Dr. Dorothy Peteet
Originally presented 14 Feb 2004
Introductory Presentation by Dr. Michael J. Passow
Today’s E2C program welcomes Dr. Dorothy Peteet, who studies the Hudson River from a different viewpoint than our previous guest researchers on this theme. Dr. Peteet examines the fossils preserved in the marsh sediments along the river to understand the climatic and other changes that the Hudson system has undergone during the past 10,000 years or so since the end of the Ice Age.
For examples of pertinent New York State “Physical Setting: Earth Science” Core Concepts, click here.
Science Content
Salt, brackish, and freshwater marshes of the Hudson River provide crucial habitat as nurseries with food and protection for Hudson River fishes. The variety of marsh habitat with specific plant communities results in specific invertebrate and higher vertebrate habitat. How have these marshes changed over time? What influences have humans had on these marshes? Sediment, pollen, and macrofossil stratigraphy from sediment cores is coupled with high-resolution AMS C-14 dating to document the history of climate and land-use change in the Hudson Estuary since deglaciation.
Sites ranging from Jamaica Bay and Staten Island northward to Piermont Marsh and Iona Island record changes in foraminifera, charcoal, and local vegetation that accompany shifts in salinity. Regional vegetational shifts implied from pollen stratigraphy document the decline in tree abundance with the arrival of Europeans, and the subsequent reforestation since 1900. Jamaica Bay salt marshes are about 600-800 years old, with the latest 400 years in 1 meter of Spartina and Distichlis marsh growth. Elphidium foraminifera and Fundulus (killifish) in shallow, sandy higher salinity conditions were replaced by marsh species such as
Trochammina and Miliammina which are present today. The marshes were formed probably due to protection of these environments by the southeastward growth of Rockaway Spit.
A Staten Island salt marsh evolved as sea level rose over existing shallow freshwater ponds in a deglacial environment. The most recent millennium shown by pollen stratigraphy documents the striking rise in weedy species due to the European impact of logging, agriculture, and industry which began in the 1600’s. Prior to the 1600’s, changes in forest community and climate are suggested by higher percentages of pine, hemlock and hickory, and these changes are reflected as well in the pollen stratigraphy of Jamaica Bay.
Piermont Marsh, located approximately 40 kilometers north of the mouth of the Hudson River shows a consistent presence of “weedy” genera (Ambrosia, Plantago, and Rumex) beginning around 1760. This increase in herbaceous genera is also marked by a decline in arboreal taxa, attributed to land clearance by settlers. Typha (cattail) also experiences a very large increase coincident with the rise in weedy genera, accounting for as much as 70% of pollen grains counted in a sample. Although the profile for Gramineae (grass) appears consistent throughout the core, size separations show periods dominated by the native marsh Spartina species downcore and the invasive Phragmites in recent decades. A pre-settlement interval shows a period of decreased pollen deposition and increased charcoal, which could be due to sea level change, drought, or Native American use. Comparison of sedimentation rates in the Hudson River estuary marshes show major increases in organic matter accumulation since the European impact.
Technology Tips for the Classroom
by Dr. Cristiana Assumpção
For information on educational technologies and ideas on how to use the Earth2Class materials in your classrooom, see the tutorials in the MENTORING section of our website http://www.earth2class.org/mentoring/technology.htm
The study of water has attracted a lot of good ideas as to how students can work together to become aware of the major issues we are currently facing in relation to this dwindling resource, and learn what they can do to help preserve such an important natural resource.
Resources
Lamont-Doherty Hudson River Studies
LDEO’s Riverscope Pilot Project http://xtide.ldeo.columbia.edu/hudson/
LDEO’s Commitment to the Hudson River http://www.ldeo.columbia.edu/Hudson/about/index.html
http://www.hudson.columbia.edu/
“Hudson River Estuary Enters Middle Age” http://www.ldeo.columbia.edu/news/2004/02_05_04.htm
Selected Educational Web Sites:
EPA Classroom & Activities about Drinking Water http://www.epa.gov/safewater/kids/exper.html
US Geological Survey Water Resources Education Information http://water.usgs.gov/education.html
AMS Water in the Earth System http://64.55.87.13/amsedu/WES/home.html
Project WET (Water Education for Teachers) http://www.dec.state.ny.us/website/education/whatWET.html
Athena: Earth and Space Activities for K – 12 http://inspire.ospi.wednet.edu:8001/
Virtual Trip Up the Hudson by William Wade, Master Engraver, 1846http://hhr.highlands.com/virtual.htm
Selected Links used in this session’s PowerPoint:
EPA “Surf Your Watershed” http://cfpub2.epa.gov/surf/locate/index.cfm
Hudson River Maritime Museum http://www.ulster.net/~hrmm/welcome.html
Hudson River Sloop “Clearwater” http://www.clearwater.org
Hudson River Watertrail Association http://www.hrwa.org/index.html
Information Resource for the Hudson Valley http://hudsonriver.com
NOAA National Oceanic Services (NOS) http://www.nos.noaa.gov
Tides: http://www.nos.noaa.gov/topics/navops/ports/welcome.html
New York Geology Resource Page http://www.albany.net/~go/newyorker/
NYS Dept. of Environmental Conservation, Div. of Fish, Wildlife, and Marine Resources http://www.dec.state.ny.us/website/dfwmr/
NYS DEC Hudson River home page http://www.dec.state.ny.us/website/hudson/
NYSDEC Hudson River Management Action Plan http://unix2.nysed.gov/edocs/encon/hud_plan.htm
Tappan Zee Bridge http://www.nycroads.com/crossings/tappan-zee/
USGS Hudson River National Water Quality Assessment home page http://ny.water.usgs.gov/htmls/pub/nawqaweb/
USGS Hudson River Salt Front http://ny.usgs.gov/htdocs/dialer_plots/saltfront.html