Periodic Reporting for period 2 - LeDNA (Global measure of biodiversity by understanding biogeochemical cycling of environmental DNA in lakes)
Reporting period: 2021-09-01 to 2023-02-28
The global loss and redistribution of biodiversity is a hallmark of the Anthropocene. Our challenge is to generate information about how altered biodiversity influences ecosystems and use this information to change our impact on the biosphere. To meet this challenge, we must know where species are, how their distributions change in time and why. However, current methods for determining species distributions is expensive, time intensive and hard to do for multiple species and large geographic regions- rendering global trend analysis near infeasible. We therefore need a paradigm shift. In this project we utilize the biotechnology of the fourth industrial revolution (i.e. inexpensive sequencing and computational power) to empirically change how we sample animal and plant biodiversity to solve the infeasibility problem of tracking multiple species distributions on large spatial scales. We are testing if lakes act as accumulators of eDNA in the landscape by receiving transported eDNA from rivers. We are investigating:
1. how chemical, physical, and biotic processes cause eDNA decay to understand its transport potential in the environment,
2. how much eDNA from a catchment is transported into a lake, and
3. in a global set of lakes, we will test whether eDNA measures biodiversity for large spatial scales.
If lakes accumulate eDNA from their catchments, sampling them will provide the paradigm shift needed to vastly change the cost, speed and geographic scale with which species can be surveyed through time to understand what effect their change has on the biosphere.
1. how chemical, physical, and biotic processes cause eDNA decay to understand its transport potential in the environment,
2. how much eDNA from a catchment is transported into a lake, and
3. in a global set of lakes, we will test whether eDNA measures biodiversity for large spatial scales.
If lakes accumulate eDNA from their catchments, sampling them will provide the paradigm shift needed to vastly change the cost, speed and geographic scale with which species can be surveyed through time to understand what effect their change has on the biosphere.
In the first year, cell lines were established, or partnerships made with existing research groups to source cells for conducting eDNA degradation experiments of DNA in different states. This resulted in successfully conducting a large experiment whereby four different species (two plants and two animals) were tested for degradation rates for three states (cell bound, mitochondria and dissolved DNA) under constant chemical conditions but were exposed to bacteria or no bacteria treatments. We additionally established a qPCR multiplex system that enable a high throughput analysis of the different states of eDNA in a single reaction. Additionally, laboratory methods were tested for how we could sort states of eDNA when combined in a single sample to inform planned field work. Modelling was also conducted to predict the transport time of water under different assumptions of time of concentration both in the planned field sites of the eight lake catchments in Switzerland and with a single model globally (~1.4 million lakes). In year two, a large field expedition was conducted visiting in total 237 sites were visited resulting in across eight lakes catchments in Switzerland. These are now in the process of being analyzed. Further, prioritization of global lakes was conducted to determine the best set of lakes and local partnerships are being solidified for sampling in the coming year.
The major outcome of this project will be a novel method for monitoring biodiversity on large spatial scales. In the short-term, the study of eDNA in lakes and their complete catchments, will test the limits of what can spatially be inferred from transported eDNA and determine whether lakes act as accumulators in the landscape integrating biodiversity over large areas. If they are, then the major expected outcome will be accomplished in that eDNA sampled from lakes can provide a new method for estimating regional animal and plant biodiversity that can be scaled to survey Earth’s terrestrial biosphere. The lake survey throughout the world will be a demonstration of the power of eDNA to facilitate collection of biodiversity information on large spatial scales and produce the first map with estimates of animal and plant biodiversity for terrestrial and aquatic across latitudes and ecoregions of the world based on environmental DNA surveys.