Spatial and temporal variation in DMSP content in the invasive seaweed Codium fragile ssp. fragile: effects of temperature, light and grazing

Abstract

The methionine-derived secondary metabolite dimethylsulfoniopropionate (DMSP) is believed to function in cryoprotection, defense against herbivory, and reduction of oxidative stress in some seaweeds. The ability to produce DMSP, and modify its concentration according to environmental conditions, may confer adaptive advantages to these algae. We studied the spatial and temporal distribution of DMSP content in Codium fragile off the Atlantic coast of Nova Scotia. Levels of DMSP in C. fragile were highest in boreal spring (~2% of total dry wt) and lowest in fall (~1%), and negatively related to seawater temperature. DMSP content differed among sites and tended to decrease or remain constant with depth. In tide pools, partially bleached algae contained less DMSP than undamaged individuals, consistent with the putative function of DMSP in response to oxidative stress. Results of field-and laboratory-based experiments, designed to examine plasticity in DMSP production by C. fragile, indicate that it increases with light intensity, exposure to sea urchin grazing, and decreasing temperature.

Detrital subsidy from subtidal kelp beds is altered by the invasive green alga Codium fragile ssp. fragile

“…However, the timing of fragmentation and attendant production of detritus by stands of C. fragile varies among regions and occurs throughout the year in some areas (Trowbridge 1996(Trowbridge , 1998. Thalli of C. fragile used for this experiment were collected during the seasonal minimum in DMSP production coincident with high water temperatures (Lyons et al 2010). In regions were fragmentation occurs during periods of low temperature in winter and spring (Fralick & Matheison 1973, Trowbridge 1993, the DMSP content of detrital fragments is likely higher, which may result in a greater deterrent effect on potential consumers and slower degradation rate than observed in our study.…”

“…We have shown that detached thalli of Saccharina latissima and Codium fragile differ significantly in their rate of degradation, and the manner in which biochemical composition and nutritional quality change during degradation, indicating that displace- Lyons et al 2010) increased slightly in C. fragile 4 wk after transplantation, when mass loss was minimal, likely in response to a decrease in water temperature with depth (Lyons et al 2010). Similarly, the concentration of DMS(P) in attached C. fragile at 5 to 7 m depth (the source of experimental thalli) increased over the course of the experiment from 2.0 to 7.0% (not shown) as temperatures decreased in the shallows from 23 to 7°C.…”

“…Transplantation stress may have caused an increase in DMSP in the first 4 wk of the experiment (Lyons et al 2010); therefore, only 4 to 16 wk were included in this analysis. The abundance of associated macrofauna, and species richness, Pielou's evenness index (J'), and Shannon's diversity index (H'), were also compared between algal species and over time (4 to 16 wk) using a 2-way ANOVA.…”

“…Dimethylsulfoniopropionate (DMSP) is another secondary metabolite found in all macroalgal phyla, with highest concentrations in green algae (Van Alstyne & Puglisi 2007). DMSP is produced, and cleaved into dimethylsulfide (DMS) and acrylic acid, as an activated defense against herbivory (Van Alstyne et al 2001, Van Alstyne & Houser 2003, Lyons et al 2010. DMSP occurs in high concentration in Codium fragile and varies seasonally in response to changing water temperature and light intensity (Lyons et al 2007(Lyons et al , 2010.…”

“…DMSP is produced, and cleaved into dimethylsulfide (DMS) and acrylic acid, as an activated defense against herbivory (Van Alstyne et al 2001, Van Alstyne & Houser 2003, Lyons et al 2010. DMSP occurs in high concentration in Codium fragile and varies seasonally in response to changing water temperature and light intensity (Lyons et al 2007(Lyons et al , 2010. Like phlorotannins in kelps, concentration of DMSP may decrease during degradation of C. fragile, but this has not been examined.…”