ALBERT

Description: Proclaimed in 2017 by the United Nations General Assembly, the United Nations Decade of Ocean Science for Sustainable Development – the Ocean Decade – is a framework to identify, generate and use critical ocean knowledge that is needed to manage the ocean sustainably, and achieve global aspirations for climate, biodiversity, and human well-being. Through its vision of ‘The science we need for the ocean we want’, the Ocean Decade provides an inclusive, equitable and global framework for diverse actors to co-design and co-deliver transformative ocean science to meet ten Ocean Decade Challenges. Through a collaborative, solutions-oriented approach, the Ocean Decade will contribute essential knowledge to global, regional, and national policy frameworks, including the 2030 Agenda and the Sustainable Development Goals.1 The Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO) leads the coordination of the Ocean Decade, in collaboration with numerous partners from the United Nations system, governments, philanthropy, industry, civil society and the scientific community. 2021 was the first year of implementation of the Ocean Decade – a watershed moment in ocean science globally – and the achievements since the launch have been significant. Although challenges remain, particularly in relation to investment in ocean science, a robust foundation is now in place for the next nine years of transformative ocean science.

Description: OpenASFA input

Description: Published

Description: Refereed

Description: GenOcean instils a feeling of unity - it's not them and us - we are all in this together. Connecting with the audience, gaining their trust, and allowing them to seamlessly collaborate is essential. But to connect, we have to be on the same wavelength. This campaign identity guide serves as the starting point to create a unified, inspiring and determined campaign that aims to inspire everyday actions to restore and protect the ocean. The following pages contain inspiration, guidelines, and handy tips to communicate our values, realize our vision, and reinforce the GenOcean campaign. Thank you for helping achieve the GenOcean mission to restore and protect the ocean. Welcome to GenOcean.

Description: Government of Japan

Description: From the People of Japan

Description: University of Education, Culture, Sports, Science and Technology, Japan

Description: OPENASFA INPUT For bibliographic purposes, this publication should be cited as follows: IOC-UNESCO. GenOcean Campaign Identity. Paris. 2022. 72 pp. (The Ocean Decade Series, 33).

Description: Published

Description: Not Known

Description: Rationale for this report The Ocean Decade and the Ocean Panel have been developed in full recognition of their mutual importance and influence. The ultimate goal of this report is to analyse tangible ways in which the linkages between the Ocean Decade, with its vision of the ‘science we need for the ocean we want’, and the framework identified by the Ocean Panel, with its aims of safeguarding the long-term health and resilience of the ocean, can be optimized. Ocean science encompasses natural and social science disciplines; the technology and infrastructure that supports ocean science; the application of ocean science for societal benefit, including knowledge transfer and applications in regions that are lacking science capacity; and the science-policy and science-innovation interfaces. It considers the land-sea, ocean-atmosphere and ocean-cryosphere interactions. Ocean science recognizes, respects and embraces local and indigenous knowledge. Source: Ocean Decade Implementation Plan. See note 4. This report has been prepared by the Secretariat of the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO) in its role of coordinating agency of the implementation of the Ocean Decade. It represents the first attempt to explicitly analyse and document the synergies that exist and which could be developed in the future. It is a first step in a process to develop a lean, reliable guiding framework for ocean action, where existing initiatives mutually reinforce each other, thus augmenting their cumulative impact. The need to urgently build back better from the COVID-19 pandemic is recognized by governments and partners worldwide. More than ever before, the current crisis has highlighted the importance of science and knowledge for decision-making and policy. Analysing the synergies between the Ocean Decade and the Ocean Panel – one built around action-oriented knowledge creation and the other explicitly oriented towards policy – naturally responds to this emerging demand for science that is relevant to society. This report builds on the declaration of the 14 world leaders on the Ocean Panel who commit to leveraging the Ocean Decade and the body of knowledge commissioned by the Ocean Panel to build collective understanding and knowledge of ocean sustainability, ecosystem services and functions, and to ensuring that science underpins decision-making for building a sustainable ocean economy.6 It is intended for a broad spectrum of stakeholders, including governments, policymakers, scientists, industry, funding agencies, NGOs and civil society, to raise awareness about the intersections between the action framework of the Ocean Decade and the recommendations of the Ocean Panel. A sustainable ocean economy brings diverse stakeholders together to achieve common goals – the three Ps of effective protection, sustainable production and equitable prosperity. In the sustainable ocean economy paradigm, groups work together by adopting integrated and balanced management of the ocean in which each of the three Ps contributes to the other. The result is a triple win for nature, people and economy and a world where prosperity is greater and more equitably distributed than it is today. Source: Adapted from Stuchtey et al., 2020. See note 10. It speaks both to governments and partners who have committed to the Ocean Panel’s vision of protection, production and prosperity – as well as aiming to incite and catalyse action and commitments from new governments and partners. It deliberately focuses on palpable recommendations that will allow all concerned actors – including members of the Ocean Panel, Ocean Decade partners and members of the future Ocean Panel Action Coalitions – to streamline efforts and carry out effective, collective actions that will lead to sound ocean management, a sustainable ocean economy, and ultimately to achieve the ocean we want – and need – by 2030. For bibliographic purposes, this publication should be cited as follows: IOC-UNESCO. 2021. Ocean Knowledge for a Sustainable Ocean Economy: Synergies between the Ocean Decade and the Outcomes of the Ocean Panel. Paris, UNESCO. (The Ocean Decade Series, 17).

Description: Portuguese Republic

Description: OPENASFA INPUT

Description: Published

Description: Not Known

Description: In 2016, the first World Ocean Assessment of the United Nations stated that humankind was running out of time to start managing the ocean sustainably. This alarming conclusion poses a question to our civilization: is there a way to reverse the decline in ocean health while continuing to rely on the ocean for our ever-increasing needs, particularly under a changing climate? The proclamation by the United Nations General Assembly in December 2017 of the UN Decade of Ocean Science for Sustainable Development, 2021–2030 (hereafter, the ‘Ocean Decade’) is based on the informed conviction of UN Member States that indeed, this opportunity still exists, and that, furthermore, ocean science needs to play a central role in this process. Ocean science is broad: it encompasses natural and social science disciplines, local and indigenous knowledge; it includes the science-policy and science-innovation interfaces, as well as technology and infrastructure. At the beginning of the third millennium, ocean science is largely competent for diagnosing problems. However, its ability to offer solutions of direct relevance to sustainable development requires a massive upgrade. This need is particularly urgent against the current backdrop of the global COVID-19 pandemic and accelerating climate change. The pandemic has, once again, highlighted the importance of science and knowledge for decision-making and policy. As the world adjusts to a new normal, the ocean will need to play a central role in post-pandemic recovery efforts. However, for this to occur, there needs to be a nothing short of a revolution in ocean science. The Ocean Decade will create a paradigm shift in the generation of qualitative and quantitative ocean knowledge – including from currently data-poor regions, such as the deep ocean, coastal areas where much of the human interaction with the ocean is concentrated, and the polar regions – to inform the development of solutions that contribute to the 2030 Agenda for Sustainable Development. The Ocean Decade aims to catalyse the human behaviour change required for the successful implementation of these solutions. Guided by the United Nations Convention on the Law of the Sea (UNCLOS), the Ocean Decade will generate the data, information and knowledge needed for more robust science-informed policies and stronger science-policy interfaces at global, regional, national and even local levels, leading to improved integrated ocean management and development of a sustainable ocean economy. The Ocean Decade will support numerous UN entities to fulfil their ocean-related mandates. In our information-centred, internet-linked society, the Ocean Decade will support ocean data, information and knowledge systems to evolve into a much higher level of readiness, accessibility, and interoperability. The scale of such efforts will need to be exponentially greater than anything seen to date. An equally transformational part of the Ocean Decade is about humanity and our relationship with the ocean. Understanding of the value of the ocean can be nurtured through ocean literacy efforts among diverse stakeholder groups. Holders of indigenous and local knowledge will work as essential partners of the Ocean Decade and will contribute to highlighting the multitude of cultural values of the ocean. Equity, inclusiveness, respect, fairness and scientific integrity are core principles of the Ocean Decade. The Ocean Decade will systematically identify and dismantle barriers to achieving gender, geographic and generational balance so that no one is left behind. Everyone should be able to benefit from ocean science, including Small Island Developing States, Least Developed Countries and Landlocked Developing Countries. Designing and delivering ocean science that focuses on user needs and adopts relevant mechanisms for uptake will be a key metamorphosis to be achieved between 2021 and 2030. Its scale will be unprecedented. Multiple stakeholders are expected to engage and start collaborating outside their traditional communities. Knowledge generators and users will engage in an iterative process of co-design and co-delivery of ocean science. This will create new groupings of actors from natural, social science and humanity disciplines, business and industry, governments, UN entities, intergovernmental organizations (IGOs), NGOs and civil society, educators, early career ocean professionals, ocean sports and recreation organizations, arts and cultural communities, and indigenous and local knowledge holders. Partnerships and active communication will be at the heart of the Ocean Decade. This Decade is not the first to take on the challenge of ocean science. In 1971–1980, earlier generations embarked on the International Decade of Ocean Exploration. As part of that Decade, groundbreaking collaborative research projects occurred. Many of which, such as the World Ocean Circulation Experiment, permanently changed the face of ocean exploration. However, one crucial difference remains between the two Decades: in the 1970s, the aim was to generate the ‘science we want’. In today’s world, we no longer have that luxury, and the current Decade is resolutely focused on the ‘science we need’. The Implementation Plan for such a major undertaking as the Ocean Decade cannot be, and is not, prescriptive. Rather, it provides a framework for transformational action that will build on existing achievements and deliver action across geographies, sectors, disciplines and generations. I hope you, as a reader and an Ocean Decade stakeholder, will share the overall strategic vision and approach of the Ocean Decade as described in the Implementation Plan. With your engagement and your support, the impact of the Ocean Decade will be much bigger than the sum of its parts and together we will be able to create the science we need for the ocean we want.

Description: OPENASFA INPUT he document should be cited as follows: UNESCO-IOC (2021). The United Nations Decade of Ocean Science for Sustainable Development (2021-2030) Implementation Plan. UNESCO, Paris (IOC Ocean Decade Series, 20.).

Description: Published

Description: Not Known

Description: On 5 December 2017, the United Nations (UN) declared that a Decade of Ocean Science for Sustainable Development (‘Ocean Decade’) would be held from 2021 to 2030. The Ocean Decade provides a common framework to ensure that ocean science can underpin the achievement of the 17 Sustainable Development Goals (SDGs) and complementary global and regional policy frameworks including the United Nations Framework Convention on Climate Change. The Ocean Decade provides a ‘once-in- a-lifetime’ opportunity to create a new foundation across the science-policy interface to strengthen the management of the ocean and coasts for the benefit of humanity and to mitigate the impacts of climate change. The Ocean Decade Implementation Plan outlines ten Decade Challenges, representing the most immediate and pressing needs of the Decade, which will guide stakeholders as they come together to co-design and co-deliver a wide range of Decade Actions that will be implemented the ocean-climate nexus is embodied in Challenge No. 5 and is reflected in a number of the other Challenges over the next ten years. The Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO) has been mandated to coordinate implementation of the Ocean Decade. The Ocean Decade will provide the data, knowledge and capacity to address science and knowledge gaps needed to make informed policy decisions. The United Nations (UN) General Assembly clearly recognizes the societal benefits of a healthy ocean and the need to work across UN entities to achieve this goal. Working in coordination with the UN Framework Convention on Climate Change (UNFCCC), the Ocean Decade will contribute to addressing these societal challenges for example by providing the sound science needed to reflect ocean considerations in Nationally Determined Contributions (NDCs) of the Paris Agreement on Climate Change. In the Ocean and Climate Change Dialogue1, the UNFCCC reaffirmed that science must be strengthened and central to this process. The complementary structure of the Ocean Decade Action Framework to the goals of COP26 will allow for meaningful contributions in achieving successful outcomes.

Description: MEXT

Description: From the People of Japan

Description: OPENASFA INPUT UNESCO-IOC.2021. The Ocean Decade at COP26 of the United Nations Framework Convention on Climate Change. Paris, UNESCO. (The Ocean Decade Series, 31) - (IOC/2021/ODS/31)

Description: Published

Description: Not Known

Description: The Implementation Plan of the UN Decade of Ocean Science for Sustainable Development (the Ocean Decade) calls for ‘transformative science’ and a ‘revolution in how that science is produced, used and disseminated’. The solutions-oriented nature of the Ocean Decade creates the conditions for this revolution because it provides a convening framework to foster the partnerships and develop the scientific knowledge needed to catalyse transformative ocean science solutions for sustainable development, connecting people and our ocean. While there is widespread enthusiasm to engage in this collaborative venture, there is a need to build capacity and common understanding in how to create co-designed solutions that could bring about the desired transformation in ocean management. This discussion note ‘Co-designing the Science We Need for the Ocean We Want: Guidance and Recommendations for Collaborative Approaches to Designing & Implementing Decade Actions’ aims to address this in a holistic manner. It was inspired by discussions held during a series of global and regional webinars in late 2020 that brought together 2,100 individuals from around the world to bring to life the notion of collaborative, co-designed science and identify the key obstacles, challenges and opportunities. The note offers a solid starting point for stakeholders on the: what, why and how they can join efforts to co-design salient, credible and legitimate ocean knowledge solutions which deliver on the Ocean Decade’s vision of ‘the science we need for the ocean we want’.

Description: Government of Sweden

Description: International Science Council

Description: OPENASFA INPUT For bibliographic purposes, this publication should be cited as follows: IOC-UNESCO. 2021. Co-designing the Science We Need for the Ocean We Want: Guidance and Recommendations for Collaborative Approaches to Designing & Implementing Decade Actions. Paris, UNESCO. (The Ocean Decade Series, 29).

Description: Published

Description: Not Known

Description: The DCU provided an overview of the Ocean Decade history, rationale and implementation progress as well as key perspectives and challenges for the future.. The DCU reported continued strong enthusiasm to be part of the Decade – “exciting” “innovative” “transformative”, although it noted a growing desire for collective efforts to set strategic ambitions and not remain entirely ‘bottom-up’ which is a significant (but natural) change in opinion. The DCU also recognized the growing desire to understand how the Ocean Decade will contribute to sustainable ocean management and sustainable ocean economic development. The DCU noted increased engagement, and growing private sector and national engagement but reinforced to the Board that it is important to emphasize the Decade as a regional and global collaborative space so as to avoid a purely national focus resulting in 150 national Ocean Decades. Challenges and opportunities for the Ocean Decade’s immediate future were presented. The challenges identified were growing requests and first signs of impatience vis-a-vis the role of Ocean Decade in resource mobilisation; weak leadership roles of partners from Least Developed Countries (LDCs) and Small Island Developing States (SIDS); limited engagement with key funding partners including multilateral development banks (MDBs) and international financing instruments; pressure growing to systematically measure and report on progress of Ocean Decade; and a systematic approach to capacity development and exchange is emerging but needs more attention and targeted support. One question some Board members raised was ‘what legacy does the Ocean Decade want to leave?’ positing that it may be useful to identify if the underlying goal is to increase investment, produce science, place a mark on the SDGs and contribute to the post-2030 process; or all of these. The recommendation being that this will solidify the tangible benefit of being affiliated with the Ocean Decade and give direction to the energy that has been generated. Other members emphasised the importance of engaging women and youth in the Ocean Decade and heightening the impact of regional action in which many stakeholders are already engaged. The Board showed support for and willingness to engage further with private sector enterprises, international financing institutions and instruments, and philanthropy to unlock investment in ocean science. An acknowledgment was made that SIDS and LDC mobilisation will require a strengthening of the “business case” of the Ocean Decade and the availability of dedicated resources.

Description: OPENASFA INPUT

Description: Published

Description: Not Known

Description: Esta publicación constituye un compendio de mapas, documentos cartográficos y textos de apoyo, preparado especialmente para brindar información sobre la historia, el paisaje, la población, las actividades económicas y algunos aspectos de gobernabilidad del territorio del golfo de Urabá. La geografía, desde la cartografía, ofrece la ventaja de representar espacialmente distintos tipos de información, permitiendo el montaje de mapas a variadas escalas para una mejor ilustración de los aspectos tanto físicos como biológicos y antrópicos del golfo de Urabá.

Description: Published

Description: Refereed

Description: La finalidad de este documento es describir en forma pormenorizada el diseño, funcionamiento y productos de la REDCAM, suministrando una aproximación General acerca de la naturaleza y pertenencia del sistema, para que los usuarios comprendan su funcionamiento a nivel técnico y operativo.

Description: Published

Description: Refereed

Description: El presente libro representa el primer esfuerzo por integrar y sintetizar la información más relevante sobre los pastos y las praderas marinas en el Caribe colombiano, su distribución geográfica, sus características estructurales, su fauna, flora, importancia ecológica, recursos y amenazas. En él se ha pretendido plasmar de forma integral y sintética los resultados de las investigaciones sobre este ecosistema en los últimos años, pero particularmente los derivados del estudio general de línea base titulado “Distribución, estructura y clasificación de las praderas de fanerógamas marinas en el Caribe colombiano”, desarrollado recientemente (2001 – 2002). También se han incorporado en este libro resultados relevantes de trabajos, la mayoría inéditos, realizados por distintos investigadores que tratan aspectos particulares complementarios sobre las praderas de pastos o su comunidad biológica acompañante a escala más local.

Description: Published

Description: Refereed

Description: El presente libro pretende dar a conocer y entender las características naturales del bosque de manglar, los impactos derivados de diversas actividades antrópicas, el uso y aprovechamiento de los recursos por parte de las comunidades locales, así como las acciones interinstitucionales realizadas en torno a la rehabilitación de la ecorregión Ciénaga grande de Santa Marta.

Description: Published

Description: Refereed

Description: El propósito de este libro es presentar, en forma sintética y analítica, lo resultados de los primeros 7 años del monitoreo ambiental que se ha llevado a cabo en la Bahía de Chengue. Para ello se describen y los patrones de comportamiento anual y observados en cada variable estudiada, y se comparan entre años, entre ecosistemas y con otra mediciones realizadas en el área de Santa Marta, en el Caribe y en otras regiones del mundo.

Description: Published

Description: Refereed

Description: Im Spätsommer 1996 wurde in der oberoligozänen Fossillagerstätte Enspel im nordwestlichen Westerwald vom Geologischen Landesamt Rheinland-Pfalz, gemeinsam mit dem Landesamt für Denkmalpflege Rheinland-Pfalz, eine Forschungsbohrung niedergebracht. Die Bohrung erreichte eine Teufe von 256,3 m. Es wurden 2,6 m Basalt, etwa 137 m lakustrine Sedimente und 90 m Vulkaniklastika erbohrt. An deren Basis folgen fragmentierte devonische Sedimentgesteine, die bis zu einer Mächtigkeit von 24,3 m erbohrt wurden. Die Abfolge repräsentiert die Füllung eines komplexen, maarähnlichen Beckens. Der Bohrkern wird in einem interdisziplinären Projekt von verschiedenen Arbeitsgruppen untersucht, um Bau und Genese des ehemaligen Enspelsees zu erforschen.

Description: Abstract: In late summer 1996 the Geological Survey of Rheinland-Pfalz and the Landesamt für Denkmalpflege Rheinland-Pfalz sank a research core, in the Upper Oligocene Fossillagerstätte Enspel, Northwest-Westerwald-area. The drilling reached a depth of 256.3 m. 2.6 m of basalt, 137 m of lakustrine sediments, 90 m of pyroclastic rocks and 24.3 m of fragmented Devonian sediments were found. This section documents the filling of a complex maarlike basin. The cores are examined in an interdisciplinary research project concerning the genesis and structure of the Enspel lake system.

Description: research

Description: Numerous newly-identified traces of active faults in the Himalayan foothill zone along the HFF around Chandigarh, in Pinjore Dun, along the piedmont zone of the Lower Siwalik hill front and within the Lower Tertiary hill range reveal the pattern of thrust and strike-slip faulting, striking parallel to the principal structural trend (NNW-SSE) of the orogenic belt. The active Chandigarh Fault, Pinjore Garden Fault and Barsar thrust have vertically dislocated, warped and backtilted fluvial and alluvial-fan surfaces made up of Late Pleistocene-Holocene sediments. West- and southwest-facing fault scarplets with heights ranging from 12 to 50 m along these faults suggest continued tectonic movement through Late Pleistocene to recent times. Gentle warping and backtilting of the terraces on the hanging wall sides of the faults indicate fault-bend folding. These active faults are the manifestation of north-dipping imbricated thrust faults branching out from the major fault systems like the Main Boundary Fault (MBF) and Himalayan Frontal Fault (HFF), probably merging down northward into a décollement. The Taksal Fault, striking NNW-SSE, shows prominent right-lateral movement marked by lateral offset of streams and younger Quaternary terraces and occupies a narrow deep linear valley along the fault trace. Right stepping along this fault has resulted in formation of a small pull-apart basin. Fault scarplets facing ENE and WSW are the manifestation of dip-slip movement. This fault is an example of slip-partitioning between the strike-slip and thrust faults, suggesting ongoing oblique convergence of the Indian plate and northward migration of a tectonic sliver. Slip rate along the Taksal Fault has been calculated as 2.8 mm/yr. Preliminary trench investigation at the base of the Chandigarh Fault Scarp has revealed total displacement of 3.5 m along a low angle thrust fault with variable dip of 20° to 46° due northeast, possibly the result of one large magnitude (Mw 7) prehistoric earthquake. Taking into consideration the height of the Pinjore surface (20 to 25 m), tentative age (8.9 ± 1.9 ka), displacement during one event and average angle of fault dip (25°) gives slip rate of about 6.3 ± 2 mm/yr, a rate of horizontal shortening of 5.8 ± 1.8 mm/yr and recurrence of faulting of 555 ± 118 years along the Himalayan Frontal Fault.

Description: Published

Description: JCR Journal

Description: open

Description: Invasive alien species represent one of the main environmental threats to native biodiversity and can also strongly alter the biogeochemical cycles within an ecosystem. This study aims to define the distribution of the invasive alien species Cotula cor-onopifolia L. within the protected wetland "Variconi" (Campania region, southern Italy) and evaluate the potential role of water geochemical features as interpretation tools for pattern distribution. The presence of C. coronopifolia was assessed in the field, and a distribution map was drawn; concomitantly thirty-nine water samples were collected from groundwater and surface water bodies for chemical analyses. The results showed that C. coronopifolia preferentially colonized the sector of the wetland characterized by high halinity, while it is totally absent in retrodunal and sandy coastal area with very high halinity. The cartography presented can be used as a tool to help target future management interventions. Through our multidisciplinary approach, new evidence has been provided on the ecology of this invasive alien plant that occupies several wetlands worldwide. The replicability of this method may be useful to assess the level of invasion of an alien species but also to predict its evolution as a function of environmental parameters.

Description: Published

Description: 1653–1668

Description: JCR Journal

Description: ABSTRACTWe present and discuss the results of a geomorphological and geological study aimed at reconstructing the Plio-Quaternary evolution of the NW Sicily coastal belt , a low strain rate region in the central Mediterranean Sea.We performed morphometric and field analysis of Quaternary marine terraces extracting more than 300 shoreline location points subdivided into six orders. The obtained dataset was validate by investigating the morphological changes along topographic profiles and comparing the extracted locations and elevations with the stratigraphic boundaries in the Plio-Quaternary units.We distinguished two contiguous coastal sectors characterized by different paleo-shoreline elevations and Plio-Quaternary evolution, whose estimated uplift rates fit well with the well-known, regional eastward uplift rate increase along the Northern Sicilian continental margin.Obtained results, summarized in a geomorphological map and a morpho-evolutionary model, provide new valuable data to characterize the active deformation processes and the seismotectonic setting in this critical sector of the Africa-Europe plate boundary.

Description: Published

Description: 2159889

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: In this paper we employ a combination of gravity and hydrologic data to constrain a hydraulic model of the Škocjan Caves, an allogenic dominated karstic system in Slovenia. The gravity time-series recorded by a spring-based gravimeter, are carefully analyzed to remove tidal and non-tidal effects and unveil the local hydrologic contribution, which is influenced by the temporary accumulation of water in the cave system during the flood events of the Reka river. We make use of a combined analysis of three large flood events with peak river discharge of about 200, 230 and 300 m3/s, that caused significant water level and gravity variations sensed by the pressure transducer and by the gravimeter. By the integration of hydraulic modelling we study the different coupled gravimetric-hydrologic responses to these flood events: we show that, depending on the peak discharge and duration of the event, different flow conditions are present in the cave system. In addition to the information provided by the pressure transducer, the gravimeter is sensitive to the flow dynamics in a different sector of the cave due to the choice of its location; this configuration helps to better constrain the hydraulic model. Moreover, we find that the autogenic recharge by percolating water can significantly affect the gravity time-series and must be considered in related models. By inclusion of both the hydraulic model outcomes and of the modelling of the autogenic recharge, we are able to better explain the gravity transients during the two smaller magnitude events. In particular, during such events the autogenic contribution produces a transient gravity signal, which is about 4 times larger than the allogenic one, while during the largest flood the allogenic contribution drastically overcomes the autogenic effect by a factor 20. By discussing this case, we prove the potential of terrestrial gravity observation to depict the hydro-dynamics of these complex karstic systems as well as the potential of gravimetry to remotely monitor these storage units.

Description: Published

Description: 130453

Description: JCR Journal

Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2023. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.

Description: We report on about 20 yr of relative gravity measurements, acquired on Mt. Somma–Vesuvius volcano in order to investigate the hydrological and volcano-tectonic processes controlling the present-day activity of the volcano. The retrieved long-term field of time gravity change (2003–2022) shows a pattern essentially related to the subsidence, which have affected the central part of the volcano, as detected by the permanent GNSS network and InSAR data. After reducing the observations for the effect of vertical deformation, no significant residuals are found, indicating no significant mass accumulation or loss within the volcanic system. In the north-western sector of the study area, at the border of the volcano edifice, however, significant residual positive gravity changes are detected which are associated to ground-water rebound after years of intense exploitation of the aquifers. On the seasonal timescale, we find that stations within the caldera rim are affected by the seasonal hydrological effects, while the gravity stations at the base of the Vesuvius show a less clear correlation. Furthermore, within the caldera rim a multiyear gravity transient is detected with an increase phase lasting about 4 yr followed by a slower decrease phase. Analysis of rain data seem to exclude a hydrological origin, hence, we hypothesize a deeper source related to the geothermal activity, which can be present even if the volcano is in a quiescent state. We infer the depth and volume of the source by inverting the spatial pattern of the gravity field at the peak of the transient. A volume of fluids of 9.5 × 107 m3 with density of 1000 kg m−3 at 2.3 km depth is capable to fit reasonably well the observations. To explain the gravity transient, simple synthetic models are produced, that simulate the ascent of fluids from a deep reservoir up to the depth of 2.3 km and a successive diffusion within the carbonate aquifer hosting the geothermal system. The whole process appears to not significantly affect the seismicity rate and the deformation of the volcano. This study demonstrates the importance of a 4-D gravity monitoring of a volcano to understand its complex gravity signals that cover different spatial and temporal scales. Discriminating the different contributions that mix up in the observed gravity changes, in particular those due to hydrologic/anthropogenic activities form those due to the geothermal dynamics, is fundamental for a complete and reliable evaluation of the volcano state.

Description: Published

Description: 1565–1580

Description: OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici

Description: JCR Journal

Description: The Calabrian Orogenic Arc (COA) is affected by active extensional and strike-slip tectonics as documented by the presence of N-S and NE-SW trending intra-montane basins bordered by faults, whose slip has caused many destructive earthquakes during the last millennium. By focusing on the central sector of the COA (Sila Massif) through the analysis of new seismological and geodetic datasets, we observed some relevant differences (e.g., seismic activity and hypocentral depths, faulting style, geodetic strain, vertical rates) between its western and eastern sector. The transition between the two sectors occurs in the area of the Lakes Fault, a NW-SE striking and west-dipping fault indicated as the causative source of the 8 June 1638 M 6.8 earthquake. By modelling the available geodetic data, we inferred a dislocation plane whose geometry and kinematics (a prevalent dip-slip component coupled with minor left-lateral strike-slip) is compatible with the real fault reported in literature. This fault only accounts for a small amount of the deformation across northern COA and divides the seismically more active western sector from its eastern counterpart with appreciable geodetic strain and moderate seismicity. Results are encouraging and a similar approach can help in other regions where surface evidence of active faults are rare or non-existing and field geological investigations are hence difficult.

Description: Published

Description: 384-397

Description: OST3 Vicino alla faglia

Description: JCR Journal

Description: This study explores the seismotectonics of Kachchh in western India, a region with a low-to-moderate strain rate and a history of significant earthquakes, notably the 1819, Mw 7.8 Allah Bund, and the 2001, Mw 7.6 Bhuj. Despite its substantial seismic risk, comprehensive studies on Kachchh’s seismogenic sources are scarce. This is attributed to the concealed nature of active structures, hindering definitive age constraints in paleoseismological research. Our research comprises a detailed paleoseismic analysis of the north-verging, reverse Jhura Fault underlying the Jhura anticline, a segment of the Kachchh Mainland Fault. This fault segment shows evidence of surface-rupturing earthquakes in the area south of the Great Rann of Kachchh. The investigation reveals three paleoseismic events: Event I before 9.72 ka B.P., Event II between 8.63–8.20 ka B.P., and Event III between 6.20–6.09 ka B.P. The elapsed time since the last event on this fault is 〉 8000 years, suggesting that the area is exposed to a significant earthquake hazard. This highlights the need for more precise characterization of individual seismogenic sources for future earthquake preparedness.

Description: Published

Description: 11612

Description: OST2 Deformazione e Hazard sismico e da maremoto

Description: OST3 Vicino alla faglia

Description: JCR Journal

Description: Active volcanoes show many mild thermal anomalies, because the ground surface is sensible to changes in the advective processes, occurring through the network of fissures. This data report shows the temperatures, recorded from January 2020 to February 2023, by a remote-controlled monitoring station. The VCS station is located on the summit of La Fossa cone (Vulcano, Aeolian Islands), in a zone of intense diffuse degassing. The temperature data, hourly registered at VCS, are available in the supplementary Excel file. The thermal data are part of the comprehensive network, performed by the Istituto Nazionale di Geofisica e Vulcanologia, for volcanic surveillance. On the Island of Vulcano, the active volcanic system under la Fossa caldera has been affected by multiple exhaling crises, interpreted as unrest of volcanic activity. The temperature time series provided reference data showing the thermal transition of the volcanic ground surface from a background degassing condition, through unrest, to the new thermal condition that followed the unrest period.

Description: OvFu 0304.010 - Italian Presidenza del Consiglio dei Ministri—Dipartimento della Protezione Civile

Description: Published

Description: 40

Description: OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici

Description: JCR Journal

Description: The 28th September 2018 Sulawesi Supershear earthquake (MW 7.5) was one of the deadliest earthquakes in the recent history of Indonesia causing ∼4000 causalities. The earthquake caused a ∼ 177 km long surface rupture along the Palu-Karo fault. Apart from surface rupture, the earthquake caused extensive earthquake environmental effects (EEEs) around the Palu-Donggala area of Central Sulawesi, Indonesia, which includes tsunami, coastal landslide, liquefaction, ground cracks and more than 7300 landslides in hilly areas. Initial post-event analysis and reports assigned a Modified Mercalli Intensity (MMI) of VII to VIII in Palu City and the surrounding area. Building damage and ground effects caused by the earthquake suggested that seismic intensity was understated. Here we applied the EEEs information from field survey data, published reports, and remote sensing tools to determine macroseismic intensity using the Environmental Seismic Intensity (ESI-07) Scale. The ESI-07 intensity derived from the ground effects suggests the maximum intensity of X-XI, which is 3–4° higher than the traditional intensity estimated by the United States Geological Survey (USGS) and the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). ShakeMaps were generated considering the ESI-07 values. The ShakeMap was compared with the instrumentally derived ShakeMap for the Palu earthquake, which proves that the ShakeMap prepared from the instrumental data or structural damage data is underrated. We argue that proper documentation of the EEEs is necessary for such damaging earthquakes for future earthquake hazard mapping and planning in the study area and other earthquakes in Indonesia. In addition, this will help in defining the on-fault and off-fault damage zone towards reducing the seismic risk of the Palu Donggala area.

Description: Published

Description: 107054

Description: JCR Journal

Description: Around 9.7 million years ago there was an abrupt collapse in diversity; the so-called 'Vallesian Crisis'. This was seen as the transition point to a climate with more seasonality and open landscapes.Using a fossil dataset from Miocene Eurasia, the influence of dataset quality on the severity of this crisis, which animals were most affected and their distribution patterns was studied.The crisis’ victims have three things in common: they are mainly forest dwellers, they date back to the Middle Miocene (16-11.1 Ma), and they are rare during the early Vallesian. The high Vallesian biodiversity was caused by the arrival of new immigrants in addition to older transient groups, possibly due to the unique coastal conditions.Major differences existed between the coastal region and the interior of the Iberian Peninsula. Some species appeared in the Vallès-Penedès, but never reached the inland. The 'Vallesian Crisis', while seen understandably as a time of abrupt and severe extinction, was thus largely a local turnover event.

Description: Multisensor data fusion has recently become a relevant topic in remote sensing. Versatile hyperspectral sensors and lidar scanners not only separately deal with land cover classifications but promise to improve object and material classification synergistically. Our study presents a combined workflow for land cover and roof material classification based on the fusion of hyperspectral and lidar data. An innovative 3D ResU-Net incorporates continuous high-dimensional data based on 3D convolutional operations. Our results show that feature-level-based multisensor data fusion has high potential, especially in heterogeneous urban, dynamic, and highly complex environments.

Description: Scheelite (CaWO4) is an economically important W mineral in skarns that form when magmatic fluids exsolved from a granitic intrusion react with carbonate wall rocks. In the Fujiashan W skarn deposit, scheelite formed during four stages of the hydrothermal skarn development. We present cathodoluminescence (CL) images and in situ trace element and Sr-O isotope data of scheelite from these four stages, i.e., scheelite in prograde and retrograde skarn, quartz-sulfide veins, and late calcite replacements. Scheelite from prograde skarn and quartz sulfide veins are homogeneous and show oscillatory zoning textures in CL images, whereas scheelite from retrograde skarn and late carbonate stages display dissolution-reprecipitation and patchy textures. The brightness of CL textures decreases with a higher substitution of Mo. Molybdenum-rich scheelite (up to 2.1 wt%) is characterized by relatively high contents of Nb and Ta (up to 156 and 0.9 ppm, respectively), positive Eu anomalies, high-δ18O values (5.2 to 5.9‰), and relatively low-87Sr/86Sr values (0.70661 to 0.70727), and has grown in a system with a continuous supply of magmatic fluid. Molybdenum-poor scheelite (0.2 wt%) has low contents of Nb and Ta, negative Eu anomalies, low-δ18O values (4.2 to 4.3‰), and relatively high-87Sr/86Sr ratios (0.70748 to 0.70804). This type of scheelite formed in a system with a restricted flow of magmatic fluid during scheelite precipitation became increasingly depleted in elements that substitute into scheelite. The continued reaction of the magmatic fluid with the wall rocks and the precipitation of minerals from the fluid resulted in a systematic change of the δ18O and 87Sr/86Sr ratios. Chemical and isotopic variations in scheelite may reflect the pulsed flow of a magmatic fluid and do not require the involvement of different fluids or contrasting redox conditions.

Description: Quantitative analysis of fluvial topography and sediment yield changes are often independently used to detect major river capture events and episodes of drainage reorganization. Here we use a unique set of geological and in situ 10Be cosmogenic data from Corsica, Western Mediterranean, to provide evidence of major river capture events affecting the former Paleo-Ostriconi river catchment during the Pliocene, and to illustrate how the landscape of Corsica is still reacting to the disequilibrium caused by the late Miocene uplift of Alpine Corsica. We found that ∼1280 km2 of basin area originally draining towards the Ligurian Sea were abruptly connected to the Tyrrhenian Sea by the capturing Tavignano and Golo rivers, which led to the formation of a large Pliocene-Quaternary submarine fan offshore the Tyrrhenian coast. The increased sediment yield towards the Tyrrhenian margin after river capture in the Pliocene was three times greater than the average sediment yield in the same source-to-sink system during the Holocene (410±100 t·km−2·a − 1 vs ∼131±8 t·km−2·a − 1) and greater magnitude than any subsequent peaks in sediment yield during late Pleistocene glaciations. 10Be-derived denudation rates reveal that focused erosion still affects retreating knickpoints near the sites of former river capture in central Corsica, suggesting persistence of landscape disequilibrium for several millions of years. Our results demonstrate the potentially large impact of river capture on the stratigraphic record and highlight the importance of full consideration of landscape response times to onshore disturbances for any reliable interpretation of the offshore sedimentary archive.

Description: first_page settings Order Article Reprints Open AccessFeature PaperArticle Assessing the Efficacy of A Mo2C/Peroxydisulfate System for Tertiary Wastewater Treatment: A Study of Losartan Degradation, E. coli Inactivation, and Synergistic Effects by Alexandra A. Ioannidi 1, Maria Vlachodimitropoulou 1 [ORCID] , Zacharias Frontistis 2 [ORCID] , Athanasia Petala 3, Eleni Koutra 1, Michael Kornaros 1 [ORCID] and Dionissios Mantzavinos 1,* [ORCID] 1 Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece 2 Department of Chemical Engineering, University of Western Macedonia, GR-50132 Kozani, Greece 3 Department of Environment, Ionian University, GR-29100 Zakynthos, Greece * Author to whom correspondence should be addressed. Catalysts 2023, 13(9), 1285; https://doi.org/10.3390/catal13091285 Submission received: 9 August 2023 / Revised: 3 September 2023 / Accepted: 6 September 2023 / Published: 8 September 2023 (This article belongs to the Special Issue Environmental Catalysis in Advanced Oxidation Processes, 2nd Edition) Download keyboard_arrow_down Browse Figures Versions Notes Abstract This work examines the use of pristine Mo2C as an intriguing sodium persulfate (SPS) activator for the degradation of the drug losartan (LOS). Using 500 mg/L Mo2C and 250 mg/L SPS, 500 μg/L LOS was degraded in less than 45 min. LOS decomposition was enhanced in acidic pH, while the apparent kinetic constant decreased with higher LOS concentrations. According to experiments conducted in the presence of scavengers of reactive species, sulfate radicals, hydroxyl radicals, and singlet oxygen participated in LOS oxidation, with the latter being the predominant reactive species. The presence of competitors such as bicarbonate and organic matter reduced the observed efficiency in actual matrices, while, interestingly, the addition of chloride accelerated the degradation rate. The catalyst showed remarkable stability, with complete LOS removal being retained after five sequential experiments. The system was examined for simultaneous LOS decomposition and elimination of Escherichia coli. The presence of E. coli retarded LOS destruction, resulting in only 30% removal after 3 h, while the system was capable of reducing E. coli concentration by 1.23 log. However, in the presence of simulated solar irradiation, E. coli was reduced by almost 4 log and LOS was completely degraded in 45 min, revealing a significant synergistic effect of the solar/Mo2C/SPS system.

Description: To enhance the EU's economic autonomy, feasible options for local sourcing of critical raw materials that would allow for shorter supply routes along with ethical and responsible value chains are under contemplation. Social acceptance of mining in Europe is, however, low, and the establishment of new mining sites faces strong public opposition. Therefore, innovative solutions for the production of primary raw materials need to be developed. A new idea for raw material extraction is the extraction of essential elements from geothermal fluids. Deep geothermal fluids, increasingly used for energy production, often contain high concen-trations of dissolved ions and gases in commercially interesting concentrations. The EU-funded project CRM-geothermal aims to develop new technologies to extract these highly relevant elements, including helium, during geothermal production cycles. In this way, an environmentally friendly and socially acceptable exploration and exploitation method could be deployed. One aim of the CRM-geothermal project is to gain an overview of the actual quantities of critical raw materials in various geothermal fluids in Europe by taking and analyzing fluid samples. In Turkey for instance, classical high enthalpy (volcanic) systems exist, which are representative for many geothermal areas worldwide. The sites are located at the edges of tectonic plates and close to areas undergoing volcanic activity. The brines are mixed with seawater and circulate in the deeper crust. The data publication contains analyses results of three gas samples from Tuzla, two samples from Seferihisar geothermal power plant and one sample from the Dikili geothermal field in Turkey, taken in 2023 as part of the CRM-geothermal project.

Description: Project “Saptarshi” was initiated by the National Centre for Geodesy, Indian Institute of Technology Kanpur to set up the modern space geodetic infrastructure in the country. This project primarily focuses on the establishment of an Indian Geodetic VLBI network. The purpose of this paper is to anticipate the potential impact of the geodetic VLBI network in India to the national and international scientific products. Saptarshi proposes to establish three VLBI stations along with a correlator at one facility. In this work, we investigate how adding proposed Indian VLBI antennas will affect terrestrial and celestial reference frames as well as Earth Orientation Parameters (EOP). Additionally, we shortly demonstrate scenario of VLBI observations of one of the Indian regional navigation satellite system called Navigation with Indian Constellation (NavIC) to determine its orbit. Two VLBI networks were simulated to observe the NAVIC satellite along with quasars to check how well the orbit of this satellite can be recovered from VLBI observations. To investigate the impact on the terrestrial reference frame, three types of 24-h sessions, IVS-R1 (legacy), IVS-VGOS (next generation VLBI), and IVS-AOV (Asia Oceania VLBI), were studied to examine the gain in precision of geodetic parameters when adding the proposed Indian VLBI antennas. IVS-type Intensive sessions were also investigated with the proposed Indian antennas to assess the improvement in the estimation of dUT1 as one important VLBI product. Furthermore, the u-v coverage of some radio sources of the southern hemisphere was compared utilizing observing networks with and without the proposed Indian antennas. Apart from that, we briefly discuss other benefits of the establishment of Indian geodetic VLBI in the scientific fields of atmosphere, metrology, and space missions.

Description: Background Dark pigmented snow and glacier ice algae on glaciers and ice sheets contribute to accelerating melt. The biological controls on these algae, particularly the role of viruses, remain poorly understood. Giant viruses, classified under the nucleocytoplasmic large DNA viruses (NCLDV) supergroup (phylum Nucleocytoviricota), are diverse and globally distributed. NCLDVs are known to infect eukaryotic cells in marine and freshwater environments, providing a biological control on the algal population in these ecosystems. However, there is very limited information on the diversity and ecosystem function of NCLDVs in terrestrial icy habitats. Results In this study, we investigate for the first time giant viruses and their host connections on ice and snow habitats, such as cryoconite, dark ice, ice core, red and green snow, and genomic assemblies of five cultivated Chlorophyta snow algae. Giant virus marker genes were present in almost all samples; the highest abundances were recovered from red snow and the snow algae genomic assemblies, followed by green snow and dark ice. The variety of active algae and protists in these GrIS habitats containing NCLDV marker genes suggests that infection can occur on a range of eukaryotic hosts. Metagenomic data from red and green snow contained evidence of giant virus metagenome-assembled genomes from the orders Imitervirales, Asfuvirales, and Algavirales. Conclusion Our study highlights NCLDV family signatures in snow and ice samples from the Greenland ice sheet. Giant virus metagenome-assembled genomes (GVMAGs) were found in red snow samples, and related NCLDV marker genes were identified for the first time in snow algal culture genomic assemblies; implying a relationship between the NCLDVs and snow algae. Metatranscriptomic viral genes also aligned with metagenomic sequences, suggesting that NCLDVs are an active component of the microbial community and are potential “top-down” controls of the eukaryotic algal and protistan members. This study reveals the unprecedented presence of a diverse community of NCLDVs in a variety of glacial habitats dominated by algae.

Description: Solar heating of freshwater lakes covered with ice is an important geophysical problem that has attracted researchers for many years. The main experimental and theoretical results concern solar heat accumulation in water under the ice and convective heat transfer in deep lakes. At the same time, the model of radiative transfer in light-scattering ice is too simplified and insufficient for a correct description of heat transfer, including ice melting. The present work largely compensates for this deficiency. For the first time, it is shown that a thick layer of ice begins to melt at the ice-water interface, mainly due to solar heating of the ice rather than heat flux from warmer water. The results of calculations for mountain lakes like Ngoring Lake in the northeast of the Tibetan Plateau are presented. The computational data are in good agreement with the published field observations.

Description: The Woodfjorden area of northern Spitsbergen (NW Svalbard) offers access to the world’s northernmost onshore thermal springs, extinct Pleistocene alkali basaltic volca- noes and Miocene flood basalts including extensive hyaloclastites. In July 2023, we undertook a 14-day international multi-disciplinary geoscientific expedition to Wood- fjorden-Bockfjorden to investigate the Cenozoic geological evolution of the area. The expedition objectives spanned a wide range of scientific topics from sampling of fluids and gas in the thermal springs to constraining the lithosphere by acquiring magne- totelluric data and sampling volcanic rocks. More specifically, we have 1) conducted gas, fluid and travertine sampling at the thermal springs of Gygrekjelda, Jotunkjeldene and Trollkjeldene, 2) mapped and sampled the Quaternary volcanic centers at Sverrefjel- let and Halvdanpiggen, 3) sampled the Miocene basalts of the Seidfjellet Formation along seven profiles plus the underlying Devonian sedimentary rocks, 4) acquired magnetotelluric data at 12 stations along both coasts of Woodfjorden and Bockfjorden and 5) collected extensive digital geological data (digital outcrop models and photo- spheres) using unmanned aerial vehicles (UAVs; also known as drones). The collected samples are currently being analyzed for, amongst others, petrology, geochemistry and geochronology. In this contribution, we report on the expedition’s background, scientific objectives and present selected preliminary results such as field parameters from the thermal springs (temperature, pH, electrical conductivity), magnetic susceptibility of volcanic rocks and digital outcrop models plus photospheres.

Description: Severe flood losses have been on the rise, and this trend is expected to become increasingly prevalent in the future due to climate and socio-economic changes. Swiftly identifying flooded areas is crucial for mitigating socio-economic losses and facilitating effective recovery. Synthetic aperture radar (SAR) sensors are operational in all-weather, day-and-night conditions and offer a rapid, accurate, and cost-effective means of obtaining information for quick flood mapping. However, the complex nature of SAR images, such as speckle noise, coupled with the often absence of training/labeled samples, presents significant challenges in their processing procedures. To alleviate such hindrances, we can benefit from unsupervised classification approaches (also known as clustering). Clustering methods offer valuable insights into newly acquired datasets without the need for training or labeled samples. However, traditional clustering approaches are predominantly linear-based and overlook the spatial information of neighboring pixels during analysis. Thus, to attenuate these challenges, we propose a deep-learning (DL)-based clustering approach for flood detection (DC4Flood) using SAR images. The primary advantage of DC4Flood over existing DL-based clustering approaches lies in its ability to capture multiscale spatial information. This is achieved using multiple dilated convolutions with varying dilation rates and subsequently fusing the extracted multiscale information to effectively and efficiently analyze SAR images in an unsupervised manner. Extensive experiments conducted on SAR images from six different flood events demonstrate the effectiveness of the proposed DC4Flood. The code of the work will be available at https://github.com/Kasra2020/DC4Flood .

Description: Lynchets, often the defining component of historic agricultural landscapes in northern Europe, are generally associated with soft-limestone geologies and are particularly well developed on loess-mantled landscapes. To understand their formation and chronology, the authors present their geoarchaeological analyses of lynchet soils and loess deposits at Blick Mead and Charlton Forest in southern England, and Sint Martens-Voeren in Belgium. The lynchets date from the late prehistoric to the medieval periods and were constructed by plough action at the English sites, and by both cut-and-fill and ploughing in Belgium. This has resulted in the preservation of highly fertile loessic soils across chalk slopes, lost elsewhere. Although each example is associated with local/regional agricultural histories, the lynchets’ effective soil-retention capacities allowed them to survive as important heritage features with environmental benefits over millennia.

Description: Current deep uncertainties in the projected global mean sea-level rise result from knowledge gaps in the physical processes involved in the response of the Antarctic Ice Sheet (AIS) to global warming in the coming decades to centuries (Fox-Kemper et al. 2021). Many of the ice shelves fringing Antarctica are at risk of rapid thinning, or collapse, due to oceanic and atmospheric warming, with likely impacts on the position of the ice-sheet grounding line. It is critical for the ice-sheet community to determine whether Antarctica’s margins have already crossed a tipping point, and if so, when and how much mass loss will take place. A multi-disciplinary approach is required to advance the state of knowledge on tipping points spanning a large range of spatio-temporal scales and components of the polar-climate system. This is the overarching objective of the SCAR Instabilities and Thresholds in Antarctica (INSTANT) Scientific Research Programme (Colleoni et al. 2022). ...

Description: Cryoconite holes (water and sediment-filled depressions), found on glacier surfaces worldwide, serve as reservoirs of microbes, carbon, trace elements, and nutrients, transferring these components downstream via glacier hydrological networks. Through targeted amplicon sequencing of carbon and nitrogen cycling genes, coupled with functional inference-based methods, we explore the functional diversity of these mini-ecosystems within Antarctica and the Himalayas. These regions showcase distinct environmental gradients and experience varying rates of environmental change influenced by global climatic shifts. Analysis revealed a diverse array of photosynthetic microorganisms, including Stramenopiles, Cyanobacteria, Rhizobiales, Burkholderiales, and photosynthetic purple sulfur Proteobacteria. Functional inference highlighted the high potential for carbohydrate, amino acid, and lipid metabolism in the Himalayan region, where organic carbon concentrations surpassed those in Antarctica by up to 2 orders of magnitude. Nitrogen cycling processes, including fixation, nitrification, and denitrification, are evident, with Antarctic cryoconite exhibiting a pronounced capacity for nitrogen fixation, potentially compensating for the limited nitrate concentrations in this region. Processes associated with the respiration of elemental sulfur and inorganic sulfur compounds such as sulfate, sulfite, thiosulfate, and sulfide suggest the presence of a complete sulfur cycle. The Himalayan region exhibits a higher potential for sulfur cycling, likely due to the abundant sulfate ions and sulfur-bearing minerals in this region. The capability for complete iron cycling through iron oxidation and reduction reactions was also predicted. Methanogenic archaea that produce methane during organic matter decomposition and methanotrophic bacteria that utilize methane as carbon and energy sources co-exist in the cryoconite, suggesting that these niches support the complete cycling of methane. Additionally, the presence of various microfauna suggests the existence of a complex food web. Collectively, these results indicate that cryoconite holes are self-sustaining ecosystems that drive elemental cycles on glaciers and potentially control carbon, nitrogen, sulfur, and iron exports downstream.

Description: Age-progressive seamount tracks generated by lithospheric motion over a stationary mantle plume have long been used to reconstruct absolute plate motion (APM) models. However, the basis of these models requires the plumes to move significantly slower than the overriding lithosphere. When a plume interacts with a convergent or divergent plate boundary, it is often deflected within the strong local mantle flow fields associated with such regimes. Here, we examined the age progression and geometry of the Samoa hotspot track, focusing on lava flow samples dredged from the deep flanks of seamounts in order to best reconstruct when a given seamount was overlying the mantle plume (i.e., during the shield-building stage). The Samoan seamounts display an apparent local plate velocity of 7.8 cm/yr from 0 to 9 Ma, 11.1 cm/yr from 9 to 14 Ma, and 5.6 cm/yr from 14 to 24 Ma. Current fixed and mobile hotspot Pacific APM models cannot reproduce the geometry of the Samoa seamount track if a long-term fixed hotspot location, currently beneath the active Vailulu’u Seamount, is assumed. Rather, reconstruction of the eruptive locations of the Samoan seamounts using APM models indicates that the surface expression of the plume migrated ~2° northward in the Pliocene. Large-scale mantle flow beneath the Pacific Ocean Basin cannot explain this plume migration. Instead, the best explanation is that toroidal flow fields—generated by westward migration of the Tonga Trench and associated slab rollback—have deflected the conduit northward over the past 2–3 m.y. These observations provide novel constraints on the ways in which plume-trench interactions can alter hotspot track geometries.

Description: The Martian surface and shallow subsurface lacks stable liquid water, yet hygroscopic salts in the regolith may enable the transient formation of liquid brines. This study investigated the combined impact of water scarcity, UV exposure, and regolith depth on microbial survival under Marslike environmental conditions. Both vegetative cells of Debaryomyces hansenii and Planococcus halocryophilus, alongside with spores of Aspergillus niger, were exposed to an experimental chamber simulating Martian environmental conditions (constant temperatures of about − 11 °C, low pressure of approximately 6 mbar, a CO2 atmosphere, and 2 h of daily UV irradiation). We evaluated colonyforming units (CFU) and water content at three different regolith depths before and after exposure periods of 3 and 7 days, respectively. Each organism was tested under three conditions: one without the addition of salts to the regolith, one containing sodium chlorate, and one with sodium perchlorate. Our results reveal that the residual water content after the exposure experiments increased with regolith depth, along with the organism survival rates in chlorate-containing and salt-free samples. The survival rates of the three organisms in perchlorate-containing regolith were consistently lower for all organisms and depths compared to chlorate, with the most significant difference being observed at a depth of 10–12 cm, which corresponds to the depth with the highest residual water content. The postulated reason for this is an increase in the salt concentration at this depth due to the freezing of water, showing that for these organisms, perchlorate brines are more toxic than chlorate brines under the experimental conditions. This underscores the significance of chlorate salts when considering the habitability of Martian environments.

Description: Although river water storage contributes to Total Terrestrial Water Storage (TWS) variations obtained from GRACE satellite gravimetry, it is unclear if computationally expensive river routing schemes are required when GRACE data is used for calibration and validation in global hydrological modeling studies. Here, we investigate the role of river water storage on calibration and validation of a parsimonious global hydrological model. In a multi-criteria calibration approach, the model is constrained against either GRACE TWS or TWS from which river water storage is removed. While we find that removing river water storage changes the TWS constraint regionally and globally, there are no significant implications for model calibration and the resulting simulations. However, adding modeled river water storage a-posteriori to calibrated TWS simulations improves model validation against seasonal GRACE TWS variations globally and regionally, especially in tropics and Northern low- and wetlands. While our findings justify the exclusion of explicit river routing for global model calibration, we find that the inclusion of river water storage is relevant for model evaluation.

Description: More than 20 yr of measurement data of the gravity missions GRACE (Gravity Recovery And Climate Experiment) and GRACE-FO (GRACE-Follow-On) allow detailed investigations of long-term trends in continental terrestrial water storage (TWS). However, the spatial resolution of conventional GRACE/GRACE-FO data products is limited to a few hundred kilometres which restrains from investigating hydrological trends at smaller spatial scales. In this study GRACE and GRACE-FO data have been used to calculate TWS trends with maximized spatial resolution. Conventionally, GRACE/GRACE-FO is presented as a series of either unconstrained gravity fields post-processed with spatial low pass filters or constrained inversions commonly known as Mascon products. This paper demonstrates that both approaches to suppress spatially correlated noise are mathematically equivalent. Moreover, we demonstrate that readily inverting all available sensor data from GRACE/GRACE-FO for a single TWS trend map, together with annual variations and a mean gravity field, provides additional spatial detail not accessible from the standard products. The variable trade-off between spatial and temporal resolution as a unique feature of satellite gravimetry allows for gravity products that are tailored towards specific geophysical applications. We show additional signal content in terms of long-term water storage trends for four dedicated examples (Lake Victoria, Northwest India, Bugachany Reservoir and High Plains Aquifer) for which external information from other remote sensing instruments corroborates the enhanced spatial resolution of the new mean-field trend product.

Description: The deepest geoid low globally with respect to hydrostatic equilibrium is in the Ross Sea area. Nearby in West Antarctica is a residual topography high. Both are in a region with thin lithosphere, where a mantle plume has been suggested. Hence upper mantle viscosity could be regionally reduced, allowing for faster rebound than elsewhere upon melting of the West Antarctic Ice Sheet, one of the global climate system’s tipping elements. To study possible causes of the geoid low / topography high combination, we compute the effects of disk-shaped density anomalies. With -1% density anomaly and a global average radial viscosity structure, geoid low and topography high can be explained with disk radius about 10° and depth range ~150-650 km. Alternatively, there may be two separate disks somewhat laterally displaced, one just below the lithosphere and mainly causing a dynamic topography high and one below the transition zone causing the geoid low. If viscosity in the uppermost mantle is reduced by a factor 10 (from 50 to 350 km depth) to 100 (from 100 to 220 km), one shallow disk in the depth range 50-350 km would also be sufficient. In order to test the feasibility of such density models, we perform computations of a thermal plume that enters at the base of a cartesian box corresponding to a region in the upper mantle, as well as some whole-mantle thermal plume models, with ASPECT. These plume models have typically a narrow conduit and the plume tends to only become wider as it spreads beneath the lithosphere, typically shallower than ~300 km. These results are most consistent with the shallow disk model with reduced uppermost mantle viscosity, hence providing further support for such low viscosities beneath West Antarctica.

Description: Geyser geothermal fields are scenic volcanic landforms that often contain tens to hundreds of thermal spot vents that erupt boiling water or contain bubbling mud pools. The fields are potentially hazardous sites due to boiling water temperatures and changes in vent locations and eruption dynamics, which are poorly understood. Here we report on the rapid and profound changes that can affect such a geyser field and ultimately lead to a dangerous, unanticipated eruption. We studied the Geyser Valley, Kamchatka Peninsula, which is a field of geysers and other thermal features and boiling pools. Using high-resolution tri-stereo satellite data and unmanned aerial systems (UAS) with optical and thermal infrared cameras in 2018 and 2019, we were able to identify a newly emerging explosion site. Structure-from-motion analysis of data acquired before and after the explosion reveals morphological and thermal details of the new vent. The explosion site produced an aureole zone of more than 150 m3 of explosively redeposited gravel and clay, a slightly elliptical crater with a diameter of 7.5 m and a crater rim 0.30 m high. However, comparison with archives of photogrammetric data suggests that this site was thermally active years earlier and contained a crater that was obscured and covered by landslides and river sediments. The results allow us to develop a conceptual model and highlight the hazard potential of thermal features buried by landslides and clastic deposits. Sudden explosions may occur at similar sites elsewhere, highlighting the need for careful assessment and monitoring of geomorphological and hydrological changes at geyser sites in other regions.

Description: The large Weilasituo Sn-polymetallic deposit is a recent exploration discovery in the southern Great Xing’an Range, northeast China. The ore cluster area shows horizontal mineralization zoning, from the inner granite body outward, consisting of high-T Sn–W–Li mineralization, middle-T Cu–Zn mineralization and peripheral low-T Pb–Zn–Ag mineralization. However, the intrinsic genetic relationship between Sn-W-Li mineralization and peripheral vein-type Pb–Zn–Ag–Cu mineralization, the formation mechanism and the deep geological background are still insufficiently understood. Here, we use fluid inclusions, trace elements concentrations in quartz and sphalerite, and H–O isotope studies to determine the genetic mechanism and establish a metallogenic model. Fluid inclusion microthermometry and Laser Raman spectroscopic analysis results demonstrates that the aqueous ore-forming fluids evolved from low-medium salinity, medium–high temperature to low salinity, low-medium temperature fluids. Laser Raman spectroscopic analysis shows that CH4 is ubiquitous in fluid inclusions of all ore stages. Early ore fluids have δ18OH2O (v–SMOW) values from + 5.5 to + 6.2‰ and δD values of approximately − 67‰, concordant with a magmatic origin. However, the late ore fluids shifted toward lower δ18OH2O (v–SMOW) (as low as 0.3‰) and δD values (~ − 136‰), suggesting mixing between external fluids derived from the wall rocks and a contribution from meteoric water. Ti-in-quartz thermometry indicates a magmatic crystallization temperature of around 700 °C at a pressure of 1.5 kbar for the magmatic ore stage. Cathodoluminescence (CL) imaging and trace element analysis of quartz from a hydrothermal vug highlight at least three growth episodes that relate to different fluid pulses; each episode begins with CL-bright, Al-Li-rich quartz, and ends with CL-dark quartz with low Al and Li contents. Quartz from Episode 1 formed from early Sn-(Zn)-rich fluids which were likely derived from the quartz porphyry. Quartz from episodes 2 and 3 formed from Zn-(Sn)-Cu-rich fluid. The early magmatic fluid is characterized by low fS2. The SO2 produced by magma degassing reacted with heated water to form SO42−, causing the shift from low fS2 to high fS2. The SO42− generated was converted to S2– by mixing with CH4-rich, Fe and Zn-bearing external fluid which led to late-stage alteration and dissolution of micas in vein walls, thus promoting crystallization of pyrrhotite, Fe-rich sphalerite and chalcopyrite and inhibiting the precipitation of anhydrite. This study shows that ore formation encompassed multiple episodes involving steadily evolved fluids, and that the addition of external fluids plays an important role in the formation of the later Cu–Zn and Ag–Pb–Zn mineralization in the Weilasituo ore district.

Description: So far, various studies have aimed at decomposing the integrated terrestrial water storage variations observed by satellite gravimetry (GRACE, GRACE-FO) with the help of large-scale hydrological models. While the results of the storage decomposition depend on model structure, little attention has been given to the impact of the way that vegetation is represented in these models. Although vegetation structure and activity represent the crucial link between water, carbon, and energy cycles, their representation in large-scale hydrological models remains a major source of uncertainty. At the same time, the increasing availability and quality of Earth-observation-based vegetation data provide valuable information with good prospects for improving model simulations and gaining better insights into the role of vegetation within the global water cycle. In this study, we use observation-based vegetation information such as vegetation indices and rooting depths for spatializing the parameters of a simple global hydrological model to define infiltration, root water uptake, and transpiration processes. The parameters are further constrained by considering observations of terrestrial water storage anomalies (TWS), soil moisture, evapotranspiration (ET) and gridded runoff (Q) estimates in a multi-criteria calibration approach. We assess the implications of including varying vegetation characteristics on the simulation results, with a particular focus on the partitioning between water storage components. To isolate the effect of vegetation, we compare a model experiment in which vegetation parameters vary in space and time to a baseline experiment in which all parameters are calibrated as static, globally uniform values. Both experiments show good overall performance, but explicitly including varying vegetation data leads to even better performance and more physically plausible parameter values. The largest improvements regarding TWS and ET are seen in supply-limited (semi-arid) regions and in the tropics, whereas Q simulations improve mainly in northern latitudes. While the total fluxes and storages are similar, accounting for vegetation substantially changes the contributions of different soil water storage components to the TWS variations. This suggests an important role of the representation of vegetation in hydrological models for interpreting TWS variations. Our simulations further indicate a major effect of deeper moisture storages and groundwater–soil moisture–vegetation interactions as a key to understanding TWS variations. We highlight the need for further observations to identify the adequate model structure rather than only model parameters for a reasonable representation and interpretation of vegetation–water interactions.

Description: This study investigates the decades-long evolution of groundwater dynamics and thermal field in the North German Basin beneath Brandenburg (NE Germany) by coupling a distributed hydrologic model with a 3D groundwater model. We found that hydraulic gradients, acting as the main driver of the groundwater flow in the studied basin, are not exclusively influenced by present-day topographic gradients. Instead, structural dip and stratification of rock units and the presence of permeability contrasts and anisotropy are important co-players affecting the flow in deep seated saline aquifers at depths 〉500 m. In contrast, recharge variability and anthropogenic activities contribute to groundwater dynamics in the shallow (〈500 m) freshwater Quaternary aquifers. Recharge fluxes, as derived from the hydrologic model and assigned to the parametrized regional groundwater model, reproduce magnitudes of recorded seasonal groundwater level changes. Nonetheless, observed instances of inter-annual fluctuations and a gradual decline of groundwater levels highlight the need to consider damping of the recharge signal and additional sinks, like pumping, in the model, in order to reconcile long-term groundwater level trends. Seasonal changes in near-surface groundwater temperature and the continuous warming due to conductive heat exchange with the atmosphere are locally enhanced by forced advection, especially in areas of high hydraulic gradients. The main factors controlling the depth of temperature disturbance include the magnitude of surface temperature variations, the subsurface permeability field, and the rate of recharge. Our results demonstrate the maximum depth extent and the response times of the groundwater system subjected to non-linear interactions between local geological variability and climate conditions.

Description: Millennial-scale dry events in the Northern Hemisphere monsoon regions during the last Glacial period are commonly attributed to southward shifts of the Intertropical Convergence Zone (ITCZ) associated with an intensification of the northeasterly (NE) trade wind system during intervals of reduced Atlantic meridional overturning circulation (AMOC). Through the use of high-resolution last deglaciation pollen records from the continental slope off Senegal, our data show that one of the longest and most extreme droughts in the western Sahel history, which occurred during the North Atlantic Heinrich Stadial 1 (HS1), displayed a succession of three major phases. These phases progressed from an interval of maximum pollen representation of Saharan elements between ~19 and 17.4 kyr BP indicating the onset of aridity and intensified NE trade winds, followed by a millennial interlude of reduced input of Saharan pollen and increased input of Sahelian pollen, to a final phase between ~16.2 and 15 kyr BP that was characterized by a second maximum of Saharan pollen abundances. This change in the pollen assemblage indicates a mid-HS1 interlude of NE trade wind relaxation, occurring between two distinct trade wind maxima, along with an intensified mid-tropospheric African Easterly Jet (AEJ) indicating a substantial change in West African atmospheric processes. The pollen data thus suggest that although the NE trades have weakened, the Sahel drought remained severe during this time interval. Therefore, a simple strengthening of trade winds and a southward shift of the West African monsoon trough alone cannot fully explain millennial-scale Sahel droughts during periods of AMOC weakening. Instead, we suggest that an intensification of the AEJ is needed to explain the persistence of the drought during HS1. Simulations with the Community Climate System Model indicate that an intensified AEJ during periods of reduced AMOC affected the North African climate by enhancing moisture divergence over the West African realm, thereby extending the Sahel drought for about 4000 years.

Description: An organic-walled dinoflagellate cyst analysis was carried out on 53 surface sediment samples from West Africa (17-6°N) to obtain insight in the relationship between their spatial distribution and hydrological conditions in the upper water column as well as marine productivity in the study area. Multivariate analysis of the dinoflagellate cyst relative abundances and environmental parameters of the water column shows that sea-surface temperature, salinity, marine productivity and bottom water oxygen are the factors that relate significantly to the distribution patterns of individual species in the region. The composition of cyst assemblages and dinoflagellate cyst concentrations allows the identification of four hydrographic regimes; 1) the northern regime between 17 and 14°N characterized by high productivity associated with seasonal coastal upwelling, 2) the southern regime between 12 and 6°N associated with high-nutrient waters influenced by river discharge 3) the intermediate regime between 14 and 12°N influenced mainly by seasonal coastal upwelling additionally associated with fluvial input of terrestrial nutrients and 4) the offshore regime characterized by low chlorophyll-a concentrations in upper waters and high bottom water oxygen concentrations. Our data show that cysts of Polykrikos kofoidii, Selenopemphix quanta, Dubridinium spp., Echinidinium species, cysts of Protoperidinium monospinum and Spiniferites pachydermus are the best proxies to reconstruct the boundary between the NE trade winds and the monsoon winds in the subtropical eastern Atlantic Ocean. The association of Bitectatodinium spongium, Lejeunecysta oliva, Quinquecuspis concreta, Selenopemphix nephroides, Trinovantedinium applanatum can be used to reconstruct past river outflow variations within this region.

Description: Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt ( 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and shows that initial dry conditions were followed by a strong and rapid increase in humidity between ca. 2900 and 2500 cal yr BP. After ca. 2500 cal yr BP, the environment slowly became drier again as indicated by slight increases in Sahelian savannah and desert elements in the pollen record. Around ca. 2200 cal yr BP, this relatively dry period ended with periodic pulses of high terrigenous contributions and strong fluctuations in fern spore and river plume dinoflagellate cyst percentages as well as in the fluxes of pollen, dinoflagellate cysts, fresh-water algae and plant cuticles, suggesting "episodic flash flood" events of the Senegal River. The driest phase developed after about 2100 cal yr BP.

Description: Although grassland and savanna occupy only a quarter of the world's vegetation, burning in these ecosystems accounts for roughly half the global carbon emissions from fire. However, the processes that govern changes in grassland burning are poorly understood, particularly on time scales beyond satellite records. We analyzed microcharcoal, sediments, and geochemistry in a high-resolution marine sediment core off Namibia to identify the processes that have controlled biomass burning in southern African grassland ecosystems under large, multimillennial-scale climate changes. Six fire cycles occurred during the past 170,000 y in southern Africa that correspond both in timing and magnitude to the precessional forcing of north-south shifts in the Intertropical Convergence Zone. Contrary to the conventional expectation that fire increases with higher temperatures and increased drought, we found that wetter and cooler climates cause increased burning in the study region, owing to a shift in rainfall amount and seasonality (and thus vegetation flammability). We also show that charcoal morphology (i.e., the particle's length-to-width ratio) can be used to reconstruct changes in fire activity as well as biome shifts over time. Our results provide essential context for understanding current and future grassland-fire dynamics and their associated carbon emissions.

Description: Atmospheric and oceanographic interactions between the Atlantic and Indian Oceans influence upwelling in the southern Benguela upwelling system. In order to obtain a better knowledge of paleoceanographic and paleoenvironmental changes in the southern Benguela region during the Holocene, 12 marine surface sediment samples and one gravity core GeoB8331-4 from the Namaqualand mudbelt off the west coast of South Africa have been studied for organic-walled dinoflagellate cysts in high temporal resolution. The results are compared with pollen and geochemical records from the same samples. Our study emphasizes significantly distinct histories in upwelling intensity as well as the influence of fluvial input during the Holocene. Three main phases were identified for the Holocene. High percentages of cysts produced by autotrophic taxa like Operculodinium centrocarpum and Spiniferites spp. indicate warmer and stratified conditions during the early Holocene (9900-8400 cal. yr BP), suggesting reduced upwelling likely due to a northward shift of the southern westerlies. In contrast, the middle Holocene (8400-3100 cal. yr BP) is characterized by a strong increase in heterotrophic taxa in particular Lejeunecysta paratenella and Echinidinium spp. at the expense of autotrophic taxa. This indicates cool and nutrient-rich waters with active upwelling probably caused by a southward shift of the southern westerlies. During the late Holocene (3100 cal. yr BP to modern), Brigantedinium spp. and other abundant taxa interpreted to indicate fluvial nutrient input such as cyst of Protoperidinium americanum and Lejeunecysta oliva imply strong river discharge with high nutrient supply between 3100 and 640 cal. yr BP.

Description: In order to investigate a possible connection between tropical northeast (NE) Atlantic primary productivity, Atlantic meridional overturning circulation (AMOC), and drought in the Sahel region during Heinrich Stadial 1 (HS1), we used dinoflagellate cyst (dinocyst) assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes (d13C) and geochemical parameters of a marine sediment core (GeoB 9508-5) from the continental slope offshore Senegal. Our results show a two-phase productivity pattern within HS1 that progressed from an interval of low marine productivity between ~ 19 and 16 kyr BP to a phase with an abrupt and large productivity increase from ~ 16 to 15 kyr BP. The second phase is characterized by distinct heavy planktonic d13C values and high concentrations of heterotrophic dinocysts in addition to a significant cooling signal based on reconstructions of past sea surface temperatures (SST). We conclude that productivity variations within HS1 can be attributed to a substantial shift of West African atmospheric processes. Taken together our results indicate a significant intensification of the North East (NE) trade winds over West Africa leading to more intense upwelling during the last millennium of HS1 between ~ 16 and 15 kyr BP, thus leaving a strong imprint on the dinocyst assemblages and sea surface conditions. Therefore, the two-phase productivity pattern indicates a complex hydrographic setting suggesting that HS1 cannot be regarded as uniform as previously thought.

Description: We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo- fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from analyses of the interannual variability in biomass burning shown by remote-sensing observations of month-by-month burnt area between 1996 and 2008, our results signal a serious cause for concern in the face of continuing global warming.

Description: Terrestrial signals in marine sediment archives are often used for paleoclimatic reconstructions. It is therefore important to know the origin of the different terrestrial sedimentary components. The proximity to a river mouth is often the key location to determine the source. Especially in regions with strong ocean currents, such an assumption might,however, lead to considerable misinterpretations. To investigate the source of various terrigenous sediment fractions in southeastern Africa, a region with strong sediment redistribution, we have performed an extensive comparison between terrestrial material (pollen, plant lipids, detrital modes and heavy minerals as well as bulk inorganic geochemical composition) from potential source regions and the same components in the adjacent coastal and continental shelf sediments. Onshore the proxy‐indicators reflect small‐scale diversity in sampling locations and associated environments (riverbank sediments, flood deposits, suspension loads and soils). Nevertheless, the overall trends reflect significant environmental gradients along a SW to NE transect. We note a general comparability of the studied parameters between the continental and marine sediments regardless of their specific differences in transport and depositional characteristics. We propose that the influence of the Agulhas Current affects sediment deposition and distribution only seaward of the mid‐shelf and that pockets of sediment remain preserved in the lee of coastal protrusions where they are protected from erosion. This study provides the essential prerequisite to allow the attribution of temporal variations of compositional changes in marine sediment cores to environmental changes in southeastern Africa.

Description: Morocco is an area subject to recurrent severe droughts, desertification and an increasing land degradation. It is within a Mediterranean hotspot of biodiversity as it harbors many threatened endemic species such as the argan tree (Argania spinosa). In this context, past climate records are needed to analyze the impact of climate variability on the occurrence and future persistence of these endemic species. In order to evaluate the impact of past climate changes on the endemic Argan tree in southern Morocco, we reconstructed its modern range using an extensive pollen dataset. The modern pollen distribution off southwestern Morocco was then utilized to interpret the high-resolution pollen record with complementary micro-charcoal and XRF element records from a marine sediment core GeoB8601-3 off Cape Ghir in southwestern Morocco covering the last three millennia. This multi-proxy study has shown clear evidence of wetter conditions resulting in higher fluvial input which could be correlated with a negative mode of the North Atlantic Oscillation (NAO), in contrast to the published pollen and XRF element records from another nearby core that showed limited effect of climate changes. On the other hand, clear opposite trend between the pollen occurrences of Argania spinosa and the fire frequency was observed throughout our fossil record. The increase of Argania spinosa pollen occurrences, along with herbaceous taxa, and lower fire frequency might suggest an increase in human impact on the landscape leading to a sparse vegetation cover and subsequently increased erosion. The reconstructed pollen-based vegetation, micro-charcoal-based fire activities and geochemical changes in our marine record suggest interplay of climate and anthropogenic effects on the landscape.

Description: We analysed changes in mean air annual temperature (MAAT), vegetation and biomass burning on a long and continuous lake-peat sediment record from the Colônia basin, southeastern Brazil, examining the responses of a wet tropical rainforest over the last 180 ka. Stronger southern atmospheric circulation up to the latitude of Colônia was found for the penultimate glacial with lower temperatures than during the last glacial, while strengthening of the South American summer monsoon (SASM) circulation started during the last interglacial and progressively enhanced a longer wet summer season from 95 ka until the present. Past MAAT variations and fire history were possibly modulated by eccentricity, although with signatures which differ in average and in amplitude between the last 180 ka. Vegetation responses were driven by the interplay between the SASM and southern circulation linked to Antarctic ice volume, inferred by the presence of a cool mixed evergreen forest from 180 to 45 ka progressively replaced by a rainforest. We report cooler temperatures during the marine isotope stage 3 (MIS 3: 57-29 ka) than during the Last Glacial Maximum (LGM: 23-19 ka). Our findings show that tropical forest dynamics display different patterns than mid-latitude during the last 180 ka.

Description: Compared to the rest of the globe, the Arctic Ocean is affected disproportionately by climate change. Despite these fast environmental changes, we currently know little about the effects of ocean acidification (OA) on marine key species in this area. Moreover, the existing studies typically test the effects of OA under constant, hence artificial light fields. In this study, the abundant Arctic picoeukaryote Micromonas pusilla was acclimated to current (400 μatm) and future (900 μatm) pCO2 levels under a constant as well as dynamic light, simulating more realistic light fields as experienced in the upper mixed layer. To describe and understand the responses to these drivers, growth, particulate organic carbon (POC) production, elemental composition, photophysiology and reactive oxygen species (ROS) production were analysed. M. pusilla was able to benefit from OA on various scales, ranging from an increase in growth rates to enhanced photosynthetic capacity, irrespective of the light regime. These beneficial effects were, however, not reflected in the POC production rates, which can be explained by energy partitioning towards cell division rather than biomass build-up. In the dynamic light regime, M. pusilla was able to optimise its photophysiology for effective light usage during both low and high light periods. This effective photoacclimation, which was achieved by modifications to photosystem II (PSII), imposed high metabolic costs leading to a reduction in growth and POC production rates when compared to constant light. There were no significant interactions observed between dynamic light and OA, indicating that M. pusilla was able maintain effective photoacclimation without increased photoinactivation under high pCO2. Based on these findings, M. pusilla may exhibit a robust positive response to future Arctic Ocean conditions

Description: Organic-walled dinoflagellate cyst of marine surface sediments and two sediment cores (GeoB8601-3 and GeoB4223-1) off southwestern Morocco.

Description: Marine sediment core GL-1248 was collected from the continental slope off northern northeastern Brazil by Petrobras oil company. Sediment samples (154 in total) were collected with 2 cm wide scoops at every 10 cm from the uppermost 16 m (covering the the last 113 thousand years) of the marine sediment core GL-1248. Samples were oven‐dried at 60°C, precisely weighted to 0.5 g and treated with H2O2 27% and HCl 10% to remove organic matter and calcium carbonate, respectively. The remaining content was diluted in alcohol and three aliquots per sample were mounted on stainless steel discs with four drops of the homogenized solution of alcohol and silt/clay sediments. GL-1248 luminescence measurements were performed on an automated Lexsyg Smart TL/OSL reader equipped with blue and infrared LEDs, Hoya U-340 filters for light detection in the ultraviolet band (270-390 nm) using a photomultiplier and beta radiation sources (90Sr/90Y) with doses rate of 0.116 Gy s-1 at the Luminescence and Gamma Spectrometry Laboratory of the Institute of Geosciences, University of São Paulo, Brazil. The sensitivity representative of the 110°C thermoluminesce (TL) peak of quartz considered the 80–120°C integration range from the TL curve. The 80-120°C TL sensitivity was calculated as a percentage of the total TL emission (0-250°C) and using the background TL curve. The mean of three measured aliquots represents the TL sensitivity of each sample. The OSL sensitivity was calculated by integrating the first second of light emission and the last ten seconds as background. GL-1248 TL sensitivity data were compared to previously published data obtained from marine sediment core GeoB16206-1 (https://doi.org/10.1594/PANGAEA.904357). Marine sediment core GeoB16206-1 was analyzed in a different luminescence reader (i.e. RisØ OSL/TL DA-20 reader) and using different regeneration dose. In order to avoid machine artifacts and the influence of dose size on sensitivity, we normalized the TL data output from both marine sediment cores and produced a composite record. Name of the Campaign: collected by the Petrobras oil company Event Label: GL1248 (GL-1248) Method: quarzt luminescence sensitivity Latitude: -0.920000 Longitude: -43.401667 Elevation: -2,264 m

Description: The dataset represent pollen, non-pollen palynomorphs, LOI, micro- and macrocharcoal and C14 records from core Razdolye, Kursk region, Russia. The core Razdolye was collected in 2009 by Lyudmila Shumilovskikh, Frank Schlütz, Jens Schneeweiß and Oleg Radyush with a Russian corer. Laboratory processing for palynological studies took place in the Dep. Palynology and Climate Dynamics, Georg-August-University of Göttingen in 2009 by Lyudmila Shumilovskikh and 2020 by Monika Schmidt. For each palynological sample, one millilitre of material was treated with hydrochloric acid, potassium hydroxide, hydrofluoric acid, acetolysis mixture, microsieved (6 μm) and stored in glycerol. Before acid, Lycopodium spores were added to calculate pollen influx. Microscopic identification and counting were carried out by Monika Schmidt. Standard microscopical magnification was 400×, for ambiguous objects 1000x with oil immersion. Identification and morphological pollen types follow Beug (2004) and type collections of the Dep. Palynology and Climate Dynamics, Georg-August-University of Göttingen. Non-pollen palynomorphs (NPP) follow Miola (2012) and the Non-Pollen Palynomorphs Image Database (NPP ID, http://non-pollen-palynomorphs.uni-goettingen.de/). New NPP types were described and have been uploaded to the Non-Pollen Palynomorphs Image Database (NPP ID, http://non-pollen-palynomorphs.uni-goettingen.de/). In addition, pieces of burnt plant fragments of 〉 50 µm were counted. Laboratory processing for macrocharcoal took place in the Dep. Palynology and Climate Dynamics, Georg-August-University of Göttingen in 2020 by Monika Schmidt. These samples were treated in the laboratory in Sodium Hexametaphosphate and in bleach, living overnight after each treatment and followed by sieving through 125 µm sieve. Counting of charcoal particles was carried out under a binocular microscope under 10× to 15× magnification. Samples for loss-on-ignition was processed by Monika Schmidt in 2021. Samples (1 ml) were obtained at 2 cm intervals (44 samples). LOI samples were oven-dried for 22 hours at 105 °C, for 4 hours at 550 °C and for 2 hours at 950 °C (Dean 1974; Heiri et al. 2001). LOI records are given as percentages. For an absolute chronology, bulk samples, macroremains and pollen were dated by the radiocarbon laboratories of Poznan (Poland).

Description: Summary statistics of posterior marginal distribution of the onset of abrupt warming transitions located in the last glacial age of the NGRIP record, based on both the d18O and Ca2+ proxy. Includes both statistics for the onset depth as well as age transition. Onset depth is found by applying a linear ramp function (Erhardt et al. 2019) which is combined with a probabilistic age-depth model to infer the onset age of the transition.

Description: This data set presents the reconstructed vegetation cover for 3491 sites based on harmonized pollen data from the data set LegacyPollen 2.0 (https://doi.pangaea.de/10.1594/PANGAEA.965907). 1115 sites are located in North America, 1435 in Europe, 533 in Asia, 173 in South America, 155 in Africa, and 80 in the Indopacific. Sugita's REVEALS model (2007) was applied to all pollen records using REVEALSinR from the DISQOVER package (Theuerkauf et al. 2016). Pollen counts were translated into vegetation cover by accounting for taxon-specific pollen productivity and fall speed. Additionally, relevant source areas of pollen were calculated using the aforementioned taxon-specific parameters and a gaussian plume model for deposition and dispersal. Values for relative pollen productivity and fall speed from the synthesis from Wiezcorek and Herzschuh (2010) were used for the reconstruction of vegetation cover. The average values from all Northern Hemisphere values were used where taxon-specific continental values were not available. This includes records of the Southern Hemisphere. We present tables with reconstructed vegetation cover for all continents with original parameters. As further details we list a table with the taxon-specific parameters used and a list of parameters adjusted in the default version of REVEALSinR.

Description: Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ~120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome) for the last glacial as well as for other glacial periods of the past 300 Ka.

Description: All species of coccolithophore appear to respond to perturbations of carbonate chemistry in a different way. Here, we show that the degree of malformation, growth rate and stable isotopic composition of organic matter and carbonate produced by two contrasting species of coccolithophore (Gephyrocapsa oceanica and Coccolithus pelagicus ssp. braarudii) are indicative of differences between their photosynthetic and calcification response to changing DIC levels (ranging from ~1100 to ~7800 µmol/kg) at constant pH (8.13 ± 0.02). Gephyrocapsa oceanica thrived under all conditions of DIC, showing evidence of increased growth rates at higher DIC, but C. braarudii was detrimentally affected at high DIC showing signs of malformation, and decreased growth rates. The carbon isotopic fractionation into organic matter and the coccoliths suggests that C. braarudii utilises a common internal pool of carbon for calcification and photosynthesis but G. oceanica relies on independent supplies for each process. All coccolithophores appear to utilize bicarbonate as their ultimate source of carbon for calcification resulting in the release of a proton. But, we suggest that this proton can be harnessed to enhance the supply of CO2(aq) for photosynthesis either from a large internal HCO3- pool which acts as a pH buffer (C. braarudii), or pumped externally to aid the diffusive supply of CO2 across the membrane from the abundant HCO3- (G. oceanica), likely mediated by an internal and external carbonic anhydrase respectively. Our simplified hypothetical spectrum of physiologies may provide a context to understand different species response to changing pH and DIC, the species-specific delta p and calcite "vital effects", as well as accounting for geological trends in coccolithophore cell size.

Description: The present study investigates the combined effect of phosphorous limitation, elevated partial pressure of CO2 (pCO2) and temperature on a calcifying strain of Emiliania huxleyi (PML B92/11) by means of a fully controlled continuous culture facility. Two levels of phosphorous limitation were consecutively applied by renewal of culture media (N:P = 26) at dilution rates (D) of 0.3 d- and 0.1 d-1. CO2 and temperature conditions were 300, 550 and 900 µatm pCO2 at 14 °C and 900 µatm pCO2 at 18 °C. In general, the steady state cell density and particulate organic carbon (POC) production increased with pCO2, yielding significantly higher concentrations in cultures grown at 900 µatm pCO2 compared to 300 and 550 µatm pCO2. At 900 µatm pCO2, elevation of temperature as expected for a greenhouse ocean, further increased cell densities and POC concentrations. In contrast to POC concentration, C-quotas (pmol C cell-1) were similar at D = 0.3 d-1 in all cultures. At D = 0.1 d-1, a reduction of C-quotas by up to 15% was observed in the 900 µatm pCO2 at 18 °C culture. As a result of growth rate reduction, POC:PON:POP ratios deviated strongly from the Redfield ratio, primarily due to an increase in POC. Ratios of particulate inorganic and organic carbon (PIC:POC) ranged from 0.14 to 0.18 at D = 0.3 d-1, and from 0.11 to 0.17 at D = 0.1 d-1, with variations primarily induced by the changes in POC. At D = 0.1 d-1, cell volume was reduced by up to 22% in cultures grown at 900 µatm pCO2. Our results indicate that changes in pCO2, temperature and phosphorus supply affect cell density, POC concentration and size of E. huxleyi (PML B92/11) to varying degrees, and will likely impact bloom development as well as biogeochemical cycling in a greenhouse ocean.

Description: Coccolithophores are important calcifying phytoplankton predicted to be impacted by changes in ocean carbonate chemistry caused by the absorption of anthropogenic CO2. However, it is difficult to disentangle the effects of the simultaneously changing carbonate system parameters (CO2, bicarbonate, carbonate and protons) on the physiological responses to elevated CO2. Here, we adopted a multifactorial approach at constant pH or CO2 whilst varying dissolved inorganic carbon (DIC) to determine physiological and transcriptional responses to individual carbonate system parameters. We show that Emiliania huxleyi is sensitive to low CO2 (growth and photosynthesis) and low bicarbonate (calcification) as well as low pH beyond a limited tolerance range, but is much less sensitive to elevated CO2 and bicarbonate. Multiple up-regulated genes at low DIC bear the hallmarks of a carbon-concentrating mechanism (CCM) that is responsive to CO2 and bicarbonate but not to pH. Emiliania huxleyi appears to have evolved mechanisms to respond to limiting rather than elevated CO2. Calcification does not function as a CCM, but is inhibited at low DIC to allow the redistribution of DIC from calcification to photosynthesis. The presented data provides a significant step in understanding how E. huxleyi will respond to changing carbonate chemistry at a cellular level

Description: Global warming may exacerbate inorganic nutrient limitation, including phosphorus (P), in the surface-waters of tropical oceans that are home to extensive blooms of the marine diazotrophic cyanobacterium, Trichodesmium. We examined the combined effects of P limitation and pCO2, forecast under ocean acidification scenarios, on Trichodesmium erythraeum IMS101 cultures. We measured nitrogen acquisition, glutamine synthetase activity, C uptake rates, intracellular Adenosine Triphosphate (ATP) concentration and the pool sizes of related key proteins. Here, we present data supporting the idea that cellular energy re-allocation enables the higher growth and N2 fixation rates detected in Trichodesmium cultured under high pCO2. This is reflected in altered protein abundance and metabolic pools. Also modified are particulate organic carbon and nitrogen production rates, enzymatic activities, and cellular ATP concentrations. We suggest that adjusting these cellular pathways to changing environmental conditions enables Trichodesmium to compensate for low P availability and to thrive in acidified oceans. Moreover, elevated pCO2 could provide Trichodesmium with a competitive dominance that would extend its niche, particularly in P-limited regions of the tropical and subtropical oceans.

Description: Marine calcareous sediments provide a fundamental basis for palaeoceanographic studies aiming to reconstruct past oceanic conditions and understand key biogeochemical element cycles. Calcifying unicellular phytoplankton (coccolithophores) are a major contributor to both carbon and calcium cycling by photosynthesis and the production of calcite (coccoliths) in the euphotic zone, and the subsequent long-term deposition and burial into marine sediments. Here we present data from controlled laboratory experiments on four coccolithophore species and elucidate the relation between the divalent cation (Sr, Mg and Ca) partitioning in coccoliths and cellular physiology (growth, calcification and photosynthesis). Coccolithophores were cultured under different seawater temperature and carbonate chemistry conditions. The partition coefficient of strontium (DSr) was positively correlated with both carbon dioxide (pCO2) and temperature but displayed no coherent relation to particulate organic and inorganic carbon production rates. Furthermore, DSr correlated positively with cellular growth rates when driven by temperature but no correlation was present when changes in growth rates were pCO2-induced. Our results demonstrate the complex interaction between environmental forcing and physiological control on the strontium partitioning in coccolithophore calcite and challenge interpretations of the coccolith Sr / Ca ratio from high-pCO2 environments (e.g. Palaeocene-Eocene thermal maximum). The partition coefficient of magnesium (DMg) displayed species-specific differences and elevated values under nutrient limitation. No conclusive correlation between coccolith DMg and temperature was observed but pCO2 induced a rising trend in coccolith DMg. Interestingly, the best correlation was found between coccolith DMg and chlorophyll a production, suggesting that chlorophyll a and calcite associated Mg originate from the same intracellular pool. These and previous findings indicate that Mg is transported into the cell and to the site of calcification via different pathways than Ca and Sr. Consequently, the coccolith Mg / Ca ratio should be decoupled from the seawater Mg / Ca ratio. This study gives an extended insight into the driving factors influencing the coccolith Mg / Ca ratio and should be considered for future palaeoproxy calibrations.

Description: In tropical eastern Africa, vegetation distribution is largely controlled by regional hydrology, which has varied over the past 20 000 years. Therefore, accurate reconstructions of past vegetation and hydrological changes are crucial for a better understanding of climate variability in the tropical southeastern African region. We present high-resolution pollen records from a marine sediment core recovered offshore of the Rufiji River delta. Our data document significant shifts in pollen assemblages during the last deglaciation, identifying, through changes in both upland and lowland vegetation, specific responses of plant communities to atmospheric (precipitation) and coastal (coastal dynamics and sea-level changes) alterations. Specifically, arid conditions reflected by a maximum pollen representation of dry and open vegetation occurred during the Northern Hemisphere cold Heinrich event 1 (H1), suggesting that the expansion of drier upland vegetation was synchronous with cold Northern Hemisphere conditions. This arid period is followed by an interval in which forest and humid woodlands expanded, indicating a hydrologic shift towards more humid conditions. Droughts during H1 and the shift to humid conditions around 14.8 kyr BP in the uplands are consistent with latitudinal shifts of the intertropical convergence zone (ITCZ) driven by high-latitude Northern Hemisphere climatic fluctuations. Additionally, our results show that the lowland vegetation, consisting of well-developed salt marshes and mangroves in a successional pattern typical for vegetation occurring in intertidal habitats, has responded mainly to local coastal dynamics related to marine inundation frequencies and soil salinity in the Rufiji Delta as well as to the local moisture availability. Lowland vegetation shows a substantial expansion of mangrove trees after ~ 14.8 kyr BP, suggesting an increased moisture availability and river runoff in the coastal area. The results of this study highlight the decoupled climatic and environmental processes to which the vegetation in the uplands and the Rufiji Delta has responded during the last deglaciation.

Description: Increasing atmospheric CO2 concentrations are expected to impact pelagic ecosystem functioning in the near future by driving ocean warming and acidification. While numerous studies have investigated impacts of rising temperature and seawater acidification on planktonic organisms separately, little is presently known on their combined effects. To test for possible synergistic effects we exposed two coccolithophore species, Emiliania huxleyi and Gephyrocapsa oceanica, to a CO2 gradient ranging from ~0.5-250 µmol/kg (i.e. ~20-6000 µatm pCO2) at three different temperatures (i.e. 10, 15, 20°C for E. huxleyi and 15, 20, 25°C for G. oceanica). Both species showed CO2-dependent optimum-curve responses for growth, photosynthesis and calcification rates at all temperatures. Increased temperature generally enhanced growth and production rates and modified sensitivities of metabolic processes to increasing CO2. CO2 optimum concentrations for growth, calcification, and organic carbon fixation rates were only marginally influenced from low to intermediate temperatures. However, there was a clear optimum shift towards higher CO2 concentrations from intermediate to high temperatures in both species. Our results demonstrate that the CO2 concentration where optimum growth, calcification and carbon fixation rates occur is modulated by temperature. Thus, the response of a coccolithophore strain to ocean acidification at a given temperature can be negative, neutral or positive depending on that strain's temperature optimum. This emphasizes that the cellular responses of coccolithophores to ocean acidification can only be judged accurately when interpreted in the proper eco-physiological context of a given strain or species. Addressing the synergistic effects of changing carbonate chemistry and temperature is an essential step when assessing the success of coccolithophores in the future ocean.

Description: Ocean acidification is considered a major threat to marine ecosystems and may particularly affect primary producers. Here we investigated the impact of elevated pCO2 on paralytic shellfish poisoning toxin (PST) content and composition in two strains of Alexandrium tamarense, Alex5 and Alex2. Experiments were carried out as dilute batch to keep carbonate chemistry unaltered over time. We observed only minor changes with respect to growth and elemental composition in response to elevated pCO2. For both strains, the cellular PST content, and in particular the associated cellular toxicity, was lower in the high CO2 treatments. In addition, Alex5 showed a shift in its PST composition from a nonsulfated analogue towards less toxic sulfated analogues with increasing pCO2. Transcriptomic analyses suggest that the ability of A. tamarense to maintain cellular homeostasis is predominantly regulated on the post-translational level rather than on the transcriptomic level. Furthermore, genes associated to secondary metabolite and amino acid metabolism in Alex5 were down-regulated in the high CO2 treatment, which may explain the lower PST content. Elevated pCO2 also induced up-regulation of a putative sulfotransferase sxtN homologue and a substantial down-regulation of several sulfatases. Such changes in sulfur metabolism may explain the shift in PST composition towards more sulfated analogues. All in all, our results indicate that elevated pCO2 will have minor consequences for growth and elemental composition, but may potentially reduce the cellular toxicity of A. tamarense.

Description: Diatoms can occur as single cells or as chain-forming aggregates. These two strategies affect buoyancy, predator evasion, light absorption and nutrient uptake. Adjacent cells in chains establish connections through various processes that determine strength and flexibility of the bonds, and at distinct cellular locations defining colony structure. Chain length has been found to vary with temperature and nutrient availability as well as being positively correlated with growth rate. However, the potential effect of enhanced carbon dioxide (CO2) concentrations and consequent changes in seawater carbonate chemistry on chain formation is virtually unknown. Here we report on experiments with semi-continuous cultures of the freshly isolated diatom Asterionellopsis glacialis grown under increasing CO2 levels ranging from 320 to 3400 µatm. We show that the number of cells comprising a chain, and therefore chain length, increases with rising CO2 concentrations. We also demonstrate that while cell division rate changes with CO2 concentrations, carbon, nitrogen and phosphorus cellular quotas vary proportionally, evident by unchanged organic matter ratios. Finally, beyond the optimum CO2 concentration for growth, carbon allocation changes from cellular storage to increased exudation of dissolved organic carbon. The observed structural adjustment in colony size could enable growth at high CO2 levels, since longer, spiral-shaped chains are likely to create microclimates with higher pH during the light period. Moreover increased chain length of Asterionellopsis glacialis may influence buoyancy and, consequently, affect competitive fitness as well as sinking rates. This would potentially impact the delicate balance between the microbial loop and export of organic matter, with consequences for atmospheric carbon dioxide.

Description: Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 µatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative contributions of CO2 and HCO3 (-) uptake depended strongly on the assay pH. At pH values =〈 8.1, cells preferentially used CO2 (〉= 90 % CO2), whereas at pH values 〉= 8.3, cells progressively increased the fraction of HCO3 (-) uptake (~45 % CO2 at pH 8.7 in diploid cells; ~55 % CO2 at pH 8.5 in haploid cells). In contrast to the short-term effect of the assay pH, the pCO2 acclimation history had no significant effect on the carbon uptake behavior. A numerical sensitivity study confirmed that the pH-modification in the (14)C disequilibrium method yields reliable results, provided that model parameters (e.g., pH, temperature) are kept within typical measurement uncertainties. Our results demonstrate a high plasticity of E. huxleyi to rapidly adjust carbon acquisition to the external carbon supply and/or pH, and provide an explanation for the paradoxical observation of high CO2 sensitivity despite the apparently high HCO3 (-) usage seen in previous studies.

Description: We investigated the responses of the ecologically dominant Antarctic phytoplankton species Phaeocystis antarctica (a prymnesiophyte) and Fragilariopsis cylindrus (a diatom) to a clustered matrix of three global change variables (CO2, mixed-layer depth, and temperature) under both iron (Fe)-replete and Fe-limited conditions based roughly on the Intergovernmental Panel on Climate Change (IPCC) A2 scenario: (1) Current conditions, 39 Pa (380 ppmv) CO2, 50 µmol photons/m**2/s light, and 2°C; (2) Year 2060, 61 Pa (600 ppmv) CO2, 100 µmol photons/m**2/s light, and 4°C; (3) Year 2100, 81 Pa (800 ppmv) CO2, 150 µmol photons/m**2/s light, and 6°C. The combined interactive effects of these global change variables and changing Fe availability on growth, primary production, and cell morphology are species specific. A competition experiment suggested that future conditions could lead to a shift away from P. antarctica and toward diatoms such as F. cylindrus. Along with decreases in diatom cell size and shifts from prymnesiophyte colonies to single cells under the future scenario, this could potentially lead to decreased carbon export to the deep ocean. Fe : C uptake ratios of both species increased under future conditions, suggesting phytoplankton of the Southern Ocean will increase their Fe requirements relative to carbon fixation. The interactive effects of Fe, light, CO2, and temperature on Antarctic phytoplankton need to be considered when predicting the future responses of biology and biogeochemistry in this region.

Description: Aridification is an important component of Late Neogene climate change in south-western Africa probably caused by modifications in the atmospheric circulation in relation to the initiation and intensification of the Benguela Upwelling System due to globally steepening of the meridional pressure gradient. Intensification of the meridional pressure gradient influenced the climate intensively which had then an impact on the vegetation. However, vegetation changes of south-western Africa from the Miocene to Pliocene have not yet been reported and only indirectly investigated by sedimentological data. Here, we present a pollen record of marine ODP Site 1081 retrieved 160 km offshore Namibia covering the time between 9 and 2.7 Ma. Using an endmember unmixing model we distinguished three vegetation phases: a relative wet phase, during the Tortonian, showing higher representations of Cyperaceae, a transition phase during the Messinian, when especially grasses expanded, and a dry one covering the Pliocene with a strong representation of desert and semi-desert plants. The three phases indicate ongoing aridification probably caused by intensified meridional pressure gradients. Additionally, aquatic vegetation indicators appear in our pollen record from around 5 Ma on, which we attribute to a relocation of the lower course of the Cunene River to its modern outlet in the Atlantic Ocean. Redirection of the Cunene River toward the Atlantic would have deprived the palaeolake Cunene of an important source of fresh-water ultimately resulting in desiccation of the lake and the formation of the Etosha Pan.