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St. Catherines Island is one of several barrier islands lining the coast of Georgia, USA. This island is among the least recently anthropogenically impacted of the Georgia Sea Islands, but had not previously been examined in detail for coastal invertebrate macrofauna. From 1992 through late 1998 a coastal survey was conducted that examined the diverse marine invertebrate fauna of St. Catherines Island. Salt marshes, sand flats, mid- to low-energy sand beaches, beach wood debris, tidal creeks, shallow benthos, and artificial hard substrata (including docks) were qualitatively sampled for macroinvertebrates. Over 340 species were identified. Crustaceans composed close to 40% (14% amphipods; 15% decapods), polychaetes 17.5%, and molluscs about 25% of all species recovered. These results are compared to the few other relevant studies from the United States mid-Atlantic Coast.

Aqueous-phased xenobiotic contaminant exposure can biochemically modify newly generated periostracum of the Asian freshwater bivalve,Corbicula fluminea. Laser-induced desorption of partially polymerized periostracum produces spectra distinguishable from mass spectral images generated from uncontaminated periostracum. Organic xenobiotic contamination putatively impedes full polymerization of the periostracin protein. The detection of the effects of pollution on periostracum by the laser microprobe mass analyzer constitutes a novel bioprobe for the definitive but qualified detection of xenobiotic contamination.

A freshwater bioprobe, combining the Asiatic Clam, Corbicula fluminea (Müller) and the laser microprobe mass spectrometer (LAMMA), can determine anthropogenic chemical contamination of freshwater systems. Laser generated mass spectra from the periostracal layers of clams contaminated with either a salt, potassium bromide, or an aromatic compound, phenol, produce distinctive mass spectral signatures that are different from uncontaminated clams. Uncontaminated clams have characteristic signatures with distinctive spectral peaks less than m/z 41; while exposed clams have many strong peaks well above this m/z. This freshwater bioprobe, using LAMMA to analyze the surface of clams, can be used as a screening tool for monitoring the water-treatment systems, for determining the source of contaminated baseflow and return flow discharge to streams, and for monitoring the water chemistry of a body of water. This system exploits the facility of using the shell instead of soft tissue with the LAMMA and has potential to detect anthropogenically-derived chemical stress.

Lateral fluctuations of shoreline positions along shallow basinal margins often result in spatially and temporally overprinted (palimpsested) firmground or hardground surfaces (Frey and Basan, 1981). Recent palimpsested surfaces can teach us a great deal about the fossil record, particularly when we view them taphonomically. For the last few years we have been studying such surfaces along the seaward coast of St. Catherines Island, Georgia. In this paper we will first briefly discuss the modern salt marsh at St. Catherines Island, and its invertebrate inhabitants. This will form a basis for recognition and description of relict marsh surfaces. We will next describe the relict salt marsh surface that is currently being exhumed by coastal erosion and palimpsested by other invertebrate communities. Such palimpsested events also represent heterochronous community replacement–the disjunct temporal and (usually) spatial overprinting of an older community (or biogenic surface) by one (or more) younger communities. This interprets “replacement” as a passive, generally species non-interactive, phenomenon (contra Miller, 1986). Lastly, we will make some rather broad comparisons between the St. Catherines Island setting and what we interpret as analogous situations recorded in the Carboniferous strata of the Appalachian Basin.

Stratigraphy provides a basic temporal and spatial framework for all studies of earth history. The foundations of stratigraphy were built in the 17th and 18th centuries through the efforts of Steno and Smith. Formalization of the principles of organic evolution followed closely in the mid-19th century with the publication of the Origin of Species. Although paleoecological observations span centuries, the establishment of paleoecology as a scientific discipline is a 20th century phenomenon. Initially, paleontology (paleobiology) was an integral part of stratigraphy and housed the subdisciplinary studies of evolution and paleoecology. Retention of a stratigraphic framework soon became difficult, perhaps due to the potential for circular reasoning in the evolutionary study of fossils. If the rock record was subdivided on the basis of fossils, how could the evolutionary relationships of these organisms be evaluated when they, or related forms, had been used to construct the temporal framework?

Publisher Summary This chapter reviews the history of study and the current status of Mid-Holocene climatic and cultural change along the Peruvian coast, with a focus on major transitions at ca. 5800 and 3000 cal yr BP that correlate temporally with changes in El Nino Southern Oscillation (ENSO) frequency. It begins with presenting the Peruvian archaeological record of Holocene El Nino frequency variation, considering several hypotheses to explain the data. Based on the archaeological record, it is concluded that for some time prior to 5800 years ago, the coast of Peru, north of 10°S latitude, was characterized by permanent warm water. From these data, it is hypothesized that El Nino did not operate for some period before 5800 cal yr BP; after that time, conditions as essentially the same as today were seen. Present-day climatic variability on interannual time scales in the tropics is dominated by ENSO, which involves both the atmosphere and the ocean in the tropical Pacific (e.g., Maasch, in press). Through teleconnections, extratropical climatic variability on these time scales is also impacted by ENSO. Continuous natural Holocene paleoclimate archives from northern Peru, Ecuador, and the eastern tropical Pacific Ocean are difficult to find, privileging anthropogenic deposits from archaeological sites. Although precisely dating these records is difficult, climatic change determined from them is consistent. The regional paleoclimate records are presented.

For the tropical west coast of South America, where El Nino/Southern Oscillation (ENSO) is most pronounced, archaeological and associated paleontological deposits in northern Peru revealed a major climate change at about 5000 years before the present (yr B.P.). The data implied the presence of stable, warm tropical water as far south as 10°S during the early mid-Holocene (about 8000 to 5000 yr B.P.). These data suggest that ENSO did not occur for some millennia preceding 5000 yr B.P., when global and regional climate was warmer than today.

Analysis of mollusks from archaeological sites on the north and central coasts of Peru indicates that between ca. 5800 and 3200–2800 cal yr B.P., El Nino events were less frequent than today, with modern, rapid recurrence intervals achieved only after that time. For several millennia prior to 5.8 ka, El Nino events had been absent or very different from today. The phenomena called El Nino have had severe consequences for the modern and colonial (historically recorded) inhabitants of Peru, and El Nino events also influenced prehistoric cultural development: the onset of El Nino events at 5.8 ka correlates temporally with the beginning of monumental temple construction on the Peruvian coast, and the increase in El Nino frequency after 3.2–2.8 ka correlates with the abandonment of monumental temples in the same region.

Burrowing and plowing gastropods may have existed prior to the Mesozoic, contrary to the conservative tendency of categorizing Paleozoic archaeogastropods as herbivorous hardground dwellers. We propose that Euphemites and other bellerophontiform molluscs such as Praematuratroph and Beyrichidiscus make functional and paleoecological sense only if reconstructed with an internal shell adapted to an infaunal mode of life. Attributes diagnostic of a probable infaunal mode of life in fossil bellerophontiform molluscs include: (1) lack of apertural flare; (2) restricted aperture; (3) low rate of whorl expansion; (4) semi-radial aperture; (5) extensive secondary shell deposits; (6) absence of extensive collabral ornament; (7) dorsolateral or umbilical furrows; (8) color patterns indicative of mantle extension and retraction capabilities; (9) absence of shell breakage and repair; and (10) associated lithologies indicative of penetrable substrates such as mudstones. Niche diversity in the bellerophontacean molluscs was probably much greater than previously suspected. This is entirely consistent with their long geologic range. Most bellerophontaceans, particularly the Late Paleozoic forms, were probably either ‘nestling’ or semi-infaunal with the apertural margins enwrapped by mantle or mantle and foot. As such they may have been particularly susceptible to predation during the postulated Mesozoic increase in number of infaunal predators- a factor which may have been contributory to the bellerophontacean demise.

The science of paleoecology suffers from a lack of conceptual frameworks. Paleoecologists have been overconcerned with the inadequacies of the fossil record: as a result, community palmecology has historically developed very slowly. At the community ecosystem level, the need for a theoretical framework is so great that paleoecology must ‘borrow’ the hypotheses of modem ecology. Consideration of the stability-time hypothesis of Sanders in conjunction with the physical setting of transgression and regression has permitted the structuring of three community types and the interpretation of their behavior under variations in the physical environment. These community types (opportunistic. stable mature, relict mature) are recognizable in the fossil record and examples are given from the Upper Pennsylvanian of the Appalachian Basin.

The 1982–1983 El Nino event afforded the opportunity to develop criteria for the recognition of ancient El Ninos using mollusks from archaeological sites along coastal South America. A combination of growth increment and stable isotope analyses indicated that elevated sea surface temperatures during large scale El Ninos leave a record decodable from the growth patterns of selected bivalve shells. The intertidal venerid Chione subrugosa displayed a pronounced break in the valve margin profile following the 1982-1983 event but provided an inconsistent stable isotope pattern. The subtidal carditid Trachycardium procerum, on the other hand, preserved a discernible and diagnostic growth interruption as well as an expected trend in stable isotope indicators of salinity and temperature change. We conclude that some of the major culturally disruptive El Nino events can be recognized in the geoarchaeological record by these techniques, especially if ancillary information, such as faunal distribution patterns, are also considered. Perhaps the most serious constraint upon application of this approach involves microstratigraphic resolution of shell midden deposits. Stratigraphic sampling of midden material should be accompanied, if possible, by sampling of proximal natural strata. The chances of discovery of major El Nino perturbations in the geoarchaeological record of shell middens is enhanced by the catastrophic nature of such events and by the indication that major El Ninos have a high probability of being closely spaced in time.

Recent paleoecological studies have emphasized the recognition of successional stages of level-bottom communities, but have neglected to point out techniques for distinguishing succession within a fossil community from the temporal and spatial replacement of one fossil community by another. The physical integrity of a marine level-bottom community is discernible, in most instances, through careful temporal and spatial study, and one community can be distinguished from another by judicious application of the ‘end-member’ concept. Community boundaries are only as distinct as the associated environmental stress gradient. Of first-order significance in understanding fossil community succession and replacement is appreciation of the basic asymmetry of the community dynamics involved in transgression-regression events. Of second-order importance is appreciation of the nature of the onshore-offshore environmental stress gradient, which, in turn, is controlled by the physical setting of transgression-regression (e.g. progradation versus eustatic control; high topographic relief versus low topographic relief, etc.). The application of the preceding concepts is shown by detailed study of community succession and replacement in the Cambridge Limestone (Upper Pennsylvanian), Guernsey County, Ohio.

The oceanographic phenomenon known as El Nino is the subject of intensive recent study. Any hypotheses regarding physical causes and predictability of El Nino should consider its geological history. New geoarchaeological evidence suggests that the El Nino phenomenon did not exist along the northern and central coasts of Peru before about 5000 years B.P. Molluscan faunas from archaeological sites at Pampa las Salinas and Salinas de Chao permit temporal bracketing of a major structural change in the East Pacific water mass. The boundary between the warm Panamic Province and the cold Peruvian Province, which today occurs at about 5 degrees south latitude, was some 500 km further south from at least 11,000 years B.P. to about 5000 years B.P. This conclusion is corroborated by many other lines of evidence including phosphorite distribution, timing of glacial retreat, sea level change, radiolarian, diatom and fish scale distributions, and beach ridge patterns. The present day arid coastal climate of north central Peru is probably a post-5000 year B.P. development. Hunter–gatherer populations of the area would most likely have exploited more land-based seasonal resources from grasslands and forests before 5000 years B.P., and relied less upon the diminished productivity of warm water maritime resources.

Carboniferous strata can be described, interpreted, and correlated using six scales of allocyclic transgressive-regressive (T-R) units. These T-R units are inferred to be the net result of deposition during cycles of sea-level change. All Pennsylvanian and Lower Permian strata constitute one second-order T-R unit, or synthem. The Pennsylvanian System contains third-, fourth-, fifth-, and sixth-order T-R units that can be correlated across both marine and nonmarine facies in the Appalachian Basin. This permits differentiation of allocyclic T-R units from autocyclic T-R units or fluvial autocyclic units. The hierarchical approach is also useful for predicting the location of marine horizons, coals, claystones, and various types of stratigraphic breaks. A hierarchical scheme of allocyclic T-R units could be combined with biostratigraphic, radiometric, and magnetostratigraphic data to form a practical chronostratigraphic framework for the Carboniferous.

A number of recent studies cast doubt on the reliability of using size-frequency distributions of fossil species for inferring ecological age-survivorship curves, fossil community structure, and paleoenvironments. Survivorship curves for fossil taxa are really post-larval size-survivorship curves. Data are lacking for the normally enormous mortalities that occur during larval stages. Such curves represent the effects of differential taphonomy upon various size classes. Before dismissing the paleoecological application of ecological survivorship curving, the patterns of sizefrequency distributions of very large and spatially disparate populations of extant species should be explored. Emphasis to date has been upon temporal, not spatial, averaging in the generation of fossil assemblages. We provide size-survivorship and reconstructed age-survivorship curves on over 2.5 million live individuals of the infaunal bivalve Mya arenaria from 1, 093 collecting sites at 15 locations within four estuaries from eastern Massachusetts. A significant difference was found among the cohort structures of post-larval M. arenaria from the four estuaries, even though environmental settings were similar. A summary cohort curve was constructed that may be analogous to very extensive (but perhaps unlikely) spatial averaging in the generation of a fossil assemblage. The size-survivorship curves constructed for the four estuaries and for the 15 locations exhibit considerable variation from the summary curve. This supports the contention that size-survivorship data gleaned from ecological contexts should only be applied to the paleoecological record with extreme caution.