Assessment of the independent and combined effects of copper and polycyclic aromatic hydrocarbons on gametogenesis and sporophyte development of the kelp Lessonia spicata (Phaeophyceae, Ochrophyta)

Abstract

Coastal shores near the industrial park of Quintero Bay in central Chile exhibit increasing concentrations of copper (Cu) and polycyclic aromatic hydrocarbons (PAHs), well above international standards. This raises concern about their combined toxic effects on early development stages of kelps. Accordingly, we aimed to assess more accurately the independent and combined effects of Cu and PAHs on gametogenesis and sporophyte development in the kelp Lessonia spicata from central Chile by in vitro cultivation. Independent Cu and PAH trials were performed using increasing nominal concentrations of Cu and PAHs in the ranges 0.8–200 µg L−1 and 0.05–100 µg L−1, respectively. Cu and PAH median effective concentrations (EC50) on gametogenesis and early sporophyte formation were calculated using DRC in the R environment. Then, combined EC50 Cu + PAH trials were conducted to determine their effects on gametogenesis and sporophyte formation. Cu EC50 values on gametogenesis and sporophyte formation were up to three orders of magnitude lower than EC50 reported previously on spore germination in kelps. The gametogenesis (EC50 = 1.39 µg L−1) was more sensitive to Cu than sporophyte formation (EC50 = 11 µg L−1). Inversely, sporophyte formation (EC50 = 0.04 µg L−1) was more sensitive to PAHs (EC50 = 0.11 µg L−1). Considering the entire exposure period, the combined EC50 Cu + PAH exposure was the most harmful and rapid for L. spicata microscopic stages, especially the synergistic effect on early sporophytes. This highlights the need to acquire an integrated knowledge of the seasonal variation of pollutants and their combination on highly intervened coasts.

Transfer of Pollutants from Macrocystis pyrifera to Tetrapygus niger in a Highly Impacted Coastal Zone of Chile

“…Little information is available in the current literature on the capacity of PAHs to become bioconcentrated in this species. However, several deleterious effects in terms of sporulation, settlement, and germination were recently identified in this kelp and in Lessonia spicata exposed to Cu, Cd, and PAHs, as well as their binary and tertiary mixtures [16,17,42]. Conversely, it has been documented that individual M. pyrifera detached from the substrate can be passively dispersed over long distances, transporting both adhered animal species and algae; these detached algae are able to survive during drifting and develop reproductive structures [43,44].…”

“…These pollutants may negatively affect the organisms by decreasing successful reproduction or even causing death [14]. The bioavailability of HMs is influenced by environmental factors such as temperature, pH, salinity, solubility, and, in some cases, the presence of (and interaction with) other HMs [15][16][17]. Their toxicity is primarily related to the induction and generation of reactive oxygen species (ROS) through the Haber-Weiss reaction, which can cause damage to cellular components, such as DNA, lipids, proteins, and organelles [18][19][20][21].…”

Is Fucus a suitable biomonitoring organism for polycyclic aromatic hydrocarbon contamination? A study from the Faroe Islands

“…Interestingly, the study found a 350% increase in hydrocarbon-oxidizing bacteria on the thalli of the algae when exposed to the diesel-water mixture. Another intertidal kelp species ( Lessonia spicata ) was found to be sensitive to PAHs especially during the sporophyte formation, with the EC 50 for the inhibition of the formation of sporophytes being 0.04 µg/L PAH EPA16 though this species might be particularly susceptible to reactive oxygen species which are created in photosynthetic organisms when exposed to PAHs (Espinoza-González et al 2021 ). As a primary producer and a foundation species, Fucus is a food source and an important habitat for many invertebrate species like Idotea balthica or Tonina fluviatilis , especially in the form of shed detritus.…”