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Tidal Marshes of Barnegat Bay: Nutrient History and Ecosystem Services

Dr. David Velinsky

Patrick Center for Environmental ResearchThe Academy of Natural Sciences of Drexel University &

Department Head, Biodiversity Earth and Environmental Science

December 2016

Tracy Quirk2,  Chris Sommerfield3, Jeff Cornwell4, Ashley Smyth5

and Mike Owens42Department of Oceanography and Coastal Sciences, Louisiana State University3School of Marine Science & Policy, University of Delaware4Center for Environmental Science, University of Maryland‐Horn Point5presently at Kansas Biological Survey, University of Kansas 

Collaborators:

Drs. Marina Potopova and Elizabeth Watson both at Academy of 

Natural Sciences and Drexel University; Dept. of Biodiversity, Earth and Environmental Science

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Outline

• Climate and Coastal Wetlands• Tidal wetlands of Barnegat Bay• Processes in tidal wetlands• Sediment history and burial• Denitrification in wetlands• Mass Balance• Summary

Wetlands Research at the Academy of Natural Sciences

1965 ‐ Dr. Ruth Patrick in 1965 showed that wetlands can remove nutrients and looked at the extent of wetlands in the Delaware Estuary

1996 – Dr. David Velinsky revisited earlier study and modeled oxygen dynamics in Delaware Estuary: tidal freshwater region

1998‐2002 – Dr. Jeff Ashley explored how PCBs and other contaminants cycle in a urban tidal marsh and accumulate in fish tissue

2007‐2012 – Drs. David Velinsky and Jeff Ashley studied the sediment accumulation of chemical contaminants, nutrients and ecological indicators such as diatoms throughout the Delaware and Barnegat Bays

2011‐2014+ – Drs. Tracy Quirk and David Velinsky are investigating the factors that maintain marsh elevation (MACWA)

2011‐2016 ‐ Drs. David Velinsky and Tracy Quirk explored ecosystem services of tidal wetlands in tidal freshwater wetlands of DE and marshes in Barnegat Bay

2014 ‐ Present Dr. Beth Watson continues to study marsh function in Delaware and Barnegat Bays (MACWA and Carbon Sequestration)

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Tidal Marshes: Questions

• Ecosystem Services– “Nutrient, contaminants and carbon cycling and storage in marshes along an estuarine salinity gradient”

• Climate Change– “Response of marshes to sea‐level rise and salt‐water intrusion”

• Land Use Change– “Changing sediments inputs: An unfortunate convergence for tidal marshes”

Ecosystem Productivity

0 200 400 600 800 1000 1200 1400

Swamps and Marshes

Tropical Rain Forest

Estuaries

Temperate Forest

Coniferous Forest

Savanna

Agricultural Land

Woodland and Shrubland

Grassland

Lakes and Streams

Contiental Shelf

Open Ocean

Tundra

Desert Scrub

Extreme Desert

Average Net Primary Productivity (g C m-2 yr-1)

Total area in US =  1.6 x 1011 m2 (loss is about 0.003 X 1011 m2/yr)

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Marsh Response to Sea Level Rise and Sediment Availability

Wetland accretion and erosion

• Local accretion = mass accumulation ÷ soil bulk densitycm/y                       g/cm2/y                       g/cm3

• Absolute accretion = local accretion + subsidence

Accretion

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Delaware Bay2.8 – 4.1 mm yr‐1

mm per year

SLRDs for 60-yr time series at gauge locations across North America

Sallenger, A.H. et al. 2012; Nature Climate Change

Consequences of Coastal Shoreline Development and Marsh Removal

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Salt‐Water Intrusion

River

Ocean

ChangingPrecipitation & 

Evapotranspiration

RisingSea Level

Tidal Fresh

Oligohaline

Mesohaline

Generalized schematic of nitrogen and phosphorus

cycling in wetlands

• Plants and microbial activity are a key component of N and P transformations

• In marine sediments, high levels of sulfide from sulfate reduction, bind Fe and allow for greater release of dissolved P

• Result in the potential alteration of the amount of N and P buried relative to loadings (unlike PCBs or some trace metals)

With salt‐water intrusion

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Philadelphia

2.8 mm/yr

Sandy Hook, NJ

3.9 mm/yr

4.0 mm/yr3.2 mm/yr

Atlantic City, NJLewes, DE

Causes for concern

1. ALTERED LANDSCAPE

‐ Coastal development

‐ Altered sediment load

‐ Increased nutrient load

‐ Direct human alterations

2. RELATIVE SEA LEVEL RISE

‐ Salinity, tide range increase

• Water quality improvement

(e.g. chemical transformation)

• Floodwater retention and protection

• Biodiversity islands and corridors

• Carbon, nitrogen, phosphorus

(i.e., chemical) sequestration

• Locations for human relaxation and nature observation/education

Wetlands provide valuable ecosystem services!

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1. Evaluate permanent nitrogen (N) removal services provided by Barnegat Bay coastal wetlands:

• Sediment burial of nitrogen, carbon and phosphorus (Yr 0)

• Bay‐wide seasonal denitrification rates in salt marshes (Yr 1)

• Mosquito control (OMWM) ponds impact on denitrification (Yr 2)• How do OMWMs impact ecosystem services?

2. Combine data to obtain an overall estimate of N removal services provided by Barnegat Bay wetlands.

Objectives of  Projects:

NJDEP Barnegat Bay Comprehensive Research

Q: What are the fates of nitrogen and other nutrients in the Bay?

Wetlands of Barnegat Bay

Areal Extent: 26,900 acres

Saline Wetlands: 21,800 acres

Tidal Freshwater: 5,100 acres

Data from V. Depaul (USGS)

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Barnegat Bay 

Symptoms of Eutrophication• phytoplankton and macroalgae blooms• brown tide and HABs• alteration of benthic communities• loss of seagrass and shellfish beds

Watershed N load:  4.6 to 8.6 x 105 kg N yr‐1(from 1998 to 2011; Baker et al. 2014) 

TN Load = ~ 5 - 9 X105 kg N/yr

Sources34% > Direct Atmospheric Dep.12% > Groundwater Discharge54% > Surface Water

(Hunchak-Kariouk and Nicholson, 2001)

Load is estimated to be 5X above“background” (Kennish et. al. 2007).Rutgers

Univ., CRSSA

Barnegat Bay

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NJ DEP Monitoring Data

Taken from H. Pang (NJ DEP)

Nitrogen and Phosporus NJ DEP Monitoring Data

Taken from H. Pang (NJ DEP)

Total NDissolved N

AmmoniaTotal PDissolved P

Ortho ‐P

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OO

SEDIMENT

WATER

Organic N ONH4+

Net Ammonification

N2 (g) flux

ON2 (g)

Denitrification

NO3‐ flux

ONO3‐

Net Nitrification

NH4+ flux

Wetland Nitrogen Cycle

Plant uptakeAlgae and Spartina

NO3‐+ NH4

++ DON

Tidal Exchange

Burial

Watershed N&P Loadings

•Taken from Lathrop and Haag (2007)

• Three core locations: upper, mid, and lower reaches. Two cores at each location.

• Sampling in Spring/Summer of 2009-13

• More development• Higher Runoff• Higher Nutrient Conc.• Lower Salinities

• Less development• Lower Runoff • Lower Nutrient Conc.• Higher Salinities

Sampling Program

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How can environmental changes in Barnegat Bay and other areas be monitored over time?

Are management programs succeeding in cleaning up the Bay? 

Questions

Sediment Cores: An ecosystem’s memory

land‐use pollen, stable isotopes (SI), metals

aquatic ecology diatoms, shells, SI, CNP, Fe‐S

pollution sources chemicals (phosphorus, lead, DDT)

Changes related to: Are reflected by changes in:

Importance: climate change, pollution control strategies, response time for change…

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Paleo-environmentaldata

Model versus HistoricalComparisons

Observed PastChanges

Core Analysis

Process-basedmodels

Forecast

Hindcast

Simulate FutureChanges

Simulate PastChanges

?How sediment core data can be used in environmental models…..

Sediments: an ecosystem’s memory

1950

Dep

th f

rom

Sed

imen

t S

urf

ace

Chemical-SedimentSediment

Sediment surface slowly builds up,burying chemicals/indicators with newer

sediment2010

1950

Higher Loads >>

< Lower Loads

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Sampling Locations

• Reedy Creek (BB-1)• Mid Bay-Wire Pond (BB-2)• Oyster Creek (BB-3)

- discharge canal• West Creek (BB-4)

Analytical Parameters

– Organic Carbon, Total Nitrogen and Total Phosphorus

– Diatom Species Composition

– Stable Isotopes of Carbon (13C) and Nitrogen (15N)

– Grain size (< 63 m; clay+silt)

– Radioactive Isotopes: 210Pb and 137Cs

Upper Bay 2002 (BB-1)

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Upper Bay 1930 (BB-1)

Middle Bay 2002 (BB-2)

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Middle Bay 1930 (BB-2)

Lower Bay (BB-4)

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Lower Bay 1930 (BB-4)

Push-Piston Core: One of many methods for taking a marsh core

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Sedimentation rates: 210Pb and 137Cs analysis

210Pb sediment cycling

• 137Cs: atomic weapons or power plants

• Onset and peak are used to mark age-depth

• Assume linear rates between dates

• Particle-reactive; can desorb in marine waters

Half life = 22.5 yrs~ 150 yrs

Cs-137 Fallout at New York City 1954-1990

Year

1950 1960 1970 1980 1990

mC

i / k

m2

0

1

2

3

4

Onset

PeakUS EPA, EML (NYC)

• Particle-reactive

• Pb dating: 100 to 150 yrs

• Supported 210Pb produced by radioactive decay within sediments

• Unsupported 210Pb transported to water from watershed runoff

xsPb-210 (dpm/g)

0.01 0.1 1 10

Dep

th in

cor

e (c

m)

0

5

10

15

20

25

30

35

Core BB1BCs-137 (dpm/g)

0 2 4 6 8 10

r2=0.81

"1964"

Calendar year

1875 1900 1925 1950 1975 2000

CIC modelCRS model

Profiles of excess 210Pb and 137Cs activity for core BB-1

Note: Pb ages based on the CIC model

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Core BB2ACs-137 (dpm/g)

0 2 4 6 8 10

"1964"

Calendar year

1875 1900 1925 1950 1975 2000

CIC modelCRS model

xsPb-210 (dpm/g)

0.01 0.1 1 10

Dep

th in

cor

e (c

m)

0

5

10

15

20

25

30

35

r2=0.94

Profiles of excess 210Pb and 137Cs activity for core BB-2

Note: Pb ages based on the CIC model

Tidal fresh and salt marsh accretion rates in Delaware Estuary:

All SitesMean   0.72 ± 0.21 cm/yr, n=29

Max     1.1 cm/yr

Min      0.39 cm/yr

Salt MarshesMean 0.65 ± 0.17 cm/yr, n=17

Max 1.0 cm/yr

Min 0.39 cm/yr

Tidal Freshwater MarshesMean 0.85 ± 0.24 cm/yr, n=12

Max 1.1 cm/yr

Min 0.60 cm/yr

Barnegat Bay Sites:

All SitesMean   0.25 ± 0.06 cm/yr, n= 4

Max     0.29 cm/yr

Min      0.16 cm/yr

Comparison between Delaware and Barnegat Bays: Accretion Rates

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Total Organic Carbon (%)

0 10 20 30 40

Dep

th (

cm)

0

20

40

60

80

100

0 10 20 30 40 0 10 20 30 40 0 10 20 30 40

TN-Sediments (%)

0.0 0.5 1.0 1.5

Sed

imen

t D

epth

(cm

)

0

20

40

60

80

100

0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5

Sediment Phosphorus (%)

0.0 0.1 0.2 0.30.0 0.1 0.2 0.3

Sed

imen

t D

epth

(cm

)

0

20

40

60

80

100

0.0 0.1 0.2 0.3 0.0 0.1 0.2 0.3 0.4

Distribution of CNP with Depth

• Robust levels of CNP in BB marsh sediments

• Generally higher concentrations in the upper sections, with more constant levels at depth

• Very high P level observed at the surface of BB-4

• The C to N ratio is fairly constant in the upper 40 cm, except for Core BB-2

BB-1 BB-2 BB-3 BB-4

C to N ratio (molar)

0 10 20 30 40 50

Dep

th (

cm)

0

20

40

60

80

100

0 10 20 30 40 50 0 10 20 30 40 50 0 10 20 30 40 50

BB-1 BB-2 BB-3 BB-4

0 2 40 2 40 2 40 2 4

Se

dim

en

t D

epth

(cm

)

0

20

40

60

80

100

15N-Sediment (‰)

-30 -25 -20 -15

13C-Sediment (%)

-30 -25 -20 -15

Se

dim

ent

De

pth

(cm

)

0

20

40

60

80

100

BB-1 Mantoloking

-30 -25 -20 -15 -30 -25 -20 -15

BB-2 Mid-Bay

BB-3 Oyster Creek

BB-4 Parkertown

Stable Isotopes of C and N:Indicators of sources and cycling

• Spartina sp are C4 plants and would yield 13C of OC at ~ -15 to -12 ‰

• Terrestrial plants in this area, as well as algae, are C3 plants and would yield 13C of OC at ~ -30 to - 18 ‰ (algae are more enriched in 13C)

• The 15N of TN can reflect biogeochemical processes (e.g., denitrification) as well as changes in sources to the bay.

X = [(Rsample/Rstd) – 1] X 1000 (‰)

where is X is either 13C or 15N andRsample = 13C/12C or 15N/14N

BB-1 BB-2 BB-3 BB-4

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0.0

0.5

1.0

1.5

Se

dim

en

t 1

5N

(‰

)

0

2

4

6

Col 6 vs Col 11 Col 6 vs Col 9

0.0

0.5

1.0

1.5

0

2

4

6

BB-2

BB-1

Year

1800 1850 1900 1950 2000

To

tal S

edim

en

t N

itro

ge

n (

%)

0.0

0.5

1.0

1.5

0

2

4

6

Total Sediment N

15N-TN

0.0

0.5

1.0

1.5

0

2

4

6

BB-3

BB-4

Changes in N with Time

• Increase N concentrations starting around the 1940s

• The 15N-TN increases from 0-1 per mill to ~ 4 per mill at the surface

• Suggest more sewage-derived N was/is being introduced to the bay (..has it changed?)

TN

15N-TN

0.0

0.1

0.2

-30

-25

-20

-15

-10

To

tal

Se

dim

en

t P

(%

dw

)

0.0

0.1

0.2

13

C-S

ed

ime

nt

OC

(‰

)

-30

-25

-20

-15

-10

Year

1800 1850 1900 1950 20000.0

0.1

0.2

0.3

0.4

-30

-25

-20

-15

-10

TSP

13C-OC

0.0

0.1

0.2

-30

-25

-20

-15

-10

Changes in P with Time

• Slight increase in P concentrations with time

• The 13C-OC does not change substantially with time (past 50 yrs) except at BB-3

• Lack of relationship between P and 13C-OC suggest that P is not controlling system wide productivity as shown in other aquatic environments

• Large shift at BB-3 reflects changes in vegetation type over time

BB-1

BB-2

BB-3

BB-4

TSP

13C-OC

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Changes at BB -3

1800 1850 1900 1950 2000Sed

imen

t 1

3C

(‰

)

-30

-25

-20

-15

-10

1930s2000s

Year

Potential Changes in:• Vegetation type (C3 versus C4)• C speciation (either source changes or related to temperature increase)

Freshwater diatoms

Marine diatoms

Nitrogen Accumulation Rates (mg N/cm2-yr)

0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.00.0 0.2 0.4 0.6 0.8 1.0

Tim

e (y

ears

)

1900

1920

1940

1960

1980

2000

BB-1 BB-2 BB-3 BB-4

Phosphorus Accumulation Rates (mg P/cm2-yr)

0.00 0.02 0.04 0.06 0.08 0.00 0.02 0.04 0.06 0.08 0.00 0.05 0.10 0.150.00 0.02 0.04 0.06 0.08

Tim

e (y

ear

s)

1900

1920

1940

1960

1980

2000

BB-1 BB-2 BB-3 BB-4

Accumulation of N&P over Time

• Using [N or P], sediment mass, and accretion rates to calculate accumulation rates over time

• Rates change with time, with a general increase in most cores starting in the ~1950s/1960s

• No distinct north-south gradient in rates (highest rate for P at BB-4)

• Can use rates at the surface and over time to estimate sequestration of N and P from wetland sediments

How much N and P are Buried in the Marshes of Barnegat Bay?

Burial rate = 5.2 ± 0.7 g N m‐2 yr‐1 (n = 4)

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OO

SEDIMENT

WATER

Organic N ONH4+

Net Ammonification

N2 (g) flux

ON2 (g)

Denitrification

NO3‐ flux

ONO3‐

Net Nitrification

NH4+ flux

Wetland Nitrogen Cycle

Plant uptakeAlgae and Spartina

NO3‐+ NH4

++ DON

Tidal Exchange

Burial

Watershed N&P Loadings

Barnegat Bay wetlands can sequester a substantial amount of N and P

Comparison of Barnegat Bay marsh nitrogen and phosphorus burial rates measured in this study to rates of nitrogen and phosphorus inputs to the Barnegat Bay.

Nitrogen (kg/yr X105) Phosphorus (kg/yr X105) Inputs 6.9 1.0 Marsh Burial:

Core Top Concentration 6.45 0.88 Avg Concentration (50yrs) 5.48 0.54

Burial as % of Inputs

Core Top Concentration 94% 88% Avg. Concentration (50yrs) 79±11% 54±34%

Nitrogen inputs ranged from 6.5 to 7.65 X105 kg/yr (Hunchak, 2001; Wieben and Baker, 2009; Kennish et al., 2007) while phosphorus input is derived from the Barnegat Bay Characterization Report. Wetland area (26,000 acres, 1.1 X108 m2) are obtained from www.crssa.rutgers.edu/ projects/lc/.

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Diatoms as Indicators of Ecological Change

Indicators of Many Different Variables

• Nutrient Levels• Salinity-Conductivity• pH• Benthic/Planktonic• Water Level • Water Clarity

Smol, J.P. 2008. Pollution of Lakes and Rivers

Sample and Data Needs:

• Well preserved samples • Calibration set (diatom species versus stressor)• Adequate separation of the different groups• Robust change in environmental parameter

Abundance of taxa

Low Nutrient   >>>>>>>>>>>    High Nutrient 

sp. 1

sp. 2

sp. 3

sp. 4

sp. 5sp. 6

Diatoms as Indicators of Ecological Change

Various species of diatoms have variable tolerances for environmental parameters

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Core BB1: diatom‐based inference shows strong N enrichment  starting from 1940s

Cranberry Inlet

Manasquan Inlet

Core BB4: some N increase starting from 1800s

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Barnegat Bay Marshes: Denitrification

Seasonal denitrification rates

3 salt marshes in north, mid‐, and south bay

6 cores per marsh

3 times per year (May, July, October)

Analyze cores for N‐ fluxes, oxygen demand, sediment carbon and nitrogen 

Determine average bay‐wide flux rates (g N m‐2 d‐1)

OO

SEDIMENT

WATER

Organic N ONH4+

Net Ammonification

N2 (g) flux

ON2 (g)

Denitrification

NO3‐ flux

ONO3‐

Net Nitrification

NH4+ flux

Wetland Nitrogen Cycle

Plant uptakeAlgae and Spartina

NO3‐+ NH4

++ DON

Tidal Exchange

Burial

Watershed N&P Loadings

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Factors that can Limit Denitrification in Sediments

• Dissolved oxygen

• Hydrogen sulfide

• Lower pH

• Amt of labile carbon(i.e., easily degradable OC)

• Available nitrate (coupling of nitrification‐denitrification)

• Question:  Importance of Anammox1 and DNRA pathways?

1 ammonium was being converted to N2 (gas)

Denitrification Rates in Three Salt Marshes in Barnegat Bay

IBSP

Reedy 

Horse

MONTH N2 Production (μmol/m2/hr)May 83 ± 14ab

July 121 ± 20a

October 49 ± 19b

Site

Reedy IBSP Horse

N2 p

rod

uct

ion

rat

e (u

mo

l/m

2 /hr)

0

20

40

60

80

100

120

140

160

180

200MayJulyOctober

Other salt marshes12 – 290 μmol/m2/hr(Valiela et al. 2000)

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What are Open Marsh Water Management (OMWM) Systems? 

Mosquito control: since the 1970’s the Ocean County Mosquito Extermination Commission has created over 9,000 ponds across 12,000 acres of salt marsh in Barnegat Bay, NJ.

• Limited amount of information about how it affects marsh accretion and ecosystem services

• How much is enough?: balance between human health and ecosystem health

Strafford 2002 Strafford 2013

Barnegat Bay’sWest Creek in 

2002

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Barnegat Bay’sWest Creek in 

2013

Variation in Vegetated Sediments: Limited Ability to Detect Differences

July 17, 2012

Treatment

Veg Control Veg OMWM Pond OMWM

N2

pro

du

ctio

n r

ate

(um

ol/m

2/h

r)

0

50

100

150

200

250

Horse Creek (southern bay)

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Site characteristics

N2

pro

du

ctio

n (

um

ol m

-2 h

r-1)

0

50

100

150

200

250

MayJulOct

Ponds

OMW

M

Ditches

Non-OM

WM

Ditches Cre

ek

Comparison of N2 Production Among Study Sites 

Edwin B. Forsythe National Wildlife Refuge: 2014

Summary of Denitrification Study

• Denitrification variable in vegetated marsh

• Much less variable in open water interior marsh sites 

• No substantial difference between marsh open water and vegetated sites

• No relationship between porewater sulfide and N2 production

Open water (OMWM) vs Vegetated marsh

Open Marsh Water Management (OMWM)

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OO

SEDIMENT

WATER

Organic N ONH4+

Net Ammonification

N2 (g) flux

ON2 (g)

Denitrification

NO3‐ flux

ONO3‐

Net Nitrification

NH4+ flux

Wetland Nitrogen Cycle

Plant uptakeAlgae and Spartina

NO3‐+ NH4

++ DON

Tidal Exchange

Burial

Watershed N&P Loadings

Nitrogen inputs ranged from 4.6 to 8.6 X105 kg/yr (1989‐2011; Baker et al., 2014) Wetland area (26,900 acres, 1.1 X108 m2) are obtained from www.crssa.rutgers.edu/ projects/lc/ and V. Depaul (USGS)

Comparison of Barnegat Bay Marsh Nitrogen Removal Rates Measured to Rates of Nitrogen Inputs to Barnegat Bay

Nitrogen (kg/yr X105)Inputs (1989-2011; Median) 6.73

Marsh Burial:Core Top Concentrations 6.1 ± 0.02

Avg Concentrations (50yrs) 5.2 ± 0.71

Burial as % of InputsCore Top Concentrations 91%

Avg. Concentrations (50yrs) 77%

Marsh Denitrification:May 0.47July 0.70Oct 0.30

Avg ± SD 0.49 ± 0.20

Denitrification as % of Inputs 7.30%

Total Removal 84-98%

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Summary and Conclusions

• Remaining wetlands play important role in nutrient cycles in Bay

• Plant uptake‐sediment burial can sequester carbon, nitrogen and phosphorus (nutrient trading?)

• Denitrification is an important process for nitrogen removal in wetlands

• OMWM sites have similar rates in whole marsh

• Studies showcase the importance of BB wetlands and maintaining and increasing area

AcknowledgementsPatrick Center for Environmental ResearchRoger ThomasPaul KiryMike ArcherMelissa BrossStephen Dench Megan NyquistKirk RaperLinda ZaoudehPaula Zelanko

We thank the support of Thomas Belton and NJ DEP.

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Barnegat Bay’sWest Creek in 

2013