Prelle Lara R, Albrecht Martin, Karsten Ulf, Damer Pauline, Giese Tabea, Jähns Jessica, Müller Simon, Schulz Louisa, Viertel Lennard, Glaser Karin
Applied Ecology and Phycology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.
Front Microbiol. 2021 Apr 12;12:642811. doi: 10.3389/fmicb.2021.642811. eCollection 2021.
The German Baltic Sea coastline is characterized by sea-land transitions zones, specifically coastal peatlands. Such transition zones exhibit highly fluctuating environmental parameters and dynamic gradients that affect physiological processes of inhabiting organisms such as microphytobenthic communities. In the present study four representative and abundant benthic diatom strains [s, , sp. (st. 1) and sp. (st.2)] were isolated from a Baltic Sea beach and three peatlands that are irregularly affected by Baltic Sea water intrusion. Ecophysiological and cell biological traits of the strains were investigated for the first time as function of light, temperature and salinity. The four strains exhibited euryhaline growth over a range of 1-39 S, surpassing salinity of the respective brackish habitats. Furthermore, they showed eurythermal growth over a temperature range from 5 to 30°C with an optimum temperature between 15 and 20°C. Growth rates did not exhibit any differences between the peatland and Baltic Sea strains. The photosynthetic temperature optimum of the peatland diatom isolates, however, was much higher (20-35°C) compared to the Baltic Sea one (10°C). All strains exhibited light saturation points ranging between 29.8 and 72.6 μmol photons m s. The lipid content did not change in response to the tested abiotic factors. All data point to wide physiological tolerances in these benthic diatoms along the respective sea-land transitions zones. This study could serve as a baseline for future studies on microphytobenthic communities and their key functions, like primary production, under fluctuating environmental stressors along terrestrial-marine gradients.
德国波罗的海海岸线以海陆过渡带为特征，特别是沿海泥炭地。这些过渡带呈现出高度波动的环境参数和动态梯度，影响着诸如微型底栖植物群落等栖息生物的生理过程。在本研究中，从波罗的海海滩和三个受波罗的海海水入侵影响的泥炭地中分离出四种具有代表性且数量丰富的底栖硅藻菌株[ 种（菌株1）和 种（菌株2）]。首次研究了这些菌株的生态生理和细胞生物学特性与光照、温度和盐度的关系。这四种菌株在1 - 39‰的盐度范围内表现出广盐性生长，超过了各自咸淡水栖息地的盐度。此外，它们在5至30°C的温度范围内表现出广温性生长，最适温度在15至20°C之间。泥炭地菌株和波罗的海菌株之间的生长速率没有差异。然而，与波罗的海硅藻（最适温度为10°C）相比，泥炭地硅藻分离株的光合最适温度要高得多（20 - 35°C）。所有菌株的光饱和点在29.8至72.6 μmol光子·m⁻²·s⁻¹之间。脂质含量并未因测试的非生物因素而发生变化。所有数据表明，这些底栖硅藻在各自的海陆过渡带具有广泛的生理耐受性。本研究可为未来关于微型底栖植物群落及其关键功能（如初级生产）在陆地 - 海洋梯度波动环境压力下的研究提供基线。
