DMSP in marine macroalgae and macroinvertebrates: Distribution, function, and ecological impacts

Abstract

The production of dimethylsulfoniopropionate (DMSP) and its cleavage products are well studied in phytoplankton. However, less is known about their sources, distributions, functions, and impacts in other marine organisms. We examined the distribution of DMSP in benthic macroalgae and macroinvertebrates geographically and taxonomically. In macroalgae, concentrations significantly increased from the tropics to the poles in the northern, but not the southern, hemisphere. The increase in the northern hemisphere was due to an increase in concentrations with latitude in the Chlorophyta. This pattern was generated by a relatively high proportion of species in the order Ulvales (median [DMSP]: 145 mmol g -1 dry mass (DM)) at higher latitudes, and a high proportion of species in the orders Caulerpales and Siphonocladales (median [DMSP]: below detection level for both orders) in the tropics. Low DMSP concentrations (< 10 mmol g -1 DM) were reported from all red and brown macroalgae, except Polysiphonia and Halopytis. In macroalgae, some of the reported functions of DMSP and its cleavage products included acting as a compatible solute, an antiherbivore defense, a reactive oxygen scavenger, and a cryoprotectant. Among macroinvertebrates, DMSP occurred in higher concentrations in cnidarians than in sponges and molluscs. Concentrations in animals harboring endosymbiotic algae were 6.5 times higher than animals without symbionts. This and direct measurements of DMSP from isolated symbionts suggest that endosymbionts are a major source of DMSP for some macroinvertebrates. Diet may be a source of DMSP in animals that lack endosymbionts. The functions and impacts of DMSP in invertebrates are not well known.

Sulfur isotope variability of oceanic DMSP generation and its contributions to marine biogenic sulfur emissions

“…These differences reflect genetic and environmental factors known to influence the synthesis and degradation of DMSP, and its loss from cells (3,4). DMSP occurred in relatively high concentrations in all members of the order Ulvales [ranging from 69 ± 13-102 ± 34 μmol/g of fresh mass (FM)], and the concentrations are comparable to previous measurements from ulvoid algae in this region (26).…”

“…In the remote atmosphere, MSA, and NSS-SO 4 2− aerosols are the principal oxidation products (∼80%) of DMS (MSA/NSS-SO 4 2− is between ∼0.1 and 0.4) (30). These products are produced through reaction chains involving few branches and predominantly unidirectional radical abstraction and addition reactions (16).…”

“…We show that the sulfur isotope compositions (δ 34 S) of DMSP are depleted in 34 S relative to the source seawater sulfate by ∼1-3‰ and are correlated with the observed intracellular content of methionine, suggesting a link to metabolic pathways of methionine production. We suggest that this variability of δ 34 S is transferred to atmospheric geochemical products of DMSP degradation (DMS, MSA, and NSS-SO 4 2− ), carrying implications for the interpretation of variability in δ 34 S of MSA and NSS-SO 4 2− that links them to changes in growth conditions and populations of DMSP producers rather than to the contributions of DMS and non-DMS sources. COO − ] is a secondary metabolite that is produced and stored in large amounts by marine macroalgae (1) and microalgae (2).…”

“…Oceanic dimethylsulfoniopropionate (DMSP) is the precursor to dimethylsulfide (DMS), which plays a role in climate regulation through transformation to methanesulfonic acid (MSA) and nonseasalt sulfate (NSS-SO 4 2− ) aerosols. Here, we report measurements of the abundance and sulfur isotope compositions of DMSP from one phytoplankton species (Prorocentrum minimum) and five intertidal macroalgal species (Ulva lactuca, Ulva linza, Ulvaria obscura, Ulva prolifera, and Polysiphonia hendryi) in marine waters.…”

“…COO − ] is a secondary metabolite that is produced and stored in large amounts by marine macroalgae (1) and microalgae (2). This β-sulfonium compound is widespread among marine taxa but is particularly abundant within specific groups of phytoplankton, zooplankton, macroalgae, halophytic plants, macroinvertebrates, and fishes (3)(4)(5). DMSP plays important ecophysiological functions in marine algae by acting as an antioxidant (6), a cryoprotectant, an osmolyte, and a precursor to an activated defense system (3).…”