Spatial and temporal variability of chlorophyll and primary productivity in surface waters of southern Chile (41.5–43° S)

Diatom blooms and primary production in a channel ecosystem of central Patagonia

“…) is in good agreement with high productivity estimates reported by previous studies conducted in other regions of coastal Patagonia, such as the inner sea of Chiloé (41.5º-43ºS;Iriarte et al, 2007), the Reloncaví Fjord (41ºS; Montero et al, 2011), the Aysén region (43º-46ºS; Pizarro et al, 2005) ) and Chl-a (2 to 16 mg m -2 ) values were observed during the non-productive season (excluding August). The high variability of integrated GPP values observed during the productive season in Puyuhuapi reflects the pulsed nature and temporal heterogeneity of productivity cycles in the Patagonian fjord region generally.…”

“…In Chilean fjords ecosystems, diatoms are known to represent a significant component of the overall phytoplankton biomass (Iriarte et al, 2001;Cassis et al, 2002;Alves-de-Souza et al, 2008;Iriarte & González, 2008). In addition to efficiently transferring energy to higher trophic levels, diatoms make a significant contribution to the downward transfer of organic carbon (Iriarte et al, 2007;González et al, 2010;Montero et al, 2011;Iriarte et al 2013). Diatoms occur in highest abundance during the Patagonian fjord spring bloom, and are generally dominated by Skeletonema spp.…”

“…Diatoms occur in highest abundance during the Patagonian fjord spring bloom, and are generally dominated by Skeletonema spp. and associated with high levels of primary production (Iriarte et al, 2007;Montero et al, 2011). Despite the significant contribution that diatoms make to overall fjord productivity, important questions remain unanswered: for example, which are the main factors that trigger diatom blooms in specific fjords and channels, and which are the key species in terms of significance to annual productivity.…”

“…The productivity cycle within a number of Patagonian channels and fjords (41-51ºS) has been typically described in terms of two contrasting seasons: a productive season characterized by a marked spring diatom bloom followed by pulsed productivity events dominated by a sequence of different phytoplankton species, and then a non-productive season that predominantly features small phytoplankton cells (Iriarte et al, 2007;Iriarte & González, 2008;Czypionka et al, 2011;Montero et al, 2011;Paredes & Montecinos, 2011). Despite considerable recent research, uncertainty remains regarding the factors that modulate the seasonal phase change within Chilean fjords system, from non-productive in late autumn-winter to highly productive in late winter-autumn.…”

Patagonian Fjord Ecosystems in Southern Chile as a Highly Vulnerable Region: Problems and Needs

“…The estuarine waters are relatively poor in nutrients, with the oceanic Subantarctic Waters (SAAW) being the main source of nutrients, as documented for the southern Chile shelf margin (Silva and Neshyba 1979). In Chilean fjords, the horizontal buoyancy input resulting from freshwater runoff has an important effect on the primary production (PP) of algae that are isolated from their principal source of nutrients (i.e., the nutrients trapped below the pycnocline), thus, leading to the eventual shutdown of production after short bloom periods (Valle-Levinson et al 2007;Iriarte et al 2007). The highly seasonal variability in PP (1-3 g C m -2 day -1 ; 4) has been associated with efficient export production to the sediments (0.2-0.6 g C m -2 day -1 ; 5), suggesting that the Chilean fjord region is a major ''CO 2 sink'' during the highly productive season.…”