Here is the first set of UD Citizen Monitoring Program Reports for 2015 covering April and May. Subsequent reports will be issued every 2 or 3 weeks during summer, and the reports will be archived at the following web site:
Spring arrived a bit late this year. Temperatures were below normal in early April, but have been about normal since then. Precipitation was normal in April, but May has been rather dry.
As usual, Low Dissolved Oxygen readings (< 4 ppm) began to be detected in upper tributaries and residential canals in May. There was one severely low reading (< 2 ppm) at the Prime Hook boat ramp in late May.
Minor accumulations of Nuisance Aquatic Vegetation were widespread, and major accumulations were observed in the South Bethany canals. I also received reports of large mats of floating algae in other locations including Love creek, Arnell creek, White creek and the Salt Pond. Most of this alga appeared to be Enteromorpha sp., a filamentous green alga, and it appears that it is more widespread than usual this year.
Total Enterococcus bacteria levels were elevated at many sites in late May but did not appear to be associated with rain events. TE levels were generally lower than normal in late April and early May. Remember that bacteria values can be highly variable, so the geometric mean is a better indicator of general conditions than individual samples.
Harmful Algae blooms of a few potentially toxic species most commonly see in the spring appeared in May. Dinophysis acuminata was consistently seen in Torquay canal and sporadically seen in other locations. Generally, this dinoflagellate is of concern at low cell densities because of the potential for toxin to bioaccumulate in shellfish tissue. Fortunately, it does not appear to produce as much toxin in the mid-Atlantic region as in other locations. Research is ongoing to better understand what the risks are here. Dense, visible, blooms of Prorocentrum minimum and Heterosigma akashiwo were observed in 2 different canals. Both species were also commonly seen at lower cell densities in many locations. Both have been shown to cause detrimental effects to aquatic organisms at high cell densities.
Follow the link below to see maps of dissolved oxygen readings taken from shoreline sites for the first 4 weeks of the season.