Weekly Reports Polarstern
The Expedition PS118 Punta Arenas - Punta Arenas
The Antarctic Peninsula is among the fastest warming regions of the world (Bentley et al., 2009; Rignot et al., 2008; Scambos et al., 2000; Vaughan et al., 2003). In 1995, the Larsen A ice shelf and in the 2002 Larsen B ice shelf disintegrated almost entirely leaving the Larsen C ice shelf as the last remaining ice shelf in the west Weddell Sea (De Angelis and Skvarca, 2003; Domack et al., 2005; Gutt et al., 2011; Pudsey et al., 2001; Rebesco et al., 2014; Rott et al., 1996; Shepherd et al., 2003; Skvarca and De Angelis, 2003; Wendel and Kumar, 2017).
In July 2017, Larsen C ice shelf calved iceberg A68. With ca. 5,800 km2, A68 is one of the largest icebergs ever recorded (Fig. 1) resulting in a significant retreat of the front of the Larsen C ice shelf. This retreat has profound influences on the environmental settings and ecosystems in the area that was previously covered by the ice shelve. Until recently, these areas were decoupled from the atmosphere and the impact of sunlight. Now they are experiencing ocean atmosphere exchange processes and primary production in the surface waters. These significant changes happen in a very short time period, forcing the ecosystems to quickly respond to the new environmental conditions. To understand the adaptation mechanisms and the resilience of ecosystems to these abrupt changes, it is necessary to collect base-line information on environmental and biological processes. Also for later repetitive studies, this baseline information is important. So far, only limited information is available from the Larsen A and B area and, due to its remoteness, hardly any information exist from the Larsen C area. Expedition PS118 with Polarstern to the Larsen shelf area is a multidisciplinary approach with the aim to collect as many data sets as possible.
One focus of PS118 is to collect information towards the understanding of the environmental and biological processes associated with ice shelf break-ups. In addition, data will be collected from the understudied Larsen shelf and slope. Data collection during PS118 is designed to answer overarching questions regarding ice sheet dynamics, ocean – cryosphere interactions, ocean circulation and a variety of biological and environmental processes including ecosystem functioning, habitat distribution and population dynamics and distributions. This diversity in disciplines is also represented from a total of 13 working groups on board. They cover the disciplines of bathymetry/hydroacoustic, biology, geology, geophysics, oceanography, and sea ice physics. Furthermore, one person will be on board for a TV documentary.
Expedition PS118 with Polarstern commences in Punta Arenas (Chile) on the 9th of February 2019 and finishes in Punta Arenas (Chile) on the 10th of April 2019. The expedition targets the Larsen C shelf. Due to the recent breakup of the giant iceberg A68 from Larsen C ice shelf, the newly exposed seabed, previously covered by A68, has become an additional target area for PS118. Further study areas are the former Larsen A and B ice shelves and an area of the Larsen continental slope that is deeply incised by canyons. The alternative working area covers the Powell and the Jane basin (Fig. 1).