STUDENT WORKSHEET
FORAYS WITH FORAMS
Name______________________________
Date___________________
ACTIVITY: NEW ZEALAND CORE
The three laminated sheets represent microscope views of foram samples from layers an ocean core from east of New
Zealand: Sample 1 (10,000 ybp), Sample 2 (15,000 ybp), and Sample 3 (20,000 ybp).
(YBP = years before present)
1. Using the laminated identification key for Indicator Species and the Data Sheet on Page 2,
identify and record the number of each indicator species present in each of the samples.
To simplify this exercise in the interest of time, each sample contains 25 forams (with species proportional
to the percentages in the actual core). You can check your data by adding the numbers of indicator
species recorded for each sample, making sure the total equals 25.
2. For each species identified in a sample, calculate and record that species’ percentage of the total forams
in the sample. Because each sample contains 25 forams, 100% of the sample is 25 * 4, so you can use
the same proportion to determine each individual species’ percentage. You can check your calculations by
adding all percentages in a sample, making sure the total equals 100%.
3. For each sample in the diagram below, plot and color in the percentage of each indicator species in the
pie chart, using the colors corresponding to those in the identification key. The blank pie charts are
divided into 20 segments, each representing 5%. Starting at the top of the pie (“12 o’clock” position) and
proceeding clockwise, plot the species in the order they are listed in the Data Sheet columns.
4. Use the pie chart colors and the Identification Key to determine the Foraminiferal Province for each of
the three samples.
SAMPLE 1 – 10,000 ybp
Foraminiferal Province:
___________________________
SAMPLE 2 – 15,000 ybp
Foraminiferal Province:
___________________________
SAMPLE 3 – 20,000 ybp
Foraminiferal Province:
___________________________
5. Based on your results, what happened to ocean temperatures during the period from 20,000 ybp to
10,000 ybp?
6. Can you think of a major climate event that was the likely cause of this trend?
Forays with Forams
MathScience Innovation Center 2014
PAGE 2
DATA SHEET
FORAMINIFERA INDICATOR SPECIES IN CORE SAMPLES
SAMPLE 1
10,000 ybp
FORAM
SPECIES
Globorotalia
menardii
# in
Sample
% of
Sample
SAMPLE 2
15,000 ybp
# in
Sample
% of
Sample
SAMPLE 3
20,000 ybp
# in
Sample
% of
Sample
Pulleniatina
obliquiloculata
Neogloboquadrina
dutertrei
Globigerinella
siphonifera
Globigerinoides
ruber
Globigerinoides
sacculifer
Globorotalia
inflata
Neogloboquadrina
pachyderma
(>50% rt. coiling)
Globigerina
bulloides
Globigerina
quinqueloba
Neogloboquadrina
pachyderma
(>50% left coiling)
Neogloboquadrina
pachyderma
(≈ all are left
coiling Neos)
**
TOTALS
**
DO NOT enter data in this row unless the sample is
composed almost entirely of left coiling Neogloboquadrina
pachyderma.
Forays with Forams
MathScience Innovation Center 2014
ACTIVITY: CHESAPEAKE BAY BENTHIC FORAMINIFERA
PAGE 3
The three laminated sheets for this activity represent microscope views of benthic foram samples from a core in the
tidal Patuxent River where it joins the Chesapeake Bay. (The field of view represented is the same as for the New
Zealand core, approx.. 6 mm diameter.) Samples have been dated for the following calendar years: 1750, 1800, 1850,
1900, 1965, 1975, and 1990
1. Using the laminated identification key for Major Benthic Foraminifera of the Chesapeake Bay and the
Data Table on Page 4, identify and record the number of each indicator species present in each of the 3
samples.
2. To simplify this exercise in the interest of time, each sample contains 20 forams (with species proportional
to the percentages in the actual core). You can check your data by adding the numbers of indicator
species recorded for each sample, making sure the total equals 20.
3. For each species identified in a sample, calculate and record that species’ percentage of the total forams
in the sample. Because each sample contains 20 forams, 100% of the sample is 20 * 5, so you can use
the same proportion to determine each individual species’ percentage. You can check your calculations by
adding all percentages in a sample, making sure the total equals 100%.
Using your results in the data table and the descriptions of the benthic foram species in the key, answer the following
questions:
4. In what year do you see the first appearance of forams tolerant of low oxygen conditions?
5. In what year do the forams in Question 4 begin to constitute the largest percentage of the benthic species?
6. What is unusual about the forams in the sample from 1990?
7. What do your answers to Questions 4 -6 suggest about dissolved oxygen trends in the Chesapeake Bay and
its tidal tributaries?
8. In what year was the salinity of the water unusually high?
9. What does this suggest about possible climate conditions during that time?
Virginia’s Jamestown colony was founded in 1607 but nearly failed in 1609 and 1610 when the colony suffered an
appallingly high death rate. One of the major factors affecting the region during those years was a period of severe
drought during 1606-1612, documented in studies of tree rings. (The width of the tree ring indicates how much the
tree has grown in a particular growth season: the wider the ring, the better the conditions for growth. As shown in
the picture below, tree rings from 1606-1612 were narrower than average.) Droughts would have affected the
colony's supply of food and clean water.
10. What would you expect to see in a core sample of benthic forams in the
Bay or the tidal James from this time period?
Jamestown Drought
1606-1612
Forays with Forams
MathScience Innovation Center 2014
PAGE 4
DATA TABLE
BENTHIC FORAMINIFERA IN TIDAL PATUXENT RIVER
Ammonia
parkinsonia
YEAR
# in
Sample
% of
Sample
Elphidium
selseyense
# in
Sample
% of
Sample
Ammobaculites
crassus
# in
Sample
1990
1975
1965
1900
1850
1800
1750
Forays with Forams
MathScience Innovation Center 2014
% of
Sample