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cti_cross_region_taxon This repository provides the data and codes used in the manuscript: Guillem Chust, Ernesto Villarino, Matthew McLean, Nova Mieszkowska, Lisandro Benedetti-Cecchi, Fabio Bulleri, Chiara Ravaglioli, Angel Borja, Iñigo Muxika, José A. Fernandes-Salvador, Leire Ibaibarriaga, Ainhize Uriarte, Marta Revilla, Fernando Villate, Arantza Iriarte, Ibon Uriarte, Soultana Zervoudaki, Jacob Carstensen, Paul J. Somerfield, Ana M. Queirós , Andrea J. McEvoy, Arnaud Auber, Manuel Hidalgo, Marta Coll, Joaquim Garrabou, Daniel Gómez-Gras, Cristina Linares, Francisco Ramírez, Núria Margarit, Mario Lepage, Chloé Dambrine, Jérémy Lobry, Myron A. Peck, Paula de la Barra, Anieke van Leeuwen, Gil Rilov, Erez Yeruham, Anik Brind'Amour, and Martin Lindegren. Cross-basin and cross-taxa patterns of marine community tropicalization and deborealization in warming European seas. Nature Communications Please check the github repo cti_cross_region_taxon for updates. Abstract Ocean warming and acidification, decreases in dissolved oxygen concentrations, and changes in primary production are causing an unprecedented global redistribution of marine life. The identification of underlying ecological processes underpinning marine species turnover, particularly the prevalence of tropicalization over deborealization, has been recently debated in the context of ocean warming. Here, we track changes in the mean thermal affinity of marine communities across European seas by calculating the Community Temperature Index for 65 biodiversity time series collected over four decades and containing 1,817 species from different communities (zooplankton, coastal benthos, pelagic and demersal invertebrates and fish). We show most communities and sites have clearly responded to ongoing ocean warming via abundance increases of warm-water species (tropicalization; 54%) and decreases of cold-water species (deborealization; 18%). Tropicalization dominated Atlantic sites compared to semi-enclosed basins such as the Mediterranean and Baltic Seas, probably due to physical barrier constraints to connectivity and species colonization. Semi-enclosed basins appeared to be particularly vulnerable to ocean warming, experiencing the fastest rates of warming and biodiversity loss through deborealization. Keywords: climate change, community temperature index, CTI, ocean connectivity. Acknowledgements This study has been supported by the European Union's Horizon 2020 research and innovation programme under grant agreement No 869300 (FutureMARES project) (G.C., E.V., J.F-S., M.P., M.Lin., C.D., D.G-G., G.R., L.B., C.R., M.C., F.R., G.R., P.B., M.P., M.Lep., J.L., A.B., N.M., J.G., F.B., L.B.C, A.Q., F.V., A.I., and I.U.), and by the Urban Klima 2050 -- LIFE 18 IPC 000001 project, which has been received funding from European Union's LIFE programme (G.C., E.V., L.I., A.B., A.U., and M.R.). Additional financial support was obtained from the Basque Government (PIBA2020-1-0028 & IT1723-22). We thank the NOAA Climate Prediction Center for providing Sea Temperature data through the NCEP Global Ocean Data Assimilation System (GODAS) www.cpc.ncep.noaa.gov/products/GODAS. We also thank Ocean Biodiversity Information System (OBIS) for providing global occurrences of the biological group studied here. Data from the Basque Country were obtained from the Basque Water Agency (URA) monitoring network, through a Convention with AZTI. M.C., J.G., D.G.-G. and F.R. acknowledge the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S). Authors M.H. and M.Lin. are grateful for the support from ICES Working Group on Comparative Ecosystem-based Analyses of Atlantic and Mediterranean marine systems (WGCOMEDA) for this research. This paper is contribution nº xxxx from AZTI, Marine Research, Basque Research and Technology Alliance (BRTA)

The repository contains the version of PISCES that was used to investigate the role played by low latitudes and the Southern Ocean at sustaining export production and PP in the low latitudes. This code is based on version 3.6 of NEMO and the repository only includes routines that have been changed with respect to this version. The code is in Fortran 90.

The effects of antifreeze proteins (AFPs) on the freezing temperatures of water is well studiedand known today. Studies of the affects of antifreeze proteins on glass transition and melting tem-peratures have been conducted on samples containing relatively high concentrations of glyceroland water. In this paper we conduct experiments with antifreeze proteins in water-dominatedglycerol water mixtures to determine how AFPs affect the glass transition and melting temper-atures of these samples. We present theory behind the various interactions that occur betweencomponents of the various mixtures studied and provide mathematical background and proofsto verify our methods. We discuss the hardware and software setups, experimental procedure,preparation of samples and analysis of the gathered data. The experimental results obtained fromthe raw data is presented as well as information on how the data was interpreted. Our analysisof a 23% glycerol water mixture with varying concentrations of teleost fish type III anti-freezeproteins suggest that there is a lowering effect to the glass transition temperature. Uncertainties,arbitrary choices and areas of future research are established for suggestions of the continuedresearch of these phenomena.i

We present a record of melt events obtained from the East Greenland Ice Core Project (EastGRIP) ice core in central northeastern Greenland, covering the largest part of the Holocene. The data were acquired visually using an optical dark-field line scanner. We detect and describe melt layers and lenses, seen as bubble-free layers and lenses, throughout the ice above the bubble–clathrate transition. This transition is located at 1150 m depth in the EastGRIP ice core, corresponding to an age of 9720 years b2k. We define the brittle zone in the EastGRIP ice core as that from 650 to 950 m depth, where we count on average more than three core breaks per meter. We analyze melt layer thicknesses, correct for ice thinning, and account for missing layers due to core breaks. Our record of melt events shows a large, distinct peak around 1014 years b2k (986 CE) and a broad peak around 7000 years b2k, corresponding to the Holocene Climatic Optimum. In total, we can identify approximately 831 mm of melt (corrected for thinning) over the past 10 000 years. We find that the melt event from 986 CE is most likely a large rain event similar to that from 2012 CE, and that these two events are unprecedented throughout the Holocene. We also compare the most recent 2500 years to a tree ring composite and find an overlap between melt events and tree ring anomalies indicating warm summers. Considering the ice dynamics of the EastGRIP site resulting from the flow of the Northeast Greenland Ice Stream (NEGIS), we find that summer temperatures must have been at least 3 ± 0.6 ∘C warmer during the Early Holocene compared to today.

This study presents simulations of Greenland surface melt for the Eemian interglacial period (∼130 000 to 115 000 years ago) derived from regional climate simulations with a coupled surface energy balance model. Surface melt is of high relevance due to its potential effect on ice core observations, e.g., lowering the preserved total air content (TAC) used to infer past surface elevation. An investigation of surface melt is particularly interesting for warm periods with high surface melt, such as the Eemian interglacial period. Furthermore, Eemian ice is the deepest and most compressed ice preserved on Greenland, resulting in our inability to identify melt layers visually. Therefore, simulating Eemian melt rates and associated melt layers is beneficial to improve the reconstruction of past surface elevation. Estimated TAC, based on simulated melt during the Eemian, could explain the lower TAC observations. The simulations show Eemian surface melt at all deep Greenland ice core locations and an average of up to ∼30 melt days per year at Dye-3, corresponding to more than 600 mm water equivalent (w.e.) of annual melt. For higher ice sheet locations, between 60 and 150 mmw.e.yr-1 on average are simulated. At the summit of Greenland, this yields a refreezing ratio of more than 25 % of the annual accumulation. As a consequence, high melt rates during warm periods should be considered when interpreting Greenland TAC fluctuations as surface elevation changes. In addition to estimating the influence of melt on past TAC in ice cores, the simulated surface melt could potentially be used to identify coring locations where Greenland ice is best preserved.

Although it has been demonstrated that the speed and magnitude of the recent Arctic sea ice decline is unprecedented for the past 1450 years, few records are available to provide a paleoclimate context for Arctic sea ice extent. Bromine enrichment in ice cores has been suggested to indicate the extent of newly formed sea ice areas. Despite the similarities among sea ice indicators and ice core bromine enrichment records, uncertainties still exist regarding the quantitative linkages between bromine reactive chemistry and the first-year sea ice surfaces. Here we present a 120 000-year record of bromine enrichment from the RECAP (REnland ice CAP) ice core, coastal east Greenland, and interpret it as a record of first-year sea ice. We compare it to existing sea ice records from marine cores and tentatively reconstruct past sea ice conditions in the North Atlantic as far north as the Fram Strait (50–85∘ N). Our interpretation implies that during the last deglaciation, the transition from multi-year to first-year sea ice started at ∼17.5 ka, synchronously with sea ice reductions observed in the eastern Nordic Seas and with the increase in North Atlantic ocean temperature. First-year sea ice reached its maximum at 12.4–11.8 ka during the Younger Dryas, after which open-water conditions started to dominate, consistent with sea ice records from the eastern Nordic Seas and the North Icelandic shelf. Our results show that over the last 120 000 years, multi-year sea ice extent was greatest during Marine Isotope Stage (MIS) 2 and possibly during MIS 4, with more extended first-year sea ice during MIS 3 and MIS 5. Sea ice extent during the Holocene (MIS 1) has been less than at any time in the last 120 000 years.

This study examines the stable water isotope signal (δ18O) of three ice cores drilled on the Renland peninsula (east Greenland coast). While ice core δ18O measurements qualitatively are a measure of the local temperature history, the δ18O variability in precipitation actually reflects the integrated hydrological activity that the deposited ice experienced from the evaporation source to the condensation site. Thus, as Renland is located next to fluctuating sea ice cover, the transfer function used to infer past temperatures from the δ18O variability is potentially influenced by variations in the local moisture conditions. The objective of this study is therefore to evaluate the δ18O variability of ice cores drilled on Renland and examine the amount of the signal that can be attributed to regional temperature variations. In the analysis, three ice cores are utilized to create stacked summer, winter and annually averaged δ18O signals (1801–2014 CE). The imprint of temperature on δ18O is first examined by correlating the δ18O stacks with instrumental temperature records from east Greenland (1895–2014 CE) and Iceland (1830–2014 CE) and with the regional climate model HIRHAM5 (1980–2014 CE). The results show that the δ18O variability correlates with regional temperatures on both a seasonal and an annual scale between 1910 and 2014, while δ18O is uncorrelated with Iceland temperatures between 1830 and 1909. Our analysis indicates that the unstable regional δ18O–temperature correlation does not result from changes in weather patterns through strengthening and weakening of the North Atlantic Oscillation. Instead, the results imply that the varying δ18O–temperature relation is connected with the volume flux of sea ice exported through Fram Strait (and south along the coast of east Greenland). Notably, the δ18O variability only reflects the variations in regional temperature when the temperature anomaly is positive and the sea ice export anomaly is negative. It is hypothesized that this could be caused by a larger sea ice volume flux during cold years which suppresses the Iceland temperature signature in the Renland δ18O signal. However, more isotope-enabled modeling studies with emphasis on coastal ice caps are needed in order to quantify the mechanisms behind this observation. As the amount of Renland δ18O variability that reflects regional temperature varies with time, the results have implications for studies performing regression-based δ18O–temperature reconstructions based on ice cores drilled in the vicinity of a fluctuating sea ice cover.