Different responses of two common Arctic macrobenthic species (Macoma balthica and Monoporeia affinis) to phytoplankton and ice algae: Will climate change impacts be species specific?

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

“…The southeastern Beaufort Sea is one of the most diverse Arctic shelf regions (Piepenburg et al 2010). Local community composition can be quite variable (Cusson et al 2007), which involves changes in trophic positions and, therefore, in carbon cycling efficiency (Tamelander et al 2006;Sun et al 2009). A better proxy than mere biomass would be achieved if functional Polar Biol (2011) 34:2025-20382033 123 composition of benthic communities were considered in the analysis (Bolam et al 2002;Michaud et al 2005), and hence, we coarsely separated biomass into infauna and foraminifera for analysis of driving factors.…”

“…After the ice melt, sufficient fresh detritus is reaching even greater depths and the level of benthic activity generally rises . The metabolic rate is still primarily determined by the actual availability of high-quality food rather than by total sediment pigment concentration (Sun et al 2009). The significance of infaunal biomass in summer only could be explained by a dormant stage of organisms during starvation periods.…”

“…The findingselevated chlorophyll a (Chl a) concentrations under ice ), more than twice as high absolute export rates but only slightly higher benthic respirationsuggest that there was a distinct spring bloom but lateral advection of organic matter into the central Arctic Ocean, which resulted in a lack of a seasonal benthic activity boost (Lepore et al 2007). Enhanced benthic respiration has been related to higher nutritive quality of the phytodetritus reaching the seabed Sun et al 2009). In the Barents Sea, a sharp increase in benthic activity was related to the supply of fresh food, as indicated by high Chl a export and high sediment pigment concentrations ).…”

“…There is still controversy about the actual scope and direction of future changes in primary production and vertical flux patterns (Wassmann et al 2008). Regardless, shifts in benthic community metabolism and composition are expected (ACIA 2004;Grebmeier et al 2006b;Carroll et al 2008;Sun et al 2009;Archambault et al 2010) and are likely to influence the ecosystem at higher trophic levels (Bluhm and Gradinger 2008). Our incomplete knowledge about spring-to-summer dynamics of benthic processes makes it difficult to reliably predict their response to climate-induced changes in the abiotic environment and to concurrent changes in the timing and magnitude of primary production, the quality of organic material deposited on the seafloor, and the composition of benthic communities.…”

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

“…Enhanced benthic activity (SOD) in April/ May may have contributed to higher bioturbation as many benthic organisms increase burrowing activities. Previous studies have shown that the benthos can use rapidly ice algae as food source (McMahon et al 2006;Sun et al 2009). The lack of an increase in sedimentary chl a concentration in the present study may, then, be a result of the rapid use of phytodetrital inputs due to a higher benthic activity, as suggested in Renaud et al (2007), combined with a reworking and burial of the sedimented organic material.…”