Ryan Sponseller

Big or small fish for harvesting? Effects of ontogenetic habitat shifts and bottlenecks in recruitment

Big or small fish for harvesting? Effects of ontogenetic habitat shifts and bottlenecks in recruitment

Targeting managers of trout populations, the project will provide tools to predict how different brown trout populations respond to different levels of fishing mortality and different management interventions.

The invisible carbon: an early indication of ecosystem change!

The invisible carbon: an early indication of ecosystem change!

Streams are sensitive sentinels for environmental change by their integration of processes in terrestrial and aquatic systems. Upland headwater streams in the north Swedish tundra show seasonally exceptional high concentrations of uncolored dissolved organic carbon (DOC) and high carbon dioxide concentrations.

LOREX (The Limnology and Oceanography Research Exchange)

LOREX (The Limnology and Oceanography Research Exchange)

The Limnology and Oceanography Research Exchange (LOREX) is a formal training and professional development program in international research collaboration in the aquatic sciences offered by the Association for the Sciences of Limnology and Oceanography (ASLO).

Climate change induced regime shifts in Northern lake ecosystems

This project brings together new tools and concepts in biogeochemistry and ecology, with the aims of understanding and predicting the effects of climate change on the delivery of two major ecosystem services, fish production and the net greenhouse gas balance of Northern lakes.

Taking the pulse of Swedish rivers: using metabolism to monitor ecosystem responses to environmental change

Taking the pulse of Swedish rivers: using metabolism to monitor ecosystem responses to environmental change

Project Summary

Streams and rivers carry out multiple ecosystem services that respond to and integrate natural and anthropogenic perturbations across landscapes. In northern regions, a critical aspect of this ‘integration’ involves the regulation of carbon (C) transfer from land to the atmosphere and sea. In this context, the degree to which streams and rivers transform terrestrial organic carbon (OC) and act as sources of CO2 to the atmosphere is subject to much current debate. National monitoring programs have the potential to shed light on this issue, yet these efforts rarely assess aquatic ecosystem processes. As a solution, we propose adding high frequency measurements of dissolved oxygen (DO) to current monitoring programs, which allow for the calculation of fundamental metabolic rates at daily time scales. Such measures reveal the ‘pulse’ of biological activity in running waters with the temporal resolution needed to capture changes in the degradation of terrestrial OC and CO2 production and fixation in response to diverse environmental changes. The goals of this research are to 1) determine how the rates and patterns of metabolism in Swedish rivers are shaped by regional climatic gradients and anthropogenic stressors, 2) Quantify the extent to which streams and rivers in arctic, boreal, and hemi-boreal zones degrade terrestrial OC, and contribute to CO2 evasion, and 3) Advance a simple and cost efficient method to assess metabolism that will complement current monitoring programs in Sweden by adding functional metrics

Collaborators

Jan Karlsson, Umeå University
Erin Hotchkiss, Virginia Polytechnic Institute
Hjalmar Laudon, Swedish University of Agricultural Sciences, Umeå

Funding

Formas