BIO 362 Lab
Fouling Communities
Pre-lab Assignment – Fouling Communities
Name: _____________________________________
850_____________________________
Date: ______________________________________
All pre-labs need to be completed prior to coming to lab. You will hand these in to your TA before
class. If you don’t complete the pre-lab assignment then you will NOT be allowed to participate that
week's lab/field trip and you will receive a zero grade for that particular lab.
Please provide brief answers or calculations to the following questions in the space provided. You
should read Ch. 11-12 in Levinton prior to arriving in lab.
1. What two components of diversity does the Shannon-Weiner index measure? Explain how they are
different.
2. How do the three major seaweed groups (Rhodophyta, Phaeophyta, and Chlorophyta) differ in
photosynthetic pigment, photosynthate storage medium, and cell wall composition?
3. What are the two basic body plans of cnidarians? Which one is exhibited by Anthozoans such as
anemones?
4. What is a lophophore? What group possesses it?
5. What marine invertebrate group is most closely related (phylogenetically) to vertebrates?
BIO 362 Lab
Fouling Communities
Bio 362 – Fouling Communities Lab
Objectives
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Become familiar with common members of fouling communities
Compare and contrast communities in intertidal and subtidal environments
Use statistical methods to quantify differences in biodiversity between communities
Procedure
1. On the piling just above the floating dock place the small sampling quadrat over an area (above
the water line) and identify and count all the organisms present. Pick an area that is
undisturbed. These organisms can be counted in situ. Also be sure to collect a few barnacles or
any other organisms in a separate bucket for later examination in the lab aquaria.
2. On the floating dock just below the water place the small sampling quadrat against the plastic
float and carefully use the paint scrapers to remove everything inside the quadrat. Use the dip
nets to collect the falling organisms. Place these in a bucket with enough sea water to cover
them. We will take these back to the lab.
3. Back in the classroom, sort through the buckets. Place organisms into aquaria and wait several
minutes to allow epifaunal organisms to emerge. Identify and count all the organisms present in
the sample.
4. At the end of class type your species enumeration data from both sample sites into the class
spreadsheet. This will be sent to you after class. Use the pooled class data to calculate the
Shannon index of diversity (H’) for each sample site (see next page). Your instructor will show
you how to use a t-test to see if the diversity of organisms is statistically different between the
intertidal and subtidal habitats. Your instructor will also show you how to create a frequency
histogram for your data.
BIO 362 Lab
Fouling Communities
From your abundance data for each sub-sample, you will need to estimate diversity. In this case we
are interested in the diversity of the groups counted in the data sheet. Diversity is comprised of two
elements. First there is the total number of types of groups in the set (richness). Then there is the
relative abundance of each group (evenness). The Shannon-Wiener index (H’) and the antilogarithm
of H’ (exp H’) takes both these facets of diversity and combines them into one measure for each
sub-sample, by weighting the abundance of a group as well as its presence in the sample. A rare
group will make a smaller contribution than a common group to the index. The formula is as follows
H’ =∑ pi/pT*ln(pi/pT)
where H’ is the Shannon-Wiener Diversity index, pi is the number of individual of species i, pT is the
total number of individuals of all species, and ln is the natural logarithm (log base e). The summation
is taken over all species, i = 1, 2, … S.
Example:
Table 1.0. Counts of epifauna in a sub-sample (in your data you will classify to lower
organizational levels)
Number in sample
Relative abundance
Tunicate
8
8/16 = 0.50
Caprellid
4
4/16 = 0.25
Gammarid
2
2/16 = 0.125
Bryozoan
2
2/16 = 0.125
Total
16
1.00
Using these data, the Shannon-Wiener Index is calculated as follows:
H’ = - [0.50 ln(0.50) + 0.25 ln(0.25) + 0.125 ln(0.125) + 0.125 ln(0.125)]= 1.21
Note: Groups that are absent from a sample are not used in the calculation. Example: if
there were no Gastrotrichs in the sample, calculate H’ based on a total sample that
includes Nematodes, Copepods, and Polychaetes.
When the Shannon-Wiener Index is expressed as the inverse logarithm
e(H’) (in excel use =exp(H’))
it has the following useful properties:
-It can range from 1 to the species richness (S).
-It is equal to species richness if all species are equally represented.
BIO 362 Lab
Fouling Communities
-For our example above: e 1.21 = 3.36
Assignment
(use this document as a template; complete all calculations and graphs in Excel and paste the figures
into this document)
1. The organisms in the intertidal face a suite of different biotic and abiotic factors compared to
those in the subtidal. Name at least 4 differences between these two tidal zones. (4 points)
2. Is Shannon-Weiner diversity statistically different between the two habitats (use the statistical
techniques you learned to answer this question). Please report the mean S-W results as well as
the t-statistics, degrees of freedom, and p-value for the t-test. If they are different why do you
think this is so? (4 points)
3. Describe the trophic level and feeding mode of 4 organisms you looked at today. (eg.
Crassostrea virginica – Eastern oyster, Primary consumer, suspension feeder). (8 points)
4. Create a frequency histogram of the species present in each habitat and paste below. (4 points)
BIO 362 Lab
Fouling Communities
Common species in the fouling community
CHLOROPHYTA
Ulva sp.
RHODOPHYTA
PHAEOPHYTA
PORIFERA
Class Demospongiae
Aplysilla longispina or A. sulfurei – sulfur sponge
CNIDARIA
Class Anthozoa
Aiptasia pallida – pale or brown anemone
Astrangia danae – star coral or Northern cup coral
Class Hydrozoa
Halocordyle disticha – feather hydroid
Eudendrium carneum – primary food source for sea spiders
BRYOZOA
Class Gymmnolaemata
Bugula neritina – common or bushy bugula
Schizoporella unicornis – “orange crust”
MOLLUSCA
Class Bivalvia
Modiolus americanus – tulip mussel
Crassostrea virginica – Eastern oyster
ARTHROPODA
Class Cirripedia
Balanus amphitrite – striped barnacle (only species that my groups found)
Class Malacostraca
Palaemonetes vulgaris – grass shrimp
Panopeus herbstii – common mud crab
Pilumnus sayi – hairy crab
Class Pycnogonida
Anoplodactylus lentus – lentil or black sea spider
ECHINODERMATA
Class Echinoidea
Arbacia punctulata – purple sea urchin
CHORDATA
Class Ascidiacea
Styela plicata – pleated sea squirt or rough sea squirt
Symplegma rubra – red/orange colonial tunicate (growing over some dead barnacles)