The rocky intertidal is one of the most rich and diverse
habitats for marine invertebrates and it is by far my favorite. Carmet Beach on
the Sonoma County coastline is not only home to beautiful views but to many
marine invertebrate species. The beach has two sandy shores (North and South),
both, which have a rocky intertidal habitat. I have previously explored the
south Carmet Beach rocky intertidal although in this particular case I was able
to expand my knowledge and examine the northern habitat.
One species that I came across that I am also
very familiar with is the barnacle Chthamalus
fissus. These invertebrates are taxonomically apart of the phylum
Arthropoda, subphylum Mandibulata, superclass Crustacea, and class Cirripedia.
To many people they are the hard shelled things attached to rocks that hurt
your feet when barefoot in the rocky intertidal, but there is a lot more to
this invertebrate than meets the eye. C. fissus
are distributed along the western coastline of California from Baja to Bodega Bay. They have a unique life cycle
in which its larval stage is planktonic, and as adults, they attach to rocks
and remain sessile for the rest of their life. There they live, feed, and
reproduce. After fertilization, the egg hatches into a planktonic form called a
nauplius. This form suspension feeds on
phytoplankton and goes through six stages of growth. Next, this larvae molts into a planktonic
cyprid. This stage is non-feeding and
will look for a suitable habitat and substrate to settle and metamorphosize
into an adult barnacle by developing six calcareous plates around its soft
body. What is most unique to me about barnacles is that when submerged, the
marine arthropod living inside the tough exterior shell has feeding legs known
as cirri that protrude out and capture food. I have been exposed to barnacles
throughout my childhood and never knew there was such a beautiful, complex
invertebrate living inside the shells seen in the rocky intertidal since they
are rarely seen submerged.
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| Barnacle |
Another marine invertebrate that
caught my attention and peaked my interest was a hermit crab that was living
inside the shell of the marine gastropod black turban snail (Tegula funebralis). I am fairly familiar
with black turban snails so when I noticed a familiar shell moving too quickly
for its species I decided to take a closer look. After examining the hermit
crab I discovered inside the shell and doing some research I believe that the
crab I spotted is of the genus Pagurus,
which is native to the North American west coast. According to the Monetary Bay
Aquarium, this species of decapod commonly found in the rocky intertidal is a
common inhabitant of abandoned black turban snail shells. When researching this genus, I came across an
article that I found interesting and related to my current biology travels.
Researchers in Japan studied the male mate choice in the hermit crab species Pagurus Nigrofascia. They discovered
that when given the choice of female mates, males will choose the female that
requires the least time to molt. Not only do they want the fastest molting, but
males that have chose quickly molting females will defend these females longer
and have a higher probability of winning against intruding hermit crabs. This
relates to what I have learned about male-to-male combat and mate choice in
evolution where males are inclined to choose females that can produce the most
offspring in the shortest amount of time. Females generally look for genetic
quality where males are merely concerned with the quantity of offspring they
can produce.
The diversity of the rocky
intertidal is truly amazing and there is so much that can be learned from such
an easily accessibility. I think it is important for the community to be
involved and learn about these diverse habitats through sites such as
inaturalist.org and community conservation efforts. When the community is knowledgeable
about invertebrates and their habitats, they are more inclined to protect them.
Refrences
Lee, S.
(2015) Phylum Arthropoda. Biology 322 Lecture October 29, 2015. Sonoma State
University.
Menge, B.
, Foley, M. , Pamplin, J. , Murphy, G. , &
Pennington, C. (2010). Supply-side ecology, barnacle recruitment, and
rocky intertidal community dynamics: Do settlement surface and limpet
disturbance matter?. Journal of Experimental Marine Biology and Ecology, 392(1),
160-175.
Suzuki, Y.
, Yasuda, C. , Takeshita, F. , & Wada, S. (2012). Male mate
choice and male–male competition in the hermit crab pagurus nigrofascia:
Importance of female quality. Marine Biology, 159(9),
1991-1996.
