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Full-Text Articles in Physical Sciences and Mathematics
Interactions Of Bioactive Trace Metals In Shipboard Southern Ocean Incubation Experiments, Shannon M. Burns, Randelle M. Bundy, William Abbott, Zuzanna Abdala, Alexa R. Sterling, P. Dreux Chappell, Bethany D. Jenkins, Kristen N. Buck
Interactions Of Bioactive Trace Metals In Shipboard Southern Ocean Incubation Experiments, Shannon M. Burns, Randelle M. Bundy, William Abbott, Zuzanna Abdala, Alexa R. Sterling, P. Dreux Chappell, Bethany D. Jenkins, Kristen N. Buck
OES Faculty Publications
In the Southern Ocean, it is well‐known that iron (Fe) limits phytoplankton growth. Yet, other trace metals can also affect phytoplankton physiology. This study investigated feedbacks between phytoplankton growth and dissolved Fe, manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) concentrations in Southern Ocean shipboard incubations. Three experiments were conducted in September–October 2016 near the West Antarctic Peninsula: Incubations 1 and 3 offshore in the Antarctic Circumpolar Current, and Incubation 2 inshore in Bransfield Strait. Additions of Fe and/or vitamin B12 to inshore and offshore waters were employed and allowed assessment of metal (M) …
Estimating The Benthic Efflux Of Dissolved Iron On The Ross Sea Continental Shelf, C. M. Marsay, P. N. Sedwick, M. S. Dinniman, P. M. Barrett, S. L. Mack, D. J. Mcgillicuddy Jr.
Estimating The Benthic Efflux Of Dissolved Iron On The Ross Sea Continental Shelf, C. M. Marsay, P. N. Sedwick, M. S. Dinniman, P. M. Barrett, S. L. Mack, D. J. Mcgillicuddy Jr.
CCPO Publications
Continental margin sediments provide a potentially large but poorly constrained source of dissolved iron (dFe) to the upper ocean. The Ross Sea continental shelf is one region where this benthic supply is thought to play a key role in regulating the magnitude of seasonal primary production. Here we present data collected during austral summer 2012 that reveal contrasting low surface (0.08 +/- 0.07 nM) and elevated near-seafloor (0.74 +/- 0.47 nM) dFe concentrations. Combining these observations with results from a high-resolution physical circulation model, we estimate dFe efflux of 5.8 x 10(7) mol yr(-1) from the deeper portions (>400m) …
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 …
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 …
An Iron-Based Ecosystem Model Of The Central Equatorial Pacific, Carrie L. Leonard, Charles R. Mcclain, Ragu Murtugudde, Eileen E. Hofmann, Lawrence W. Harding Jr.
An Iron-Based Ecosystem Model Of The Central Equatorial Pacific, Carrie L. Leonard, Charles R. Mcclain, Ragu Murtugudde, Eileen E. Hofmann, Lawrence W. Harding Jr.
CCPO Publications
The central and eastern equatorial Pacific region is characterized by lower than expected phytoplankton biomass and primary production given the relatively high ambient nitrate concentrations. These unusual conditions have spawned several field programs and laboratory experiments to determine why this high nitrate-low chlorophyll pattern persists in this region. To synthesize the results from these field programs, as well as providing additional evidence in support of the iron hypothesis, we developed a one-dimensional, nine-component ecosystem model of 0 degrees N 140 degrees W. The model components include two phytoplankton size fractions, two zooplankton size fractions, two detrital size fractions, dissolved iron, …
Limitation Of Algal Growth By Iron Deficiency In The Australian Subantarctic Region, Peter N. Sedwick, Giacomo R. Ditullio, David A. Hutchins, Philip W. Boyd, F. Brian Griffiths, A. Clive Crossley, Thomas W. Trull, Bernard Queguiner
Limitation Of Algal Growth By Iron Deficiency In The Australian Subantarctic Region, Peter N. Sedwick, Giacomo R. Ditullio, David A. Hutchins, Philip W. Boyd, F. Brian Griffiths, A. Clive Crossley, Thomas W. Trull, Bernard Queguiner
OES Faculty Publications
In March 1998 we measured iron in the upper water column and conducted iron- and nutrient-enrichment bottle-incubation experiments in the open-ocean Subantarctic region southwest of Tasmania, Australia. In the Subtropical Convergence Zone (∼42°S, 142°E), silicic acid concentrations were low (< 1.5μM) in the upper water column, whereas pronounced vertical gradients in dissolved iron concentration (0.12-0.84 nM) were observed., presumably reflecting the interleaving of Subtropical and Subantarctic waters, and mineral aerosol input. Results of a bottle-incubation experiment performed at this location indicate that phytoplankton growth rates were limited by iron deficiency within the iron-poor layer of the euphotic zone. In the Subantarctic water mass (∼46.8°S, 142°E), low concentrations of dissolved iron (0.05-0.11nM) and silicic acid (< 1μM) were measured throughout the upper water column, and our experimental results indicate that algal growth was limited by iron deficiency. These observations suggest that availability of dissolved iron is a primary factor limiting phytoplankton growth over much of the Subantarctic Southern Ocean in the late summer and autumn.