Dissolved inorganic carbon (DIC) concentrations are highest in …
Geomorphic Gradients In Shallow Seagrass Carbon Stocks, Jahson Berhane Alemu, Siti Maryam Yaakub, Erik S. Yando, Rachel Yu San Lau, Cheng Chang Lim, Jun Yu Puah, Daniel A. Friess
Geomorphic Gradients In Shallow Seagrass Carbon Stocks, Jahson Berhane Alemu, Siti Maryam Yaakub, Erik S. Yando, Rachel Yu San Lau, Cheng Chang Lim, Jun Yu Puah, Daniel A. Friess
Biological Sciences Faculty Publications
Seagrass meadows are important sinks of organic carbon (Corg), in particular the near-surface Corg pool (≤ 15 cm) compared to deeper sediments. Near-surface carbon is highly susceptible to disturbance and loss to the atmosphere, however, inadequate accounting for variability in this pool of carbon limits their uptake into carbon accounting frameworks. We therefore investigated the spatial variability in seagrass near-surface Corg and biomass Corg across different geomorphic (estuary, lagoonal and reef-associated) and community typologies (pioneer and persistent). Near-surface Corg stock in vegetated areas (25.78 Mg Corg ha−1 ± 26.64) was twice that …
Temporal Stability Of Seagrass Extent, Leaf Area, And Carbon Storage In St. Joseph Bay, Florida: A Semi-Automated Remote Sensing Analysis, Marie Cindy Lebrasse, Blake A. Schaeffer, Megan M. Coffer, Peter J. Whitman, Richard C. Zimmerman, Victoria J. Hill, Kazi A. Islam, Jiang Li, Christopher L. Osburn
Temporal Stability Of Seagrass Extent, Leaf Area, And Carbon Storage In St. Joseph Bay, Florida: A Semi-Automated Remote Sensing Analysis, Marie Cindy Lebrasse, Blake A. Schaeffer, Megan M. Coffer, Peter J. Whitman, Richard C. Zimmerman, Victoria J. Hill, Kazi A. Islam, Jiang Li, Christopher L. Osburn
OES Faculty Publications
Seagrasses are globally recognized for their contribution to blue carbon sequestration. However, accurate quantification of their carbon storage capacity remains uncertain due, in part, to an incomplete inventory of global seagrass extent and assessment of its temporal variability. Furthermore, seagrasses are undergoing significant decline globally, which highlights the urgent need to develop change detection techniques applicable to both the scale of loss and the spatial complexity of coastal environments. This study applied a deep learning algorithm to a 30-year time series of Landsat 5 through 8 imagery to quantify seagrass extent, leaf area index (LAI), and belowground organic carbon (BGC) …
Examining Ecological Succession Of Diatoms In California Current System Cyclonic Mesoscale Eddies, Zuzanna M. Abdala, Sophie Clayton, Sveinn V. Einarsson, Kimberly Powell, Claire P. Till, Tyler H. Coale, P. Dreux Chappell
Examining Ecological Succession Of Diatoms In California Current System Cyclonic Mesoscale Eddies, Zuzanna M. Abdala, Sophie Clayton, Sveinn V. Einarsson, Kimberly Powell, Claire P. Till, Tyler H. Coale, P. Dreux Chappell
OES Faculty Publications
The California Current System is a diatom-dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental …
Composition Of Dissolved Organic Matter In Pore Waters Of Anoxic Marine Sediments Analyzed By 1h Nuclear Magnetic Resonance Spectroscopy, Christina A. Fox, Hussain A. Abdulla, David J. Burdige, James P. Lewicki, Tomoko Komada
Composition Of Dissolved Organic Matter In Pore Waters Of Anoxic Marine Sediments Analyzed By 1h Nuclear Magnetic Resonance Spectroscopy, Christina A. Fox, Hussain A. Abdulla, David J. Burdige, James P. Lewicki, Tomoko Komada
OES Faculty Publications
Marine sediments are globally significant sources of dissolved organic matter (DOM) to the oceans, but the biogeochemical role of pore-water DOM in the benthic and marine carbon cycles remains unclear due to a lack of understanding about the molecular composition of DOM. To help fill this knowledge gap, we used 1H nuclear magnetic resonance (NMR) spectroscopy to examine depth variability in the composition of pore-water DOM in anoxic sediments of Santa Barbara Basin, California Borderland. Proton detected spectra were acquired on whole samples without pre-concentration to avoid preclusion of any DOM components from the analytical window. Broad unresolved resonance (operationally …
Eukaryotic Microbes, Principally Fungi And Labyrinthulomycetes, Dominate Biomass On Bathypelagic Marine Snow, Alexander B. Bochdansky, Melissa A. Clouse, Gerhard J. Herndl
Eukaryotic Microbes, Principally Fungi And Labyrinthulomycetes, Dominate Biomass On Bathypelagic Marine Snow, Alexander B. Bochdansky, Melissa A. Clouse, Gerhard J. Herndl
OES Faculty Publications
In the bathypelagic realm of the ocean, the role of marine snow as a carbon and energy source for the deep-sea biota and as a potential hotspot of microbial diversity and activity has not received adequate attention. Here, we collected bathypelagic marine snow by gentle gravity filtration of sea water onto μm filters from similar to 1000 to 3900 m to investigate the relative distribution of eukaryotic microbes. Compared with sediment traps that select for fast-sinking particles, this method collects particles unbiased by settling velocity. While prokaryotes numerically exceeded eukaryotes on marine snow, eukaryotic microbes belonging to two very distant …
Studies On Hydroxyl Radical Formation And Correlated Photoflocculation Process Using Degraded Wood Leachate As A Cdom Source, Luni Sun, Kenneth Mopper
Studies On Hydroxyl Radical Formation And Correlated Photoflocculation Process Using Degraded Wood Leachate As A Cdom Source, Luni Sun, Kenneth Mopper
Chemistry & Biochemistry Faculty Publications
In this study, we examined hydroxyl radical (•OH) formation with respect to photoreactivity of colored dissolved organic matter (CDOM), the Fenton reaction, and photoflocculation using leachate from decaying wood. The relationship between •OH photoproduction rate and leachate optical properties (UV-visible absorption and fluorescence excitation-emission matrices (EEMS)) was studied during irradiation using a UV solar simulator. The results showed that the •OH photochemical formation rate is strongly related to humic-like fluorescence as characterized by parallel factor analysis (PARAFAC), and that these fluorescence components are more photolabile than most of the other CDOM components. Fourier transform infrared spectroscopy (FT-IR) indicated the photodegradation …
Imber- Research For Marine Sustainability: Synthesis And The Way Forward, Eileen Hofmann, Alida Bundy, Ken Drinkwater, Alberto R. Piola, Bernard Avril, Carol Robinson
Imber- Research For Marine Sustainability: Synthesis And The Way Forward, Eileen Hofmann, Alida Bundy, Ken Drinkwater, Alberto R. Piola, Bernard Avril, Carol Robinson
CCPO Publications
The Integrated Marine Biogeochemistry and Ecosystem Research (IMBER) project aims at developing a comprehensive understanding of and accurate predictive capacity of ocean responses to accelerating global change and the consequent effects on the Earth system and human society. Understanding the changing ecology and biogeochemistry of marine ecosystems and their sensitivity and resilience to multiple drivers, pressures and stressors is critical to developing responses that will help reduce the vulnerability of marine-dependent human communities. This overview of the IMBER project provides a synthesis of project achievements and highlights the value of collaborative, interdisciplinary, integrated research approaches as developed and implemented through …
Grazing Impacts Of Diverse Zooplankton Taxa On Thin Layers, Alexander Bochdansky
Grazing Impacts Of Diverse Zooplankton Taxa On Thin Layers, Alexander Bochdansky
OES Faculty Publications
The US Navy needs to know how distributions and abundances of light-scattering and sound-scattering organisms in the ocean vary in space and time, particularly in the vertical dimension. Recent field observations have shown that many biological properties may vary substantially over small e.g. centimeter scales, commonly referred to as thin layers e.g. Cowles et al. 1998, 1999, Hanson Donaghay 1998, Holliday et al. 1999, Dekshenieks et al. 2001, Alldredge et al. 2002, Rines et al. 2002. Our previous ONR-funded research has allowed us to begin to understand how zooplankton interact with thin layers and how they can take advantage of …
Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper
Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper
Chemistry & Biochemistry Faculty Publications
We performed laboratory studies to determine the effects of salinity on the photodegradation of dissolved organic matter (DOM) from the Great Dismal Swamp, Virginia, an important source of terrestrial DOM to the lower Chesapeake Bay. Samples were created by mixing Great Dismal Swamp water (ionic strength approximate to 0 mol L-1) with modified artificial seawater solutions of differing salinities while keeping the final dissolved organic carbon (DOC) concentration constant. These samples were then irradiated for 24 h in a light box providing ultraviolet (UV) light similar to that of natural sunlight. Light absorbance and DOC concentrations decreased after …
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 …
Effects Of Iron, Silicate, And Light On Dimethylsulfoniopropionate Production In The Australian Subantarctic Zone, G. R. Ditullio, P. N. Sedwick, D. R. Jones, P. W. Boyd, A. C. Crossley, D. A. Hutchins
Effects Of Iron, Silicate, And Light On Dimethylsulfoniopropionate Production In The Australian Subantarctic Zone, G. R. Ditullio, P. N. Sedwick, D. R. Jones, P. W. Boyd, A. C. Crossley, D. A. Hutchins
OES Faculty Publications
Shipboard bottle incubation experiments were performed to investigate the effects of iron, light, and silicate on algal production of particulate dimethylsulfoniopropionate (DMSPp) in the Subantarctic Zone (SAZ) south of Tasmania during March 1998. Iron enrichment resulted in threefold to ninefold increases in DMSPp concentrations relative to control treatments, following 7 and 8-day incubation experiments. Additions of Fe and Si preferentially stimulated the growth of lightly-silicified pennate diatoms and siliceous haptophytes, respectively, to which we attribute the increased DMSPp production in the incubation bottles. Both of these algal groups were previously believed to be low DMSPp …
Absorption Efficiencies And Biochemical Fractionation Of Assimilated Compounds In The Cold Water Appendicularian Oikopleura Vanhoeffeni, Alexander B. Bochdansky, Don Deibel, Richard B. Rivkin
Absorption Efficiencies And Biochemical Fractionation Of Assimilated Compounds In The Cold Water Appendicularian Oikopleura Vanhoeffeni, Alexander B. Bochdansky, Don Deibel, Richard B. Rivkin
OES Faculty Publications
Using Ge-68:C-14 dual-labeling, we investigated the absorption efficiency of diatom carbon for the cold water appendicularian Oikopleura vanhoeffeni. The absorption efficiency of bulk carbon (mean = 67%) was not influenced by body size or ingestion rate. For the first time for a pelagic tunicate, food and feces were fractionated into their major biochemical constituents (i.e., low-molecular-weight compounds, lipid, protein, and polysaccharide), allowing calculation of absorption efficiencies for each fraction. Low-molecular-weight compounds and proteins were preferentially absorbed over lipids and polysaccharides. However, predicted C:N ratios of the fecal pellets of O. vanhoeffeni were in the lower range of C:N ratios …