Sandra H. Arenas is a PhD student at Rey Juan Carlos University, Spain. She is a marine biologist with a special focus on seaweeds ecophysiology and distribution. Here, Sandra shares her recent work on adaptation of seaweeds to climate change.

The marine biologist Sandra Hernández Arenas
Personal links. ResearchGate | University Homepage
Institute. Rey Juan Carlos University, Spain.
Academic life stage. PhD student
Recent JBI paper. Hernández, S., García, A. G., Arenas, F., Escribano, M. P., Jueterbock, A., De Clerck, O., Maggs, C. A., Franco, J. N., & Martínez, B. D. C. (2023). Range-edge populations of seaweeds show niche unfilling and poor adaptation to increased temperatures. Journal of Biogeography, 50, 780-791. https://doi.org/10.1111/jbi.14572
Video abstract. Since global warming is affecting the distribution of species worldwide and the degree of adaptation to high temperatures is still unknown in most cases, this study aims to study whether the European populations of two macroalgae species differ in their thermal tolerance ranges. To do this, we selected European populations from 8 different localities of the brown alga Ascophyllum nodosum (Linnaeus) Le Jolis and 6 of the red alga Chondrus crispus Stackhouse. These populations underwent a thermal gradient experiment ranging from 12º – 30ºC to determine their upper survival temperatures (USTs). Those USTs, approximately 24°C, were used as thresholds to assess the existence of safety margins and thermal niche unfilling states by comparing then with the maximum seawater surface temperature. Both species had thermal safety margins over the last few decades. However, these safety margins are projected to disappear in the Bay of Biscay (Spain) under RCP4.5 and RCP6.0 2090–2100 IPCC scenarios for C. crispus and under RCP8.5 for both species, since those southern marginal populations are not better adapted to global warming, as revealed by the USTs.
Biography. I’m Sandra Hernández Arenas, a pre-doctoral researcher in the Biodiversity Area at Rey Juan Carlos University in Madrid, Spain. I obtained my Biology Degree from the same university in 2011-2015. Subsequently, I pursued a Marine Biology Master’s at Vigo University in Galicia, Spain from 2015-2017. Additionally, I completed an Education Master’s at Rey Juan Carlos University from 2018-2019 to become a secondary teacher.
My passion for the underwater world has led me to acquire various dive qualifications in recreational diving. I am also deeply interested in the field of education, and I fill my time by teaching laboratory classes at the university. However, I do not rule out dedicating myself fully to teaching in the future if my time through the world of research cannot continue.
My recently published paper in the Journal of Biogeography is a part of my Ph.D. thesis focused on marine macroalgae. My research primarily revolves around ecophysiology, species distribution models, niche changes, and alien species. The overarching goal of my work is conservation, specifically investigating how climate change might impact macroalgae populations along our coastlines.