Effects of salinity on the physiology of the red macroalga, Acanthophora spicifera (Rhodophyta, Ceramiales)

Abstract

Salinity is an important abiotic factor since it is responsible for the local and/or regional distribution of algae. In coastal regions, salinity changes with prevailing winds, precipitation and tide, and particularly in extreme intertidal conditions. Acanthophora spicifera is a red seaweed that occurs in the supratidal region in which changes in abiotic conditions occur frequently. Th is study evaluated the eff ects of salinity on the metabolism and morphology of A. spicifera. Algae were acclimatized under culture conditions with sterilized seawater for seven days. Experiments used diff erent salinities (15 to 50 psu) for seven days, followed by metabolic analyses. Th is study demonstrates that extreme salinities aff ect physiological parameters of A. spicifera, such as decrease in growth rate, as well as morphological parameters and concentrations of secondary metabolites. Acanthophora spicifera exhibited high tolerance to 25 to 40 psu, with little change in physiology, which favors the occurrence of this species in diverse environments. However, 15, 20, 45 and 50 psu were the most damaging and led to loss of biomass, depigmentation of apices, and the highest concentrations of antioxidant metabolites. Th e 50 psu treatment caused the greatest changes in general, greatly reducing a biomass and chlorophyll content, and facilitating the presence of endophytes.

Effects of Ultraviolet Radiation (UV‐A+UV‐B) on the Antioxidant Metabolism of the Red Macroalga Species Acanthophora spicifera (Rhodophyta, Ceramiales) From Different Salinity and Nutrient Conditions

“…Nitrate or ammonium can increase photoprotection capacity in red macroalgae by stimulating the accumulation of N compound UV photoprotectors, that is, MAAs . The depletion of photosynthetic activity by high salinities and UVR is avoided, or diminished, by the accumulation of MAAs in N‐enriched thallus . In addition to providing a UV‐screen, MAAs also present high antioxidant capacity .…”

“…An abiotic factor that can cause harmful responses and physiological effects on cells in aquatic organisms is change in salinity . Extreme salinity can reduce the growth rate of thallus, as seen in Pterocladiella capillacea (S. G. Gmelin) Santelices & Hommersand , Gracilaria crassa Harvey ex J. Agardh and Acanthophora spicifera . Most studies reporting on the effects of salinity on macroalgae involve growth and morphology and photosynthetic performance , while ignoring the effects on antioxidant metabolism.…”

Macroalgae Aquaculture in Southwestern Florida as a Potential Tool for Nutrient Sequestration

“…The species G. tikvahiae is a euryhaline species that can withstand a wide salinity range (Hill, 2001) and surprisingly the lower salinity levels within Tarpon Bay did not appear to give this species a competitive advantage. Conversely, whereas A. spicifera has been shown to exhibit an increased tolerance of salinities, ranging from 25 to 40 psu, the higher the salinity, the greater the loss to the algae's overall biomass (Pereira et al, 2017) effectively making waters with higher salinity unsuitable for long-term growth of this species. The relatively low-salinity of the water in Tarpon Bay may therefore be primarily responsible for the generally strong growth of A. spicifera overall during this experiment.…”

“…The relatively low-salinity of the water in Tarpon Bay may therefore be primarily responsible for the generally strong growth of A. spicifera overall during this experiment. While there are many abiotic factors that are influential to algal growth, salinity is an environmental parameter that strongly influences the distribution, locally or regionally, of algae (Pereira et al, 2017).…”

Composición y fluctuación estacional de especies formadoras de florecimientos macroalgales en la laguna costera El Carmen, Cárdenas, Tabasco, golfo de México

“…Aun cuando las concentraciones de nutrientes parecieran no ser limitantes, otros factores pueden serlo, ya que los cambios en la salinidad podrían limitar a las especies que no se ven favorecidas por salinidades bajas. Por ejemplo, para A. spicifera se llevó a cabo un estudio que demostró que esta se puede desarrollar adecuadamente en salinidades desde 25 hasta 40UPS, pero debajo de ellas o por arriba sufre afectaciones en su biomasa y en su coloración (Pereira et al 2017). Esto pudiera explicar la presencia/ausencia de estas especies importantes en los otros sitios visitados, además del tipo de sustrato que se encuentra en ellos, ya que 2, 3 y 4 no presentan un sustrato en el cual las macroalgas se puedan adherir, mientras que en 1 y 5 las macroalgas se hallaron adheridas a los restos de conchas y estructuras que sobresalían sobre el Composición y fluctuación estacional de especies formadoras de florecimientos macroalgales en la laguna costera El Carmen, Cárdenas, Tabasco, golfo de México…”