ALBERT

Description: Thousands of artificial (‘human-made’) structures are present in the marine environment, many at or approaching end-of-life and requiring urgent decisions regarding their decommissioning. No consensus has been reached on which decommissioning option(s) result in optimal environmental and societal outcomes, in part, owing to a paucity of evidence from real-world decommissioning case studies. To address this significant challenge, we asked a worldwide panel of scientists to provide their expert opinion. They were asked to identify and characterise the ecosystem effects of artificial structures in the sea, their causes and consequences, and to identify which, if any, should be retained following decommissioning. Experts considered that most of the pressures driving ecological and societal effects from marine artificial structures (MAS) were of medium severity, occur frequently, and are dependent on spatial scale with local-scale effects of greater magnitude than regional effects. The duration of many effects following decommissioning were considered to be relatively short, in the order of days. Overall, environmental effects of structures were considered marginally undesirable, while societal effects marginally desirable. Experts therefore indicated that any decision to leave MAS in place at end-of-life to be more beneficial to society than the natural environment. However, some individual environmental effects were considered desirable and worthy of retention, especially in certain geographic locations, where structures can support improved trophic linkages, increases in tourism, habitat provision, and population size, and provide stability in population dynamics. The expert analysis consensus that the effects of MAS are both negative and positive for the environment and society, gives no strong support for policy change whether removal or retention is favoured until further empirical evidence is available to justify change to the status quo. The combination of desirable and undesirable effects associated with MAS present a significant challenge for policy- and decision-makers in their justification to implement decommissioning options. Decisions may need to be decided on a case-by-case basis accounting for the trade-off in costs and benefits at a local level.

Description: Over the last 25 years, Canadian scientists have studied the permafrost environmental archives in the Klondike Goldfields south of Dawson City. In 2023, a small Canadian-German team visiting this area to sample mining exposures in the Klondike area. The goal was to conduct studies on ground ice (ice wedges and pore ice) and frozen sediments to reconstruct past landscape and climate conditions. Detailed profiles were sampled at three sites at Little Blanche Creek, Whitman Gulch and Bear Creek. Ice wedges were described in terms of their size, the color of ice, internal structure, existence and form of gas bubbles and were sampled by chain saw as blocks. The frozen sediment was cleaned, and ice, sediment and cryostructures were described, followed by sediment sampling with an axe and hammer. Separately, sediment cores were collected with a battery driven drill for biomarker studies. In our presentation, we present the first results of new field and laboratory studies. This concerns age determinations, sediment data, stable isotopes and hydrochemistry of the ground ice. We expect new knowledge regarding the reconstruction of Late Quaternary environment of Central Yukon.