The propagating response of inner shelf circulation to wind relaxations along the central California Coast
Following relaxations prevailing equatorward winds, warm water from the Santa Barbara Channel flows poleward around Point Conception and along the central California coast. Sequences of satellite sea surface temperature images show the events as bands of warm water extending up to 20 km offshore. Characteristics of these flows were examined using time series of currents and temperature from an array of moorings along the inner shelf (15 m depth), a mooring on the mid-shelf (100 m depth), and surface current observations from high frequency radars.
Measuring zooplankton aggregations at oceanic fronts in the California Current using autonomous gliders
Autonomous gliders traversing across shore sections of the California Current are powerful tools for continously measuring hydrographic properties, chlorophyll a fluorescence and acoustic backscatter (at 750kHz) in the CCE study area. Sharp fronts in hydrographic properties seem to co-occur with biological fronts assoctiated with chl a fluorescence and acoustic backscatter (which is a rough proxy for zoolankton biomass). This poster examines criteria for defining both physical and biological fronts as well as the strength of interaction between the fronts.
On the CCE Process Cruises in the California Current System, we used a Lagrangian sampling design to identify and track a series of discrete water parcels and entrained plankton communities through time.
The California Current System is a coastal upwelling biome, as found along the eastern margins of all major ocean basins. These are among the more productive ecosystems in the world ocean. The California Current Ecosystem (CCE) LTER site (centered on 32.9° N, 120.3° W) is investigating nonlinear transitions in the California Current coastal pelagic ecosystem, with particular attention to long-term forcing by a secular warming trend, multi-decadal oscillations (e.g., PDO and NPGO), and ENSO in altering the structure and dynamics of the pelagic ecosystem.
During May and June of 2006, the LTER CCE program launched a cruise off Point Conception closely following the California Cooperative Oceanic Fisheries Investigations (CalCOFI) line 80 and a valuable dataset was collected. These ocean variables include along-flow and cross-flow spatial gradients, vertical current shear, CTD and iron limitation.
Experimental studies of phytoplankton growth and grazing processes were conducted in the California Current Ecosystem off Point Conception, California to test the hypothesis that growth and grazing losses determine, to first order, the local dynamics of phytoplankton in the upwelling circulation.
The exchange of water between coral reef lagoons and the open ocean depends on the interplay between waves, buoyancy, wind stress, and alongshore currents. Some processes act to retain lagoon water such as onshore flows driven by surface waves, while others (e.g., the momentum jet that exits the lagoon) export lagoon water. To explore the impact of surface waves on the exchange dynamics, observations were made in Paopao Bay, French Polynesia, a nearly tideless coral reef lagoon system.
The marine microbial community, consisting of autotrophic and heterotrophic bacteria and protists (< 200 µm), is challenging to study due to its high diversity, various trophic functions, and poorly resolved taxonomy. However, the inherent property of organism size, determined by microscopical and flow cytometric techniques, can be used to develop population and community size spectra, which summarize large amounts of information into a simplified format.
Autonomous robotic surveys of Adélie penguin foraging “hot spots” offshore of Palmer Station, Antarctica
The distribution of Adélie penguins along the West Antarctic Peninsula (WAP) is spatially heterogeneous. Large Adélie colonies occur spatially in regions characterized by deep seafloor canyons. Often associated with these regions is persistent upwelling of warm, nutrient-rich UCDW, which is hypothesized to provide a predictable food resource close to the colonies such that they can be accessed by the penguins given their limited foraging range.
Using Webb gliders to study the physical regulation of ecosystem dynamics at Palmer Station Antarctica
A Webb Slocum glider was launched on Western Antarctic Peninsula (WAP) launched out of the U.S. Palmer Research Station. The glider mission covered >600 km, providing >1400 ocean profiles. The glider profiles, in combination with Adélie penguin foraging data (from penguins tagged with ARGOS-linked tracking instruments), showed that Adélie penguins in the area of Palmer station forage just at the base of the chlorophyll maximum, which may provide improved visibility for these visual foragers.