Towards an unbiased estimate of fluctuations in reef abundance and volume during the Phanerozoic

Abstract

Abstract. The globally preserved number and volume of ancient biogenic reefs is strongly biased by two factors: geological history and research intensity. These biases are sufficiently strong to cast doubts on the biological meaning of the recorded raw pattern. Without adjustment, it is hard to reliably identify factors potentially controlling the waxing and waning of this important ecosystem through time. Although it is currently impossible to completely compensate for the biases, I demonstrate here, based on a comprehensive database of ancient reefs, that spatiotemporal heterogeneities of the biases can largely be evened out by: (1) omitting oceanic reef sites and reef sites only known from subsurface exploration; (2) standardizing for economic factors known to affect research intensity; and (3) adjusting for sedimentary cycling processes. The resulting curves of fossil reef abundance and volume appear quite different from the original ones but the patterns of waxing and waning of the time series are not significantly altered and the overall volatility is not reduced. This suggests that both the raw curves and the adjusted curves correctly depict the basic timing of major reef blooms and declines. Nevertheless, the general pattern of the new curves (maximum proliferation in the middle Paleozoic, decline thereafter) is more in line with patterns of global cratonic carbonate sedimentation than the original curves. The adjusted curves should thus be preferred over the original ones for future tests of potential extrinsic controls of Phanerozoic reef development.

On the potential for ocean acidification to be a general cause of ancient reef crises

“…which is in accordance with previous studies on the geologic record of reefs (Kiessling et al, 2000;Kiessling, 2006Kiessling, , 2008. Therefore, only the most extreme depressions are identified as significant reef crises.…”

Sampling-standardized expansion and collapse of reef building in the Phanerozoic

“…The time series of reef abundance (Fig. 1) shows the same rugged pattern as in previous plots resolved to different time scales (Kiessling 2002(Kiessling , 2006. In spite of the volatile curves, there are significant lag one autocorrelations in the time series of metazoan reefs (r A ¼ 0.30, p ¼ 0.03) and tropical coral-sponge reefs (r A ¼ 0.37, p ¼ 0.008).…”

“…Volatility is assessed by the standard deviation of first differences. Although standard measures of volatility use proportional rather than absolute changes (Kiessling 2006), this approach is not feasible here, because some reef time series include null values. However, the differences in scale need to be taken into account by calculating the standard deviation of first differences of normalized values (proportional differences from the mean).…”

“…Two major problems hinder the detection of biologically meaningful patterns in reef production on geological time scales: Genuine variations in the preservation of sedimentary rocks and (economically driven) heterogeneities in exploration intensity (Kiessling 2005a(Kiessling , 2006. Kiessling (2006) has tried to compensate for much of this bias and uncovered the probable pattern of changes in absolute reef abundance and volume through the Phanerozoic. His pattern of a maximum proliferation of reefs in the Silurian and Devonian and a steep decline thereafter, interrupted by short-term peaks, provides insights into absolute changes in reef production, but does not elucidate variations relative to changes in the fossil record.…”

Post-tectonic limitations on Early Devonian (Emsian) reef development in the Gobi-Altai region, Mongolia

“…During the Early Devonian, shallow‐marine carbonate depositional systems across the world, including the Siberian, Timan‐Pechora, Alberta, central Europe, Morocco and South China platforms, supported reef development (James & Bourque 1992; Kiessling et al. 1999; Copper & Scotese 2003; Kiessling 2006). Generally, the reefs were constructed by a diversity of stromatoporoid sponges, tabulates and colonial rugose corals characterized by domal growth forms.…”