Abstract:Coastal environments of the early mid-Holocene provided challenges and opportunities for agriculturalists living in the Santa Elena Peninsula, Ecuador (Santa Elena Province, formerly southwestern Guayas Province). Cores extracted from swamps in three river outflows, namely, the Río Verde/Río Zapotal drainage (Chanduy estuary), the Río Grande (Punta Carnero locality), and the Río Valdivia, provided pollen, phytolith, sedimentary, and elemental sequences relevant to documenting vegetation and agriculture. The Ch… Show more
“…Of the possible forms of recalcitrant carbon, phytolith–occluded carbon may fit the above criteria regarding CTO and NAO in that it is thermally resistant but not chemically resistant 29 , 30 . Indeed, phytoliths are known to dominate biogenic silica contents in the bare sediments along the length of Malaysian river estuaries 31 and have also been recorded down mangrove sediment cores 32 . Furthermore, the notable lack of phytoliths within Little Swanport’s seagrass sediments 33 is consistent with the generally similar or greater levels of BC isolated by NAO over those isolated by CTO (Fig.…”
Section: Resultsmentioning
confidence: 99%
“…As seagrasses have not been found to contain phytolith–occluded carbon 34 , 35 , its presence can also be categorised as both allochthonous and recalcitrant. However, separating mangrove phytoliths from catchment phytoliths 32 , which have no diagnostic value 35 , is a challenge that requires independent evaluation, possibly via correlations with variations in mangrove pollen. Figure 2 Black carbon content in seagrass and mangrove sediment cores from Salut–Mengkabong lagoon and Little Swanport estuary.…”
The canopies and roots of seagrass, mangrove, and saltmarsh protect a legacy of buried sedimentary organic carbon from resuspension and remineralisation. This legacy’s value, in terms of mitigating anthropogenic emissions of CO2, is based on total organic carbon (TOC) inventories to a depth likely to be disturbed. However, failure to subtract allochthonous recalcitrant carbon overvalues the storage service. Simply put, burial of oxidation-resistant organics formed outside of the ecosystem provides no additional protection from remineralisation. Here, we assess whether black carbon (BC), an allochthonous and recalcitrant form of organic carbon, is contributing to a significant overestimation of blue carbon stocks. To test this supposition, BC and TOC contents were measured in different types of seagrass and mangrove sediment cores across tropical and temperate regimes, with different histories of air pollution and fire together with a reanalysis of published data from a subtropical system. The results suggest current carbon stock estimates are positively biased, particularly for low-organic-content sandy seagrass environs, by 18 ± 3% (±95% confidence interval) and 43 ± 21% (±95% CI) for the temperate and tropical regions respectively. The higher BC fractions appear to originate from atmospheric deposition and substantially enrich the relatively low TOC fraction within these environs.
“…Of the possible forms of recalcitrant carbon, phytolith–occluded carbon may fit the above criteria regarding CTO and NAO in that it is thermally resistant but not chemically resistant 29 , 30 . Indeed, phytoliths are known to dominate biogenic silica contents in the bare sediments along the length of Malaysian river estuaries 31 and have also been recorded down mangrove sediment cores 32 . Furthermore, the notable lack of phytoliths within Little Swanport’s seagrass sediments 33 is consistent with the generally similar or greater levels of BC isolated by NAO over those isolated by CTO (Fig.…”
Section: Resultsmentioning
confidence: 99%
“…As seagrasses have not been found to contain phytolith–occluded carbon 34 , 35 , its presence can also be categorised as both allochthonous and recalcitrant. However, separating mangrove phytoliths from catchment phytoliths 32 , which have no diagnostic value 35 , is a challenge that requires independent evaluation, possibly via correlations with variations in mangrove pollen. Figure 2 Black carbon content in seagrass and mangrove sediment cores from Salut–Mengkabong lagoon and Little Swanport estuary.…”
The canopies and roots of seagrass, mangrove, and saltmarsh protect a legacy of buried sedimentary organic carbon from resuspension and remineralisation. This legacy’s value, in terms of mitigating anthropogenic emissions of CO2, is based on total organic carbon (TOC) inventories to a depth likely to be disturbed. However, failure to subtract allochthonous recalcitrant carbon overvalues the storage service. Simply put, burial of oxidation-resistant organics formed outside of the ecosystem provides no additional protection from remineralisation. Here, we assess whether black carbon (BC), an allochthonous and recalcitrant form of organic carbon, is contributing to a significant overestimation of blue carbon stocks. To test this supposition, BC and TOC contents were measured in different types of seagrass and mangrove sediment cores across tropical and temperate regimes, with different histories of air pollution and fire together with a reanalysis of published data from a subtropical system. The results suggest current carbon stock estimates are positively biased, particularly for low-organic-content sandy seagrass environs, by 18 ± 3% (±95% confidence interval) and 43 ± 21% (±95% CI) for the temperate and tropical regions respectively. The higher BC fractions appear to originate from atmospheric deposition and substantially enrich the relatively low TOC fraction within these environs.
“…Direct evidence that crops were grown in alluvial settings came from core Ch-045 in the mangrove of the Chanduy estuary (Pearsall et al 2016). Pollen was well preserved in strata radiocarbon dated 3236 BC (base of the core) to 502 BC (275 cm below the surface).…”
Section: Real Alto Agriculture: Contextualizing New Resultsmentioning
confidence: 99%
“…These issues were addressed through a program of new research incorporating (1) analysis of microfossil residues from previously excavated stone tools and human skeletal remains from Real Alto and (2) extraction and analysis of sedimentary cores from estuaries in the region. The coring study (Pearsall et al 2016) informs this article's discussion of Real Alto in its regional context. The microfossil residue research was accomplished in stages: formalizing and testing maize cob diagnostic phytoliths (Pearsall et al 2003), identifying maize phytolith and starch residues on Structure 20 tools (Pearsall et al 2004), formalizing diagnostic phytoliths for underground storage organs and other edible plant parts of economic plants and then investigating the occurrence of roots and fruits on Structure 20 tools (Chandler-Ezell et al 2006), and identifying plant residues on stone tools from three domestic and two ceremonial structures and in dental calculus samples (as discussed later).…”
Section: Real Alto In Perspectivementioning
confidence: 89%
“…Numerous earthen water-catchment features ( albarradas ) occur on the peninsula, some dated as early as the Terminal Valdivia and Chorrera (Marcos 2004; Marcos and Tobar 2004; Stothert 1995). Coring in La Tarea (LT-041), an albarrada east of Chanduy, recovered maize phytoliths in the upper 2 m (Pearsall et al 2016). Marantaceae and Canna were also present in fewer samples.…”
We investigated foodways at Real Alto, an early Formative (4400–1800 BC) Valdivia site in coastal Ecuador, using starch and phytoliths recovered from 50 stone tools from three residential and two ceremonial structures, as well as 46 human dental calculus samples, to explore how food reflects the social relationships and economy of the community. Maize was important in daily meals and ceremonial foods by the Middle Valdivia (2800–2400 BC), but it was only one component of an agricultural system that included yuca, arrowroot, llerén, canna, yam, jackbean, squash, gourd, chili, and cotton. Ceremonial and everyday foods at Real Alto did not differ: actions surrounding food were both domestic and ceremonial, depending on context. Households had equal access to annual crops and to root-tubers with longer growing seasons. Gelatinized starch was commonly recovered on tools, indicating the processing of cooked foods. Dental calculus residues confirmed common consumption of cooked foods, fruits, and root-tubers. Cultivating crops with different water and growing season requirements necessitated diverse practices, potentially including selection of short-season varieties, hand watering, and growing crops over multiple rainy seasons. The latter two practices required increased labor inputs: access to labor was likely a key element supporting the nascent social hierarchy that emerged by the Middle Valdivia.
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