We just returned from a short offshore survey along the Newport Line out to 200 miles aboard the Bell M. Shimada. There was relatively strong upwelling favorable winds and clear skies in the days leading up to our departure. This made us quite excited to see how the ocean had responded- would there be an early phytoplankton bloom, would we see newly upwelled water nearshore?
The clear skies continued during our survey and the outside air temperature and the ocean were quite cold. Surface water temperatures were 8 - 9 °C and the water column was well mixed. We did not see a distinct phytoplankton bloom and the water was mostly clear. The plankton samples were clean, which is what we'd expect for winter. However, the samples were also quite pink and filled with large zooplankton indicative of a productive ocean. For example, Neocalanus, a copepod with sub-arctic water mass affinities was ubiquitous in the samples.
Image of a plankton sample under the dissecting microscope. Notice the large and many small pteropods Limacina helicina. Some Limacina were still in their larval form, indicating that we observed a recent spawning event. Photo: NOAA Fisheries
We also think we observed recent spawning of pteropods (pelagic gastropods) at many of our stations. The evidence that led us to this hypothesis, was we observed both large and small pteropods in the same plankton sample at many of the stations. The small pteropods were very abundant and some were still veliger larvae, with their ciliated velum clearly visible under the microscope.
Plankton samples collected from 1 - 25 miles (top row), 35 - 105 miles (middle row), and 125 - 200 miles (bottom row) from shore. Notice the pink color of the samples and then the brown color as we moved offshore. Photo: NOAA Fisheries
As we moved offshore, the samples were browner than onshore because of the presence of phaeodarians, which we have talked about in previous posts.
All in all, this looks to be shaping up to be a productive winter so far. Stay tuned to see how things change as we move into the spring upwelling season.