ABSTRACT

1
Paleoecology, Organic Matter and Carbon Content
of Decodon Pond (fresh) and Jamaica Bay (tidal)
NY Wetlands
METHODS
ABSTRACT

• 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 25-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 100C, 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.

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.
Depth (cm)
DISCUSSION AND CONCLUSIONS
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

• 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.

Fig. 3
Fig.4

Density (g/cc)
Fig 1 Decodon Pond core
INTRODUCTION
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?
Jamaica Bays Big Egg Marsh
Fig. 6
Fig. 5
PLANT LIFE IDENTIFIED FROM MACROFOSSILS
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
Peteet Sanpisa Stritrairat Mr. Argie Miller David
Cruz
Decodon Pond
SPRUCE
BRASENIA
CAREX
NAJAS