NWT RESEARCH DATABASE

Tags: physical sciences, water quality, oceanography, carbon fluxes, marine ecosystem

Objective(s): To collect physical, biological and chemical observations in the Eastern Beaufort Sea from moored and moving platforms; to describe and analyze physical, biological and chemical observations acquired from the moving platforms; and to gather water and sediment samples at the mooring locations, and process and analyze these samples to estimate the carbon budget and describe carbon cycling processes.

Project Description: The Bureau of Ocean Energy Management issued a request for a program during the 2016 field season to accomplish the following objectives: • Collect physical, biological and chemical observations in the Eastern Beaufort Sea from moored and moving platforms; • Describe and analyze physical, biological and chemical observations acquired from the moving platforms; and • Gather water and sediment samples at the mooring locations, and process and analyze these samples to estimate the carbon budget and describe carbon cycling processes. The field program will be implemented in an integrated way to provide a comprehensive picture of the system as allowable by available resources, focusing on key measurements known to be relevant to ecosystem questions. The field program component includes deployment of four moorings, deployment and recovery of an autonomous glider and carbon cycling measurements. Stantec will deploy four new ecosystem moorings, which, thanks to close collaboration with our colleagues at University of Alaska Fairbanks and Fisheries and Oceans Canada, will result in a unique six mooring cross shelf array. The moorings will be deployed in early October 2016, between October 4-10 depending on weather, by the Canadian Coast Guard Ship (Icebreaker) Sir Wilfrid Laurier as part of the integrated Beaufort Observatory mooring cruise taking place in the Canadian Beaufort Sea. The current plan is to deploy this October, retrieve and redeploy (all in one cruise) in October 2017, and then retrieve for good in October 2018. The equipment and sensors include a McLane MMP PAR Fluoro Sensor Module (Fluorescence), SBE-37IM CTD (Conductivity, Temperature and Depth), ADCP (Acoustic Doppler Current Profilers at 300, or 150 and 75 kHz depending on depth), ULS (Upward-Looking Sonar or Ice Profiling Sonar, IPS), and AZFPs (Acoustic Zooplankton Fish Profilers at 38 kHz, and at125, 200, 460 ad 770 kHz), and a PAM (Passive Acoustics Monitor) will be deployed. To achieve robust environmental context, this array will be further supplemented with two SAMI pCO2 sensors (from UAF) and three SUNA nitrate sensors (from WHOI). The main objectives of the glider program are to (1) map spatial distribution of the Mackenzie plume from the U.S.-Canadian border to the head of the Mackenzie Trough, (2) characterize the along-shelf and cross-shelf structure of the shelf-break jet and shelf water masses in the vicinity of the Mackenzie Trough, (3) quantify the associated biological response to the physical conditions of the water column, and (4) provide an extended geographic sampling regime of key parameters measured by the moorings. To meet these objectives, the Stantec team will deploy one lithium battery-powered Slocum glider from the R/V Ukpik (out of Prudhoe Bay) in the eastern Beaufort Sea close to the Canadian border in the second half of August 2016. Deployment is planned for August 16-18, 2016, depending on weather conditions. Glider recovery will occur by mooring cruise once these are deployed, around October 8-10. The glider will be picked up by the CCGS Sir Wilfrid Laurier after the moorings are deployed in early October2016. The total glider mission is estimated to be approximately 45 days, depending the timing of deployment and pickup. The glider will, at the minimum, sample three cross-shelf and two along-shelf transects. The glider will be equipped with CTD, Dissolved Oxygen optode, chlorophyll-a fluorometer, Colored Dissolved Organic Matter (CDOM) sensor, optical backscattering at 700nm, Photosynthetically Active Radiation (PAR) sensor, and an Imagenex Eco Sounder (120kHz). The raw physical, bio-optical, and bio-acoustics glider data will be stored onboard the glider science computer to be downloaded upon recovery. A designated subset of the data for each sensor will be transmitted back to the data server at VIMS in real time to track performance of the glider-mounted sensors. All glider data will be analyzed within their own context toward the objectives listed above and later integrated with the mooring data. The research team will collect water and sediment samples in October of 2016. Sediment samples will be collected using a box core. Tandem measures of meiofaunal abundance and biomass from subsets of the same sediments will allow the fraction of carbon transferred to resident benthic meiofauna to be assessed. These new samples will be augmented by a detailed organic analysis of a subset of archived samples from earlier programs (SBI, ANAMIDA), plus several samples available from colleagues with ongoing projects in the region (e.g. lagoon sediments in the eastern Beaufort) to provide boundaries for organic carbon composition, retention and model development. The field program is an addition to existing work conducted aboard the CCGS Sir Wilfrid Laurier. Kavik-Stantec personnel will present updates, reports and information to the Aklavik, Inuvik and Tuktoyaktuk Hunters and Trappers Committees. Updates and public reports will also be provided to the Aurora Research Institute. The fieldwork for this study will be conducted from August 19, 2016 to October 15, 2016.