The Species-Specific Responses of Freshwater Diatoms to Elevated Temperatures Are Affected by Interspecific Interactions

Abstract

Numerous experimental simulations with different warming scenarios have been conducted to predict how algae will respond to warming, but their conclusions are sometimes contradictory to each other. This might be due to a failure to consider interspecific interactions. In this study, the dominant diatom species in a seasonal succession were isolated and verified to adapt to different temperature ranges by constant temperature experiment. Both unialgal and mixed cultures were exposed to two fluctuant temperature treatments that simulated the temperature variations from early spring to summer, with one treatment 4 °C higher (warming scenario) than the other. We found that the specific response of diatoms to warming was affected by interspecific interactions. Spring warming had no significant effect on eurythermal species and had a positive effect on the abundance of warm-adapted diatom species, but interspecific interactions reduced this promotional effect. Cold-adapted species had a negative response to spring warming in the presence of other diatom species but had a positive response to early spring warming in the absence of interspecific interactions. In addition, warming resulted in the growth of all diatom species peaking earlier in unialgal cultures, but this effect could be weakened or amplified by interspecies interactions in mixed cultures. Our results suggest that the specific diatom species with different optimal growth temperature ranges responding to warming were expected if there were no interspecific interactions. However, in natural environments, the inevitable and complex interspecific interactions will influence the responses of diatoms to warming. This important factor should not be ignored in the prediction of organism responses to climate warming.

Trends in Diatom Research Since 1991 Based on Topic Modeling

“…First, diatoms can serve as indicators of environmental changes due to their high sensitivity and preservability. For example, diatoms respond to environmental changes (e.g., climate and salinity) by altering individual morphology/size and their assemblages [14,15,16,17,18]. Second, diatoms are a powerful surrogate for reconstructing paleoenvironmental history and even population dynamics of specific aquatic animals [19,20].…”

The Ability of Airborne Microalgae and Cyanobacteria to Survive and Transfer the Carcinogenic Benzo(a)pyrene in Coastal Regions

“…As one of the earliest organisms to populate the Earth, cyanobacteria have developed various defense mechanisms to survive in unfavorable environments. Some cyanobacteria are even capable of modulating the production of toxins in response to environmental stressors [ 51 , 52 ].…”

“…The obtained research results indicate that the addition of a small amount of benzo(a)pyrene significantly affects the change in the F v / F m parameter as well as the content of chlorophyll a in the cell, thus significantly affecting cellular stress. According to Zhang et al [ 52 ], research on M. aeruginosa revealed that this organism possesses antioxidant defense enzymes such as superoxide dismutase (SOD) and catalase (CAT). The increased activity of these enzymes can provide protection against oxidative damage caused by PAHs.…”

“…M. aeruginosa is known to produce a highly toxic compound called microcystin. However, studies have shown that this cyanobacterium can protect itself against oxidative stress caused by PAHs by stabilizing its photosynthetic apparatus and modulating protein metabolites [ 52 , 53 , 54 ]. As low values of F v / F m are often observed when photosynthetic organisms are exposed to stress, indicating photoinhibition [ 55 ], the cyanobacteria were characterized by the lowest average value of this parameter, thus representing the group most susceptible to stress.…”

Tolerance of Benthic Diatoms to Severe Environmental Stress: A Case Study in Shatt Al-Arab River, Basrah, Iraq

“…Diatoms exist and thrive across many environments ranging from cold water to hot springs (Maguire et al, 2013). Some diatoms have a rather narrow temperature range outside which cells die (Anderson, 2000;Zhang et al, 2018). On the other hand, temperature affects diatoms more than any other environmental factor and this effect can be in one of two distinct ways: directly on metabolic rates and indirectly by its impact on nutrient availability and uptake (Lewandowska et al, 2014).…”