A new dinoflagellate species, Protoperidinium smithii H. Doan-Nhu, L. Phan-Tan et L. Nguyen-Ngoc sp. nov., and an emended description of Protoperidinium defectum (Balech 1965) Balech 1974 from the Ross Sea, Antarctica

On the Relationship between a Novel Prorocentrum sp. and Colonial Phaeocystis antarctica under Iron and Vitamin B12 Limitation: Ecological Implications for Antarctic Waters

“…In addition, a novel dinoflagellate, related to the ichthyotoxic genera Karenia and Karlodinium, discovered in the Ross Sea by [74] was closely related to the free-living, unicellular P. antarctica. Although it is not clear if kleptoplastic dinoflagellates prefer colonial or unicellular stages of P. antarctica as the plastid source [30,31], the important ecological role of mixotrophy in providing access to limiting nutrients has long been recognized [75][76][77], as it has significantly impacted prey populations in marine microbial food webs.…”

“…However, the drivers regulating these blooms remain unclear, particularly in view of recent changes in the physical and biological properties of the Ross Sea. The discovery of novel dinoflagellate species [31,78], high abundance of loricate choanoflagellates [26], and changes in the level of productivity in the Ross Sea highlight the importance of spatial assessments of phytoplankton community structure and dynamics [79], which may lead to the discovery of additional, enabling better modeling of the phytoplankton community, with important ecological implications for the Antarctic food web and biogeochemical cycles in the Southern Ocean [80].…”

“…The first detailed research on Southern Ocean dinoflagellates was started by Balech [27] who identified different species in 1976 [28], and the group has been later reported during both spring and summer in the Ross Sea (http://www.bco-dmo.org/dataset/2732 and http://www.bco-dmo.org/dataset/3360). Some dinoflagellates described in the Ross Sea are capable of kleptoplastidy [29] and have been noted within P. antarctica colonies, although the P. antarctica morphotype that serves as the plastid source remains unknown [30,31]. Drivers regulating phytoplankton blooms in the Ross Sea have received significant attention in the last decade, which has led to several studies being conducted and new discoveries being made, including a new species of dinoflagellates belonging to the genus Protoperidinium that was recently described by Phan-Tan [31] in the south-central Ross Sea.…”

“…Some dinoflagellates described in the Ross Sea are capable of kleptoplastidy [29] and have been noted within P. antarctica colonies, although the P. antarctica morphotype that serves as the plastid source remains unknown [30,31]. Drivers regulating phytoplankton blooms in the Ross Sea have received significant attention in the last decade, which has led to several studies being conducted and new discoveries being made, including a new species of dinoflagellates belonging to the genus Protoperidinium that was recently described by Phan-Tan [31] in the south-central Ross Sea. Because the dominance of different functional groups channels the energy flow through different trophic patterns, thus, differentially influencing the export of carbon aggregates out of the photic zone [32,33], the discovery of new phytoplankton species could reflect the changes occurring in the Antarctic waters, inciting the re-evaluation of the role of minor functional groups within the phytoplankton community of the Ross Sea.…”

Bacterioplankton Diversity and Distribution in Relation to Phytoplankton Community Structure in the Ross Sea surface waters

“…Phytoplankton blooms here have been well studied, with the dominance of diatoms and haptophytes presenting different temporal and spatial patterns (Smith et al, 2014;Mangoni et al, 2017). In the last years, however, changes in phytoplankton blooms and dynamics that contrast the classical Antarctic paradigm have been observed (DiTullio et al, 2000;Phan-Tan et al, 2018;Mangoni et al, 2019;Bolinesi et al, 2020b), suggesting that phytoplankton-bacteria interactions play a key role in structuring the trophodynamics in this area (Bertrand et al, 2007(Bertrand et al, , 2015.…”