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Full-Text Articles in Life Sciences
Overcoming Restoration Paradigms: Value Of The Historical Record And Metapopulation Dynamics In Native Oyster Restoration, Rom Lipcius, Russell P. Burke, Danielle N. Mcculloch, Sebastian J. Schreiber, David M. Schulte, Rochelle D. Seitz, Jian Shen
Overcoming Restoration Paradigms: Value Of The Historical Record And Metapopulation Dynamics In Native Oyster Restoration, Rom Lipcius, Russell P. Burke, Danielle N. Mcculloch, Sebastian J. Schreiber, David M. Schulte, Rochelle D. Seitz, Jian Shen
VIMS Articles
Restoration strategies for native oyster populations rely on multiple sources of information, which often conflict due to time- and space-varying patterns in abundance and distribution. For instance, strategies based on population connectivity and disease resistance can differ, and extant and historical records of abundance and distribution are often at odds, such that the optimal strategy is unclear and valuable restoration sites may be excluded from consideration. This was the case for the Lynnhaven River subestuary of lower Chesapeake Bay, which was deemed unsuitable for Eastern Oyster (Crassostrea virginica) restoration based on physical conditions, disease challenge, and extant oyster …
Source-Age Dynamics Of Estuarine Particulate Organic Matter Using Fatty Acid Delta C-13 And Delta C-14 Composition, Ha Mcintosh, Ap Mcnichol, L Xu, Elizabeth A. Canuel
Source-Age Dynamics Of Estuarine Particulate Organic Matter Using Fatty Acid Delta C-13 And Delta C-14 Composition, Ha Mcintosh, Ap Mcnichol, L Xu, Elizabeth A. Canuel
VIMS Articles
This study used a multiproxy approach to elucidate the source and age composition of estuarine particulate organic matter (POM) using bulk stable isotopes (C-13(POC)), fatty acid (FA) biomarkers, and compound specific isotopic analyses in surface waters along the Delaware River and Bay (Delaware Estuary, hereafter). C-13 values of FA (C-13(FA)) ranged more widely (-30.9 parts per thousand to -21.8 parts per thousand) than C-13(POC) (-27.5 parts per thousand to -23.5 parts per thousand), providing greater insight about POM sources along the estuary. C-13 values of C-16:0 phospholipid FA (primarily, aquatic sources) increased along the salinity gradient (-29.8 parts per thousand …
Anthropogenic Controls On Overwash Deposition: Evidence And Consequences, Laura J. Rogers, Laura J. Moore, Evan B. Goldstein, Christopher J. Hein, Jorge Lorenzo-Trueba, Andrew D. Ashton
Anthropogenic Controls On Overwash Deposition: Evidence And Consequences, Laura J. Rogers, Laura J. Moore, Evan B. Goldstein, Christopher J. Hein, Jorge Lorenzo-Trueba, Andrew D. Ashton
VIMS Articles
Accelerated sea level rise and the potential for an increase in frequency of the most intense hurricanes due to climate change threaten the vitality and habitability of barrier islands by lowering their relative elevation and altering frequency of overwash. High-density development may further increase island vulnerability by restricting delivery of overwash to the subaerial island. We analyzed pre-Hurricane Sandy and post-Hurricane Sandy (2012) lidar surveys of the New Jersey coast to assess human influence on barrier overwash, comparing natural environments to two developed environments (commercial and residential) using shore-perpendicular topographic profiles. The volumes of overwash delivered to residential and commercial …
Phytoplankton Growth Rates In The Ross Sea, Antarctica, Anna F. Mosby, Walker O. Smith Jr.
Phytoplankton Growth Rates In The Ross Sea, Antarctica, Anna F. Mosby, Walker O. Smith Jr.
VIMS Articles
The Ross Sea is a highly productive region of the Southern Ocean, but phytoplankton growth rates there are poorly constrained. Variability in growth rates was investigated on a January February 2012 cruise to the Ross Sea using 37 C-14 isotopic tracer incubations and 11 dilution experiments. We examined the effects of extended incubations on measured growth rates in C-14 incubations, quantified phytoplankton growth and grazing mortality rates through dilution experiments, and analyzed the effects of irradiance on carbon:chlorophyll ratios in dilution experiments. Growth rates in C-14 incubations ranged from 0.03 to 0.85 d(-1). We found that chlorophyll-based phytoplankton growth rates …
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 …
Decoupling The Influence Of Biological And Physical Processes On The Dissolved Oxygen In The Chesapeake Bay, Jiabi Du, Jian Shen
Decoupling The Influence Of Biological And Physical Processes On The Dissolved Oxygen In The Chesapeake Bay, Jiabi Du, Jian Shen
VIMS Articles
It is instructive and essential to decouple the effects of biological and physical processes on the dissolved oxygen condition, in order to understand their contribution to the interannual variability of hypoxia in Chesapeake Bay since the 1980s. A conceptual bottom DO budget model is applied, using the vertical exchange time scale (VET) to quantify the physical condition and net oxygen consumption rate to quantify biological activities. By combining observed DO data and modeled VET values along the main stem of the Chesapeake Bay, the monthly net bottom DO consumption rate was estimated for 1985-2012. The DO budget model results show …
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 …
Use Of Esi-Fticr-Ms To Characterize Dissolved Organic Matter In Headwater Streams Draining Forest-Dominated And Pasture-Dominated Watersheds, Yuehan Lu, Xiaping Li, Rajaa Mesfioui, James E. Bauer, R M. Chambers, Elizabeth A. Canuel, Patrick Hatcher
Use Of Esi-Fticr-Ms To Characterize Dissolved Organic Matter In Headwater Streams Draining Forest-Dominated And Pasture-Dominated Watersheds, Yuehan Lu, Xiaping Li, Rajaa Mesfioui, James E. Bauer, R M. Chambers, Elizabeth A. Canuel, Patrick Hatcher
VIMS Articles
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proven to be a powerful technique revealing complexity and diversity of natural DOM molecules, but its application to DOM analysis in grazing-impacted agricultural systems remains scarce. In the present study, we presented a case study of using ESI-FTICR-MS in analyzing DOM from four headwater streams draining forest-or pasture-dominated watersheds in Virginia, USA. In all samples, most formulas were CHO compounds (71.8-87.9%), with other molecular series (CHOS, CHON, CHONS, and CHOP (N, S)) accounting for only minor fractions. All samples were dominated by molecules falling in the lignin-like region (H/C …
Event-To-Seasonal Sediment Dispersal On The Waipaoa River Shelf, New Zealand: A Numerical Modeling Study, Julia M. Moriarty, Courtney K. Harris, Mg Hadfield
Event-To-Seasonal Sediment Dispersal On The Waipaoa River Shelf, New Zealand: A Numerical Modeling Study, Julia M. Moriarty, Courtney K. Harris, Mg Hadfield
VIMS Articles
The formation of the geologic record offshore of small mountainous rivers is event-driven and, more so than many other environments, can result in relatively complete sequences. One such river, the Waipaoa in New Zealand, has been studied from its terrestrial source to its oceanic sink over timescales spanning storms, seasons, and the Holocene. This study focused on the formation of riverine deposits on the Waipaoa Shelf during episodic flood and wave events, contrasting deposition during short-lived events to accumulation patterns created over thirteen months. Sediment fluxes and fate were estimated using the numerical hydrodynamic and sediment transport model ROMS, the …
Sediment Transport-Based Metrics Of Wetland Stability, Nk Ganju, Matthew L. Kirwan, Pj Dickhudt, Gr Guntenspergen, Dr Cahoon, Kd Kroeger
Sediment Transport-Based Metrics Of Wetland Stability, Nk Ganju, Matthew L. Kirwan, Pj Dickhudt, Gr Guntenspergen, Dr Cahoon, Kd Kroeger
VIMS Articles
Despite the importance of sediment availability on wetland stability, vulnerability assessments seldom consider spatiotemporal variability of sediment transport. Models predict that the maximum rate of sea level rise a marsh can survive is proportional to suspended sediment concentration (SSC) and accretion. In contrast, we find that SSC and accretion are higher in an unstable marsh than in an adjacent stable marsh, suggesting that these metrics cannot describe wetland vulnerability. Therefore, we propose the flood/ebb SSC differential and organic-inorganic suspended sediment ratio as better vulnerability metrics. The unstable marsh favors sediment export (18mgL(-1) higher on ebb tides), while the stable marsh …
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 …