XuHai and Hans are cookin up some “cyano soup”.
Collected Taihu stations today and was amazed at how buoyant the cyanos (mostly Microcystis) are right now. Within 30 seconds they went from a shaken suspended state to surface scum formation. Have a look.
Hey folks: Here’s some real bloom dynamics at Taihu. No photoshop stuff!! ☺
Within a week here the bloom has gone from bright green N sufficient to N limited, and last year we tested it with a 2- day nutrient addition bioassay, where we were able to make it N sufficient again by adding NO3. All the green Cubitainers received N.
For two and a half decades, ModMon has provided valuable information on water quality and habitat conditions in the Neuse River Estuary and Pamlico Sound. These data are crucial for evaluating how conditions are changing in response to human and climatic pressures. ModMon has also served as a platform to support research projects aimed at figuring out how estuaries work from ecological, geological, physical, and biogeochemical perspectives.
Conditions on 4 June 2019 were pretty typical for this time of year. Salinities ranged from zero above New Bern to a maximum of about 15 in the bottom waters near the mouth. Stratification was not particularly intense except at station 160 which was influenced by saltier bottom water likely from the Intracoastal Waterway. Hypoxic conditions occurred throughout most of the length of the estuary but were confined to a thin, ~1 m thick, layer near the bottom. A zone of high DO, high pH, and high chlorophyll a was observed at station 30 near New Bern. Microscopic examination of surface waters from station 30 revealed a high concentration of cryptophytes that are generally good food for higher trophic levels, and don’t cause problems.
June commemorates the ModMon project, launching 25 years ago.
During the past two and a half decades, ModMon has supported over 80 publications and reports in premier, peer-reviewed journals and books. These publications have had major impacts on research, management and decision-making concerning North Carolinas estuaries.
A bit about ModMon
Malcolm’s proposal is “Understanding the effects of grazing on cyanoHAB toxicity” which involves using a dilution bioassay experiment, to investigate the effects of grazing on microcystin production in the cyanoHABs in Western Lake Erie.
A couple of weeks without rain and the estuary is looking almost normal. The salt wedge is at New Bern and surface water salinity near the mouth was about 10. Most of the estuary was strongly stratified and bottom waters were hypoxic from stations 60 to 160. There was a peak in DO at station 50 that was likely due to high phytoplankton production. Microscopic observation of the station 50 surface sample showed a high concentration of small (3-5 um) centric diatoms. Chlorophyll data are not shown due to a failed probe. During the previous trip on 7 May, the chlorophyll probe of the YSI data sonde started to malfunction but the malfunction was not noticed until this trip on 21 May 2019. The bloom level chlorophyll a concentrations observed at station 50 on 7 were an artifact of this malfunction. The probe has been replaced and in vivo chlorophyll a data from both dates have been flagged in the data set.
A fish kill was observed a few days following this trip on 21 May, but no dead fish were noticed during a boat run from New Bern to station 100 on yesterday, 28 May. Based on the reports that I saw, the dead fish were mostly menhaden and had sores consistent with ulcerative mycosis caused by Aphanomyces invadans. This fungus is most virulent when salinities are low and temperatures are in the low to mid 20’s C; conditions observed during the fish kill. Fish that are already stressed, e.g. due to hypoxia, are more likely to suffer from the infection. I’ve attached a couple good papers for those interested.
Kiryu et al. 2002-induction of menhaden ulcers by exposure
Oidtmann 2011-review of A invandans
New and improved, more compact and portable water quality instruments , built by Tony Whipple of the Leuttich Lab are being installed on the M.V. Neuse, allowing for easier transfer from ferries.
This would not be possible without help from our friends at NCDOT ferry division. David Griffin and John Destefano were instrumental in getting things connected.
The M.V. Neuse, appropriately named, is currently crossing the Neuse River from Cherry Branch to Minnesott Beach.
Stay tuned for updates on the FerryMon Page as to when this system is up and running. https://paerllab.web.unc.edu/projects/ferrymon/
David “Sparky”, John and Tony
The water quality analysis system
The Neuse is an estuary again, a strongly salinity, stratified estuary with hypoxic bottom waters. The hypoxic zone stretched from just downstream of New Bern to the mouth. A zone of high chlorophyll with a subsurface maximum at ~1 m depth was detected from stations 20 to 70. Microscopic examination of surface waters from station 50 revealed a community dominated by freshwater diatoms, primarily Aulacoseira.
Until the next trip,