Biomolecular Composition of Sea Ice Microalgae and Its Influence on Marine Biogeochemical Cycling and Carbon Transfer through Polar Marine Food Webs

Microalgae growing on the underside of sea ice are key primary producers in polar marine environments. Their nutritional status, determined by their macromolecular composition, contributes to the region’s biochemistry and the unique temporal and spatial characteristics of their growth makes them essential for sustaining polar marine food webs. Here, we review the plasticity and taxonomic diversity of sea ice microalgae macromolecular composition, with a focus on how different environmental conditions influence macromolecular production and partitioning within cells and communities. The advantages and disadvantages of methodologies for assessing macromolecular composition are presented, including techniques that provide high throughput, whole macromolecular profile and/or species-specific resolution, which are particularly recommended for future studies. The directions of environmentally driven macromolecular changes are discussed, alongside anticipated consequences on nutrients supplied to the polar marine ecosystem. Given that polar regions are facing accelerated rates of environmental change, it is argued that a climate change signature will become evident in the biochemical composition of sea ice microalgal communities, highlighting the need for further research to understand the synergistic effects of multiple environmental stressors. The importance of sea ice microalgae as primary producers in polar marine ecosystems means that ongoing research into climate-change driven macromolecular phenotyping is critical to understanding the implications for the regions biochemical cycling and carbon transfer.

Disentangling the Ecological Processes Shaping the Latitudinal Pattern of Phytoplankton Communities in the Pacific Ocean

Phytoplankton are diverse and abundant as primary producers in the ocean, with diversity and community compositions varying spatially. How fundamental processes (e.g., selection, dispersal, and drift) regulate their global biogeography remains to be comprehensively explored.

Academic Air Travel Cultures: A Framework for Reducing Academic Flying

As primary producers of knowledge, academics are required to create and disseminate research. The advent of internationalisation has given great emphasis to the importance of travel as it pertains to the success of an academic career and the international standing of an institution. However, academics who are highly aeromobile—particularly researchers working in the field of climate change—are now facing allegations of hypocrisy that in some cases may compromise the efficacy of their (climate) research. The novelty of this chapter arises from the application of the cultures framework to the study of academic air travel. It highlights three key elements—cognitive norms, practices and material culture. In this chapter, the cultures framework is adopted to provide a structure within which to consider individual and institutional pathways to achieve a reduction in academic flying. By exploring the interplay of cognitive norms, practices, material culture, support and barriers, the gap between academic theory and institutional realities and practices can be systematically explored and fully elaborated. Furthermore, in doing so, academics may be encouraged to engage in critical self-reflection of the cognitive dissonance between personal intentions to reduce air miles and behaviours to the contrary.

Development of the “Applied Proteomics” Concept for Biotechnology Applications in Microalgae: Example of the Proteome Data in Nannochloropsis gaditana

Most of the marine ecosystems on our planet are still unknown. Among these ecosystems, microalgae act as a baseline due to their role as primary producers. The estimated millions of species of these microorganisms represent an almost infinite source of potentially active biocomponents offering unlimited biotechnology applications. This review considers current research in microalgae using the “omics” approach, which today is probably the most important biotechnology tool. These techniques enable us to obtain a large volume of data from a single experiment. The specific focus of this review is proteomics as a technique capable of generating a large volume of interesting information in a single proteomics assay, and particularly the concept of applied proteomics. As an example, this concept has been applied to the study of Nannochloropsis gaditana, in which proteomics data generated are transformed into information of high commercial value by identifying proteins with direct applications in the biomedical and agri-food fields, such as the protein designated UCA01 which presents antitumor activity, obtained from N. gaditana.

Nitrogen Isotope Discrepancy Between Primary Producers and Sediments in an Anoxic and Alkaline Lake

Nitrogen isotope compositions (δ15N) in sedimentary rocks are extensively used to investigate the biogeochemical nitrogen cycle through geological times. This use relies on the observation that, in modern continental platforms and anoxic basins, surface sediments faithfully record the δ15N of primary producers, assuming that it was similar in the past. Over Earth’s history, however, surface environments experienced profound changes, including the transition of ammonium-dominated to nitrate-dominated waters and the transition from exclusively microbial ecosystems to ecosystems including multicellularity, which make modern environments significantly different compared to earlier ones, potentially invalidating the fundamental assumption that surface sediments faithfully record the δ15N of primary producers. In order to improve our understanding of the nitrogen isotopic information contained in the early Earth’s sedimentary rock record, we investigate here the nitrogen isotope systematics in a microbial, nitrate free and ammonium-rich modern system, the Dziani Dzaha Lake. In this modern system, the δ15N of the reduced dissolved inorganic nitrogen (i.e., NH4+ and NH3) in the water column is close to ∼7‰ . δ15N of suspended particulate matter (SPM) show a similar average value in surface waters (i.e., where SPM is massively composed of active primary producers), but increases up to 14‰ in the deeper part of the water column during periods when it is enriched in dissolved reduced species (i.e., CH4, H2S/HS− and NH4+/NH3). Surface sediments δ15N, with values comprised between 10 and 14 ‰, seem to preferentially record these positive isotopic signatures, rather than those of active primary producers. We propose here that the observed isotopic pattern is mainly linked to the assimilation of ammonium strongly enriched in 15N by isotope exchange with ammonia under basic conditions. Although ammonium assimilation seems here to be responsible for a significant isotopic enrichment due to the basic conditions, in neutral anoxic environments inhabited by similar microbial ecosystems, this process may also significantly impact the δ15N of primary producers towards more negative values. This would have strong implications for our interpretation of the Precambrian sedimentary record as this finding challenges one the fundamental hypotheses underlying the use of sedimentary δ15N in paleo-oceanographic reconstructions, i.e. that surface sediments faithfully record the δ15N of active primary producers in the photic zone.

A biodiversity survey on the planktonic protistan grazers of the Gulf of Naples (Italy)

Plankton communities include both unicellular and multicellular organisms. An important unicellular component is represented by those protists (i.e., unicellular eukaryotes) that are non-strictly autotrophic organisms and consume bacteria and other protists. These organisms are an important link between primary producers and metazoans and are usually known as microzooplankton, protozooplankton, or mixoplankton, as many of them couple phagotrophic and photoautotrophic behaviours. Herein we report on the diversity of these organisms sampled at two sampling sites (coastal and offshore stations), at two depths (0 and 10 m), in the Gulf of Naples during the early autumn of 2020. Despite efforts to list plankton biodiversity of primary producers and metazoan grazers made in this area so far, protistan grazers are still poorly investigated and previous information date back to decades ago. Our survey identified dinoflagellates and oligotrich ciliates as the most abundant groups, while tintinnids were less quantitatively relevant. The taxonomic composition in samples investigated herein remarked that reported by previous studies, with the sole exception of the tintinnid Ascampbeliella armilla, which was never reported before. A coastal-offshore gradient in the taxonomical composition of protistan grazers was also observed, with some species more abundant within coastal waters and other better thriving in offshore ones. Surface and sub-surface communities also differed in terms of species composition, with the deeper communities in the two sites being more similar reciprocally than with communities at the surface. These differences were associated with distinct environmental conditions, such as light availability, as well with the standing feeding environment, arising potential implications in the functioning of the planktonic food web at the local scale.

Calm the farm or incite a riot? Animal activists and the news media: A public relations case study in agenda-setting and framing

The ideological differences between animal activists and primary producers are long-standing, existing long before the advent of social media with its widespread communicative capabilities. Primary producers have continued to rely on traditional media channels to promote their products. In contrast, animal activists have increasingly adopted livestreaming on social media platforms and ‘direct action’ protest tactics to garner widespread public and media attention while promoting vegetarianism/veganism, highlighting issues in animal agriculture and disrupting the notion of the ‘happy farm animal’. This paper uses a case study approach to discuss the events that unfolded when direct action animal activists came into conflict with Western Australian farmers and businesses in 2019. The conflict resulted in increased news reporting, front-page coverage from mainstream press, arrests and parliamentary law changes. This case study explores how the activists’ strategic communication activities, which included livestreaming their direct actions and other social media tactics, were portrayed by one major Australian media outlet and the farmers’ interest groups’ reactions to them.