Tiphane A. Figueira1, Erick Alves Pereira Lopes Filho2 , Lucas Heleno Lopes2, João P. S. Felizardo3, João P. G. Machado4, Vinícius Peruzzi de Oliveira4
1 Graduate Program in Environmental Engineering, Federal University of Rio de Janeiro, Brazil, 2 Graduate Program in Botany, National Museum, Federal University of Rio de Janeiro, Brazil, 3 Institute of Physics, Fluminense Federal University, Laboratory of Radioecology and Environmental Changes – LARA/UFF, 4 Multiuser Unit of Environmental Analysis, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
Ulva is a euryhaline seaweed that has a worldwide distribution, being known for causing most of the green tides around the world and for being cultivated especially in estuaries. It is also economically important, ranking among the most farmed seaweeds. As climate change is linked to altered salinity gradients and salinity is a major driver in seaweed distribution, we subjected Ulva sp. thalli to growth in 15, 35, and 55 psu salinity, at a 12/12h photoperiod under 100 microMol photons, for 5 days. The wet mass of the thalli was sampled on days 1, 3, and 5. Each sample weighed 4 ± 0.2 g wet mass before any treatment. Our results showed growth rates of 28 ± 1.35 (at 15 psu), 10.34 ± 4.99 (35 psu), and 27.85 ± 2.85 (55 psu) after 5 days of treatment. We found no difference between the growth rates at 15 and 55 psu (p= 0.72), whilst at 35 psu growth rates were the lowest (p<0.01). Our measurements of photosynthetic rates showed no effect by salinity. Growth in low salinity and high salinity conditions was highest, and this as well as the photosynthetic rates not changing significantly with changes in salinity were in disagreement with the literature. Increased growth in low salinity coupled with Ulva’s ability to profit from disturbed environments might indicate the increase of harmful blooms in estuarine regions as well as increased farm yields as a consequence linked to climate change.