SITES AquaNet is a standardized infrastructure for mesocosm experiments in lakes at stations Asa, Erken, Skogaryd and Svartberget. The facilities is then spread across a geographical and climatic gradient in Sweden.

SITES AquaNet infrastructure provide a broadly useable platform for experimental manipulation in lakes. This mesoscale infrastructure can be used to conduct modularized experiments across stations, allowing for general assessment of major questions in ecosystem science. Something this infrastructural facility is unique about.
In times of fast environmental change it is crucial to understand the multifaceted impacts of ecological stressors that affect ecosystems across local, regional and global scales. Assessments based on correlative research are not enough for unravelling stress-response mechanisms at broad spatial scales.

Participating field
research stations

Asa
Erken
Skogaryd
Svartberget

Measurement program
SITES AquaNet

Coordinator
Pablo Urrutia Cordero
pablo.urrutiacordero@ebc.uu.se

PI
Helmut Hillebrand

SITES AquaNet provide the following to researchers:

  • A platform for mesocosm experiments in lakes across geographical gradient. 
  • Field support for “your own” in situ experiments in both lakes and streams
  • Access to consistent time series data across a large number of stations e.g. hydrology, temperature, oxygen, pH and other chemical variables etc.
  • Connected stream-lake interaction of varying size, characteristics and climatic regions from each participating station in SITES Water, please note that there is no lake at Röbäcksdalen. 
  • Facilities/infrastructure such as physical access on rafts/floats, soil properties and lake bathymetry maps, data series from physical and chemical variables etc. that can support scientists in a wide range of different research fields.

SITES AquaNet Layers

Participating stations and their lakes

SITES AquaNet is built up at Asa, Erken, Skogaryd, Svartberget and their lakes;
Feresjön, Erken, Följesjön and Stortjärn

  • All participation research stations and their lakes are a subset of lakes within the SITES water program. The lakes vary in in character and location in relation to Sweden’s climate gradient.
  • All SITES AquaNet platforms are equipped with similar types of resources; mesocosm bags, sensors and equipment. All stations will be equipped with 16 mesocosms (each 500 liters) and associated buoyancy systems and pumps.
  • SITES Water and SITES AquaNet work together to structure and deliver data from a state-of-the-art program. 
  • As some SITES Water sites builds upon already existing stream/lake networks at some other stations more ancillary data can be obtained.

Instrumentation set up

The current set-up consists of an experimental floating platform build from modular elements that can easily be moved to different locations and re-structured to fit various experimental needs. Electricity will be available on all platforms and custom-made polyethylene bags can be employed within the floating platform as enclosures equipped with high-quality oxygen, fluorescence and temperature sensors and respective data logger systems for direct online data visualization.

All stations will be equipped with 16 mesocosms (each 500 liters) and associated buoyancy systems and pumps. Each mesocosm will be equipped with a basic set of sensors for temperature, pH, oxygen, CH4 and CO2. In addition, all stations will be equipped with similar sampling equipment. SITES AquaNet will establish protocols for time-efficient determination of the composition of bacterial plankton, phytoplankton and zooplankton.

Relevant research fields

The idea that species diversity enhances aspects of ecosystem stability has been discussed already by early ecologists (Elton 1958, Hairston et al. 1968, Paine 1969, May 1973). There has been an ongoing debate about the exact role of biodiversity for ecosystem stability and there is still no consensus view regarding the importance of biodiversity for different aspects of ecosystem stability (McCann 2000, Ives and Carpenter 2007, Sasaki and Lauenroth 2011, Cardinale et al. 2012).
 
Contradicting outcomes of experimental studies may partly be due to study-, ecosystem-, or species-specific traits that prevent researchers from finding general biodiversity-stability relationships that could be validated across a broad range of ecosystems.
 
The possibility of synchronized experiments across different locations have the potential to study stress-response patterns as a function of biogeographical, climatic and other macroecological contingencies within the fields of ecology and biodiversity-stability relationships and more.

Potential, questions that can be addressed in the SITES AquaNet platform

  • How do ecosystems react to multiple simultaneous pressures in the form of pulse and press disturbances and environmental fluctuations?
  • Which aspects of stability need to be assessed to allow the prediction of ecosystem responses?
  • How does biodiversity affect these multiple dimensions of stability and which traits are involved in these biodiversity effects?

The powerful tool of a harmonized physical infrastructure is to streamline the experimental approaches beforehand. In SITES AquaNet the same methods and treatments are applied to experiments executed synchronously in a network of experimental sites. This allows achieving general conclusions on ecological phenomena; particularly how local differences between important variables across sites (e.g. temperature, elevation, nutrients) mediate the outcomes of experimental manipulations of explanatory predictors for the phenomena.

Test experiments for training and data validation 2017

In 2017, SITES AquaNet will implement pilot experiments test, train and validate data during 2017. The tests address multiple dimension of stability (resistance, recovery, resilience, temporal stability) of compositional (biomass and composition of bacterioplankton, phytoplankton, zooplankton) and functional (respiration, primary production) response variables. Two disturbance types, one press disturbance (oligotrophication, i.e. gradual removal of nutrients from mesocosm bags) and a pulse disturbance (introduction and subsequent removal of a top predator (fish)) will be used in a full-factorial design.

The purpose of these pilot experiments during spring 2017 are two-fold:

  1. to develop standard operating procedures for experimental settings and sensor operation as well as protocols for an efficient and cost-effective analyses of plankton communities, including DNA-based sequencing methods for bacterio- and phytoplankton;
  2. to provide a test case for a larger, global endeavor similar to the Nutrient Network (http://www.nutNet.org/) in grassland ecosystems. The AquaNet infrastructure becomes particularly valuable through its links to SITES Water. Firstly, AquaNet provides an infrastructure for the implementation of experiments within the framework of a unique measurement program and secondly, develops protocols for a cheap and time-effective determination of plankton communities to be used in the long-term measurement program of the respective lakes.