Biology I – Ms. Hughes
 Student information sheet
 My information
 Parent letter – lab safety contract
 Course overview
 Observation – scientific method
 Scientific Method
 Purpose – observation
 Hypothesis – rational reason for observation
 Independent variable , dependent variable, control group
 Methods/procedure – detailed way of testing hypothesis
 Results/analysis – the measurements you receive from your
methods
 Conclusion – what your data/measurements tell you – this is
where you accept or reject your hypothesis
Problem Statement
Gracilaria vermiculophylla, a newly arrived invasive
macro algae has been introduced into Southern Beaufort
County estuaries. As an invasive species, it has the
potential for negative community impacts such as
competitive displacement of other macroalgae, and other
native symbionts and increased mortality of Diopatra
cuprea. As a newly introduced species its presence may
have a significant effect on the carbon budget including
competitive fixation of CO2 as well as O2 consumption
during degradation.
Hypothesis Statements
 The current presence of Gracilaria vermiculophylla has
increased carbon fixation levels per meter squared, which
prior to this study has not been quantified.
 That Gracilaria vermiculophylla is physically displacing most
other symbionts in the intertidal zone, along with negatively
effecting Diopatra cuprea populations.
 That there is a distinct pattern of Gracilaria vermiculophylla
density along the intertidal gradient.
Methods
 Carbon Fixation: Quadrat sampling with recording of
quantity of Gracilaria vermiculophylla plumes per quadrat.
NPP estimated by measuring of ash free dry weight per
quadrat.
 Symbiont Displacement: Quadrat sampling of Diopatra
cuprea tube caps. Recording of type of symbionts
attached per tube cap.
 Distinction of Densitiy patterns: Quadrat sampling and
recording of amount of Gracilaria vermiculophylla plumes
found per quadrat across the intertidal gradient.
Diopatra Cuprea Density
Hilton Head
Plantation
High 1
Low 1
High 1
*
Low 1
0.001400884
High 2
Low 2
0.285843434
*
High 2
Low 2
0.001400884
*
0.285843434
*
*
*
0.000320071
0.000003435
*
0.000320071
0.000003435
*
1 and 2 are indication of separate sampling dates
Comparison of densities by dates (t-test, P= 0.05 n ≈ 15)
There are significantly more Diopatra cuprea found in high density areas than low
density areas. There is a significant temporal change in low density plots however
there is no significant temporal change in high density plots.
Gracilaria vermiculophylla Density
Hilton Head
Island
High 1
Low 1
High 1
*
Low 1
0.000674
High 2
Low 2
0.154991
*
High 2
Low 2
0.000674
*
0.154991
*
*
*
0.009209
0.000003
*
0.009209
0.000003
*
1 and 2 are indication of separate sampling dates
Comparison of densities by dates (t-test, P= 0.05 n ≈ 15)
There is a significant spatial difference between high and low densities plots.
There is a significant temporal difference in low density plot areas but there is
no significant temporal difference between high density plot areas.
Gracilaria vermiculophylla Carbon Fixation
Hilton Head
Island
High 1
Low 1
High 1
*
Low 1
0.00514103
High 2
Low 2
0.04187572
*
High 2
Low 2
0.00514103
*
0.04187572
*
*
*
0.00003037
0.0000271
*
0.00003037
0.0000271
*
1 and 2 are indication of separate sampling dates
Comparison of densities by dates (t-test, P= 0.05 n ≈ 15)
High density plots have significantly more carbon input than low density plots
showing a significant spatial difference. Carbon fixation also increases
temporally in high and low density plots.
Diopatra cuprea Density
Parris Island
High 1
Low 1
High 1
*
Low 1
0.0000527
High 2
Low 2
0.909780
*
High 2
Low 2
0.0000527
*
0.909780
*
*
*
0.000003
0.251224
*
0.000003
0.251224
*
1 and 2 are indication of separate sampling dates
Comparison of densities by dates (t-test, P= 0.05 n ≈ 15)
There is a significant temporal difference between low density plots, there is no significant
temporal difference between high density plots. There was a significant spatial difference
between the high and low density plots in the earlier sampling but there was no significant
spatial difference between the high and low densities plots on the later, second sampling
later in the season.
Gracilaria vermiculophylla Density
Parris Island
High 1
Low 1
High 1
*
Low 1
0.0000500
High 2
Low 2
0.225684661
*
High 2
Low 2
0.0000500
*
0.225684661
*
*
*
0.0000032
0.2575238
*
0.0000032
0.2575238
*
1 and 2 are indication of separate sampling dates
Comparison of densities by dates (t-test, P= 0.05 n ≈ 15)
There is a significant temporal difference between low density plots, there is no
significant temporal difference between high density plots. There was a significant
spatial difference between the high and low density plots in the earlier sampling but
there was no significant spatial difference between the high and low densities plots on
the later, second sampling later in the season.
Gracilaria vermiculophylla Carbon Fixation
Parris Island
High 1
Low 1
High 1
*
Low 1
0.000387557
High 2
Low 2
0.0000644
*
High 2
Low 2
0.000387557
*
0.0000644
*
*
*
0.0000009
0.0000000002
*
0.0000009
0.0000000002
*
1 and 2 are indication of separate sampling dates
Comparison of densities by dates (t-test, P= 0.05 n ≈ 15)
High density plots have significantly more carbon input than low density plots.
Carbon fixation also increases temporally.
8/21/2010
9/18/2010
High Density Quadrat Comparison PI
450
350
300
250
200
8/21/2010
150
9/18/2010
100
50
1&2&3&4
1&3&4
1&2&4
1&2&3
1&4
1&3
1&2
4
3
2
1
0
Symbionts
Symbionts
450
400
350
300
250
200
150
100
50
0
0 Diopatra
1 Gracillaria
2 Illyanassa
3 Ulva
4 Obelia
5/1/2010
Symbionts
1&2&3&4
1&3&4
1&2&4
1&2&3
1&4
1&3
1&2
4
3
2
1
0
6/12/2010
High Density Quadrat Comparison
HHI
Symbiont quantity
Low Density Quadrat Comparison
HHI
Symbiont Quantity
0 Diopatra
1 Gracillaria
2 Illyanassa
3 Ulva
4 Obelia
400
Symbiont Quantity
0 Diopatra
1 Gracillaria
2 Illyanassa
3 Ulva
4 Obelia
450
400
350
300
250
200
150
100
50
0
0
Symbiont Quantity
Low Density Quadrat Comparison
PI
450
400
350
300
250
200
150
100
50
0
0 Diopatra
1 Gracillaria
2 Illyanassa
3 Ulva
4 Obelia
5/1/2010
6/12/2010
Symbionts
Conclusion
 There is a significant spatial difference between high and low
density plots that is most likely related to quantity of Diopatra
cuprea tube caps that are available for attachment. This is
most likely related to inundation periods.
 There is a significant temporal difference between low
density plots that is most likely related to the growth cycle of
Gracilaria vermiculophylla.
 There are significant spatial and temporal increases in carbon
fixation that is most likely related to its increased growth in
the lower intertidal zone and it’s summer temporal growth
pattern.
Discussion
 The significant spatial increase in carbon fixation is most likely related to the significant
increase in spatial difference between high and low density plots. Gracialaria is spreading
rapidly over these two areas and greatly increasing it’s coverage density and mass. Areas which
before were not covered at all by any symbiot are now completely covered by Gracilaria,
leading to an increase in carbon fixation. The significant temporal increase in carbon fixation
is most likely related to the summer growth period of Gracilaria as well. As plumes become
larger they have greater mass leading to an increase in carbon fixation when this mass is
dislodged from its host.
 The significant temporal difference observed between low density plots is most likely related
to the summer growth pattern of Gracilaria. Most macroalgea experience a higher growth
period during the summer, from an increase in light availability and warmer temperatures in
the summer than in the winter. This leads to greater plume sizes and higher attachment rates.
The sampling at PI showed no significant temporal difference between high density plots but I
believe this was due to the size of the mass upon the first sampling. The area was already so
densely covered that there was no way to increase coverage. The lack of a significant
difference spatially from the second sampling I believe is because the high and low density
areas both had a great amount of coverage. Quadrats only varied by a small amount of tube
attachment, the low density areas were almost as densely covered as the high density areas.
 The significant spatial difference between high and low density plots is most likely related
to tube availability. High density areas have more Diopatra tubes available for attachment.
The lower intertidal zone which is the higher density area experiences longer inundation
periods. This may lead to better and longer feeding periods for the Diopatra. This area also
does not receive the high wave action that the higher intertidal zone area in which is the
lower density area. This increase in hydro dynamic forces may be removing tube caps more
frequently than the low density area leading to an even greater reduction in Diopatra
population there fore reducing the number of Gracilaria plumes.
Works Cited
 Kaiser, M. et al. (2005) Marine Ecology: Processes, Systems, and Impacts. Oxford.
Future Studies
 Hydro dynamic scouring and effects from Gracilaria.
 Is Gracilaria acting as a refuge for other organisms?
 Further interactions between Gracilaria and Diopatra.
High Density Quadrat
Quadrat Sampling
PI Sampling
HHI Sampling
Port Royal
Sound
Current Scouring Erosion
Large Gracilaria Plume
High Density
Low Density
Diopatra Tubes with Attached Gracilaria
on an Intertidal Mudflat on Hilton Head Island
Ulva and Gracilaria Attached to DiopatraTubes
Obelia Attached
to DiopatraTubes
Methods
 Taking a shower
 Homework:
 create a detailed procedure for anything you choose
 ex: making a sandwich, washing a car, etc.