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Articles 1 - 17 of 17
Full-Text Articles in Marine Biology
Detrital Neodymium And (Radio)Carbon As Complementary Sedimentary Bedfellows? The Western Arctic Ocean As A Testbed, Melissa S. Schwab, Jörg D. Rickli, Robie W. Macdonald, H. Rodger Harvey, Negar Haghipour, Timothy I. Eglinton
Detrital Neodymium And (Radio)Carbon As Complementary Sedimentary Bedfellows? The Western Arctic Ocean As A Testbed, Melissa S. Schwab, Jörg D. Rickli, Robie W. Macdonald, H. Rodger Harvey, Negar Haghipour, Timothy I. Eglinton
OES Faculty Publications
Interactions between organic and detrital mineral phases strongly influence both the dispersal and accumulation of terrestrial organic carbon (OC) in continental margin sediments. Yet the complex interplay among biological, chemical, and physical processes limits our understanding of how organo-mineral interactions evolve during sediment transfer and burial. In particular, diverse OC sources and complex hydrodynamic processes hinder the assessment of how the partnership of organic matter and its mineral host evolves during supply and dispersal over continental margins. In this study, we integrate new and compiled sedimentological (grain size, surface area), organic (%OC, OC-δ13C, OC-F14C), and inorganic …
Marine Phytoplankton Functional Types Exhibit Diverse Responses To Thermal Change, S. I. Anderson, A. D. Barton, Sophie Clayton, S. Dutkiewicz, T. A. Rynearson
Marine Phytoplankton Functional Types Exhibit Diverse Responses To Thermal Change, S. I. Anderson, A. D. Barton, Sophie Clayton, S. Dutkiewicz, T. A. Rynearson
OES Faculty Publications
Marine phytoplankton generate half of global primary production, making them essential to ecosystem functioning and biogeochemical cycling. Though phytoplankton are phylogenetically diverse, studies rarely designate unique thermal traits to different taxa, resulting in coarse representations of phytoplankton thermal responses. Here we assessed phytoplankton functional responses to temperature using empirically derived thermal growth rates from four principal contributors to marine productivity: diatoms, dinoflagellates, cyanobacteria, and coccolithophores. Using modeled sea surface temperatures for 1950-1970 and 2080-2100, we explored potential alterations to each group's growth rates and geographical distribution under a future climate change scenario. Contrary to the commonly applied Eppley formulation, our …
The Biogeochemical Cycling Of Iron, Copper, Nickel, Cadmium, Manganese, Cobalt, Lead, And Scandium In A California Current Experimental Study, Travis Mellett, Matthew T. Brown, P. Dreux Chappell, Carolyn Duckham, Jessica N. Fitzsimmons, Claire P. Till, Robert M. Sherrell, Maria T. Maldonado, Kristen N. Buck
The Biogeochemical Cycling Of Iron, Copper, Nickel, Cadmium, Manganese, Cobalt, Lead, And Scandium In A California Current Experimental Study, Travis Mellett, Matthew T. Brown, P. Dreux Chappell, Carolyn Duckham, Jessica N. Fitzsimmons, Claire P. Till, Robert M. Sherrell, Maria T. Maldonado, Kristen N. Buck
OES Faculty Publications
A 3-day shipboard incubation experiment was conducted in the California Current System in July 2014 to investigate the cycling of iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), and scandium (Sc) under a range of light and particle conditions. Filtered (< 0.2 μm) and unfiltered treatments were incubated under the following light conditions: Dark, light (“UV”), and light without the ultraviolet (UV) wavelengths (“noUV”). The experiment was sampled for carbon and Fe uptake rates, dissolved trace metal concentrations (Fe, Cu, Ni, Cd, Mn, Co, Pb, Sc), Fe and Cu speciation, size-fractionated concentrations of Cd and Fe, and diatom community composition from DNA sequencing. Exposure to UV light increased phytoplankton Fe uptake in the first 24 h of the incubation relative to the noUV treatment, suggesting that a fraction of the ambient ligand-bound Fe was photoreactive. Fe-binding organic ligand production was observed in the unfiltered light treatments in association with increasing chlorophyll a, and evidence for Cu-binding ligand production in these treatments was also observed. Biological uptake of Cd and Co was observed along with scavenging of dissolved Pb. Manganese appeared to be rapidly oxidized by Mn-oxidizing bacteria with concomitant drawdown of dissolved Ni. Scandium displayed similar trends to Fe, reinforcing the limited observations …
Frontiers In Otolith Chemistry: Insights, Advances And Applications, B. D. Walther, K. E. Limburg, C. M. Jones, J. J. Schaffler
Frontiers In Otolith Chemistry: Insights, Advances And Applications, B. D. Walther, K. E. Limburg, C. M. Jones, J. J. Schaffler
OES Faculty Publications
The rapid proliferation of publications employing chemical assays of fish hard parts, and otoliths in particular, has led to many novel insights into the migration patterns, life history strategies and mixed stock dynamics of fishes across the globe (Campana et al., 2000; Elsdon et al., 2008; Walther & Limburg, 2012). These insights include uncovering diverse migratory strategies within species and populations (Kerr et al., 2009; Hogan et al., 2014; Schoen et al., 2016), quantifying rates of mixing among stocks across management boundaries (Rooker et al., 2008; Walther & Thorrold, 2010) and estimating the relative …
Beyond Zar: The Use And Abuse Of Classification Statistics For Otolith Chemistry, C. M. Jones, M. Palmers, J. J. Schaffler
Beyond Zar: The Use And Abuse Of Classification Statistics For Otolith Chemistry, C. M. Jones, M. Palmers, J. J. Schaffler
OES Faculty Publications
Classification method performance was evaluated using otolith chemistry of juvenile Atlantic menhaden Brevoortia tyrannus when assumptions of data normality were met and were violated. Four methods were tested [linear discriminant function analysis (LDFA), quadratic discriminant function analysis (QDFA), random forest (RF) and artificial neural networks (ANN)] using computer simulation to determine their performance when variable-group means ranged from small to large and their performance under conditions of typical skewness to double the amount of skewness typically observed. Using the kappa index, the parametric methods performed best after applying appropriate data transformation, gaining 2% better performance with LDFA performing slightly better …
Using Ammonium Pore Water Profiles To Assess Stoichiometry Of Deep Remineralization Processes In Methanogenic Continental Margin Sediments, David J. Burdige, Tomoko Komada
Using Ammonium Pore Water Profiles To Assess Stoichiometry Of Deep Remineralization Processes In Methanogenic Continental Margin Sediments, David J. Burdige, Tomoko Komada
OES Faculty Publications
In many continental margin Sediments, a deep reaction zone exists which is separated from remineralization processes near the sediment surface. Here, methane diffuses upward to a depth where it is oxidized by downwardly diffusing sulfate. However, the methane sources that drive this anaerobic oxidation of methane (AOM) in the sulfate-methane transition zone (SMT) may vary among sites. In particular, these sources can be thought of as either (i) "internal" sources from in situ methanogenesis (regardless of where it occurs in the sediment column) that are ultimately coupled to organic matter deposition and burial, or (ii) "external" sources such as hydrocarbon …
Controls On Dissolved Cobalt In Surface Waters Of The Sargasso Sea: Comparisons With Iron And Aluminum, R. U. Shelley, Peter N. Sedwick, T. S. Bibby, P. Cabedo-Sanz, T. M. Church, R. J. Johnson, A. I. Macey, C. M. Marsay, E. R. Sholkovitz, S. J. Ussher, P. J. Worsfold, M. C. Lohan
Controls On Dissolved Cobalt In Surface Waters Of The Sargasso Sea: Comparisons With Iron And Aluminum, R. U. Shelley, Peter N. Sedwick, T. S. Bibby, P. Cabedo-Sanz, T. M. Church, R. J. Johnson, A. I. Macey, C. M. Marsay, E. R. Sholkovitz, S. J. Ussher, P. J. Worsfold, M. C. Lohan
OES Faculty Publications
Dissolved cobalt (dCo), iron (dFe) and aluminum (dAl) were determined in water column samples along a meridional transect (∼31°N to 24°N) south of Bermuda in June 2008. A general north-to-south increase in surface concentrations of dFe (0.3-1.6 nM) and dAl (14-42 nM) was observed, suggesting that aerosol deposition is a significant source of dFe and dAl, whereas no clear trend was observed. for near-surface dCo concentrations. Shipboard aerosol samples indicate fractional solubility values of 8-100% for aerosol Co, which are significantly higher than corresponding estimates of the solubility of aerosol Fe (0.44-45%). Hydrographic observations and analysis of time series rain …
Influence Of Irradiance And Iron On The Growth Of Colonial Phaeocystic Antarctica: Implications For Seasonal Bloom Dynamics In The Ross Sea, Antarctica, Nathan S. Garcia, Peter N. Sedwick, Giacomo R. Ditullio
Influence Of Irradiance And Iron On The Growth Of Colonial Phaeocystic Antarctica: Implications For Seasonal Bloom Dynamics In The Ross Sea, Antarctica, Nathan S. Garcia, Peter N. Sedwick, Giacomo R. Ditullio
OES Faculty Publications
Laboratory culture experiments were used to investigate the growth rate of colonial Phaeocystis anarctica as a function of irradiance and dissolved iron concentration. The experiments were conducted with a P. antarctica strain isolated from the southern Ross Sea, Antarctica, and made use of natural, low-iron (P. antarctica attained an average maximum cell-specific growth rate of 0.37 d-1at an irradiance of 68 μE m-2s-1, above which growth rates decreased to 0.27 d-1 at an irradiance of 314 μE m-2s-1. The dependence of growth rate on ambient dissolved iron concentration was …
Influence Of Short-Term Variations In Food On Survival Of Crassotrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A, Bochenek, John M. Klinck, Eileen E. Hofmann
Influence Of Short-Term Variations In Food On Survival Of Crassotrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A, Bochenek, John M. Klinck, Eileen E. Hofmann
OES Faculty Publications
A biochemically-based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster, Crassostrea gigas. The model defines larvae in terms of their protein, lipid, carbohydrate, and ash content and includes variation in growth efficiency and egg quality to better simulate cohort population dynamics. Changes in tissue composition occur as the larva grows and in response to the biochemical composition of the food. The premise behind this modeling study was that certain periods of larval life are more critical than others with respect to the availability of food and that food quality is as …
Demographic Assessment Of The Blue Crab (Callinectes Sapidus) In Chesapeake Bay Using Extractable Lipofuscins As Age Markers, Se-Jong Ju, David H. Secor, H. Rodger Harvey
Demographic Assessment Of The Blue Crab (Callinectes Sapidus) In Chesapeake Bay Using Extractable Lipofuscins As Age Markers, Se-Jong Ju, David H. Secor, H. Rodger Harvey
OES Faculty Publications
The blue crab (Callinectes sapidus) plays an important economic and ecological role in estuaries and coastal habitats from the Gulf of Mexico to the east coast of North America, but demographic assessments are limited by length-based methods. We applied an alternative aging method using biochemical measures of metabolic byproducts (lipofuscins) sequestered in the neural tissue of eyestalks to examine population age structure. From Chesapeake Bay, subsamples of animals collected from the 1998-99 (n-769) and 1999-2000 (n=367) winter dredge surveys were collected and lipofuscin was measured. Modal analysis of the lipofuscin index provided separation into three modes, whereas carapace-width …
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 …
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 …
Control Of Phytoplankton Growth By Iron And Silicic Acid Availability In The Subantarctic Ocean: Experimental Results From The Saz Project, D. A. Hutchins, Peter N. Sedwick, G. R. Ditullio, P. W. Boyd, B. Queguiner, F. B. Griffiths, C. Crossley
Control Of Phytoplankton Growth By Iron And Silicic Acid Availability In The Subantarctic Ocean: Experimental Results From The Saz Project, D. A. Hutchins, Peter N. Sedwick, G. R. Ditullio, P. W. Boyd, B. Queguiner, F. B. Griffiths, C. Crossley
OES Faculty Publications
Subantarctic Southern Ocean surface waters in the austral summer and autumn are characterized by high concentrations of nitrate and phosphate but low concentrations of dissolved iron (Fe, similar to0.05 nM) and silicic acid (Si, <1 muM). During the Subantarctic Zone AU9706 cruise in March 1998 we investigated the relative importance of Fe and Si in controlling phytoplankton growth and species composition at a station within the subantarctic water mass (46.8degreesS, 142degreesE) using shipboard bottle incubation experiments. Treatments included unamended controls; 1.9 nM added iron (+Fe); 9 muM added silicic acid (+Si); and 1.9 nM addediron plus 9 muM added silicic acid (+Fe+Si). We followed a detailed set of biological and biogeochemical parameters over 8 days. Fe added alone clearly increased community growth rates and nitrate drawdown and altered algal community composition relative to control treatments. Surprisingly, small, lightly silicified pennate diatoms grew when Fe was added either with or without Si, despite the extremely low ambient silicic acid concentrations. Pigment analyses suggest that lightly silicified chrysophytes (type 4 haptophytes) may have preferentially responded to Si added either with or without Fe. However, for many of the parameters measured the +Fe+Si treatments showed large increases relative to both the +Fe and +Si treatments. Our results suggest that iron is the proximate limiting nutrient for chlorophyll production, photosynthetic efficiency, nitrate drawdown, and diatom growth, but that Si also exerts considerable control over algal growth and species composition. Both nutrients together are needed to elicit a maximum growth response, suggesting that both Fe and Si play important roles in structuring the subantarctic phytoplankton community.
Biochemical Composition Of Particles And Dissolved Organic Matter Slong An Estuarine Gradient: Sources And Implications For Dom Reactivity, Antonio Mannino, H. Rodger Harvey
Biochemical Composition Of Particles And Dissolved Organic Matter Slong An Estuarine Gradient: Sources And Implications For Dom Reactivity, Antonio Mannino, H. Rodger Harvey
OES Faculty Publications
The chemical composition of high molecular weight dissolved organic matter (DOM) and particulate organic matter (POM) was examined along the salinity gradient of the Delaware Estuary. DOM was collected and fractionated by tangential-flow ultrafiltration into 1-30 kDa (HDOM; high molecular weight) and 30 kDa to 0.2 μm (VHDOM; very high molecular weight) and compared to particles collected in parallel. Polysaccharides comprised 12-43% of particulate organic carbon (POC), 30-56% of VHDOM carbon, and 7.5-19% of HDOM carbon. Hydrolyzable amino acids comprised 17-38% of POC, 5.4-12% of VHDOM carbon, and 1.5-4.2% of HDOM carbon. Only 7-43% of dissolved organic nitrogen in VHDOM …
Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey
Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey
OES Faculty Publications
The blue crab Callinectes sapidus is an economically and ecologically important species in many temperate estuaries, yet stock assessments have been limited to length-based methods for demographic analyses. We evaluated the potential of age pigments (lipofuscins) sequestered in neural tissue of eye-stalks and brains to estimate the age of blue crabs collected from Chesapeake Bay and Chincoteague Bay. The rate of lipofuscin accumulation was determined using crabs of known age reared in the laboratory. Age pigments were extracted from neural tissues (eye-stalk or brain), quantified, and normalized to protein content to allow comparisons across tissue types and crab sizes. Field-collected …
The Biogeochemical Cycling Of Dissolved Organic Nitrogen In Estuarine Sediments, David J. Burdige, Shilong Zheng
The Biogeochemical Cycling Of Dissolved Organic Nitrogen In Estuarine Sediments, David J. Burdige, Shilong Zheng
OES Faculty Publications
Benthic fluxes and pore-water profiles of dissolved organic nitrogen and carbon (DON and DOC, respectively) were determined in seasonal studies at contrasting sites in Chesapeake Bay. Pore-water dissolved organic matter (DOM) concentrations were elevated over bottom-water values, generally increased with depth, and ranged from 15 to similar to 160 μM for DON and ~200-2000 μM for DOC. Pore-water DOM concentrations and the C:N ratio of this material showed spatial (depth) and temporal changes that varied among the sites studied. These trends appeared to be related to differences in the types of sediment organic matter (SOM) undergoing remineralization, as well as …
Trophic Transfer Of Fatty Acids, Sterols, And A Triterpenoid Alcohol Between Bacteria, A Ciliate, And The Copepod Acartia Tonsa, Melissa C. Ederington, George B. Mcmanus, H. Rodger Harvey
Trophic Transfer Of Fatty Acids, Sterols, And A Triterpenoid Alcohol Between Bacteria, A Ciliate, And The Copepod Acartia Tonsa, Melissa C. Ederington, George B. Mcmanus, H. Rodger Harvey
OES Faculty Publications
The incorporation of lipids into the copepod Acartia tonsa and its eggs was measured when it was fed either a bacterivorous ciliate (Pleuronema sp.) or a diatom (Thalassiosira weissflogii). Egg production was 10-fold higher on the diatom diet, whereas hatch success of eggs was the same for algal and ciliate diets. Adult copepods fed diatoms contained more total fatty acid and sterols than copepods fed the ciliate diet, and individual lipids reflected the dietary source. Eggs from diatom-fed copepods had fewer fatty acids but more sterols than eggs from copepods on a ciliate diet. Ciliate-fed copepods and …