The fossil record of biodiversity: nutrients, productivity, habitat area and differential preservation

Abstract

Martin, R.E. 2003 09 12: The fossil record of biodiversity: nutrients, productivity, habitat area and differential preservation. Lethaia, Vol. 36, pp. 179±194. Oslo. ISSN 0024-1164. It is hypothesized that the Phanerozoic record of fossil diversity is a function of a secular increase in nutrient availability and productivity (food, energy), and cyclic changes in sea level and habitat area due to supercontinent assembly and rifting. Both variables may have affected biodiversity through the combined variable of {productivity  area}. {Productivity  area} remained relatively constant after the Cambro-Ordovician until the end of the Permian, as did the traditional curve for biodiversity. During assembly of Pangea, decreasing sea level and habitat area were counteracted by increasing nutrient inputs due to uplift and the spread of vascular plants and enhanced continental weathering. As Pangea underwent its ®nal assembly, interior drainage increased, so that by the end of the Permian both habitat area and nutrient runoff decreased. Following the end-Permian extinctions, the traditional curve of diversity began to increase, habitat area, nutrient levels and productivity all increased. Despite the confounding factors of differential preservation and sampling bias toward the present, the fossil record re¯ects a real response by the marine biosphere to tectonism, sea level, paleoceanographic regime and climate, and the spread of terrestrial¯oras, and their in¯uence on habitat area, nutrient inputs, and productivity through time.

Diversification and faunal shift of Siluro‐Devonian vertebrates of China

“…The origination and rapid diversification of major sarcopterygian lineages in South China may be related to the geographic isolation and tropical setting of these early fishes. The fossil record implies that there are greater opportunities for evolutionary innovation in the tropics (Martin 2003).…”

“…Over the past quarter century, biotic interactions, mass extinctions and physical perturbations were thought to play the pivotal role in governing long-term biotic transitions during the Phanerozoic (Gould and Calloway 1980;Sepkoski 1996;Miller 1998Miller , 2002Martin 2003;Peters 2005).…”

“…On the one hand, the transgression process led to the gradual increase of shallow marine shelf environments, particularly nearshore environments, which supplied the more favourable ecological niche for the evolution of early vertebrates. On the other hand, the continual transgression also resulted in the increase of erosion rate and suspended/dissolved loads (Martin 2003), which supplied sufficient trophic resources (e.g. food) for benthic taxa of early vertebrates.…”

Temporal patterns of barren intervals in the Phanerozoic

“…A much more straightforward explanation of the declining numbers of barren marine rock units is that marine shelf habitats have simply become more extensively populated by skeletonized animals over time, a trend prob- ably driven by increasing levels of primary productivity and nutrient levels (Martin 2003). Increasingly populous seas, combined with the declining proportion of tectonized terranes and metasediments through the Phanerozoic, in which the fossil record is obliterated, could easily create the observed pattern.…”

Nitrogen and Productivity in the Late Devonian Appalachian Basin

“…Many authors have proposed a connection between terrestrially-derived nutrients, the deposition of organic-rich facies and diversity loss among Late Devonian marine life (Bambach 1993;Caplan, et al 1996;Martin 1996;Algeo, et al 1998;Martin 1998;Bambach 1999;Gong, et al 2002;Chen, et al 2003;Martin 2003;Gong, et al 2005;Saltzman 2005) without, however, specifying how the changing biogeochemical cycling of specific elements created the evidence found in the geological record. The fundamental hypothesis that this study seeks to address is that the link between the biogeochemical cycle of nitrogen on the land and in the sea is a key to explicating the deposition of organic-rich sediments and consequent changes in the oceans, atmosphere, and biosphere during the Late Devonian.…”