A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town

Simple item page
dc.contributor.advisorBolton, John Jen_ZA
dc.contributor.advisorAnderson, Robert Jen_ZA
dc.contributor.authorRobertson-Andersson, Deborahen_ZA
dc.date.accessioned2017-11-07T09:59:44Z
dc.date.available2017-11-07T09:59:44Z
dc.date.issued2000en_ZA
dc.date.updated2017-02-22T12:49:02Z
dc.description.abstractFive years have passed since the Two Oceans Aquarium, Cape Town, opened its doors for the first time in November 1995. Since then, a seaweed community has established itself in the Kelp tank. The seaweeds were brought in as either epiphytes on mature macro algae or as epiphytes on boulders that were placed on the floor of the tank. Thus, the community in the tank can be assumed to have established itself naturally. This study looked at the extent of the species diversity, zonation patterns in the tank (with particular reference to wall orientation), depth substrate type, plane (i.e. vertical or horizontal surfaces) and species distribution with depth. This was done by placing quadrats in transects down each wall and noting the percentage cover of each species. Quadrat depth, substrate type, wall orientation, and plane were noted. The percentage cover values as well as the environmental data were entered into CANOCO, an ordination programme for windows. Ordination showed that the tank was essentially a homogeneous environment with no difference in species distribution with regard to wall orientation, depth, substrate type, or plane. It was noted that self-seeded Ecklonia maxima were very unhealthy, small, deformed and had many epiphytes, with the exception of three plants that were growing under the plunger. From this it was concluded that water motion, and not light or nutrients, was limiting in the tank. Schimmelmannia elegans was found growing in the kelp tank. It had never been described as growing in South Africa previously. One theory was that the increased daylight length in the tank, caused by the fact that lights over the tank were often left on for extended periods, triggered a photoperiodic reproductive cue from the crustose phase (which was assumed to be growing unrecorded on the Cape Peninsular) for the sporophyte to grow. However, daylight length in the Kelp tank and Tristan da Cunha (where it was first recorded as growing) were the same so that theory was discarded. Another theory was that the algae was introduced into the tank in some way. This, however requires further investigation. Environmental conditions in the tank were investigated using aquarium records. Light intensity and duration, water temperature, pH, salinity, dissolved oxygen concentration were all found to be optimal for photosynthesis and growth to occur. Water motion was seen as the only limiting factor for photosynthesis and growth as it also has an effect on nutrient uptake. Grazer intensity was also examined. It was found that grazing by fish was stable; however, grazing by invertebrates and particularly mesa-herbivores could be increased, by adding more of them into the tank. It was found that with light being left on for functions there was no real seasonal change in light duration and this may be a problem for seaweeds that experience seasonal growth as they are missing seasonal cues. A management option of having a strictly controlled 11 hours of daylight during a winter month was proposed as a solution. This study is a good reference point for future work to be done on seaweed succession in the Kelp tank.en_ZA
dc.identifier.apacitationRobertson-Andersson, D. (2000). <i>A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/26029en_ZA
dc.identifier.chicagocitationRobertson-Andersson, Deborah. <i>"A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2000. http://hdl.handle.net/11427/26029en_ZA
dc.identifier.citationRobertson-Andersson, D. 2000. A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Robertson-Andersson, Deborah AB - Five years have passed since the Two Oceans Aquarium, Cape Town, opened its doors for the first time in November 1995. Since then, a seaweed community has established itself in the Kelp tank. The seaweeds were brought in as either epiphytes on mature macro algae or as epiphytes on boulders that were placed on the floor of the tank. Thus, the community in the tank can be assumed to have established itself naturally. This study looked at the extent of the species diversity, zonation patterns in the tank (with particular reference to wall orientation), depth substrate type, plane (i.e. vertical or horizontal surfaces) and species distribution with depth. This was done by placing quadrats in transects down each wall and noting the percentage cover of each species. Quadrat depth, substrate type, wall orientation, and plane were noted. The percentage cover values as well as the environmental data were entered into CANOCO, an ordination programme for windows. Ordination showed that the tank was essentially a homogeneous environment with no difference in species distribution with regard to wall orientation, depth, substrate type, or plane. It was noted that self-seeded Ecklonia maxima were very unhealthy, small, deformed and had many epiphytes, with the exception of three plants that were growing under the plunger. From this it was concluded that water motion, and not light or nutrients, was limiting in the tank. Schimmelmannia elegans was found growing in the kelp tank. It had never been described as growing in South Africa previously. One theory was that the increased daylight length in the tank, caused by the fact that lights over the tank were often left on for extended periods, triggered a photoperiodic reproductive cue from the crustose phase (which was assumed to be growing unrecorded on the Cape Peninsular) for the sporophyte to grow. However, daylight length in the Kelp tank and Tristan da Cunha (where it was first recorded as growing) were the same so that theory was discarded. Another theory was that the algae was introduced into the tank in some way. This, however requires further investigation. Environmental conditions in the tank were investigated using aquarium records. Light intensity and duration, water temperature, pH, salinity, dissolved oxygen concentration were all found to be optimal for photosynthesis and growth to occur. Water motion was seen as the only limiting factor for photosynthesis and growth as it also has an effect on nutrient uptake. Grazer intensity was also examined. It was found that grazing by fish was stable; however, grazing by invertebrates and particularly mesa-herbivores could be increased, by adding more of them into the tank. It was found that with light being left on for functions there was no real seasonal change in light duration and this may be a problem for seaweeds that experience seasonal growth as they are missing seasonal cues. A management option of having a strictly controlled 11 hours of daylight during a winter month was proposed as a solution. This study is a good reference point for future work to be done on seaweed succession in the Kelp tank. DA - 2000 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2000 T1 - A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town TI - A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town UR - http://hdl.handle.net/11427/26029 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/26029
dc.identifier.vancouvercitationRobertson-Andersson D. A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2000 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/26029en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBotanyen_ZA
dc.titleA study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Townen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_ZA
uct.type.filetype
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Robertson_Andersson_A_study_distribution_2000_1.pdf
Size:
10.95 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.72 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Other Theses