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Full-Text Articles in Animal Sciences
Phytoplankton-Bacterial Interactions Mediate Micronutrient Colimitation At The Coastal Antarctic Sea Ice Edge, Em Bertrand, Jp Mccrow, A Moustafa, H Zheng, Jb Mcquaid, Af Post, Rachel E. Sipler, Jl Spackeen, K Xu, Da Bronk, Da Hutchins, Ae Allen
Phytoplankton-Bacterial Interactions Mediate Micronutrient Colimitation At The Coastal Antarctic Sea Ice Edge, Em Bertrand, Jp Mccrow, A Moustafa, H Zheng, Jb Mcquaid, Af Post, Rachel E. Sipler, Jl Spackeen, K Xu, Da Bronk, Da Hutchins, Ae Allen
VIMS Articles
Southern Ocean primary productivity plays a key role in global ocean biogeochemistry and climate. At the Southern Ocean sea ice edge in coastal McMurdo Sound, we observed simultaneous cobalamin and iron limitation of surface water phytoplankton communities in late Austral summer. Cobalamin is produced only by bacteria and archaea, suggesting phytoplankton-bacterial interactions must play a role in this limitation. To characterize these interactions and investigate the molecular basis of multiple nutrient limitation, we examined transitions in global gene expression over short time scales, induced by shifts in micronutrient availability. Diatoms, the dominant primary producers, exhibited transcriptional patterns indicative of co-occurring …
Stable Isotopic And Biomarker Evidence Of Terrigenous Organic Matter Export To The Deep Sea During Tropical Storms, K Selvaraj, Ty Lee, Jyt Yang, Elizabeth A. Canuel, Jc Huang, Et Al.
Stable Isotopic And Biomarker Evidence Of Terrigenous Organic Matter Export To The Deep Sea During Tropical Storms, K Selvaraj, Ty Lee, Jyt Yang, Elizabeth A. Canuel, Jc Huang, Et Al.
VIMS Articles
The global export of organic carbon (OC) is intimately linked to the total flux of terrestrial sediment to the ocean, with the continental margins receiving similar to 90% of the sediment generated by erosion on land. Recent studies suggest that a substantial amount of particulate OC (POC) might escape from the shelf and be exported to the continental slope-deep sea sector, although the mechanisms and magnitude of such deep sea POC transfer remain unknown. Here we investigate hyperpycnal flow-associated total suspended matter (TSM) collected from water depths of similar to 3000 m, near the bottom of sea floor, in the …
Seasonality Of Biological And Physical Controls On Surface Ocean Co2 From Hourly Observations At The Southern Ocean Time Series Site South Of Australia, Eh Shadwick, Tw Trull, B Tilbrook, Aj Sutton, E Schulz, Et Al.
Seasonality Of Biological And Physical Controls On Surface Ocean Co2 From Hourly Observations At The Southern Ocean Time Series Site South Of Australia, Eh Shadwick, Tw Trull, B Tilbrook, Aj Sutton, E Schulz, Et Al.
VIMS Articles
The Subantarctic Zone (SAZ), which covers the northern half of the Southern Ocean between the Subtropical and Subantarctic Fronts, is important for air-sea CO2 exchange, ventilation of the lower thermocline, and nutrient supply for global ocean productivity. Here we present the first high-resolution autonomous observations of mixed layer CO2 partial pressure (pCO(2)) and hydrographic properties covering a full annual cycle in the SAZ. The amplitude of the seasonal cycle in pCO(2) (similar to 60 mu atm), from near-atmospheric equilibrium in late winter to similar to 330 mu atm in midsummer, results from opposing physical and biological drivers. Decomposing these contributions …
Image Processing Methods For In Situ Estimation Of Cohesive Sediment Floc Size, Settling Velocity, And Density, Sj Smith, Carl T. Friedrichs
Image Processing Methods For In Situ Estimation Of Cohesive Sediment Floc Size, Settling Velocity, And Density, Sj Smith, Carl T. Friedrichs
VIMS Articles
Recent advances in development of in situ video settling columns have significantly contributed toward fine-sediment dynamics research through concurrent measurement of suspended sediment floc size distributions and settling velocities, which together also allow inference of floc density. Along with image resolution and sizing, two additional challenges in video analysis from these devices are the automated tracking of settling particles and accounting for fluid motions within the settling column. A combination of particle tracking velocimetry (PTV) and particle image velocimetry (PIV) image analysis techniques is described, which permits general automation of image analysis collected from video settling columns. In the fixed …
Iron Supply And Demand In An Antarctic Shelf Ecosystem, Dj Mcgillicuddy, Pn Sedwick, Ms Dinniman, Kr Arrigo, Ts Bibby, Bjw Greenan, Ee Hofmann, Jm Klinck, Walker O. Smith Jr., Sl Mack, Cm Marsay, Bm Sohst, Gl Van Dijken
Iron Supply And Demand In An Antarctic Shelf Ecosystem, Dj Mcgillicuddy, Pn Sedwick, Ms Dinniman, Kr Arrigo, Ts Bibby, Bjw Greenan, Ee Hofmann, Jm Klinck, Walker O. Smith Jr., Sl Mack, Cm Marsay, Bm Sohst, Gl Van Dijken
VIMS Articles
The Ross Sea sustains a rich ecosystem and is the most productive sector of the Southern Ocean. Most of this production occurs within a polynya during the November-February period, when the availability of dissolved iron (dFe) is thought to exert the major control on phytoplankton growth. Here we combine new data on the distribution of dFe, high-resolution model simulations of ice melt and regional circulation, and satellite-based estimates of primary production to quantify iron supply and demand over the Ross Sea continental shelf. Our analysis suggests that the largest sources of dFe to the euphotic zone are wintertime mixing and …
In Situ Phytoplankton Distributions In The Amundsen Sea Polynya Measured By Autonomous Gliders, O Schofield, T Miles, Ac Alderkamp, S Lee, C Haskins, E Rogalsky, Rachel E. Sipler, Rm Sherrell, Pl Yager
In Situ Phytoplankton Distributions In The Amundsen Sea Polynya Measured By Autonomous Gliders, O Schofield, T Miles, Ac Alderkamp, S Lee, C Haskins, E Rogalsky, Rachel E. Sipler, Rm Sherrell, Pl Yager
VIMS Articles
The Amundsen Sea Polynya is characterized by large phytoplankton blooms, which makes this region disproportionately important relative to its size for the biogeochemistry of the Southern Ocean. In situ data on phytoplankton are limited, which is problematic given recent reports of sustained change in the Amundsen Sea. During two field expeditions to the Amundsen Sea during austral summer 2010-2011 and 2014, we collected physical and bio-optical data from ships and autonomous underwater gliders. Gliders documented large phytoplankton blooms associated with Antarctic Surface Waters with low salinity surface water and shallow upper mixed layers (< 50 m). High biomass was not always associated with a specific water mass, suggesting the importance of upper mixed depth and light in influencing phytoplankton biomass. Spectral optical backscatter and ship pigment data suggested that the composition of phytoplankton was spatially heterogeneous, with the large blooms dominated by Phaeocystis and non-bloom waters dominated by diatoms. Phytoplankton growth rates estimated from field data (< = 0.10 day(-1)) were at the lower end of the range measured during ship-based incubations, reflecting both in situ nutrient and light limitations. In the bloom waters, phytoplankton biomass was high throughout the 50-m thick upper mixed layer. Those biomass levels, along with the presence of colored dissolved organic matter and detritus, resulted in a euphotic zone that was often < 10 m deep. The net result was that the majority of phytoplankton were light-limited, suggesting that mixing rates within the upper mixed layer were critical to determining the overall productivity; however, regional productivity will ultimately be controlled by water column stability and the depth of the upper mixed layer, which may be enhanced with continued ice melt in the Amundsen Sea Polynya.
Bioavailability Of Surface Dissolved Organic Matter To Aphotic Bacterial Communities In The Amundsen Sea Polynya, Antarctica, Rachel E. Sipler, Tl Connelly
Bioavailability Of Surface Dissolved Organic Matter To Aphotic Bacterial Communities In The Amundsen Sea Polynya, Antarctica, Rachel E. Sipler, Tl Connelly
VIMS Articles
Antarctic seas, and particularly the Amundsen Sea Polynya, are some of the most productive oceanic regions on Earth. Ice-algal production during austral spring is followed by open-water pelagic production later in the season. Although ice-free growth accounts for a greater percentage of the annual net primary production, ice algae provide an important source of nutrients to organisms throughout the water column and benthos in areas and seasons when open-water production is insignificant. The objectives of this study were to assess the bioavailability of dissolved organic matter (DOM), sourced from ice algae or the chlorophyll maximum (chl max), to marine bacterioplankton …
Characterizing The Natural System: Toward Sustained, Integrated Coastal Ocean Acidification Observing Networks To Facilitate Resource Management And Decision Support, Sr Alin, Re Brainard, Nn Price, Ja Newton, A Cohen, Eh Decarlo, Eh Shadwick, Et Al
Characterizing The Natural System: Toward Sustained, Integrated Coastal Ocean Acidification Observing Networks To Facilitate Resource Management And Decision Support, Sr Alin, Re Brainard, Nn Price, Ja Newton, A Cohen, Eh Decarlo, Eh Shadwick, Et Al
VIMS Articles
Coastal ocean ecosystems have always served human populations they provide food security, livelihoods, coastal protection, and defense. Ocean acidification is a global threat to these ecosystem services, particularly when other local and regional stressors combine with it to jeopardize coastal health. Monitoring efforts call for a coordinated global approach toward sustained, integrated coastal ocean health observing networks to address the region-specific mix of factors while also adhering to global ocean acidification observing network principles to facilitate comparison among regions for increased utility and understanding. Here, we generalize guidelines for scoping and designing regional coastal ocean acidification observing networks and provide …
Habitat Context Influences Nitrogen Removal By Restored Oyster Reefs, Ar Smyth, Mf Piehler, Jh Grabowski
Habitat Context Influences Nitrogen Removal By Restored Oyster Reefs, Ar Smyth, Mf Piehler, Jh Grabowski
VIMS Articles
Like many ecosystem functions in marine and terrestrial environments, nutrient processing varies dramatically over small spatial scales, making efforts to apply findings within and across ecosystems challenging. In estuaries, information on the influence of habitat context on sediment nutrient cycling is lacking even though this is an important estuarine function with high societal value. We collected triplicate intact sediment cores from restored oyster reefs located in different habitat contexts (adjacent to salt marshes, seagrass beds and mudflats), as well as salt marshes, seagrass beds and mudflats without reefs (controls). Sediment denitrification and fluxes of dissolved inorganic nitrogen were measured under …
Coastal Response To Late-Stage Transgression And Sea-Level Highstand, C J. Hein, Dm Fitzgerald, Jt De Menezes, Wj Cleary, Ahf Klein
Coastal Response To Late-Stage Transgression And Sea-Level Highstand, C J. Hein, Dm Fitzgerald, Jt De Menezes, Wj Cleary, Ahf Klein
VIMS Articles
Coastal morphologic features associated with past shoreline transgressions and sea-level highstands can provide insight into the rates and processes associated with coastal response to the modern global rise in sea level. Along the eastern and southern Brazilian coasts of South America, 6000 years of sea-level fall have preserved late-stage transgressive and sea-level highstand features 1-4 m above present mean sea level and several kilometers landward of modern shorelines. GPS with real-time kinematics data, ground-penetrating radar, stratigraphy, and radiocarbon dating within a 2-3-km-wide river-associated strandplain in central Santa Catarina (southern Brazil) uncovered a diverse set of late-stage transgressive and highstand deposits. …
Ocean Processes At The Antarctic Continental Slope, Kj Heywood, S Schmidtko, C Heuze, J Kaiser, Td Jickells, Walker O. Smith, Et Al.
Ocean Processes At The Antarctic Continental Slope, Kj Heywood, S Schmidtko, C Heuze, J Kaiser, Td Jickells, Walker O. Smith, Et Al.
VIMS Articles
The Antarctic continental shelves and slopes occupy relatively small areas, but, nevertheless, are important for global climate, biogeochemical cycling and ecosystem functioning. Processes of water mass transformation through sea ice formation/melting and ocean-atmosphere interaction are key to the formation of deep and bottom waters as well as determining the heat flux beneath ice shelves. Climate models, however, struggle to capture these physical processes and are unable to reproduce water mass properties of the region. Dynamics at the continental slope are key for correctly modelling climate, yet their small spatial scale presents challenges both for ocean modelling and for observational studies. …
Effect Of Temperature On Rates Of Ammonium Uptake And Nitrification In The Western Coastal Arctic During Winter, Spring, And Summer, Se Baer, Tl Connelly, Rachel E. Sipler, Pl Yager, Da Bronk
Effect Of Temperature On Rates Of Ammonium Uptake And Nitrification In The Western Coastal Arctic During Winter, Spring, And Summer, Se Baer, Tl Connelly, Rachel E. Sipler, Pl Yager, Da Bronk
VIMS Articles
Biogeochemical rate processes in the Arctic are not currently well constrained, and there is very limited information on how rates may change as the region warms. Here we present data on the sensitivity of ammonium (NH4+) uptake and nitrification rates to short-term warming. Samples were collected from the Chukchi Sea off the coast of Barrow, Alaska, during winter, spring, and summer and incubated for 24h in the dark with additions of (NH4+)-N-15 at -1.5, 6, 13, and 20 degrees C. Rates of NH4+ uptake and nitrification were measured in conjunction with bacterial production. In all seasons, NH4+ uptake rates were …
Earth Is (Mostly) Flat: Apportionment Of The Flux Of Continental Sediment Over Millennial Time Scales Comment, Ja Warrick, Jd Milliman, De Walling, Rj Wasson, Jpm Syvitski, Re Aalto
Earth Is (Mostly) Flat: Apportionment Of The Flux Of Continental Sediment Over Millennial Time Scales Comment, Ja Warrick, Jd Milliman, De Walling, Rj Wasson, Jpm Syvitski, Re Aalto
VIMS Articles
No abstract provided.
Inner-Shelf Circulation And Sediment Dynamics On A Series Of Shoreface-Connected Ridges Offshore Of Fire Island, Ny, Jc Warner, Jh List, Wc Schwab, G Voulgaris, B Armstrong, N Marshall
Inner-Shelf Circulation And Sediment Dynamics On A Series Of Shoreface-Connected Ridges Offshore Of Fire Island, Ny, Jc Warner, Jh List, Wc Schwab, G Voulgaris, B Armstrong, N Marshall
VIMS Articles
Locations along the inner-continental shelf offshore of Fire Island, NY, are characterized by a series of shoreface-connected ridges (SFCRs). These sand ridges have approximate dimensions of 10 km in length, 3 km spacing, and up to similar to 8 m ridge to trough relief and are oriented obliquely at approximately 30 degrees clockwise from the coastline. Stability analysis from previous studies explains how sand ridges such as these could be formed and maintained by storm-driven flows directed alongshore with a key maintenance mechanism of offshore deflected flows over ridge crests and onshore in the troughs. We examine these processes both …
Urea Uptake And Carbon Fixation By Marine Pelagic Bacteria And Archaea During The Arctic Summer And Winter Seasons, Tl Connelly, Se Baer, Jt Cooper, Da Bronk, B Wawrik
Urea Uptake And Carbon Fixation By Marine Pelagic Bacteria And Archaea During The Arctic Summer And Winter Seasons, Tl Connelly, Se Baer, Jt Cooper, Da Bronk, B Wawrik
VIMS Articles
How Arctic climate change might translate into alterations of biogeochemical cycles of carbon (C) and nitrogen (N) with respect to inorganic and organic N utilization is not well understood. This study combined N-15 uptake rate measurements for ammonium, nitrate, and urea with N-15-and C-13-based DNA stable-isotope probing (SIP). The objective was to identify active bacterial and archeal plankton and their role in N and C uptake during the Arctic summer and winter seasons. We hypothesized that bacteria and archaea would successfully compete for nitrate and urea during the Arctic winter but not during the summer, when phytoplankton dominate the uptake …
The Effects Of Changing Winds And Temperatures On The Oceanography Of The Ross Sea In The 21st Century, Walker O. Smith, Ms Dinniman, Ee Hofmann, Jm Klinck
The Effects Of Changing Winds And Temperatures On The Oceanography Of The Ross Sea In The 21st Century, Walker O. Smith, Ms Dinniman, Ee Hofmann, Jm Klinck
VIMS Articles
The Ross Sea is critically important in regulating Antarctic sea ice and is biologically productive, which makes changes in the region's physical environment of global concern. We examined the effects of projected changes in atmospheric temperatures and winds on aspects of the ocean circulation likely important to primary production using a high-resolution sea ice-ocean-ice shelf model of the Ross Sea. The modeled summer sea-ice concentrations decreased by 56% by 2050 and 78% by 2100. The duration of shallow mixed layers over the continental shelf increased by 8.5 and 19.2days in 2050 and 2100, and the mean summer mixed layer depths …
Using Timescales To Interpret Dissolved Oxygen Distributions In The Bottom Waters Of Chesapeake Bay, Jian Shen, B Hong, Ay Kuo
Using Timescales To Interpret Dissolved Oxygen Distributions In The Bottom Waters Of Chesapeake Bay, Jian Shen, B Hong, Ay Kuo
VIMS Articles
A simplified conceptual model based on timescales of gravitational circulation, vertical exchange, and total oxygen consumption rate of the biochemical processes is presented to provide insight into the relationships between estuarine dynamics and bottom water dissolved oxygen (DO). Two dimensionless parameters are introduced to diagnose the relationship between the vertical exchange process and the biochemical DO consumption and the influence of gravitational circulation on replenishment of bottom DO. The relative magnitudes of these timescales provide a linkage between the physical and biochemical processes. The hypoxic and anoxic conditions in deep waters of Chesapeake Bay are successfully interpreted with these three …
Improved Method For Quantifying The Air-Sea Flux Of Volatile And Semi-Volatile Organic Carbon, Ej Hauser, Rm Dickhut, R Falconer, As Wozniak
Improved Method For Quantifying The Air-Sea Flux Of Volatile And Semi-Volatile Organic Carbon, Ej Hauser, Rm Dickhut, R Falconer, As Wozniak
VIMS Articles
A method for quantifying the diffusive air-sea exchange of gaseous organic carbon (OC) was developed. OC compounds were separated into two operational pools-those that were kinetically air limited in diffusion across the air-sea interface and those that were water limited-during simultaneous air/water sampling. The method separates OC compounds into low Henry's law constant (low-H) semivolatile OC (SOC) and high Henry's law constant (high-H) volatile OC (VOC) pools that can be categorized by relating diffusion kinetic parameters to Henry's Law constant. Air limited (low-H; H << similar to 0.1 L atm mol(-1)) compounds were collected in pure water traps and were quantified as dissolved OC, whereas water limited (high-H; H >> similar to 0.1 L atm mol-1) compounds were collected on solid sorbent tubes downstream from the …
Spatial, Temporal, And Human-Induced Variations In Suspended Sediment Concentration In The Surface Waters Of The Yangtze Estuary And Adjacent Coastal Areas, P Li, Sl Yang, Jd Milliman, Kh Xu, Wh Qin, Et Al.
Spatial, Temporal, And Human-Induced Variations In Suspended Sediment Concentration In The Surface Waters Of The Yangtze Estuary And Adjacent Coastal Areas, P Li, Sl Yang, Jd Milliman, Kh Xu, Wh Qin, Et Al.
VIMS Articles
To delineate temporal and spatial variations in suspended sediment concentration (SSC) in the Yangtze (Changjiang) Estuary and adjacent coastal waters, surface-water samples were taken twice daily from 10 stations over periods ranging from 2 to 12 years (total number of samples > 28,000). Synoptic measurements in 2009 showed an increase in surface SSC from 0.058 g/l in the upper sections of the estuary to similar to 0.6 g/l at the Yangtze River turbidity maximum at the river mouth, decreasing seaward to 0.057 g/l. Annual periodicities reflect variations in the Yangtze discharge, which affect the horizontal distribution and transport of SSC, and …
A Modeling Study On The Response Of Chesapeake Bay To Hurricane Events Of Floyd And Isabel, Kh Cho, Harry V. Wang, Jian Shen, A Valle-Levinson, Yc Teng
A Modeling Study On The Response Of Chesapeake Bay To Hurricane Events Of Floyd And Isabel, Kh Cho, Harry V. Wang, Jian Shen, A Valle-Levinson, Yc Teng
VIMS Articles
The response of Chesapeake Bay to forcing from two hurricanes is investigated using an unstructured-grid three-dimensional hydrodynamic model SELFE. The model domain includes Chesapeake Bay, its tributaries, and the extended continental shelf in the mid-Atlantic Bight. The hurricanes chosen for the study are Hurricane Floyd (1999) and Hurricane Isabel (2003), both of which made landfall within 100 km of the mouth of the Bay. The model results agree reasonably well with field observations of water level, velocity, and salinity. From the Bay's water level response to the hurricanes, it was found that the storm surge in the Bay has two …
Relative Role Of Wind Forcing And Riverine Nutrient Input On The Extent Of Hypoxia In The Northern Gulf Of Mexico, Y Feng, Sf Dimarco, Ga Jackson
Relative Role Of Wind Forcing And Riverine Nutrient Input On The Extent Of Hypoxia In The Northern Gulf Of Mexico, Y Feng, Sf Dimarco, Ga Jackson
VIMS Articles
Seasonal hypoxia of the northern Gulf of Mexico has been observed for more than 25 years. It is generally accepted that the variation in the areal extent of hypoxia is determined by changes in nutrient addition from the Mississippi River. In this study, we investigate the statistical relation between the hypoxic area and a new variable, the duration of west wind, using the available measurements for the period 1985-2010. Special consideration was paid to the 1993-2010 period, a time when a large shift in the seasonal hypoxia pattern has been reported. When excluding the years in which hurricanes directly impacted …
Assimilatory Nitrate Utilization By Bacteria On The West Florida Shelf As Determined By Stable Isotope Probing And Functional Microarray Analysis, B Wawrik, Wb Boling, Jd Van Nostrand, Jp Xie, Jz Zhou, Da Bronk
Assimilatory Nitrate Utilization By Bacteria On The West Florida Shelf As Determined By Stable Isotope Probing And Functional Microarray Analysis, B Wawrik, Wb Boling, Jd Van Nostrand, Jp Xie, Jz Zhou, Da Bronk
VIMS Articles
Dissolved inorganic nitrogen (DIN) uptake by marine heterotrophic bacteria has important implications for the global nitrogen (N) and carbon (C) cycles. Bacterial nitrate utilization is more prevalent in the marine environment than traditionally thought, but the taxonomic identity of bacteria that utilize nitrate is difficult to determine using traditional methodologies. 15N-based DNA stable isotope probing was applied to document direct use of nitrate by heterotrophic bacteria on the West Florida Shelf. Seawater was incubated in the presence of 2 mu M 15N ammonium or 15N nitrate. DNA was extracted, fractionated via CsCl ultracentrifugation, and each fraction was analyzed by terminal …
Fossil And Contemporary Aerosol Particulate Organic Carbon In The Eastern United States: Implications For Deposition And Inputs To Watersheds, As Wozniak, Je Bauer, Rm Dickhut
Fossil And Contemporary Aerosol Particulate Organic Carbon In The Eastern United States: Implications For Deposition And Inputs To Watersheds, As Wozniak, Je Bauer, Rm Dickhut
VIMS Articles
Atmospheric particulate matter samples were collected from mid-Atlantic and northeastern U. S. (Virginia and New York, respectively) sites to assess the fossil versus contemporary sources contributing to aerosol organic carbon (OC) and the implications for its deposition to watersheds. Mean particulate matter total OC (TOC) deposition rates (wet + dry deposition) were calculated to be 1.6 and 2.4 mg C m(-2) d(-1) for the Virginia and New York sites, respectively. Wet deposition of particulate TOC was determined to be the dominant depositional mode, accounting for >65% (Virginia) and >80% (New York) of total aerosol TOC deposition. Isotopic mass balances suggest …
Carbon And Nitrogen Dynamics In Shallow Photic Systems: Interactions Between Macroalgae, Microalgae, And Bacteria, Ak Hardison, Iris C. Anderson, Elizabeth A. Canuel, Cr Tobias, B Veuger
Carbon And Nitrogen Dynamics In Shallow Photic Systems: Interactions Between Macroalgae, Microalgae, And Bacteria, Ak Hardison, Iris C. Anderson, Elizabeth A. Canuel, Cr Tobias, B Veuger
VIMS Articles
We tracked carbon (C) and nitrogen (N) uptake into sediments in the presence and absence of benthic macroalgae using dual stable isotope tracers in combination with compound-specific isotope analyses of hydrolyzable amino acids and phospholipid-linked fatty acids to quantify the uptake and retention of C and N within bulk sediments, benthic microalgae (BMA), and heterotrophic bacteria. Stable isotope tracers (as (15)NH(4)(+) and H(13)CO(3)(-)) were added to mesocosms either via the surface water or pore water for the first 14 d of the 42-d experiment. Macroalgae and sediments exposed to ambient light and dark cycles rapidly took up label from both …
Effluent Organic Nitrogen (Eon): Bioavailability And Photochemical And Salinity-Mediated Release, Da Bronk, Qn Roberts, Mp Sanderson, Ea Canuel, Pg Hatcher, Et Al.
Effluent Organic Nitrogen (Eon): Bioavailability And Photochemical And Salinity-Mediated Release, Da Bronk, Qn Roberts, Mp Sanderson, Ea Canuel, Pg Hatcher, Et Al.
VIMS Articles
The goal of this study was to investigate three potential ways that the soluble organic nitrogen (N) fraction of wastewater treatment plant (WWTP) effluents, termed effluent organic N (EON), could contribute to coastal eutrophication - direct biological removal, photochemical release of labile compounds, and salinity-mediated release of ammonium (NH4+). Effluents from two WWTPs were used in the experiments. For the bioassays, EON was added to water from four salinities (similar to 0 to 30) collected from the James River (VA) in August 2008, and then concentrations of N and phosphorus compounds were measured periodically over 48 h. Bioassay results, based …
Ocean Urea Fertilization For Carbon Credits Poses High Ecological Risks, Pm Glibert, R Azanza, M Burford, K Furuya, E Abal, D. A. Bronk, Et Al.
Ocean Urea Fertilization For Carbon Credits Poses High Ecological Risks, Pm Glibert, R Azanza, M Burford, K Furuya, E Abal, D. A. Bronk, Et Al.
VIMS Articles
The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many …
Quantifying Benthic Exchange Of Fine Sediment Via Continuous, Noninvasive Measurements Of Settling Velocity And Bed Erodibility, Carl T. Friedrichs, Grace M. Cartright, Pj Dickhudt
Quantifying Benthic Exchange Of Fine Sediment Via Continuous, Noninvasive Measurements Of Settling Velocity And Bed Erodibility, Carl T. Friedrichs, Grace M. Cartright, Pj Dickhudt
VIMS Articles
No abstract provided.
Melting Glaciers: A Probable Source Of Ddt To The Antarctic Marine Ecosystem, Hn Geisz, Rm Dickhut, Ma Cochran, Wr Fraser, Hw Ducklow
Melting Glaciers: A Probable Source Of Ddt To The Antarctic Marine Ecosystem, Hn Geisz, Rm Dickhut, Ma Cochran, Wr Fraser, Hw Ducklow
VIMS Articles
Persistent organic pollutants reach polar regions by long-range atmospheric transport and biomagnify through the food web accumulating in higher trophic level predators. We analyzed Adelie penguin (Pygoscelis adeliae) samples collected from 2004 to 2006 to evaluate current levels of Sigma DDT (p,p'-DDT + p,p'-DDE) in these birds, which are confined to Antarctica. Ratios of p,p'-DDT to p,p'-DDE in Adelie penguins have declined significantly since 1964 indicating current exposure to old rather than new sources of Sigma DDT. However, Sigma DDT has not declined in Adelie penguins from the Western Antarctic Peninsula for more than 30 years and the presence of …
Release Of Biodegradable Dissolved Organic Matter From Ancient Sedimentary Rocks, S Schillawski, S Petsch
Release Of Biodegradable Dissolved Organic Matter From Ancient Sedimentary Rocks, S Schillawski, S Petsch
VIMS Articles
Sedimentary rocks contain the largest mass of organic carbon on Earth, yet these reservoirs are not well integrated into modern carbon budgets. Here we describe the release of dissolved organic matter (DOM) from OM-rich sedimentary rocks under simulated weathering conditions. Results from column experiments demonstrate slow, sustained release of DOM from ancient sedimentary rocks under simulated weathering conditions. (1)H-NMR analysis of shale-derived DOM reveals a highly aliphatic, carbohydrate-poor material distinct from other natural DOM pools. Shale-derived DOM is rapidly assimilated and biodegraded by aerobic heterotrophic bacteria. Consequently, no compositional signature of shale-derived DOM other than (14)C-depletion is likely to persist …
What Exactly Are You Inferring? A Closer Look At Hypothesis Testing, Mc Newman
What Exactly Are You Inferring? A Closer Look At Hypothesis Testing, Mc Newman
VIMS Articles
This critical review describes the confused application of significance tests in environmental toxicology and chemistry that often produces incorrect inferences and indefensible regulatory decisions. Following a brief review of statistical testing theory, nine recommendations are put forward. The first is that confidence intervals be used instead of hypothesis tests whenever possible. The remaining recommendations are relevant if hypothesis tests are used. They are as follows: Define and justify Type I and II error rates a priori; set and justify an effect size a priori; do not confuse p(E vertical bar H-0) and p(H-0 vertical bar E); design tests permitting Positive …