. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. 35 Unlike the phosphorus budget, the nitrogen budget must be regarded as incomplete. There may be at least two additional sources of nitrogen in the lagoon. An input of NH3 other than that at the lagoon pass is suggested by Fig. 14. The high NH3 values at intermediate salinities along the northeastern margin of the lagoon probably represent either such additional input or NH3 regeneration along that portion of the lagoon. Wind may blow NH3-laden air from bird colonies along the northeastern portion of the isla
. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. 35 Unlike the phosphorus budget, the nitrogen budget must be regarded as incomplete. There may be at least two additional sources of nitrogen in the lagoon. An input of NH3 other than that at the lagoon pass is suggested by Fig. 14. The high NH3 values at intermediate salinities along the northeastern margin of the lagoon probably represent either such additional input or NH3 regeneration along that portion of the lagoon. Wind may blow NH3-laden air from bird colonies along the northeastern portion of the island across the water where it can be rapidly dissolved. This mechanism may have been enhanced during the survey by heavy truck traffic; the ammonia may adsorb onto the resultant dust which falls out along the northeastern portion of the island. Some ground- water input of NH3 from this same island source is also possible, although salinity values do not indicate groundwater influx into the lagoon. Because NH3 is highly labile, the sampling and storage procedures may have also introduced the high values as a sampling artifact. Nevertheless, the coherent distribution pattern argues against the likelihood of such an artifact. Webb et al. (1975) have demonstrated that blue-green algae on shallow reef flats can fix large amounts of atmospheric nitrogen. Such a mechanism could supply a significant fraction of the total nitrogen utilized by the Canton lagoon community. Drouet (in Degener and Degener, 1959) lists several genera of blue-green algae which are found at Canton and which are known to fix nitrogen. Because of these possible additional nitrogen sources, the nitrogen utilization rate calculated here and the ratio of N:P uptake (Table 5) are probably lower limits. Figure 18 is a plot of salinity versus silicon in the lagoon. Unlike nitrogen and phosphorous, silicon shows no functional relationship with salinity. This lack of correlation is actually encouragement for the general
Size: 1400px × 1784px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookauthorsmithsonianinstitutionpress, bookcentury1900
