Respiration, reef

Patterson, M. R., Sebens, K. P. and Olson, R. R. (1991). In situ measurements of flow effects on primary production and dark respiration in reef corals, Limnol. Oceanogr., 36, 936-948. 

On the other hand, association with more palatable seaweeds may have a negative impact on the chemically defended partner. For example, Halimeda specimens from Conch Reef, Florida Keys, with more than 50% of their thalli covered by Dictyota grow significantly slower than unepiphytized thalli (Beach et al. 2003). This study also verified that epiphytic Dictyota negatively affects metabolic rates of Halimeda tuna in part by shading their thalli, but probably also by chemical means, because the exposure to Dictyota-conditioned water elevated respiration rates in a manner similar to when H. tuna is naturally epiphytized by Dictyota. 

Inhibition of cytochromes of electron transport system can be caused by cyanogenic glycosides, such as amygdalin (Fig. 11.14) in bitter almonds, Prunus amygdalus, linamarin and lotaustralin in clover and birdsfoot trefoil, or dhurrin (Fig. 11.14) in Sorghum vulgare. The potent effect of cyanide on cell respiration has given rise to a recent serious conservation problem. In Southeast Asia, divers stun fish on coral reefs with a blast of cyanide to collect them for the aquarium trade. In the process, many fish are killed and the corals bleached, because their symbionts die (e.g. Payne, 2001). 

Cheshire, A. C., Wilkinson, C. R., et at. (1997). Bathymetric and seasonal changes in photosynthesis and respiration of the phototrophic sponge Phyllospongia lamellose in comparison with respiration by the heterotrophic sponge lanthella basta on Davies Reef, Great Barrier Reef. Marine and Freshwater Research 48, 589—599. 

Smith, S.V., 1973. Carbon dioxide dynamics A record of organic carbon production, respiration, and calcification in the Enewetak windward reef flat community. Limnol. Oceanogr., 18 106—120. 

Coral reefs occupy a large part of the seas in the tropics of the Pacific and the Caribbean. They are the most diverse and complex marine communities, supporting thousands of fish, algae, and invertebrate species. Studies and actual spills have shown that moderate concentrations of dissolved or dispersed hydrocarbons can kill both the coral and its occupants. Damage depends on the depth, with coral that is near the surface (down to about 6 m) being particularly vulnerable to oil. Many of the animals can repopulate the area rapidly, but since the coral is their primary support, full recovery depends largely on the recovery or recolonization of the coral. Once dead, the coral itself can be very slow to recover. Oil also has several sublethal effects on coral, such as slowed growth or respiration and unnatural coloration. 

Coral reef communities have also demonstrated the ability to take up suspended planktonic organic matter as a source of new carbon (Glynn, 1973 Johannes Gerber, 1974 Ayukai, 1995 Sebens etal., 1997 Fabricius etal., 1998 Ribes etal, 1998 Yahel etal., 1998). Reported rates of particulate carbon uptake are low (<40 mmol Cm-2 day-1) compared to rates of gross primary production and community respiration (Table 2.2), and have been demonstrated to be an unimportant source of carbon for some hard and soft coral communities (Ribes, 1998 submitted). However, the uptake of particulate organic matter may be an important source of food for some specific reef communities (Fabricius etal., 1998). 

There have been no studies measuring both carbon and nutrient fluxes in different morphological zones, nor studies relating net carbon sources and sinks to nutrient fluxes. For many reefs, errors in gross production and respiration are too high (10-15%) to get reliable estimates of net community production (Crossland etal, 1991) while changes in nutrient concentrations are nearly undetectable. Such experimental restrictions have limited our ability to understand the relationship between carbon and nutrient cycles in coral reefs. 

Falter, J.L., Atkinson, M.J. and Langdon, C. (2001) Production-respiration relationships at different time-scales within the Biosphere 2 coral reef biome. Limnology and Oceanography, 46, 1653-1660. 

In a situation of adequate DIG, the quantity and density of zooxanthellae have a direct influence on the stability of the coral reef ecosystem, which is in symbiosis with the coral. Zooxanthellae can produce organic matter and discharge O2 during the photosynthesis process. The majority of organic matter was excreted from coral and O2 was supplied to coral for respiration. Some organic matter was captured by coral as one food source. Some CO2 discharged from coral respiration combined with Ca + in seawater and constructed the coral skeleton. 

The Earth s atmosphere contains about 0.03% by volume of CO2, and the equilibrium in Equation 10.2 means that rain falling through even unpolluted skies will be slightly acidic. CO2 is produced by respiration of plants and animals, but is used by plants in the photosynthesis of carbohydrates. The fossilization of plants in the Carboniferous Period (354-290 million years ago) was responsible for the production of coal. Marine organisms use forms of calcium carbonate (calcite and aragonite) in their exoskeletons. An example of the role of this biomineral in protection is shown in Figure 10.15. Some of these organisms live in coral reefs, but others swim about in the sea, and when they die their shells fall to the sea bed. 

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