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AbstractSea turtles (Cheloniidae) are extremely rare in the Northern European archaeological record; however, sporadic finds have occurred. Here we used bioarchaeological tools to investigate two archaeological sea turtle specimens found in the Netherlands. The aim of this study is to investigate whether these represented stranded or imported specimens. The first specimen was excavated in Schagen, a city in the north-west of the country, and has an approximate age predating AD 1500. The second specimen was excavated in Leeuwarden, Friesland, from an early-modern deposit spanning AD 1650–1850. We employed a combination of zooarchaeology by mass spectrometry (ZooMS) and δ13C and δ15N stable isotope analysis. ZooMS analysis identified the Schagen and Leeuwarden specimens as a loggerhead turtle (Caretta caretta) and a green turtle (Chelonia mydas), respectively. Isotope provenancing based on modern samples from different global regions indicated the Leeuwarden specimen was most likely imported during a period when sea turtle soup, a high-status meal, was at the height of popularity. This approach demonstrates how bioarchaeological methods, combined with ecological insights, can shed light into the history of sea turtle occurrences and trade. [ABSTRACT FROM AUTHOR]

Marine historical ecology provides a means to establish baselines to inform current fisheries management. Groupers (Epinephelidae) are key species for fisheries in the Mediterranean, which have been heavily overfished. Species abundance and distribution prior to the 20th century in the Mediterranean remains poorly known. To reconstruct the past biogeography of Mediterranean groupers, we investigated whether Zooarchaeology by Mass Spectrometry (ZooMS) can be used for identifying intra‐genus grouper bones to species level. We discovered 22 novel, species‐specific ZooMS biomarkers for groupers. Applying these biomarkers to Kinet Höyük, a Mediterranean archaeological site, demonstrated 4000 years of regional Epinephelus aeneus dominance and resiliency through millennia of fishing pressures, habitat degradation and climatic changes. Combining ZooMS identifications with catch size reconstructions revealed the Epinephelus aeneus capacity for growing 30 cm larger than hitherto documented, revising the maximum Total Length from 120 to 150 cm. Our results provide ecological baselines for a key Mediterranean fishery which could be leveraged to define and assess conservation targets. [ABSTRACT FROM AUTHOR]

“Protect and restore ecosystems and biodiversity” is the second official aim of the current UN Ocean Decade (2021 to 2030) calling for the identification and protection of critical marine habitats. However, data to inform policy are often lacking altogether or confined to recent times, preventing the establishment of long-term baselines. The unique insights gained from combining bioarchaeology (palaeoproteomics, stable isotope analysis) with contemporary data (from satellite tracking) identified habitats which sea turtles have been using in the Eastern Mediterranean over five millennia. Specifically, our analysis of archaeological green turtle (Chelonia mydas) bones revealed that they likely foraged on the same North African seagrass meadows as their modern-day counterparts. Here, millennia-long foraging habitat fidelity has been directly demonstrated, highlighting the significance (and long-term dividends) of protecting these critical coastal habitats that are especially vulnerable to global warming. We highlight the potential for historical ecology to inform policy in safeguarding critical marine habitats. [ABSTRACT FROM AUTHOR]

Our goal was to understand the mechanisms behind the impact of nutrient enrichment at intermediate distances from aquaculture on the interactions of a subtidal macroalgae community with its main grazer, the sea urchin Paracentrotus lividus. We assessed the diversity and cover of the macroalgal community, the abundance and biometrics of the sea urchins, the carbon and nitrogen elemental and isotopic compositions, and their metabolome in two stations, at an intermediate distance (station A) and away (station B) from a fish cage facility in the Aegean Sea (Greece), during the warm and cold seasons. The nutrient input at station A favored a shift to a macroalgal assemblage dominated by turf-forming species, depleted of native-erected species and with a higher abundance of invasive algae. A stable isotope analysis showed fish-farm-associated nitrogen enrichment of the macroalgae and trophic transfer to P. lividus. A decrease in metabolites related to grazing, reproduction, and energy reserves was found in P. lividus at station A. Furthermore, the metabolomic analysis was able to pinpoint stress in P. lividus at an intermediate distance from aquaculture. The chosen combination of traditional ecology with omics technology could be used to uncover not only the sublethal effects of nutrient loading but also the pathways for species interactions. [ABSTRACT FROM AUTHOR]

• Increased stress and reduced growth with proximity to fish-cages. • Metabolomics is successful in identifying Cymodocea nodosa nutrient stress. • Metabolomics and traditional indicators provide a holistic overview of seagrass status. • Monitoring efforts would benefit from metabolomics as early warning indicator. Seasonal variation of structural, physiological and growth indicators and the metabolome of the seagrass Cymodocea nodosa , as well as biogeochemical conditions of underlying sediment were studied in two meadows growing at increasing distance downstream from a fish farm in the Aegean Sea in order to assess seagrass performance under stress. Horizontal rhizome production decreased significantly with proximity to the fish farm (0.67 and 1.57 g DW m−2 d−1 close and far from the fish-farm, respectively). This coincided with observed effects on ecophyiological indicators, such as rhizome nitrogen, leaf carbon and leaf δ13C, which were elevated with proximity to the fish-farm. Seasonality was shown by some indicators being elevated in either in the warm (C of all tissues and leaf δ34S) or the cold period (N of all tissues). Growth promoting metabolites (sucrose, fructose, myo-inositol, heptacosane, tetracosane, stigmasterol, catechin and alpha-tocopherol) were lower close to the zone, whereas metabolites involved with stress-response (alanine, serine, proline, putrescine, ornithine, 3,4-dihydroxybenzoic acid and cinnamic acid) were higher. We found that growth-promoting metabolites were positively correlated with horizontal rhizome production, whereas the metabolites related to stress were negatively correlated. Metabolomic fingerprinting of seagrass provides opportunities for early detection of environmental degradation in marine ecological studies. [ABSTRACT FROM AUTHOR]