Emerging Issues in Lake Superior Research

Abstract

The Aquatic Ecosystem Health and Management Society (AEHMS) sponsored the “Superior: State of the Lake” conference in Houghton, Michigan, which was hosted by the Michigan Technological University in May 2002. This was part of a continuing series of “State of the Lake” conferences organized by AEHMS following those on Lakes Huron, Erie, Ontario, Michigan, Baikal, Victoria and Winnipeg. These conferences have been designed to integrate, synthesize, and publish “state of the lake” information about various Great Lakes of the World in peer reviewed book series (Ecovision World Monograph Series) or as special issues in the journal Aquatic Ecosystem Health & Management, published by AEHMS. The Society has an excellent track record of publishing special issues on the Great lakes of the world: Large Lakes of the World: Comparative Ecology(AEHM, 2000a); Ecosystem Health of Lake Baikal, Russia(AEHM, 2000b); Great Lakes of the World: Food web, Fisheries and management (AEHM, 2002); Comparing Great Lakes of the World(AEHM, 2003). The AEHMS has also published several monographs: The Lake Huron Ecosystem: Ecology, Fisheries and Management(Munawar et al., 1995); State of Lake Erie: Past, Present and Future(Munawar et al., 1999); Phytoplankton Dynamics in the North American Great Lakes, volume 1(Munawar and Munawar, 1996); volume 2(Munawar and Munawar, 2000); Great Lakes of the World-GLOW: Food-web, Health & Integrity (Munwar and Hecky, 2001); State of Lake Ontario (SOLO): Past, Present and Future(Munawar, 2003).Very little has been published about this lake since “Limnology of Lake Superior” was published in the Journal of Great Lakes Research (Munawar, 1978). It was based on the Upper Great Lakes symposium convened at the Great Lakes Research Conference in Guelph, Ontario, 1976. The “State of the lake” conference on Lake Superior convened almost 25 years after the Guelph meeting. This conference provided an excellent opportunity for various Great Lakes researchers to present new data on diverse topics, and to interact with peers on various aspects of large lakes research. The conference was convened to provide a forum to discuss ecosystem health in scientific and management circles, increased development of eco-technologies, sensitivity of large oligotrophic ecosystems such as Lake Superior to environmental stress, and the challenging complexity of integrating topics such as ecosystem integrity, biodiversity, restoration and sustainable development. The conference's theme reflected an integration of a large range of topics and concepts to bring together a state-of-the-art status of Lake Superior, which will be published by the AEHMS in a peer reviewed Ecovision monograph currently under preparation.This special issue has been designed to focus on “Emerging issues in Lake Superior research,” one of the main topics from the conference. Lake Superior provides unique opportunities for research because of its size, ultraoligotrophic status (similar to some ultraoligotrophic oceanic regions) and its relatively low density of human population centers and industrial activities. It is the largest lake in the world by surface area and the second largest by volume. Understanding of its paleo-history depends on a detailed determination of relict shorelines; in this issue Baedke et al. present results of their current efforts to reconstruct the paleo-lake levels of the Upper Great Lakes. Investigators interested in the biogeochemistry of ultraoligotrophic freshwater ecosystems have focused their attention on this lake. In this special issue several reports identify emerging issues in contemporary limnology that are well examined in Lake Superior.Increasing interest in the role of dissolved organic matter is evident in several of the papers of this issue. Cotner et al. discuss the biogeochemistry of organic carbon, noting that the DOC pool is 10 times as large as the particulate organic carbon pool and that improved understanding of DOC origin and fate is critical for understanding C-flux in this lake. Heath and Munawar discuss the significance of phosphate uptake by bacteria and note increasing evidence that the apportionment of available P between bacterioplankton and phytoplankton appears to depend on the availability of “labile” DOC to support bacterial activities. McKay et al. present interesting thoughts regarding the possibility that Lake Superior phytoplankton may be limited by iron availability; in turn, iron availability may be mediated by DOC complexation. Perlinger et al. report emerging technologies to detect and determine the physico-chemical and biochemical properties, food web fluxes and bioaccumulation pathways of “legacy” chemicals and novel synthetic organic toxicants that are introduced to lake Superior primarily through atmospheric deposition. Edsall et al. report the use of Hexagenia burrowing mayflies in a benthic survey as a sensitive indicator of ecosystem health status in two embayments of Lake Superior. We hope that this compendium of papers will be useful in highlighting some of the research being carried out and in enhancing our current understanding of one of the largest and most pristine lakes of the world.