Desalination effects on macroalgae (part b): Transplantation experiments at brine-impacted sites with Dictyota spp. from the Pacific Ocean and Mediterranean Sea

Abstract

Desalination residual brines are mostly discharged to marine environments, which can produce osmotic stress on sensitive benthic organisms. In this investigation, we performed transplantation experiments nearby desalination plants using two brown macroalgae species from a cosmopolitan genus: Dictyota kunthii (Chile) and Dictyota dichotoma (Spain). Parameters related to photosynthetic activity and oxidative stress were evaluated at 3 and 7 days for D. kunthii, and 3 and 6 days for D. dichotoma; each at 2 different impacted sites and 1 control. We observed that brine exposition at both impacted sites in Chile generated a marked stress response on D. kunthii, reflected in a decrease of primary productivity (ETRmax), light requirement (EkETR), and an excessive thermal dissipation (NPQmax), especially at 7 days. In D. dichotoma, similar impaired photosynthetic activity was recorded but only at the highest brine influence site during day 3. Regarding oxidative stress, both species displayed high levels of H2O2 when exposed to brine-influenced sites. Although in D. kunthii H2O2 content together with lipid peroxidation was higher after 3 days, these returned to baseline values towards day 7; instead, D. dichotoma H2O2 levels increased only at day 6. This easy and practical approach has proven to provide valuable data to address potential impacts of brine discharges at global scale coastal ecosystems.

Multi-criteria analysis for sustainable and cost-effective development of desalination plants in Chile

“…Brine effluents are characterized by a salinity concentration that can double the salinity of the seawater body; this excess salinity also implies higher density (Mezher et al, 2011;Panagopoulos et al, 2019). Therefore, the discharges have been observed to mainly affect the benthic communities present in the affected area, mainly sessile communities or those with a low mobility capacity to escape from the high salinity influenced zone (Petersen et al, 2018;Sharifinia et al, 2019;Sola et al, 2020b;Muñoz et al, 2023). However, scientific experiences have demonstrated that it is possible to achieve long-term sustainable desalination when properly corrective and preventive measures are adopted (Sola et al, 2020a).…”

Desalination effects on macroalgae (part A): Laboratory-controlled experiments with Dictyota spp. from the Pacific Ocean and Mediterranean Sea

“…In spite of the latter, the potential detrimental effects of desalination have been observed to be mainly associated with the osmotic stress caused by salt excess (e.g. Del Pilar Ruso et al, 2015;De la Ossa Carretero et al, 2016;Cambridge et al, 2019Ferna ́ndez-Torquemada et al, 2019Rodrı ́guez-Rojas et al, 2020;Panagopoulos and Haralambous, 2020a;Panagopoulos and Haralambous, 2020b;Sandoval-Gil et al, 2022;Muñoz et al, 2023).…”

“…In this study, in short-term-controlled laboratory conditions, we compared photosynthetic activity and oxidative stress response in the Dictyota species under increased salinity levels similar to those found nearby brine discharges. In a complementary article (Muñoz et al, 2023), similar parameters were assessed in these species under transplantation experiments in desalination plant-impacted sites.…”