Utah State University Flutes Solo Recital

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Li/Mg systematics in scleractinian corals: Calibration of the thermometer

We show that the Li/Mg systematics of a large suite of aragonitic coral skeletons, representing a wide range of species inhabiting disparate environments, provides a robust proxy for ambient seawater temperature. The corals encompass both zooxanthellate and azooxanthellate species (Acropora sp., Porites sp., Cladocora caespitosa, Lophelia pertusa, Madrepora oculata and Flabellum impensum) collected from shallow, intermediate, and deep-water habitats, as well as specimens cultured in tanks under temperature-controlled conditions. The Li/Mg ratios observed in corals from these diverse tropical, temperate, and deep-water environments are shown to be highly correlated with temperature, giving an exponential temperature relationship of: Li/Mg (mmol/mol) = 5.41 exp (−0.049 * T) (r² = 0.975, n = 49). Based on the standard error of the Li/Mg versus temperature correlation, we obtain a typical precision of ±0.9 °C for the wide range of species analysed, similar or better than that of other less robust coral temperature proxies such as Sr/Ca ratios.The robustness and species independent character of the Li/Mg temperature proxy is shown to be the result of the normalization of Li to Mg, effectively eliminating the precipitation efficiency component such that temperature remains as the main controller of coral Li/Mg compositions. This is inferred from analysis of corresponding Li/Ca and Mg/Ca ratios with both ratios showing strong microstructure-related co-variations between the fibrous aragonite and centres of calcification, a characteristic that we attribute to varying physiological controls on growth rate. Furthermore, Li/Ca ratios show an offset between more rapidly growing zooxanthellate and azooxanthellate corals, and hence only an approximately inverse relationship to seawater temperature. Mg/Ca ratios show very strong physiological controls on growth rate but no significant dependence with temperature, except possibly for Acropora sp. and Porites sp. A strong positive correlation is nevertheless found between Li/Ca and Mg/Ca ratios at similar temperatures, indicating that both Li and Mg are subject to control by similar growth mechanisms, specifically the mass fraction of aragonite precipitated during calcification, which is shown to be consistent with a Rayleigh-based elemental fractionation model.The highly coherent array defined by Li/Mg versus temperature is thus largely independent of coral calcification mechanisms, with the strong temperature dependence reflecting the greater sensitivity of the KdLi/Ca partition coefficient relative to KdMg/Ca. Accordingly, Li/Mg ratios exhibit a highly coherent exponential correlation with temperature, thereby providing a more robust tool for reconstructing paleo-seawater temperatures

Decadal changes in the mid-depth water mass dynamic of the Northeastern Atlantic margin (Bay of Biscay)

The lithium/magnesium (Li/Mg) molar ratios, radiocarbon measurements (?14C) and Nd-isotopic composition (eNd) of the aragonite skeleton of a branching cold-water coral (CWC) species Madrepora oculata collected alive in the Bay of Biscay at ~691 m water depth were investigated to reconstruct a robust record of the mid-depth water mass dynamics between 1950 and 1990 AD. Temperature estimates based on the skeletons Li/Mg molar ratios reveal small decadal changes of about 1 °C at thermocline depth synchronous to and of similar amplitude as surface temperature anomalies. ?14C measurements shows quasi-decadal oscillations of 15‰ around pre-bomb ?14C average value of -59±6‰ and post-bomb ?14C of -12±6‰, which most likely reflect decadal changes of water mass exchange across the thermocline. The coral eNd values remain in narrow ranges of -11.9 to -10.2, similar to the isotopic composition of East North Atlantic Central Water, but show highest values in the late 1950s, and early 1960s, 1970s, and 1980s. The punctuated changes of the coral Nd-isotopic composition may thus reflect periods of particular enhanced advection of temperate intermediate water (mid-depth Subpolar Gyre/Mediterranean Sea Water). Altogether, our robust multi-proxy record provides new evidence that Northern Hemisphere atmospheric variability (such as, North Atlantic Oscillation and East Atlantic pattern) drives changes not only in the thermocline but also in the mid-depth water-mass advection patterns in the Northeastern Atlantic margin. However, the interannual variability of our record remains to be tested

Dissolved rare earth element and neodymium isotope distributions in the South China Sea: Water mass source versus particle dissolution

Dissolved rare earth elements (REEs) and neodymium isotopes (ϵNd) have been jointly used to evaluate water mass mixing and lithogenic inputs in the ocean. As the largest marginal sea of the West Pacific, the South China Sea (SCS) is an ideal region for reconstructing past hydrological changes. However, its REE and ϵNd distributions and underlying controlling mechanisms remain poorly understood. On the basis of four seawater profiles spread across the SCS, this study presents dissolved REE concentrations and ϵNd data under summer condition to better understand the processes that potentially influence changes in these parameters and their marine cycling. The results show high concentrations of REEs and large variations in ϵNd (−6.7 to −2.8) in surface water, likely caused by the dissolution of riverine and marine particles. Comparison with published data from samples taken during the winter of different years in this and previous studies suggests a possible seasonal variability of middle REE enrichment. The SCS deep water shows a narrow ϵNd range from −4.3 to −3.4, confirming the dominant presence of the North Pacific Deep Water in the deep SCS. The intermediate water in the central SCS is characterized by a more negative ϵNd signal (–4.2 to –3.4) than that found in its counterpart in the West Pacific (–3.5 to –2.8), indicating alterations by deep water through three-dimensional overturning circulation from the northern to southern SCS below ~500 m. The contributions of external sources could be quantitatively estimated for the SCS in terms of Nd. The dissolution of particles from the SCS surrounding rivers (0.26–1.3 tons/yr in summer; 5.6–29 tons/yr in winter) and continental margins (2–12 tons/yr in summer; 23–44 tons/yr in winter) may play an important role in providing additional Nd to the SCS surface water

The Tara Pacific expedition—A pan-ecosystemic approach of the “-omics” complexity of coral reef holobionts across the Pacific Ocean

Coral reefs are the most diverse habitats in the marine realm. Their productivity, structural complexity, and biodiversity critically depend on ecosystem services provided by corals that are threatened because of climate change effects—in particular, ocean warming and acidification. The coral holobiont is composed of the coral animal host, endosymbiotic dinoflagellates, associated viruses, bacteria, and other microeukaryotes. In particular, the mandatory photosymbiosis with microalgae of the family Symbiodiniaceae and its consequences on the evolution, physiology, and stress resilience of the coral holobiont have yet to be fully elucidated. The functioning of the holobiont as a whole is largely unknown, although bacteria and viruses are presumed to play roles in metabolic interactions, immunity, and stress tolerance. In the context of climate change and anthropogenic threats on coral reef ecosystems, the Tara Pacific project aims to provide a baseline of the “-omics” complexity of the coral holobiont and its ecosystem across the Pacific Ocean and for various oceanographically distinct defined areas. Inspired by the previous Tara Oceans expeditions, the Tara Pacific expedition (2016–2018) has applied a pan-ecosystemic approach on coral reefs throughout the Pacific Ocean, drawing an east–west transect from Panama to Papua New Guinea and a south–north transect from Australia to Japan, sampling corals throughout 32 island systems with local replicates. Tara Pacific has developed and applied state-of-the-art technologies in very-high-throughput genetic sequencing and molecular analysis to reveal the entire microbial and chemical diversity as well as functional traits associated with coral holobionts, together with various measures on environmental forcing. This ambitious project aims at revealing a massive amount of novel biodiversity, shedding light on the complex links between genomes, transcriptomes, metabolomes, organisms, and ecosystem functions in coral reefs and providing a reference of the biological state of modern coral reefs in the Anthropocene

Tentative reconstruction of the 1998–2012 hiatus in global temperature warming using the IPSL–CM5A–LR climate model

The period running from 1998 to 2012 has experienced a slower increase in global temperature at the surface of the Earth than the decades before. Several explanations have been proposed, ranging from internal variability of the climate system to a contribution of the natural external forcing. In this study, we use the IPSL-CM5A-LR climate model to test these different hypotheses. We consider historical simulations, including observed external forcing, in which nudging towards observed sea surface temperature has been applied to different regions of the ocean to phase the decadal variability of large-scale modes in the Atlantic and the Pacific to observations. We find that phasing the tropical Pacific is reducing the warming trend detected in historical simulations by a factor of two, but the remaining trend is still twice as large as the observed one. Combining the tropical Pacific phasing and the potential effect of recent eruptions allows us to fully reproduce the observed hiatus. Conversely, nudging the Atlantic does not drive any hiatus in this model

L’insediamento a bifacciali di Guado San Nicola (Monteroduni, Molise, Italia)

La monografia rappresenta un compendio di lavori specialistici sul sito paleolitico di Guado San Nicola a Monteroduni (Molise, Italia), oggetto di ricerche sistematiche ed indagini interdisciplinari inaugurate nell’area a partire dal 2000 dall'Università degli Studi di Ferrara. Il sito, ascrivibile al MIS 10/11, costituisce un tassello importante nell’ambito della ricostruzione del quadro del popolamento umano della penisola italiana e dell’intero bacino del Mediterraneo, alla luce delle considerazioni crono-stratigrafiche, della ricchezza della documentazione e della presenza di elementi innovativi dal punto di vista culturale quali la padronanza del metodo Levallois e l’uso di percussori in palchi di cervo

Strontium isotope evidence for Pre-Islamic cotton cultivation in Arabia

With a view to understanding the dynamics of ancient trade and agrobiodiversity, archaeobotanical remains provide a means of tracing the trajectories of certain agricultural commodities. A prime example is cotton in Arabia, a plant that is non-native but has been found in raw seed and processed textile form at Hegra and Dadan, in the region of al-ʿUlā, north-western Saudi Arabia—sites of critical importance given their role in the trans-Arabian trading routes during Antiquity. Here, we demonstrate that the measurement of strontium isotopes from pre-cleaned archaeological cotton is methodologically sound and is an informative addition to the study of ancient plant/textile provenance, in this case, putting forward evidence for local production of cotton in oasis agrosystems and possible external supply. The presence of locally-grown cotton at these sites from the late 1st c. BCE–mid 6th c. CE is significant as it demonstrates that cotton cultivation in Arabia was a Pre-Islamic socio-technical feat, while imported cotton highlights the dynamism of trade at that time

Interlaboratory study for coral Sr/Ca and other element/Ca ratio measurements

The Sr/Ca ratio of coral aragonite is used to reconstruct past sea surface temperature (SST). Twentyone laboratories took part in an interlaboratory study of coral Sr/Ca measurements. Results show interlaboratory bias can be significant, and in the extreme case could result in a range in SST estimates of 7°C. However, most of the data fall within a narrower range and the Porites coral reference material JCp- 1 is now characterized well enough to have a certified Sr/Ca value of 8.838 mmol/mol with an expanded uncertainty of 0.089 mmol/mol following International Association of Geoanalysts (IAG) guidelines. This uncertainty, at the 95% confidence level, equates to 1.5°C for SST estimates using Porites, so is approaching fitness for purpose. The comparable median within laboratory error is <0.5°C. This difference in uncertainties illustrates the interlaboratory bias component that should be reduced through the use of reference materials like the JCp-1. There are many potential sources contributing to biases in comparative methods but traces of Sr in Ca standards and uncertainties in reference solution composition can account for half of the combined uncertainty. Consensus values that fulfil the requirements to be certified values were also obtained for Mg/Ca in JCp-1 and for Sr/Ca and Mg/Ca ratios in the JCt-1 giant clam reference material. Reference values with variable fitness for purpose have also been obtained for Li/Ca, B/Ca, Ba/Ca, and U/Ca in both reference materials. In future, studies reporting coral element/Ca data should also report the average value obtained for a reference material such as the JCp-1