Autonomous Ocean Measurements in the California Current Ecosystem

Abstract

Event-scale phenomena, of limited temporal duration or restricted spatial extent, often play a disproportionately large role in ecological processes occurring in the ocean water column. Nutrient and gas fluxes, upwelling and downwelling, transport of biogeochemically important elements, predator-prey interactions, and other processes may be markedly influenced by such events, which are inadequately resolved from infrequent ship surveys. The advent of autonomous instrumentation, including underwater gliders, profiling floats, surface drifters, enhanced moorings, coastal high-frequency radars, and satellite remote sensing, now provides the capability to resolve such phenomena and assess their role in structuring pelagic ecosystems. These methods are especially valuable when integrated together, and with shipboard calibration measurements and experimental programs

Submesoscale CO<sub>2</sub> variability across an upwelling front off Peru

“…When coupled with CO 2 measurements the use of sea surface temperature and wind products, which capture the high temporal and spatial variability, could lead to improved future estimates of a CO 2 flux climatology off Peru. In order to understand the large-scale impact of short-term variability of an upwelling ecosystem, one way forward would be the establishment of multi-platform observation networks in which continuous in situ data are complemented by satellite observations and measurements from autonomous platforms (e.g., gliders, as those conducted by Ohman et al (2013) in the California Current System. A further example is the moored CO 2 observations from Lefèvre et al (2008) and Lefèvre and Merlivat (2012) which help to constrain regional budgets and variability of CO 2 for the eastern tropical Atlantic and could also be used to reliably estimate the net carbon community production in this area.…”

Next Generation of Advanced Laser Fluorescence Technology for Characterization of Natural Aquatic Environments

“…The three-laser ALF-T instrument was eqiupped with 375, 405, and 514 nm lasers and deployed in 2012 and 2013 in the Gulf of Mexico to assess consequences and bio-envornmental impacts of the Deepwater Horizon oil spill of 2010 and support NASA field program for sea-truthing future geo-stationary satellite (Fig. 13) The various versions of the ALFA instrument were extensively tested and refined in a series of field deployments in the Bering Sea [6], Gulf of Mexico, Amazon River plume [7], and California Current [3][4][5][6]. The new ALFA instrument was successfully demonstrated at the AGU/ASLO Ocean Sciences meeting (Salt Lake City, 2012; Fig.…”

“…Two ALFA instruments were build to order from Scripps Institution of Oceanography (San Diego, CA) and State Key Laboratory of Marine Environmental Science, Xiamen University (China) in 2011 and 2013, respectively. The former instrument has been operationally integrated into the California Current Ecosystem Long-Term Ecological Research (CCE LTER) program (NSF) and extensively used for their studies since 2011 [3, 4,11]. The LDEO and WET Labs ALF teams have recently conducted on request of the Xiamen University training of the technical personnel repsonsible for the ALFA maintanance and deloyments.…”

“…Refinement of ALF analytical algorithms. The ALF analytical algorithms were further refined, including improved fluorescence assessment of chlorophyll concentration [2, 3], extension of the ALF analytical capabilities for assessment of phytoplankton biomass and community composition [3], as well as assessments of the key aquatic fluorescence constituents, and phytoplankton photophysiological parameters [2][3][4][5][6][7][8]. Photo-physiological variability of in vivo chlorophyll fluorescence (CF) per unit of chlorophyll concentration (CC) was analyzed using a biophysical model to improve the accuracy of CC assessments [2].…”

Absolute Velocity Estimates from Autonomous Underwater Gliders Equipped with Doppler Current Profilers

“…4a) from 14 July to 30 October 2015 as part of the ongoing California Underwater Glider Network (Davis et al 2008;Todd et al 2011bTodd et al ,a, 2012Ohman et al 2013;Johnston and Rudnick 2015;Zaba and Rudnick 2016;Rudnick et al 2016). The glider completed four cross-shore transects from the coast to approximately 525 km offshore, sampling from the surface to 500 m approximately every 3 h. The glider had little growth on it upon recovery.…”