an unexpected benefit from seagrass recovery in tampa bay

K.K. Yates

An Unexpected Benefit from

Seagrass Recovery in Tampa Bay

Kimberly K. Yates, U.S. Geological Survey, St. Petersburg, FL, [email protected]

TAMPA BAY

WATERSHED

FACTS

TAMPA BAY: 400 SQUARE MILES

TAMPA BAY WATERSHED: 2,200 SQUARE MILES

AVERAGE DEPTH: 11 FEET

MAXIMUM DEPTH: 43 FEET

POPULATION IN WATERSHED: 2.7 MILLION (2010 CENSUS)

MAJOR TRIBUTARIES: HILLSBOROUGH, ALAFIA, LITTLE MANATEE AND MANATEE RIVERS

From: TBEP, CHARTING THE COURSE: THE COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN FOR TAMPA BAY (AUGUST 2017 REVISION)


Citizens helped lead the way toward

improving Tampa Bay’s water quality

Tampa Bay on the road to recovery

• More than 500 projects to reduce nitrogen loads by 2016

• Major reductions in nitrogen loads entering Tampa Bay

• Water quality has improved

• Water clarity improved to 1950’s levels

Total Nitrogen Load to Tampa Bay

Image credit: E. Sherwood, TBEP

~1976 1985-1989 1990-1999 2000-2011


Seagrass has been restored to 1950’s levels

Image credit: JOR Johansson Image credit: TBEP

Unexpected benefit = increase in pH

Tampa Bay Seagrass Acreage and pH

Levels

From Sherwood et al., 2016

EPC-HC Water Quality

Monitoring Program

Is Tampa Bay a regionally significant refugia from ocean and coastal acidification processes?

• Eutrophication• Upwelling• Freshwater inflow

Ocean & coastal acidification (OA)

Ocean acidification is driven by elevated atmospheric CO2

Coastal acidification is driven by local & regional processes

• Fossil fuels• Land use• Cement production

Important for shell & skeleton growth

…and will be exacerbated by ocean acidification.

Coastal acidification is already occurring

HI atm. CO2

3 ppm per year= 0.78%/year

Seawater CO2

1.2 to 2.1 ppm per year= ~0.5%/year

Atmospheric CO2 at Mauna Loa Observatory

Ocean Acidification

2006 2007 2008 2009 2010 2011 2012Year

Seawater pCO2

Air pCO2

Linear (Seawater pCO2)Linear (Air pCO2)

Gray’s Reef National

Marine Sanctuary

(Georgia)

2006 to 2013Scott Noakes, UGA

GR atm. CO2


GR seawater CO2


Gray’s Reef Buoy CO2 Data

Coastal Acidification

…including fishery species, especially shellfish.

• Reduces carbonate shell and skeleton

growth rates and can cause them to dissolve

• Filtration rates, immune response & growth

rate of oyster spat

• Increased sensitivity of fish to hypoxia

Acidification affects all species

There are ocean acidification losers… …and winners

• Increases growth rates of seagrasses

and some species of algae

• Increases rates of photosynthesis

Seagrass photosynthesis buffers OA

Hey!

I’m getting the short

end of the shoot

here!!

We prefer our

CO2 in beer!

K.K. Yates

Photosynthesis

consumes CO2,

produces oxygen,

and increases pH Benefits depend on spatial proximity, speed of water flow, and

direction of water flow

Pilot study to inform OA monitoringPotential role of seagrass recovery in buffering Tampa Bay from OA

• May 11 – 22, 2015

• Upper and Lower Bay Thallassia-dominated seagrass beds

• Spatial variability in water chemistry including pH and pCO2 along transects from shallow-dense seagrass, transitional & deep edge seagrass, to bare sand

• Daily variability in water chemistry and consistency; biological, chemical & physical controls

• Appropriate sampling times and constraints

K.K. Yates

CalculatedCarbon Speciation

pCO2

W

Via CO2SYS(Pierrot et al. 2006)

Discrete measurementsSpatial variability

TA, TCO2, pH, T, S, DO, DOC

4 hr intervals for 24 hrsSeagrass productivity

Nutrients (morning, night)

Discrete & autonomous water chemistry

<100 m

K.K. Yate, USGS

ADCP

Water Sample Tubes

Autonomous measurementsOcean Carbon System (OCS)

Daily variability1 hr intervals for ~1 week

pH, pCO2, T, S, DO, PAR

K.K. Yates

Depth ~1m Depth ~2.5 m

7.6

7.8

8.0

8.2

8.4

8.6

Dense Seagrass OCS-t ransit ional Deep Edge Sand

pH

UpperTampaBay

7:30

11:30

15:30

19:30

23:30

3:30

7.6

7.8

8.0

8.2

8.4

8.6


pH

LowerTampaBay

7:30

11:30

15:30

19:30

23:30

3:30

Seagrass can increase pHpH 0.5 higher in dense

seagrass than sand

Spatial variability

amplified by slower currents

(Avg. velocity = 0.02 ms-1)

Spatial variability

Less spatial variability,

faster water currents

(Avg. velocity = 0.1 ms-1)

Slack tide

D = 0.5

D = 0.2

K.K. Yates

Respiration can decrease pHpH 0.2 lower in dense

seagrass than sand

0

1

2

3

4

5

6

7

13:30:04

18:30:04

23:30:04

4:30:04

9:30:04

14:30:04

19:30:04

0:30:04

5:30:04

10:30:04

15:30:04

20:30:04

1:30:04

6:30:04

11:30:04

16:30:04

21:30:04

2:30:04

7:30:04

12:30:04

17:30:04

22:30:04

3:30:04

8:30:04

13:30:04

18:30:04

23:30:04

4:30:04

9:30:04

14:30:04

19:30:04

0:30:04

5:30:04

19:30:06

0:30:06

5:30:04

10:30:06

15:30:07

20:30:06

1:30:13

6:30:13

11:30:13

16:30:13

21:30:13

2:30:13

7:30:13

12:30:13

17:30:13

22:30:13

3:30:13

8:30:13

Ara

go

nit

e s

atu

rati

on

sta

te

0

50

100

150

200

250

300

350

400

450

500

DO

(m

M)

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

8.4

8.5

pH

OCS Discret e

Upper Tampa Bay Lower Tampa Bay

0

200

400

600

800

1000

1200

pC

O2 (

matm

)OCS Calculat ed discret e

Large amplitude

diurnal signatures

Minimums &

maximums occur

consistently in

early AM

(5:30 – 7:30)

or early PM

(16:30-19:30)

Strong control from

photosynthesis &

respiration

Daily variability

K.K. Yates

May 11-17 May 18-22

Pilot-study lessons learned

• Seagrass beds can locally increase pH and decrease CO2, but can also do the opposite.

• Daily variability is relatively predictable, but can be affected by water currents.

K.K. Yates

• Whats the balance of increases and decreases in pH and CO2 locally and bay-wide?

• Is seagrass only providing local benefits or affecting water chemistry bay-wide?

• WE CAN MONITOR WATER CHEMISTRY TO ANSWER THESE QUESTIONS.

Implementation of OA monitoring

Partnership with USF College of Marine Science and Center for Ocean Technology

• Provides meteorological and current data along with water chemistry

• Allows for measurement of bay effects on water chemistry

• Saves ~$500K in monitoring platform costs

• Funded by TBERF, TBEP, EPA Region 4

USF COMPS C12 buoy

Ocean Carbon System

Gulf of Mexico

Ocean Carbon System Tampa Bay

~60 miles offshore

USF PORTS station

Tampa Bay Ocean Carbon Systems (OCS)

~1 to 2 m depth

Hourly sampling

Solar panel

Rechargeable battery

Cellular telemetry

Water pump

Data logger

Measure

pH

Salinity

Temperature

Dissolved oxygen

PAR

pCO2

OCS systems

Tampa Bay

Ocean Carbon System

Gulf of Mexico

Ocean Carbon System Tampa Bay

Image credit: Sean Beckwith

Image credit: Chris Moore

Real-time data available onlinehttp://tampabay.loboviz.com/A

va

ila

ble

me

as

ur

em

en

ts

http://tampabay.loboviz.com/

LOBOViz CO2 example plotDec. 15, 2017 to March 19, 2018

Biofouling of intake pump for CO2 began

March 7 and was corrected on March 19

Remove bad data from

public graphs

Real-time data available onlinehttp://comps.marine.usf.edu/index?view=station&id=C12

Next steps…exploring the data

Evidence for tidal control on daily

time scale

Evidence for temperature control

over weekly to monthly time scale

CO

2(p

pm

)

CO

2(p

pm

)

Pre

ssu

re (

db

ars)

Pre

ssu

re (

db

ars)

Tem

per

atu

re (

C)

pH

T

pH

T

Tem

per

atu

re (

C)

3 month record

3 month record

MORE RESULTS

COMING SOON!

Many thanks to…

Holly Greening, Ed Sherwood, Gary Raulerson (TBEP)

Ryan Moyer, Christina Powell, Amanda Chappel, Iona Bociu (FWRI)

Dave Tomasko, ESA

Mark Luther, Bob Weisberg, Jason Law, Randy Russell, Jeff Donovan (USF)

Brian Rappoli, Amanda Santoni (EPA)

Chris Moore, Nathan Smiley, Legna Torres-Garcia, Mitch Lemon (USGS)

Funding sources: TBEP, EPA Region 4, TBERF, USGSOctober 26, 2018 deployment


…and the many citizens who have helped

improve Tampa Bay water quality for decades!

Orange = no water

quality targets met

Blue = one of the

water quality

targets not met

Green = both water

quality targets met

NUTRIENTS (NITROGEN)

REDUCED BY:

• MORE THAN 500 PROJECTS BY 2016

• Treating stormwater

• Reducing atmospheric deposition

• Upgrading manufacturing processes

• Reducing agricultural contributions

• Reusing wastewater

• Reducing fertilizer use

1978

2016

2006


Water clarity improved to 1950’s levels…

0

50

100

150

200

250

DO

(%

satu

rati

on

)UpperTampaBay LowerTampaBay

7:30

11:30

15:30

19:30

23:30

3:30

0

200

400

600

800

1000

1200

1400


pC

O2 (

ma

tm)


7:30

11:30

15:30

19:30

23:30

3:30

Upper Tampa Bay Lower Tampa Bay

Spatial variability

Slack tide

Slack tide

Higher DO

Lower pCO2

Less spatial

Heterogeneity

2.0 g C m-2 day-1 2.5 g C m-2 day-1

D = 107 D = 52

D = 580 D = 594

K.K. Yates

an unexpected benefit from seagrass recovery in tampa bay

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