Ocean acidification influences plant-animal interactions: The effect of Cocconeis scutellum parva on the sex reversal of Hippolyte inermis

Abstract

Ocean acidification (O.A.) influences the ecology of oceans and it may impact plant-animal interactions at various levels. Seagrass meadows located at acidified vents in the Bay of Naples (Italy) are considered an open window to forecast the effects of global-changes on aquatic communities. Epiphytic diatoms of the genus Cocconeis are abundant in seagrass meadows, including acidified environments, where they play key ecological roles. A still-unknown apoptogenic compound produced by Cocconeis triggers the suicide of the androgenic gland of Hippolyte inermis Leach 1816, a protandric hermaphroditic shrimp distributed in P . oceanica meadows located both at normal pH and in acidified vents. Feeding on Cocconeis sp . was proven important for the stability of the shrimp’s natural populations. Since O.A. affects the physiology of diatoms, we investigated if, in future scenarios of O.A., Cocconeis scutellum parva will still produce an effect on shrimp’s physiology. Cell densities of Cocconeis scutellum parva cultivated in custom-designed photobioreactors at two pH conditions (pH 7.7 and 8.2) were compared. In addition, we determined the effects of the ingestion of diatoms on the process of sex reversal of H . inermis and we calculated the % female on the total of mature individuals -1 (F/mat). We observed significant differences in cell densities of C . scutellum parva at the two pH conditions . In fact, the highest cell densities (148,808 ±13,935 cells. mm -2 ) was obtained at day 13 (pH 7.7) and it is higher than the highest cell densities (38,066 (±4,166) cells. mm -2 , day 13) produced at pH 8.2. Diatoms cultured at acidified conditions changed their metabolism. In fact, diatoms grown in acidified conditions produced in H . inermis a proportion of females (F/mat 36.3 ±5.9%) significantly lower than diatoms produced at normal pH (68.5 ±2.8), and it was not significantly different from that elicited by negative controls (31.7 ±5.6%).

Ocean Acidification Affects Volatile Infochemicals Production and Perception in Fauna and Flora Associated With Posidonia oceanica (L.) Delile

“…As regards the observed differences in the behavioral responses to various concentrations of infochemicals, they are quite common in this kind of study. A bouquet of volatile compounds may trigger contrasting and sometimes opposite responses, according to doses (Mutalipassi et al, 2019(Mutalipassi et al, , 2020.…”

“…Ad hoc designed photo-bioreactors were used to culture C. scutellum var. parva, Diploneis sp., and U. prolifera at pH 7.7 and 8.2, in three replicates for each species and each pH, as described by Mutalipassi et al (2019). About 35,000 cells.…”

“…Marine organisms use chemical cues to interact and communicate within environments suffused with information produced by prey, predators, competitors, and conspecifics (Brönmark and Hansson, 2000;Pohnert et al, 2007;Zupo and Maibam, 2011;Mutalipassi et al, 2019Mutalipassi et al, , 2021Zupo et al, 2019). This communication has evolved from bacteria to plants and animal to be considered a biological machineries able to sense and process key information (Vos et al, 2006).…”

“…Metabolic changes due to high concentrations of CO 2 influence plant-animal communications and may cause a misunderstanding in the interpretation of the information, as it was previously demonstrated both in benthic (Zupo et al, 2015(Zupo et al, , 2016Mutalipassi et al, 2019) and in planktonic organisms (Havas and Rosseland, 1995;Maibam et al, 2015). In parallel, algae living in an acidified environment may modify the patterns of production of secondary metabolites (eventually playing the role of infochemicals), and this additional factor should be taken into consideration to understand "wrong" responses of target organisms (Poore et al, 2013;Jin et al, 2020).…”

Editorial: Cyanobacterial and microalgal compounds: Chemical ecology and biotechnological potentials

“…In addition, several infochemicals are produced by seagrass-associated organisms with a role in the regulation of macroalgal-associated microbial communities within benthic marine environments (Saha and Weinberger, 2019;Mutalipassi et al, 2021). Thus, the molecules produced by seagrasses and their associated organisms play important roles in mediating ecological interactions among the organisms inhabiting these highly productive communities (Mutalipassi et al, 2019;Mutalipassi et al, 2020). In the complex array of interactions triggered by chemical cues, antagonistic interactions promote diversified adverse cascading effects on both benthic and planktonic species (Ribeiro et al).…”