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Selective laser melting (SLM) is an additive manufacturing process which enables the creation of intricate components from high performance alloys. This facilitates the design and fabrication of new cellular materials for blast and impact mitigation, where the performance is heavily influenced by geometric and material sensitivities. Design of such materials requires an understanding of the relationship between the additive manufacturing process and material properties at different length scales: from the microstructure, to geometric feature rendition, to overall dynamic performance. To date, there remain significant uncertainties about both the potential benefits and pitfalls of using additive manufacturing processes to design and optimise cellular materials for dynamic energy absorbing applications. This investigation focuses on the out-of-plane compression of stainless steel cellular materials fabricated using SLM, and makes two specific contributions. First, it demonstrates how the SLM process itself influences the characteristics of these cellular materials across a range of length scales, and in turn, how this influences the dynamic deformation. Secondly, it demonstrates how an additive manufacturing route can be used to add geometric complexity to the cell architecture, creating a versatile basis for geometry optimisation. Two design spaces are explored in this work: a conventional square honeycomb hybridised with lattice walls, and an auxetic stacked-origami geometry, manufactured and tested experimentally here for the first time. It is shown that the hybrid lattice-honeycomb geometry outperformed the benchmark metallic square honeycomb in terms of energy absorption efficiency in the intermediate impact velocity regime (approximately 100 m/s). In this regime, the collapse is dominated by dynamic buckling effects, but wave propagation effects have yet to become pronounced. By tailoring the fold angles of the stacked origami material, numerical simulations illustrated how it can be optimised for specific impact velocity regimes between 10-150 m/s. Practical design tools were then developed based on these results.

Selective laser melting (SLM) is an additive manufacturing process which enables the creation of intricate components from high performance alloys. This facilitates the design and fabrication of new cellular materials for blast and impact mitigation, where the performance is heavily influenced by geometric and material sensitivities. Design of such materials requires an understanding of the relationship between the additive manufacturing process and material properties at different length scales: from the microstructure, to geometric feature rendition, to overall dynamic performance. To date, there remain significant uncertainties about both the potential benefits and pitfalls of using additive manufacturing processes to design and optimise cellular materials for dynamic energy absorbing applications. This investigation focuses on the out-of-plane compression of stainless steel cellular materials fabricated using SLM, and makes two specific contributions. First, it demonstrates how the SLM process itself influences the characteristics of these cellular materials across a range of length scales, and in turn, how this influences the dynamic deformation. Secondly, it demonstrates how an additive manufacturing route can be used to add geometric complexity to the cell architecture, creating a versatile basis for geometry optimisation. Two design spaces are explored in this work: a conventional square honeycomb hybridised with lattice walls, and an auxetic stacked-origami geometry, manufactured and tested experimentally here for the first time. It is shown that the hybrid lattice-honeycomb geometry outperformed the benchmark metallic square honeycomb in terms of energy absorption efficiency in the intermediate impact velocity regime (approximately 100 m/s). In this regime, the collapse is dominated by dynamic buckling effects, but wave propagation effects have yet to become pronounced. By tailoring the fold angles of the stacked origami material, numerical simulations illustrated how it can be optimised for specific impact velocity regimes between 10-150 m/s. Practical design tools were then developed based on these results.

The construction industry in Europe is in transition. In the last decade, challenges related to inefficiencies in the sector, the shortage of skilled labour, and environmental concerns initiated a shift towards off-site manufacturing. In Hungary, the first examples of prefabricated residential buildings have just appeared after a 30-year-long break. At the same time, in post-socialist countries, the general attitude towards modern methods of construction is rather complex. While the Western examples of modular constructions are admired, local examples of prefabricated and standardised homes from the socialist era are neglected or criticised for their uniformity and inability to change. This thesis examines the social limits of standardisation in the Hungarian context, specifically focusing on how we can ensure that in the future, mass-manufactured buildings will be sustainable and retain their social respectability, technical qualities and economic value for a long time. It is found that standardisation does not necessarily limit creativity and can be socially sustainable, provided that it does not result in uniform constructions. Findings rely on an extensive review of the literature and real-life architectural examples, statistical results from two online surveys on preconceptions about mass-manufactured buildings, and space syntactical investigations of preferred home layouts. The findings of the project include showing that young Hungarian adults associate mass produced buildings with the loss of diversity, but they find these buildings environmentally friendly, fast to produce, progressive and fashionable. In addition, it is shown that it is possible to use small graph matching and density-based clustering to find the most suitable layouts for socially-conscious mass manufacturing. The practical outcomes of this project include an exemplar dwelling that showcases good design, a framework for discussing standardised buildings, and a Plug-in that can evaluate any new apartments created in Autodesk Revit based on the developed guidelines.

The construction industry in Europe is in transition. In the last decade, challenges related to inefficiencies in the sector, the shortage of skilled labour, and environmental concerns initiated a shift towards off-site manufacturing. In Hungary, the first examples of prefabricated residential buildings have just appeared after a 30-year-long break. At the same time, in post-socialist countries, the general attitude towards modern methods of construction is rather complex. While the Western examples of modular constructions are admired, local examples of prefabricated and standardised homes from the socialist era are neglected or criticised for their uniformity and inability to change. This thesis examines the social limits of standardisation in the Hungarian context, specifically focusing on how we can ensure that in the future, mass-manufactured buildings will be sustainable and retain their social respectability, technical qualities and economic value for a long time. It is found that standardisation does not necessarily limit creativity and can be socially sustainable, provided that it does not result in uniform constructions. Findings rely on an extensive review of the literature and real-life architectural examples, statistical results from two online surveys on preconceptions about mass-manufactured buildings, and space syntactical investigations of preferred home layouts. The findings of the project include showing that young Hungarian adults associate mass produced buildings with the loss of diversity, but they find these buildings environmentally friendly, fast to produce, progressive and fashionable. In addition, it is shown that it is possible to use small graph matching and density-based clustering to find the most suitable layouts for socially-conscious mass manufacturing. The practical outcomes of this project include an exemplar dwelling that showcases good design, a framework for discussing standardised buildings, and a Plug-in that can evaluate any new apartments created in Autodesk Revit based on the developed guidelines.

One should always be careful about giving advice: whether, when, how and what. This is especially the case if the advice is unsolicited. “Now, let me give you some advice”, is generally an unpropitious opening to a conversation. But even when advice is invited, one should tread cautiously. In this instance, I was invited by the editor-in-chief of the Christian Scholar’s Review to write this essay, which gives me some sort of mandate for what follows. And, if you are reading this, it is not unreasonable of me to think that you are looking for advice. (The title rather gives it away). But if not, then please read no further; it may benefit neither you nor me.

One should always be careful about giving advice: whether, when, how and what. This is especially the case if the advice is unsolicited. “Now, let me give you some advice”, is generally an unpropitious opening to a conversation. But even when advice is invited, one should tread cautiously. In this instance, I was invited by the editor-in-chief of the Christian Scholar’s Review to write this essay, which gives me some sort of mandate for what follows. And, if you are reading this, it is not unreasonable of me to think that you are looking for advice. (The title rather gives it away). But if not, then please read no further; it may benefit neither you nor me.

Since the first commercialization of Li-ion batteries (LIBs) in 1991, they have continued to power the society for decades. However, the ever-growing demands pose challenges to their sustainability in terms of restricted energy density, inadequate cycle life, and limited key resources. In the first part of this thesis (chapter 2), efforts made within Li batteries, with respect to sustainability in energy density, cycle life and resources are reported in three sub-chapters discussed below. Use of pure metallic Li is an important strategy for full utilization of the inherently high energy density of Li. In chapter 2.1, novel research is devoted towards quantifying major Li loss pathways for the first time. Based on the fundamental understanding gained from the quantified correlation between major Li loss forms, a rational interphase design principle for achieving highly reversible lean Li and lean electrolyte Li metal batteries (LMBs) from a holistic perspective is proposed. An inorganic-rich insoluble inner solid-electrolyte interphase (SEI) layer with high electron passivity is established, as well as the suppression of organic SEI dissolution. This work has demonstrated an ultra-low Li loss rate (mainly from Li corrosion and SEI dissolution) of 0.13 μAh cm-2 h-1 and an ultra-low SEI growth rate (mainly from Li corrosion) of 3.20 mΩ cm-2 h-1, leading to over 5000 h Li metal cycling stability at a Li utilization rate of 50%, which is very high in lean Li||Li symmetric cells. Based upon this novel molecular-level interphase design, full LIB cells have been fabricated and validated with promising results. A Li||LiFePO4 (LFP) full cell with lean Li (negative to positive, i.e., N/P ratio of 2) subject to a deep cycling rate of 0.2 C over 700 cycles running over 280 days demonstrates 90% capacity retention at an average Coulombic efficiency (CE) of 99.99%, and impressively a 480 Wh kg-1 Ah-level Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch cell with a lean N/P ratio of 1.02 and a lean electrolyte to capacity (E/C) ratio of 3 g Ah-1 achieves over 90% capacity retention over 160 cycles. In chapter 2.2, novel research with LIBs on using the high energy density of Si, second only to Li, is proposed for mitigating mechanical fracture and loss of electrical contact prevalent with a Si-based anode. A SiOx-based anode, which is capable of alleviating volumetric expansion while strengthening the electrical connectivity in the electrodes with an average CE over 99.9% in a high-loading full cell, is developed based upon a robust Si-O-C covalent bonding by molecular-level interphase wiring. Foundational-level innovative research on recovering the valuable cathodic elements from a spent LIB is devised based upon interphase designs in chapter 2.3. This novel chemically active but mechanically passive photothermal powered device consists of a solar thermal collector interphase with a porous alumina reservoir for Li, which in turn is in interphase with a thin layer of ion-sieving metal organic framework (MOF) separator fed from a solution containing Li+ and Co2+ ions from spent cathodes. A preliminary Life Cycle Assessment (LCA) is reported to validate the potential benefits from such a photothermal recycling strategy in terms of cost, energy consumption, and environmental issues. In the second part of this thesis (chapter 3), research is carried out with respect to Na-ion batteries (NIBs), as a complementary alternative to LIBs deriving benefits with respect to resource sustainability. Na is an attractive lower cost and a more widely available option than Li, and does not depend on the expensive and geographically constrained Co in the cathode. The bill of materials for a NIB is further decreased based upon the replacement of the anodic current collector from Cu to a much cheaper and lighter Al. However, SEI dissolution is much more severe in NIBs than in LIBs, leading to low Na reversibility and poor utilization of Na. The first part in chapter 3 builds a direct correlation between SEI solubility and SEI components, and for the first time quantifies that an organic SEI has 3.26 times the solubility of an inorganic SEI. A novel strategy of preforming an insoluble inorganic-rich SEI has been developed, which contributes to a high-loading hard carbon (HC)||NaMn0.33Fe0.33Ni0.33O2 full cell with 80.0% capacity retention and a record-high 99.95% average CE at 0.33 C over 900 cycles with a commercial electrolyte. In another sustainability validation with NIBs, a novel dual-salt/dual-solvent based electrolyte has been developed that is able to achieve a homogeneous and insoluble SEI. Such molecular-level interphase design contributes to 80.5% capacity retention and a record-high 99.95% average CE at 0.33 C over 1500 cycles in a HC||NaMn0.33Fe0.33Ni0.33O2 full cell. It further leads to an 87.5% state of charge (SOC) capacity in a highly challenging scenario of 4 C fast charging and 0.33 C slow discharging for a high-loading full cell, which demonstrates practical applications for challenging fast charging slow discharging scenarios such as electric vehicles (EVs). In the final part of research with NIBs, an electrolyte design principle based on a low dissolution coefficient, and a new protocol to quantify SEI dissolution have been proposed and developed for the first time. These principles have been validated in a high-loading full cell, achieving a near-unity average CE of 99.98% at 0.33 C over 1000 cycles in a HC||NaMn0.33Fe0.33Ni0.33O2 full cell. This near-unity average CE of 99.98% is not only a record value reported so far for a practical Na-ion full cell, but also satisfies the End-of-Life (EoL) model for the first time in the Na battery field, to the best of my knowledge, providing guidelines for designing stable SEIs with high Na ion reversibility. In summary, this thesis has developed and validated molecular-level interphase design principles that can help pave new ways for enhancing battery sustainability in terms of prolonged cycle life with high energy density and endurable resources.

Since the first commercialization of Li-ion batteries (LIBs) in 1991, they have continued to power the society for decades. However, the ever-growing demands pose challenges to their sustainability in terms of restricted energy density, inadequate cycle life, and limited key resources. In the first part of this thesis (chapter 2), efforts made within Li batteries, with respect to sustainability in energy density, cycle life and resources are reported in three sub-chapters discussed below. Use of pure metallic Li is an important strategy for full utilization of the inherently high energy density of Li. In chapter 2.1, novel research is devoted towards quantifying major Li loss pathways for the first time. Based on the fundamental understanding gained from the quantified correlation between major Li loss forms, a rational interphase design principle for achieving highly reversible lean Li and lean electrolyte Li metal batteries (LMBs) from a holistic perspective is proposed. An inorganic-rich insoluble inner solid-electrolyte interphase (SEI) layer with high electron passivity is established, as well as the suppression of organic SEI dissolution. This work has demonstrated an ultra-low Li loss rate (mainly from Li corrosion and SEI dissolution) of 0.13 μAh cm-2 h-1 and an ultra-low SEI growth rate (mainly from Li corrosion) of 3.20 mΩ cm-2 h-1, leading to over 5000 h Li metal cycling stability at a Li utilization rate of 50%, which is very high in lean Li||Li symmetric cells. Based upon this novel molecular-level interphase design, full LIB cells have been fabricated and validated with promising results. A Li||LiFePO4 (LFP) full cell with lean Li (negative to positive, i.e., N/P ratio of 2) subject to a deep cycling rate of 0.2 C over 700 cycles running over 280 days demonstrates 90% capacity retention at an average Coulombic efficiency (CE) of 99.99%, and impressively a 480 Wh kg-1 Ah-level Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch cell with a lean N/P ratio of 1.02 and a lean electrolyte to capacity (E/C) ratio of 3 g Ah-1 achieves over 90% capacity retention over 160 cycles. In chapter 2.2, novel research with LIBs on using the high energy density of Si, second only to Li, is proposed for mitigating mechanical fracture and loss of electrical contact prevalent with a Si-based anode. A SiOx-based anode, which is capable of alleviating volumetric expansion while strengthening the electrical connectivity in the electrodes with an average CE over 99.9% in a high-loading full cell, is developed based upon a robust Si-O-C covalent bonding by molecular-level interphase wiring. Foundational-level innovative research on recovering the valuable cathodic elements from a spent LIB is devised based upon interphase designs in chapter 2.3. This novel chemically active but mechanically passive photothermal powered device consists of a solar thermal collector interphase with a porous alumina reservoir for Li, which in turn is in interphase with a thin layer of ion-sieving metal organic framework (MOF) separator fed from a solution containing Li+ and Co2+ ions from spent cathodes. A preliminary Life Cycle Assessment (LCA) is reported to validate the potential benefits from such a photothermal recycling strategy in terms of cost, energy consumption, and environmental issues. In the second part of this thesis (chapter 3), research is carried out with respect to Na-ion batteries (NIBs), as a complementary alternative to LIBs deriving benefits with respect to resource sustainability. Na is an attractive lower cost and a more widely available option than Li, and does not depend on the expensive and geographically constrained Co in the cathode. The bill of materials for a NIB is further decreased based upon the replacement of the anodic current collector from Cu to a much cheaper and lighter Al. However, SEI dissolution is much more severe in NIBs than in LIBs, leading to low Na reversibility and poor utilization of Na. The first part in chapter 3 builds a direct correlation between SEI solubility and SEI components, and for the first time quantifies that an organic SEI has 3.26 times the solubility of an inorganic SEI. A novel strategy of preforming an insoluble inorganic-rich SEI has been developed, which contributes to a high-loading hard carbon (HC)||NaMn0.33Fe0.33Ni0.33O2 full cell with 80.0% capacity retention and a record-high 99.95% average CE at 0.33 C over 900 cycles with a commercial electrolyte. In another sustainability validation with NIBs, a novel dual-salt/dual-solvent based electrolyte has been developed that is able to achieve a homogeneous and insoluble SEI. Such molecular-level interphase design contributes to 80.5% capacity retention and a record-high 99.95% average CE at 0.33 C over 1500 cycles in a HC||NaMn0.33Fe0.33Ni0.33O2 full cell. It further leads to an 87.5% state of charge (SOC) capacity in a highly challenging scenario of 4 C fast charging and 0.33 C slow discharging for a high-loading full cell, which demonstrates practical applications for challenging fast charging slow discharging scenarios such as electric vehicles (EVs). In the final part of research with NIBs, an electrolyte design principle based on a low dissolution coefficient, and a new protocol to quantify SEI dissolution have been proposed and developed for the first time. These principles have been validated in a high-loading full cell, achieving a near-unity average CE of 99.98% at 0.33 C over 1000 cycles in a HC||NaMn0.33Fe0.33Ni0.33O2 full cell. This near-unity average CE of 99.98% is not only a record value reported so far for a practical Na-ion full cell, but also satisfies the End-of-Life (EoL) model for the first time in the Na battery field, to the best of my knowledge, providing guidelines for designing stable SEIs with high Na ion reversibility. In summary, this thesis has developed and validated molecular-level interphase design principles that can help pave new ways for enhancing battery sustainability in terms of prolonged cycle life with high energy density and endurable resources.

Climate change is impacting marine ecosystems worldwide, presenting a significant threat to biodiversity. In the Southern Ocean, organisms are facing increasing challenges due to warming, ocean acidification, reduced sea-ice cover, and freshening—the reduction in salinity caused by freshwater input. Salinity is a crucial environmental factor that affects the development, growth, reproduction, and survival of aquatic organisms. While the effects of warming, acidification and loss of sea ice cover on Antarctic marine life have been widely studied, the impact of low salinity has been under-researched. Understanding the physiological impact of environmental stressors, such as freshening, is crucial for identifying species particularly vulnerable to change. This may be particularly important for animals which are considered to have poor osmoregulatory abilities, such as echinoderms which are strictly marine with no known freshwater species. In Antarctica, echinoderms are highly abundant and conspicuous, making up around 10‰ of benthic fauna. Many are endemic to Antarctica, having adapted to the low, stable temperature environment over millions of years. Climate change will likely increase the rate and frequency of hyposalinity events in Antarctica, where vast amounts of freshwater from melting glaciers and liquid precipitation rapidly enters coastal waters, diluting seawater. Over the longer-term, climate change is also expected to cause widespread net freshening over the whole Southern Ocean. For a group of animals adapted to a thermally stable and predictable environment, and with limited abilities to function in low-salinity conditions, echinoderms are potentially vulnerable to climate-change-induced freshening in Antarctica. However, little is known about their ability to tolerate acute, short-term reductions in salinity, and even less is understood about their capacity to acclimate to sustained low-salinity conditions. This thesis set out to assess the physiological and behavioural responses of common Antarctic echinoderms to low salinity exposure over both short- and long-term timeframes, in order to evaluate their vulnerability to present and future climate-change-induced freshening. An initial global literature review of echinoderms revealed inconsistencies in experimental approaches and descriptions of short- and long-term low salinity tolerance, making comparisons between species and regional groups challenging. To address this, a methodology was developed using the temperate echinoid Echinus esculentus, which showed distinct short- and long-term metabolic responses to low salinity. Experimental data demonstrated that E. esculentus could acclimate to moderate salinity reductions, with thresholds identified between 21‰ and 26‰. This approach was then applied to Antarctic echinoderms. Acute tolerance experiments revealed species-specific responses, with unexpected variations across habitats and class. Despite this variability, phylum-wide similarities were observed in oxygen consumption, activity rates, and osmotic strategy responses. The brittle star Ophionotus victoriae showed the lowest tolerance to salinity reductions, highlighting its vulnerability to freshening, while holothurians demonstrated remarkable tolerance, in particular Echinopsolus charcoti and Cucumaria georgiana. Long-term exposure studies on the echinoid Sterechinus neumayeri and asteroid Odontaster validus indicated successful acclimation to a mid-range salinity level (29‰) within their short-term tolerance range. However, at lower salinity (24‰), although survival rates remained high, physiological and behavioural responses failed to stabilise. Significant reductions in animal mass suggested that high catabolic tissue breakdown was necessary to maintain core homeostatic functions, with prolonged exposure likely leading to mortality. To understand the mechanistic basis of low salinity acclimation, a metabolomic approach was applied to tissue samples of S. neumayeri and O. validus from the long-term experiments. These analyses provided insights into the micromolecular adaptations of cold-temperature-adapted echinoderms and their strategies for low salinity acclimation. In particular, the osmolyte profile in both species differs from temperate echinoderms and other marine invertebrates, with branched-chain amino acids (valine, leucine, and isoleucine) potentially acting as both compatible osmolytes, cryoprotectants and even an energy reserve. Overall, this thesis demonstrates that Antarctic echinoderms are capable of short-term resilience to moderate salinity reductions, with certain species showing remarkable tolerance and varying levels of acclimation capacity. This acclimation potential may provide partial resilience to predicted climate change-induced freshening. However, their long-term acclimation potential is limited, and species-specific vulnerabilities highlight the need for further research. The study also reveals that unique adaptations, such as specific osmolyte profiles, may influence their survival and ability to cope with future environmental changes. These insights highlight the need for ongoing research into Antarctic echinoderms and other marine organisms to understand their physiological limitations, which is crucial for developing targeted conservation strategies to mitigate the impacts of future freshening and environmental changes on their survival.

Climate change is impacting marine ecosystems worldwide, presenting a significant threat to biodiversity. In the Southern Ocean, organisms are facing increasing challenges due to warming, ocean acidification, reduced sea-ice cover, and freshening—the reduction in salinity caused by freshwater input. Salinity is a crucial environmental factor that affects the development, growth, reproduction, and survival of aquatic organisms. While the effects of warming, acidification and loss of sea ice cover on Antarctic marine life have been widely studied, the impact of low salinity has been under-researched. Understanding the physiological impact of environmental stressors, such as freshening, is crucial for identifying species particularly vulnerable to change. This may be particularly important for animals which are considered to have poor osmoregulatory abilities, such as echinoderms which are strictly marine with no known freshwater species. In Antarctica, echinoderms are highly abundant and conspicuous, making up around 10‰ of benthic fauna. Many are endemic to Antarctica, having adapted to the low, stable temperature environment over millions of years. Climate change will likely increase the rate and frequency of hyposalinity events in Antarctica, where vast amounts of freshwater from melting glaciers and liquid precipitation rapidly enters coastal waters, diluting seawater. Over the longer-term, climate change is also expected to cause widespread net freshening over the whole Southern Ocean. For a group of animals adapted to a thermally stable and predictable environment, and with limited abilities to function in low-salinity conditions, echinoderms are potentially vulnerable to climate-change-induced freshening in Antarctica. However, little is known about their ability to tolerate acute, short-term reductions in salinity, and even less is understood about their capacity to acclimate to sustained low-salinity conditions. This thesis set out to assess the physiological and behavioural responses of common Antarctic echinoderms to low salinity exposure over both short- and long-term timeframes, in order to evaluate their vulnerability to present and future climate-change-induced freshening. An initial global literature review of echinoderms revealed inconsistencies in experimental approaches and descriptions of short- and long-term low salinity tolerance, making comparisons between species and regional groups challenging. To address this, a methodology was developed using the temperate echinoid Echinus esculentus, which showed distinct short- and long-term metabolic responses to low salinity. Experimental data demonstrated that E. esculentus could acclimate to moderate salinity reductions, with thresholds identified between 21‰ and 26‰. This approach was then applied to Antarctic echinoderms. Acute tolerance experiments revealed species-specific responses, with unexpected variations across habitats and class. Despite this variability, phylum-wide similarities were observed in oxygen consumption, activity rates, and osmotic strategy responses. The brittle star Ophionotus victoriae showed the lowest tolerance to salinity reductions, highlighting its vulnerability to freshening, while holothurians demonstrated remarkable tolerance, in particular Echinopsolus charcoti and Cucumaria georgiana. Long-term exposure studies on the echinoid Sterechinus neumayeri and asteroid Odontaster validus indicated successful acclimation to a mid-range salinity level (29‰) within their short-term tolerance range. However, at lower salinity (24‰), although survival rates remained high, physiological and behavioural responses failed to stabilise. Significant reductions in animal mass suggested that high catabolic tissue breakdown was necessary to maintain core homeostatic functions, with prolonged exposure likely leading to mortality. To understand the mechanistic basis of low salinity acclimation, a metabolomic approach was applied to tissue samples of S. neumayeri and O. validus from the long-term experiments. These analyses provided insights into the micromolecular adaptations of cold-temperature-adapted echinoderms and their strategies for low salinity acclimation. In particular, the osmolyte profile in both species differs from temperate echinoderms and other marine invertebrates, with branched-chain amino acids (valine, leucine, and isoleucine) potentially acting as both compatible osmolytes, cryoprotectants and even an energy reserve. Overall, this thesis demonstrates that Antarctic echinoderms are capable of short-term resilience to moderate salinity reductions, with certain species showing remarkable tolerance and varying levels of acclimation capacity. This acclimation potential may provide partial resilience to predicted climate change-induced freshening. However, their long-term acclimation potential is limited, and species-specific vulnerabilities highlight the need for further research. The study also reveals that unique adaptations, such as specific osmolyte profiles, may influence their survival and ability to cope with future environmental changes. These insights highlight the need for ongoing research into Antarctic echinoderms and other marine organisms to understand their physiological limitations, which is crucial for developing targeted conservation strategies to mitigate the impacts of future freshening and environmental changes on their survival.