Is An Algae Bloom Coming … To Creeks Of Whitehall Bay?

Published: May 3, 2021

It’s cold out on the Severn In April!
Yet, our intrepid Water Quality Teams were out braving the weather to get an early start on tracking conditions in the Severn River.

Evidence is mounting in the Creeks of Whitehall Bay that something untoward is developing – the beginnings of an algae bloom like the Mahogany Tide of 2020.

Our WQ Team certain found some disturbing indicators in Mill, Burley, Whitehall, Ridout and Meredith Creeks in April.

Nevertheless, Three cheers to WQ Team Members Emi, Kathryn, Art and Tom on a cold April 16 morning.

We all felt like it was ready to snow.

Despite the cold water, we’re finding a plenty of oxygen (well above 5 mg/L) everywhere.

That’s typical for this time of year.


But why do we believe a harmful algae bloom is again likely?

A few key observations:

  • At the the heads of Mill, Burley and Whitehall Creeks, we found thick patches of filamentous algae (see pic of Capt. Tom hauling anchor),
  • This indicates there’s plenty of junk food (nitrogen) in the water for the algae to feast upon,
  • Poor clarity readings too, Mill Creek Station #3 Secchi reading was 0.76 m and at the head Whitehall Creek at WH Station #3, only a 0.64 m reading,
  • A brown color in the water despite no recent rains (see pic of the Secchi disk at left disappearing way too quickly compared to the 1.30 m Secchi readings were recorded in other creeks last week),
  • A giant brown spot in Whitehall Creek between Ridout Creek and Whitehall Marina (again, with no recent rain, this does not appear to be a sediment plume), and
  • Supersaturated oxygen conditions, especially at the surface of the creeks. We were getting readings of 122.3% as a percentage and 11.86 mg/L for dissolved oxygen.

Prorocentrum Minimum Gorging?

SRA’s Field Investigator Emi explains that the high percentage of dissolved oxygen means there is a “something” creating an overabundance of oxygen in the creek.

Emi suspects that “something” is likely the prorocentrum minimum algae that eventually creates the Mahogany Tide conditions that we saw last May in the Severn River system.

We’ll be keeping a close watch on conditions every week.

It’s thanks to your support of SRA that our WQ teams are able to keep an eye on your river and track conditions. To enable our WQ crew to continue this invaluable work, please considering donating to SRA by clicking here.