The effects of water temperature on fatty acid content in the diatom, navicula pelliculosa

Abstract

Algae are critical to aquatic ecosystems and provide nutritious food to primary consumers due to their ability to synthesize essential fatty acids, in particular, long-chain polyunsaturated fatty acids (LC-PUFA). Aquatic ecosystems are experiencing increases in surface water temperatures as a result of anthropogenic climate change. Elevated water temperatures can potentially cause thermal stress for algae and disrupt critical physiological and biochemical mechanisms. As a response to temperature changes, fatty acid composition in membranes shifts in order to maintain membrane fluidity. To gain a better understanding of how elevated temperature influences fatty acid composition, growth experiments of a cosmopolitan freshwater diatom species, Navicula pelliculosa, were performed in a temperature-controlled laboratory environment. Diatom cultures were grown under different thermal regimes to examine the effects of temperature and time on LC-PUFA content. Temperature treatments were found to elicit an asymmetrical response in FA content, potentially resulting in reduced LC-PUFA availability.

The Implications of Parasite Roles for the Nutritional Dynamics of Food Webs

“…From the donor vessels, I aseptically inoculated the cultures into new flasks at an inoculation ratio of 1:5 and later, once established, I inoculated the cultures into new flasks at a ratio of 1:10. I inoculated the cultures on a weekly basis to ensure that they remained in the exponential phase of growth, which I verified using optical density (OD) or absorbance (A) readings from a spectrophotometer (Spectronic 20+ model) (as in Cameron 2017). I plotted the age of each culture (from the time of inoculation, in days) compared to the average OD readings at 685 nm (n = 2 flasks of algae per culture) to create a growth curve, and I measured OD across the range of 600-950 nm .…”

“…However, Cameron (2017) argued that such warming effects are dependent on the length of exposure to suboptimal temperatures. To test this, Cameron (2017) cultured the diatom Navicula pelliculosa for two weeks at 28°C (suboptimal conditions) and then at 22°C (optimal conditions) for 48 h, analyzing its FA profile at both time points; the results showed the FA contents of N.…”

“…Besides the effects of temperature on the FA composition of algae (e.g., Fuschino et al 2011;Hixson and Arts 2016;Cameron 2017), algal FA content can also be influenced by nutrient regimes (Guschina and Hardwood 2009). For example, Brett and Müller (1997) found that various green algae (e.g., Scenedesmus sp.…”