Glacier inputs influence organic matter composition and prokaryotic distribution in a high Arctic fjord (Kongsfjorden, Svalbard)

• Published in: Journal of Marine Systems
• Main Authors: Bourgeois, Solveig, Kerhervé, Philippe, Calleja Cortes, Maria de Lluch, Many, Gaël, Morata, Nathalie
• Other Authors: Red Sea Research Center (RSRC), Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539, CNRS-IRD-UBO-Ifremer, IUEM, Rue Dumont d'Urville, Plouzané, 29280, France, Oceanlab, School of Biological Sciences, University of Aberdeen, Newburgh, AB41 6AA, United Kingdom, CNRS, CEntre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), UMR 5110, Perpignan, F-66860, France, Univ. Perpignan Via Domitia, CEntre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), UMR 5110, Perpignan, F-66860, France, Consejo Superior de Investigaciones Científicas (CSIC), Instituto ANdaluz de Ciencias de la Tierra (IACT), Avenida de Las Palmeras 4, Granada, 18100, Spain, Akvaplan-niva, Fram Centre for Climate and the Environment, Tromsø, 9296, Norway
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier BV 2016
• Subjects: Bacteria; Biomarkers; Biopolymeric carbon; Climate change; Pigments; Polar zones; Arctic; glacier; Kongsfjord*; Kongsfjorden; Svalbard
• Online Access: http://hdl.handle.net/10754/622297; https://doi.org/10.1016/j.jmarsys.2016.08.009

With climate change, the strong seasonality and tight pelagic-benthic coupling in the Arctic is expected to change in the next few decades. It is currently unclear how the benthos will be affected by changes of environmental conditions such as supplies of organic matter (OM) from the water column. In the last decade, Kongsfjorden (79°N), a high Arctic fjord in Svalbard influenced by several glaciers and Atlantic water inflow, has been a site of great interest owing to its high sensitivity to climate change, evidenced by a reduction in ice cover and an increase in melting freshwater. To investigate how spatial and seasonal changes in vertical fluxes can impact the benthic compartment of Kongsfjorden, we studied the organic matter characteristics (in terms of quantity and quality) and prokaryotic distribution in sediments from 3 stations along a transect extending from the glacier into the outer fjord in 4 different seasons (spring, summer, autumn and winter) in 2012–2013. The biochemical parameters used to describe the sedimentary organic matter were organic carbon (OC), total nitrogen, bulk stable isotope ratios, pigments (chorophyll-a and phaeopigments) and biopolymeric carbon (BPC), which is the sum of the main macromolecules, i.e. lipids, proteins and carbohydrates. Prokaryotic abundance and distribution were estimated by 4′,6-diamidino-2-phenylindole (DAPI) staining. This study identifies a well-marked quantitative gradient of biogenic compounds throughout all seasons and also highlights a discrepancy between the quantity and quality of sedimentary organic matter within the fjord. The sediments near the glacier were organic-poor (< 0.3%OC), however the high primary productivity in the water column displayed during spring was reflected in summer sediments, and exhibited higher freshness of material at the inner station compared to the outer basin (means C-chlorophyll-a/OC ~ 5 and 1.5%, respectively). However, sediments at the glacier front were depleted in BPC (~ 0.2–0.3 mg C g DW) by 4.5 and 9 times ...