Displays

Foraminiferal Na/Ca in planktonic and benthic foraminifers is a promising new method to assess directly past seawater salinities, which complements existing approaches (e.g., paired shell Mg/Ca and δ¹⁸O, shell Ba/Ca). Recent culture and field calibration studies have shown a significant positive relationship of Na incorporation into foraminiferal calcite shells with increasing salinity [1, 2], as confirmed by our culture study of Trilobatus sacculifer [3]. However, we note that the sensitivity of Na/Ca in response to salinity changes is species-specific and regional dependent, whereas temperature could be excluded as a secondary influencing factor [2, 3, 5]. Na/Ca values vary from 1–3 mmol/mol for the same salinity within and between foraminiferal species, suggesting a dominant biological control. 

To further evaluate the robustness of Na/Ca for its application as a reliable proxy, we here examine possible secondary controls on foraminiferal Na/Ca with new data for commonly used species for paleoreconstructions (Globigerinoides elongatus, G. ruber (pink), Orbulina universa, Globigerina bulloides, Neogloboquadrina dutertrei) collected by plankton tows in the eastern tropical North Atlantic during R/V Meteor cruise M140. We performed laser ablation ICP-MS measurements on single foraminiferal shells from depth-resolved plankton tows in 20 m net-intervals from locations where salinity was essentially constant, while seawater pH and total alkalinity differed by ~0.5 and 100 µmol/kg, respectively. Plankton tow samples provide new insights into the possible effects of natural variations in carbonate system parameters on Na incorporation into calcite tests with increasing water depth. The comparison of living foraminifers to sedimentary shells gives further information about the preservation state of Na/Ca in calcite shells over time, whereas fossil shells have mostly undergone gametogenesis during their life-time, or were affected post mortem by early diagenesis (sedimentation) processes. Those foraminifers were collected from surface sediments (M65-1) located in proximity to plankton tows. Our results show that all measured species, either from plankton tows or buried in the sediment, are within the Na/Ca range of previous studies [1-5], which increases the confidence for a robust Na/Ca to salinity proxy. However, the offset of ~2-5 mmol/mol between living foraminifers collected in surface waters (0-20 m) and fossil assemblages of the same species could be related to spine loss at the end of a foraminiferal life cycle [4]. In addition, the usage of inconsistent test sizes could further influence the foraminiferal Na/Ca signal. Our results reveal significant (R = -0.97, p<0.03) decreasing Na/Ca values with increasing test sizes between 180-250 µm for G. ruber (pink, white), N. dutertei and T. sacculifer, whereas values increase again with larger size classes >355 µm (R = 0.87, p<0.02). 

[1] Wit et al. (2013) Biogeosciences 10, 6375-6387. [2] Mezger et al. (2016) Paleoceanography 31, 1562-1582. [3] Bertlich et al. (2018) Biogeosciences 15, 5991–6018.[4] Mezger et al. (2019) Biogeosciences 16, 1147-1165, 2019. [5] Allen et al. (2016) Geochim. Cosmochim. Acta 193, 197-221.

How to cite: Bertlich, J., Nürnberg, D., Hathorne, E., Siccha, M., Groeneveld, J., Meilland, J., and Kucera, M.: Reliability of foraminiferal Na/Ca as a direct paleo-salinity proxy in various planktonic species from the eastern tropical North Atlantic, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1937, https://doi.org/10.5194/egusphere-egu2020-1937, 2020.

The Labrador Sea is important for the modern global thermohaline circulation system through the formation of intermediate Labrador Sea Water (LSW) that has been hypothesized to stabilize the modern mode of North Atlantic deep-water circulation. The rate of LSW formation is controlled by the amount of winter heat loss to the atmosphere, the expanse of freshwater in the convection region and the inflow of saline waters from the Atlantic. The Labrador Sea, today, receives freshwater through the East and West Greenland Currents (EGC, WGC) and the Labrador Current (LC). Several studies have suggested the WGC to be the main supplier of freshwater to the Labrador Sea, but the role of the southward flowing LC in Labrador Sea convection is still debated. At the same time, many paleoceanographic reconstructions from the Labrador Shelf focussed on late Deglacial to early Holocene meltwater run-off from the Laurentide Ice Sheet (LIS), whereas little information exists about LC variability since the final melting of the LIS about 7,000 years ago. In order to enable better assessment of the role of the LC in deep-water formation and its importance for Holocene climate variability in Atlantic Canada, this study presents high-resolution middle to late Holocene records of sea surface and bottom water temperatures, freshening and sea ice cover on the Labrador Shelf during the last 6,000 years. Our records reveal that the LC underwent three major oceanographic phases from the Mid- to Late Holocene. From 6.2 to 5.6 ka BP, the LC experienced a cold episode that was followed by warmer conditions between 5.6 and 2.1 ka BP, possibly associated with the late Holocene Thermal Maximum. Although surface waters on the Labrador Shelf cooled gradually after 3 ka BP in response to the Neoglaciation, Labrador Shelf subsurface/bottom waters show a shift to warmer temperatures after 2.1 ka BP. Although such an inverse stratification by cooling of surface and warming of subsurface waters on the Labrador Shelf would suggest a diminished convection during the last two millennia compared to the mid-Holocene, it remains difficult to assess whether hydrographic conditions in the LC have had a significant impact on Labrador Sea deep-water formation. This study was conducted within the HOSST research school with the aim to improve our understanding of the critical processes involved in the North Altantic thermohaline circulation, which is particularly important in light of current climate change. 

How to cite: Lochte, A., Schneider, R., Repschläger, J., Kienast, M., Blanz, T., Garbe-Schönberg, D., and Andersen, N.: Surface and subsurface Labrador Shelf water mass conditions during the last 6,000 years , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3160, https://doi.org/10.5194/egusphere-egu2020-3160, 2020.

Remediation of climate change induced by anthropogenic emissions of greenhouse gasses and
it precursors is the main focus today. However, less known is that the environment may also
be subjected to relatively fast geological dynamical phenomena such as the isostatic uplift of
Fennoscandia, parts of Canada and northwestern Russia. This uplift affects the archipelago
along the coast of southwestern Finland and Sweden and causes the relocation of human
activities.
In this study we investigate the on-ground observed regression of the Gulf of Bothnia on the
coasts of southwestern Finland and its implications on the country-side activities in the
framework of the eco-development paradigm. We focus our study on the neighbourhood of
the Nordsund peninsula (60°40’30”N, 21°37’14”E) between Keikvesi and Katavakarinselkä,
representative for the whole Finnish archipelago with an average local isostatic uplift of 9 mm
per year (5 mm in the South and 14 mm in the Merenkurkku area. The Nordsund peninsula
contains a former bay of the Bothnia Sea, called Mustalahti, which is reduced to a lake since
the direct way out of inner land precipitation to the open sea disappeared in the 1980s.
We show that remotely sensed data on vegetation and surface wetness confirms this fast sea
regression and the silting-up of the nearby lakes that drain precipitation to the Gulf. The
changing of the Mustalahti over time and its vegetation is expressed in terms of Normalized
Difference Vegetation Index (NDVI) and the Normalized Difference Wetness Index (NDWI),
derived from Landsat 7 data for May, 12 th 2000 and for Landsat 8 for April, 23 rd 2019
characterized by a 30 m x 30 m pixel resolution. We discuss this changing coastline in the
framework of the Eco-Development paradigm which may rebalance nature, environment,
humans and culture. This paradigm is a valid alternative against the past and present-day
socio-economical dominant approach that contributed to the accelerated change of the Earth’s
climate.

How to cite: Verstraeten, G. J. M. and Verstraeten, W. W.: Eco-development response to climate change and the isostatic uplift of southwestern Finland: Case study of the Nordsund area, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3541, https://doi.org/10.5194/egusphere-egu2020-3541, 2020.

How to cite: Bryndum-Buchholz, A., Corbalan, A., and Shajahan, N.: Finding solutions in an interdisciplinary environment , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4263, https://doi.org/10.5194/egusphere-egu2020-4263, 2020.

Understanding how changes in limiting nutrient availability affect life in the oceans requires interdisciplinary efforts. Here we illustrate this with an example of silicon, one of the most common elements on land which bioavailable form, silicic acid (Si(OH)₄), is a limiting nutrient for silicifying primary producers, such as diatoms.

 Silicic acid concentrations in the pelagic polar and subpolar North Atlantic have declined by 1-2 μM during spring pre-bloom conditions over the past 25 years. Many coastal areas of the North Atlantic region also face decreased relative availability of silicon due to increased riverine supply of nitrogen and phosphorus and stable or declining loads of silicon. Both declining silicic acid concentrations and declining silicon to nitrogen (Si:N) ratios limit the growth of diatoms, which are major primary producers contributing up to a quarter of global primary production.

To assess the effects of declining silicon availability on phytoplankton communities we conducted a mesocosm experiment manipulating Si:N ratios and copepod grazing pressure on phytoplankton communities from the Baltic Sea. Declining Si:N ratio affected not only diatom abundance and relative biomass but also their species composition and overall plankton diversity. Our results illustrate the importance of silicon in structuring community composition at the base of temperate marine food webs. Changes in silicic acid concentrations and Si:N ratios, therefore, may have far-reaching consequences on oceanic primary production and planktonic food webs.

The decline in silicon concentrations in polar and subpolar North Atlantic waters is attributed to natural multi-decadal variability but is likely amplified by reduced ocean mixing due to increased water temperatures, illustrating the need of international efforts to curb global climate change. The decline in Si:N ratios in coastal oceans also highlights the need for further reduction of nutrient pollution and improved river basin management. This may require interdisciplinary and international approaches to manage anthropogenic perturbations of the silicon cycle.

How to cite: Makareviciute-Fichtner, K., Matthiessen, B., Lotze, H. K., and Sommer, U.: Declining silica availability – a challenge in the North Atlantic region?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4793, https://doi.org/10.5194/egusphere-egu2020-4793, 2020.

The interface between air and sea, the sea surface microlayer, covers a large part of the earth's surface and is enriched by amphiphilic organic molecules. It is a zone of very active chemistry and biology. The uppermost molecular layer directly at the air-sea interface, the so-called nanolayer, has a significant impact on wave dynamics by changing the viscoelastic properties of the interface and hence modulates air-sea gas exchange.

To answer the question if nanolayer abundance can be directly correlated to primary productivity, a close collaboration between biology and physical chemistry in the spirit of fundamental surface sciences is necessary. This contribution reports a showcase example how to apply a physico-chemical laser spectroscopic tool as a valuable contribution to such an interdisciplinary field. The described non-standard experiments yield fresh insight into a complex environmental system and shed light on non-obvious relations between variable biological activity and the physical properties of the air-sea interface. In the end, this is of particular interest for the assessment of the global role of the North Atlantic to act as a sink for anthropogenic CO2 emissions. Here, strong algae blooms take place, but if they go along with an immediate or delayed nanolayer formation is largely unknown. 

From an analytical point of view, the investigation of the very thin organic layer at the air-water interface is challenging and has to rely on surface-sensitive techniques with the ability to distinguish between nanolayer and bulk water signal contributions. In this study, two complementary methods have been applied to measure both enrichment and abundance of natural sea surface films. Both laser spectroscopic Vibrational Sum Frequency Generation spectra (VSFG) and Langmuir compression isotherms yield information about the presence of surface-active compounds. Whereas the latter essentially measures surface tension changes, VSFG as a vibrational type of spectroscopy supplies additional information about the chemical nature of the interfacial molecules. Based on laboratory studies of organic nanolayer proxies, it was also possible to define a numerical index related to the surface coverage, hence simplifying the use of such measurements for other disciplines. 

More precisely, natural samples were taken at the Boknis Eck time series station (BETS) in the Baltic Sea over ten years, complemented by a comprehensive data set obtained during two consecutive research cruises in the framework of the Baltic Gas Exchange (Baltic GasEx) experiment. Enrichment of surface-active organic material in the microlayer could be confirmed by both methods, indicating the expected tight connection between micro- and nanolayer signal. In agreement with earlier preliminary data (Biogeosciences 10 (2013) 5325), a seasonal trend of nanolayer abundance has been identified that does not directly correlate with chlorophyll concentration and the approximate time of the spring algae bloom at Boknis Eck. This interesting finding implies that primary productivity is not necessarily linked with nanolayer formation and that photochemical and microbial processing of organic precursor compounds play a role for the observed seasonality. More measurements along those lines are needed, in particular for the open Atlantic Ocean, to validate these findings. 

How to cite: Lange, F.-D., Ton-Nu, N.-T., and Friedrichs, G.: Surface-Sensitive Methods for Marine Nanolayer Time-Series Studies, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4892, https://doi.org/10.5194/egusphere-egu2020-4892, 2020.

The goal of the HOSST-TOSST programme is to cultivate the next generation of advocates of the ocean. As we enter a time where all kinds of opinions are formed through the rapid exchange of unfounded information, the importance of science stays ever crucial as it could and should serve as a common ground based on factual evidence and analytical reasoning. The programme directly embedded training for scientific communication and outreach methods at the very beginning of the careers of the next generation of ocean scientists. One of the ways was through various mandatory summer schools located in marine institutes across the North Atlantic. The summer schools challenged our doctoral candidates from diverse disciplines to collaborate in teams. Each team was assigned with a mini-project, where communication and outreach were essential for their success. 

In Halifax, Canada, the project aim was to create business proposals or products that would be financially viable whilst not encumbering the already struggling ocean.
In Kiel, Germany, the end goal was to come up with proposals for Marine Protected Areas in the busiest regions of the Atlantic, all the while navigating between various stakeholders and other ocean users to come up with the best compromise.
In Mindelo, Cabo Verde, the participants, including local students, did field research and presented findings on geological processes and marine ecosystems which directly influence the lives of the residents.

The summer schools aimed to instill an awareness of how to conduct scientific communication and outreach to the general public from a multi-spectrum approach. The variety within the three projects, places and the diverse communities involved have all contributed to discussions leading to a broader view on the issues, possible solutions and scientific questions that remain open surrounding the Atlantic Ocean in all its facets.

How to cite: Meulenbroek, K., Yao, W., and Herrero, T. M.: Summer schools of the HOSST-TOSST graduate programme: a multi-sector approach towards scientific communication and outreach, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5803, https://doi.org/10.5194/egusphere-egu2020-5803, 2020.

Over the 6 years of the Transatlantic Ocean System Science and Technology program (TOSST - 2014 – 2019), graduate students participated in a variety of first class research expeditions in the North Atlantic Ocean, contributing to high quality datasets for this region and reaching a total of 380 days at-sea. These research cruises expanded from the Arctic Ocean, Labrador Sea and sub-Polar North Atlantic to the Equatorial North Atlantic, and along the African and Cabo Verdean coasts. A total of 12 long term cruises with collaboration between 18 research institutes, were conducted on board of 10 research vessels of various nationalities (Canada, Germany, Bermuda, Sweden, Ireland and USA). The range of measurements performed during these cruises, which highlights the interdisciplinary nature of the TOSST program, includes: chemical oceanography; biological oceanography; physical oceanography; marine biogeochemistry; microbiology; paleoceanography; geology; marine geophysics; and atmospheric chemistry. In this work, we will showcase the breath of research covered by TOSST graduates in the North Atlantic Ocean and provide details on the overall goals/objectives of each cruise, the teams and research vessels involved, the diverse scientific instrumentation deployed and sampling schemes. We highlight the importance of multi-disciplinary expeditions and at-sea experiences for professional as well as for personal development of early career scientists. Logistic and economic efforts are required to collect samples and to deploy instruments, therefore collaboration between disciplines, research institutes and countries (of which TOSST graduates’ research is an example) are fundamental in order to increase the quality, quantity and variety of observations in the North Atlantic Ocean.

How to cite: Arruda, R., Raimondi, L., Duplessis, P., Lehmann, N., Schulten, I., Aali, M., Wang, Y., and McCain, S.: TOSST Research Expeditions in the North Atlantic Ocean, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5811, https://doi.org/10.5194/egusphere-egu2020-5811, 2020.

The Atlantic Ocean Research Alliance was launched on the signing of the Galway Statement on Atlantic Ocean Cooperation between Canada, the European Union and the United States of America in May 2013.  A request to raise the visibility of the Atlantic Ocean was made by the trilateral Galway Statement Implementation Committee.  In answer, the #GoAtlanticBlue campaign was created and piloted in June 2019 alongside World Oceans Day as this highly visible way to raise the profile of the Atlantic Ocean in people’s everyday lives and promote a reconnection with the Atlantic Ocean.

The #GoAtlanticBlue celebrating the Atlantic Ocean and our connections to it asked people and places to don blue garments, blue face paint, blue wigs and celebrate their connections whether they be livelihoods, inspiration, health and wellbeing or sustainable actions and developments for the ocean that could be celebrated.  At night, the ask was to light up in blue and celebrate these connections.  All were asked to share on social media.  The success of this endeavour will be described and the next level of ambition will be discussed.

Following on from the June event, in August 2019 an All-Atlantic Ocean Youth Ambassador summer school was held at the special request of the Healthy Oceans & Seas Unit at the European Commission DG Research and Innovation. The All-Atlantic Ocean Youth Ambassador initiative is supported by the All-Atlantic Ocean Research Alliance under the Galway Statement on Atlantic Ocean Cooperation and the Belém Statement on Atlantic Ocean Research & innovation Cooperation. 23 Youth Ambassadors participated in this event from 15 countries along and across the Atlantic Ocean.  Three (3) campaigns types were co-created during this time under the umbrella of #MyAtlanticStory, #GoAtlanticBlue.  These campaigns as well as the All-Atlantic Ocean Youth Ambassador Forum launched in Brussels in February 2020 will be described and their success to date shown.

How to cite: Rae, M.: The #GoAtlanticBlue and the All-Atlantic Ocean Youth Ambassador Initiative to raise awareness of and promote the Atlantic Ocean, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5969, https://doi.org/10.5194/egusphere-egu2020-5969, 2020.

Submarine hydrothermal systems sustain unique ecosystems, affect global-scale biogeochemical ocean cycles, and mobilize metals from the oceanic crust to form volcanogenic massive sulfide deposits. Quantifying these processes requires linking seafloor observations to physico-chemical processes at depth and this is where numerical models of hydrothermal circulation can be particularly useful. One region where sufficient data is available to establish such a link is the East Pacific Rise (EPR) at 9°N, where vent fluid salinity and temperature have been repeatedly measured over a long time period. Here, large salinity and temperature changes of vents at the axial graben have been correlated with diking events and extrusive lava flows. Salinity changes imply the phase separation of seawater into a high-salinity brine and a low-salinity vapor phase. The intrusion of a new dike is likely to result in a characteristic salinity signal over several years: first the low salinity vapor phase rises and later the brine phase appears along with a decreasing vent temperature. These short-term salinity variations are super-imposed on the background salinity signal, which is modulated by phase separation phenomena on top of the axial magma lens. 

From these variations, numerical models can help to infer sub-surface properties and processes such as permeability, background flow rates, and brine retention as well as mobilization – if the employed model can resolve the complexity of phase separation. We here present a novel numerical model for saltwater hydrothermal systems, which uses the Finite Volume Method on unstructured meshes and the Newton-Raphson Method for solving the coupled equations. We use this new 2-D model to investigate a setup that mimics hydrothermal convection on top of the axial magma lens, which is then perturbed by a dike intrusion. In a comprehensive suite of model runs, we have identified the key controls on the time evolution of vent fluid salinity following the diking event. Based on these insights, we can reproduce time-series data from the EPR at 9°N and infer likely ranges of rock properties for the oceanic crust layer 2B. 

Our work shows how useful data integration into numerical hydrothermal models is. Unfortunately, data collection like mapping of magmatic events, continuous measurements of hydrothermal vent fluids or crustal drilling are very expensive and technically challenging. Here global and transdisciplinary collaboration would be very useful for achieving data with maximal benefit for all disciplines. Compared to the EPR the Mid-Atlantic Ridge shows a higher geological complexity, due to its lower spreading rate, and a higher diversity of vent fluid chemistry, but less continuous data is available, which hampers research using numerical models here for now. Therefore, numerical case studies at EPR serve as important validity checks for our numerical model and indicate where it has to be enhanced for quantifying processes related to hydrothermal systems at Mid-Atlantic Ridge.     

How to cite: Vehling, F., Hasenclever, J., and Rüpke, L.: Thermohaline multi-phase simulations of vent fluid salinity evolution following a diking event at East Pacific Rise, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7665, https://doi.org/10.5194/egusphere-egu2020-7665, 2020.

Unearthing transit data from several expeditions with both trained and untrained eyes started a curiosity-driven project that resulted in the discovery of the new type of intraplate volcanism. Author 1 was a first year doctoral candidate with a background in terrestrial volcano geomorphology, trained in the Philippines and was new to the field of seafloor geology. Author 2 was a fourth year doctoral candidate with a background in submarine volcanology and seafloor mapping, trained in Poland and was a seasoned seafloor mapper who served as a guide in the workings of GEOMAR and the Helmholtz Research School for Ocean System Science and Technology (HOSST) Program, as well as in submarine volcanology. Author 1 faced a challenge - learning new techniques used in the submarine environment, including how to acquire and post-process ship-based bathymetric data, and interpret seafloor structures in order to construct geological maps of the seafloor. This transition from on-land to submarine environment was the beginning of the development in understanding the processes shaping the seafloor of the North Atlantic and to focus on new scientific questions. 

Already existing ship transit data from multiple cruises were processed and anomalous high acoustic backscatter signals were found on the seafloor where such anomalies theoretically should not exist on 20Ma old oceanic crust. This coincided with later extraordinary findings collected during a more recent expedition (M139 from 2017). Observed high backscatter resembled that of fresh lava flows found along mid-ocean ridge axis. The area is an intraplate setting that do not have a known record of hotspot activity. Participation of both Authors in the expedition M139 provided an excellent environment to learn about submarine volcanology and seafloor mapping by learn-by-doing approach. Together, the authors and the whole team gathered rock samples and mapped the area in detail. Laboratory analysis and geochemical modelling concluded that the lava flows are of a different source from known intraplate volcanism compositions. The results would change the view on subducted plate composition, the geochemical budget of the Earth, and the availability of hard substrate and chemosynthetic environments for organisms in such remote regions of the seafloor.

The Helmholtz Research School for Ocean System Science and Technology (HOSST) has arranged an opportunity to bring together early career scientists of different initial backgrounds and learning cultures. It has provided a venue for candidates to go through similar experiences not only in conducting research but also in dealing with “PhD life”. It is because HOSST Research School values working in close ties on communal big picture goals for the North Atlantic Ocean and fosters a valuable support group. In this case it was a mentor-mentee relationship that helped contribute to a scientific breakthrough. This is just one example of support relationships that have developed in the HOSST graduate program.

How to cite: Herrero, T. M. and Pałgan, D.: Discovering a new type of oceanic intraplate volcanism: the experience of two PhD students - a beginner and a seasoned marine geologist, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8880, https://doi.org/10.5194/egusphere-egu2020-8880, 2020.

Understanding ocean and atmosphere dynamics in the Atlantic Ocean is the goal of the HOSST-TOSST Research school  "Transatlantic Ocean System Science and Technology“. At the heart of the project is the introduction of science work across topics of the North Atlantic Ocean System. Our goal is motivating the young researcher to consider and engage with various aspects of ocean research beyond their own special field of research. For this we have established a weekly seminar series with video system support.  It allows us to stay in contact even with an ocean between us.  Being able to stay in contact, we meet once a year in person in a joint summer school, setting up topics outside the immediate research areas and have all participants work in small groups. Co-supervision of doctoral thesis and extended research exchanges at the partner University, working with the co-supervisors research group, are fundamental for the full transatlantic research experience.

The poster and our presence will give interested persons the chance to learn from our experience how to enable a good group dynamic in the research school. Providing the basics for the best interdisciplinary research. Come and learn from our experience of establishing a dynamic research network across the Atlantic. 

How to cite: van den Bogaard, C. and Laing, K.: Trans- and interdisciplinary research - Running a Graduate Research School across the Atlantic Ocean, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9594, https://doi.org/10.5194/egusphere-egu2020-9594, 2020.

Many disciplines study the ocean and its uses from different perspectives. Recently, there has been a growing awareness about the inseparability of the social and ecological systems and that achieving sustainable use of ocean resources will require the integration of different types of knowledge and disciplines. In this presentation, we will draw from the experience of two early career interdisciplinary scientists to present examples of the role social sciences can play in achieving sustainable oceans management, how and why it should be integrated with other ocean disciplines. More specifically, we will present how a qualitative research approaches to understanding seafood sustainability governance and community/rights-based management makes an important contribution to sustainable ocean management. We conclude that to achieve ocean sustainability, which is a societal problem, we not only need numbers but also the social sciences and their narratives.

How to cite: Packer, H. and Held, M.: Numbers vs. Narratives: the importance of integrating social science perspectives in ocean sustainability research, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10056, https://doi.org/10.5194/egusphere-egu2020-10056, 2020.

The understanding of the past changes in this critical area of oceanic circulation will be beneficial to predict future climate conditions and their related socio-economic impacts. Sediment cores recovered from the western flank of the Iceland-Faroe Ridge (IFR; P457-905 and -909) provide unique archives to reconstruct changes in the Iceland-Scotland overflow water (ISOW), an important component of the Atlantic Meridional Overturning Circulation (AMOC) over the last 55-6 ka BP. We provide high-resolution records of lithogenic grain-size and XRF bulk chemistry on millennial timescales. The age models of both cores have been constrained by radiocarbon datings of planktonic foraminifera and distinct tephra layers, which include the well-known Faroe-Marine-Ash-Zones (FMAZ) II and III. Both grain-size and XRF bulk chemistry (Zr/Rb and Ti/K) reveal prominent Dansgaard-Oeschger sedimentary cycles, which reflect considerable changes in near-bottom current strength and sediment transport/deposition. The transition between cold Greenland Stadials (GSs) and warm Greenland Interstadials (GIs) occur in typical, recurring sedimentation patterns. The GIs are characterized by relatively strong bottom currents and the transport/deposition of basaltic (Ti-rich) silts from local volcanic sources resembling the modern ocean circulation pattern. In contrast, fine grained felsic (K-rich) sediments were deposited during GSs, when the ISOW was weak. In particular, the Heinrich (like) Stadials HS1 and HS2 stand out as intervals of very fine felsic sediment deposition and hence, slackened bottom currents. The bottom currents appear to progressively strengthen throughout the GIs, and sharply decline towards the GSs. This pattern contrasts with records from north of the IFR, which might be explained by a diminishing contribution of the flow cascading over the IFR. Together, these new records show strong changes in bottom current dynamics related to the Iceland-Scotland overflow, which has a strong influence on the past and modern climate of the North Atlantic Region. However, climate change is an interdisciplinary field of research. HOSST-TOSST transatlantic interdisciplinary research program provides the unique opportunity for constructive communication and collaboration among scientists with different skills filling knowledge gaps and bridging the earth sciences with social and economic disciplines. Such interdisciplinary programs at early stages in an academic career is necessary to move and encourage the new generation of the scientific community toward a tradition of broad‐scale interactions.

How to cite: Mirzaloo, M., Nürnberg, D., Kienast, M., and van der Lubbe, J.: Iceland-Faroe Ridge overflow dynamics, 55-6 ka BP, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11245, https://doi.org/10.5194/egusphere-egu2020-11245, 2020.

Increasingly, careers in ocean research are international and lie outside traditional employment sectors (academia and government). In response to a need for training that prepares the next generation of ocean scientists for a globalized, multisectoral environment, we initiated a transatlantic, multi-disciplinary graduate school which connected students and their supervisors in Halifax, Canada and Kiel, Germany. We took advantage of complementary capacities and cultures on both sides of the Atlantic to create a training program that conveyed technical and research skills in ocean science and advanced technology, and promoted the ability to manage deep sea and open ocean environments. Our goal was to provide each graduate with an international network and the ability to work effectively as an “advocate for the ocean”.

The transatlantic graduate school was supported from 2012 to 2020 with funding obtained, separately, from the Natural Sciences and Engineering Research Council’s CREATE program in Canada and the Helmholtz Association’s Graduate Research School program in Germany. The NSERC CREATE Transatlantic Ocean System Science and Technology (TOSST) was based at Dalhousie University, whereas the Helmholtz Ocean System Science and Technology (HOSST) graduate school was based at the Helmholtz Centre for Ocean Research Kiel (GEOMAR) with participation from the Christian-Albrecht University of Kiel. TOSST supported a total of 20 PhD and 3 Masters candidates. HOSST supported 24 doctoral researchers. The participants were recruited into 2 cohorts.

The participants’ disciplines ranged from marine geology to atmospheric physics and included molecular ecology, marine conservation as well as social and policy sciences, etc.. The common focus was on the Atlantic Ocean and on value-added training that addressed business skills as well as economic, regulatory, management and cultural aspects relevant to Atlantic Ocean spaces. A program of annual Summer Schools included two held in a small island developing state (Cabo Verde), with participation of African students.

TOSST-HOSST did not attempt to unify the disparate academic systems of Germany and Canada but, instead, focussed on connecting and broadening the experience of young researchers. The program sought to maximise the value of transatlantic scientific cooperation, convey broad experience and skills beyond students’ individual projects and disciplines, and create a diverse community of scholars who could work effectively together.

The presentation will highlight benefits and challenges encountered, on both sides of the Atlantic, and lessons learned during the program. Examples of lessons learned included: the value of a bilateral, cohort model for building networks of young researchers over long distances (as opposed to more distributed, multi-institutional networks); the importance of regular (effective) videoconferencing as well as (occasional) face-to-face meetings; the importance of program coordinators for overcoming barriers to international exchanges; the risk of overburdening the participants with program requirements without compensation of the academic requirements of home institutions; the need for supervisors to commit to the international aspects of the program; the value of exposure to radically different research environments (including those in developing countries).

How to cite: Wallace, D., Kienast, M., Laing, K., Townsend, B., Dullo, C., Devey, C., van den Bogaard, C., and Cabral, T.: A transatlantic, multidisciplinary graduate school focussed on the North Atlantic Ocean: rationale, challenges, lessons-learned, achievements and benefits., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12036, https://doi.org/10.5194/egusphere-egu2020-12036, 2020.

Heme b is an iron-containing cofactor in hemoproteins that participates in the fundamental processes of photosynthesis and respiration in phytoplankton. Heme b concentrations typically decline in waters with low iron concentrations but due to lack of field data, the distribution of heme b in particulate material in the ocean is poorly constrained. Within the framework of the Helmholtz Research School for Ocean System Science and Technology (HOSST) and the GEOTRACES programme, the authors compiled datasets and conducted multidisciplinary research (e.g. chemical oceanography, microbiology, biogeochemical modelling) in order to test heme b as an indicator of in situ iron-limited phytoplankton. This study was initiated in the North Atlantic Ocean and expanded to the under-sampled South Atlantic Ocean for comparison of the results considering the different phytoplankton populations. Here, we report particulate heme b distributions across the Atlantic Ocean (59.9°N to 34.6°S). Heme b concentrations in surface waters ranged from 0.10 to 33.7 pmol L^-1 (median=1.47 pmol L^-1, n=974) and were highest in regions with a high biomass. The ratio of heme b to particulate organic carbon (POC) exhibited a mean value of 0.44 μmol heme b mol^-1 POC. We identified the ratio of 0.10 µmol heme b mol^-1 POC as the cut-off between heme b replete and heme b deficient phytoplankton. By this definition, the ratio heme b relative to POC was consistently below 0.10 μmol mol^-1 in areas characterized by low Fe supply; these were the Subtropical South Atlantic gyre and the seasonally iron limited Irminger Basin. Thus, the ratio heme b relative to POC gave a reliable indication of iron limited phytoplankton communities in situ. Furthermore, the comparison of observed and modelled heme b suggested that heme b could account for between 0.17-9.1% of biogenic iron. This range was comparable to previous culturing observations for species with low heme b content and species growing in low Fe (≤0.50 nmol L^-1) or nitrate culturing media. Our large scale observations of heme b relative to organic matter suggest the impact of changes in iron supply on phytoplankton iron status.

How to cite: Louropoulou, E., Gledhill, M., Achterberg, E. P., Browning, T. J., Honey, D. J., Schmitz, R. A., and Tagliabue, A.: Heme b distributions through the Atlantic Ocean: in situ identification of iron limited phytoplankton, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-15577, https://doi.org/10.5194/egusphere-egu2020-15577, 2020.

The Marine Environmental Observation, Prediction and Response Network (MEOPAR) is an interdisciplinary Canadian Network of Centres of Excellence, connecting leading marine researchers across the country with trainees, partners and communities. MEOPAR funds research, trains Highly-Qualified Personnel, develops strategic partnerships, and works to support knowledge mobilization in marine challenges and opportunities for the benefit of the Canadian economy and society. As a Network, MEOPAR’s strength lies in our inter-sectoral connections—to researchers, partners, organizations, and Indigenous communities, all of whom have an interest in learning more about risks and opportunities in the marine environment. The Network funds research focusing on the North Atlantic, St. Lawrence, Arctic Ocean, and Salish Sea.

MEOPAR has trained over 700 Highly-Qualified Personnel (“MEOPeers”) since 2012. One in three MEOPeers are international students or researchers who have chosen to study or progress in their research careers in Canada. MEOPAR’s training program builds capacity in interdisciplinary research and 21st-century skills related to marine environmental risk and the required response and policy strategies. Training content is based on MEOPAR's four outcome areas (Ocean Observation; Forecasting and Prediction; Coastal Resilience; and Marine Operations), along with core content areas relevant to Canada’s next generation of marine professionals (Knowledge Translation and Science Communication; Interdisciplinary Research; and Career Development). To help build capacity in marine research, MEOPAR offers a suite of training initiatives to post-secondary students and early-career researchers, including a Postdoctoral Fellowship Award, Early Career Faculty grants, travel awards, workshops, International Research Internship and Visiting Scholar funding, and an Annual Training Meeting. These initiatives provide MEOPeers with value-added training opportunities they would not be able to access through their academic programs or research labs. This poster will introduce MEOPAR’s interdisciplinary and intercultural approaches to training the next generation of marine leaders in Canada. Case studies will feature MEOPeers working in the North Atlantic region who are pursuing value-added training opportunities supported by the Network. 

How to cite: Avery, L., Wallace, D., and Menafra, R.: The Marine Environmental Observation, Prediction and Response Network (MEOPAR): An Interdisciplinary, Networked Approach to Building Canada’s Marine Research Capacity , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22065, https://doi.org/10.5194/egusphere-egu2020-22065, 2020.

The HOSST and TOSST transatlantic graduate schools were conceived and designed as multidisciplinary and multicultural training opportunities. While HOSST is headquartered at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, TOSST is run out of Dalhousie University in Halifax, Canada. English being the language of science, the main language of communication in both programs is English. For most HOSST- and TOSST students, however, English is not their native tongue, but a second or even third language.

Language is a fundamental aspect of any culture; in fact, they are intertwined and mutually influence each other. A culture can only be fully understood through its corresponding language, while interacting with a different language always also illuminates the respective culture. An integral part of the HOSST- and TOSST graduate schools is the requirement that each student spends a 4-month research exchange at the sister institution. For most TOSST students, this meant immersing themselves not only into the German culture but also the German language.

To ease the transition to working and living in Germany, TOSST offered their students a German course, a proposition that was requested by the students and unanimously supported by the TOSST leadership team. Thanks to longstanding relationships with the German community in Halifax, the TOSST German course was offered through the German Heritage Language School. It so happened that the teacher was also a TOSST student. Many students accepted the offer to immerse themselves into a new language and culture ahead of their research exchange. Obviously they did not reach fluency after one or two terms, but studying German prepared them to engage with residents in everyday situations and to better understand the local culture.

Beyond these practical applications, the students appreciated an opportunity for lifelong learning outside of their field of research. Both the students and the teacher found interacting with the German language as part of their work days to foster their creativity by providing a different stimulus than their usual research efforts. The German course further provided an opportunity to build and deepen friendships among TOSST students across cultures and disciplines. The learning not only provided theoretical knowledge of the German culture, but opened up access to the sizeable German community in Halifax. A handful of students even continued with the course after their research exchange was completed as they appreciated studying the German language and culture as a skill that will serve them well beyond the TOSST graduate school.

How to cite: Held, M., Arruda, R., Chua, A., and Corbalan, A.: Learning German: The significance of language in a multicultural graduate school, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22573, https://doi.org/10.5194/egusphere-egu2020-22573, 2020.