You eat what you find - Local patterns in vegetation structure control diets of African fungus-growing termites.

Fungus-growing termites and their symbiotic fungi are critically important carbon and nutrient recyclers in arid and semiarid environments of sub-Saharan Africa. A major proportion of plant litter produced in these ecosystems is decomposed within nest chambers of termite mounds, where temperature and humidity are kept optimal for the fungal symbionts. While fungus-growing termites are generally believed to exploit a wide range of different plant substrates, the actual diets of most species remain elusive.

Recurrent transitions to Little Ice Age-like climatic regimes over the Holocene.

Unlabelled: Holocene climate variability is punctuated by episodic climatic events such as the Little Ice Age (LIA) predating the industrial-era warming. Their dating and forcing mechanisms have however remained controversial. Even more crucially, it is uncertain whether earlier events represent climatic regimes similar to the LIA.

New Ag PO comparison material for stable oxygen isotope analysis.

Rationale: A silver phosphate reference material (Ag PO ) for the measurement of stable oxygen isotope compositions is much needed; however, it is not available from the authorities distributing reference materials. This study aims to fill this gap by calibrating a new Ag PO stable isotope comparison material produced by the University of Natural Resources and Life Sciences (BOKU).

Methods: Aliquots of Ag PO were distributed to four laboratories who frequently measure the δ O value in Ag PO ; the University of Natural Resources and Life Sciences (BOKU), the University of Western Australia (UWA), the University of Helsinki (UH), and the Helmholtz Centre for Environmental Research (UFZ).

Sequential extraction of the phosphate and collagen fractions of small bone samples for analysis of multiple isotope systems (δ O , δ C, δ N).

Rationale: Stable isotope analyses are used on precious archeological and paleontological materials despite their destructive nature, because the information gained by these methods on, for example, feeding habits, migration and health of individuals cannot otherwise be obtained. We approached this issue by devising a new sequential extraction scheme aimed at producing multiple (O, C, N) isotope proxies from small amounts of sample.

Methods: The new extraction scheme includes dissolution of the bone in dilute HNO followed by separate treatments of the collagenous and phosphate fractions.

Buried in water, burdened by nature-Resilience carried the Iron Age people through Fimbulvinter.

Levänluhta is a unique archaeological site with the remains of nearly a hundred Iron Age individuals found from a water burial in Ostrobothnia, Finland. The strongest climatic downturn of the Common Era, resembling the great Fimbulvinter in Norse mythology, hit these people during the 6th century AD. This study establishes chronological, dietary, and livelihood synthesis on this population based on stable carbon and nitrogen isotopic and radiocarbon analyses on human remains, supported by multidisciplinary evidence.

Human mitochondrial DNA lineages in Iron-Age Fennoscandia suggest incipient admixture and eastern introduction of farming-related maternal ancestry.

Human ancient DNA studies have revealed high mobility in Europe's past, and have helped to decode the human history on the Eurasian continent. Northeastern Europe, especially north of the Baltic Sea, however, remains less well understood largely due to the lack of preserved human remains. Finland, with a divergent population history from most of Europe, offers a unique perspective to hunter-gatherer way of life, but thus far genetic information on prehistoric human groups in Finland is nearly absent.

Caste-specific nutritional differences define carbon and nitrogen fluxes within symbiotic food webs in African termite mounds.

Fungus-growing termites of the genus Macrotermes cultivate symbiotic fungi (Termitomyces) in their underground nest chambers to degrade plant matter collected from the environment. Although the general mechanism of food processing is relatively well-known, it has remained unclear whether the termites get their nutrition primarily from the fungal mycelium or from plant tissues partly decomposed by the fungus. To elucidate the flows of carbon and nitrogen in the complicated food-chains within the nests of fungus-growing termites, we determined the stable isotope signatures of different materials sampled from four Macrotermes colonies in southern Kenya.

Author Correction: Solar superstorm of AD 774 recorded subannually by Arctic tree rings.

The authors became aware of a mistake in the data displayed in Fig. 1 and Supplementary Table 2 of the original version of the Article. Specifically, the C production values were printed out in the code before the conversion between the omnidirectional fluence and the flux.

Solar superstorm of AD 774 recorded subannually by Arctic tree rings.

Recently, a rapid increase in radiocarbon (C) was observed in Japanese tree rings at AD 774/775. Various explanations for the anomaly have been offered, such as a supernova, a γ-ray burst, a cometary impact, or an exceptionally large Solar Particle Event (SPE). However, evidence of the origin and exact timing of the event remains incomplete.

Arctic moistening provides negative feedbacks to riparian plants.

Arctic moistening will affect the circumpolar forested riparian ecosystems. Upward trends observed for precipitation in high latitudes illustrate that the moistening may be underway to influence the woody biomass production near the inland waters, lakes and streams with effects on carbon pools and fluxes. Although the flooding and waterlogging tolerance of seedlings has been investigated, our understanding of responses in mature trees is still limited.

Volcanic dust veils from sixth century tree-ring isotopes linked to reduced irradiance, primary production and human health.

The large volcanic eruptions of AD 536 and 540 led to climate cooling and contributed to hardships of Late Antiquity societies throughout Eurasia, and triggered a major environmental event in the historical Roman Empire. Our set of stable carbon isotope records from subfossil tree rings demonstrates a strong negative excursion in AD 536 and 541-544. Modern data from these sites show that carbon isotope variations are driven by solar radiation.

Tree height strongly affects estimates of water-use efficiency responses to climate and CO using isotopes.

Various studies report substantial increases in intrinsic water-use efficiency (W ), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO. Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in W as trees grow larger. Here we show, by comparing W across varying tree sizes at one CO level, that ignoring such developmental effects can severely affect inferences of trees' W .

Echoes from the past: a healthy Baltic Sea requires more effort.

Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly.