We now have two gliders sampling this bloom. RU23 seen in the upper right of the map below is transecting west from a deployment off Martha’s Vineyard. This glider will continue to the west into the lower concentrations associated with the bloom further offshore. The color overlay on the map is Chl Concentration observed from the MODIS satellite sensor. Red are higher values and pink are near zero values.
Since reaching the the inshore waypoint, ru16 has begun to fly back offshore along the same line. Our intention with this glider is to capture the cross-shelf variation in dissolved oxygen associated with the bloom. The glider shows us that the water column is still very stratified with more mixed conditions right near the coast (below).
The dissolved oxygen also shows a two layer system with higher concentrations in the surface layer and lower concentrations in the bottom layer, particularly closer to shore. The distribution of oxygen is seen in a histogram of the last transect showing the bi-modal distribution with surface values (7-8.5 mg/L) and bottom values (3.6 – 5.2 mg/L).
Over the next several days we will position the gliders in the deeper water of the mid-shelf to sample through the forecasted hurricane coming this weekend. Following the storm the gliders will move inshore to sample the impact of the storm on the bloom and associated dissolved oxygen.