Paleomobility in the Tiwanaku Diaspora: Biogeochemical analyses at Rio Muerto,Moquegua, Peru

Paleomobility has been a key element in the study of the expansion of ancient states and empires, including the Tiwanaku polity of the South Central Andes (AD 500–1000). We present radiogenic strontium and oxygen isotope data from human burials from three cemeteries in the Tiwanaku‐affiliated Middle Horizon archaeological site complex of Rio Muerto in the Moquegua Valley of southern Peru. At Rio Muerto, archaeological human enamel and bone values range from ⁸⁷Sr/⁸⁶Sr = 0.70657–0.72018, with a mean of ⁸⁷Sr/⁸⁶Sr = 0.70804 ± 0.00207 (1σ, n = 55). For the subset of samples analyzed for oxygen isotope values (n = 48), the data ranges from δ¹⁸O_{carbonate(VSMOW)} = +18.1 to +27.0‰. When contextualized with other lines of archaeological evidence, we interpret these data as evidence for an archaeological population in which the majority of individuals had “local” origins, and were likely second‐generation, or more, immigrants from the Tiwanaku heartland in the altiplano. Based on detailed life history data, we argue a smaller number of individuals came at different ages from various regions within the Tiwanaku polity. We consider whether these individuals with isotopic values consistent with “nonlocal” geographic origins could represent first‐generation migrants, marriage exchange partners, or occupationally mobile herders, traders or other travelers. By combining isotopic life history studies with mortuary treatment data, we use a person‐centered migration history approach to state integration and expansion. Isotopic analyses of paleomobility at the Rio Muerto site complex contribute to the role of diversity in ancient states by demonstrating the range of geographic origins rather than simply colonists from the Lake Titicaca Basin. Am J Phys Anthropol 155:405–421, 2014. © 2014 Wiley Periodicals, Inc.     

Stable and radiogenic isotope analyses on shark teeth from the Early to the Middle Permian (Sakmarian–Roadian) of the southwestern USA

δ¹⁸O_P values and ⁸⁷Sr/⁸⁶Sr ratios were determined on disarticulated xenacanthiform, hybodontid and ctenacanthid shark tooth material from several Early Permian (Sakmarian–Kungurian) continental bone beds of northern Texas and southern Oklahoma as well as from the marine Middle Permian (Roadian) of northern Arizona. The δ¹⁸O_P values derived from the teeth of bone beds are in the range of 17.6–23.5‰ VSMOW, and are mostly depleted in ¹⁸O by 0.5–5‰ relative to proposed coeval marine δ¹⁸O_P values. This indicates an adaptation to freshwater habitats on the Early Permian coastal plain by several sharks. Distinctly higher δ¹⁸O_P values from two bone beds are attributed to significant evaporative enrichment in ¹⁸O in flood plain ponds. ⁸⁷Sr/⁸⁶Sr ratios of around 0.71077 are notably more radiogenic than ⁸⁷Sr/⁸⁶Sr of contemporaneous seawater. In contrast, the isotopic composition of teeth from the marine Kaibab Formation is characterised by low δ¹⁸O_P values in the range of 13.4–15.6‰ VSMOW while ⁸⁷Sr/⁸⁶Sr ratios of around 0.70821 are closer to the Roadian seawater value. The distinctly depleted δ¹⁸O_P values cannot be readily explained by fluvially affected freshening in a nearshore marine environment, so a diagenetic alteration of the Kaibab material seems to be more likely, excluding it from further interpretation.     

Foraminiferal oxygen and carbon isotopes during the last 34 kyr off northern Japan,northwestern Pacific

Oxygen and carbon isotopes of foraminifera were analyzed in core PC4, water depth 1366 m, off northern Japan, near the east side of the Tsugaru Strait (130 m depth) between the open northwestern Pacific Ocean and the Japan Sea. At present, the site is at the confluence of the Tsugaru Warm Current which flows eastwards out of the Sea of Japan through the Tsugaru Strait, the subarctic Oyashio Current and the subtropic Kuroshio Current. During the Last Glacial Maximum (LGM), the Oyashio Current penetrated further to the South and outflow from the Japan Sea was restricted by glacio-eustatic sea level lowering.The isotopic values of the planktic foraminifer Neogloboquadrina pachyderma (sinistral) and the benthic foraminifer Uvigerina akitaensis reflect rapid millennial-scale paleoceanographic changes between 34 and 6 ka. Hydrographic changes during deglaciation were related to events at high northern latitudes, but Holocene hydrographic changes were dominated by local effects, such as the development of the outflow of the Tsugaru Warm Current. High values of planktic δ¹⁸O during the LGM reflect the southward advance of the Oyashio Current. These values decreased by 0.3‰ from 19.4 to 18.9 ka, then increased by 0.5‰ at 18 ka, with highest values between 17.5 and 15 ka. The δ¹⁸O oscillations between 19.4 and 15 ka may reflect millennial-scale warm–cold oscillations during Heinrich event 1. Planktic microfossil data indicate that cold Oyashio waters flowed from the northwestern Pacific into the Japan Sea via the Tsugaru Strait between 17 and 16 ka, consistent with the occurrence of the highest planktic δ¹⁸O values in core PC4. Planktic δ¹⁸O values rapidly decreased by 0.9‰ at 15 ka, possibly reflecting the effects of both a rapid increase in fresh water flux and rising temperatures in the subarctic North Pacific. During the Younger Dryas, cold event planktic δ¹⁸O values increased by 0.5‰, followed by a gradual decrease by 1‰ from the early to middle Holocene, reflecting a gradual increase in eastward outflow via the Tsugaru Strait with sea level rise. Both planktic and benthic foraminiferal δ¹³C values oscillated between 34 and 10 ka, at relatively large amplitudes (about 0.5‰), then remained relatively stable during the last 10 kyr. Several negative planktic and benthic (∼ − 0.7‰) δ¹³C excursions were present in sediment dated between the precipitation of secondary carbonates during episodic methane release possibly associated with methane release from continental margin sediments.     

Ecology and physiology of White River mammals based on stable isotope ratios of teeth

To characterize the ecology and physiology of common late Eocene–early Oligocene White River mammals, we analyzed the carbon and oxygen isotope composition of tooth enamel carbonate for six of the most abundant taxa: the perissodactyls Brontops (brontothere), Mesohippus (equid) and Subhyracodon (rhino); and the artiodactyls Merycoidodon (oreodont), Leptomeryx (leptomerycid) and Poebrotherium (camelid).δ¹³C values of middle and rear molars (M2s and M3s) and premolars range from ? 13.1‰ to ? 7.7‰ (V-PDB), consistent with pure C3 diets. In the late Eocene, Mesohippus, Merycoidodon, and Leptomeryx show indistinguishable average δ¹³C values (～ ? 10‰). In contrast, Brontops and Subhyracodon exhibit lower (? 11.2‰) and higher (? 8.7‰) values, respectively. Early Oligocene values for Mesohippus and Merycoidodon remain indistinguishable from each other and lower than the value of Leptomeryx, Poebrotherium, and Subhyracodon (～ ? 8.5‰). These results likely indicate niche separation in terms of habitat preference between the investigated sympatric taxa. More specifically, assuming a δ¹³C value of atmospheric CO₂ of ? 5.5‰, our data suggest a preference of Brontops for mesic forested areas, of Mesohippus and Merycoidodon for woodlands, and of Subhyracodon and Poebrotherium for more open habitats (e.g., grasslands). The higher Oligocene versus Eocene average δ¹³C exhibited by Leptomeryx possibly reflects a preference of the new Oligocene species L. evansi for more open and/or xeric habitats relative to the Eocene species L. speciosus.Late Eocene and early Oligocene average δ¹⁸O of Mesohippus, Merycoidodon, Leptomeryx, and Subhyracodon are similar (～ 25‰, V-SMOW), possibly indicating comparable water dependency for these taxa. In contrast, the higher δ¹⁸O of Poebrotherium (26.6‰) suggests lower water dependency whereas the lower δ¹⁸O of Brontops (23.0‰) may result from a high water dependency or, more likely, from its preference for humid habitats. Because hind-gut fermentation in perissodactyls requires high water intake, whereas fore-gut fermentation does not, our results might indicate the presence of fore-gut fermentation in early Oligocene camelids but its absence or incomplete development in late Eocene–early Oligocene oreodonts and leptomerycids.     

Diurnal variation in the stable isotope composition of water and dry matter in fruiting Lupinus angustifolius under field conditions

In this paper, we present an integrated account of the diurnal variation in the stable isotopes of water (δD and δ¹⁸O) and dry matter (δ¹⁵N, δ¹³C, and δ¹⁸O) in the long‐distance transport fluids (xylem sap and phloem sap), leaves, pod walls, and seeds of Lupinus angustifolius under field conditions in Western Australia. The δD and δ¹⁸O of leaf water showed a pronounced diurnal variation, ranging from early morning minima near 0‰ for both δD and δ¹⁸O to early afternoon maxima of 62 and 23‰, respectively. Xylem sap water showed no diurnal variation in isotopic composition and had mean values of ?13·2 and ?2·3‰ for δD and δ¹⁸O. Phloem sap water collected from pod tips was intermediate in isotopic composition between xylem sap and leaf water and exhibited only a moderate diurnal fluctuation. Isotopic compositions of pod wall and seed water were intermediate between those of phloem and xylem sap water. A model of average leaf water enrichment in the steady state (Craig & Gordon, pp. 9–130 in Proceedings of a Conference on Stable Isotopes in Oceanographic Studies and Palaeotemperatures, Lischi and Figli, Pisa, Italy, 1965; Dongmann et al., Radiation and Environmental Biophysics 11, 41–52, 1974; Farquhar & Lloyd, pp. 47–70 in Stable Isotopes and Plant Carbon–Water Relations, Academic Press, San Diego, CA, USA, 1993) agreed closely with observed leaf water enrichment in the morning and early afternoon, but poorly during the night. A modified model taking into account non‐steady‐state effects (Farquhar and Cernusak, unpublished) gave better predictions of observed leaf water enrichments over a full diurnal cycle. The δ¹⁵N, δ¹³C, and δ¹⁸O of dry matter varied appreciably among components. Dry matter δ¹⁵N was highest in xylem sap and lowest in leaves, whereas dry matter δ¹³C was lowest in leaves and highest in phloem sap and seeds, and dry matter δ¹⁸O was lowest in leaves and highest in pod walls. Phloem sap, leaf, and fruit dry matter δ¹⁸O varied diurnally, as did phloem sap dry matter δ¹³C. These results demonstrate the importance of considering the non‐steady‐state when modelling biological fractionation of stable isotopes in the natural environment.     

Taxon-specific variation in the stable isotopic signatures (δ13C and δ15N) of lake phytoplankton

1. The variability in the stable isotope signatures of carbon and nitrogen (δ¹³C and δ¹⁵N) in different phytoplankton taxa was studied in one mesotrophic and three eutrophic lakes in south‐west Finland. The lakes were sampled on nine to 16 occasions over 2–4 years and most of the time were dominated by cyanobacteria and diatoms. A total of 151 taxon‐specific subsamples covering 18 different phytoplankton taxa could be isolated by filtration through a series of sieves and by flotation/sedimentation, followed by microscopical identification and screening for purity. 2. Substantial and systematic differences between phytoplankton taxa, seasons and lakes were observed for both δ¹³C and δ¹⁵N. The values of δ¹³C ranged from ?34.4‰ to ?5.9‰ and were lowest in chrysophytes (?34.4‰ to ?31.3‰) and diatoms (?30.6‰ to ?26.6‰). Cyanobacteria were most variable (?32.4‰ to ?5.9‰), including particularly high values in the nostocalean cyanobacterium Gloeotrichia echinulata (?14.4‰ to ?5.9‰). For δ¹³C, the taxon‐specific amplitude of temporal changes within a lake was usually <1–8‰ (<1–4‰ for microalgae alone and <1–8‰ for cyanobacteria alone), whereas the amplitude among taxa within a water sample was up to 31‰. 3. The values of δ¹⁵N ranged from ?2.1‰ to 12.8‰ and were high in chrysophytes, dinophytes and diatoms, but low in the nitrogen‐fixing cyanobacteria Anabaena spp., Aphanizomenon spp. and G. echinulata (?2.1‰ to 1.6‰). Chroococcalean cyanobacteria ranged from ?1.4‰ to 8.9‰. For δ¹⁵N, the taxon‐specific amplitude of temporal changes within a lake was 2–6‰, (2–6‰ for microalgae alone and 2–4‰ for cyanobacteria alone) and the amplitude among taxa within a water sample was up to 11‰. 4. The isotopic signatures of phytoplankton changed systematically with their physical and chemical environment, most notably with the concentrations of nutrients, but correlations were non‐systematic and site‐specific. 5. The substantial variability in the isotopic signatures of phytoplankton among taxa, seasons and lakes complicates the interpretation of isotopic signatures in lacustrine food webs. However, taxon‐specific values and seasonal patterns showed some consistency among years and may eventually be predictable.     

Identifying groundwater‐fed climate refugia in remote arid regions with citizen science and isotope hydrology

1. Groundwater and surface water‐fed systems act as biodiversity hotspots and ecological refuges and evolutionary refugia in arid regions. Groundwater‐dominated systems are sustained by underground aquifers that are recharged by rain that has fallen in the distant past, while surface water‐dominated systems are fed by recent local rain or floods. Some waterbodies are fed by a mixture of these sources. Perennial, groundwater‐dominated systems will act as refuges and refugia under future rainfall declines associated with global warming. We sought to identify climate refugia, based on groundwater dominance, by using isotope hydrology to characterise water samples collected by citizen scientists across arid central Australia.
2. There is a linear relationship between hydrogen isotopes (²H/¹H, δ²H) and oxygen isotopes (¹⁸O/¹⁶O, δ¹⁸O) in rainfall. This relationship is known as the meteoric water line (MWL). By comparing our samples with the Australian MWL, and developing a local evaporation line, we were able to test the hypotheses that groundwater‐dominated systems will follow the Australian MWL while temporary systems follow the local evaporation line, and, accordingly, distinguish between groundwater and surface water‐dominated systems. The isotopic composition of samples collected over a 36‐month period was determined using isotope ratio infrared spectrometry. The electrical conductivity of each sample was recorded to determine where freshwater is available for biota within this arid region.
3. Over 240 water samples were collected from 62 waterbodies and seven bores (groundwater wells) spanning an area of more than 250,000 km². Approximately 75% of the samples were collected by citizen scientists and 25% by research scientists.
4. Twenty groundwater‐dominated waterbodies, characterised by a small range of δ²H and δ¹⁸O values (c. ?55 to ?20‰ and c. ?9 to ?3‰, respectively) clustered around the long‐term mean composition of rainfall (δ²H = ?37.5‰, δ¹⁸O = ?6.4‰), were identified as future evolutionary refugia. These sites are likely to contain water through the most severe of droughts and will be critically important for the persistence of water‐dependent species.
5. Based on their isotopic composition, we identified 45 waterbodies (rockholes/waterholes) as temporary or ephemeral (δ²H c. ?40 to ?100‰ and δ¹⁸O c. ?4 to +25‰), that is, with no evidence of groundwater inflow. These, together with waterbodies supported by a mix of groundwater and surface water, can act as stepping stones and form part of the aquatic mosaic that is critical to supporting species in arid regions. Over two‐thirds of the waterholes sampled were very fresh (electrical conductivity <0.8 mS/cm), indicating that they provide the freshwater needed to support much of the regional aquatic and terrestrial fauna.
6. All evolutionary refugia are located within protected areas (i.e. national parks or Indigenous Protected Areas), but some are subject to the impacts of feral animal species and invasive plants. Our findings indicate where control programmes and restoration actions can be prioritised to support biodiversity conservation and climate change adaptation. Our approach, combining citizen science and isotope hydrology, can be used to identify future refugia in other remote and arid regions where water scarcity is likely to increase under global climate change.

     

Isotopic tracing of the impact of mobility on infectious disease: The origin of people with treponematosis buried in hull,England, in the late medieval period

Treponematosis has been one of the most studied and debated infectious diseases in paleopathology, particularly from the standpoint of its origin, evolution, and transmission. This study links evidence for treponematosis in skeletons from the 14th–16th century AD cemetery of the Augustinian friary of Hull Magistrates Court, England, with data from stable isotope analysis to test the hypothesis that the people with treponemal disease buried at this site were not locally born and raised. The objective is to explore the potential of using stable isotope data to track the place of origin and extent of mobility of individuals with an infectious disease. Dental enamel samples of 12 skeletons were selected for strontium (⁸⁷Sr/⁸⁶Sr ratio) and oxygen (δ¹⁸O) stable isotope analysis based on the presence (six ‐ diseased) or absence (six ‐ controls) of bone changes associated with treponemal disease. The oxygen isotope ratios of all but three individuals (1047, 1121, 823) overlapped at two standard deviations with the inferred local precipitation range, and only one individual (1216) had a strontium isotope ratio outside the regional range. Two of the four had probable/possible treponemal bone changes. Those with treponemal bone changes were not demonstrably more likely to be migrants than those without such lesions. However, because of extensive documentary evidence for trade with the Baltic Sea area, and for merchants from towns such as Stralsund, Danzig and Elbing being in Hull, it is very plausible that the four migrants came from the Baltic area or even southern Sweden. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.     

Differences in δ13C and δ15N stable isotopes in the pearly razorfish Xyrichtys novacula related to the sex,location and spawning period

In the present study, Xyrichtys novacula (Labridae) were sampled at five locations around the islands of Ibiza and Formentera (western Mediterranean Sea). Isotopic signatures of δ¹³C, δ¹⁵N and the C:N ratio were analysed in relation to locality, sex and size differences. δ¹³C and δ¹⁵N partitioning was also studied in the reproductive spawning period. There were significant differences in the δ¹³C signature between localities for both sexes, but not for δ¹⁵N. Sex differences were also found with a mean ±s.e . value of ?17·38 ± 0·06‰δ¹³C and 8·36 ± 0·05‰δ¹⁵N for females and ?17·17 ± 0·07‰δ¹³C and 8·80 ± 0·06‰δ¹⁵N for males. Increasing total length in both sexes was positively correlated with δ¹⁵N enrichment and a significant positive linear regression was established for both variables. During the reproductive spawning period, there were changes in δ¹³C fractioning with enrichment in postspawning females and males (with respect to prespawning and spawning periods) and δ¹⁵N impoverishment in postspawning females (with respect to prespawning and spawning periods). Xyrichtys novacula uses local food sources, as confirmed by δ¹³C and δ¹⁵N, and females and males use different food sources, thus avoiding intraspecific competition. This was confirmed by δ¹⁵N enrichment as size increased. Spawning leads to special requirements for gonad maturation, which is reflected in the isotopic signatures for both sexes.     

Investigating cultural heterogeneity in San Pedro de Atacama,northern Chile,through biogeochemistry and bioarchaeology

Individuals living in the San Pedro de Atacama oases and the neighboring upper Loa River Valley of northern Chile experienced the collapse of an influential foreign polity, environmental decline, and the appearance of a culturally distinct group during the Late Intermediate Period (ca. AD 1,100–1,400). We investigate cultural heterogeneity at the Loa site of Caspana through analyses of strontium and oxygen isotopes, cranial modification styles, and mortuary behavior, integrating biological aspects of identity, particularly geographic origins, with cultural aspects of identity manifested in body modification and mortuary behavior. We test the hypothesis that the Caspana population (n = 66) represents a migrant group, as supported by archeological and ethnographic evidence, rather than a culturally distinct local group. For Caspana archeological human tooth enamel, mean ⁸⁷Sr/⁸⁶Sr = 0.70771 ± 0.00038 (1σ, n = 30) and mean δ¹⁸O_c(V‐PDB) = ?3.9 ± 0.6‰ (1σ, n = 16); these isotopic data suggest that only one individual lived outside the region. Material culture suggests that the individuals buried at Caspana shared some cultural affinity with the San Pedro oases while maintaining distinct cultural traditions. Finally, cranial modification data show high frequencies of head shaping [92.4% (n = 61/65)] and an overwhelming preference for annular modification [75.4% (n = 46/61)], contrasting sharply with practices in the San Pedro area. Based on multiple lines of evidence, we argue that, rather than representing a group of altiplano migrants, the Caspana population existed in the region for some time. However, cranial modification styles and mortuary behavior that are markedly distinct from patterns in surrounding areas raise the possibility of cultural heterogeneity and cultural fissioning. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

“Celtic migrations”: Fact or fiction? Strontium and oxygen isotope analysis of the Czech cemeteries of Radovesice and Kutná Hora in Bohemia

Strontium and oxygen isotope analysis of human remains from the early La Tène (fourth/third century BC) Czech cemeteries of Radovesice I (RAD I), Radovesice II (RAD II), and Kutná Hora were conducted to investigate the importance of residential changes during the period of the historic “Celtic migrations”. In the initial phases (LT A/B), the grave goods of these cemeteries are typical for the core area of the La Tène culture, while around 300 BC (LT B2) an alteration occurs and typical Bohemian styles arise, and connections to Moravia and the Danubian region become visible. The strontium isotope ratios are highly varied with ⁸⁷Sr/⁸⁶Sr values between 0.7062 and 0.7153 in Radovesice, and between 0.7082 and 0.7147 in Kutná Hora. The oxygen isotope data are more homogeneous and yield δ¹⁸O_p ratios from 14.8‰ to 17.2‰ [mean: 16.2‰ ± 0.5 (1σ)] in Radovesice, and from 14.9‰ to 17.3‰ [mean: 16.5‰ ± 0.6 (1σ)] in Kutná Hora. Because the geological properties of the landscapes around the sites are variable and complex, most of the observed variations among the strontium isotope ratios may have been caused by agricultural practices, such as regularly changing farming land. Nevertheless, there are some individuals who differ completely from the regional isotopic baseline values. This suggests that at least a small part of the community migrated, which does not seem to be correlated with any particular phase of the La Tène period. Remarkably, it is mainly males who seem to be of nonlocal origin, and particularly those who were buried as warriors. Females, on the other hand, appear to have been more closely bonded to the Bohemian region. Whether the “foreign” individuals with differing isotopic compositions came from Moravia or the Danubian region remains debatable. Am J Phys Anthropol 155:496–512, 2014. © 2014 Wiley Periodicals, Inc.     

Kangaroo tooth enamel oxygen and carbon isotope variation on a latitudinal transect in southern Australia: implications for palaeoenvironmental reconstruction

Tooth enamel apatite carbonate carbon and oxygen isotope ratios of modern kangaroos (Macropus spp.) collected on a 900-km latitudinal transect spanning a C₃–C₄ transition zone were analysed to create a reference set for palaeoenvironmental reconstruction in southern Australia. The carbon isotope composition of enamel carbonate reflects the proportional intake of C₃ and C₄ vegetation, and its oxygen isotope composition reflects that of ingested water. Tooth enamel forms incrementally, recording dietary and environmental changes during mineralisation. Analyses show only weak correlations between climate records and latitudinal changes in δ¹³C and δ¹⁸O. No species achieved the δ¹³C values (~?1.0 ‰) expected for 100 % C₄ grazing diets; kangaroos at low latitudes that are classified as feeding primarily on C₄ grasses (grazers) have δ¹³C of up to ?3.5 ‰. In these areas, δ¹³C below ?12 ‰ suggests a 100 % C₃ grass and/or leafy plant (browse) diet while animals from higher latitude have lower δ¹³C. Animals from semi-arid areas have δ¹⁸O of 34–40 ‰, while grazers from temperate areas have lower values (~28–30 ‰). Three patterns with implications for palaeoenvironmental reconstruction emerge: (1) all species in semi-arid areas regularly browse to supplement limited grass resources; (2) all species within an environmental zone have similar carbon and oxygen isotope compositions, meaning data from different kangaroo species can be pooled for palaeoenvironmental investigations; (3) relatively small regional environmental differences can be distinguished when δ¹³C and δ¹⁸O data are used together. These data demonstrate that diet–isotope and climate–isotope relationships should be evaluated in modern ecosystems before application to the regional fossil record.     

Tarbellastraea (Scleractinia): A new stable isotope archive for Late Miocene paleoenvironments in the Mediterranean

Geochemical proxy records of sea surface temperature (SST) or sea surface salinity (SSS) variability on intra- and interannual time-scales in corals from geological periods older than Pleistocene are extremely rare due to pervasive diagenetic alteration of coralline aragonite. Very recently, however, stable isotope data (δ¹⁸O, δ¹³C) from specimens of Porites of Late Miocene age (10 Ma) have been shown to preserve original environmental signatures. In this paper we describe new finds of the zooxanthellate corals Porites and Tarbellastraea in exceptional aragonite preservation from the island of Crete in sediments of Tortonian (～ 9 Ma) and Early Messinian (～ 7 Ma) age. Systematic, comparative stable isotope analysis of massive Tarbellastraea and Porites sampled from the same beds and localities reveal identical stable isotope fractionation patterns in both genera. Therefore, extinct Tarbellastraea represents an additional environmental archive fully compatible and mutually exchangeable with Porites. Provided that seasonal variations in δ¹⁸O reflect SST changes only, seasonal SST contrasts of 7.3 °C for the Tortonian and 4.8 °C for the Early Messinian are inferred, implying warmer summer and cooler winter SSTs during the Tortonian than during the Messinian. However, reduced δ¹⁸O seasonality (1.1‰ in the Tortonian and 0.7‰ in the Messinian) and slightly less negative mean δ¹⁸O in Messinian corals (? 2.4‰) compared to Tortonian specimens (? 2.7‰) may not necessarily indicate a long-term fall in SSTs, but changes in surface water δ¹⁸O, i.e. global ice build-up or enhanced evaporation during summer or increased precipitation/river discharge during winter and changes in insolation. On the other hand, coral communities of Tortonian and Messinian age in central Crete are identical, and compatible annual extension rates indicate similar average SSTs during the two investigated time periods. In addition, lithological and paleobotanical data from Central Crete document a change from humid to dry climatic conditions during the Late Miocene. Therefore, a likely explanation for the observed shift in coral mean δ¹⁸O and reduced δ¹⁸O seasonality from the Tortonian to the Early Messinian is a change in ambient seawater δ¹⁸O caused by a change in the hydrological balance towards high evaporation/high salinity during summer.     

Disentangling CO2 fluxes: direct measurements of mesocosm‐scale natural abundance 13CO2/12CO2 gas exchange, 13C discrimination,and labelling of CO2 exchange flux components in controlled environments

A ¹³C/¹²C mass spectrometer was interfaced with a open gas exchange system including four growth chambers to investigate CO₂ exchange components of perennial ryegrass (Lolium perenne L.) stands. Chambers were fed with air containing CO₂ with known δ¹³C (δ_CΟ2?2.6 or ?46.8‰). The system did not fractionate C isotopes and no extraneous CO₂ leaked into chambers. The on‐line ¹³C discrimination (Δ) of ryegrass stands in light was independent of δ_CΟ2 when δ_CΟ2 was constant. The δ of CO₂ exchanged by the stands in light (δ_Nd) and darkness (δ_Rn) differed by 0.7‰, suggesting some Δ in dark respiration at the stand‐level. However, Δ decreased by ～ 10‰ when δ_CΟ2 was switched from ?46.8 to ?2.5‰, and increased by ～ 10‰ following a shift from ?2.6 to ?46.7‰ due to isotopic disequilibria between photosynthetic and respiratory fluxes. Isotopic imbalances were used to assess (non‐photorespiratory) respiration in light and the replacement of the respiratory substrate pool(s) by new photosynthate. Respiration was partially inhibited by light, but increased during the light period and decreased in darkness, in association with temperature changes. The labelling kinetics of respiratory CO₂ indicated the existence of two major respiratory substrate pools: a fast pool which was exchanged within hours, and a slow pool accounting for ～ 60% of total respiration and having a mean residence time of 3.6 d.     

"These boots were made for walking": the isotopic analysis of a C(4) Roman inhumation from Gravesend, Kent, UK

As part of the road widening scheme between London and Dover, Oxford Archaeology South uncovered a large boundary ditch of Iron Age origin that contained Iron Age and Roman inhumations, adjacent to which was a small mid-late Roman cemetery, interpreted as a rural cemetery for Romano-British farmers. Grave goods in the cemetery were restricted to a few individuals with hobnailed boots. Bulk bone collagen isotopic analysis of 11 skeletons of Iron Age and Roman date gave a typical C(3) terrestrial signal (average δ(13) C = -19.8‰, δ(15) N = 9.3‰), but also revealed one (SK12671) with a diet which included a substantial C(4) component (δ(13) C = -15.2‰, δ(15) N = 11.2‰). This is only the second such diet reported in Roman Britain. Subsequent δ(18) O(c) and (87) Sr/(86) Sr measurements on the dental enamel in this individual were, however, consistent with a "local" origin, indicating that either C(4) protein was consumed in Late Roman Britain, or that he came from somewhere else, but where conditions gave rise to similar isotopic values. If we accept the latter, then it indicates that using oxygen and strontium isotopes alone to identify "incomers" may be problematic. The provision of hobnailed boots for the dead appears to have had a strong symbolic element in Late Roman Britain. We suggest that in this case the boots may be significant, in that he was being equipped for the long march home.     

Dentine oxygen isotopes (δ18O) as a proxy for odontocete distributions and movements

Spatial variation in marine oxygen isotope ratios (δ¹⁸O) resulting from differential evaporation rates and precipitation inputs is potentially useful for characterizing marine mammal distributions and tracking movements across δ¹⁸O gradients. Dentine hydroxyapatite contains carbonate and phosphate that precipitate in oxygen isotopic equilibrium with body water, which in odontocetes closely tracks the isotopic composition of ambient water. To test whether dentine oxygen isotope composition reliably records that of ambient water and can therefore serve as a proxy for odontocete distribution and movement patterns, we measured δ¹⁸O values of dentine structural carbonate (δ¹⁸O_SC) and phosphate (δ¹⁸O_P) of seven odontocete species (n = 55 individuals) from regional marine water bodies spanning a surface water δ¹⁸O range of several per mil. Mean dentine δ¹⁸O_SC (range +21.2 to +25.5‰ VSMOW) and δ¹⁸O_P (+16.7 to +20.3‰) values were strongly correlated with marine surface water δ¹⁸O values, with lower dentine δ¹⁸O_SC and δ¹⁸O_P values in high‐latitude regions (Arctic and Eastern North Pacific) and higher values in the Gulf of California, Gulf of Mexico, and Mediterranean Sea. Correlations between dentine δ¹⁸O_SC and δ¹⁸O_P values with marine surface water δ¹⁸O values indicate that sequential δ¹⁸O measurements along dentine, which grows incrementally and archives intra‐ and interannual isotopic composition over the lifetime of the animal, would be useful for characterizing residency within and movements among water bodies with strong δ¹⁸O gradients, particularly between polar and lower latitudes, or between oceans and marginal basins.     

Oxygen isotope fractionation between crocodilian phosphate and water

Oxygen isotope compositions of phosphate (δ¹⁸O_p) were measured in tooth enamel from captive and wild individuals of 8 crocodilian species. A rough linear correlation is observed between the δ¹⁸O_p of all the studied species and the oxygen isotope composition of ambient water (δ¹⁸O_w). Differences in mean air temperature, diet and physiology could contribute significantly to the large scatter of δ¹⁸O_p values. The combination of these parameters results in a fractionation equation for which the slope (0.82) is lower than that expected (≥ 1) from predictive model equations that assume temperature and diet as fixed parameters. Taking into account large uncertainties, the observed oxygen isotope fractionation between phosphate and ambient water does not statistically differ from that formerly established for aquatic turtles. Case studies show that δ¹⁸O_p values of fossil crocodile tooth enamel can be used to discriminate between marine and freshwater living environments within a precision of about ± 2‰ only.     

Belemnite ecology and the environment of the Nusplingen Plattenkalk (Late Jurassic,southern Germany): evidence from stable isotope data

The late Kimmeridgian Nusplingen Plattenkalk (palaeolatitude ~30°N) is one of the well‐known European Plattenkalk konservatlagerstätten. The laminated limestones of this lagerstätte have been deposited in a shallow lagoon, surrounded by sponge‐microbial mounds, some of which formed small islands. Plattenkalk sediments are often thought to have been deposited below a halocline, which was induced by high evaporation rates. By measuring the stable isotope composition of belemnite rostra (n = 27) of the species Hibolithes semisulcatus, the depositional environment of the Nusplingen Plattenkalk has been investigated. Cathodoluminescence‐microscopy and trace element analysis have been applied to check for diagenetic alteration of the studied rostra. The mean δ¹³C of the well‐preserved rostra is +0.03 ± 0.27‰, the mean δ¹⁸O ?0.68 ± 0.3‰. A narrow range of stable isotope data acquired from an accumulation of rostra, regurgitated by a fish or reptile, supports the notion that belemnite calcite reflects environmental conditions. The palaeontological and sedimentological findings suggest that H. semisulcatus was autochthonous to the Nusplingen Plattenkalk. Anoxic conditions prevailed in the sediments and temporarily in the water‐column above the sediment/bottom water interface. A nektobenthic life style can be excluded for the Nusplingen belemnites; a demersal life style seems unlikely. Comparison with δ¹⁸O_bel data from other latitudes indicates that a latitudinal gradient played a role in the δ¹⁸O composition of seawater. A pelagic, inner shelf setting is therefore suggested for the Plattenkalk, an interpretation that is supported by palaeontological evidence. It is here proposed that the formation of the Nusplingen Plattenkalk was not caused by salinity stratification. It is further suggested that the belemnites were not restricted to deep‐water settings, but also occurred in shallow waters and higher in the water‐column.     

Biogeochemical probing of microbial communities in a basalt‐hosted hot spring at Kverkfjöll volcano,Iceland

We investigated bacterial and archaeal communities along an ice‐fed surficial hot spring at Kverkfjöll volcano—a partially ice‐covered basaltic volcano at Vatnajökull glacier, Iceland, using biomolecular (16S rRNA, apsA, mcrA, amoA, nifH genes) and stable isotope techniques. The hot spring environment is characterized by high temperatures and low dissolved oxygen concentrations at the source (68°C and <1 mg/L (±0.1%)) changing to lower temperatures and higher dissolved oxygen downstream (34.7°C and 5.9 mg/L), with sulfate the dominant anion (225 mg/L at the source). Sediments are comprised of detrital basalt, low‐temperature alteration phases and pyrite, with <0.4 wt. % total organic carbon (TOC). 16S rRNA gene profiles reveal that organisms affiliated with Hydrogenobaculum (54%–87% bacterial population) and Thermoproteales (35%–63% archaeal population) dominate the micro‐oxic hot spring source, while sulfur‐oxidizing archaea (Sulfolobales, 57%–82%), and putative sulfur‐oxidizing and heterotrophic bacterial groups dominate oxic downstream environments. The δ¹³C_org (‰ V‐PDB) values for sediment TOC and microbial biomass range from ?9.4‰ at the spring's source decreasing to ?12.6‰ downstream. A reverse effect isotope fractionation of ~3‰ between sediment sulfide (δ³⁴S ~0‰) and dissolved water sulfate (δ³⁴S +3.2‰), and δ¹⁸O values of ~ ?5.3‰ suggest pyrite forms abiogenically from volcanic sulfide, followed by abiogenic and microbial oxidation. These environments represent an unexplored surficial geothermal environment analogous to transient volcanogenic habitats during putative “snowball Earth” scenarios and volcano–ice geothermal environments on Mars.     

Otoliths speak out: why the Pacific halibut in Puget sound are different

Pacific halibut, Hippoglossus stenolepis, is one of the most important commercial groundfish and is managed as a single coast-wide population from Alaska to northern California. Nevertheless, genetic investigations did not show success in detecting the population structure of the species. Here I report stable oxygen and carbon isotope analyses (δ¹⁸O and δ¹³C) in otoliths to discriminate the stock differences from two sample locations between the Washington coast (WC) and the northern Puget Sound (PS), and two sample years in 2007 and 2008. In general the δ¹⁸O values of halibut otoliths from WC ranged from ?0.2 to 1.8‰, higher than the PS samples from ?0.5 to 1.4‰. In contrast, the δ¹³C values from WC ranged from ?3.6 to ?1.0‰, lower than the PS samples from ?3.2 to ?1.2‰. Results from the otolith nuclei (age-0 halibut) and the 8^th (the earliest maturity age for male halibut) and edge otolith rings (the latest location where the fish lived) showed significant differences between halibut samples from PS and WC. In particular, the sample location difference (between PS and WC) in both δ¹³C and δ¹⁸O data was significant and markedly larger than the sample year difference (between 2007 and 2008). These isotopic signatures provide evidence that the PS halibut may belong to a distinct stock that is significantly different from WC halibut.