What is the Ecology of a Holdfast?
by
Bailey and Madi
Map of Howland's Landing
Ecology
of a Holdfast
On our eighth grade field trip, we traveled to Catalina Island just off
the coast of California. The camp that we stayed at was called CELP; Catalina
Island Leadership Program. This program helped us learn about the delicate
eco system in Catalina. This includes kelp. Kelp is a plant that grows
in cold nutrient enriched water. At Catalina island we participated in
numerous activities pertaining to the ecosystem, nature, and the marine
biology of the California coast. Our school had the opportunity to research
while kayaking and snorkeling in Emerald Bay, Bird rock, and the dock
area by Howland’s landing. We collected data on turbidity, salinity,
depth, temperature, fish counts, etc. What we found will be helpful to
scientists around the globe.
The main question that we revolved our studies was: What is the ecology
of the holdfast of a kelp plant. We wanted to zoom in and learn practically
everything about it. Such as what it is, what it does, where it grows,
and why it grows there. Through snorkeling we experienced it first hand;
we researched it, and took gps points while kayaking. We split our project
up to make our research more indepth. Madi will be explaining what lives
in a holdfast and I, Bailey will show what it is and what it does.
Kelp forests grow along rocky coastlines in shallow depths. Kelps are
types of brown algae, which hold on to the rocky bottom with root-like
structures called holdfasts. Although holdfast may appear to be like a
type of “root” they actually would not be considered one because
they do not performs the same jobs. A root in a terrestrial forest by
definition sucks up nutrients while kelp holdfasts have nothing to with
nutrients. They serve as an anchor to hold and attach the kelp to the
rocks on the sea floor. As Madi said before much of the kelp plants were
gone when we visited because they died out or storms ripped them of the
holdfasts. The holdfasts survived through and we could still see them.
As a holdfast grows more and more branches cover up the old ones and through
time it becomes a cone shape. Animals and inhabitants of the holdfast
over time eat the inner, older layers. The end of the holdfasts life comes
when it gets too weak and may be ripped off the ocean floor. Seeing a
giant kelp plant you most likely have no idea it was once a diploid or
in other words a pair of two chromosomes. On every kelp plant there are
male and female spores in its reproductive blades. After its fertilized
half of it begins to grow a holdfast and the other a branch. It can only
grow if it lands on a clean rock or a rock that has been cleaned by a
sea enchain or some other animal.
The methods that we used to examine the holdfast were very simple. We
used the GIS mapping devices to mark points of all the kelp plants we
saw. We had previously researched the global affects of the “El
Nino” which has an enormous affect on the ecology of the Pacific
coast. We found that since it is an El Nino season right now, kelp was
extremely scarce, as well as fish that might dwell in the plant. Since
the kelp is dying because the waters of the El Niño are so hot,
the dead holdfast releases its anchorage to the rock and drifts along
the sandy bottom. Even though kelp was scarce, holdfasts were not. We
found many on the sea floor; one was covered in worm casings. On the map
layers displayed, it shows the different years of data collections of
kelp. The plants may have been abundant a few years ago, but the current
El Nino has caused the population to wither exceedingly. With the kelp
population dropping, so does the sea urchin, the bryozoans, sea snails
and small fish such as blue banded gobys and senioritas. Everything is
connected, and since kelp is very important to other creature in the ocean,
not just for food, but for shelter they most go to plants simplair to
kelp and their populations decrease.
