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© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zhang, Y., Kieft, B., Hobson, B. W., Ryan, J. P., Barone, B., Preston, C. M., Roman, B., Raanan, B., Marin,Roman,,III, O'Reilly, T. C., Rueda, C. A., Pargett, D., Yamahara, K. M., Poulos, S., Romano, A., Foreman, G., Ramm, H., Wilson, S. T., DeLong, E. F., Karl, D. M., Birch, J. M., Bellingham, J. G., & Scholin, C. A. Autonomous tracking and sampling of the deep chlorophyll maximum layer in an open-ocean eddy by a long-range autonomous underwater vehicle. IEEE Journal of Oceanic Engineering, 45(4), (2020): 1308-1321, doi:10.1109/JOE.2019.2920217., Phytoplankton communities residing in the open ocean, the largest habitat on Earth, play a key role in global primary production. Through their influence on nutrient supply to the euphotic zone, open-ocean eddies impact the magnitude of primary production and its spatial and temporal distributions. It is important to gain a deeper understanding of the microbial ecology of marine ecosystems under the influence of eddy physics with the aid of advanced technologies. In March and April 2018, we deployed autonomous underwater and surface vehicles in a cyclonic eddy in the North Pacific Subtropical Gyre to investigate the variability of the microbial community in the deep chlorophyll maximum (DCM) layer. One long-range autonomous underwater vehicle (LRAUV) carrying a third-generation Environmental Sample Processor (3G-ESP) autonomously tracked and sampled the DCM layer for four days without surfacing. The sampling LRAUV's vertical position in the DCM layer was maintained by locking onto the isotherm corresponding to the chlorophyll peak. The vehicle ran on tight circles while drifting with the eddy current. This mode of operation enabled a quasi-Lagrangian time series focused on sampling the temporal variation of the DCM population. A companion LRAUV surveyed a cylindrical volume around the sampling LRAUV to monitor spatial and temporal variation in contextual water column properties. The simultaneous sampling and mapping enabled observation of DCM microbial community in its natural frame of reference., 10.13039/501100008982 - National Science Foundation 10.13039/100000936 - Gordon and Betty Moore Foundation 10.13039/100000008 - David and Lucile Packard Foundation 10.13039/100016377 - Schmidt Ocean Institute 10.13039/100000893 - Simons Foundation

Environmental DNA (eDNA) is increasingly used for monitoring marine organisms; however, offshore sampling and time lag from sampling to results remain problematic. In order to overcome these challenges a robotic sampler, a 2nd generation Environmental Sample Processor (ESP), was tested for autonomous analysis of eDNA from four commercial fish species in a 4.5 million liter mesocosm. The ESP enabled in situ analysis, consisting of water collection, filtration, DNA extraction and qPCR analysis, which allowed for real-time remote reporting and archival sample collection, consisting of water collection, filtration and chemical preservation followed by post-deployment laboratory analysis. The results demonstrate that the 2G ESP was able to consistently detect and quantify target molecules from the most abundant species (Atlantic mackerel) both in real-time and from the archived samples. In contrast, detection of low abundant species was challenged by both biological and technical aspects coupled to the ecology of eDNA and the 2G ESP instrumentation. Comparison of the in situ analysis and archival samples demonstrated variance, which potentially was linked to diel migration patterns of the Atlantic mackerel. The study demonstrates strong potential for remote autonomous in situ monitoring which open new possibilities for the field of eDNA and marine monitoring.

A wording error in a sentence in the abstract misrepresented a main finding of the research. The sentence should read: Expression of the demethylation pathway was relatively greater during a high-DMSP-producing dinoflagellate bloom, and expression of the cleavage pathway was greater in the presence of a mixed diatom and dinoflagellate community. The sentence has now been corrected. The supplementary file published with the paper was missing figure legends. The correct file is now provided.

This thesis aims to design a mobile module with the multifunction relays, which CELEC EP HIDROPAUTE have stored in the cellars of the Mazar plant. It will minimize unscheduled downtime of the units of the Molino plant, due to a failure in protection relays, which are electromechanical and solid state, so that it replaces the relays currently installed in the system protection unit where failure has happened. First, we did a fieldwork, it consists to obtain all information about protections system of the Molino plant both planes, equipment installed and current protection relays’ calibrations. Furthermore, we investigated the characteristicsof the multifunction relays available in cellars of the Mazar plant, in order to select the most suitable for installation in mobile module. The design of the mobile module was developed in three stages; the first one was set multifunction relay so that its operation is as close as possible to the electromechanical relays and solid state currently installed. The second one was performing both electrical and mechanical design of the module,so that it meets all technical requirements for a hydroelectric plant. In the third stage, the procedure to replace the currently installed relays with mobile module with multifunction relays was made. Then we made a referential budget and timeline of the construction process. Finally, we made injection signals tests on multifunction relays in order to corroborate that the calibrations of different backup protection functions are similar to the current operating system protections.

Oscillating diurnal rhythms of gene transcription, metabolic activity, and behavior are found in all three domains of life. However, diel cycles in naturally occurring heterotrophic bacteria and archaea have rarely been observed. Here, we report time-resolved whole-genome transcriptome profiles of multiple, naturally occurring oceanic bacterial populations sampled in situ over 3 days. As anticipated, the cyanobacterial transcriptome exhibited pronounced diel periodicity. Unexpectedly, several different heterotrophic bacterioplankton groups also displayed diel cycling in many of their gene transcripts. Furthermore, diel oscillations in different heterotrophic bacterial groups suggested population-specific timing of peak transcript expression in a variety of metabolic gene suites. These staggered multispecies waves of diel gene transcription may influence both the tempo and the mode of matter and energy transformation in the sea., Gordon and Betty Moore Foundation (GBMF 492.01), Gordon and Betty Moore Foundation (GBMF 3777), National Science Foundation (U.S.) (Grant EF0424599), David & Lucile Packard Foundation

Nitrogen-fixing microorganisms (diazotrophs) are keystone species that reduce atmospheric dinitrogen (N2) gas to fixed nitrogen (N), thereby accounting for much of N-based new production annually in the oligotrophic North Pacific. However, current approaches to study N2 fixation provide relatively limited spatiotemporal sampling resolution; hence, little is known about the ecological controls on these microorganisms or the scales over which they change. In the present study, we used a drifting robotic gene sensor to obtain high-resolution data on the distributions and abundances of N2-fixing populations over small spatiotemporal scales. The resulting measurements demonstrate that concentrations of N2 fixers can be highly variable, changing in abundance by nearly three orders of magnitude in less than 2 days and 30 km. Concurrent shipboard measurements and long-term time-series sampling uncovered a striking and previously unrecognized correlation between phosphate, which is undergoing long-term change in the region, and N2-fixing cyanobacterial abundances. These results underscore the value of high-resolution sampling and its applications for modeling the effects of global change.

Planktonic microbial activity and community structure is dynamic, and can change dramatically on time scales of hours to days. Yet for logistical reasons, this temporal scale is typically under-sampled in the marine environment. In order to facilitate higher-resolution, long-term observation of microbial diversity and activity, we developed a protocol for automated collection and fixation of marine microbes using the Environmental Sample Processor (ESP) platform. The protocol applies a preservative (RNALater) to cells collected on filters, for long-term storage and preservation of total cellular RNA. Microbial samples preserved using this protocol yielded high-quality RNA after 30 days of storage at room temperature, or onboard the ESP at in situ temperatures. Pyrosequencing of complementary DNA libraries generated from ESP-collected and preserved samples yielded transcript abundance profiles nearly indistinguishable from those derived from conventionally treated replicate samples. To demonstrate the utility of the method, we used a moored ESP to remotely and autonomously collect Monterey Bay seawater for metatranscriptomic analysis. Community RNA was extracted and pyrosequenced from samples collected at four time points over the course of a single day. In all four samples, the oxygenic photoautotrophs were predominantly eukaryotic, while the bacterial community was dominated by Polaribacter-like Flavobacteria and a Rhodobacterales bacterium sharing high similarity with Rhodobacterales sp. HTCC2255. However, each time point was associated with distinct species abundance and gene transcript profiles. These laboratory and field tests confirmed that autonomous collection and preservation is a feasible and useful approach for characterizing the expressed genes and environmental responses of marine microbial communities.