freshwater inflows in galveston bay: primary productivity ......freshwater inflows in galveston bay:...

Freshwater inflows in Freshwater inflows in Galveston Bay: Primary Galveston Bay: Primary productivity as an indicator productivity as an indicator of ecosystem functionof ecosystem function..

Dr. Antonietta Quigg, Dr. Antonietta Quigg, Departments Marine Biology & Departments Marine Biology & Oceanography, Oceanography, Texas A&M University at GalvestonTexas A&M University at Galveston

Acknowledgements:Acknowledgements:- co-PI’s – below

- numerous graduate & undergraduate students & technicians especially Leslie, Tyra, Amanda, Allison, Sam and Andrew

Dan RoelkeSteve Davis

State of the Bay State of the Bay –– January 2009January 2009

Freshwater inflows in Galveston BayFreshwater inflows in Galveston Bay

• An examination of the impacts of changes in freshwater inflow and bay circulation are priority areas for state agencies in Texas, particularly given increasing population density

– An additional 3.5 million people predicted to arrive by 2040 in Texas, most of these will reside in coastal areas


• With this rapidly expanding population, coastal municipalities, water regulators and managers are faced with the challenge of meeting human needs, potentially by freshwater diversions, while maintaining critical freshwater inflows to estuaries.




• Beneficial freshwater inflowsare those necessary for salinity, nutrient and sediment loading regimes adequate to maintain the productivity of economically important and ecologically characteristic species in Galveston Bay.


Phytoplankton:– are at the base of the food web– are sensitive to changes in water quality on short

time scales– exhibit seasonal cycles which are related to changes

in water temperature and salinity

– form blooms, which may be harmful either as a result of toxins produced or the accumulation of organic matter



• Presenting findings of a year long monitoring program

-- January to November 2006 January to November 2006 ––that specifically examined changes in water quality, primary productivity and phytoplankton community structure in response to freshwater inflows in the Galveston Bay estuary.

• New program started February 2008 is ongoing…..


Freshwater inflows to Galveston BayFreshwater inflows to Galveston Bay 2006 2006 -- Trinity River dischargeTrinity River discharge

Daily Discharge in Trinity River USGS 08066500

05

101520253035

Jan-

06

Feb-

06

Mar

-06

Apr

-06

May

-06

Jun-

06

Jul-0

6

Aug

-06

Sep

-06

Oct

-06

Nov

-06

Dec

-06

Dai

ly d

isch

arge

(ft3 p

er s

ec; i

n th

ousa

nds)

♦

= sampling trips


Freshwater inflows Freshwater inflows in Galveston Bayin Galveston Bay

DataflowDataflow

Dataflow Dataflow –– mapping Galveston Baymapping Galveston Bay

• water quality and hydrology were measured using a high-speed, flow- through system developed for mapping physico-chemical parameters in shallow aquatic systems in a boat running closely grided transects

• used to concurrently measure water temperature, conductivity, salinity, water clarity (beam transmittance), chlorophyll a (in situ fluorescence), dissolved organic matter (DOM; in situ fluorescence), and PAR

• an integrated GPS is used to simultaneously plot sample positions, allowing geo-referencing of all measurements for each variable.


DataflowDataflow


January 2006 January 2006 -- Galveston BayGalveston Bay


http://wfsc.tamu.edu/davislab/assets/GB/2006-01/GB_chla_Jan06_Filtered.jpg

Temperature (Temperature (°°C)C)

Salinity (Salinity (psupsu))

In vivoIn vivo chlorophyll chlorophyll aa ((ugug LL--11))

Dissolved Organic Matter (Dissolved Organic Matter (ugug LL--11))

Transparency (%)Transparency (%)

Phytoplankton responses Phytoplankton responses to freshwater inflows to freshwater inflows in Galveston Bayin Galveston Bay

Phytoplankton Phytoplankton AnalyzerAnalyzer(PHYTO(PHYTO--PAM)PAM)

PhytoPhyto--PAMPAM

•• Phytoplankton Phytoplankton -- Pulse Amplitude Pulse Amplitude Modulated Modulated (PHYTO(PHYTO--PAM)PAM) FluorescenceFluorescence AnalyzerAnalyzer

• used to concurrently to map health, phytoplankton community composition & primary production

• samples were collected from 41 fixed stations throughout the bay complex, which included 6 discrete stations

• examined in the laboratory within 24 hrs


• BiomassBiomass

•• YieldYield

(potential)(potential)

•• ProductionProduction

CyanobacteriaCyanobacteria

• BiomassBiomass

•• YieldYield

(potential)(potential)

•• ProductionProduction

Diatoms & Diatoms & DinoflagellatesDinoflagellates

Annual changes in Phytoplankton Annual changes in Phytoplankton Community CompositionCommunity Composition


Discrete Discrete measurementsmeasurements

Discrete measurementsDiscrete measurements

• at 6 fixed stations6 fixed stations spaced thru Galveston Bay,

• experiments & measurements included:

• Primary productivityPrimary productivity

• Phytoplankton community compositionPhytoplankton community composition

• NutrientsNutrients• salinity, DOM, many more …


Discrete Discrete stations ( ):stations ( ):

HoustonHouston

Trinity RiverTrinity RiverTrinity Trinity BayBay

GalvestonGalvestonBayBay East BayEast Bay

West BayWest Bay

22

66

55

4433

11

Monthly Monthly gross primary productiongross primary production rates rates ((gCgC mm--2 d2 d--1) measured in Galveston Bay 1) measured in Galveston Bay

during 2006 at 6 fixed stations.during 2006 at 6 fixed stations.

-0.50.00.51.01.52.02.53.03.5

J F M A M J J A S O N D

-95.10 -95.00 -94.90 -94.80 -94.70 -94.60 -94.50

Longitude (oW)

29.20

29.30

29.40

29.50

29.60

29.70

29.80

Latit

ude

(oN

)

ST. 1

ST. 2

ST. 3ST. 4

ST. 5

ST. 6

Gulf of Mexico

Galveston

Pasadena

West Bay

Bolivar Peninsula

Texas City

Trinity River

Houston

22

5544

66

33

11

-0.50.00.51.01.52.02.53.03.5


-0.50.00.51.01.52.02.53.03.5

J F M A M J J A S O N D-0.50.00.51.01.52.02.53.03.5


-0.50.00.51.01.52.02.53.03.5

J F M A M J J A S O N D-0.50.00.51.01.52.02.53.03.5


11

3344

6655

22

Phytoplankton community compositionPhytoplankton community composition in June 2006 at 6 fixed stations in in June 2006 at 6 fixed stations in

Galveston Bay.Galveston Bay.

-95.10 -95.00 -94.90 -94.80 -94.70 -94.60 -94.50

Longitude (oW)

29.20

29.30

29.40

29.50

29.60

29.70

29.80

Latit

ude

(oN

)

ST. 1

ST. 2

ST. 3ST. 4

ST. 5

ST. 6

Gulf of Mexico

Galveston

Pasadena

West Bay

Bolivar Peninsula

Texas City

Trinity River

Houston

22

5544

66

33

11

01234567

Cy Ch Pr Di Cr Ba01234567

Cy Ch Pr Di Cr Ba

01234567


Cy Ch Pr Di Cr Ba

01234567


Cy Ch Pr Di Cr Ba

11

3344

6655

22


•• DataflowDataflow•• PHYTOPHYTO--PAMPAM•• Discrete measurementsDiscrete measurements


Next steps Next steps ……• multivariate multidimensional statistics will be used to determine which factor(s) are most important in driving changes in primary production and phytoplankton community composition

• long term annual studies to compare effect of high and low freshwater inflow years

• long term studies to examine effect of magnitude, pulse and duration of freshwater inflow in downstream processes



Longer term goals Longer term goals ……• develop process-based understanding of the linkages between the magnitude of freshwater inflows, sediment and nutrient loading on productivity for the Galveston Bay ecosystem

• work with circulation models to define how changes in freshwater inflows will affect discrete components of the bay



Longer term goals Longer term goals ……• continue mapping water quality parameters in Galveston Bay to:

- examine how the bay responds to perturbations such as hurricanes, and

- examine bay responses to change flows, for examples, shifts in flow regimes between the Trinity and San Jacinto rivers


Thank you for your attentionThank you for your attention

Questions ???Questions ???



• Findings of the research will be used to:

• assess the importance of freshwater inflow events on water column processes and the downstream ecological impacts of changes to freshwater inflows on the productivity of the Galveston Bay estuary

• develop intense process-based understanding of the linkages between the magnitude of freshwater inflows, sediment and nutrient loading on productivity for the Galveston Bay ecosystem


PhytoPhyto--PAMPAM phytoplankton community phytoplankton community compositioncomposition

• Distinguishes between 3 major taxonomic groups:470 nm 470 nm –– green algaegreen algae520 nm 520 nm –– diatoms & diatoms &

dinoflagellatesdinoflagellates645 nm 645 nm –– cyanobacteriacyanobacteria

• Measures total signal665 nm 665 nm –– chlorophyll chlorophyll aa


CyanobacteriaDiatoms and dinoflagellatesGreen algae

Phytoplankton community compositionPhytoplankton community composition

Offatt's Bayou

Rollover Pass

Christmas Bay

West bay

Texas City Dike Smith Point

Houston Ship Channel Trinity Bay

Summer 2006

PhytoPhyto--PAMPAM healthhealth

• Measures variable fluorescence in photosynthetic organisms

• Use this as a proxy for the physiological status of phytoplankton, and so, primary production

• Fv/Fm = 0.65 ☺• Fv/Fm < 0.4

• Fv/Fm 0.4 > & < 0.65stressed


Station 1

0.00

0.15

0.30

0.45

0.60

0.75

Jan-06 Mar-06 May-06 Jul-06

Month

Fv /

Fm

Station 2

0.00

0.15

0.30

0.45

0.60

0.75


Month

Fv /

Fm

Station 3

0.00

0.15

0.30

0.45

0.60

0.75


Month

Fv /

Fm

Station 4

0.00

0.15

0.30

0.45

0.60

0.75


Month

Fv /

Fm

Station 5

0.00

0.15

0.30

0.45

0.60

0.75


Month

Fv /

Fm

Station 6

0.00

0.15

0.30

0.45

0.60

0.75


Month

Fv /

Fm

☺

Fv/Fm Fv/Fm -- 0.4 > & < 0.650.4 > & < 0.65-- stressedstressed

Fv/Fm Fv/Fm ☺☺

-- rarelyrarelyFv/Fm Fv/Fm -- occasionally, seasonal, spatialoccasionally, seasonal, spatial

☺

☺☺

☺☺

- concurrent concurrent study revealed study revealed phytoplankton phytoplankton are nutrient (N) are nutrient (N) stressedstressed

Monthly Monthly nitrite plus nitratenitrite plus nitrate ((mMmM; blue) & ; blue) & orthophosphateorthophosphate ((mMmM; orange) measured in ; orange) measured in

Galveston Bay during 2006 at 6 fixed stations.Galveston Bay during 2006 at 6 fixed stations.

02

468

1012


-95.10 -95.00 -94.90 -94.80 -94.70 -94.60 -94.50

Longitude (oW)

29.20

29.30

29.40

29.50

29.60

29.70

29.80

Latit

ude

(oN

)

ST. 1

ST. 2

ST. 3ST. 4

ST. 5

ST. 6

Gulf of Mexico

Galveston

Pasadena

West Bay

Bolivar Peninsula

Texas City

Trinity River

Houston

22

5544

66

33

11

02

468

1012


02

46

810

12


0

24

6

810

12

J F M A M J J A S O N D0

15

30

45

60


0

15

30

45

60


11

3344

6655

22

freshwater inflows in galveston bay: primary productivity ......freshwater inflows in galveston bay:...

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