. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. Figure 15. Core drilling a large colony of Porites lobata, Secas Islands, Gulf of Chiriqui, Panama. Left to right: Peter W. Glynn and Anibal Velarde. July 23, 1984. signatures in a 365+-year-old Galapagos coral have permitted detection of the Little Ice Age, revealing low sea temperatures during the early 1600s and early 1800s (Dunbar et al., 1994). Further, specific geochemical indicators can also provide information on variations in salinity, rainfall, river outflow (Dunbar et al., 1994; Linsley et al., 1994
. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. Figure 15. Core drilling a large colony of Porites lobata, Secas Islands, Gulf of Chiriqui, Panama. Left to right: Peter W. Glynn and Anibal Velarde. July 23, 1984. signatures in a 365+-year-old Galapagos coral have permitted detection of the Little Ice Age, revealing low sea temperatures during the early 1600s and early 1800s (Dunbar et al., 1994). Further, specific geochemical indicators can also provide information on variations in salinity, rainfall, river outflow (Dunbar et al., 1994; Linsley et al., 1994), upwelling and nutrient availability (Shen and Sanford, 1990; Shen et al., 1992), the timing of volcanic eruptions (Shen et al., 1991), and shifts in the position of the intertropical convergence zone (Linsley et al., 1994). While such paleoclimate studies help advance our understanding of the environmental bounds of reef growth, the extent of these investigations in the eastern Pacific is confined by a generally poor fossil record and high rates of bioerosion following coral death. Another approach that can reveal information on the developmental history of coral communities involves a detailed examination of reef sediments. We have obtained sediments from the Uva reef by air lifting and from push cores (Fig. 16). One must exercise caution that the reef sites selected for study have not been subject to violent storms or burrowing organisms, both factors that could disrupt the sequence of sedimentary strata. The C-14 dating of carbonate sediments from the Uva reef have not shown any time reversals, suggesting minimal mixing of shallow and deep sediment layers. Sediments obtained from m depth ranged from 1,645±300 to 3,830±300 years in age. The Acanthaster skeletal remains throughout the sedimentary strata are equal in abundance to the sea star remains found in surface sediments. This suggests the presence of low-to-moderate Acanthaster abundances (15-30 inds) on the Uva
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