Well, summer 2021 has certainly arrived and with the blistering heat sea nettle season is upon us.

But boy, was it cold out on the Severn River back in April when our intrepid Water Quality Monitoring Crew started tracking conditions in the Severn River. 

This is how our Field Investigator, Emi McGeady, WQ Crew Kathryn and Art bundled up in that first week in April. Please give them a hug of thanks when you see then. They’re still shaking off that spring chill!

Which means the monitoring season starts in April and runs through early November. Our teams got started the first week April and the weather was brisk! Winter had returned! Three cheers to our WQ Team for braving the a cold April 16 morning. They all felt like it was ready to snow!

And what they found is chilling – evidence that the Severn River would suffer through another algae bloom.

They found clues in the Creeks of Whitehall Bay all the way up through Round Bay that something untoward is developing – the beginnings of an algae bloom.

They kept a close eye on this bloom to see if it would explode into a full-blown Mahogany Tide like we suffered through in 2020. Fortunately, the this year’s algae bloom hasn’t reached the 2020 level,  but the algae bloom was still formidable.

Our WQ Team found key indicators in Mill, Burley, Whitehall, Ridout and Meredith Creeks from mid-April through late May.

The same clues showed up in Back, Spa, Weems, Luce, Saltworks, Clements and Brewer Creeks.  

Why do we believe that a harmful algae bloom was forming? 

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 0.76m and at head Whitehall Creek 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.

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.

That “something,” Emi explains, is likely the prorocentrum minimum algae that eventually creates the Mahogany Tide conditions that we saw in the Severn River in 2020.

Algae blooms are warnings that the river is being adversely affected by polluted stormwater runoff. The runoff contains nitrogen from many sources, particularly lawn fertilizer runoff in the Spring. 

An overabundance of nitrogen in warming waters and lots of sunlight fuels algae blooms.

These are bad because they block the sun from reaching our underwater grasses and, when the algae die off, their decomposition depletes oxygen from the water, creating dead zones.

The algae also leave ugly scum on the river’s surface (see picture at right).

Our WQ Crews will be keeping a close watch on conditions every week through early November.

It’s thanks to your support of SRA, and a special grant from Delaplaine Foundation, that our WQ teams can keep an eye on your river and track conditions.

To support this invaluable work, please considering donating to SRA by clicking here.