Lecture 8: Anthropomorphic Change

1
Lecture 8 Anthropomorphic Change

• Farming, Oysters, Sucession

2
Objectives

• Understand how the colonists altered the land
  surrounding the Chesapeake Bay
• Understand how the colonists altered the
  near-shore communities of the Chesapeake Bay
• Be able to describe the process of succession
  with respect to the Chesapeake Bay

3
Farming

• Indians method of farming maintained the
  topography of the land
• No metal implements e.g. axes or plows
• treated land as gift from Manitou
• Colonists method of farming altered the
  topography of the land
• Metal implements used to fall trees and till soil
• Land belonged to colonial user

4
Tobacco

• Chief cash crop of colonists (big buck export
  item used to make cigars)
• first cultivated in Chesapeake Bay Region by John
  Rolfe (came from West Indies)
• Demands rich soil
• Depletes soil of nutrients in 5 yrs. so there
  was a great need to clear more land
• labor intensive crop demanding additional workers

5
Tobacco Pictures

• Tobacco requires
• early germination under burlap
• planting
• topping
• harvesting
• drying
• rotation

6
Oysters

• Full lecture following Spring Break
• Sessile (cannot move so cannot run away)
• Tasty?
• Can be eaten year round although best during
  months of the year containing R
• Readily available during colonial time

7
Oyster Pictures
8
The Oyster Story
9
The Oyster Story

• Oysters record changes in Bay conditions
• Meats accumulate heavy metals environmental
  toxins as a result of the oysters feeding via the
  filter method.
• Shell is a permanent record of Bay conditions
  and position in the water column. The shell
  (mantle) grows daily trapping water within the
  shell. Growth is modified by temperature and
  pressure

10
Oyster Story

• 3 shell morphologies
• Sand oyster
• ridges on shell
• height roughly width
• Mid-water oysters
• no pronounced ridges
• length exceeds width
• Tongue Oysters
• length gtgt width

11
Colonial Garbage

• Colonists did not have indoor plumbing so they
  utilized Privies (out houses).
• Several times a year the waste material would
  be layered with dirt and shell to reduce odor
• Trash was also disposed in a pit (typically an
  old well) and routinely layered with shell

12
Oyster Analysis

• There is a gradual change in the kind of oyster
  shell morphology correlated with the length of
  time a colony existed at a particular site
• The early privy layers have predominately sand
  oyster shell morphology but the newer layers have
  mid-water shell morphology

13
Summary

• Tobacco farming initiated change in near shore
  terrestrial communities
• Loss of tree cover
• Loss of food for animals
• Soil nutrient depletion
• Erosion
• Changes in near shore aquatic communities can
  also be documented
• over use of resources

14
Succession

• Defined as a gradual change in an ecosystem
  whereby species are introduced/replaced over
  time usually culminating in a stable climax
  community.
• The terrestrial/ aquatic interface is a dynamic
  region subject to rapid physical, chemical, and
  biological change.

15
Recollect

• The Bay is shallow with most shoulders being
  less than 15 feet deep
• Most near shore terrestrial communities are farm
  or lawn, some forest.
• Both areas subject to extreme weather conditions

16
MarshlandFresh, Estuarine, Marine
17
Marshland Importance

• Part of both aquatic and terrestrial food chain
  plants directly consumed by herbivores
• Harbor sources of nitrogen fixation
• Decay of marsh plants releases vitamins and
  minerals
• Detritus (organic matter) washes out of marshes
  for use by deep water communities
• Stabilize sediments
• Oxygenate waters
• Source of substrate for attaching organisms

18
Marsh Location

• This false color infrared - visible image is
  composed of three separate Thematic Mapper images
  acquired in the summer of 1993. TM bands 4,3 and
  5 were used here. In general, red areas show
  healthy vegetation, green areas are urban.
  Light-blue to white areas are generally
  indicative of bright soil - they possibly
  represent agricultural areas. Marshes appear as a
  deeper blue. Large marsh islands, such as
  Bloodsworth, are visible near the center of the
  picture. Black areas represent open water.

19
References

• http//www.gmu.edu/bios/bay/cbpo/intro.htmwetland
  s
• http//www.inform.umd.edu/wetlands/index.html
• Metzgar, R. 1973. Wetlands in Maryland.
  Publication 157. Dept. of State Planning, State
  of Maryland.