Artificial Upwelling in Singular and Recurring Mode: Consequences for Net Community Production and Metabolic Balance

Artificial upwelling of nutrient-rich waters and the corresponding boost in primary productivity harbor the potential to enhance marine fishery yields and strengthen the biological pump for sequestration of atmospheric CO2. There is increasing urgency to understand this technology as a “ocean-based solution” for counteracting two major challenges of the 21st century—climate change and overfishing. Yet, little is known about the actual efficacy and/or possible side effects of artificial upwelling. We conducted a large-scale off-shore mesocosm study (∼44 m3) in the oligotrophic waters of the Canary Islands to identify the community-level effects of artificial upwelling on a natural oligotrophic plankton community. Four upwelling intensities were simulated (approx. 1.5/3/5.7/10 μmol L–1 of nitrate plus phosphate and silicate) via two different upwelling modes (a singular deep-water pulse vs. recurring supply every 4 days) for 37 days. Here we present results on the response of net community production (NCP), metabolic balance and phytoplankton community composition (<250 μm). Higher upwelling intensities yielded higher cumulative NCP. Following upwelling onset, the phytoplankton community became dominated by diatoms in all treatments, but other taxa such as Coccolithophores increased later in the experiment. The magnitude of effects on the metabolic balance scaled with the amount of added deep water, leading to (i) a balanced to net-heterotrophic system in the singular and (ii) a net-autotrophic system in the recurring upwelling treatments. Accordingly, the mode in which nutrients are supplied to an oligotrophic system plays a crucial role in the ecosystem response, with recurring upwelling leading to higher long-term positive NCP than singular upwelling. These results highlight the importance of empirically measured local responses to upwelling such as community structure and metabolism, with major implications for the potential employment of artificial upwelling as an ocean-based solution to generate (primary) production.

Iron Inhibits the Translation and Activity of the Renal Epithelial Sodium Channel

Hypertension is associated with an increased renal expression and activity of the epithelial sodium channel (ENaC) and iron deficiency. Distal tubules absorb iron, causing perturbations that may influence local responses. In this observational study, we investigated the relationship between iron content and ENaC expression and activity using two cell lines and hepcidin knockout mice (a murine model of iron overload). We found that iron did not transcriptionally regulate ENaC in hepcidin knockout mice or in vitro in collecting duct cells. However, the renal tubules of hepcidin knockout mice have a lower expression of ENaC protein. ENaC activity in cultured Xenopus 2F3 cells and mpkCCD cells was inhibited by iron, which could be reversed by iron chelation. Thus, our novel findings implicate iron as a regulator of ENaC protein and its activity.

Adventure sports, risk, and human-more than human wellbeing: local responses to the challenges of the COVID-19 pandemic

The impact of, and responses to COVID-19 has dominated discussion in every area of life, and fields of academic activity. In this paper I consider some of the impacts and considerations in relation to activities that have been conceptualised as adventure sports. My intention is not to show how adventure is being done differently, rather to use the exceptional circumstances of lockdown to highlighted the multifaceted, meaningful and affective ‘everyday’ experiences of those who engage in adventure sport as part of their everyday practices. My focus is empirical research conducted in Aotearoa New Zealand during lockdowns (2020-21) focusing on coastal communities and surfing specifically. This ‘journey through lockdown’ illustrates the ways in which coastal spaces are experienced as therapeutic landscapes that can foster physical and emotional health and wellbeing from those on the shore, to full-immersion activities such as surfing, influencing people’s sense of wellbeing, collective identities, and forms of belonging. However, in the same ways that COVID has exacerbated many health inequities, it is important to be attentive to the ways in which the wellbeing benefits of coastal spaces are not available and extended to all. A range of cultural, economic, socio-demographic, and political factors contribute to a dis-connect with, or exclusion from various bluespaces. Diverse subjects and bodies access and experience bluespaces in different and unequal ways, impacting who can use blue spaces, and how it can be used. Lastly, the lockdown situation was also informing in understanding the often-romanticised nature of adventure sport participants relationship with the natural world, and more widely how this translates, or not, to broader responses to our climate emergency.

Ways of Being: Hittite Empire and Its Borderlands in Late Bronze Age Anatolia and Northern Syria

In this paper, I take identity as a characteristic of empire in its periphery, denoting the totality of: 1) the imperial strategies an empire pursues in different regions, 2) the index of empire in each region, and 3) local responses to imperialism. My case study is the Hittite Empire, which dominated parts of what is now modern Turkey and northern Syria between the seventeenth and twelfth centuries BCE, and its borderlands. To investigate the identities of the Hittite imperial system, I explore the totality of the second millennium BCE in two regions. First, I explore imperial dynamics and responses in the Ilgın Plain in inner southwestern Turkey through a study of the material collected by the Yalburt Yaylası Archaeological Landscape Research Project since 2010. Second, I explore the identity of the Hittite Empire in the city of Emar in northern Syria by a thorough study of the textual and archaeological material unearthed by the Emar Expedition. In both cases, I argue that the manifestations of the Hittite Empire were mainly conditioned by the pre-Hittite trajectories of these regions. The strategies that the administration chose to use in different borderlands sought to identify what was important locally, with the Hittite Empire integrating itself into networks that were already established as manifestations of power, instead of replacing them with new ones.

Co-option of immune effectors by the hormonal signalling system triggering metamorphosis in Drosophila melanogaster

Insect metamorphosis is triggered by the production, secretion and degradation of 20-hydroxyecdysone (ecdysone). In addition to its role in developmental regulation, increasing evidence suggests that ecdysone is involved in innate immunity processes, such as phagocytosis and the induction of antimicrobial peptide (AMP) production. AMP regulation includes systemic responses as well as local responses at surface epithelia that contact with the external environment. At pupariation, Drosophila melanogaster increases dramatically the expression of three AMP genes, drosomycin (drs), drosomycin-like 2 (drsl2) and drosomycin-like 5 (drsl5). We show that the systemic action of drs at pupariation is dependent on ecdysone signalling in the fat body and operates via the ecdysone downstream target, Broad. In parallel, ecdysone also regulates local responses, specifically through the activation of drsl2 expression in the gut. Finally, we confirm the relevance of this ecdysone dependent AMP expression for the control of bacterial load by showing that flies lacking drs expression in the fat body have higher bacterial persistence over metamorphosis. In contrast, local responses may be redundant with the systemic effect of drs since reduction of ecdysone signalling or of drsl2 expression has no measurable negative effect on bacterial load control in the pupa. Together, our data emphasize the importance of the association between ecdysone signalling and immunity using in vivo studies and establish a new role for ecdysone at pupariation, which impacts developmental success by regulating the immune system in a stage-dependent manner. We speculate that this co-option of immune effectors by the hormonal system may constitute an anticipatory mechanism to control bacterial numbers in the pupa, at the core of metamorphosis evolution.

Narratives of human trafficking: Defining policy, practice and positioning in a contested field

<p><b>This research uses narrative criminology to investigate the way the problem of human trafficking is narrated in New Zealand and international settings. It draws on accounts from professionals who are responsible for defining and responding to human trafficking, and reports, policy, and other guiding documents. The main issue driving this research is the contested nature of human trafficking. Human trafficking is a crime type that has been highly politicised resulting in shifts and changes to the way the problem of trafficking has been approached over the past 20 years, with differing trends coming to the fore and dominating trafficking practices at different times. The internationally dominant approaches which emphasise prostitution, harsh criminal responses, and border security have come under criticism for having harmful impacts for migrant workers. This research aims to understand how human trafficking is defined, what discourses are drawn on, and how international narratives may be influencing local responses with the overall aim of identifying new and less problematic ways of conceptualising human trafficking and responding to migrant exploitation.</b></p> <p>This thesis finds that different ways of narrating human trafficking are constitutive of different trafficking realities. Narratives determine the shape the problem takes, who is involved, what the causes and solutions are, who responds, and who are classed as victims and perpetrators. This research concludes that as narratives structure reality and action, in order to change how we deal with certain problems, the way the problem is narrated must also change.</p> <p>The findings of this thesis reflect current challenges in the wider international anti-trafficking field of how to avoid positioning western states and systems as outside of the problem of trafficking, issues with broadening definitions of victimhood, and questions of the role of international versus local bodies in defining problems involving migration and crime. As well as reflecting these current challenges, the findings from this research provide insights for moving forwards by proposing an alternative narrative. This counter narrative is created through drawing together components of narratives identified in this research. It avoids the issues of western exceptionalism, narrow forms of victimhood, and a focus on sex trafficking, and provides a different method for conceptualising migration, exploitation, and harm.</p>