1. Species
diversity
and
association
in
the
rocky
intertidal
zone
of
Mount
Hope
Bay
Benjamin
Gibson
Roger
Williams
University
Introduction
Narragansett
Bay
is
a
predominantly
rocky-­‐intertidal
coastline
inhabited
by
an
array
of
invertebrate
species.
The
rocky
intertidal
zone
is
strongly
affected
by
the
forces
of
nature.
The
wind
waves,
tides,
and
currents
all
play
a
factor
in
the
organisms
that
call
this
harsh
environment
their
home.
The
shoreline
area
presents
marine
organisms
with
the
problems
of
exposure,
temperature
fluctuations,
and
salinity
fluctuations.
In
turn,
this
provides
terrestrial
organisms
with
the
problems
of
submersion,
desiccation,
and
high
salinity.
Any
of
the
organisms
that
attempt
to
colonize
in
the
rocky
intertidal
zone
have
to
be
outfitted
with
survival
traits
specific
to
this
environment.
Space
is
also
a
limiting
factor
in
the
rocky
intertidal
zone;
organisms
have
to
congregate
in
the
areas
resistant
to
the
constant
wave
and
tidal
action.
The
high
energy
dynamics
of
the
rocky-­‐intertidal
make
it
a
difficult
place
for
organisms
to
grown
within
the
water
column.
Organisms
that
live
within
the
rocky
intertidal
zone
have
to
adjust
to
the
physical
component
of
wave
action,
salinity,
and
temperature
changes,
but
also
need
to
compete
for
space
within
the
zone.
With
space
being
a
limiting
factor
within
the
eulittoral
zone,
and
predation
in
the
splash
zone,
it
is
difficult
for
any
organism
to
live
or
colonize
the
intertidal
area.
Materials
and
Methods
Scientific
tools
that
were
utilized:
• Area
Measurements:
Quadrants
measuring
1X1
meter(s),
tape
measure
• Identification:
Field
Guides
The
research
was
conducted
in
an
area
of
Mt.
Hope
Bay,
the
northeastern
section
of
Narragansett
Bay,
Rhode
Island.
Specifically
targeting
the
area
to
the
north
and
the
south
of
the
Roger
Williams
University
Learning
Platform,
The
tidal
zone
was
measured
at
the
lowest
tide
which
insures
that
each
of
the
three
zones
is
equally
represented.
Each
group
surveys
a
portion
of
the
specific
intertidal
zone
with
a
quadrant,
a
1m2
area
tool
used
to
help
quantify
species
in
similar
experiments.
Each
group
surveys
a
lower,
middle,
and
upper
tidal
area
and
records
the
abundance
of
species
and
population
at
each
of
the
sections.
The
areas
were
sampled
on
September
8th
,
2014,
with
overcast
weather
conditions
and
at
the
peak
of
low
tide.
All
produced
data
was
then
loaded
into
a
spreadsheet
(Excel).
Then
the
data
was
analyzed
using
Excel
to
find
the
Coles
coefficient
of
association
and
a
linear
regression
line
and
the
r2
value.
Both
of
these
tests
were
conducted
in
Excel.

2. Results:
Fig.
1
Comparison
between
groups
of
the
number
of
individuals
between
the
three
zones
Fig.
2
Comparison
of
the
species
diversity,
using
number
of
species
in
each
of
the
three
intertidal
zones.
R²
=
0.61856
0
50
100
150
200
250
300
350
400
450
Upper
Middle
Lower
Number
of
individuals
Interadal
zones
Group
1
Group
2
Group
3
Group
4
Linear
(Regression)
0
2
4
6
8
10
12
14
16
Upper
Middle
Lower
Number
of
Species
Interadal
Zone
Group
1
Group
2
Group
3
Group
4

3.
The
diversity
indices
of
the
rocky
intertidal
zone
down
by
the
learning
platform
at
Roger
Williams
University,
changed
with
distance
from
the
water.
Table
2
shows
the
relationship
between
species
diversity
and
distance
from
the
water.
The
three
zones
are:
the
upper
zone,
also
considered
the
splash
zone,
is
the
furthest
from
the
water.
The
middle
zone,
or
the
eulittoral
zone,
is
the
midpoint
between
the
upper
and
lower
zone.
Lastly,
the
lower
zone,
also
known
as
the
lower
eulittoral
zone,
is
almost
always
submerged
in
seawater.
Table
1
outlines
the
species
seen
at
each
of
the
three
zones,
and
it
can
be
stated
that
the
most
species
are
in
the
lower
zone.
However,
there
are
several
species
that
are
found
at
both
extremes,
one
such
example
is
the
periwinkle.
Figure
1
shows
the
number
of
individuals
that
are
present
in
each
zone,
with
an
r2
value
of
0.62
and
a
regression
line
showing
this
value.
Figure
2
is
comparing
the
number
of
species
at
each
of
the
zones,
compared
by
the
groups.
Another
aspect
of
a
diversity
study
is
calculating
Cole’s
Coefficient
of
Association
(Ca)
which
is
outlined
in
table
3.
Taking
a
predator
and
known
prey
and
calculating
Ca
yields
how
likely
of
an
association
is
present
in
our
data.
Discussion
As
seen
in
figure
1’s
regression
line,
there
is
an
r2
value
of
0.62,
which
indicates
that
62%
of
the
total
variance
in
the
number
of
individuals
is
explained
by
each
zone.
Figure
2
shows
the
number
of
species
discovered
by
each
group,
separated
by
zones.
Table
1
is
data
from
group
2,
which
outlines
the
species
diversity
at
each
of
the
different
zones.
The
most
diverse
zone
is
the
lower
zone
which
has
been
proven
by
both
studies
and
theory.
Not
only
was
the
lower
zone
the
most
diverse,
but
the
types
of
animals
there
were
ones
that
would
not
thrive
in
the
intense
conditions
that
the
middle
and
upper
zones
feature
during
low
tide.
These
organisms
included
algae
of
all
phylums,
polychaete
worms,
and
other
soft
bodied
species.
The
organisms
that
populated
the
middle
and
upper
zones
were
mostly
gastropods
and
crustaceans;
Mean
n(n-­‐1)
Mean
N(N-­‐1)
Mean
Diversity
Index
Upper
zone
7525.5
19430
0.39
Middle
zone
12517.5
37754
0.33
Lower
zone
17573
47841
0.37
Table
2.
Averaging
of
each
group’s
data,
the
approximate
diversity
index
of
the
area
can
be
found.
Species
Upper
Middle
Lower
Asian
Shore
Crab
3
9
11
Green
Crab
0
1
0
Barnacles
36
117
219
Polychaete
0
0
1
Beach
Flea
1
0
10
Mud
Snails
0
33
60
Tube
worms
0
0
9
Slipper
Shells
0
0
18
Mussels
0
0
19
Quahog
0
0
1
Oyster
drills
0
0
2
Periwinkles
6
15
11
Red
Algae
6
13
13
Green
Algae
4
8
8
Brown
Algae
0
3
5
Table
1.
Species
diversity
for
Group
2
at
the
upper,
middle,
and
lower
zones.

4. gastropods
and
barnacles
are
able
to
withstand
the
harsh
conditions
of
the
middle
and
upper
zones
due
to
their
ability
to
reduce
their
risks
of
desiccation.
They
do
this
by
storing
water
and
closing
themselves
off,
through
the
use
of
either
an
operculum
or
plates.
Table
2
averages
and
summarizes
the
three
zones,
using
diversity
indices.
Averaging
the
sum
of
n(n-­‐1)
and
N(N-­‐1)
across
all
groups
supplied
the
average
diversity
index
for
each
pf
the
three
zones.
The
diversity
indices
were
all
relatively
close
to
each
other,
however
with
a
big
enough
sample
size,
there
would
be
a
notable
difference
between
the
upper,
middle,
and
lower
zones.
For
this
study,
the
diversity
indices
were
not
what
would
we
thought
they
would
be;
the
upper
zone
had
the
highest
diversity
index
of
0.39,
the
middle
had
the
lowest
index
of
0.33,
and
the
lower
zone
had
the
intermediate
diversity
index
of
0.37.
The
lower
zone
is
thought
to
be
the
most
diverse
of
the
three
zones.
Table
3
outlines
Cole’s
Coefficient
of
association
and
how
likely
it
is
that
the
two
species
are
associated
with
each
other.
As
believed
due
to
them
being
related
as
predator
and
prey,
the
periwinkle
and
green
algae
respectively
are
associated
with
a
Ca
value
of
0.52.
This
suggests
that
the
two
are
associated
with
one
another.
This
value
was
calculated
using
the
equation
outlined
in
the
equation
section.
Equation:
𝑪 𝒂 =
( 𝟖 ∗ 𝟐 − 𝟏 ∗ 𝟐 )
𝟖 + 𝟏 ∗ (𝟏 + 𝟐)
Conclusion
The
intertidal
zone
provides
a
difficult
environment
for
terrestrial
and
marine
organisms.
However,
the
data
was
not
supportive
of
the
original
hypothesis
that
it
was
the
lower
intertidal
one
that
would
present
the
largest
species
diversity.
The
middle
intertidal
zone
showed
the
largest
diversity
index
(.38),
and
suggests
that
the
middle
intertidal
is
the
most
species
diverse.
This
resulted
from
differences
in
the
data
analysis
methods
of
the
groups.
The
conducted
study
contained
too
Periwinkles
Present
8
1
2
2
Absent
Present
Absent
Green
Algae
Table
3.
Cole’s
Coefficient
of
association
between
Green
Algae
and
Periwinkles.
8
is
the
number
of
quadrants
where
both
the
green
algae
and
periwinkles
are
present,
1
is
the
number
of
quadrants
where
green
algae
is
absent
but
periwinkles
are
present,
2
on
the
left
is
the
number
of
quadrants
where
green
algae
is
present
but
periwinkles
are
absent,
and
finally
the
2
on
the
right
represents
the
number
of
quadrants
where
both
green
algae
and
periwinkles
are
absent.

5. many
different
data
collection
and
analysis
methods
to
suggest
a
significant
correlation
between
data
and
actual
habitat
diversity
of
the
Mt
Hope
Bay.
To
represent
the
organisms
and
species
diversity
in
the
bay
it
is
important
for
the
collection
methods
to
be
uniform.
Uniform
distances
separating
the
three
intertidal
zones.
Furthermore,
the
collecting
patterns
and
frequencies
require
more
standardization
among
all
groups
so
that
there
is
no
question
of
the
significance
of
the
data.
The
suggestion
that
the
periwinkle
and
green
algae
are
associated
in
the
intertidal
ecosystem
is
evident
in
the
data
collected.
Using
the
Coles
coefficient
it
was
determined
that
the
periwinkles,
being
the
natural
predator
of
various
species
of
green
algae,
are
associated
with
green
algae
in
this
survey.
This
association
correlates
with
the
belief
that
periwinkles
are
predators
of
green
algae.