A5062742041- Oceanographic and Atmospheric Processes
- Coastal and Marine Dynamics
- Coastal wetland ecosystem dynamics
- Tropical and Extratropical Cyclones Research
- Geological formations and processes
- Ocean Waves and Remote Sensing
- Coral and Marine Ecosystems Studies
- Marine and coastal ecosystems
- Marine and fisheries research
- Marine and coastal plant biology
- Hydrology and Sediment Transport Processes
- Geology and Paleoclimatology Research
- Fluid Dynamics and Turbulent Flows
- Marine Biology and Ecology Research
- Meteorological Phenomena and Simulations
- Fish Ecology and Management Studies
- Aeolian processes and effects
- Ocean Acidification Effects and Responses
- Marine Bivalve and Aquaculture Studies
- Underwater Acoustics Research
- Climate variability and models
- Wind and Air Flow Studies
- Hydrology and Watershed Management Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Aquatic Invertebrate Ecology and Behavior
Stanford University
2016-2025
Mechanics' Institute
2014-2024
Monterey Bay Aquarium Research Institute
2023-2024
The University of Queensland
2024
University of Bologna
2024
Palau International Coral Reef Center
2024
University of California, San Diego
2018
Irvine University
2018
University of California, Irvine
2018
Palo Alto University
2018
Applications of transport time scales are pervasive in biological, hydrologic, and geochemical studies yet these times not consistently defined applied with rigor the literature. We compare three (flushing time, age, residence time) commonly used to measure retention water or scalar quantities transported water. identify underlying assumptions associated each scale, describe procedures for computing idealized cases, pitfalls when real‐world systems deviate from idealizations. then apply...
Populations of native and introduced aquatic organisms in the San Francisco Bay/Sacramento‐San Joaquin Delta Estuary ("Bay/Delta") have undergone significant declines over past two decades. Decreased river inflow due to drought increased freshwater diversion contributed decline at least some populations. Effective management estuary's biological resources requires a sensitive indicator response that has ecological significance, can be measured accurately easily, could used as "policy"...
The geometric complexity of coral reefs leads to interesting fluid mechanics problems at scales ranging from those colonies or even branches a few millimeters in diameter up whole that can be kilometers horizontal extent. In many cases, both the colony and reef scale, unsteady flows, usually due surface waves, behave very differently than do steady flows for which structures may appear have quite high resistance any flow through their interior. Allowing this difference, engineering formulae...
A 2 week field experiment was conducted to measure surface wave dissipation on a barrier reef at Kaneohe Bay, Oahu, Hawaii. Wave heights and velocities were measured several locations the fore flat, which used estimate rates of by breaking bottom friction. Dissipation flat found be dominated friction that are significantly larger than those typically observed sandy beach sites. This is attributed rough generated organisms, makes highly efficient dissipating energy Results compared spectral...
The structure of the salinity field in northern San Francisco Bay and how it is affected by freshwater flow are discussed. Two datasets examined: first 23 years daily data taken U.S. Bureau Reclamation along axis Bay; second a set transects Geological Survey between 1988 1993. Central to this paper measure intrusion, X2: distance from Golden Gate Bridge where bottom 2 psu. Using X2 scale distance, authors find that for most conditions, mean distribution estuary nearly self-similar with...
Many benthic organisms form very rough surfaces on the seafloor that can be described as submerged canopies. Recent evidence has shown that, compared with a unidirectional current, an oscillatory flow driven by surface waves significantly enhance biological processes such nutrient uptake. However, to date, physical mechanisms responsible for this enhancement have not been established. This paper presents theoretical model estimate inside canopy flow. To reduce complexity of natural canopies,...
In this paper we present a method for measuring profiles of turbulence quantities using broadband acoustic doppler current profiler (ADCP). The follows previous work on the continental shelf and extends analysis to develop estimates errors associated with estimation methods. ADCP data was collected in an unstratified channel results are compared theory. This comparison shows that provides estimate Reynolds stresses, which is unbiased by Doppler noise, turbulent kinetic energy (TKE) biased...
We present observations of the diurnal formation horizontal temperature gradients in surface waters a sidearm small water supply reservoir at time during summer when radiative heating and vertical stratification reservoir’s were both quite strong. Our measurements show that because closed end was relatively shallow, daytime nighttime cooling created larger changes there than body lake, resulting large drove strongly sheared, exchanges. Because more vigorous turbulent mixing cooling,...
The authors present a field study of estuarine turbulence in which profiles Reynolds stresses were directly measured using an ADCP throughout 25-h tidal day. dataset that is discussed quantifies turbulent mixing for water column northern San Francisco Bay experiences sequence states includes weak ebb and flood are stratified, followed by strong, eventually unstratified, flood. These measurements show energetic confined to bottom mixed layer the overlying stratification. Examination...
We examined the role of wave‐driven circulation relative to wind and buoyancy forcing in a coral reef‐lagoon system. Circulation measurements Paopao Bay, Moorea, French Polynesia, during austral summer show importance waves driving flows over reef crest, through lagoon, out pass. Tides were comparatively weak, due proximity amphidromic points, exhibited an unusual spring‐neap cycle where major lunar tide modulated solar tide, overall tidal phase stayed approximately constant. Wind had only...
The creation of residual flows in estuaries is examined using acoustic Doppler current profiler data sets from northern San Francisco Bay. are analyzed principal component analysis to examine the temporal variability which create circulation. It seen that this periodically and partially stratified estuary created through a series pulses with strong at 24‐hour timescale, interaction shear, stratification mixing. This captured use dimensionless number, horizontal Richardson number ( Ri x ),...
Abstract The response of the circulation a coral reef system in Kaneohe Bay, Hawaii, to incident wave forcing was investigated using field data collected during 10-month experiment. Results from study revealed that dominant mechanism driving over much Bay. As predicted theoretically, setup generated near crest resulting breaking established pressure gradient drove flow and out two channels. Maximum found be roughly proportional offshore energy flux above threshold root-mean-square height 0.7...
Measurements of velocity and rates turbulence were made across a fringing coral reef in the Gulf Aqaba, Red Sea, to determine effect that rough topography has on boundary layer mixing flow dynamics. Observations at two fore-reef sites nearby sandy slope. The friction velocity, u*, drag coefficient, CD, determined directly from turbulent Reynolds stresses measured using acoustic Doppler velocimeters. Values CD for substrates ranged 0.009 0.015, three five times greater than over bottom site....
We present findings from two sets of measurements that quantified currents around and over the full extent a giant kelp ( Macrocystis pyrifera ) forest located at Mohawk Reef, Santa Barbara, California. Velocities were damped inside this 200‐m X 300‐m forest, but not to reported for larger (kilometer‐scale) beds, suggesting alongshore may play greater role in exchange than has often been assumed. Secondary flow features bear on performance organisms observed, including region along forest’s...
An experimental study of the dynamic response non-rotating, stratified reservoirs to application surface shear stresses is presented. The experiments were made using two-layered and linear stratifications; a moving belt was used supply stress fluid. Detailed measurements density field show that upwelling occurs at all values Wedderburn number, W, rather than only occurring when W < 1. Differences between two-layer theory present observations are attributed fact stratifications continuous,...
A coupled wave‐circulation numerical model was used to simulate the distribution of wave energy, as well circulation induced by breaking, wind, and tidal forcing, within a coral reef system in Kaneohe Bay, Oahu, Hawaii. Modeled wave, current, setup fields were compared with field measurements collected on forereef, flat, channels lagoon over 4‐week period. The predicted height transformation across reef‐lagoon good agreement observations, using single‐parameter (spatially uniform) values...
Ocean acidification poses multiple challenges for coral reefs on molecular to ecological scales, yet previous experimental studies of the impact projected CO₂ concentrations have mostly been done in aquarium systems with corals removed from their natural ecosystem and placed under artificial light seawater conditions. The Coral-Proto Free Carbon Enrichment System (CP-FOCE) uses a network sensors monitor conditions within each flume maintain pH as an offset environmental using feedback...
Abstract We present a week of observations wave dissipation on the south forereef Palmyra Atoll. Using measurements made in 6.2 m and 11.2 water offshore surf zone, we computed energy fluxes near‐bottom velocity. Equating divergence shoreward flux to its by bottom friction parameterizating terms root‐mean‐square velocity cubed, find that factor, f w , for this reef is 1.80 ± 0.07, nearly an order magnitude larger than values previously found reefs. attribute remarkably high value complex...
Abstract Observations of waves, setup, and wave-driven mean flows were made on a steep coral forereef its associated lagoonal system the north shore Moorea, French Polynesia. Despite complex geometry forereef, wave amplitudes that are nearly equal to water depth, linear theory showed very good agreement with data. Measurements across reef illustrate importance including both transport (owing Stokes drift), as well Eulerian when computing fluxes over reef. Finally, observed setup closely...
We observed transient stratification and mixing events associated with nearshore internal bores in southern Monterey Bay using an array of instruments high spatial temporal resolution. The arrival the is characterized by surging masses dense (cold) water that tend to stratify column. bore followed a gradual drop temperature throughout column over several hours (defined here as period) until sharp warm‐front relaxation, frequency fluctuations, returns back nearly its original state period)....
We present a Lagrangian analysis of nonlinear surface waves propagating zonally on zonal current in the presence Earth’s rotation that shows existence two modes wave motion. The first, ‘fast’ mode, one with wavelengths commonly found for wind and swell ocean, represents wave–current interaction counterpart rotationally modified Gerstner first by Pollard ( J. Geophys. Res. , vol. 75, 1970, pp. 5895–5898) quite closely resemble Stokes waves. second, slower, mode has period nearly equal to...
Hydrodynamic consequences of using simpler geometric shapes to represent coral canopies are examined through a laboratory study. A canopy composed cylinders is compared with 3-D-printed, scaled down heads in recirculating flume. Vertical velocity profiles measured at four horizontal locations for each type, and mean turbulence statistics both within above the canopy. narrow, defined wake on scale element present behind cylinder elements that absent There also peak shear stress top canopy,...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 187:17-30 (1999) - doi:10.3354/meps187017 Processes governing phytoplankton blooms in estuaries. II: The role of horizontal transport Lisa V. Lucas1,*, Jeffrey R. Koseff2, Stephen G. Monismith2, James E. Cloern1, Janet K. Thompson1,2 1United States Geological Survey, 345 Middlefield Road, MS #496, Menlo Park,...
Communities of benthic organisms can form very rough surfaces (canopies) on the seafloor. Previous studies have shown that an oscillatory flow induced by monochromatic surface waves will drive more inside a canopy than comparable unidirectional current. This paper builds these previous investigating how wave energy is attenuated within canopies under spectral conditions, or random fields defined many frequencies. A theoretical model first developed to predict attenuation varies among...