54 research outputs found
Wild Food:Plants, Fish and Small Animals on the Menu for Early Holocene Populations at al-Khiday, Central Sudan
Al Khiday, located on the bank of the White Nile in Sudan, offers an exceptionally preserved stratigraphic sequence, providing a unique opportunity to use organic residue analysis to investigate diet and subsistence over the full course of the Khartoum Mesolithic together with possible continuity or change into the Early Neolithic, a period of nearly 3000 years (8900-6000 cal BP). Whilst the vast and diverse Mesolithic fish assemblage indicates a strong reliance on products from aquatic habitats, floodplains, vegetated marshes and open water, results from the lipid residue analysis suggest that the fish were not cooked in the pots, likely being consumed in other ways. Rather, pots were more specialised in processing plants, wild grasses, leafy plants and sedges, confirmed by experimental analysis, and for the first time, providing direct chemical evidence for plant exploitation in the Khartoum Mesolithic. Non-ruminant fauna, such as warthog and low lipid-yielding reptiles such as Adanson’s mud turtle and Nile monitor lizard, which were found in significant numbers at al-Khiday, were also cooked in pots. There is little evidence for the processing of wild ruminants in the pots, suggesting either that ruminant species were not routinely hunted, or, that large wild fauna may have been cooked in different ways, possibly grilled over fires. These data suggest sophisticated economic strategies by sedentary people likely exploiting their ecological niche to the fullest. Pottery use changes considerably in the Early Neolithic, with ruminant products being more routinely processed in pots, and while the exploitation of domesticates cannot be confirmed by a small faunal assemblage, some dairying does take place. In summary, our results provide valuable information on Early and Middle Holocene lifeways in central Sudan
Pots, plants and animals:broad-spectrum subsistence strategies in the Early Neolithic of the Moroccan Rif region
The transition from hunter-gathering to food-producing societies in the Mediterranean zone of north Africa was complex and variable, likely influenced by local ecological conditions as well as the socio-economic origins of the population. The adoption of domestic plants and animals was piecemeal, with hunting and gathering continuing as an important part of local subsistence strategies. Here, we investigate the timing and extent of the adoption of agricultural practices, namely herding and cultivation, in three diverse coastal and inland Early Neolithic sites in the Mediterranean Maghreb region, namely Ifri Oudadane, Ifri n’Etsedda and Hassi Ouenzga. Results from absorbed lipid residues extracted from 306 potsherds from these sites are correlated with information from faunal and archaeobotanical assemblages. Our findings suggest that agricultural practices, regarded as being of Neolithic origin, were never fully adopted in the Maghreb but rather that these farmer/foragers adopted a range of strategies including low-level food production (exploiting cereals and animal products, including meat and milk), gathering of wild plants and marine shellfish, and hunting both small and large sized game. These broad-spectrum farmer/foragers were clearly both flexible and resourceful and likely adapted their subsistence practices to maximise resource availability in an increasingly unpredictable environment
Early Neolithic Pits at Principal Place, Shoreditch, London Borough of Hackney
A group of four pits excavated in the upper Walbrook valley at Principal Place, Shoreditch by MOLA in 2015 produced the largest assemblage of Early Neolithic Bowl pottery recovered to date from the City of London and its immediate surrounds. The Neolithic pits had been fortuitously preserved within part of the northern extramural Roman cemetery of Londinium and conjoining sherds of Bowl pottery were also recovered from the fill of an isolated late Roman cremation. A range of analyses showed that the vessels – comprising essentially Plain Bowl with some Decorated Bowl, the latter incorporating Peterborough Ware traits – were probably locally made and had been used to process dairy products and to stew beef and mutton (though not pork). Radiocarbon dating of the lipids absorbed within the vessel walls – employing a novel technique developed at the University of Bristol – suggest that the pottery was being used in the mid-fourth millennium cal BC. The pits also contained small assemblages of struck flint, fauna (some burnt) and archaeobotanical remains (some intrusive) and may have been filled using material drawn from a long-vanished ‘pre-pit’ source, possibly a midden; they presumably represent episodic activity on the part of semi-sedentary Neolithic communities
A mechanistic hydro-epidemiological model of liver fluke risk
The majority of existing models for predicting disease risk in response to climate change are empirical. These models exploit correlations between historical data, rather than explicitly describing relationships between cause and response variables. Therefore, they are unsuitable for capturing impacts beyond historically observed variability and have limited ability to guide interventions. In this study, we integrate environmental and epidemiological processes into a new mechanistic model, taking the widespread parasitic disease of fasciolosis as an example. The model simulates environmental suitability for disease transmission at a daily time step and 25 m resolution, explicitly linking the parasite life cycle to key weather-water-environment conditions. Using epidemiological data, we show that the model can reproduce observed infection levels in time and space for two case studies in the UK. To overcome data limitations, we propose a calibration approach combining Monte Carlo sampling and expert opinion, which allows constraint of the model in a process-based way, including a quantification of uncertainty. The simulated disease dynamics agree with information from the literature, and comparison with a widely used empirical risk index shows that the new model provides better insight into the time-space patterns of infection, which will be valuable for decision support.</p
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Annual cycles of phytoplankton biomass in the subarctic Atlantic and Pacific Ocean
High-latitude phytoplankton blooms support productive fisheries and play an important role in oceanic uptake of atmospheric carbon dioxide. In the subarctic North Atlantic Ocean, blooms are a recurrent feature each year, while in the eastern subarctic Pacific only small changes in chlorophyll (Chl) are seen over the annual cycle. Here we show that when evaluated using phytoplankton carbon biomass (C[subscript]phyto) rather than Chl, an annual bloom in the North Pacific is evident and can even rival blooms observed in the North Atlantic. The annual increase in subarctic Pacific phytoplankton biomass is not readily observed in the Chl record because it is paralleled by light- and nutrient-driven decreases in cellular pigment levels (C[subscript]phyto:Chl). Specifically, photoacclimation and iron stress effects on C[subscript]phyto:Chl oppose the biomass increase, leading to only modest changes in bulk Chl. The magnitude of the photoacclimation effect is quantified using descriptors of the near-surface light environment and a photophysiological model. Iron stress effects are diagnosed from satellite chlorophyll fluorescence data. Lastly, we show that biomass accumulation in the Pacific is slower than that in the Atlantic but is closely tied to similar levels of seasonal nutrient uptake in both basins. Annual cycles of satellite-derived Chl and C[subscript]phyto are reproduced by in situ autonomous profiling floats. These results contradict the long-standing paradigm that environmental conditions prevent phytoplankton accumulation in the subarctic Northeast Pacific and suggest a greater seasonal decoupling between phytoplankton growth and losses than traditionally implied. Further, our results highlight the role of physiological processes in shaping bulk properties, such as Chl, and their interpretation in studies of ocean ecosystem dynamics and climate change.Keywords: remote sensing, phytoplanktonKeywords: remote sensing, phytoplankto
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