Chemotaxonomic characterization of the key genera of diatoms in the Northern Antarctic Peninsula

Abstract

Diatoms are successful in occupying a wide range of ecological niches and biomes along the global ocean. Although there is a recognized importance of diatoms for the Southern Ocean ecosystems and biogeochemical cycles, the current knowledge on their ecology and distribution along the impacted Antarctic coastal regions remains generalized at best. HPLC-CHEMTAX approaches have been extensively used to this purpose, providing valuable information about the whole phytoplankton community, even for those small-size species which are normally diffi cult to identify by light microscopy. Despite that, the chemotaxonomic method has reserved minimal focus on great diversity of types associated with diatom genera or species. Here, we show a coupling between the key genera and the corresponding chemotaxonomic subgroup type-A or type-B of diatoms via HPLC-CHEMTAX and microscopic analysis, using chlorophyll-c 1 and chlorophyll-c 3 as biomarker pigments, respectively. The results demonstrated strong correlations for nine of the fi fteen most abundant diatom genera observed along the Northern Antarctic Peninsula, from which fi ve (four) were statistically associated with chlorophyll-c 1 (chlorophyll-c 3 ). Our study highlights the importance to observe diatoms in greater detail, beyond being only one functional group, for a better understanding on their responses under a climate change scenario.

Cryptophytes: An emerging algal group in the rapidly changing Antarctic Peninsula marine environments

“…Diatoms constitute a diversified group of species along the NAP, including centric and pennate forms (Costa et al, 2022). As such, it is unlikely that shallower mixing layers could be preventing all diatom species to grow and, consequently, accumulating biomass, especially those of pennate shapes that show high plasticity to cope with excess light (Petrou et al, 2016).…”

Drivers of Marine CO2‐Carbonate Chemistry in the Northern Antarctic Peninsula

“…Also, intense primary production in the north‐western Weddell Sea continental shelf (Detoni et al., 2015; Mendes et al., 2012) likely promotes high dissolved organic carbon concentrations in the deep basins of Bransfield Strait (Avelina et al., 2020). Furthermore, regions related to islands and coastal zones in the strait are also associated with high organic carbon concentrations, such as Deception Island and Admiralty Bay (Costa et al., 2022; Doval et al., 2002).…”

La comunidad fitoplanctónica en zonas costeras previamente inexploradas del oeste de la Península Antártica (63° – 67° S)

“…El enfoque quimiotaxonómico basado en la Cromatografía Líquida de Alta Eficiencia, también conocido como HPLC por sus siglas en inglés, y el software CHEMTAX se ha utilizado ampliamente en los estudios del fitoplancton a lo largo de la PA (Rodriguez et al 2002;Kozlowski et al 2011;Mendes et al 2012Mendes et al , 2013Mendes et al , 2018aPan et al 2020). El software utilizado se ha ido actualizando con el correr de los años y ajustando para los diversos grupos taxonómicos con nuevas relaciones entre pigmentos accesorios específicos de cada clase y la Clorofila a. Para hacer estos ajustes y obtener nuevas relaciones son imprescindibles los conteos e identificaciones al microscopio óptico (Kozlowski et al 2011;Pan et al 2020;Costa et al 2022).…”

“…Asimismo, el método HPLC-CHEMTAX brinda escasa información sobre la composición específica de los distintos grupos, por lo cual análisis recientes han intentado sumar pigmentos accesorios para poder aumentar su resolución (Costa et al 2022). En la PA, también ha habido algunos intentos de usar metodologías automatizadas (FlowCAM) pero estos trabajos tampoco han podido informar sobre la composición específica de la comunidad fitoplanctónica (García-Muñoz et al 2013;Morison y Menden-Deuer 2018;Selz et al 2018).…”