Full profile (0-1000m) below \/, surface to 400 meters above /\
Seaglider 157 recently completed it's first complete onshore to offshore section, and the data are fantastic! As you saw in the profiles, the oxycline is consistently very near the surface, ranging from 30 to 75 meters depth. Becasue the oxycline is so shallow, we often observe a second chlorophyll peak within hypoxic waters (oxygen below 20 umol/kg or 1 mL/L). We also see consistently elevated backscattering signals throughout the OMZ, from the oxycline to about 300 meters depth. We hypothesize that this signal is at least partially derived (if not mostly) from enhanced microbial activity in the OMZ, and look forward to ship-based sampling to test this idea. We have observed these same features in data from Apex profiling floats that were released in the area last March (Whitmire et. al.,
in prep.;
link to data,
link to plot).
Full profile (0-1000m) below \/, surface to 400 meters above /\
Seaglider 157 recently completed it's first complete onshore to offshore section, and the data are fantastic! As you saw in the profiles, the oxycline is consistently very near the surface, ranging from 30 to 75 meters depth. Becasue the oxycline is so shallow, we often observe a second chlorophyll peak within hypoxic waters (oxygen below 20 umol/kg or 1 mL/L). We also see consistently elevated backscattering signals throughout the OMZ, from the oxycline to about 300 meters depth. We hypothesize that this signal is at least partially derived (if not mostly) from enhanced microbial activity in the OMZ, and look forward to ship-based sampling to test this idea. We have observed these same features in data from Apex profiling floats that were released in the area last March (Whitmire et. al., in prep.; link to data, link to plot).
Amanda,
ReplyDeleteThese are great! You can also see some intrusion-like features in the chl, backscatter and DO, similar to features we've seen off Oregon, but on a grander scale.
Thanks Kipp! OMG - there is so much going on in these data that I hardly know where to start. I am bowled over! That shallow intrusion of low O2 water near the coast - high in Chl, high in bb - is totally interesting. And, the patchiness in the bb is fascinating. AND, what's up with the base of the OMZ? No one has ever seen this OMZ in this kind of detail (as far as I know). It is totally and completely fascinating!
ReplyDeleteAnother interesting feature is the apparent correlation between the breaks in bb in the OMZ and the deepening of the 0.1 ml L-1 oxygen levels. Although it is difficult to see to what extent the oxygen concentrations vary along the cross-shelf in the 150-300m depth range, the bb suggests that there may be some 'undetectable' changes in O2 that propagate across the full depth of the OMZ at 70.6, 71.0 and 71.2W.
ReplyDeleteAnother interesting feature is the apparent correlation between the breaks in bb in the OMZ and the deepening of the 0.1 ml L-1 oxygen levels. Although it is difficult to see to what extent the oxygen concentrations vary along the cross-shelf in the 150-300m depth range, the bb suggests that there may be some 'undetectable' changes in O2 that propagate across the full depth of the OMZ at 70.6, 71.0 and 71.2W.
ReplyDelete