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Oceanography

2005

Articles 1 - 15 of 15

Full-Text Articles in Earth Sciences

Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen Dec 2005

Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen

All Faculty Scholarship for the College of the Sciences

Mineral aerosol deposition is the dominant source of iron to the open ocean. Soil iron is typically insoluble and understanding the atmospheric processes that convert insoluble iron to the more soluble forms observed over the oceans is crucial. In this paper, we model several proposed processes for the conversion of Fe(III) to Fe(II), and compare with cruise observations. The comparisons show that the model results in similar averaged magnitudes of iron solubility as measured during 8 cruises in 2001–2003. Comparisons show that results of cases including cloud, SO2 and hematite processing are better than the other approaches used using …

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Interaction Of Sea Ice Sediments And Surface Sea Water In The Arctic Ocean: Evidence From Excess 210Pb, M. Baskaran Jun 2005

Interaction Of Sea Ice Sediments And Surface Sea Water In The Arctic Ocean: Evidence From Excess 210Pb, M. Baskaran

Environmental Science and Geology Faculty Research Publications

We measured the activities of 210Pb, 226Ra, 238U and 137Cs in a suite of ice-rafted sediments (IRS) from the Arctic Ocean in an attempt to assess the interaction of sea ice sediments and surface water. The concentrations of these nuclides were compared to those of the benthic sediments in the coastal and shelf regions of the Arctic Ocean, which are believed to be the major source region for the IRS. The concentration factors (CF = activity of a nuclide in IRS/average activity in benthic sediments) are ∼1 and 4-92 for 137Cs and 210Pb, respectively. …

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Women In Oceanography: Women Of The Academy And The Sea, Suzanne O'Connell, Mary Anne Holmes Mar 2005

Women In Oceanography: Women Of The Academy And The Sea, Suzanne O'Connell, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

Women have played an active role in all areas of oceanography. Defining the number of women oceanographers is not an easy task because the discipline is so broad and the boundaries between subdisciplines are not always distinct.

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Iron In The Sargasso Sea (Bermuda Atlantic Time-Series Study Region) During Summer: Eolian Imprint, Spatiotemporal Variability, And Ecological Implications, Peter N. Sedwick, T. M. Church, A. R. Bowie, C. M. Marsay, S. J. Ussher, K. M. Achilles, P. J. Lethaby, R. J. Johnson, M. M. Sarin, D. J. Mcgillicuddy Jan 2005

Iron In The Sargasso Sea (Bermuda Atlantic Time-Series Study Region) During Summer: Eolian Imprint, Spatiotemporal Variability, And Ecological Implications, Peter N. Sedwick, T. M. Church, A. R. Bowie, C. M. Marsay, S. J. Ussher, K. M. Achilles, P. J. Lethaby, R. J. Johnson, M. M. Sarin, D. J. Mcgillicuddy

OES Faculty Publications

We report iron measurements for water column and aerosol samples collected in the Sargasso Sea during July-August 2003 (summer 2003) and April-May 2004 (spring 2004). Our data reveal a large seasonal change in the dissolved iron (dFe) concentration of surface waters in the Bermuda Atlantic Time-series Study region, from ∼1-2nM in summer 2003, when aerosol iron concentrations were high (mean 10 nmol/m-3), to ∼0.1-0.2nM in spring 2004, when aerosol iron concentrations were low (mean 0.64 nmol/m-3). During summer 2003, we observed an increase of ∼0.6nM in surface water dFe concentrations over 13 days, presumably due to …

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Monsoon-Driven Biogeochemical Processes In The Arabian Sea, Jerry D. Wiggert, Raleigh Hood, Karl Banse, John Kindle Jan 2005

Monsoon-Driven Biogeochemical Processes In The Arabian Sea, Jerry D. Wiggert, Raleigh Hood, Karl Banse, John Kindle

Faculty Publications

Although it is nominally a tropical locale, the semiannual wind reversals associated with the Monsoon system of the Arabian Sea result annually in two distinct periods of elevated biological activity. While in both cases monsoonal forcing drives surface layer nutrient enrichment that supports increased rates of primary productivity, fundamentally different entrainment mechanisms are operating in summer (Southwest) and winter (Northeast) Monsoons. Moreover, the intervening intermonsoon periods, during which the region relaxes toward oligotrophic conditions more typical of tropical environments, provide a stark contrast to the dynamic biogeochemical activity of the monsoons. The resulting spatial and temporal variability is great and …

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Simulation Of Turbidity Maximums In The York River, Virginia, Jae-Il Kwon Jan 2005

Simulation Of Turbidity Maximums In The York River, Virginia, Jae-Il Kwon

Dissertations, Theses, and Masters Projects

Two of the most important processes in cohesive sediment transport, erosion rate and settling velocity, were the focus of this study. Settling velocities were estimated by the Owen tube method and the acoustic Doppler velocimeter (ADV) method. A novel erosion model, namely a constant erosion rate model, was implemented in a three-dimensional hydrodynamic eutrophication model (HEM-3D) to simulate the turbidity maximums in the York River system, Virginia. Two one-month periods of model simulations were conducted to mimic typical dry (November--December, 2001) and wet (March--April, 2002) seasons. In order to have enough data to verify the model, four slack water surveys …

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Burial Of Terrestrial Organic Matter In Marine Sediments: A Re-Assessment, David J. Burdige Jan 2005

Burial Of Terrestrial Organic Matter In Marine Sediments: A Re-Assessment, David J. Burdige

OES Faculty Publications

Calculations based on recent observations indicate that approximately one third of the organic matter presently being buried in marine sediments may be of terrestrial origin, with the majority of this terrestrial organic matter (TOM) burial occurring in muddy, deltaic sediments. These calculations further suggest that the remineralization of terrestrial organic matter in the oceans is also much less efficient than that of marine organic matter. These two underappreciated observations have important implications in terms of our understanding of the controls on the global carbon cycle. From a paleoceanographic perspective, the results presented here also suggest that changes in TOM burial …

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Sources Of Sedimentary Organic Matter In The Mississippi River And Adjacent Gulf Of Mexico, Elizabeth J. Waterson Jan 2005

Sources Of Sedimentary Organic Matter In The Mississippi River And Adjacent Gulf Of Mexico, Elizabeth J. Waterson

Dissertations, Theses, and Masters Projects

The development of accurate carbon budgets, as well as global climate models with predictive capabilities, requires an understanding of the delivery and fate of terrigenous carbon in the environment. Understanding the extent to which estuarine and continental shelf processes alter carbon transfer between marine and terrestrial systems, including estimates of organic matter accumulation in coastal sediments, is poorly known. Organic carbon and nutrients exported to the adjacent Gulf of Mexico by the Mississippi River are influenced by biological and physical processes including remineralization, hydrodynamic sorting, seabed mixing and bioturbation, and burial. These complex processes make it difficult to know the …

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A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu Jan 2005

A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu

OES Faculty Publications

A distinctive seasonal pattern in phytoplankton biomass was observed at the South East Asian Time series Study (SEATS) station (18°N, 116°E) in the northern South China Sea (SCS). Surface chlorophyll-a, depth integrated chlorophyll-a and primary production were elevated to 0.3 mg/m3, ~35 mg/m2 and 300 mg-C/m2/d, respectively, in the winter but stayed low, at 0.1 mg/m3, ~15 mg/m2 and 110 mg-C/m2/d as commonly found in other low latitude waters, in the rest of the year. Concomitantly, soluble reactive phosphate and nitrate+nitrite in the mixed layer also became …

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Variability Of Sea Ice Cover In The Chukchi Sea (Western Arctic Ocean) During The Holocene, Anne De Vernal, Claude Hillaire-Marcel, Dennis A. Darby Jan 2005

Variability Of Sea Ice Cover In The Chukchi Sea (Western Arctic Ocean) During The Holocene, Anne De Vernal, Claude Hillaire-Marcel, Dennis A. Darby

OES Faculty Publications

Dinocysts from cores collected in the Chukchi Sea from the shelf edge to the lower slope were used to reconstruct changes in sea surface conditions and sea ice cover using modern analogue techniques. Holocene sequences have been recovered in a down-slope core (B15: 2135 m, 75°44'N, sedimentation rate of ~1cm kyr-1) and in a shelf core (P1: 201 m, 73°41'N, sedimentation rate of ~22 cm kyr-1). The shelf record spanning about 8000 years suggests high-frequency centennial oscillations of sea surface conditions and a significant reduction of the sea ice at circa 6000 and 2500 calendar (cal) …

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Hydrographic And Biological Changes In The Taiwan Strait During The 1997-1998 El Niño Winter, S. Shang, C. Zhang, H. Hong, Q. Liu, G. T. F. Wong, C. Hu, B. Huang Jan 2005

Hydrographic And Biological Changes In The Taiwan Strait During The 1997-1998 El Niño Winter, S. Shang, C. Zhang, H. Hong, Q. Liu, G. T. F. Wong, C. Hu, B. Huang

OES Faculty Publications

During the 1997–1998 El Niño event, the average sea surface temperature (SST) in the Taiwan Strait (TWS) in the winter was ~1.4°C higher than that of the winter climatological mean. The areal ratio of the warm water (≥2°C above the regional mean) to the cold water (≥2°C below the regional mean) in the TWS increased by 25% while the area of the eutrophic water (chlorophyll a >1 mg m-3) was halved. Field observations also indicate that the mixed layer in the TWS became more nutrient-poor during this winter. These observations are consistent with a diminished advection of the …

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Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder Jan 2005

Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder

Dissertations, Theses, and Masters Projects

No abstract provided.

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Shore-Oblique Bars, Nearshore Gravel Outcrops, And Their Correlation To Shoreline Change, Courtney A. Schupp Jan 2005

Shore-Oblique Bars, Nearshore Gravel Outcrops, And Their Correlation To Shoreline Change, Courtney A. Schupp

Dissertations, Theses, and Masters Projects

No abstract provided.

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Exploring The Persistence Of Sorted Bedforms On The Inner-Shelf Of Wrightsville Beach, North Carolina, Benjamin Gutierez, George Voulgaris, Robert Thieler Dec 2004

Exploring The Persistence Of Sorted Bedforms On The Inner-Shelf Of Wrightsville Beach, North Carolina, Benjamin Gutierez, George Voulgaris, Robert Thieler

George Voulgaris

Geological studies offshore of Wrightsville Beach, North Carolina reveal subtle large-scale regions of coarse sand with gravel and shell hash (widths between 100 and 200 m and negative relief of ∼1 m) that trend obliquely to the coast. It was previously suggested that these regions serve as conduits for sand exchange between the shoreface and inner shelf during storm-associated downwelling. Consequently they were classified as rippled scour depressions. More recently, the role of alongshore flows and self-organization as a result of inhibited settling of fine sand has been discussed. In this study, 45 days of near-bed current measurements were analyzed …

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Effect Of Channel Bifurcation On Residual Estuarine Circulation: Winyah Bay, South Carolina, Yong Kim, George Voulgaris Dec 2004

Effect Of Channel Bifurcation On Residual Estuarine Circulation: Winyah Bay, South Carolina, Yong Kim, George Voulgaris

George Voulgaris

The residual circulation pattern of Winyah Bay, the fourth largest estuary on the eastern coast of the US, is examined using stationary and shipborne current measurements during periods of low freshwater discharge. The estuary has a complex morphology with a single channel and narrow banks at the river entrance and the bay mouth, and a bifurcated channel system (main and western channels, respectively) in the middle part that appears to affect the residual circulation. Overall, the upper (single channel morphology) and middle (dual-channel morphology) parts of the estuary exhibit a baroclinic residual circulation. The presence of bifurcated channels in the …

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