Minimising losses to predation during microalgae cultivation

Abstract

We explore approaches to minimise impacts of zooplanktonic pests upon commercial microalgal crops using system dynamics models to describe algal growth controlled by light and nutrient availability and zooplankton growth controlled by crop abundance and nutritional quality. Losses of microalgal crops are minimised when their growth is fastest and, in contrast, also when growing slowly under conditions of nutrient exhaustion. In many culture systems, however, dwindling light availability due to self-shading in dense suspensions favours slow growth under nutrient sufficiency. Such a situation improves microalgal quality as prey, enhancing zooplankton growth, and leads to rapid crop collapse. Timing of pest entry is important; crop losses are least likely in established, nutrient-exhausted microalgal communities grown for high C-content (e.g. for biofuels). A potentially useful approach is to promote a low level of P-stress that does not adversely affect microalgal growth but which produces a crop that is suboptimal for zooplankton growth.Electronic supplementary materialThe online version of this article (doi:10.1007/s10811-017-1112-8) contains supplementary material, which is available to authorized users.

Occurrence, fates and potential treatment approaches for removal of viruses from wastewater: A review with emphasis on SARS-CoV-2

“…It may lead to virus reduction in wastewater or could help protect the viruses from various inactivation processes, thereby further contributing to the waterborne transmission of the pathogenic viral particles [ 128 ]. Further, microalgae also serve as the base of aquatic food webs and fed upon by various predators like zooplanktons and protozoa; particularly the rotifers, copepods, and ciliates [ 129 ]. The predation of microalgae may aid in the removal of viruses which are trapped onto the microalgal EPS or adhered by the electrostatic interactions.…”

Recent Advances in Algal Biomass Production

“…Slowest zooplankton growth was observed under high light/P ratio [117]. Flynn et al (2017) also reported through predictive modeling that low level of P stress can be strategically applied to create suboptimal conditions to zooplankton growth without causing detrimental conditions for algal growth [118]. Another potential strategy to control certain type of predators is use of high level of CO 2 in the culture medium.…”

Modeling the impact of rotifer contamination on microalgal production in open pond, photobioreactor and thin layer cultivation systems

“…Also, changes in food quality resulting from alterations in the quantity or ratio of nutrients in the culture medium may influence rotifer population dynamics [12]. For instance, Flynn et al [69] modeled the influence of varying microalgal C/N/P ratios on the invasion success of predators and the resulting predator-prey dynamics in intensive microalgae production cultures [69]. Cultures with microalgae having low N/C and/or P/C ratios reduced predator growth and experienced less biomass losses.…”