Exploring Oyster (Crassostrea virginica) Habitat Collection via Oxygen Isotope Geochemistry and its Implications for Ritual and Mound Construction at Crystal River and Roberts Island,Florida

Research at Crystal River and Roberts Island Shell Mound Complex, on the western coast of Florida, USA, offers a quantitative assessment of the temporality of shell deposit construction, Native subsistence practices, and mobility patterns through stable oxygen isotope data from eastern oyster (C. virginica). The δ¹⁸O_water values of oysters vary synchronously with salinity, assuming relatively constant δ¹⁸O_water/salinity gradients since the time of occupation, allowing for an examination of shifts in oyster habitat exploitation over time. Our previous (Thompson et al. 2015) study indicated that midden accumulation occurred throughout the year, while oysters from mound deposits were collected in colder months. New data indicate that in addition to differential season of collection, habitat exploitation also varied. During early occupation at the site, oysters were collected primarily from lower saline habitats, while in later phases oysters were obtained from higher salinity waters; we relate this to a lower sea level and concomitant settlement shift seaward. Additionally, oyster from later mound contexts was collected from higher saline habitats relative to those in midden contexts; Native people may have targeted specific bioherms at certain times for the year for feasting-related mound construction.     

OYSTER DEMOGRAPHICS AND THE CREATION OF COASTAL MONUMENTS AT ROBERTS ISLAND MOUND COMPLEX,FLORIDA

Abstract

Anthropogenic coastal landscapes often incorporate shell, a durable remnant of subsistence activity. Collection, consumption, and even feasting can thus contribute to histories of site formation and mound construction. This research assesses how oyster consumption related to the creation of Mound A, a shell mound at the Roberts Island Shell Mound Complex in Citrus County, Florida, is differentiated from the instances of oyster consumption that resulted in the midden constituting the rest of the island. I compare the size of shell remains from mound and off-mound midden contexts to assess variation in the sizes represented across the samples, stratigraphic variation within each context, and evidence for directional change indicative of over-exploitation. I identify a relationship of dependence between shell size and stratigraphic depth in off-mound samples that does not appear in mound samples, suggesting a relatively short period of time for the accumulation of mound deposit oyster shells. The findings of this study point to mound construction at Roberts Island Shell Mound Complex as a distinct and deliberate activity, with the construction event likely sharing importance with the community aggregation and consumption that facilitated it.     

Morphometric analysis of limpets from an Iron-Age shell midden found in northwest Portugal

The present work reports an analysis of a shell midden found in Terroso hillfort, an important Iron-Age oppidum located in northwest Portugal. The midden was dated from the latest phase of occupation of the hillfort, between the Ist century BC and the Ist century AD (Roman period), and contained 684 well-preserved Patella shells. The identification of archaeological shells was carried out comparing them with modern specimens collected in two shores in the neighborhood of the hillfort. The identification of modern shells was based on radula pluricuspid teeth and shell morphology. Relative abundance of Patella species in the Terroso midden was different from modern populations. Archaeological shells were dominated by Patella vulgata, but Patella intermedia was the most abundant species in modern populations. Dimensions of archaeological shells were very different from modern populations. Shell length range and variability in archaeological shells were lower than in the modern populations. Log height vs. length plots for archaeological shells were different from modern populations. Patella shells from Terroso midden was significantly taller then modern specimens. These differences between archaeological shells and modern populations could be due to environmental changes, namely an increase in wave action and intensity. These harsher costal conditions could have resulted from an alteration in the morphology of the coast, caused by a rise in the mean sea level from 2000 years BP to the present. Alternatively or additionally, the observed differences can be related to gathering strategies. Archaeological shells could have been selected by size, and collected preferentially at high shore and in sheltered sites.     

Archaeological Site or Natural Marine Community? Excavation of a Submerged Shell Mound in Ninigret Pond,Rhode Island

ABSTRACT

Submerged shell midden sites and natural shell deposits can have similar characteristics and can be difficult to distinguish archaeologically. We excavated two test units from a large (at least 35 m×70 m) submerged shell mound in Fort Neck Cove in southern Rhode Island to assess whether it was natural or cultural in origin. This mound had been recognized as a potential archaeological feature as early as the 1970s. Excavation, radiocarbon dating, and subsequent laboratory analysis of excavated materials suggest that the mound was a natural oyster reef rather than a submerged archaeological site. No artifacts were found; there was no clear evidence for human modification of any shells; small species that would not have been targeted as food were present; and δ¹³C values of oyster shells from the mound were consistent with freshwater input into their growth environment, suggesting that they grew in an estuarine environment that did not exist prior to the inundation of the ponds. The stratigraphically oldest radiocarbon date we could obtain (430–190 cal BP, 2σ range), from 70 cm below the pond floor, placed deposition of shells at least 3,000 years after the inundation of the pond. The excavation methods that we used and the process of testing, irrespective of whether the feature is cultural, are valuable contributions to the methodological literature on submerged site archaeology and help provide insight for other researchers working to discern natural from cultural shell midden sites.     

Commercializing Nature: Mangrove Conservation and Female Oyster Collectors in The Gambia

Abstract: Taking a political ecology approach, this paper offers a critical evaluation of conservation efforts undertaken in Gambia's Tanbi Wetland National Park (TWNP), a “wetland of international importance” as designated by the Ramsar Convention. Focusing on the oyster commercialization component of the World Wildlife Fund's Gambia–Senegal Sustainable Fisheries Program (GSFP) in the TWNP mangrove forests, we identify oystering practices that promote mangrove conservation and others that conflict with sustainable management. The project, which aims to commercialize oyster culture through local women, is entirely production oriented, ignoring the ways in which oysters are prepared for market. As a result, degradation of the very mangrove forests the GSFP aims to conserve may be accelerated. The project selectively engages with local environmental knowledge and fails to consider the implications of expanding the value chains for oysters and their shells. Unless the World Wildlife Fund addresses these issues, its conservation objectives and potential socioeconomic benefits may be compromised.     

The Changing Exploitation of Oysters (Ostrea edulis L. 1758) in Late Medieval and Early Modern England: A Case Study from Dudley Castle,West Midlands

ABSTRACT

Analysis of over 4000 complete left oyster valves from late medieval and post-medieval Dudley Castle reveals the changing role of this perishable luxury over a 700-year period. Throughout the occupation, it seems that oysters were used as ingredients rather than served raw in the shell. A greater reliance on oyster consumption is apparent in the later fourteenth century, perhaps reflecting a more diverse diet amongst the aristocracy in the wake of the Black Death. An increased preference for mussels and whelks is also attested in the Tudor and early modern periods, reflecting changing perceptions of these foods.

Overall, it is likely that natural beds were exploited throughout the time that oysters were being brought to Dudley Castle; however, the evidence demonstrates a shift from limited exploitation of natural inter-tidal sources in the eleventh century towards the dredging of sub-littoral beds in later periods, with some possible translocation of oyster stock. Changes in the shape, size and appearance of the oyster shells suggest the source locales from which the oysters derived changed through time. A notable shift occurred in the fourteenth century, which could reflect changes in supply brought about by altered tenancy at Dudley Castle and/or disruptions to trade brought about by the Black Death. Future biochemical analyses are recommended to provide greater clarity on the origin of those sources.     

The role of molluscs in coastal economies: The results of midden analysis in Australia

Complementary techniques of midden analysis have been applied to large oyster mounds on the Richmond River, New South Wales, in order to quantify the dietary contribution of the molluscs. The results are compared with modern data on oyster yields and ethnohistorical data on diet and population size and suggest that, if oysters were the primary food supply while the shell mounds were in use, the sites would have been occupied, on the average, for as little as one week/year. The implications of this for the interpretation of molluscs as a food resource and for the use of shell middens as sources of information about economy, settlement pattern and material culture are discussed.     

Horticulturists and oxygen ecozones in the tropical and subtropical forests of Southeast South America

We analyse the isotopic values (δ¹³C, δ¹⁵N) of the diet of pre-Columbian horticulturalist populations from tropical and subtropical areas of southeastern South America, belonging to the Guarani and Taquara archaeological units. The data indicate different trends in each one (T?=?4.21; P?=?0.0004), showing a mixed diet with maize consumption in the Guarani samples (δ¹³C_co?=??15.5?±?1.8‰; δ¹³C_ap ?10.4?±?0.8‰) and a depleted one in the Taquara ones (δ¹³C_co ?18.2?±?1.7‰; δ¹³C_ap ?11.9?±?0.9‰), with a significant internal dispersion in both populations. The first population has higher nitrogen values (δ¹⁵N 11.1?±?0.6‰) compared to the Taquara samples (δ¹⁵N 9.3?±?1‰), suggesting a more carnivorous diet. The recognition of these pre-Columbian mixed diets involves the identification of maize cultivation on the Atlantic side of the southernmost area of South America (Parana Delta, 34° SL). Through the analysis of δ¹⁸O we have identified two isotopic ecozones, the first along the Paraná River Valley, with an average value of δ¹⁸O ?3.7?±?0.5‰ (CV?=?13.5%; CI?=??3.83 / ?3.16), and the second one, located in the Planalto of southern Brazil (Araucaria Forest), with a mean value of δ¹⁸O ?1.5?±?0.3‰ (CV?=?16.5%; CI?=??1.69 / ?1.29). The isotopic data (δ¹³C, δ¹⁵N and δ¹⁸O) suggest human movements between these two ecozones.     

Mid‐Holocene Development of Mangrove Communities Featuring Rhizophoraceae and Geomorphic Change in the Richmond River Estuary,New South Wales,Australia

This paper describes the hitherto unreported occurrence of mid‐Holocene mangrove deposits in the Richmond River estuary, southeastern Australia, thereby providing evidence for changes in the distribution and composition of mangrove communities within a subtropical estuarine system during the Holocene. Stratigraphic, radiocarbon and palynological evidence indicates that widespread development of mangrove communities took place in the upstream reaches of the Richmond River estuary during the period 7000 to 6000 years BP. These communities maintained their habitat through substrate aggradation under the conditions of a moderate sea‐level rise, in contrast to other estuaries within the region, which generally experienced the submergence of intertidal substrates. Mangrove species belonging to the family Rhizophoraceae, most likely Bruguiera gymnorrhiza and Rhizophora stylosa, dominated these communities, in strong contrast to contemporary communities, which are dominated by Avicennia marina. Moreover, these mid‐Holocene communities were located a considerable distance upstream of the contemporary occurrences of Rhizophoraceae species within the estuary. The changes in the spatial distribution and composition of mangrove communities parallel the large‐scale evolution of the estuary driven by sea‐level variation. Shallow, buried Pleistocene terraces probably contributed to the regionally unique aggradational response of the mangrove communities and their substrates to a sea‐level rise during mid‐Holocene times.     

Refit and Oxygen Isotope Analysis of Freshwater Mussel Shells from the Tillar Farms Site (3DR30), Southeast Arkansas

ABSTRACT

We investigate the link between the consumption of foodstuffs, excavation of a large pit, and disposal of waste at the Tillar Farms site (3DR30), southeast Arkansas, using refit and oxygen isotope analyses of well-preserved freshwater mussel shells from Feature 1. Only 0.13% of 7,408 valves analyzed were unidentifiable to species.The refit analysis produced 460 refits across 23 species and strongly indicates that the shell midden represents a single episode of shellfish gathering, consumption, and discard. Oxygen isotope analysis of five randomly selected shells are used as a test of the refit results. δ¹⁸O values from the five archaeological shells are compared to modern control samples of live-collected specimens from Bayou Bartholomew in winter of 2011. Refit analysis suggests the accumulation of mussel shells occurred quickly, likely as a result of one collection, consumption, and discard event. δ¹⁸O values suggest this activity took place during a single winter season.     

Terrestrial hermit crabs (Anomura: Coenobitidae) as taphonomic agents in circum-tropical coastal sites

Hermit crabs are ever alert for more suitable shells to inhabit, but what this may mean for coastal shell middens has rarely been considered. Here, the impact of the most landward-based of hermit crab families, the tropical Coenobitidae, upon archaeological shell-bearing deposits is assessed using a case study: the Neolithic Ugaga site from Fiji. At Ugaga, hermit crabs were found to have removed the majority of shells from the midden and had deposited their old, worn shells in return. The behavioural ecology of genus Coenobita suggests a mutualistic interaction whereby humans make available shell and food resources to hermit crabs, which in turn provide a site cleaning service by consuming human and domestic waste. Diagnostic indicators of terrestrial hermit crab wear patterns on gastropod shells are outlined and the conditions under which extensive ‘hermitting’ of shell midden deposits may occur are investigated. The ability to recognise hermit crab modification of shells is considered not only important for archaeomalacologists analysing tropical shell deposits, but also for field archaeologists wishing to select suitable shell samples for radiocarbon dating.     

Bahamian hutia (Geocapromys ingrahami) in the Lucayan Realm: Pre-Columbian Exploitation and Translocation

ABSTRACT

Bahamian hutia (Geocapromys ingrahami) are endemic to The Bahamas. The skeletal remains of this species have been recovered from multiple Lucayan-associated archaeological sites in the region, suggesting that it was an important source of human food. This study explores the role of pre-Columbian indigenous peoples in the geographic distribution of Bahamian hutias, and the possibility of intentional management of the animal. We provide an overview of archaeological occurrences of Bahamian hutia and present new skeletal morphometric data comparing modern museum-curated Bahamian hutia specimens with archaeological specimens from the Palmetto Junction site on Providenciales located in the Turks and Caicos Islands. Bahamian hutia do not exist in the fossil record in the Turks and Caicos, indicating their translocation to the islands by humans. Our data show that individual hutia at Palmetto Junction were larger than modern specimens. This size variation may be due to anthropogenic influence; however, there is limited information regarding either natural size variation within the species or environmental factors possibly influencing size. Continued research on anthropogenic influences related to Bahamian hutia populations, coupled with isotopic studies of the Bahamian hutia diet, may further elucidate the practice of pre-Columbian management of the species.     

Oxygen isotope analysis of California mussel shells: seasonality and human sedentism at an 8,200-year-old shell midden on Santa Rosa Island,California

To evaluate coastal settlement and land use strategies among maritime hunter-gatherers, we analyzed oxygen isotope (δ¹⁸O) data from 131 marine carbonate samples from 21 California mussel (Mytilus californianus) shells obtained from a large ～8,200-year-old shell midden (CA-SRI-666) on California’s Santa Rosa Island. Seasonal distributions of the isotopic data were assigned using a paleo-sea surface temperature model created by comparing modern sea surface temperatures (SST) to a fully profiled ～8,200-year-old shell. For 20 additional shells, we used two sampling strategies to compare season-of-harvest inferences and explore whether the Early Holocene site occupants were sedentary. Estimated season-of-harvest differed by 35 % between the two sampling methods, corroborating recent isotope analysis of an 8,800-year-old shell midden on San Miguel Island. Shellfish appear to have been collected year-round at CA-SRI-666 from intertidal or subtidal water temperatures similar to modern SST in the vicinity of eastern Santa Rosa Island. The isotope results are consistent with other evidence from CA-SRI-666 that suggest that the site served as a residential base for relatively sedentary maritime people.     

THE BEAD MAKER’S MIDDEN: EVIDENCE OF LATE PREHISTORIC SHELL BEAD PRODUCTION ON OSSABAW ISLAND,GEORGIA

Abstract

In 2005, archaeological excavations were undertaken in a single shell midden at a late prehistoric Irene phase (circa A.D. 1380) site on Ossabaw Island, Georgia. The excavations were designed specifically to collect information on the fabrication of shell beads and other shell ornaments. A considerable amount of stone was recovered, almost all of which is petrified wood used specifically in the production of “microdrills” for perforating shell beads. Also recovered were large quantities of fragmented knobbed whelk (Busycon carica), the principal raw material used for shell beads, as well as examples of shell beads in all stages of manufacture. The excavations of this midden, designated the Bead Maker’s Midden, produced abundant information bearing on shellworking technology, including the full range of tools and raw materials used and the sequences involved in the production of shell beads. Replication experiments were conducted to validate the archaeological findings. The collected data provide direct evidence of the process of shell bead production during the Late Mississippi period.     

On the Possible Origins of an Unusual (Mid to Late Holocene) Coastal Deposit,Old Punt Bay,South‐East Australia

An unusual coarse, shelly sedimentary unit is found elevated above present mean sea level in a sheltered pocket embayment at Old Punt Bay in south‐eastern Australia. The coarse sediments, diverse microfauna, and large shelly macrofauna of mixed affinity suggest that the deposit is the result of high‐energy deposition. The deposit was previously thought to have been deposited 1000–1300 cal bp based on one shell dated using ¹⁴C and amino acid racemisation. However, additional ¹⁴C dating indicates a likely age of ～2500 cal bp . Regardless of age constraints, the presence of rock‐encrusting oyster shells and large articulated bivalves, suggests that the depositional event must have been capable of removing and transporting coarse sediments (rock clasts), bivalves, and oysters shells from a variety of seaward environments and depositing them with little abrasion, something storm waves are unlikely to do. The deposit may be tsunamigenic. If a tsunami origin is accepted, the new dating results indicate that it is possibly coeval with a tsunami event previously reported to have affected several other sites along the coast of New South Wales at c. 2900 cal bp . Consequently, this deposit provides evidence for the event at a new site and importantly, a tighter constraint on the likely date of the events occurrence. It further adds weight to the developing catalogue of palaeotsunamis that may have affected the south‐eastern coast of Australia. Regardless of the deposit's origins, if viewed from a coastal planning perspective, this deposit indicates that this part of the coast has experienced large‐scale overwash events in the past that if repeated, would be catastrophic. There are serious implications for risk management.     

DENTAL ATTRITION AT THE INDIAN KNOLL (15OH2) AND BLACK EARTH (11SA87) SITES: EXTREME WEAR AS A STRESSOR IN LATE ARCHAIC POPULATIONS OF THE OHIO VALLEY

Abstract

This study investigates comparatively the prospect that excessive dental wear in certain Late Archaic populations in eastern North America was caused by extensive shellfish consumption and the associated ingestion of grit. Specifically, the amount and rate of dental wear at Indian Knoll, a large shell midden site in western Kentucky, are compared to those at the Black Earth site, a contemporary occupation in southern Illinois with no evidence of shellfish utilization. Results show no significant differences in dental wear between Indian Knoll and Black Earth and point correspondingly toward the alternative prospect that the intensification of Late Archaic food-processing technology using stone-grinding and hot-rock cooking was the proximate cause. Such technologies provided short-term caloric benefits, but long-term disease consequences for adults of child-bearing age. A decrease in young adult dental wear correlates with the adoption of both food production and pottery in the subsequent Woodland period.     

The Archaeology of the Siege of Fort William, 1746

Abstract

In August and September 2007, the Centre for Battlefield Archaeology and Glasgow University Archaeological Research Division (GUARD) conducted a programme of archaeological investigation of the remains of the old fort at Fort William and part of the Parade in the town of Fort William on the west coast of Scotland. The fieldwork involved geophysical survey at the fort and the Parade, followed by trial excavation of anomalies. Trial trenches at the Parade exposed several rich midden deposits and material providing evidence for the burning of the town of Maryburgh, as suggested in contemporary accounts in 1746. The results at the fort were not so positive, as most traces of the garrison were removed in the 19th and 20th centuries through its use as a railway yard; however, a trench outside the fort suggests survival of midden deposits pre-dating this period of destruction. This part-Heritage Lottery assisted project was a Highland 2007 initiative supported by Lochaber Community Fund and Highland Council, and included active participation on the part of the local community, including school groups and metal detectorists.     

OXYGEN ISOTOPE ANALYSIS AS A MEANS OF DETERMINING SEASON OF OCCUPATION OF PREHISTORIC MIDDEN SITES

By making oxygen isotope palaeotemperature determination of successive growth increments in molluscan food-refuse shells it is possible to determine the sea temperature, and hence the season, at time of death of the shells. Although this is a method which involves the use of sophisticated and expensive equipment, it may under favourable circumstances give extremely reliable results. Shells of the limpet species Patella tabularis in the midden deposits at Nelson Bay Cave, Robberg, Cape Province, South Africa, prove to represent almost ideal material, and are used to demonstrate, contrary to what guesswork might lead one to suppose, that the site was occupied during the winter months.     

Archaeological Investigation of Military Sites on Inchkeith Island

Abstract

In August 2001, a programme of survey and trial excavation was carried out on the island of Inchkeith in the Firth of Forth in Scotland. The work was carried out as part of the first series of the BBC TV series Two Men in a Trench, and examined the WWII defences, together with some of the Victorian defences and a midden that probably dates to the 16th century.     

CONFIRMATION OF AN ARCHAIC PERIOD MOUND IN SOUTHWEST MISSISSIPPI

Abstract

Site 22LI504 is a predominantly Archaic period site in Lincoln County, Mississippi. One of its primary elements of interest is a single conical mound from which small-diameter cores revealed evidence of advanced pedogenesis. A radiocarbon sample from one soil core produced a date suggesting that the mound was Archaic in age (Fulmer 2001); however, it was unclear whether the sample came from within the mound or an underlying midden. In the spring of 2006, we excavated a 1-x-1-m unit in the mound to investigate this question. Diagnostic lithic artifacts, an advanced state of soil horizonation, and a lack of ceramics indicate that the mound is of Archaic period construction, with as many as five construction stages and artifact-rich features. We describe the soil profiles, features, and artifacts recovered from the mound, with comparisons to excavation units in an adjacent Archaic midden to show that there is no clear evidence for the mound being a functionally specific locus. We also present radiocarbon dates that indicate the earthwork is over 5,000 years old. These results are evaluated within the broader context of Archaic mound building, focusing in particular on environmental parameters underlying bet-hedging behavior.