To tip or not to tip: The Window of Tipping Point Analysis for social‐ecological systems

We introduce six steps to define a “Window of Tipping Point Analysis” which serves as a framework to increase the understanding of processes and tipping points in social-ecological systems. We apply the Window of Tipping Point Analysis to a mathematical model and two case studies (i.e., Baltic Sea and the Humboldt Current Upwelling system), focusing on three aspects. In “to tip or be tipped” we look at agency in preventing (or driving) tipping. In “to be tipped or not to be tipped” we discuss intertemporal developments and chosen time periods for delineating regime shifts. In “to tip or not to tip” we discuss the desirability of states and their relation to the elements included. We argue that agency in tipping-point management, the occurrence of tipping points, and desirable states depend on the window chosen for the analysis

Oxygen in the Tropical Pacific POSTRE II First Tracer Survey, Cruise No. M135, March 01 - April 08, 2017, Valparaiso (Chile) - Callao (Peru) POSTRE-III

Cruise M135 was a contribution to the DFG Collaborative Research Project (SFB) 754: “Climate-Biogeochemistry Interactions in the Tropical Ocean” with the main goal to better understand the the role of diffusive and advective pathways connecting water within the bottom boundary layer (i.e. the water directly affected by sediment processes) to the pelagic and surface ocean. To achieve this, we have injected a conservative tracer (CF3SF5) within the bottom boundary layer at three different sites along the Peruvian coast at a depth of about 300 m in October 2015 that was mapped during M135. Tracer sampling was carried out by measuring water samples from the CTD-rosette water bottles. In total 144 CTD casts were carried out. From 132 CTD profiles 2828 samples for CF3CF5 investigations were gained and on most stations the tracer could be found. In addition 48 trace metal CTD’s were recorded and trace metal and chemical samples taken from the rosette bottles. On 166 of the CTD profiles oxygen samples were taken and on 94 CTD profiles nutrient samples were collected. Microstructure measurements were made on 24 stations and 2 gliders were deployed. For geological investigations at 5 locations multicorer and long gravity cores were taken. Continuous underway measurements of CO2,N2O and CO as well as continuous ADCP and thermosalinograph recording was made on 37 days. The cruise M135 was very successful; most systems on METEOR worked well and all planned objectives were reached