Temporal trends in stable isotopes for Nubian mummy tissues

Abstract

From Meroitic to Christian times (350 B.C.-A.D. 1400), Sudanese Nubia experienced political, economic, cultural, and environmental upheaval. Change in any one of these aspects of ancient lifeways can affect subsistence. Dietary patterns from this period are reconstructed by measuring stable carbon and nitrogen isotope ratios in tissue samples from 146 mummies excavated from five sites in the Wadi Halfa area. On average, delta 13C values of bone collagen, muscle, and skin indicate high consumption levels of C3 plants (presumably wheat or barley staples, mixed vegetables, and fruits) throughout the sequence. However, during the X-Group period (A.D. 350-550), there is a statistically significant increase in consumption of C4 plants (millet or sorghum), which are predominant in both the archeological record and in modern crop production for most of the Northern Sudan. The X-Group period was also associated with a low Nile and political and economic restructuring. Increased use of C4 plants on a seasonal basis is also indicated by shifting delta 13C values along hair shafts for both X-Group and Christian periods. delta 15N values suggest that the major source of protein for all time periods came from herbivorous animals. A small, but significant increase in 15N over the 1,000-year sequence could be the result of fertilization.

Stable isotopes and selective forces: examples in biocultural and environmental anthropology

“…After the fall of the Meroitic Kingdom, irrigation enabled the X-Group population to survive a period of increased aridity and a naturally occurring drop in the level of the Nile. Not surprisingly, isotopic data for this time period also indicate a significantly greater consumption of C 4 staples (millet and sorghum), which are much better adapted to arid conditions (White & Schwarcz 1994). Other important cultural buffering attempts included seasonal C 3 and C 4 crop rotation and food storage, where the heat-adapted but least nutritious C 4 foods were consumed in summer.…”

“…These records can only be extended across long periods of time when samples that can be correlated with each other are available. Unfortunately, many chronologies of climate and ecological change created in this way either predate human occupations of the regions involved (e.g., Brook et al 2010, Nicoll 2001, Osborne et al 2008, Stanley et al 2003 Halfa (White and Schwarcz 1994). In this case, the fertility of the Lower Nile came at the expense of the Upper Nile.…”

“…Sexual dimorphism, however, which generally signals increased stress experienced by males, decreased during the X-Group period (Vagn Neilson 1970). Isotopic data indicate that although males consumed more C 3 foods and protein from higher trophic levels than females throughout the sequence, during X-Group times their C 4 food consumption equalled that of females and the trophic level of their protein dropped (White & Schwarcz 1994). Notably, the dietary pattern that characterizes both anemia and male stress is the same.…”

“…The late beginning and long process of weaning, which occurred between 2 and 6 years of age at Wadi Halfa as indicated by δ 15 N and δ 18 O values throughout the temporal sequence, would have exerted protective effect against protein deficiency. However, since breastmilk is nutritionally inadequate for the dietary needs of children over approximately six months of age, such prolonged breastfeeding would have predisposed them to iron deficiency (White & Schwarcz 1994. Iron deficiency was endemic in childhood, as were high levels of early childhood growth disturbance, as indicated by dental pathology (Rudney 1983).…”

Mummies

“…Hair is not remodeled after it forms and hardens, and because hair grows at a relatively constant rate (roughly 1 cm a month for human scalp hair), hair enables direct measurement of past dietary intake, in a ''micro-chronological'' fashion. Hair may therefore record short-term variation in available food resources associated with seasonal changes to diet during the last few months or years of life (Sandford and Kissling, 1994;White and Schwarcz, 1994;Macko et al, 1999;O'Connell and Hedges, 1999;Mays, 2000;Wilson, 2005). New continuous flow isotope ratio mass spectrometry methods enable the isotopic measurement of relatively small masses of hair, allowing the measurement of isotopic variation along individual hairs (Sharp et al, 2003;Wilson et al, 2007).…”