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Optimising Multispectral Active Fluorescence to Distinguish the Photosynthetic Variability of Cyanobacteria and Algae

09.01.2023

Excerpt: The study “Optimising Multispectral Active Fluorescence to Distinguish the Photosynthetic Variability of Cyanobacteria and Algae” assesses the ability of a new active fluorometer, the LabSTAF, to diagnostically assess the physiology of freshwater cyanobacteria in a reservoir exhibiting annual blooms. Specifically, we analyse the correlation of relative cyanobacteria abundance with photosynthetic parameters derived from fluorescence light curves (FLCs) obtained using several combinations of excitation wavebands, photosystem II (PSII) excitation spectra and the emission ratio of 730 over 685 nm (Fo(730/685)) using excitation protocols with varying degrees of sensitivity to cyanobacteria and algae. FLCs using blue excitation (B) and green–orange–red (GOR) excitation wavebands capture physiology parameters of algae and cyanobacteria, respectively. The green–orange (GO) protocol, expected to have the best diagnostic propertiesRead more

Jerico: A Single Turnover Active Fluorometry sensor LabSTAF tested successfully in the oligotrophic Cretan Sea PSS

24.03.2022

Excerpt: The Cretan Sea (CS) is a subpart of the ultra-oligotrophic eastern Mediterranean Sea. In this area, major research challenges include gaining a better understanding of the trends and drivers of pH and the air-sea CO2 flux as well as improving our estimates of net primary productivity (a large part of the primary production being at depths out of satellite reach for most of the year). The JERICO-S3 Cretan Sea Pilot Supersite (PSS) aims to demonstrate the contribution of a PSS approach to study such challenges via six actions: #1 Solubility and biological pumps; #2 Improved approximations of primary production; #3 Extreme events affecting phytoplankton – AQUACOSM collaboration; #4 Upscale of regional data to a wider area; #5 New sampling strategies,Read more

The Science Behind Chelsea Technologies: Excerpts & Updates

18.01.2022

Excerpt: We probably don’t talk about the science behind Chelsea Technologies as much as we might, but academia isn’t short of research papers that reference our science, scientists and apparatus, and this small overview highlights some of the recent publications relevant to our technology. Paper: Single-Turnover Variable Chlorophyll Fluorescence as a Tool for Assessing Phytoplankton Photosynthesis and Primary Productivity: Opportunities, Caveats and Recommendations In this paper, the authors assist the existing and upcoming user community by providing an overview of current approaches and consensus recommendations for the use of ST-ChlF measurements to examine in-situ phytoplankton productivity and photo-physiology. The authors argue that a consistency of practice and adherence to basic operational and quality control standards is critical to ensuring data inter-comparability. LargeRead more

Single-Turnover Variable Chlorophyll Fluorescence as a Tool for Assessing Phytoplankton Photosynthesis and Primary Productivity

09.08.2021

Excerpt: Phytoplankton photosynthetic physiology can be investigated through single-turnover variable chlorophyll fluorescence (ST-ChlF) approaches, which carry unique potential to autonomously collect data at high spatial and temporal resolution. Over the past decades, significant progress has been made in the development and application of ST-ChlF methods in aquatic ecosystems, and in the interpretation of the resulting observations. At the same time, however, an increasing number of sensor types, sampling protocols, and data processing algorithms have created confusion and uncertainty among potential users, with a growing divergence of practice among different research groups. In this review, we assist the existing and upcoming user community by providing an overview of current approaches and consensus recommendations for the use of ST-ChlF measurements to examine in-situRead more

Improving the Accuracy of Single Turnover Active Fluorometry (STAF) for the Estimation of Phytoplankton Primary Productivity (PhytoPP)

09.03.2020

Excerpt: Photosystem II (PSII) photochemistry is the ultimate source of reducing power for phytoplankton primary productivity (PhytoPP). Single turnover active fluorometry (STAF) provides a non-intrusive method that has the potential to measure PhytoPP on much wider spatiotemporal scales than is possible with more direct methods such as 14C fixation or O2 evolved through water oxidation. LabSTAF is the Chelsea instrument using Single Turnover Active Fluorometry. Application of a STAF-derived absorption coefficient for PSII light-harvesting (aLHII) provides a method for estimating PSII photochemical flux on a unit volume basis (JVPII). Within this study, we assess potential errors in the calculation of JVPII arising from sources other than photochemically active PSII complexes (baseline fluorescence) and the package effect. Although our data show that suchRead more