LAKES LINGANORE & ANITA LOUISE STUDY UPDATES Hannah Zinnert - - PowerPoint PPT Presentation

LAKES LINGANORE & ANITA LOUISE STUDY UPDATES

Hannah Zinnert Gabrielle Troutman

LAKE ANITA LOUISE

Gabrielle Troutman

Why Study Lake Anita Louise?

• Last winter, a bloom of toxic

algae, Planktothrix rubescens, turned the lake pink and raised concerns about water health

Planktothrix rubescens

• Species of filamentous cyanobacteria

that may produce microcystin

• Microcystin is a hepatotoxin (a

chemical substance that damages the liver)

• Exposure to hepatotoxins may cause

nausea, vomiting, diarrhea, and in some cases, acute liver failure

• Humans can be exposed through the

mouth and skin while swimming, drinking water, or showering in water that has been contaminated

Lake Anita Louise Study Goals

Is Planktothrix rubescens still present in Lake Anita Louise at excessive levels?

• Determine if P. rubescens is persisting in the lake
• Determine if current levels of microcystin exceed the safe limit set by

the World Health Organization (WHO)

• Consider possible solutions to decreasing the presence of P. rubescens

Study Recap

• Hood’s robotic boat used to map

bathymetry

• Located cold, deep point to sample
• Conducted bi-weekly sampling visits
• Samples tested for: dissolved oxygen, temperature,

conductivity, pH, turbidity, dissolved inorganic phosphorous, chlorophyll, and phycocyanin levels

• Samples examined under microscope to identify

algal species present

• Maryland Department of Environment conducted

toxin analyses and reported microcystin levels

GIS-Generated Bathymetry Map

• Created using Hood’s

robotic boat and GIS software

• Generated to determine

areas where Planktothrix may be persisting

• Sampling location chosen

based on deepest point

The Stratification of Lakes

5 10 15 20 25 5 10 15 20 25 30 Depth (ft) Temperature (°C) 6/10/2016 7/6/2016 8/1/2016

Changes in Temperature

Thermocline

While the surface

• f the lake and

the oxycline warmed over the course of the summer, the bottom of the lake remains a constant temperature of ~8-9°C

For reference…

0°C = 32°F 20°C = 70°F

Continuously cold temperatures indicate that there may be a groundwater-fed spring in the bottom of the lake

Changes in Conductivity

5 10 15 20 25 200 400 600 800 1000 Depth (ft) Conductivity (µs/cm) 6/10/2016 7/6/2016 8/1/2016

• Conductivity has

remained fairly constant at the surface and bottom

• f the lake

throughout the summer

• Freshwater systems

can have a conductivity anywhere between 100-2,000 μs/cm

Higher benthic conductivity may be due to incoming groundwater in the bottom

• f the lake

Ions from spring at bottom

• f the lake are diluted by the

time they reach the surface

Mixing between surface and bottom water is creating variance in conductivity

Changes in Dissolved Oxygen

4 8 12 16 20 24 2 4 6 8 10 12 14 Depth (ft) Dissolved Oxygen (mg/L) 6/28/2016 7/20/2016 8/1/2016

Depleted oxygen Increased oxygen Below this point, the water is hypoxic – this is a harsh environment for organisms that require oxygen Oxycline

• The oxygen available

reduced drastically between June and Jul/Aug.

• The depleted oxygen

zone is indicative of heterotrophic

• rganisms consuming
• xygen, while the

increased oxygen may indicate an algal

• bloom. Algae are

autotrophic and produce oxygen as a product of photosynthesis.

Changes in Turbidity

10 20 30 40 50 60 70 6/29/2016 7/9/2016 7/19/2016 7/29/2016 8/8/2016 Turbidity (NTU) Date Surface Oxycline Max Depth

Spike in turbidity in beginning of August

• Turbidity is a

measure of water

• clarity. The higher

the turbidity, the less clear the water appears.

• Turbidity is

impacted by sediments, algae, and decomposing plant matter.

Changes in ratio of Phycocyanin to Chlorophyll

0.1 0.2 0.3 0.4 0.5 0.6 0.7 5/30 6/9 6/19 6/29 7/9 7/19 7/29 8/8 Ratio of phycocyanin:Chlorophyll Date Surface Oxycline Max Depth

Green algae Blue-green algae

• A high phy:chl ratio is

indicative that the algae is composed mainly of blue-green algaes

• The photo provided

supports that the

• xycline water sample

from the end of June with a high phy:chl ratio was composed of more blue- green algae than other species of algae.

Predominant Algae

June July August

Toxin Analysis Results

Microcystin (ppb) WHO Recommended Limits Drinking Water 1 Accidental Ingestion 2 - 4 Moderate Risk 20 Lake Anita Louise January 352 February 160 March >100 April 32 May 34 June (surface) 1.08 June (max depth) 33.6

Concerns for the Future…

• Planktothrix continues to persist in the lake
• While surface microcystin levels have dropped to near the WHO

limit, levels at the bottom of the lake remain nearly 33x greater than is recommended

• Fall turnover will mix the contents of the lake and winter will

decrease the temperature, creating a perfect environment for Planktothrix to thrive

• Anita Louise feeds into Lake Linganore and could transfer

microcystin

Possible Remediation Action at Lake Anita Louise

• Reduction of nutrient inputs into the lake
• Have your soil tested to find out if fertilizers containing phosphorous are necessary
• Create a buffer zone – don’t mow right up to the edge of the Lake and plant shrubs

along the edge of properties

• Install rain barrels at homes to collect rain water and decrease runoff
• Peroxide application during winter when Planktothrix is at the

surface of the Lake

• Addition of barley straw to the water in the spring to inhibit

growth

• Draining the lake to allow bottom water to receive full sunshine

Any Questions?

LAKE LINGANORE

Hannah Zinnert

Goals

• Is Lake Linganore at risk for harmful algal blooms? If so, what

can be done to improve the health of the lake?

• Investigate multiple water quality parameters over the course of the lake’s growing

season

• Determine predominant algae species found throughout the growing season
• Understand the amount of nutrient flux occurring in the lake and how it interacts with
• ther water quality parameters

What is a harmful algal bloom (HAB)?

• Occur when colonies of algae grow out
• f control while producing toxic or

harmful effects on people, fish, shellfish, marine mammals, and birds

• Microcystis sp.
• A type of freshwater blue-green algae

that can form HABs

• Can produce hepatotoxins
• Liver toxins that can cause nausea,

vomiting, and acute liver failure

Methods

• Bi-weekly sampling at

5 sites on the lake

• Collected vertical

profile data at all 5 sites

• Collected water grab

samples at sites 1,2, & 4

Methods

• Collected multiple water quality

parameters for each vertical profile site

• Including temperature, dissolved
• xygen, light intensity, and

conductivity

• Analyzed water sample grabs at

surface, middle, and max depth

• Chlorophyll and phycocyanin

fluorescence, active chlorophyll a concentrations, pH, and turbidity

Water Quality

• Temperature
• Dissolved

Oxygen

Depth (ft) Temperature (° C)

Site 1 Temperature

17-May 13-Jun 18-Jul

5 10 15 20 25 30 35 5 10 15 20 25 30 35 Depth (ft) Temperature (° C)

Site 4 Temperature

17-May 13-Jun 18-Jul

Thermocline Thermocline

• In the deeper sample site, the increasing temperature trend is the

same

• However, a thermocline is set up by June and gets even larger by

July

• Generally, the water warms from surface to bottom throughout the

summer

• By mid July, a thermocline is set up and the water column is more

stratified

Water Quality

• Temperature
• Dissolved

Oxygen

Depth (ft) DO (ppm)

Site 1 Dissolved Oxygen

1-Jun 18-Jul 3-Aug

Depth (ft) DO (ppm)

Site 4 Dissolved Oxygen

1-Jun 18-Jul 3-Aug

• High levels of DO in surface waters
• DO decreases as you move deeper in the water column
• As summer progresses, the area of the water column containing little to no DO moves higher

Nutrients (MDE 2014 Data)

more water

DIN (mg N/L) Sampling Date

Dissolved Inorganic Nitrogen (DIN)

DIN Surface DIN Bottom

DIP (mg P/L) Sampling Date

Dissolved Inorganic Phosphorus (DIP)

DIP Surface DIP Bottom

• Much higher concentration of Dissolved Inorganic Nitrogen (DIN) than Dissolved Inorganic Phosphorus (DIP)
• Concentrations of DIN in surface and bottom remain elevated throughout the growing season
• Bottom DIP remains elevated (and even increases some), while surface DIP reduces to trace amounts

Nutrients (MDE 2014 Data)

• Phosphorus is released from the sediment in the lake during summer months when the

lake is stratified and there is little oxygen in the bottom

Nutrients (MDE 2014 Data)

DIN/DIP Ratio

12-May 2011:1 23-Jun 1802:1 30-Jul 7973:1 26-Aug 3149:1 15-Sep 1717:1

• For optimal algal growth, only needs to be 16:1
• Therefore, growth is Phosphorus-limited

Chlorophylls & Phycocyanin

Active Chl a Concentration (ug/L) Sampling Date

Active Chl a of Surface Grabs at Site 4

Ratio Sampling Date

• Concentrations of Chl a in the surface spiked in early

June and remained elevated throughout the summer

• By mid July, the phycocyanin:chlorophyll ratio spikes to a

peak, indicating a large increase of blue-green algae

Phycocyanin:Chlorophyll Ratio of Surface Grabs at Site 4

Predominant Algae

Spring Early Summer Mid/Late Summer

Mix of blue-green algae and diatoms Mix of diatoms, dinoflagellates, and green algae Mostly blue-green algae

The Big Picture

• Microcystis sp. has only been found in small quantities in the lake this summer
• This could be due to the number of storms that have occurred over the summer
• However, the conditions of the lake are indicative of large surface algal growth

and are primed for a potential harmful algal bloom

• Not only is the Lake Linganore community in an agriculturally dominated area, but

construction has been occurring and new housing construction will begin soon that can potentially bring in more sediment and nutrients

What actions can be taken?

• Reduce residential fertilizer usage
• Apply low phosphorous fertilizer once a year in the fall if necessary
• Keep vegetation along edges of the lake as a buffer to catch

nutrients

• Continue monitoring phycocyanin fluorescence values for

potential blooms, especially during dredging

• Remain vigilant regarding the use of silt fences during new

construction phase For more information on how you can manage stormwater on your property, please visit:

http://www.mde.state.md.us/programs/Water/StormwaterManagementProgram /Pages/programs/waterprograms/sedimentandstormwater/chesapeake.aspx

Thank you to…

Eric Roberts

• Dr. Drew Ferrier
• Dr. Kevin Sellner

Claire Hudson Susan Simonson Randy Smith

• Dr. George Dimitoglou

Peter O’Connor Andrea Kozlosky Brianna Fragata Abbi Strock Hanne Christensen LLA Volunteers

Frederick County DUSWM

0.5 1 1.5 2 2.5 1 10 100 1000 5/27/16 6/3/16 6/10/16 6/17/16 6/24/16 7/1/16 7/8/16 7/15/16 7/22/16 7/29/16 8/5/16

Daily Precipitation (inches) E Coli Concentration (MPN / 100 mL)

Lake Linganore E. Coli vs Precipitation - 2016

Nightingale Precipitation

459 126 235 MD - Site-specific Daily Max. MD - Generic Daily Max. MD - Max. Avg. Source: LLA / FoL, Water Quality

20 40 60 80 100 120 140 2013 2014 2015 2016

Mean E. Coli (cells / 100 ml)

Average Lake Linganore E. Coli by Year (summer geometric mean)

Mean E. Coli (geometric)

MD Public Beach Standard =

Source: LLA / FoL, Water Quality

5 10 15 20 25 30 2013 2014 2015 2016

# Days Exceeded MD Generic Daily Max

Summer Days E. Coli Exceeded MD Generic Daily Maximum by Year

Days ExceededMD Max Daily (generic)

MD Public Beach Generic Daily Maximum = 235 cells/ 100 ml

Source: LLA / FoL, Water Quality