A multiple biomarker approach to tracking the fate of an ice algal bloom to the sea floor

Abstract

In ice-covered Arctic seas, the ice algal production can be the main input of organic matter to the ecosystem. Pelagic-benthic coupling is thought to be particularly tight in those areas. The increase in ice algal production in Franklin

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

“…Morata et al (2010) have demonstrated that a combination of analytical methods were necessary to verify the arrival of a food pulse that had not been detectable using fluorometric analysis of sediment pigments in the course of a spring-to-summer transition. The response of benthic communities to algal input can be rapid but of limited duration (Sun et al 2007), and we may have sampled some sites after the onset of such a rapid consumption.…”

“…In the southeastern Beaufort Sea, spring-to-summer dynamics have been studied at one time-series site in Franklin Bay (Amundsen Gulf) during the Canadian Arctic Shelf Exchange Study (CASES) in 2004. A seasonal increase in benthic carbon remineralisation was recorded (Renaud et al 2007b), whereas an increase in the availability of fresh food at the sea floor could only be confirmed after pigment analyses with a higher resolution (Morata et al 2010). A considerable increase in benthic respiration from spring-to-summer has also been reported from the North Water Polynya (NOW), where carbon remineralisation was driven by micro-and meiobenthic communities in spring and by macrobenthic communities in summer (Grant et al 2002).…”

Benthic faunal assimilation pathways and depth-related changes in food-web structure across the Canadian Arctic

“…Stable isotope values integrate the signal of the overall organic matter present in the sediment over a period of months and thus are probably not good indicators of short-term changes in the vertical flux of the organic material to the surface sediment. Assessing phytodetritus quality by means of the abundance of diatom frustules (Morata et al, 2011) or by analysing highly-branched isoprenoids derived from sea-ice algae may be more accurate to detect ice algae-derived POM in surface sediment, at least on a short temporal scale at the time of algal deposition in spring.…”

Light and nutrient effects on the settling characteristics of the sea ice diatom Nitzschia frigida

“…Although the mechanisms are not fully understood, export events often coincide with increased light, temperature, ice porosity, and ablation of the ice bottom (Apollonio ; Mundy et al ; Nishi and Tabeta ). Once released, organic material from the ice is either consumed in the water column (Tremblay et al ; Michel et al ), initiates ice‐edge algal blooms (Michel et al ; Haecky et al ; Yamamoto et al ), or settles on the benthos where it is subsequently either grazed or buried in the sediments (McMahon et al ; Renaud et al ; Morata et al ). While particulate organic matter consumed by pelagic heterotrophs may still reach the benthos as a viable food resource in the form of fecal pellets or settled molts/carcasses (Wassmann ; Goutx et al ; Elliott et al ), the amount of carbon reintroduced post ingestion can be diminished (Møller et al ).…”

“…While particulate organic matter consumed by pelagic heterotrophs may still reach the benthos as a viable food resource in the form of fecal pellets or settled molts/carcasses (Wassmann ; Goutx et al ; Elliott et al ), the amount of carbon reintroduced post ingestion can be diminished (Møller et al ). Furthermore, decomposition and digestive processes significantly impact the overall nutritional quality of material that has been ingested (Lovvorn et al ; Goutx et al ; Morata et al ), ultimately altering the relative value of material reaching the benthos directly and rapidly, vs. material settling out post ingestion and/or post decomposition that occurred during transit through the water column.…”