ALBERT

Description: Some of the basic assumptions implied in the theory of limiting similarity of coexisting competitors were investigated experimentally in the case of three congeneric, deposit feeding snails. The species show character displacement with respect to size when coexisting. In experimental containers with a natural substrate, interspecific, exploitative competition between snails of the same size range is as intense as intraspecific competition. Diatoms of a given size range, which constitute the most important food, show a "logistic" growth response to grazing, and individual growth of the snails is linearly related to diatom density. The previous observation that the snails show size dependent selection for ingested particle sizes is extended to show that this mechanism leads to a real resource partitioning between snails of different sizes. Size frequency distribution of diatoms in the sediment is a function of the sizes of grazing snails. Size selection of ingested sand grains may also be significant for resource partitioning since the migration rate of the attached microflora between sand grains seems to be slow relative to its growth on the individual sand grains.

Description: The causes of the growth and collapse of the large Pleistocene ice sheets is a topic of intense scientific debate. The amount of new data and ideas has been prodigious during the last ten years. This review concentrates on the shifting patterns of glacial advance and shrinkage during the last Glaciation. We also examine reconstructions of conditions during the maximum of this Glaciation about 18,000 BP, and the mechanisms that might have caused the rapid collapse of many of the world's ice sheets between 18,000 and 8000 BP. Our paper focuses on the North Atlantic sector because it is there that the major Pleistocene ice sheets grew, developed, and retreated.

Description: In brackish water the variety of marine and freshwater parasite species is considerably reduced. The distribution in brackish water of most marine endoparasites is restricted by the salinity tolerance of their hosts, most of the parasite species are more tolerant than their hosts. The influence of salinity and temperature on nine species has been examined; first stage larvae of Contracaecum aduncum develop in 0-32‰ salinity; Cryptocotyle lingua proved to be infective at salinities down to 4‰. The greatest resistance was found in Anisakis larvae from herring Clupea harengus, which survived for more than half a year. Parasites in the fish intestines appear to be unaffected by changing water salinities, as the osmolarity in the intestines stays nearly constant. Marine ectoparasites (Acanthochondria depressa, Lepeophtheirus pectoralis) survive about three times longer than freshwater species (Piscicola geometra, Argulus foliaceus) when salinity is 16‰. High temperature increases the effects of adverse salinities on parasites. There is evidence that none of these ecto-parasitic species can develop within the range of 7-20‰ salinity.

Description: The effects of hydrostatic pressure and dissolved oxygen concentration on oxygen consumption rates were examined in the mesopelagic, vertically migrating squid Histioteuthis heteropsis from southern California offshore waters. Elevated hydrostatic pressure (to 136 atm) had no significant effects on oxygen consumption rates at 5°C. Lox oxygen concentrations (〈0.5 ml O2 liter -1) depressed rates of oxygen consumption. These findings suggest that biosis may be necessary to supply the total nergy needs of this species at daytime depths in the oxygen minumum layer off southern California.

Description: Intense bottom-ice algal blooms, often dominated by diatoms, are an important source of food for grazers, organic matter for export during sea ice melt, and dissolved organic carbon. Sea-ice diatoms have a number of adaptations, including accumulation of compatible solutes, that allows them to inhabit this highly variable environment characterized by extremes in temperature, salinity, and light. In addition to protecting them from extreme conditions, these compounds present a labile, nutrient-rich source of organic matter, and include precursors to climate active compounds (e.g., dimethyl sulfide [DMS]), which are likely regulated with environmental change. Here, intracellular concentrations of 45 metabolites were quantified in three sea-ice diatom species and were compared to two temperate diatom species, with a focus on compatible solutes and free amino acid pools. There was a large diversity of metabolite concentrations between diatoms with no clear pattern identifiable for sea-ice species. Concentrations of some compatible solutes (isethionic acid, homarine) approached 1 M in the sea-ice diatoms, Fragilariopsis cylindrus and Navicula cf. perminuta, but not in the larger sea-ice diatom, Nitzschia lecointei or in the temperate diatom species. The differential use of compatible solutes in sea-ice diatoms suggests different adaptive strategies and highlights which small organic compounds may be important in polar biogeochemical cycles.

Description: This report summarizes the first WP6 consultation on ocean liming, which focused on the life-cycle assessment (LCA) of lime produced within existing industrial processes for carbon dioxide removal through ocean alkalinity enhancement (see Deliverable 6.2 for further details on the LCA).

Description: This document is the first of three periodic reports on available data.

Description: This report provides an overview on the cooperation activities with relevant EU projects and other initiatives on negative emission technologies in the first phase of the OceanNETs project (01.07.2020 – 31.12.2021).

Description: This report provides an overview of OceanNETs engagement with relevant stakeholders and the OceanNETs stakeholder reference group in the first 18 month of the project (01.07.2020 – 31.12.2021).

Description: Ocean Alkalinization deliberately modifies the chemistry of the surface ocean to enhance the uptake of atmospheric CO2. Here we quantify, using idealized Earth system model (ESM) simulations, changes in carbon cycle feedbacks and in the seasonal cycle of the surface ocean carbonate system due to ocean alkalinization. We find that both, carbon-concentration and carbon climate feedback, are enhanced due to the increased sensitivity of the carbonate system to changes in atmospheric CO2 and changes in temperature. While the temperature effect, which decreases ocean carbon uptake, remains small in our model, the carbon concentration feedback enhances the uptake of carbon due to alkalinization by more than 20%. The seasonal cycle of air-sea CO2 fluxes is strongly enhanced due to an increased buffer capacity in an alkalinized ocean. This is independent of the seasonal cycle of pCO2, which is only slightly enhanced. The most significant change in the seasonality of the surface ocean carbonate system is an increased seasonal cycle of the aragonite saturation state, which has the potential to adversely affect ecosystem health.

Description: Research undertaken in Task 2.2 identified a range of governance challenges to ocean-based NETs related to the global ocean governance framework, e.g., linked to the transboundary nature of the ocean, potential effects of ocean-based NETs on the ocean’s condition and marine ecosystem services, as well as the many unknowns and uncertainties linked to NET-deployment. The fragmented approaches and frameworks in place to govern the global ocean further complicate comprehensive governance of these emerging technologies. This deliverable presents results from a workshop that explored how oceanbased NETs should be governed to best confront these challenges and integrate international climate targets as well as global goals for ocean and biodiversity conservation, in addition to global ambitions towards sustainable development. The workshop is part of research undertaken by Task 2.2 to assess how ocean-based NETs are addressed by the current global ocean governance framework and develop governance scenarios and recommendations to policy makers for a “good governance” of NETs in the ocean.

Description: This working paper presents first insights on lay public perceptions of marine carbon dioxide removal (CDR) approaches. In seven focus groups, three in Germany and four in Norway (including one pilot) the researchers asked members of the lay public to share their views of the ocean and the effects of climate change, four CDR approaches, as well as their reflections on responsible research and innovation (RRI) of marine CDR. The four CDR methods were ocean iron fertilization, ocean alkalinity enhancement, artificial upwelling, and blue carbon management through restoration of coastal and marine ecosystems. In addition, respondents were asked to compare the four approaches. Our findings indicate that the public will be very supportive of blue carbon management irrespective of its actual carbon sequestration potential, due in part to the perceived bad state of marine ecosystems worldwide. Participants were skeptical whether any of the CDR approaches could have relevant effect on carbon sequestration and long-term storage; they reasoned about issues such as the ability to scale up treatments in time and space, unforeseen or unforeseeable effects on ecosystems in time and space, and the role of industry in the implementation process. They argued that despite the potential availability of marine CDR, industry and the general public should stop polluting behaviors and practices. Nevertheless, the participants universally agreed that further research on all four CDR methods should be pursued to better understand effects on climate, ecosystems, local communities, and the economy.

Description: This is the stylized description of our ocean liming case study, which we are using the introduce our life-cycle assessment to stakeholders in our consultation process

Description: Any integration of extra carbon dioxide removal (CDR) via terrestrial or marine sink enhancement into climate policies requires accounting for their effectiveness in reducing atmospheric carbon concentration and translating this information into the amount of carbon credits (to be used in official and voluntary emission trading schemes). Here, we assess accounting schemes in their appropriateness of assigning carbon credits. We discuss the role of temporary carbon storage and present the various ccounting methods for carbon credit assignment. We explain how we have implemented the methods numerically and analyse carbon assignments across the different accounting schemes, using stylized, model-based ocean sink enhancement experiments.

Description: This report summarizes OceanNETs stakeholder engagement activities in the Canary Islands, prior and during the mesocosm study in ocean alkalinity enhancement carried out on the island of Gran Canaria in September-October 2021. It also presents ideas for future stakeholder engagement in the islands.

Description: Realistic alkalinization scenarios, under the global context, are proposed and examined, which can be extent to include spatial considerations and specific technical and regulatory constraints. Results provide a set of stylistic projections of total mineral (carbonate and silicate) addition, with its temporal timeframe spanning from as early as 2025 up to 2100). Among others, these estimates can be used to constrain model simulations that will be carried out in Work Package 4.

Description: We applied a 1-D plankton ecosystem-biogeochemical model to assess the impacts of ocean alkalinity enhancement (OAE) on seasonal changes in biogeochemistry and plankton dynamics. Depending on deployment scenarios, OAE should theoretically have variable effects on pH and seawater pCO2, which might in turn affect (a) plankton growth conditions and (b) the efficiency of carbon dioxide removal (CDR) via OAE. Thus, a major focus of our work is how different magnitudes and temporal frequencies of OAE might affect seasonal response patterns of net primary productivity (NPP), ecosystem functioning and biogeochemical cycling. With our study we aimed at identifying a parameterization of how magnitude and frequency of OAE affect net growth rates, so that these effects could be employed for Earth System Modell applications. So far we learned that a meaningful response parameterization has to resolve positive and negative anomalies that covary with temporal shifts. As to the intricacy of the response patterns, the derivation of such parameterization is work in progress. However, our study readily provides valuable insights to how OAE can alter plankton dynamics and biogeochemistry. Our modelling study first focuses at a local site where time series data are available (European Station for Time series in the Ocean Canary Islands ESTOC), including measurements of pH, concentrations of total alkalinity, dissolved inorganic carbon (DIC), chlorophyll-a and dissolved inorganic nitrogen (DIN). These observational data were made available by Andres Cianca (personal communication, PLOCAN, Spain), Melchor Gonzalez and Magdalena Santana Casiano (personal communication, Universidad de Las Palmas de Gran Canaria). The choice of this location was underpinned by the fact that the first OAE mesocosm experiment was conducted on the Canary Island Gran Canaria, which will facilitate synthesizing our modelling approach with experimental findings. For our simulations at the ESTOC site in the Subtropical North Atlantic we found distinct, non-linear responses of NPP to different temporal modes of alkalinity deployment. In particular, phytoplankton bloom patterns displayed pronounced temporal phase shifts and changes in their amplitude. Notably, our simulations suggest that OAE can have a slightly stimulating effect on NPP, which is however variable, depending on the magnitude of OAE and the temporal mode of alkalinity addition. Furthermore, we find that increasing alkalinity perturbations can lead to a shift in phytoplankton community composition (towards coccolithophores), which even persists after OAE has stopped. In terms of CDR, we found that a decrease in efficiency with increasing magnitude of alkalinity addition, as well as substantial differences related to the timing of addition. Altogether, our results suggest that annual OAE during the right season (i.e. physical and biological conditions), could be a reasonable compromise in terms of logistical feasibility, efficiency of CDR and side-effects on marine biota. With respect to transferability to global models, the complex, non-linear responses of biological processes to OAE identified in our simulations do not allow for simple parameterizations that can easily adapted. Dedicated future work is required to transfer the observed responses at small spatiotemporal scales to the coarser resolution of global models.

Description: Net-zero climate policies foresee deployment of atmospheric carbon dioxide removal wit geological, terrestrial, or marine carbon storage. While terrestrial and geological storage would be governed under the framework of national property rights, marine storage implies that carbon is transferred from one global common, the atmosphere, to another global common, the ocean, in particular if storage exceeds beyond coastal applications. This paper investigates the option of carbon dioxide removal (CDR) and storage in different (marine) reservoir types in an analytic climate-economy model, and derives implications for optimal mitigation efforts and CDR deployment. We show that the introduction of CDR lowers net energy input and net emissions over the entire time path. Furthermore, CDR affects the Social Cost of Carbon (SCC) via changes in total economic output but leaves the analytic structure of the SCC unchanged. In the first years after CDR becomes available the SCC is lower and in later years it is higher compared to a standard climate-economy model. Carbon dioxide emissions are first higher and then lower relative to a world without CDR. The paper provides the basis for the analysis of decentralized and potentially non-cooperative CDR policies.

Description: This study uses an existing perturbed parameter ensemble (PPE) of simulated ocean CO2 removal (CDR) to better determine sustainable pathways of ocean-based NET deployment and to provide information to constrain the design of subsequent modelling experiments. The results show that ocean alkalinity enhancement (OAE) can only help meet SDG13 (Climate Action) when other ambitious mitigation efforts are taken. This reinforces that OAE is not a substitute for emissions reduction, but could contribute to meeting our climate goals (if other factors suggest OAE is worth doing). For SDG14 (Life Below Water), the results suggest OEA can contribute to limiting or even reversing ocean acidification. Meeting many other SDG14 objectives is closely linked to also meeting SDG13. A key recommendation is therefore, that subsequent simulations in OceanNETs should only use SDG13 compatible baseline scenarios, unless there is some specific need for process understanding at higher levels of climate change. The analysis has also determined that the idealized CDR in the PPE is not suitable for determining many socio-economic constraints and the implications that these have for meeting the SDGs. Another key recommendation is therefore, that subsequent simulations within OceanNETs should use more realistic scenarios of CDR deployment.

Description: In part one of this deliverable, an ensemble of 14 CMIP6 Earth System Models is evaluated regarding their performance in simulating alkalinity and related parameters. The majority of the models and the multi-model-mean underestimate surface alkalinity compared to climatological observations. Alkalinity biases stemming from the parametrization of calcium carbonate formation and dissolution can be as big as biases stemming from model physics. In part two, we test the sensitivity of parametrizations concerning the carbonate chemistry in the FESOM2.1-REcoM3 and give recommendations for addressing alkalinity biases.

Description: This is the data management plan for the research project OceanNETs. It compiles OceanNETs research data output and describes the data handling during and after the projects duration with the aim to make OceanNETs research data FAIR – sustainably available for the scientific community. This data management plan is a living document; it will be continuously developed in close cooperation with the consortium members throughout the project duration. Version 2

Description: The potential biogeochemical and ecological impacts of ocean alkalinity enhancement were tested in a 5-weeks mesocosm experiment conducted in the subtropical, oligotrophic waters off Gran Canaria in September/October 2021. In the nine mesocosms, each with a volume of about 10 m3 inhabiting a natural plankton community, alkalinity enhancement was achieved through addition of a mix of sodium bicarbonate and sodium carbonate, simulating CO2-equilibrated alkalinization in a gradient from control up to twice the natural alkalinity. The response of the enclosed plankton community to the alkalinity addition was monitored in over 50 parameters which were sampled or measured in situ daily or every second day. In addition to the mesocosm experiment, a series of side experiments were conducted, focusing on individual aspects of mineral dissolution, secondary precipitation and biological responses at the primary producer level. This campaign, in which 47 scientists from 6 nations participated, generated the most comprehensive data set collected so far on the ecological and biogeochemical impacts of ocean alkalinity enhancement.

Description: Emissions trading systems (ETS) and markets usually do not allow for the inclusion of carbon dioxide removal (CDR) activities and if they do, removal activities are primarily restricted to afforestation. The New Zealand emission trading system (NZ ETS), for examples, integrates afforestation, and the California Low-Fuel Standard, the Quebec ETS and the Chinese ETS permit the restricted inclusion of afforestation offsets. Furthermore, the California Low-Carbon Fuel Standard System allows for the inclusion of removal via Direct Air Capture. In combination with the 45Q tax credit program, the largest incentives for CDR via Negative Emissions Technologies (NETs) are currently provided in the US. However, both do not yet allow for the inclusion of ocean-based carbon removal. Hence, we provide first a brief overview about the NZ ETS and its inclusion of afforestation, pointing out that the concept will likely not be applicable to ocean-based CDR with the potential exemption of blue carbon projects. Second, we discuss the 45Q tax credit program, the California Low-Fuel Standard System, and the California Compliance Offset Scheme. Third, we provide an overview about the company database related to ocean-based carbon removal. Fourth, we briefly look at the voluntary carbon market, providing some insights for carbon removal accounting.

Description: This deliverable synthesizes the results on public perceptions of marine CDR methods from the first two years of OceanNETs. The purpose is to inform the other work packages in OceanNETs and stakeholders about our results in a timely and brief manner about the ways members of the public view marine CDR specifically but also in the broader context of net-zero targets and climate policy. The deliverable summarises results of two studies: (1) focus groups held in Germany and Norway that covered ocean fertilization, ocean alkalinity enhancement, artificial upwelling and blue carbon management and (2) a deliberative survey in Norway that covered ocean alkalinity enhancement, macroalgae farming with BECCS or biomass sinking and land-based BECCS and enhanced weathering as terrestrial approaches for comparison. Participants in both studies emphasise the importance of reducing emissions and changing consumptions patterns. They hardly discuss the need to remove CO2 from the atmosphere to reach the Paris climate goal and the concept of negative emissions seems difficult for them to engage with. Among the methods, participants prefer ecosystem-based approaches like mangrove or seagrass restoration over other methods like alkalinity enhancement or ocean fertilization. Participants are concerned about the actual feasibility of deployment at a relevant removal scale and for a longer period. Connected to this are concerns about the controllability of the deployment and the methods’ impact, like difficulties to control negative environmental effects from biomass sinking at the seafloor. They also question the buildup of additional infrastructure or additional interventions into nature on top of already existing human interference. The opportunity to deliberate the methods increases participants’ certainty about their assessment but only slightly changes the direction of the assessment.