What Is Coral? A Coral Polyp and Zooxanthellae | Smithsonian Ocean
The most well-known relationship is between zooxanthellae and hermatypic, or reef-forming, corals. In this paper, a closer look at the associations between. In a paper discussing the effects Hurricane Flora had on coral reefs in Jamaica, it was found that some zooxanthellae did in fact reinhabit the. Symbiosis between Zooxanthellae & Corals. By What are Zooxanthellae? on top of the old; Over thousands of years of accumulation, a coral reef is formed.
Like plants, zooxanthellae capture energy from the sun and turn it into food, some of which the coral eats in exchange for protection. Where Do They Live? Smithsonian Institution As you can see in this diagram, the zooxanthellae live within the tissue of their host coral.
The coral polyp itself lives in a cup it built from calcium carbonate; decades of piled up calcium carbonate cups create the reef.
Photo Collection of Dr. Their pink color comes from the zooxanthellae living inside. More about coral reef ecosystems can be found in our Coral Reefs featured story. Horizontal gene transfer and many genetic lineages make up the Symbiodinium species, causing disparity among the clades.
So although there are many Symbiodinium-like species, this idea of clade shuffling seems slightly implausible, because it usually is a matter of Another study focused on the classification of zooxanthellae They isolated compounds that were later identified as toxins that were unique from other dinoflagellates.
The discovery and research into these compounds also supported that the molecules were from the algae and not a result of the host, but it seemed that variation to the host and environment caused the production of different algal metabolites. Many other toxins and compounds were isolated in this study and added significantly to the fact that the metabolism and taxon of zooxanthellae are extremely diverse.
Furthermore, it has been shown that specific Symbiodinium are more tolerant to heat and stress, and perhaps corals adopting these specific algae will be able to survive the temperature changes from global warming and natural disasters Another study found that following bleaching, corals had clade shuffled from C2 to D, because D has a higher densities and photochemical efficiency, resulting in higher thermal tolerance The coral polyps do cellular respiration, thus producing carbon dioxide and water as byproducts.
The zooxanthellae then take up these byproducts to carry out photosynthesis.
- Zooxanthellae and their Symbiotic Relationship with Marine Corals
The products of photosynthesis include sugars, lipids, and oxygen, which the coral polyps thus uptake for growth and cellular respiration, and the cycle continues. The photosynthesis byproducts are more specifically used to make proteins and carbohydrates in order to produce calcium carbonate for the coral to grow. Furthermore, the oxygen is used by the coral to help remove wastes.
This recycling of nutrients in between these symbionts is extremely efficient, resulting in the ability to live in nutrient poor waters. About ninety percent of the material produced by photosynthesis is thought to be used by the coral 6. In terms of disease, the zooxanthellae is commonly the point of attack, rather than the coral itself.
For example, the Montastrae species, which causes Yellow Band Disease, affects the zooxanthellae directly rather than the coral 7. Scientists found that a coral, Acropora, lacked an enzyme needed for cysteine biosynthesis. It thus needed Symbiodinium for the production of this amino acid. The genome size for the zooxanthellae algae is about 1, Mbp while the coral is approximately Mbp: Sure enough, other studies have shown phosphate-linked relationships between these two species.
Zooxanthellae extracted from the Acropora coral had two acid phosphatases P-1 and P The activity of these enzymes shows that perhaps their role is involved in the mobilization of a phosphate storage compound.
The exact role of these enzymes is unknown, but it seems that the symbiotic relationship between coral and zooxanthellae is phosphate limited But together, the coral and zooxanthellae can synthesize twenty amino acids 17 Figure 6.
There is also a relationship between the amount of time the tentacles of the coral spend expanded or contracted and the amount of zooxanthellae present on the coral. In general, there was lower photosynthetic efficiency in the zooxanthellae coral species that has their tentacles expanded only at night than the species with their tentacles constantly expanded. Also, the zooxanthellae density was higher in the continuously expanded tentacle species. These differences were found only in the light however, because when the species were placed in the dark no differences were found.
Thus the light has a relationship with the coral and zooxanthellae, which was assumed because zooxanthellae are photosynthetic organisms. Conclusively, the species with continuously expanded tentacles have dense populations or small tentacles. The findings suggest that small tentacles do not shade the zooxanthellae, thus they are all visible to the light, and that dense populations are necessary to harvest the light.
So the species with these proactive properties expand continuously to collect all the light, while the species with few zooxanthellae only expand at night Another study related the exposure of the coral to oxygen as a means for oxygen radical accumulation in its tissues The O2 concentrations were found to increase by a pH of about 1. Thus causes an increase of oxygen radicals in the coral tissues from the molecular oxygen, and the radicals can destroy cells.
This study found that the anemones with higher chlorophyll, and thus higher Symbiodinium, actually adjusted their protein expression so the fluctuating oxygen concentrations would not be destructive. This is just another example of how the coral changes its innate reactions to adjust for its symbiotic algae Figure 7.
Zooxanthellae and their Symbiotic Relationship with Marine Corals - microbewiki
Movement Furthermore, it was found that the temperate symbiotic sea anemone, Anthropluera balli, incorporates a maternal inheritance of the zooxanthellae because the anemone live in locations of low zooxanthellae algae. It was found that the spawned ova consistently contained zooxanthellae, and were released into the ocean water to become fertilized and grow.
The zooxanthellae was clearly integrated into the life cycle of this particular sea anemone, and was found to localize at one end of the embryo to become integrated within the endoderm, which as mentioned above is where the zooxanthellae live within coral This study brings arise the question of how zooxanthellae disperse among the coral.
Another study discovered that the zooxanthellae can be released by the host in ways such as predation, extrusion, spontaneously, osmotically, or as we know, due to temperature or stress. This particular study proposes another way for zooxanthellae to disperse, through the feces of their predators. Interestingly, photosynthetic rates from the unharmed species were very similar to the rates from the fecal zooxanthellae that made their way through a digestive tract.
Furthermore, the zooxanthellae reinfected sea anemones after their travel through the digestive tract of their predator. This finding showed that predation is an important means by which the zooxanthellae are dispersed among a coral reef History The relationship between Symbiodinium and coral has been known for about fifty years.
Commensalism is a form of symbiosis in which one participant benefits and the other feels no effects at all. Coral Reef ecosystems are teeming with symbiotic relationships. Inside each coral polyp lives a single-celled algae called zooxanthellae. The zooxanthellae capture sunlight and perform photosynthesis, providing oxygen and other nutrients to the coral polyp that aid in its survival.
In turn, the zooxanthellae is provided with the carbon dioxide expelled by the polyp that it needs to undergo photosynthesis.
The presence of the zooxanthellae also provide colored pigments to help protect the coral's white skeleton from sunlight.