Nitrogen Driven Degradation of Long Island Water Bodies

Christopher J. Gobler, Ph.D.Stony Brook University, School of Marine and Atmospheric Sciences

“Nitrogen is the critical limiting factor to algal growth in Long Island coastal marine waters” – Dr. John Ryther, Woods Hole Oceanographic Institute,Science Magazine, 1971

Population, Suffolk County, NY, USA

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

Popu

latio

n

New York City

Long Island

>25,000,000 lbs of nitrogen per year from human waste

Septic tank

Water table / aquifer

Nitrogen

In Suffolk County, 70% of homes have septic tanks or

cesspools.

In eastern Suffolk County, more than 90% of homes

have septic tanks or cesspools.

Long Island Legacy:Household wastewater

Nitrogen

Groundwater flow

1987 20050

1

2

3

4 Glacial Magothy

Nitr

ogen

con

tent

(mg/

L)

18 year change in groundwater nitrogen levels

40% increase

200% increase

Suffolk County Comprehensive Water Resources management plan, 2010

Rising nitrogen levels in our bays

12/2/73 8/11/87 4/19/010.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

f(x) = 1.71180233868894E-05 x − 0.0300213789274482R² = 0.041180092418925

Tota

l Kje

ldah

l nitr

ogen

(mg/

L)

4/16/75 10/6/80 3/29/86 9/19/91 3/11/970.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

f(x) = 2.64343103508642E-05 x − 0.657237814861096

Great South Bay Peconic Estuary

Samples for eelgrass genetic analyses

Hempstead Bay, Great South Bay, Moriches Bay, Quantuck Bay, and Shinnecock Bay listed on the NYSDEC 303d list of impaired water bodies due to “onsite waste disposal and

urban runoff”.

NYSDEC Impaired Water Bodies list

100 kilometers!¼ of L.I. coast!

Wastewater =55%

Atmospheric deposition = 30%

Fertilizer= 15%

Nitrogen budget for Great South Bay

Kinney and Valiela, 2011

•~70% of N entering Moriches and Shinnecock Bay is from wastewater (Gobler et al, in progress for NYSDOS).

Peconic nitrogen loading budgets

What impairments are brought about by excessive nitrogen loading?

• Loss of critical habitats: Eelgrass, salt marshes• Low dissolved oxygen levels, hypoxia• Acidification, low pH• Macroalgal blooms: Sea lettuce, Ulva• Toxic algal blooms: Red tides, brown tides• Loss or depletion of shellfisheries and finfisheries

Nitrogen impacts on salt marshes• Salt marshes are critical habitats for protecting land, filtering

terrestrial pollutants, migratory birds, and marine life on Long Island.

• Nitrogen is accelerating the disappearance of salt marshes across Long Island.

Salt marshes protect bayside properties from wave energy

CAT scans of marsh roots

Nitrogen loading as a driver of salt marsh loss on Long Island, Deegan et al 2012, Nature

Collapsing salt marsh

Western Bays, Nassau County

Eelgrass: Critical benthic habitat

Eelgrass: Critical benthic habitat

Nitrogen impacts on seagrasses• Eelgrass are critical habitats

for marine life on Long Island.

• Nitrogen is accelerating the disappearance of eelgrass across Long Island.

Impacts of nitrogen loading on seagrass

Effect of nitrogen load on eelgrass growth, Peconic Estuary

0 230 480 7000

20

40

60

80

100

120

Nitrogen loading (µM)

Leaf

mas

s (m

g / S

S)

Rodgers 2010; Rodgers, Peterson, Gobler, in prep

Regional view of nitrogen pollution index of salt marshesDr. Fred Short, UNH

Long Island eelgrass beds show multiple signs of

degradation due to enrichment with sewage-

derived nitrogen.

Low (no) oxygen -another consequence of excessive nitrogen loading (Hewlett Bay)

1-Mar1-Apr

1-May1-Jun

1-Jul1-Aug

1-Sep1-Oct

1-Nov1-Dec

0

2

4

6

8

10

12Bottom NYS acute standard

Diss

olve

d O

xyge

n, m

g L⁻

¹

Samples for eelgrass genetic analysesHarmful algal blooms across Long Island

PSP, DSP PSP, DSP

Brown tide

Cochlodinium

Cochlodinium

CochlodiniumPSP

Brown tideCochlodinium PSP DSP

PSP

PSP

Toxic cyanobacteria

Toxic cyanos Toxic cyanos

Ulva

Ulva

Ulva

DSP

Alexandrium red tides and paralytic shellfish poisoning (PSP)

AlexandriumSaxitoxin

Saxitoxin producing Alexandrium fundyense in NY waters

= cells not detected

= < 100 cells L-1

= > 1,000 cells L-1 = 100 - 1,000 cells L-1

PSP-shellfish bed closures across Long Island since

2006

Northport-Huntington Bay

Expansion of PSP-induced shellfish bed closures on Long Island, 2005 – 2012

Prior to 2006, Long Island had never experienced a PSP event

2005 2006 2007 2008 2009 2010 2011 20120

2000

4000

6000

8000

10000

12000

14000

Acre

s of s

hellfi

sh b

eds c

lose

d by

PS

P

Northport BayNorthport and Huntington Bay

Northport, Huntington, and Shinnecock Bay

Northport, Huntington, and Shinnecock Bay, Mattituck Inlet and Sag Harbor Cove

Wastewater

N

Wastewater-derived nitrogen is promoting the intensity and toxicity

of Alexandrium blooms.

Samples for eelgrass genetic analyses

Brown tideCochlodinium Alexandrium Dinophysis

Enhanced nutrient loading more intense &/or toxic HABs

Gobler et al 2012

Gobler et al 2011, Gobler and Sunda 2012

Hattenrath et al 2010

Hattenrath et al in prep

Ulva

Wallace and Gobler,

submitted

Nitrogen impacts on shellfish• Landings of clams and scallops have declined 99% since 1980.

• Linkages to nitrogen driven HABs, habitat loss, and water quality degradation.

1970

1972

1974

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2006

0

100,000

200,000

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500,000

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700,000

800,000

Hard clam landings (bushels) in Great South Bay

What impairments are brought about by excessive nitrogen loading?

• Loss of critical habitats: Eelgrass, salt marshes• Low dissolved oxygen levels, hypoxia• Acidification, low pH.• Macroalgal blooms: Sea lettuce, Ulva• Toxic algal blooms: Red tides, brown tides• Loss or depletion of shellfisheries and finfisheries