Search

Dataset: Snail larvae in turbulence and waves, Dispersing marine larvae can alter their physical transport by swimming vertically or sinking in response to environmental signals. However, it remains unknown whether any signals could enable larvae to navigate over large scales. We tested whether flow-induced larval behaviors vary with adults' physical environments using congeneric snail larvae from the wavy continental shelf (Tritia trivittata) and from turbulent inlets (Tritia obsoleta). This dataset includes observations of larvae in turbulence, in rotating flows dominated by vorticity or strain rates, and in rectilinear wave oscillations. Larval and water motion were observed using near-infrared particle image velocimetry (IR PIV), and analyses identified threshold signals causing larvae to change their direction or magnitude of propulsive force. The two species reacted similarly to turbulence but differently to waves, and their transport patterns would diverge in wavy, offshore regions. Wave-induced behaviors provide evidence that larvae may detect waves as both motions and sounds useful in navigation. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/739790, NSF Division of Ocean Sciences (NSF OCE) OCE-1060622

Dataset: Snail larvae in turbulence and waves, Dispersing marine larvae can alter their physical transport by swimming vertically or sinking in response to environmental signals. However, it remains unknown whether any signals could enable larvae to navigate over large scales. We tested whether flow-induced larval behaviors vary with adults' physical environments using congeneric snail larvae from the wavy continental shelf (Tritia trivittata) and from turbulent inlets (Tritia obsoleta). This dataset includes observations of larvae in turbulence, in rotating flows dominated by vorticity or strain rates, and in rectilinear wave oscillations. Larval and water motion were observed using near-infrared particle image velocimetry (IR PIV), and analyses identified threshold signals causing larvae to change their direction or magnitude of propulsive force. The two species reacted similarly to turbulence but differently to waves, and their transport patterns would diverge in wavy, offshore regions. Wave-induced behaviors provide evidence that larvae may detect waves as both motions and sounds useful in navigation. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/739790, NSF Division of Ocean Sciences (NSF OCE) OCE-1060622

Dataset: Snail larvae in turbulence and waves, Dispersing marine larvae can alter their physical transport by swimming vertically or sinking in response to environmental signals. However, it remains unknown whether any signals could enable larvae to navigate over large scales. We tested whether flow-induced larval behaviors vary with adults' physical environments using congeneric snail larvae from the wavy continental shelf (Tritia trivittata) and from turbulent inlets (Tritia obsoleta). This dataset includes observations of larvae in turbulence, in rotating flows dominated by vorticity or strain rates, and in rectilinear wave oscillations. Larval and water motion were observed using near-infrared particle image velocimetry (IR PIV), and analyses identified threshold signals causing larvae to change their direction or magnitude of propulsive force. The two species reacted similarly to turbulence but differently to waves, and their transport patterns would diverge in wavy, offshore regions. Wave-induced behaviors provide evidence that larvae may detect waves as both motions and sounds useful in navigation. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/739790, NSF Division of Ocean Sciences (NSF OCE) OCE-1060622

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 9765-9773, doi:10.1029/2018GL078543., A REMUS 600 autonomous underwater vehicle was used to measure turbulent mixing within the far‐field Chesapeake Bay plume during the transition to upwelling. Prior to the onset of upwelling, the plume was mixed by a combination of energetic downwelling winds and bottom‐generated shear resulting in a two‐layer plume structure. Estimates of turbulent dissipation and buoyancy flux from a nose‐mounted microstructure system indicate that scalar exchange within the plume was patchy and transient, with direct wind mixing constrained to the near surface by stratification within the plume. Changing wind and tide conditions contributed to temporal variability. Following the separation of the upper plume from the coast, alongshore shear became a significant driver of mixing on the shoreward edge of the plume., NSF Grant Numbers: OCE‐1334231, OCE‐1745258, OCE‐1334398, 2019-03-23

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 9765-9773, doi:10.1029/2018GL078543., A REMUS 600 autonomous underwater vehicle was used to measure turbulent mixing within the far‐field Chesapeake Bay plume during the transition to upwelling. Prior to the onset of upwelling, the plume was mixed by a combination of energetic downwelling winds and bottom‐generated shear resulting in a two‐layer plume structure. Estimates of turbulent dissipation and buoyancy flux from a nose‐mounted microstructure system indicate that scalar exchange within the plume was patchy and transient, with direct wind mixing constrained to the near surface by stratification within the plume. Changing wind and tide conditions contributed to temporal variability. Following the separation of the upper plume from the coast, alongshore shear became a significant driver of mixing on the shoreward edge of the plume., NSF Grant Numbers: OCE‐1334231, OCE‐1745258, OCE‐1334398, 2019-03-23

Marine phytoplankton account for approximately half of global primary productivity, making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon, which can stimulate nutrient regeneration, primary production and upper ocean respiration via lytic infection and the ‘virus shunt’. Ultimately, this limits the trophic transfer of carbon and energy to both higher food webs and the deep ocean. Using imagery taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite, along with a suite of diagnostic lipid- and gene-based molecular biomarkers, in situ optical sensors and sediment traps, we show that Coccolithovirus infections of mesoscale (~100 km) Emiliania huxleyi blooms in the North Atlantic are coupled with particle aggregation, high zooplankton grazing and greater downward vertical fluxes of both particulate organic and particulate inorganic carbon from the upper mixed layer. Our analyses captured blooms in different phases of infection (early, late and post) and revealed the highest export flux in ‘early-infected blooms’ with sinking particles being disproportionately enriched with infected cells and subsequently remineralized at depth in the mesopelagic. Our findings reveal viral infection as a previously unrecognized ecosystem process enhancing biological pump efficiency.

Marine phytoplankton account for approximately half of global primary productivity, making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon, which can stimulate nutrient regeneration, primary production and upper ocean respiration via lytic infection and the ‘virus shunt’. Ultimately, this limits the trophic transfer of carbon and energy to both higher food webs and the deep ocean. Using imagery taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite, along with a suite of diagnostic lipid- and gene-based molecular biomarkers, in situ optical sensors and sediment traps, we show that Coccolithovirus infections of mesoscale (~100 km) Emiliania huxleyi blooms in the North Atlantic are coupled with particle aggregation, high zooplankton grazing and greater downward vertical fluxes of both particulate organic and particulate inorganic carbon from the upper mixed layer. Our analyses captured blooms in different phases of infection (early, late and post) and revealed the highest export flux in ‘early-infected blooms’ with sinking particles being disproportionately enriched with infected cells and subsequently remineralized at depth in the mesopelagic. Our findings reveal viral infection as a previously unrecognized ecosystem process enhancing biological pump efficiency.

Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 37 (2007): 1859-1877, doi:10.1175/jpo3088.1., A series of dye releases in the Hudson River estuary elucidated diapycnal mixing rates and temporal variability over tidal and fortnightly time scales. Dye was injected in the bottom boundary layer for each of four releases during different phases of the tide and of the spring–neap cycle. Diapycnal mixing occurs primarily through entrainment that is driven by shear production in the bottom boundary layer. On flood the dye extended vertically through the bottom mixed layer, and its concentration decreased abruptly near the base of the pycnocline, usually at a height corresponding to a velocity maximum. Boundary layer growth is consistent with a one-dimensional, stress-driven entrainment model. A model was developed for the vertical structure of the vertical eddy viscosity in the flood tide boundary layer that is proportional to u2*/N∞, where u* and N∞ are the bottom friction velocity and buoyancy frequency above the boundary layer. The model also predicts that the buoyancy flux averaged over the bottom boundary layer is equal to 0.06N∞u2* or, based on the structure of the boundary layer equal to 0.1NBLu2*, where NBL is the buoyancy frequency across the flood-tide boundary layer. Estimates of shear production and buoyancy flux indicate that the flux Richardson number in the flood-tide boundary layer is 0.1–0.18, consistent with the model indicating that the flux Richardson number is between 0.1 and 0.14. During ebb, the boundary layer was more stratified, and its vertical extent was not as sharply delineated as in the flood. During neap tide the rate of mixing during ebb was significantly weaker than on flood, owing to reduced bottom stress and stabilization by stratification. As tidal amplitude increased ebb mixing increased and more closely resembled the boundary layer entrainment process observed during the flood. Tidal straining modestly increased the entrainment rate during the flood, and it restratified the boundary layer and inhibited mixing during the ebb., The work was supported by the National Science Foundation Grant OCE00-95972 (W. Geyer, J. Lerczak), OCE00-99310 (R. Houghton), and OCE00-95913 (R. Chant, E. Hunter).

Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 37 (2007): 1859-1877, doi:10.1175/jpo3088.1., A series of dye releases in the Hudson River estuary elucidated diapycnal mixing rates and temporal variability over tidal and fortnightly time scales. Dye was injected in the bottom boundary layer for each of four releases during different phases of the tide and of the spring–neap cycle. Diapycnal mixing occurs primarily through entrainment that is driven by shear production in the bottom boundary layer. On flood the dye extended vertically through the bottom mixed layer, and its concentration decreased abruptly near the base of the pycnocline, usually at a height corresponding to a velocity maximum. Boundary layer growth is consistent with a one-dimensional, stress-driven entrainment model. A model was developed for the vertical structure of the vertical eddy viscosity in the flood tide boundary layer that is proportional to u2*/N∞, where u* and N∞ are the bottom friction velocity and buoyancy frequency above the boundary layer. The model also predicts that the buoyancy flux averaged over the bottom boundary layer is equal to 0.06N∞u2* or, based on the structure of the boundary layer equal to 0.1NBLu2*, where NBL is the buoyancy frequency across the flood-tide boundary layer. Estimates of shear production and buoyancy flux indicate that the flux Richardson number in the flood-tide boundary layer is 0.1–0.18, consistent with the model indicating that the flux Richardson number is between 0.1 and 0.14. During ebb, the boundary layer was more stratified, and its vertical extent was not as sharply delineated as in the flood. During neap tide the rate of mixing during ebb was significantly weaker than on flood, owing to reduced bottom stress and stabilization by stratification. As tidal amplitude increased ebb mixing increased and more closely resembled the boundary layer entrainment process observed during the flood. Tidal straining modestly increased the entrainment rate during the flood, and it restratified the boundary layer and inhibited mixing during the ebb., The work was supported by the National Science Foundation Grant OCE00-95972 (W. Geyer, J. Lerczak), OCE00-99310 (R. Houghton), and OCE00-95913 (R. Chant, E. Hunter).

Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 37 (2007): 1859-1877, doi:10.1175/jpo3088.1., A series of dye releases in the Hudson River estuary elucidated diapycnal mixing rates and temporal variability over tidal and fortnightly time scales. Dye was injected in the bottom boundary layer for each of four releases during different phases of the tide and of the spring–neap cycle. Diapycnal mixing occurs primarily through entrainment that is driven by shear production in the bottom boundary layer. On flood the dye extended vertically through the bottom mixed layer, and its concentration decreased abruptly near the base of the pycnocline, usually at a height corresponding to a velocity maximum. Boundary layer growth is consistent with a one-dimensional, stress-driven entrainment model. A model was developed for the vertical structure of the vertical eddy viscosity in the flood tide boundary layer that is proportional to u2*/N∞, where u* and N∞ are the bottom friction velocity and buoyancy frequency above the boundary layer. The model also predicts that the buoyancy flux averaged over the bottom boundary layer is equal to 0.06N∞u2* or, based on the structure of the boundary layer equal to 0.1NBLu2*, where NBL is the buoyancy frequency across the flood-tide boundary layer. Estimates of shear production and buoyancy flux indicate that the flux Richardson number in the flood-tide boundary layer is 0.1–0.18, consistent with the model indicating that the flux Richardson number is between 0.1 and 0.14. During ebb, the boundary layer was more stratified, and its vertical extent was not as sharply delineated as in the flood. During neap tide the rate of mixing during ebb was significantly weaker than on flood, owing to reduced bottom stress and stabilization by stratification. As tidal amplitude increased ebb mixing increased and more closely resembled the boundary layer entrainment process observed during the flood. Tidal straining modestly increased the entrainment rate during the flood, and it restratified the boundary layer and inhibited mixing during the ebb., The work was supported by the National Science Foundation Grant OCE00-95972 (W. Geyer, J. Lerczak), OCE00-99310 (R. Houghton), and OCE00-95913 (R. Chant, E. Hunter).