Understanding the Effects of Greenland’s Melting Glaciers on Macrobenthos and Trophic Structures in Two Arctic Fjords

Student: 
Carla López Mateo

Fjords play a critical role in global and regional ecosystems as significant carbon sinks and highly productive habitats. The accelerated melting of the Greenland Ice Sheet due to climate change is affecting these fjord systems, particularly through increased freshwater discharge from both marine-terminating glaciers (MTGs) and land-terminating glaciers (LTGs). The present study investigates the differences in macrobenthic community structure in two Arctic fjords, Igaliku (influenced by LTG) and Tunulliarfik (influenced by both MTG and LTG), sampled at the mouth and head of each fjord. Stable isotopes of δ13C and δ15N were used to assess differences in trophic niches of macrobenthos and demersal fish assemblages. Differences in macrobenthic community composition across stations were observed. However, macrofauna richness, density and trophic diversity was similar in both fjords, although this may be underestimated due to sample size. Higher richness was observed at the mouth of the fjords. This difference was reflected in the isotopic niches, especially within Igaliku, where subglacial melt had an important effect. This study highlights the importance of glacier type on fjord ecosystems and the need of understanding these dynamics to assess future climate change effects on Arctic marine environments.