Pretreatment of Terrestrial Macrofossils

Norris, Margaret; Turnbull, Jocelyn; Howarth, Jamie; Vandergoes, Marcus J.

doi:10.1017/rdc.2020.8

Cited by 15 publications

(10 citation statements)

References 41 publications

(47 reference statements)

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“…Terrestrial leaf macrofossils were extracted by picking in situ material from the split core surface. Macrofossils were cleaned and pretreated using an acid-alkali-acid procedure to remove carbonates as well as fulvic and humic compounds (Norris et al, 2020). The pretreated macrofossils were converted to CO 2 by combustion, graphitized, and measured by accelerator mass spectrometry as described by Baisden et al (2013).…”

Section: Core Chronologymentioning

confidence: 99%

Using palaeolimnology to guide rehabilitation of a culturally significant lake in New Zealand

Short

Tibby

Vandergoes

et al. 2022

Aquatic Conservation

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Lakes are becoming degraded at an accelerating rate owing to human activity, and understanding their past ecology is necessary for lake management and rehabilitation. Palaeolimnology provides numerous methods that enable the historical state of lakes to be determined. New Zealand provides an ideal setting in which to do this as human modification of the landscape occurred later here than in most regions of the world (approx. 1300 CE). Lake Oporoa is a shallow lake that is highly significant to the local indigenous Māori community. This study used multiple proxy palaeolimnology to explore how lake ecology shifted following Māori and European settlement in the catchment, and how palaeolimnological data can be used to inform lake rehabilitation and conservation measures, alongside the desires of the indigenous community. Sedimentary pollen, diatoms, bacterial communities, and elemental and hyperspectral imaging scanning were used to infer ecological changes in the lake and catchment from pre‐human times to present. Following Māori settlement (approx. 1620 CE) there was gradual vegetation change and a rapid shift in diatom and bacterial assemblages, but not in phytoplankton pigments or sediment geochemistry. An increasing abundance of diatom taxa Discostella stelligera and Staurosirella cf. ovata indicates early nutrient enrichment. European pastoralism from approximately 1840 CE resulted in further deforestation, and all proxies show evidence for enhanced primary productivity driven by a combination of nutrient enrichment and changing lake levels, particularly since the 1960s. This has caused degradation in water quality and is likely to have contributed to the decline in populations of tuna (eel, Anguilla spp.). Conversations with local Māori, together with the palaeolimnological results, indicate that a culturally acceptable and realistic rehabilitation target for Lake Oporoa aligns with ecological conditions in the 1950s. The palaeoecological data provide information to guide catchment and lake revegetation and other methods of nutrient abatement, with the eventual aim of restoring culturally important tuna and native fish populations.

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Section: Core Chronologymentioning

confidence: 99%

Using palaeolimnology to guide rehabilitation of a culturally significant lake in New Zealand

Short

Tibby

Vandergoes

et al. 2022

Aquatic Conservation

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“…However, which method is the most suitable remains a matter of debate, though some methodological trials that have compared the main pre-treatment techniques (Acid Oxidation [ABOX] and Acid-Alkaline-Acid or Acid-Base-Acid [AAA or ABA]) have concluded that the former produces superior results to the latter (Haesaerts et al, 2013;Maroto et al, 2012). This finding has been corroborated by a recent study (Norris et al, 2020) which analyses the different varieties of AAA pre-treatment in detail, and concluded that they should involve more than the simple application of acid to the sample.…”

Section: Sample Pre-treatment / Ultrafiltration: a New Problem?mentioning

confidence: 91%

Dating prehispanic and colonial sites on the island of Gran Canaria: a proposal for a radiocarbon hygiene protocol

Gordó¹,

Marrero²,

Vidal-Matutano³

et al. 2022

tabona

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Radiocarbon dating can give rise to problems associated with the nature of the dated sample, with the method used itself and with the stratigraphic reliability of the dated site. Consequently, the principal objective of this paper is to carry out a systematic exploration of each of these aspects. To this end, a critical review was conducted of the radiocarbon dates of materials from archaeological sites on the island of Gran Canaria. On the basis of this analysis, a system of categories of radiometric reliability was developed and, simultaneously, objective analytical criteria were used in an attempt to establish the reliability of radiometric dates obtained for archaeological sites in the Canary Islands and, in particular, the island of Gran Canaria.

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“…Targets for 14 C dating were limited to terrestrial leaf macrofossils collected by picking from the split core surface or by sieving sequential 1-cm core slices. Macrofossils were cleaned of residual sediment under a dissecting microscope and chemically pretreated to remove carbonates, fulvic and humic compounds using an acid-alkaline-acid pretreatment (Norris et al, 2020). Using the protocol described by Baisden et al (2013), the cleaned macrofossils were converted to CO 2 by combustion, graphitized, and measured by accelerator mass spectrometry at the Rafter Laboratory.…”

Section: Sediment Core Chronologymentioning

confidence: 99%

Detection of fish and mussel DNA in lake sediment cores depends on location, species, and molecular method

Thomson‐Laing,

Howarth,

Atalah

et al. 2023

Environmental DNA

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Environmental DNA provides an opportunity to track long‐term changes in biological communities in lake ecosystems but the detection of macroorganisms, such as freshwater fish and mussels, in sedimentary DNA (sedDNA) has only been successfully reported in a few studies to date. Factors such as low abundance of the target organisms, sampling location, the molecular approach used, and DNA quantity may influence detection, though studies exploring these factors are lacking. In the present study, sediment cores were collected from a depocenter and nearshore site in a small shallow lake where some historical fish survey data was available. DNA was extracted from the sediment core and analyzed for Anguilla australis (shortfin eel), Echyridella menziesii (freshwater mussel), and Perca fluviatilis (European perch) using droplet digital PCR (ddPCR) and general fish (class Actinopterygii) and macroinvertebrates using metabarcoding. The data from the historical fish surveys (last 20 years) aligned with the molecular data except for a lack of Anguilla dieffenbachii (longfin eel) DNA detection. Generalized additive mixed model analysis showed significantly higher detections in samples from the nearshore compared to depocenter core, which is most likely related to habitat of the target species. Differential detection of target species was likely caused by their ecology and locality. The ddPCR assays were more sensitive (88 ± 3% of samples with positive detections) than metabarcoding (48 ± 10%). However, the metabarcoding enabled the detection of additional fish species. Target species detection was negatively impacted by a reduction in total DNA concentration in older sediments. This research highlights that current molecular techniques used to target fish and mussel sedDNA can result in inconsistent temporal and spatial detection of species, especially in older sediments. We recommend that the methodology and interpretation of sedDNA results need to be considered in the context of species ecology, abundance, and DNA concentrations.

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Pretreatment of Terrestrial Macrofossils

Cited by 15 publications

References 41 publications

Using palaeolimnology to guide rehabilitation of a culturally significant lake in New Zealand

Using palaeolimnology to guide rehabilitation of a culturally significant lake in New Zealand

Dating prehispanic and colonial sites on the island of Gran Canaria: a proposal for a radiocarbon hygiene protocol

Detection of fish and mussel DNA in lake sediment cores depends on location, species, and molecular method

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