–Shrayana Ghosh, Amity University Kolkata.
The earlier belief that phytoplankton in the artic marines are unable to grow until the snow and ice cover melts due to insufficient transmission of sunlight is now being challenged by a possible theory that suggests that marine algae may be capable of growing under extremely low irradiance also highlighting the adaption of the Artic phytoplankton to extremely low light conditions, a key to surviving the cold winters before the spring bloom.
From 2015, scientists had stationed autonomous biogeochemical (BGC) Argo floats in the Baffin Bay, an Artic Sea where the thigh ice cover lasts till July. The floats were provided with an ice resistance system and are able to measure vertical profiles of the hydrographic and bio-optical characteristics.
Results recorded by the floats during the summer of 2017-2019 showed the cycles of phytoplankton biomass based on two substitutes: one was the particle backscattering at 700nm (bbp) and second on the fluorescence of chlorophyll a. It showed a strong seasonality with rising biomass in winter and spring and a subsurface maximum in summer. Thus showing that Artic phytoplankton could grow even at extremely low light levels. The cell division rates were also observed through in-situ irradiance profiles and photosynthetic parameters. The cell division was seen to increase above zero in February with the return of the sun and increased through the months of April further indicating the observed winter net growth rates to be true.
In short, during the winter we observed slow but substantial phytoplankton growth under the Ice, probably because of photosynthesis at very low light levels, and minor breathing and grassing losses (besides possible heterotrophy). This growth may ease cell mortality during the long darkness of winter and help the seed to bloom in the spring.
Source-
P. Assmy, M. Fernández-Méndez, P. Duarte, A. Meyer, A. Randelhoff, C. J. Mundy, L. M. Olsen, H. M. Kauko, A. Bailey, M. Chierici, L. Cohen, A. P. Doulgeris, J. K. Ehn, A. Fransson, S. Gerland, H. Hop, S. R. Hudson, N. Hughes, P. Itkin, G. Johnsen, J. A. King, B. P. Koch, Z. Koenig, S. Kwasniewski, S. R. Laney, M. Nicolaus, A. K. Pavlov, C. M. Polashenski, C. Provost, A. Rösel, M. Sandbu, G. Spreen, L. H. Smedsrud, A. Sundfjord, T. Taskjelle, A. Tatarek, J. Wiktor, P. M. Wagner, A. Wold, H. Steen, M. A. Granskog, Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ice. Sci. Rep. 7, 40850 (2017).https://advances.sciencemag.org/content/6/39/eabc2678
Analysing the cells of the adult human heart
– Sagnik Nag, Amity University Kolkata The human heart is a complex organ of the human body comprising of 4 distinct chambers. Cardiovascular ailments are the leading cause of death around the globe. Advanced research and insights on the epidemiology, etiology and mechanism of the ailment require an in-depth understanding of the physiological functioning of […]