Assessment of Fish Assemblages Before Dredging of the Shipping Channel Near the Mouth of the Savannah River in Coastal Georgia

Evaluating the effects of anthropogenic activities is dependent upon data collection prior to impact, though funds are rarely allocated to conduct an assessment before a critical need arises. The Savannah Harbor Expansion Project is one such activity that includes dredging of the Savannah River. It may potentially change physical conditions of the estuary thereby altering fish assemblages. The purpose of the present study was to characterize pre-impact fish assemblages along a salinity gradient near the mouth of the river and determine which abiotic factors most influence them. One site within the mouth of the Savannah River and two sites immediately outside the river mouth were sampled monthly for 2 years using both a beam trawl and seine net. Salinity, temperature, dissolved oxygen, and sediment grain size were assessed. All four factors had a significant effect on fish assemblages. A total of 3943 fishes representing ≥55 species formed three statistically distinct fish assemblages and at least three seasonal assemblages. Only 24 species (43.6 %) were collected by both gear types indicating the importance of using multiple gear types to assess fish assemblages. We conclude that the fish assemblages near the mouth of the Savannah River may be altered or may shift given the predicted increase in salinity and/or the possible changes in sediment composition from channel dredging. Understanding the abiotic factors that most influence spatial and seasonal fish distributions prior to dredging will be invaluable in predicting how organisms will be impacted by similar public projects elsewhere.     

Estimates of New and Total Productivity in Central Long Island Sound from In Situ Measurements of Nitrate and Dissolved Oxygen

Biogeochemical cycles in estuaries are regulated by a diverse set of physical and biological variables that operate over a variety of time scales. Using in situ optical sensors, we conducted a high-frequency time-series study of several biogeochemical parameters at a mooring in central Long Island Sound from May to August 2010. During this period, we documented well-defined diel cycles in nitrate concentration that were correlated to dissolved oxygen, wind stress, tidal mixing, and irradiance. By filtering the data to separate the nitrate time series into various signal components, we estimated the amount of variation that could be ascribed to each process. Primary production and surface wind stress explained 59 and 19 %, respectively, of the variation in nitrate concentrations. Less frequent physical forcings, including large-magnitude wind events and spring tides, served to decouple the relationship between oxygen, nitrate, and sunlight on about one quarter of study days. Daytime nitrate minima and dissolved oxygen maxima occurred nearly simultaneously on the majority (>80 %) of days during the study period; both were strongly correlated with the daily peak in irradiance. Nighttime nitrate maxima reflected a pattern in which surface-layer stocks were depleted each afternoon and recharged the following night. Changes in nitrate concentrations were used to generate daily estimates of new primary production (182?±?37 mg?C?m^?2?day^?1) and the f ratio (0.25), i.e., the ratio of production based on nitrate to total production. These estimates, the first of their kind in Long Island Sound, were compared to values of community respiration, primary productivity, and net ecosystem metabolism, which were derived from in situ measurements of oxygen concentration. Daily averages of the three metabolic parameters were 1,660?±?431, 2,080?±?419, and 429?±?203 mg?C?m^?2?day^?1, respectively. While the system remained weakly autotrophic over the duration of the study period, we observed very large day-to-day differences in the f ratio and in the various metabolic parameters.     

Overcoming disciplinary solitude: The archaeology and geology of native copper in Eastern North America

Although native copper has attracted the scholarly attention of both geologists and archaeologists since the middle of the 19th century, it is only recently that native copper studies have benefited from interdisciplinary research. This history of disciplinary solitude can be traced to the professionalization of the two fields in the early 20th century, an era in which crossdisciplinary communication began to wane. The effects of this phenomena resulted in the development of a model of aboriginal native copper procurement by archaeologists that did not take into account the geological literature, which had long identified numerous—rather than a single—source of native copper in North America. In this article, the author discusses how this disciplinary solitude developed and how it resulted in the creation of a dominant model for native copper procurement that constrained our understanding of aboriginal lifeways for generations. The author also considers how increasing collaboration between geologists and archaeologists since the 1970s has led to the reevaluation of an old model of native copper procurement that has been uncritically accepted by most archaeologists for over a century and a half. © 2007 Wiley Periodicals, Inc.     

Walking as Method: Toward Methodological Forthrightness and Comparability in Urban Geographical Research

Qualitative urban geographical research should explicitly acknowledge insights gained from walking (the iterative exploration and observation of cities on foot), which enhances local literacy and enables researchers to compare methods more explicitly. Some urban geographers might use walking as a method, but it is rarely reported in published scholarship. This article argues for the explicit inclusion of walking in methodological reporting for urban research. We suggest that reporting the walking that researchers do adds rigor to research findings and should be distinguished from research where this practice is absent, we report on international experiences using walking in combination with other methods, and we conclude with a proposal for comparable urban geographic walking practices.     

Differentiation of clay resources on a limestone plain: The analysis of clay utilization during the Maya Formative at K'axob Belize

Differentiating clay resources in a uniform limestone plain, such as occurs in northern Belize, offers special challenges for the archaeologist. Combining data from soil mapping with petrographic and neutron activation analysis provides a mechanism for distinguishing possible resource areas. This study employed each of these differing avenues of analysis to determine possible clay resource areas used during the Maya Formative in northern Belize Central America. The results indicate that clay usage changed significantly from the Middle Formative period to the end of Late Formative period. These changes suggest a move to increased localized production and resource exploitation by the end of the period. © 2000 John Wiley & Sons, Inc.     

Preliminary study on the preservation of giant clam (Tridacnidae) shells from the Balobok Rockshelter archaeological site,south Philippines

Tridacnidae shells, a valuable archive of past environments, are common in the Balobok Rockshelter archaeological site on Sanga‐Sanga Island in the south Philippines. This site was occupied during the mid‐Holocene (ca. 5000–8800 ¹⁴C yr B.P.), a period of Neolithic cultural expansion in the Philippines. This paper focuses on the preservation of two shell specimens, Hippopus hippopus and Tridacna maxima, unearthed from two mid‐Holocene layers within the rockshelter. The shells' mineralogy and microstructure (prismatic and crossed‐lamellar) were studied using micro‐Fourier transform infrared spectroscopy and scanning electron microscopy to determine if the samples were suitable as paleoenvironmental records. Both shells are still aragonitic but aragonite crystals of both microstructure types are partly dissolved. This dissolution, characteristic of meteoric water alteration, precludes their utility in paleoenvironmental geochemical studies. Nevertheless, these shells are abundant in archaeological sites in the region and may be better preserved in other depositional contexts; more studies on Philippine Tridacnidae shell diagenesis are needed. © 2011 Wiley Periodicals, Inc.     

Cave bears and paleolithic artifacts in Yarimburgaz Cave,Turkey: Dissecting a palimpsest

This article addresses the taphonomic issues surrounding artifact-bear associations in Yarimburgaz Cave, northwestern Turkey. Our purpose is to evaluate the circumstances of bone assemblage formation in the Middle Pleistocene deposits of the cave, identifying the agencies responsible for the accumulations and the causes of bone damage before and following deposition. Pleistocene species representation, bone damage, body part representation, and mortality data indicate that cave bear remains in Yarimburgaz are unrelated to hominid use of the same site. None of the observations on the cave bear remains contradicts the expectations developed from modern wildlife accounts of modern bear behavior; these accumulations resulted from mortality normally associated with hibernation over many generations of den use. Nonursid carnivores also played roles in bone collection and/or modification. We conclude that at least three distinct biological processes contributed to the formation of the Middle Pleistocene faunas: hibernating bears, bone-collecting carnivores such as wolves, and hominids in descending order of importance. The Yarimburgaz faunas represent palimpsests or overlays of many short-term depositional events, the close spatial associations of which are explained by slow or uneven sedimentation rates inside the cave. Although occupations by hominids appear to have been ephemeral in nature, hominids ultimately discarded nearly 1700 stone artifacts in Yarimburgaz Cave. The hominids did not discard many ungulate bones in the same circumstances. These observations suggest that hominid foraging efforts focused on resources other than large game while at the cave. © 1996 John Wiley & Sons, Inc.