Algae Observed in Satellite Image - Could This Be Related to Shearwater Die-offs?

Observation by Mike Brubaker:

I was reviewing satellite imagery yesterday, looking at the smoke plumes from the wildfires in Alaska and I noticed this large area in the Bering Sea with an unusual color. Sometimes color changes like this are indicative of an algal bloom. Given the unusually warm ocean temperatures this summer, algae and, in particular, harmful algal blooms have been a hot topic in Alaska. Much of southern Alaska has been experiencing high to very high levels of paralytic shellfish poisoning in shellfish samples, which has inhibited harvest in some areas. Looking through the LEO data image archive, it appears that the color first occurred in early July. Incidentally, this is the same region where observations of die-offs of seabirds, in particular shearwaters, occurred (see image). The first shearwater observation posted to LEO Network occurred July 22nd in Port Heiden and was followed by observations in Egigik, Togiak, Bethel, Kivalina, and most recently Quinhagak on August 15. I am hoping that someone who is familar with satellite remote sensing of ocean conditions can look at these images, or better ones and determine what the possible causes are. If it is algae, my next question is whether seabirds may be feeding in that area and whether they may have been affected by harmful algae.

Dean Stockwell from the University of Alaska Fairbanks Institute of Marine Science  writes: 

Usually when I see these white-ish patches, they are blooms of coccolithophorids. There was an extensive bloom in the Bering in 1997-1998. I am not aware of any toxic forms. NOAA (National Oceanic and Atmospheric Association) bottom fish survey should be finishing up and heading into Dutch in the next day or two. 8/21/19

Kris Holderied, Director of NOAA Kasitsna Bay Lab, writes: 

From the brightness in the satellite imagery, this looks like a coccolithophore bloom, which has been seen before in the eastern Bering Sea. FYI, I'm attaching one article (free from EOS) from a 1997 bloom event, which also coincided with a shearwater die-off. I'm also copying Phyllis Stebano, who was one of the authors and has lots of expertise in these events, and may be tracking this one. 

The bright colors in the satellite imagery indicate high reflectance and are consistent with what has been seen in past coccolithophore blooms (Emiliania huxleyi) in the Bering Sea. Some events have also occurred at the same time as a seabird die-off (for example with shearwaters in a 1997 Bering Sea bloom). These phytoplankton species do not produce toxins, but can affect other phytoplankton production. 8/21/19

See:

Vance et. al - Aquamarine Waters Recorded for First Time in Eastern Bering Sea

S.I. Zeeman and P. Stabeno - The Continuing Coccolighophore bloom in the Bering Sea

Veronica Lance, Program Scientist with the NOAA CoastWatch, writes:

Taking a quick look at this now with some of our ocean color and true color online viewing tools. I do see a lot of what looks like runoff/sediment plumes in the coastal areas and also what looks to be elevated chlorophyll associated with those (a little bit "downstream" oceanographically speaking of the brown turbid water). We have two "experimental" chlorophyll anomally products that show mixed results, but gives some support to your conclusions of algal blooms. Anecdotally, there seem to be many crazy blooms going on this season all over the place. As a scientist, of course I don't have data to confirm or deny. I can help get you more satellite images and products. Best if someone local could take some water samples to confirm. Note that the satellite data cannot tell us whether a TOXIC bloom is occurring, but they are useful to look at chlorophyll trends over time and space. If someone on the ground can confirm a specific algal species or can measure bio-chemicals in the water, then you will have better evidence to link the blooms with the birds. 8/21/19

Some example links for satellite imagery and for data access for your area of interest are below. As you have already identified the phenomenon, I am not showing you anything new here, but these tools may give you more ease of access to follow into the future and track back into the past, (e.g., 29 July in Pacific or past years like 8 Aug 2014). 8/22/19

True Color from VIIRS SNPP same day. VIIRS is afternoon orbit and has a slightly coarser resolution ~750 m spatial resolution but global coverage is daily for the true color. See image.

Here’s is a polar projection (image) of the area on another day.

(Here is image) 8 August 2014, and click back a few days to see it through more clouds on 5 Aug 2014.

See also: NOAA CoastWatch  

 Hillary Burgess with the Coastal Observation and Seabird Survey Team (COASST) writes: 

Sharing the USGS handout from the die-off from last year. (see attached document entitled, Harmful Algal Bloom Toxins in Alaska Seabirds, 2018.  8-23-19

 

Sarah Schoen comments:

In response to the reports of the shearwater die-off, I went out to Bristol Bay on August 5th and 6th to conduct beach surveys for beachcast birds and collect samples from the food web to test for harmful algal bloom toxins (domoic acid and saxitoxin). I collected multiple sea surface water samples from the Naknek region, near Egelik, north of Cape Grieg, and near Port Heiden. I also collected zooplankton from Naknek, a few blue mussels from near Cape Grieg, two salmon from Naknek, and 9 shearwaters scattered throughout that area. We are very interested to see what our analyses find, and I will be sure to share our results when we have them! 8-30-19

Comments from LEO Editors:

For more information about the ongoing shearwater seabird die-off event, see map developed by Erica Lujan here.