Red algae

Receiving their red color from pigments called phycobiliproteins, red algae is a plant-like protist found throughout the tidal zones and within deeper waters. They are photosynthetic autotrophs that grow throughout many regions of the world (Stiller and Hall, 1997)

Focusing on Laguna Beach, California, red algae is one of the more dominant organisms in the tides, taking up about 23.6 percent of the tidal zones. Only the holdfast and very bottom of the stipe is occupying space on rocks while the rest of the red algae flows freely above with the water. Organisms that are also abundant in these tides are mussels, lipids, and chitons. Mussels are suspended feeders, taking up the most space on the surface of the rocks, while the limpets and chitons are grazers and because of their smaller size, could be found on the mussels or rocks.

I suspect that due to their small size and diet, red algae will have some negative correlation with the limpets. Limpets feed on the algae that grow on rocks and red algae often grow abundantly enough to cover the surface of the water. This will block the sun and prevent optimal growth of algae on the rocks, limiting limpet resources. I expect the same outcome for chitons but less of an effect because chitons have an alternative food source. As for mussels, they are filter feeders and eat free-floating organisms such as plankton. Their resources cannot be diminished by the presence of algae, therefore, no significant correlation is expected. Lastly, since water is essential for the survival of the red algae. Having a larger area submerged in water will result in a higher red algae percentage.

Dennis J. Russell from Seattle Pacific University studied Acanthophora spicifera, an invasive red algae introduced to Oahu, Hawaii in the 1950s. In Hawaii, Acantho­phora colonized the reefs in zones occupied by Valonia ventricosa. Russell hypothesized that A. spicifera forms associations with Laurencia and Hypnea species in Hawaii as well as competes, displaces, or replaces them on the reef (Russel, 1992).

I hypothesize that red algae found in Laguna Beach may not disturb the other organisms as Acanthophora spicifera does, but there is a correlation between the algae and other organisms, affecting the abundance and dispersion.

Materials & Methods

Beginning the study, a 50-meter baseline transect was placed through the upper, middle, and lower tidal zone of laguna beach. Starting at the zero meter point of the baseline transect, 25-foot perpendicular transects were placed every two meters. A square square-foot plot was used to determine the section to sample from on the perpendicular transects, using the random number table to determine where the plot would be placed. To keep the data consistent the plot needed to be placed in the same position throughout the experiment. With the plot on the ocean side of the transect, the corner was placed at the given number. Next, the plot number, percent of plot underwater, red algae, mussels, and the number of individual lipids and chitons were all recorded. A cap was used as a guiding tool to give an idea of the percentage coverage of each organism. This was repeated four times at each of the perpendicular transects.

Using excel, the data from each of the of the perpendicular transects were put into one document for calculations. Each organism along with the water percentage was put into separate categories to calculate each of the averages. With the help of a Stat Cat provided by Cal Poly Pomona professor, I was able to calculate the correlation coefficient and P value which told me whether my data was in favor of my hypothesis. With the given calculator each of the organisms was compared the red algae data determining the effects it had on each.

Conducting a similar experiment, Eric Conklin and Jennifer Smith from the Hawaii Institute of Marine Biology, focused on the benthic zone and a larger species of red algae called Kappaphycus spp., using two transect lines 15 meters apart spanning 30 meters. Their focus was not on the tides but the reef flat. Experimenting on red algaes effects on the neighbouring but over a longer time span and removing sections of red algae to observe regrowth of red algae or new growth of different organisms (Conklin and Smith, 2005).

Results

Figure 1 shows the average abundance of red algae as you move along the transect. The slope shown above is .9254 and the coefficient of determination is 0.4717.

Sampling from the twenty-five different transects there was no significant correlation found between red algae and the California mussels (r=-0.17, p=0.06), or red algae and water cover (r=0.16, p=0.12). There was, however, a significant negative correlation between red algae and limpets (r=-0.35, p=0.0003), red algae and chitons (r=-0.21, p=0.02). Between the average red algae abundance and baseline distance, there was a significant positive relationship (F=21.43, p=.00011). Lastly, 47% of the abundance of red algae can be explained by the distance from the baseline (r=0.47)

Discussion

The results mostly prove my hypothesis correct. The relationship between the red algae had no mentionable effect. There was a negative effect between the red algae and limpets and a negative effect between red algae and chiton meaning that red algae negatively impacted the growth and survival of the organisms. Where my hypothesis was disproved the correlation between the algae and the water. I assumed the water had a positive effect on red algae, when in fact there is no significant correlation between the two.

It’s not certain my reasoning for the correlations is correct but given the outcome of the results, it is possible. The results of Dennis J. Russell included finding Acanthophora and L. nidifica attached to the substratum and to each other at the same time. Often all three species were found growing together, A. spicifera and L. nidi­fica tangled and fused to each other with H. cervicornis epiphytic in both their branches (Russell, 1992). This implies the specimens were together on the reef when they were collected.

The experiment from Eric Conklin and Jennifer Smith had mixed results, populations of Kappaphycus spp. increased or decreased in abundance over time. Coral cover across the bay was variable and appeared to be increasing at some of the sites while decreasing at others. D. cavernosa and G. salicornia decreased in abundance at some sites but overall remained relatively constant (Conklin and Smith, 2005)

The experiment was short and if there were more factors included it could have been a more successful experiment. I feel that it was rushed experiment and if given more information about the process of the experiment beforehand and more time at the experiment site, the outcome would be more accurate and informational.

Within one environment a large variety of species can be found. Red algae may be the most abundant organism in laguna beach tides but that does not mean it affects the rest of the organisms negatively. Multiple organisms can co-exist and may even benefit from the organisms around it. Red algae were however found to negatively affect some, not positively affecting others, and retain neutral to others.

Literature Cited

1. Conklin, Eric J, and Jennifer Smith.
2. “Abundance and Spread of the Invasive Red Algae, Kappaphycus Spp., in Kane’Ohe Bay, Hawai’i and an Experimental Assessment of Management Options.” SpringerLink, 2005.
3. Russell, Dennis J. The Ecological Invasion of Hawaiian Reefs by Two Marine
4. Red Algae, Acanthophora Spicifera (Vahl) Boerg. and Hypnea Musciformis (Wulfen) J. Ag., and
5. Their Association with Two Native Species, Laurencia Nidifica J. Ag. and Hypnea Cervicornis J. Ag. 1992.
6. Stiller, John W, and Benjamin D Hall. “The Origin of Red Algae: Implications for Plastid Evolution.” PMC, NCBI, 29 Apr. 1997,