ABSTRACT

INTRODUCTION

METHODS

DISCUSSION AND CONCLUSIONS

• Sediment cores were taken from Decodon Pond wetland using a Livingston corer, and from Jamaica Bay Big Egg Marsh using a Dachnowsky corer. Total depth of samples are 166 cm and 169 cm respectively.

•Cores were subsampled as follows: Decodon core 1: 10-cm intervals, Decodon core 2:5-cm intervals, and Big Egg: 10-cm intervals.

• 20 cc or more of sediments were screened through a 500 micron strainer. Macrofossils (such as seeds, leaves, charcoal, and pebbles) were picked and identified under a dissecting microscope at 10x magnification with the help of Sanpisa Sritrairat and Dr. Peteet.

• Samples were analyzed for lost-on-ignition (LOI) by drying samples for 24-hr at 100°C, then burning them at 375 °C for at least 1 hr. Weights were recorded at each step. LOI = amount of organic matter = Dry weight – burnt weight. Inorganic content = weight after 375 °C burning.

•Amount of carbon sequestrated and stored in the sample = 1/2 x LOI x m/v

•Macrofossil chart was plotted using Tilia program, while other calculations were done using Microsoft Excel.

•I. Decodon Pond, Queens

•An aquatic assemblage of plant life (Fig.2), including Potamogeton, Brasenia, Najas, was found at many depths over time in the pond, especially near the bottom, indicating presence of open water.

•Carex, Cyperus, and Sparganium which grow under wetland conditions, were found at 0-80 cm (upper portion), suggesting that the pond dried out or become much shallower (Fig.2)

•Decodon Pond LOI rapidly increases above 80 cm (Fig.2). This coincides with an increase in emerged wetland species which may have higher productivity.

•A spruce needle was found at the depth of 200cm (Fig.2). The natural range of spruce is north of Queens today, suggesting that the climate would have had to have been cooler for the area to support spruce.

• Fig.3 and Fig. 4 show an increase in organic content per volume, and a drop off of inorganic matter which might be due to the change in land use and ecosystem type.

•Up to 200 particles of charcoal /sample were found at depths of 0-40cm (Fig 2). This may corresponds to the past 400 hundred years and the timing of the European Settlement.

Thus, human may have changed the natural fire cycle.

•Big Egg Marsh, Jamaica Bay, Queens

•Fig. 5,6 suggests that LOI at Big Egg marsh also increases over time. Inorganic matter decline might be due to human activity such as damming of streams which may reduce inorganic input.

•%LOI and % carbon is about 2 times higher in the Decodon Pond core (fresh) than in the Big Egg core (salty), which is probably a result of different productivity and preservation conditions in the two types of wetlands.

•Inorganic content is higher overall in the Jamaica Bay core than in the Decodon Pond core, reflecting the sand from the marine setting.

•Further macrofossils analysis on Jamaica Bay core will help to understand the ecosystem changes at this site.

NAJASCAREX

BRASENIA

PLANT LIFE IDENTIFIED FROM MACROFOSSILS

SPRUCE

Decodon Pond Core 2 Organic/Inorganic Density

0.00 0.10 0.20 0.30 0.40 0.50

10

48

87

103

116

129D

epth

(cm

)

Density (g/cc)

Organic matter Inrganic matter

Decodon Pond Core 1 Organic/Inorganic Density

0.00 0.05 0.10 0.15 0.20 0.25 0.30

9

44

79

109

147

Dep

th (

cm)

Density (g/cc)

Organic matter Inrganic matter

Decodon Pond Core 1 Organic/Inorganic Density

0.00 0.05 0.10 0.15 0.20 0.25 0.30

9

44

79

109

147

Dep

th (

cm)

Density (g/cc)

Organic matter Inrganic matter

Decodon Pond

Jamaica Bay’s Big Egg Marsh:

Sponsors:National Aeronautics and Space Administration

(NASA)NASA Goddard Space Flight Center (GSFC)

NASA Goddard Institute for Space Studies (GISS)NASA New York City Research Initiative (NYCRI)

Contributors:Dr. Dorothy PeteetSanpisa Stritrairat

Mr. Argie MillerDavid Cruz

LOI Comparison of 2 Big Egg Cores

0

20

40

60

80

100

120

140

160

180

0.0 10.0 20.0 30.0 40.0 50.0

LOI (%)

De

pth

(c

m)

08BigEgg2 03BigEgg

101520253035404550556065707580859095

100105110115120125130135140145150155160165170

De

pth

Spruc

e ne

edle

Cyper

us s

trigo

sus

Carex

Sparg

aniu

m

Brase

nia

Potam

oget

on

Najas

Daphn

ia

20 40 60 80

LOI

50 100 150 200

Charc

oal

50 100 150

Sand

Dep

th (

cm)

This study is a stratigraphic examination of core sediment samples collected from Decodon Pond in Alley Pond Park at Queens, New York on January 30, 2008 and core sample sediments collected on July 21, 2008 in Jamaica Bay, Queens, NY. We examine macrofossils in Decodon Pond core and organic matter content in both cores. Decodon Pond macrofossils record indicates significant vegetation shifts, organic matter and charcoal increases, and change in lithology toward the present time. Jamaica Bay core exhibits changes in LOI and inorganic matter density as well.

Paleoecology and paleoclimatology are sciences in which analyses of pollen, spores, macrofossils, and any other proxies in sediment sample are used to reconstruct ecosystems and climate of the past. Decodon Pond was chosen because it is one of a series of unusual, intact 15,000 year old kettle ponds within the New York City limits. Jamaica Bay was chosen due to its location as well as high biodiversity in the marsh. Since both are within the vicinity of New York City, human impacts maybe easily identified by looking at the changes in vegetation and lithology.  The paleoecological study in this area may give an insight toward wetlands restoration and protection from human and climate change in the future. Wetlands are ideal places to collect sediment samples as the sites are anoxic. Therefore, pollen, spores, and macrofossils are well preserved due to low microbial degradation and oxidation. We conducted this study to answer: How do organic matter content and vegetation in salt marsh and nontidal wetlands compare?

Fig 1: Decodon Pond core

Fig. 5:

Fig. 3: Fig.4:

Fig.2 Macrofossils and LOI in Decodon Pond Core. The unit of macrofossils count is number of occurrence per 20 cc sample, and LOI is in %

Density (g/cc)

08Big Egg 2: Jamaica Bay Organic/Inorganic Density

0.00 0.20 0.40 0.60 0.80 1.00 1.20

0.5

19.5

39.5

59.5

79.5

99.5

119.5

139.5

159.5

De

pth

(c

m)

Density (g/cc)

Organic matter Inrganic matter

Fig. 6:

Paleoecology, Organic Matter and Carbon Content of Decodon Pond Paleoecology, Organic Matter and Carbon Content of Decodon Pond (fresh) and Jamaica Bay (tidal) NY Wetlands(fresh) and Jamaica Bay (tidal) NY Wetlands