Influence of salinity, temperature, dissolved inorganic carbon and nutrient concentration on the photosynthesis and growth ofFucus vesiculosusfrom the Baltic and Irish Seas

Abstract

Fucus vesiculosus from the northern Baltic Sea (5 psu) and from the Irish Sea (35 psu) were cultivated at different temperatures, salinities and dissolved inorganic carbon (DIC) concentrations with the addition of different nutrient concentrations. The influence of these abiotic factors was assessed by measuring photosynthesis as electron transport rate (ETR) and growth as relative growth rate (RGR ). When Baltic F. vesiculosus was cultivated at a DIC concentration similar to that of the Irish Sea, the ETR as well as RGR increased, but never equalled the rates of the marine F. vesiculosus from the Irish Sea. Cultivation at different salinities showed that F. vesiculosus from the Baltic has a higher ETR max and RGR at low salinities (5-10 psu) than F. vesiculosus from the Irish Sea, whose ETR and RGR decreased sharply in salinities below 20 psu. Plants from both sites grown at high nutrient concentrations, however, performed better at low salinities than those grown under low nutrient conditions. Salinity had the greatest impact on differences in ETR and RGR between the two populations, followed by differences in DIC and nutrient concentrations. There was a highly significant correlation between ETR max and RGR in plants from both sites and across the full range of culture conditions, indicating that the same amount of energy from photosynthesis is used for growth in both varieties of the species at different salinities. The photosynthesis of F. vesiculosus in the northern Baltic is close to the minimum demand for growth, which may account for their small size. The temperature optimum for F. vesiculosus from the Baltic was 4-10 C, while that for F. vesiculosus from the Irish Sea was 15-20 C. The photosynthesis of Irish Sea plants was less strongly affected by exposure to high irradiances than that of plants from the Baltic.

Temperature- and light-dependent growth and metabolism of the invasive red algaeGracilaria vermiculophylla– a comparison with two native macroalgae

“…We discovered that light and temperature have interactive effects on growth (and therefore should be quantified and reported), but Fortes & Lüning did not report light levels for their experiment; a direct comparison is therefore difficult and the reported differences could thus be due to different culture conditions. Furthermore, Nygaard & Dring (2008) reported optimum growth for F. vesiculosus comparable to this study at longterm temperatures down to 15-20°C. Overall these differences in optimum temperatures suggest the presence of regional ecotypes that are adapted to prevailing environmental conditions.…”

Seasonal photoacclimation patterns in the intertidal macroalga <em>Cystoseira tamariscifolia</em> (Ochrophyta)

“…On the other hand, C. tamariscifolia growing in RS may be subjected to different cycles of desiccation and rewetting, increasing atmospheric CO 2 uptake and nutrient incorporation; the inorganic carbon uptake in C. tamariscifolia growing in rockpools depend mainly on the amount of dissolved HCO 3 -and carbon concentration mechanisms (CCMs) through carbonic anhydrase (CA), with the consequent energy cost (Falkowski 1997). It has been reported that intertidal algae under moderate desiccation conditions have higher nitrogen and phosphate uptakes (Lobban andHarrison 1994, Nygard andDring 2008), photosynthetic rates Brown 1982, Mercado et al 1998). The carbon incorporation under emersion is higher than that under submerged conditions due to the direct uptake of CO 2 (Flores-Moya et al 1998).…”

Seasonal variations of Fucus vesiculosus fertility under ocean acidification and warming in the western Baltic Sea

“…High CO 2 and/or dissolved inorganic carbon (DIC) conditions stimulate growth and photosynthesis of different non-calcifying seaweeds (Gordillo et al 2001, Nygård and Dring 2008, Wu et al 2008, Olischläger et al 2012, Saderne 2012, Koch et al 2013). In addition to the effect of enhanced CO 2 on growth and photosynthesis of seaweeds, reproduction may be impacted by the DIC concentration in seawater.…”