long-term vegetational change in a new york city freshwater wetland argie miller, dorothy peteet,...

LONG-TERM VEGETATIONAL CHANGE

IN A NEW YORK CITY

FRESHWATER WETLAND

Argie Miller, Dorothy Peteet, David Cruz

• Carbon storage pools in the global carbon cycle

• Preserve water quality and water supply

• Protection against flooding and erosion

• Essential habitat for fish and wildlife

• Archives for paleoecology

Services of Wetlands

• Three Kettle Ponds Lilly, Decodon, and Turtle

Ponds

• 15,000 years old

• Glacial-age remnant

Alley Pond Park (40o45’21.55”N; 73o45’38”W)

Queens, NY

• Ice sheet melted, dropped huge chunks of ice

• Ice became buried in the outwash.

• Depressions filled with water and sediment.

Kettle Pond

•Research Team:I.C.C Model Independence Critical Thinking Communication

•Coring with LivingstonPiston corer

• Stratigraphic examination

•200 cm deep sediment core

Methods

EXAMINED:

•Preserved fossil seed/needle remains

•Charcoal particles • Sand and silt

Paleoecological Changes

0.00 0.10 0.20 0.30

9

44

79

109

147

Density (g/cc)

De

pth

(c

m)

Turtle Pond Core 1 Organic/Inorganic Density

Organic matter Inrganic matter

0.00 0.10 0.20 0.30

9

44

79

109

147

Density (g/cc)

De

pth

(c

m)

Turtle Pond Core 1 Organic/Inorganic Density

Organic matter Inrganic matter

0.00 0.10 0.20 0.30 0.40 0.50

10

48

87

103

116

129

Density (g/cc)

De

pth

(cm

)

Turtle Pond Core 2 Organic/Inorganic Density

Organic matter Inrganic matter

Loss onIgnition

(LOI)

Macrofossils

UPPER SAMPLES(Aquatics and emergent)

Potamogeton Brasenia NajasZannichellia

Macrofossils 1

CAREX SPP

CYPERUS STRIGOSUS

SPARGANIUM

Macrofossils 2

LOWER SAMPLEViolaCarexPica (spruce) NeedleCyperus StrigosusSparganiumDaphnia egg case

Macrofossils 3 Charcoal Fragments

•suggest a large increase in fire near the pond above 20cm •At lower depths, a steady low pattern of accumulation

Sand•Sand abundance was variable •highest at 160-140 cm depth.

Results Increasing organic matter in upper sediments, suggesting wetter environment, possibly wetter climate.

Questions1.Why is deposition rate so low, if kettle? why not 10 meters deep, like nearby Alpine Swamp in New Jersey or Moravian Swamp, Staten I?

2.How old is spruce needle at bottom? Does it represent boreal forest after ice melt, or Little Ice Age more recently? Spruce does not occur naturally in NYC today

• Records of climate change in New York City region are sparse.

• Research needed to document rates of change and human impact

• Compare natural frequencies of fire to human-induced fire activity.

Conclusions

AcknowledgementsDorothy Peteet, PhD Principal InvestigatorDavid Cruz Student