Numerical modeling of thermal bar and stratification pattern in Lake Ontario using the EFDC model

Thermal bar is an important phenomenon in large, temperate lakes like Lake Ontario. Spring thermal bar formation reduces horizontal mixing, which in turn, inhibits the exchange of nutrients. Evolution of the spring thermal bar through Lake Ontario is simulated using the 3D hydrodynamic model Environmental Fluid Dynamics Code (EFDC). The model is forced with the hourly meteorological data from weather stations around the lake, flow data for Niagara and St. Lawrence rivers, and lake bathymetry. The simulation is performed from April to July, 2011; on a 2-km grid. The numerical model has been calibrated by specifying: appropriate initial temperature and solar radiation attenuation coefficients. The existing evaporation algorithm in EFDC is updated to modified mass transfer approach to ensure correct simulation of evaporation rate and latent heatflux. Reasonable values for mixing coefficients are specified based on sensitivity analyses. The model simulates overall surface temperature profiles well (RMSEs between 1-2°C). The vertical temperature profiles during the lake mixed phase are captured well (RMSEs < 0.5°C), indicating that the model sufficiently replicates the thermal bar evolution process. An update of vertical mixing coefficients is under investigation to improve the summer thermal stratification pattern. Keywords: Hydrodynamics, Thermal BAR, Lake Ontario, GIS

ICTC12 Abstract Book

Abstract book for the 12th International Conference on Toxic Cyanobacteria

Workshop on the socio-economic effects of marine and fresh water harmful algal blooms in the United States

Presented at Workshop on the Socio-economic Effects of Marine and Fresh Water Harmful Algal Blooms in the United States, July 27 - August 5, 2020The US National Office for Harmful Algal Blooms at the Woods Hole Oceanographic Institution (WHOI) and the NOAA National Centers for Coastal Ocean Science (NCCOS) held a virtual workshop comprising four sessions between July 27 and August 5, 2020. This report summarizes the workshop proceedings and presents recommendations developed by participants during the discussion. The recommendations advance an assessment framework and a national research agenda that will lead to comprehensive evaluations of the socio-economic effects of harmful algal blooms (HABs) in fresh water (primarily the Great Lakes) and marine waters of the United States.Cooperative Institute for the North Atlantic Region (CINAR): NA14OAR4320158 and NA19NOS478018

Biodiversity of Marine Microbes

The book entitled “Biodiversity of Marine Microbes” aims at highlighting the significance of marine microbes as primary producers, their contribution in complex ecological processes and their roles in biogeochemical cycles and ecosystem functioning. The book includes five research papers covering the diversity and composition of marine microbial communities representing all three domains of life in various marine environments, including coastal eutrophic areas, ice waters, and lagoons. One paper examines the diversity and succession of bacterial and archaeal communities from coastal waters in mesocosm experiments. The combination of classical tools with novel technological advances implemented in the methods of the papers offered an opportunity to answer fundamental questions and shed light on the complex and diverse life of marine microbes

Investigating summer thermal stratification in Lake Ontario

Summer thermal stratification in Lake Ontario is simulated using the 3D hydrodynamic model Environmental Fluid Dynamics Code (EFDC). Summer temperature differences establish strong vertical density gradients (thermocline) between the epilimnion and hypolimnion. Capturing the stratification and thermocline formation has been a challenge in modeling Great Lakes. Deviating from EFDC's original Mellor-Yamada (1982) vertical mixing scheme, we have implemented an unidimensional vertical model that uses different eddy diffusivity formulations above and below the thermocline (Vincon-Leite, 1991; Vincon-Leite et al., 2014). The model is forced with the hourly meteorological data from weather stations around the lake, flow data for Niagara and St. Lawrence rivers; and lake bathymetry is interpolated on a 2-km grid. The model has 20 vertical layers following sigma vertical coordinates. Sensitivity of the model to vertical layers' spacing is thoroughly investigated. The model has been calibrated for appropriate solar radiation coefficients and horizontal mixing coefficients. Overall the new implemented diffusivity algorithm shows some successes in capturing the thermal stratification with RMSE values between 2-3°C. Calibration of vertical mixing coefficients is under investigation to capture the improved thermal stratification

PICES Press, Vol. 23, No. 2, Summer 2015

The 2015 Inter-sessional Science Board meeting: A note from the Science Board Chairman (pp. 1-3); 2015 Symposium on “Effects of climate change on the world’s oceans” (pp. 4-7); 2015 Santos Joint BrOA and SOLAS Workshop (pp. 8-8); 2015 Santos Workshop on “Effects of climate change on the biologically-driven ocean carbon pumps” (pp. 9-11); 2015 Santos Workshop on “Upwelling systems under future climate change” (pp. 12-13); 2015 Santos Workshop on “Moving towards climate-ready fishery systems” (pp. 14-16); International Symposium on “Pacific salmon and steelhead production in a changing climate” (pp. 17-21); Mitigation of harmful algal blooms: The way forward (pp. 22-24); S-HAB contributions to FUTURE (pp. 25-27); A psychological perspective on “human well-being” (pp. 28-29); PICES calendar of events (pp-30-30); A good relationship between local communities and seafood diversity (pp. 31-31); Modeling the drift of marine debris generated by the 2011 tsunami in Japan (pp. 32-36); Opening of the Hakodate Research Center for Fisheries and Oceans (pp. 37-38); The state of the western North Pacific during the 2014/2015 cold season (pp. 39-40); The Bering Sea: Current status and recent trends (pp. 41-43); The warm Blob continues to dominate the ecosystem of the northern California Current (pp. 44-46); 2015 Pacific Ecology and Evolution Conference (pp. 47-48