Pamela A. Fernández1, Karina Villegas2, Rodrigo Torres3, Iván Pérez-Santos2,3,4, Alejandro H. Buschmann1
1Centro i~mar, CeBiB, MASH, Universidad de Los Lagos, Camino a Chinquihue km6, Puerto Montt 580000, Chile. 2Centro i~mar, Universidad de Los Lagos, Camino a Chinquihue km6, Puerto Montt 580000, Chile. 3Centro de Investigación en Ecosistemas de la Patagonia (CIEP), José de Moraleda 16, Coyhaique, Chile. 4Center for Oceanographic Research COPAS Sur-Austral and COPAS COASTAL, Universidad
Correspondence: Pamela A. Fernández pamela.fernandez@ulagos.cl
The ability of seaweeds to adapt and/or acclimate to climate change can differ between different populations, depending on their local environmental history and phenotypic plasticity. Globally, many seaweed populations have been negatively affected by multiple anthropogenic factors such as ocean warming (OW). However, local drivers such as nitrogen (N) might modulate their physiological responses to OW. In this study, we compare the physiological responses and early development of Macrocystis pyrifera to different regimes of temperature (stable–fluctuating) from populations naturally exposed to fluctuating conditions of CO2, pH, temperature, and N. Fertile sporophylls of M. pyrifera were collected from populations with high (Las Docas and Punta Lavapiés) and less exposure to upwelling events (El Tabo and Punta de Parra). Temperature, pH and nutrient concentrations were constantly monitored in each locality. At the laboratory, M. pyrifera early stages (meiospore, gametes, and juvenile sporophytes) were exposed for three months to four temperature treatments: 16°C stable, 16°C fluctuating, 19°C stable and 19°C fluctuating, simulating the average temperatures during the spring-summer months and OW scenarios. As a result, we observed great variability in the developmental (germination success, gametophytes growth, reproduction success) and physiological responses (growth and photosynthesis) among populations and temperature treatments, regardless of the upwelling effect. These differences might be given by the great variability registered in temperature and pH in each locality. However, the greatest differences among populations were found between gametophytes and juvenile sporophytes, suggesting different adaption capacities among multiple life stages of M. pyrifera.
Financial Support: FONDECYT (ANID) 11200474, 1221161, CeBiB (ANID) FB-0001, MASH (ANID) NCN2021_033.