Computational Studies of Three-Dimensional Ocean Sound Fields in Areas of Complex Seafloor Topography and Active Ocean Dynamics

Time-evolving three-dimensional (four-dimensional) numerical modeling of sound is performed for ocean environmental conditions calculated using regional ocean flow models. The flow models solve the appropriate nonlinear equations in bands of resolved scales and frequencies. Subgrid scale processes are parameterized, as are boundary processes. The ocean fields are interpolated onto acoustic model grids that are two orders of magnitude tighter than the flow model grids. The computations provide reliable estimates of the acoustic effects of the resolved ocean processes such as geostrophic currents, mixed-layer changes, and internal tides, but they do not include the acoustic implications of unresolved structures such as nonlinear internal waves, sharp boundary layers, and small-scale intrusions. Examples of complicated sound fields from resolved and unresolved features will be presented, and prospects for applying the methods will be discussed

Exploring the use of environmental DNA (eDNA) to detect animal taxa in the Mesopelagic Zone

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Govindarajan, A. F., Francolini, R. D., Jech, J. M., Lavery, A. C., Llopiz, J. K., Wiebe, P. H., & Zhang, W. Exploring the use of environmental DNA (eDNA) to detect animal taxa in the Mesopelagic Zone. Frontiers in Ecology and Evolution, 9, (2021): 574877, https://doi.org/10.3389/fevo.2021.574877.Animal biodiversity in the ocean’s vast mesopelagic zone is relatively poorly studied due to technological and logistical challenges. Environmental DNA (eDNA) analyses show great promise for efficiently characterizing biodiversity and could provide new insight into the presence of mesopelagic species, including those that are missed by traditional net sampling. Here, we explore the utility of eDNA for identifying animal taxa. We describe the results from an August 2018 cruise in Slope Water off the northeast United States. Samples for eDNA analysis were collected using Niskin bottles during five CTD casts. Sampling depths along each cast were selected based on the presence of biomass as indicated by the shipboard Simrad EK60 echosounder. Metabarcoding of the 18S V9 gene region was used to assess taxonomic diversity. eDNA metabarcoding results were compared with those from net-collected (MOCNESS) plankton samples. We found that the MOCNESS sampling recovered more animal taxa, but the number of taxa detected per liter of water sampled was significantly higher in the eDNA samples. eDNA was especially useful for detecting delicate gelatinous animals which are undersampled by nets. We also detected eDNA changes in community composition with depth, but not with sample collection time (day vs. night). We provide recommendations for applying eDNA-based methods in the mesopelagic including the need for studies enabling interpretation of eDNA signals and improvement of barcode reference databases.This research was part of the Woods Hole Oceanographic Institution’s Ocean Twilight Zone Project, funded as part of The Audacious Project housed at TED. Funding for the NOAA Ship Henry B Bigelow was provided by NOAA’s Office of Marine and Aviation Operations (OMAO)

Issues and progress in the prediction of ocean submesoscale features and internal waves

Data-constrained dynamical ocean modeling for the purpose of detailed forecasting and prediction continues to evolve and improve in quality. Modeling methods and computational capabilities have each improved. The result is that mesoscale phenomena can be modeled with skill, given sufficient data. However, many submesoscale features are less well modeled and remain largely unpredicted from a deterministic event standpoint, and possibly also from a statistical property standpoint. A multi-institution project is underway with goals of uncovering more of the details of a few submesoscale processes, working toward better predictions of their occurrence and their variability. A further component of our project is application of the new ocean models to ocean acoustic modeling and prediction. This paper focuses on one portion of the ongoing work: Efforts to link nonhydrostatic-physics models of continental-shelf nonlinear internal wave evolution to data-driven regional models. Ocean front-related effects are also touched on.United States. Office of Naval Research (United States. Dept. of Defense. Multidisciplinary University Research Initiative (Ocean Acoustics Program Award N00014-11-1-0701))United States. Office of Naval Research (Grant N00014-12-1-0944)National Science Foundation (U.S.) (Grant OCE-1061160

Multiscale multiphysics data-informed modeling for three-dimensional ocean acoustic simulation and prediction

Author Posting. © Acoustical Society of America, 2019. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 146(3), (2019): 1996-2015, doi:10.1121/1.5126012.Three-dimensional (3D) underwater sound field computations have been used for a few decades to understand sound propagation effects above sloped seabeds and in areas with strong 3D temperature and salinity variations. For an approximate simulation of effects in nature, the necessary 3D sound-speed field can be made from snapshots of temperature and salinity from an operational data-driven regional ocean model. However, these models invariably have resolution constraints and physics approximations that exclude features that can have strong effects on acoustics, example features being strong submesoscale fronts and nonhydrostatic nonlinear internal waves (NNIWs). Here, work to predict NNIW fields to improve 3D acoustic forecasts using an NNIW model nested in a tide-inclusive data-assimilating regional model is reported. The work was initiated under the Integrated Ocean Dynamics and Acoustics project. The project investigated ocean dynamical processes that affect important details of sound-propagation, with a focus on those with strong intermittency (high kurtosis) that are challenging to predict deterministically. Strong internal tides and NNIW are two such phenomena, with the former being precursors to NNIW, often feeding energy to them. Successful aspects of the modeling are reported along with weaknesses and unresolved issues identified in the course of the work.This work was supported by Department of Defense Multidisciplinary University Initiative (MURI) Grant No. N00014-11-1-0701, managed by the Office of Naval Research Ocean Acoustics Program, and National Science Foundation Grant No. OCE-1060430. Final manuscript preparation was supported by ONR Ocean Acoustics Grant Nos. N00014-17-1-2624 and N00014-17-1-2692. P.F.J.L. also thanks ONR and NSF for research support under Grant Nos. N00014-13-1-0518 (Multi-DA) and OCE-1061160 (ShelfIT) to MIT, respectively. The MSEAS-based series of simulations for the New Jersey shelf region examined here was accelerated toward completion by the interest in realistic 3D acoustic fields expressed by Dr. Ivars Kirsteins at the Naval Undersea Warfare Center.2020-03-3

Video Plankton Recorder environmental sensor data from the first cruise of SPIROPA project aboard the R/V Neil Armstrong on April 26, 2018

Dataset: AR29 VPR-log Transect 23Video Plankton Recorder environmental sensor data from the first cruise of SPIROPA project in April 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/805392NSF Division of Ocean Sciences (NSF OCE) OCE-165780

Bottle sample data and water processing samples from CTD casts from the first cruise of SPIROPA project, R/V Neil Armstrong cruise AR29, to the New England Shelfbreak in April 2018.

Dataset: Bottle AR29Bottle sample data and water processing samples from CTD casts from the first cruise of SPIROPA project, R/V Neil Armstrong cruise AR29, to the New England Shelfbreak in April 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/863240NSF Division of Ocean Sciences (NSF OCE) OCE-165780

CTD casts from the SPIROPA project from R/V Neil Armstrong cruise AR29 and R/V Thomas G. Thompson cruise TN368 to the New England Shelfbreak in 2018 and 2019

Dataset: CTD AR29 and TN368: Diatom Hotspot DataCTD casts from the first cruise and third cruises of the SPIROPA project. The first cruise (AR29 Transect 24), took place aboard the R/V Neil Armstrong in April 2018 and the third cruise (TN368) took place on the R/V Thomas G. Thompson cruise in July of 2019. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/807119NSF Division of Ocean Sciences (NSF OCE) OCE-165780

CTD casts from the first cruise of SPIROPA project aboard the R/V Neil Armstrong on April 27, 2018.

Dataset: AR29 CTD Transect 24CTD casts from the first cruise of SPIROPA project in April 2018 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/807119NSF Division of Ocean Sciences (NSF OCE) OCE-165780

Video Plankton Recorder environmental sensor data from the first cruise of SPIROPA project aboard the R/V Neil Armstrong to the New England Shelfbreak in April, 2018

Dataset: VPR AR29Video Plankton Recorder environmental sensor data from the first cruise of SPIROPA project aboard the R/V Neil Armstrong to the New England Shelfbreak in April, 2018 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/805392NSF Division of Ocean Sciences (NSF OCE) OCE-165780

Video Plankton Recorder environmental sensor data from the third cruise of SPIROPA project, R/V Thomas G. Thompson cruise TN368, to the New England Shelfbreak in July of 2019

Dataset: TN368 VPR: Diatom Hotspot DataVideo Plankton Recorder environmental sensor data from the third cruise of SPIROPA project, R/V Thomas G. Thompson cruise TN368, to the New England Shelfbreak in July of 2019. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/848898NSF Division of Ocean Sciences (NSF OCE) OCE-165780