The role of coccolithophore calcification in bioengineering their environment

Coccolithophorids are enigmatic plankton that produce calcium carbonate coccoliths, which over geological time have buried atmospheric CO2 into limestone, changing both the atmosphere and geology of the Earth. However, the role of coccoliths for the proliferation of these organisms remains unclear; suggestions include roles in anti-predation, enhanced photosynthesis and sun-screening. Here we test the hypothesis that calcification stabilizes the pH of the seawater proximate to the organisms, providing a level of acidification countering the detrimental basification that occurs during net photosynthesis. Such bioengineering provides a more stable pH environment for growth and fits the empirical evidence for changes in rates of calcification under different environmental conditions. Under this scenario, simulations suggest that the optimal production ratio of inorganic to organic particulate C (PIC : POCprod) will be lower (by approx. 20%) with ocean acidification and that overproduction of coccoliths in a future acidified ocean, where pH buffering is weaker, presents a risk to calcifying cells

DRAMA - a cybernetic approach for Plankton Digital Twins

This work describes the conceptual basis of a modelling structure to simulate the growth and activities of plankton: Dynamic Resource Assimilation Modulated Activity (DRAMA). The conceptual base of DRAMA is that the physiology and behaviour of real organisms is strongly affected by their current physiological status. For example, an organism that is well fed behaves in a different way and grows faster than one that is less well fed, or is starving. In essence, an organism functions to maximise growth and reproduction through maintaining or optimising homeostasis. This document describes the conceptual basis of the model, and provides some example model outputs. Specific application of DRAMA, with their allied explanations and equations (model code) will be published separately. The history of this work lays in a series of models developed from Flynn et al. (1997), Flynn (2001) and Flynn & Mitra (2009) which have been deployed in various studies (e.g., Fasham et al. 2006; Mitra & Flynn 2010; Flynn et al. 2012; Mitra et al. 2014, 2016). Developments of the Perfect Beast model of Flynn & Mitra (2009), targeted at describing mixoplankton (protist plankton that engage in phototrophy, osmotrophy and phagotroph - Flynn et al. 2019), such as in Leles et al. (2018, 2021) revealed the potential and also the need for developing a revised plankton model that was at once computationally more efficient, but also a model that could provide an improved description of reality. Initial attempts lead to a model that was deployed for describing commercial algal production in bioreactors (SAPPM; Flynn 2021), and was also implemented for describing protist plankton (Schneider et al. 2021). Revisions from SAPPM, with a radical overhaul of the conceptual and mathematical basis, resulted in DRAMA. The conceptual core of DRAMA has potential to provide a common platform for describing all plankton functional types; bacteria through to mesozooplankton, as well as protist plankton including mixoplankton. DRAMA is based on concepts from medium/coarse -grain systems biology, and thus lends itself for the development of digital twins of plankton

Dynamic Ecology in GNU Octave

Ekin Akoglu is a marine biologist and has expertise in ecological modelling with emphasis on trophodynamic and end-to-end ecosystem models. He carries out research on the effects of climate change, trophic competition and fisheries on fish stocks and marine ecosystems. He is currently employed as an assistant professor in the Institute of Marine Sciences at Middle East Technical University, Turkey. Kevin J Flynn is a plankton physiologist who has combined laboratory and modelling studies in his teaching and research work over 4 decades. He has a particular interest in developing simulation models to guide experiment design and to enthuse the next generation of marine scientists in plankton dynamics and ecophysiology. He has authored, or co-authored, over 175 papers, and also authored the book Dynamic Ecology upon which this work was developed. He currently works at the Plymouth Marine Laboratory, UK

Driving under the influence of an intoxicant in Ireland.

The number of specimens analysed by the MBRS has been increasing for both alcohol and drugs. Blood and urine specimens are analysed for the concentration of alcohol using Headspace Gas Chromatography. Specimens testing positive were forwarded to the State Laboratory for confirmatory analysis by either GC/MS or LC/MS. In 2000, 93 per cent of blood specimens, 91 per cent of urine specimens and 82 per cent of breath specimens were over the limit. In the same year, 57 per cent of blood specimens, 66 per cent of urine specimens and 33 per cent of breath specimens were over twice the limit. Of the 78 specimens tested for the presence of a drug or drugs, 37 were blood specimens and 41 urine specimens. Of these, 34 blood specimens and 37 urine specimens were found to be positive, while seven specimens were negative for the drug or drug classes tested (three blood and four urine specimens). There were 23 specimens found positive for one drug class and 48 for more than one drug.The number of requests for the presence of drugs in RTA blood and urine specimens is increasing annually and the high percentage of positives found in the specimens tested indicates the need for such analyses. The results showed excellent agreement for drug detection in the blood specimens analysed by the different methods, except for the cannabinoids. The number of specimens in this study is small and care must be exercised in interpreting the results

The role of coccolithophore calcification in bioengineering their environment.

Coccolithophorids are enigmatic plankton that produce calcium carbonate coccoliths, which over geological time have buried atmospheric CO2 into limestone, changing both the atmosphere and geology of the Earth. However, the role of coccoliths for the proliferation of these organisms remains unclear; suggestions include roles in anti-predation, enhanced photosynthesis and sun-screening. Here we test the hypothesis that calcification stabilizes the pH of the seawater proximate to the organisms, providing a level of acidification countering the detrimental basification that occurs during net photosynthesis. Such bioengineering provides a more stable pH environment for growth and fits the empirical evidence for changes in rates of calcification under different environmental conditions. Under this scenario, simulations suggest that the optimal production ratio of inorganic to organic particulate C (PIC : POCprod) will be lower (by approx. 20%) with ocean acidification and that overproduction of coccoliths in a future acidified ocean, where pH buffering is weaker, presents a risk to calcifying cells

Metabolic flexibility as a major predictor of spatial distribution in microbial communities

A better understand the ecology of microbes and their role in the global ecosystem could be achieved if traditional ecological theories can be applied to microbes. In ecology organisms are defined as specialists or generalists according to the breadth of their niche. Spatial distribution is often used as a proxy measure of niche breadth; generalists have broad niches and a wide spatial distribution and specialists a narrow niche and spatial distribution. Previous studies suggest that microbial distribution patterns are contrary to this idea; a microbial generalist genus (Desulfobulbus) has a limited spatial distribution while a specialist genus (Methanosaeta) has a cosmopolitan distribution. Therefore, we hypothesise that this counter-intuitive distribution within generalist and specialist microbial genera is a common microbial characteristic. Using molecular fingerprinting the distribution of four microbial genera, two generalists, Desulfobulbus and the methanogenic archaea Methanosarcina, and two specialists, Methanosaeta and the sulfate-reducing bacteria Desulfobacter were analysed in sediment samples from along a UK estuary. Detected genotypes of both generalist genera showed a distinct spatial distribution, significantly correlated with geographic distance between sites. Genotypes of both specialist genera showed no significant differential spatial distribution. These data support the hypothesis that the spatial distribution of specialist and generalist microbes does not match that seen with specialist and generalist large organisms. It may be that generalist microbes, while having a wider potential niche, are constrained, possibly by intrageneric competition, to exploit only a small part of that potential niche while specialists, with far fewer constraints to their niche, are more capable of filling their potential niche more effectively, perhaps by avoiding intrageneric competition. We suggest that these counter-intuitive distribution patterns may be a common feature of microbes in general and represent a distinct microbial principle in ecology, which is a real challenge if we are to develop a truly inclusive ecology

Acquired Phototrophy and Its Implications for Bloom Dynamics of the Teleaulax-Mesodinium-Dinophysis-Complex

The dinoflagellate Dinophysis is responsible for causing diarrhetic shellfish poisoning impacting shellfish aquaculture globally. Dinophysis species are invariably plastidic specialist non-constitutive mixoplankton (pSNCM), combining phagotrophy with acquired phototrophy. Dinophysis acquires phototrophy from another pSNCM, the ciliate Mesodinium, which in turn acquires phototrophy from cryptophytes within the Teleaulax-Plagioselmis-Geminigera clade. Despite this trophic linkage, the temporal dynamics of cryptophyte-Mesodinium-Dinophysis remain poorly understood. In this study, we present the first Teleaulax-Mesodinium-Dinophysis (TMD)-complex system dynamics model. Using this, we explored the dynamics of TMD interactions under different ecological settings. Temperature, nutrient load, mixed layer depth, and irradiance all greatly influenced the timing and magnitude of the TMD-complex interactions and, as a result, Dinophysis bloom duration and peak. Availability of Mesodinium and temporal matching of its growth to that of Dinophysis are also key biotic factors; the timing of Mesodinium availability impacts the potential of Dinophysis growth for up to 3 months. Integrating our TMD-complex model with a suitable hydrodynamic model could greatly improve our understanding of bloom formation and aid in forecasting harmful algal bloom (HAB) events. Future monitoring of Dinophysis would also be enhanced by the monitoring of the precursor prey species, Teleaulax and Mesodinium, which are rarely accorded the same effort as the HAB forming dinoflagellate