Magister Scientiae - MSc / The Western Cape, a province of South Africa is facing increased pressure to develop new supplies of fresh water to cater for the regions rapidly growing demand. Groundwater is being explored as a possible contributor to the freshwater supply. Development of the resource has been slow despite the existence of significant potential groundwater resources in the form of several shallow primary aquifer systems and an extensive secondary aquifer formation known as the Table Mountain Group (TMG) Aquifer. This slow development may be attributed primarily to a lack of awareness amongst key stakeholders and general ignorance in the water market with regards to the potential of this resource.

Anthropogenic stressors to freshwater environments have perpetuated water quality and quantity challenges for northern communities across Arctic Canada, making drinking water resources a primary concern for Arctic populations. To understand the ecological trajectory of freshwater supply sources, we conducted a paleolimnological assessment on two supplemental sources of freshwater in Igloolik, Nunavut, Canada. A stratigraphic examination of bioindicators (Insecta: Diptera: Chironomidae) allowed for paleotemperature reconstructions with decadal and centennial resolution over the past 2000 years. Between 200 and 1900 CE, the sub-fossil chironomid community was comprised of cold-water taxa, such as Abiskomyia, Micropsectra radialis-type, and Paracladius. Reconstructed temperatures were consistent with known climate anomalies during this period. A rapid shift in the composition of the chironomid community to warm-water adapted taxa (Chironomus anthracinus-type, Dicrotendipes, and Tanytarsus lugens-type) in the late 20th century was observed in both systems. Our results demonstrate that these lake ecosystems are undergoing marked transformations to warmer, more nutrient-rich environments, and suggest water sustainability pressures on freshwater and human systems will likely continue in tandem with ongoing climate change. To contextualize the influence of recent warming and elucidate the status of water resource vulnerability over the longer term, paleolimnological methods can be usefully applied as components of vulnerability assessments.