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13. Biogeochemistry of Gulf of Mexico Estuaries: Implications for Management

John W Day Texas A&M University Press ePub

Implications for Management

Thomas S. Bianchi, Jonathan R. Pennock, and Robert R. Twilley

The field of biogeochemistry involves the study of how biological, chemical, and geological processes interact to determine the fate and effects of materials that influence the metabolism of ecosystems. An understanding of the role that biogeochemical and physical processes play in regulating the chemistry and biology of estuaries is fundamental to evaluating complex management issues such as those found in the Gulf of Mexico. As we have described (Bianchi et al. 1999), biogeochemistry links the processes that control the fate of sediments, nutrients, organic matter, and trace metals in estuarine ecosystems. Therefore, this discipline requires an integrated perspective of estuarine dynamics associated with the introduction, transport, and either accumulation or export of materials that largely control primary productivity. The metabolism of in situ primary production, and indirectly the utilization of allochthonous organic matter, is also linked to patterns of secondary productivity and fishery yields in estuaries in the Gulf of Mexico. As humans alter the way regional watersheds and local landscapes of estuaries produce and process natural and synthetic chemicals, principles of biogeochemistry will continue to influence how we manage these unique coastal ecosystems.

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9 The Flexion of Sauropod Pedal Unguals and Testing the Substrate Grip Hypothesis Using the Trackway Fossil Record

Daniel Ma Edited by Peter L Falkingham Indiana University Press ePub

9.1. (A) Mounted diplodocid right pes. Note the deep, laterally compressed unguals and en-echelon arrangement. Morrison Formation, Late Jurassic. Currently on display at New Mexico Museum of Natural History and Science. (B–D) Feet of the specialized scratch-digging tortoise, Gopherus. Note the curvature of the flattened unguals and their similarly en-echelon arrangement. (B) Left manus of Gopherus canyonensis, from Bramble (1982); (C) left manus and (D) pes of Gopherus polyphemus, from Auffenberg (1976). (E) Phylogenetic distribution of sauropod manual morphology (right manus depicted). Manual phalanges exhibit a phylogenetic trend toward reduction and loss, retaining only digit I; derived titanosauriforms take this even further, losing all manual phalanges. Reproduced from Figure 3, Fowler and Hall (2011).

The Flexion of Sauropod Pedal Unguals and Testing the Substrate Grip Hypothesis Using the Trackway Fossil Record


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4 Rocks, Fossils, and Time

Richard Arnold Davis Indiana University Press ePub

Figure 4.1. Cincinnatian stratigraphic nomenclature from 1955 through 1986. From Davis and Cuffey (1998). From Schumacher (1984, figure 2), courtesy of the Ohio Department of Natural Resources Division of Geological Survey. This chart shows stratigraphic subdivisions of the Cincinnatian Series proposed by different researchers for different parts of the Cincinnati Arch region. Subdivisions in the Caster et al. (1955) column were based largely on differences in fossil content. Broader subdivisions such as those of the Brown and Lineback (1966), Hatfield (1968), Gray (1972), Peck (1966), and Lee (1974) columns were based on general characteristics of the rocks (lithology) and bedding. Hay (1981) and Tobin (1986) used both lithologic as well as paleontologic aspects. In the Hatfield column, the vertical lines indicate parts of the section excluded from his study. Units separated by jagged lines indicate lateral changes in rock characteristics (facies).


Fossils in many collections and museum exhibits are often impressive for finely preserved detail and even beauty, because they have undergone painstaking preparation by which every trace of the stony matrix has been removed. However, a fossil so isolated from its embedding matrix also loses much of its significance as a means by which to understand when and how it lived. Only through investigation of the fossil in the rock can we attain a clear understanding of the significance of the abundant Ordovician fossils of the Cincinnati Arch region, or any fossils for that matter. In this chapter we will explore the nature of the rocks in which Cincinnatian fossils are found, the means by which they are subdivided, and the applications of this study to understanding the environments in which they were formed and to determining their geologic age.

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5. Grasslands

Jr John O Whitaker Indiana University Press ePub

This chapter includes all grasslands, including the original tall grass prairie, which comprised more than 2 million acres, mostly in the northern half of Indiana; pasture; haylands; strip-mined land in southwestern Indiana; vegetated dunes; savanna; and agricultural land put into the various reserve programs. “Grassland” often includes more or less forbs or other nongrassy herbaceous plants.

Original Prairie

An understanding of Indiana’s native grassland community, the tall grass prairie, is essential to appreciating the changes to this habitat category in the past 200 years. The French word prairie means “meadow.” But the “Indiana prairie” encountered by early European settlers was unlike any meadows they had ever experienced in the forested regions of Europe. Indiana’s prairie was dominated by grass species, especially big bluestem (Figure 5.1), switchgrass, Indian grass, and in wetter sites slough grass, which all can grow to 10 ft tall or more. A human on horseback could be swallowed up in the vast sea of tall grass. Scattered among the grasses were perennial wildflowers and legumes, collectively called “forbs,” such as blazing star, partridge pea, black-eyed Susan, and various sunflowers (Figure 5.2). Small trees and shrubs, such as hazelnut, occurred at grassland edges, especially along drainages.

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8 - Fears of Civil War

Simon J. Knell Indiana University Press ePub

After a short but violent paroxysm, and about midnight, between the 11th and 12th of August, a luminous cloud enveloped the mountain. The inhabitants of the sides and foot of the volcano betook themselves to flight, “but before they could save themselves, the whole mass began to give way, and the greatest part of it actually fell in and disappeared in the earth.” This was accompanied by sounds like the discharge of heavy cannon.

The Geological Observer (1851)


IN 1967, WILLI ZIEGLER STOOD ON THE SUMMIT OF A utilitarian mountain. Now, as he surveyed the world's Devonian rocks, he fancied that he had within his grasp the means to correlate them all. This mountain had been built through the efforts of generations of stratigraphers who had turned the conodont into an abstract timepiece. Buried somewhere near the mountain's base were Kindle's call to action and Ulrich's erroneous assertions. The greater mass was American and had been shaped by Branson and Mehl and few others. The summit, however – where Ziegler now stood, flag in hand – was largely German. Here, inspired by Beckmann's proof of the conodont's potential in the German Devonian, a whole generation had raced for glory, their heads filled with thoughts of mapping the evolution of animal parts. Only on the upper slopes did Ziegler scramble ahead, driven by ambition, extraordinary resources, and sheer hard work.

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