Uptake kinetics and storage capacity of dissolved inorganic phosphorus and corresponding dissolved inorganic nitrate uptake in Saccharina latissima and Laminaria digitata (Phaeophyceae)

Abstract

Uptake rates of dissolved inorganic phosphorus and dissolved inorganic nitrogen under unsaturated and saturated conditions were studied in young sporophytes of the seaweeds Saccharina latissima and Laminaria digitata (Phaeophyceae) using a “pulse‐and‐chase” assay under fully controlled laboratory conditions. In a subsequent second “pulse‐and‐chase” assay, internal storage capacity (ISC) was calculated based on VM and the parameter for photosynthetic efficiency Fv/Fm. Sporophytes of S. latissima showed a VS of 0.80 ± 0.03 μmol · cm−2 · d−1 and a VM of 0.30 ± 0.09 μmol · cm−2 · d−1 for dissolved inorganic phosphate (DIP), whereas VS for DIN was 11.26 ± 0.56 μmol · cm−2 · d−1 and VM was 3.94 ± 0.67 μmol · cm−2 · d−1. In L. digitata, uptake kinetics for DIP and DIN were substantially lower: VS for DIP did not exceed 0.38 ± 0.03 μmol · cm−2 · d−1 while VM for DIP was 0.22 ± 0.01 μmol · cm−2 · d−1. VS for DIN was 3.92 ± 0.08 μmol · cm−2 · d−1 and the VM for DIN was 1.81 ± 0.38 μmol · cm−2 · d−1. Accordingly, S. latissima exhibited a larger ISC for DIP (27 μmol · cm−2) than L. digitata (10 μmol · cm−2), and was able to maintain high growth rates for a longer period under limiting DIP conditions. Our standardized data add to the physiological understanding of S. latissima and L. digitata, thus helping to identify potential locations for their cultivation. This could further contribute to the development and modification of applications in a bio‐based economy, for example, in evaluating the potential for bioremediation in integrated multitrophic aquacultures that produce biomass simultaneously for use in the food, feed, and energy industries.

Phosphate and Nitrate Uptake Dynamics in Palmaria palmata (Rhodophyceae): Ecological and Physiological Aspects of Nutrient Availability

“…This is comparable to the ISC in the perennial seaweeds Saccharina latissima and Laminaria digitata with an ~45 d capacity to storage of DIN. With completely filled internal pools for DIP, it can be estimated that S. latissima can maintain its assimilation rate under DIP‐depleted conditions for ~90 d (Lubsch and Timmermans 2019). In contrast, the opportunistic seaweed U. lactuca exhibited an ISC that would last 10 d for DIP and DIN (Fujita 1985, Lubsch and Timmermans 2018).…”

“…For example, our data on uptake dynamics and growth rates support P. palmata to be a potent species for bioremediation purposes in layered multispecies cultures, especially regarding the N:P stoichiometry, while a considerable amount of valuable proteins and carbohydrates is produced at the same time. For example, to improve efficiency in bioremediation and enhance yield, the slow growth rates and oscillating uptake strategy by P. palmata can be complemented by S. latissima , which showed a mean growth of 4% · d −1 and similarly high, but uncorrelated and linear uptake rates of DIP and DIN in a ratio of 1:13 under V M in comparable conditions (Table 1; Lubsch and Timmermans 2019). Such a multispecies culture can be useful, especially in close proximity to fish farms, which commonly generate large amounts of effluents in fluctuating quantities, including nitrogenous compounds and phosphates.…”

Temperature mediates the outcome of species interactions in early life-history stages of two sympatric kelp species

“…Lamouroux are sympatric throughout most of their distribution area (Lüning 1990). In the North-East Atlantic, records of both species range from Arctic Svalbard (Fredriksen and Kile 2012) to southern range-edge populations in Brittany, France (Loiseaux-de Goër and Noailles 2008). Laminaria digitata has a wider temperature tolerance range than A. esculenta and the latter is considered to be the more northern species as it does not occur in the North Sea or English Channel (Munda and Lüning 1977).…”

Kelp in IMTAs: small variations in inorganic nitrogen concentrations drive different physiological responses of Saccharina latissima

“…However, phosphorus addition had no effects on photosynthesis and pigments of Chondrus crispus, while nitrogen addition did, indicating on one hand that phosphorus limitations are rare, and on the other that nitrogen plays a bigger role in pigment production (Chopin et al 1995). Accordingly, S. latissima has been observed to grow in phosphorus-depleted water for at least 2 weeks due to an internal phosphate storage in cell vacuoles (Lubsch and Timmermans 2019). In our study, we found that a small difference in ammonium and phosphorus enrichment between IMTA1 and IMTA2 resulted in a higher pigment content.…”