A salinity gradient study at contrasting nutrient loadings in lake mesocosm: the gradient experiment includes 8 different salinities at two nutrient levels in lake meosocms.
Project lead: Meryem Beklioğlu, Erik Jeppesen, Juan Pablo Pacheco
Timing: The experiment is planned for 12 weeks between 1 Sep and 1 Dec 2021. The preparation for the experiment will take place August.
We encourage a range of Transnational Access (TA) applicants to apply: Including technological partners, and research institutions. As we plan to observe whole-ecosystem responses, expertise with interest in microbial (including bacteria, hetetrophic flagellates and ciliates) and larger communities (including phytoplankton, zooplankton, benthos) and their interactions or processes (e.g. metabolism) are welcome to apply. A total of ca. 250 person days will be allocated to external users through Transnational Access provided by AQUACOSM-plus for 2021.
Deadline for TA application at METU-Mesocosm System is 30 April 2021, 13:00 CET.
Introduction to the project:
Global temperature and precipitation patterns have already been changing as a result of climate change, and the change in the semi-arid and Mediterranean climate zones are predicted to be particularly dramatic. A 25-30% decrease in precipitation and a parallel increase in evaporation in the Mediterranean region are expected by the end of the 21st century. Moreover, the land in drought is expected to double from 2000 to 2100. The magnitude of these changes and a consequent increase in salinity poses a major threat to the functioning and biodiversity of lakes. Novel studies that we have performed in North West China have shown drastic reductions in biodiversity (taxon richness), food chain length and average trophic position in the pelagial of the lakes with increased salinity. This indicates a loss of lake ecosystem functioning, and some studies suggest marked regime shifts when specific salinity thresholds are reached. However, the knowledge on the effect of warming on saline lakes is fragmented and far from at the level achieved for freshwater lakes. This is unfortunate as the proportion of lakes that are saline is expected to increase substantially in the near future. In the CLIM-SALTLAKES project (http://salinelakes.ims.metu.edu.tr), we aim at providing novel understanding of the structure and functioning of saline lake ecosystems and their response to key stressors (warming, abstraction and external nutrient loading).
METU Mesocosms II: Experimental facilities and plan
In the project CLIM-SALTLAKES we are currently established two sets of high-tech mesocosm facilities with a flow-through design will be constructed and equipped adequately to assess climate-change effects on lakes under varying salinity and nutrient levels- one at METU Ankara and one at METU Mersin. Each of the experimental facilities will comprise (1) 16 mesocosm tanks, each containing approximately 3 m3 water with adjustable salinity levels enabling 2×2 factorial experiments, (2) a central flow system that will supply water from main tank or groundwater source to the tanks, equipped with a volume-adjustable pump to be able to simulate different residence time scenarios (detailed in the following sections), (3) electrical heating systems which will be installed at least 8 – optimally 12 of the tanks and able to operate at different temperatures independently, (4) a paddle system that will mix the tanks to avoid thermal stratification of the water without causing the disturbance of the sediment at the tank bottom, (5) a set of sensors that will optimally consist of conductivity, temperature, oxygen and chlorophyll-a sensors (probably excluded due to budget constraints) and a web-based monitoring and control system for data-logging and the remote control of heating, mixing and flow systems.
In this autumn we will run a gradient experiment with 8 different salinities at two nutrient levels simultaneously at both facilities (with a natural difference in temperatures). The experiment will include both a pelagic and a benthic (sediment added) component
TA days (and flight tickets coverage) can only be used at (to) the Ankara facilities, but specific samplings in the other facility may be conducted by the team in Mersin (headed by Korhan Özkan), if not too demanding and provided successful negotiations!- or you can go yourself paid by your own funding including cost of stay, travel and transport.
AQUACOSM (call is closed)
There will be no opening for new TA applicants in 2021 in the frame of AQUACOSM. The project planned in 2020 (see Opening for Transnational Access in 2020) was postponed to 2021 with already approved TA applicants who will be offered TA.
Determining the effects of high DOC and warming on the microbial and planktonic food web structure and efficiency.
Project lead: Meryem Beklioğlu, Gülce Saydam and Dilvin Yıldız.
Timing: The experiment is planned for eight weeks between 1 May- 31- July. The preparation for the experiment will take place May 2020. The experiment will be conducted during the following 8 weeks.
We encourage range of Transnational Access (TA) users to apply: Including technological partners, and research or teaching institutions. As we plan to observe whole-ecosystem responses, everyone with expertise or interest in microbial (including bacteria, hetetrophic flagellates and ciliates) and plankton communities (including both phytoplankton and zooplankton) or pelagic processes (e.g. metabolism) is welcome to apply. We specifically invite researchers and trainees to work with in general microbial loop, phytoplankton, and zooplankton community as well as especially worked with bacterial and phytoplankton community structures (16SrRNA), zooplankton and different food sources assays etc. A total of at ca. 120 person days will be allocated to external users through Transnational Access provided under AQUACOSM for 2020.
Introduction to the project: Globally, freshwater ecosystems are warming at unprecedented rates and are simultaneously experiencing increased runoff of DOC (brownification) through flash floods, with little known consequences for future conservation of biodiversity and ecosystem functioning of freshwater lakes. In aquatic systems, phytoplankton (autotrophs) and bacteria (heterotrophs) are basal producers, acting as energy source for higher trophic levels, and thus shape the food webs depending on their production and composition. The increased input of dissolved organic carbon with brownification can further support mixotrophic algae which are at a competitive advantage over obligate phototrophs, as they can utilise bacterial prey as a source of carbon and energy and overcome growth limitations imposed by low-light conditions from the brownification.
The balance between autotrophs and heterotrophic bacteria is governed by both bottom–up factors such as light, temperature, nutrients (C, N, P) availability, and top–down effects, e.g., grazers. Changes in the relative importance of autotrophic and heterotrophic basal production, induced either by top–down or bottom–up drivers, will affect the food web efficiency (FWE) through energy transfer to higher trophic levels since bacteria are thought to be of poor nutritional quality.
We hypothesised high temperature and DOC levels;
- give advantages heterotrophic, as compared to photoautotrophic processes, that mixotrophs can be favoured.
- competitive interactions among different phytoplankton taxa and thereby to reduce overall phytoplankton species as well as their trait richness. Loss of traits related to resource use and growth, which can have a serious outcome for ecosystem functioning, food web dynamics and trophic transfer efficiencies.
- Impact of grazing pressure of large zooplankton grazers may also change the outcome of competitive interactions among different phytoplankton taxa (this will be tested through mini experiment within mesocosms with/out meso-zooplankter)
- heterotrophic basal production will enhanced and this will affect the food web efficiency (FWE) through energy transfer to higher trophic level (zooplankton) since bacteria are thought to be of poor nutritional quality.
We will perform a mesocosms experiment in a full factorial design with 2 treatments (DOC and Temperature) and controls each replicated 4 times for two months from June and July 2020. DOC will be obtained from local sources and concentration around 8 mg/L, which occurs during flash flood events, will be used. Half of the mesocosms will be heated up to a 6oC which is anticipated to occur as among the highest temperature through global warming.
We will quantify changes bacterial, phytoplankton and zooplankton in terms of community function and community composition. We will characterize the resistance of the different communities to the DOC pulse and warming. Measurements include several abiotic variables including physico-chemical, bacterial and phytoplankton abundance and community composition, trait diversity (microscopically as well as 16 &18SrRNA). Both micro- & mesozooplankton community structure, and biomass will be determined. Metabolism as a pelagic process will also be planned to be measured.
METU Mesocosm System participate in the Joint Mesocosm Experiments – JOMEX: Systems responses to recurrent pulses of dissolved organic carbon (DOC). Project lead: Meryem Beklioğlu, Gülce Saydam and Dilvin Yıldız. 01 May-31 July 2019.
Timing of the METU Mesocosm System experiment: The large-scale mesocosm experiment is planned for eight weeks between 1 May- 31- July. In month May preparation for experiment will be carried out. The experiment will be conducted during following 8 weeks and after-work, where all participants are expected to participate as an integral part of the application period.
We encourage a wide range of Transnational Access (TA) users to apply: Including public authorities, technological partners, and research or teaching institutions. As we plan to observe whole-ecosystem responses, everyone with expertise or interest in microbial (including bacteria, hetetrophic flagellates and ciliates) and plankton communities (including both phytoplankton and zooplankton) or pelagic processes is welcome to apply. We specifically invite researchers and trainees to work with in general microbial loop, phytoplankton, and zooplankton community as well as especially worked with bacterial and phytoplankton community structures (16SrRNA), pigment composition of phytoplankton (HPLC), phytoplankton nutrient limitation assays etc. A total of at ca. 220 person days will be allocated to external users through Transnational Access provided under AQUACOSM for 2019. It is anticipated that AQUACOSM will support stays of at least 8 to 10 persons.
Introduction to the project: The study aims at investigating the systems responses to dissolved organic carbon (DOC) pulses from terrestrial sources as a part of Joint mesocosm experiments of Aquacosm (- JOMEX), which will demonstrate the ability of the Aquacosm consortium to perform joint directed experiments along gradients from the Arctic to the Mediterranean and from freshwater to full marine systems. Such joint experiments will allow disentangling site-specific effects from general effects of experimental manipulations and thereby increase its predictive power. Through the changes in precipitation pattern in the eastern Mediterranean lately, winter snow packs have been largely replaced with early and late spring heavy rains and consequent of intensive flush floods. Such conditions increase transport of matter from terrestrial environments into aquatic systems is a highly relevant aspect of global change even in Eastern Mediterranean in Turkey;
Consequences DOC pulses for ecosystem dynamics are still poorly understood. The response to the disturbance with a pulse nature should depend on the composition of plankton communities and their history to the exposure to terrestrial DOC pulses in terms of frequency and strength. It is therefore expected to have strong site-specific differences in the response to a defined DOC pulse especially in lakes where DOC pulse is not a regular type of disturbance. To investigate the effect sizes of site-specific and general responses we will have 12 mesocosms, 4 controls, 4 replicates including a highly standardized DOC source and 4 replicates including a local, more site-specific DOC source. We will follow the responses of bacteria, phytoplankton and zooplankton to the DOC pulses twice. Once in the beginning of the experiment and then 3 weeks after second pulse of DOC will be given to analyse the resistance, resilience and recovery of the communities. The same mesocosm experiments will be carried out with only single pulse of DOC in European waters, from freshwater to marine systems and from Arctic to Mediterranean environments to evaluate general responses along the latitudinal gradient across the different aquatic domains.
We will investigate the response of different plankton communities to a two DOC pulses and will follow the reaction of the system after this strong disturbance in terms of resistance, resilience and recovery. We hypothesize that 1) systems, which experience regular disturbances by DOC pulses are more resistant to such a pulse and 2) second pulse may create a certain level of resistance capacity; 3) systems with high initial functional diversity will have a faster recovery towards initial conditions
Twelfe mesocosms with (2 meters height and 1.2 m diameter) will be filed by pumping water in an oligo-mesotrophic lake. Great care will be taken to fill control and treatment mesocosms with exactly the same method and at the same time to ensure a maximum initial community similarity between all mesocosm. We will perform the experiment with twice pulses of DOC, the concentration will be 2 mg/L with a highly standardized DOC form (HuminFeed; HUMINTECH, Grevenbroich, Germany) and with a local DOC source. The first pulse of DOC will be followed for 3 weeks and then the second pulse will be added and followed again.
Measurements: We will follow the transient dynamics of a plankton community after a DOC pulse. Bacterial, phytoplankton and zooplankton parameters in terms of community function and community composition will be measured. We will characterize the resistance of the different communities to the DOC pulses and hypothesize systematic differences. Measurements that are central to test the hypotheses will be performed at all sites in comparable ways; additional measurements (extended parameter list) will be performed (supported by other funds and cooperation between partners) and will allow site-specific further insights into experimental dynamics. All measurements will follow described SOP procedures assembled within AQUACOSM
Abiotic environment measurements
- Temperature: daily
- pH: daily
- Oxygen: daily
- Conductivity: daily
- Light (µmol PAR): daily
Nutrients, total & particular organic carbon (TOC, POC), particular organic nitrogen (PON) measurements
- Total phosphorus & dissolved inorganic phosphorus (TP, DIP): twice a week
- Nitrate (NO3), nitrite (NO2), ammonium (NH4): twice a week
- Particulate organic nitrogen (PON): twice a week
- Silicate (Si): twice a week
- Particulate organic carbon and total organic carbon (POC, TOC): twice a week
Bacterial parameter measurements
- Bacterial abundance (fluorescence based methods: FlowCytometer/ fluorescence microscope): twice a week
Extended parameter list:
- Bacterial community structure (16SrRNA)
- Bacterial production
Phytoplankton parameter measurements
- Phytoplankton chlorophyll a (extracted): daily
- Phytoplankton community structure (Lugol fixed samples for microscopy): at start, middle and end day.
Extended parameter list:
- FlowCytometry counts
- Chlorophyll a fractionated (0.2, 2, 10 µm filter size)
- Phytoplankton community structure (16SrRNA)
- Pigment composition of phytoplankton (HPLC, Wright et al. 1991)
- Size distribution (Cell counter)
- Microscopic analyses of microzooplankton (Lugol samples):
- Mesozooplankton samples (> 250µm), microscopic analyses of abundance and community composition:
- (https://www.aquacosm.eu/download/deliverables), for measurements were SOPs not necessarily exist relevant references are given.
Microplastics – Evaluate negative effects of microplastics in shallow freshwater lakes. Project lead: Meryem Beklioglu. 01/06-30/09
The planned mesocosm experiment at METU will start in June 2018 and run until September. We will start preparing the sediment acclimation to low P level in January with more intense preparatory work in April and May 2018. Users approved for AQUACOSM TA are welcome to participate in the proposed experiment as well as in the preparation phase. We offer at least 210 person-days to external users during year 2018 of the AQUACOSM Transnational Access provision. We aim for 6 persons staying for 35-40 days in 2018.
Introduction: Approximately 311 million metric tons (MT) of plastic were produced in 2014 alone, and production is steadily increasing each year. Up to 10 % of the plastic produced each year worldwide ends up in the aquatic environment, where it persists and accumulates. Plastic does not last forever, and the aquatic environment is suitable for plastic degradation. Physical, chemical, and biological processes are fragmenting the original plastic pieces of litter, turning the aquatic environment into a soup of microplastics. The mass of plastic in certain parts of the ocean is already surpassing the mass of plankton, and in the relatively near future, when the process of plastic degradation reaches its peak, the abundance of plastic micro and nanoparticles will be considerably greater than the count of plankton.
Current scientific research on microplastics is predominantly focused on marine environment and on individual species, while freshwater studies, including mesocosm studies, are lacking significantly. To the best of our knowledge, only 2 mesocosm studies were performed in the past in which aquatic organisms were exposed to microplastics. However, both of the studies were performed in the marine environment, and in fact can be characterized as an outdoor microcosm studies (10 L containers) rather than real mesocosm studies. Since freshwater systems also contain copious amount of microplastics which can interact with virtually all freshwater organisms that have shown in some of the laboratory experiments. There is an urgent need to perform world first freshwater, environmentally realistic, outdoor mesocosm microplastics study to understand the fate of microplastics.
Our underlying hypothesis is that the exposure to environmentally relevant concentration of microplastics in water and sediment will cause; decline in the biomass of organisms in the food chain (e.g. phytoplankton, zooplankton, invertebrates andfish); reduce the predatory evasion capabilities of zooplankton from fish; cause changes in the community structure of both the zooplankton and phytoplankton; and induce pathomorphological changes in the mentum apparatus of Chironomus spp. – a sentinel benthic macroinvertebrate.
The main objective of this study is to evaluate negative effects of microplastics in shallow freshwater lakes by exposing water and sediment of mesocosms simultaneously to the environmentally relevant mixture of various microplastic polymers (cocktail of microplastics) and not to individual microplastic types (current trend in the single species laboratory experiments). Performing a mesocosm study with a mixture of microplastic is very important as in the nature we do not have freshwater systems that are contaminated only with a single plastic polymer. Different types of microplastic have different densities resulting in a different distribution patterns in the aquatic ecosystem while many aquatic organisms move/migrate throughout the day and may interact with different microplastic polymers from different compartments of the ecosystem. On the other hand, benthic burrowing organisms are able to interact only with the high-density microplastic polymers. Furthermore, different types of microplastic polymers may induce different toxicity. Thus, in order to truly understand the negative effects of plastic littering on freshwater ecosystem we have to test for those effects using the relevant littering mixture of plastic polymers.
Therefore, we propose a mesocosm experiment with an environmentally relevant concentration of microplastic in all of its compartments (surface, water column, and sediment) of 0.007 g microplastic per m2 of surface water; 2 g microplastic per m3 for water column; and 8 microplastic g per m2 of sediment all mixed in a single mesocosm container (in 4 replicates). An additional 10 X concentration exposure and 0 X (control) group will be setup as well. For this purpose, we will use a different buoyancy microplastics of 0.95; 1-1.01; and > 1.05 (pre-mixed with sediment) gcm-3 plastic polymers for surface, water column, and sediment, respectively. Based on the available freshwater literature on the composition of microplastics in various compartments we propose that the sediment layer of microplastics in the mesocosm exposure consist of: 45% polyethylene; 20 % polystyrene; 15% poplypropylene; 10% polyamide; and 10 % polyvinylchloride. On the other hand surface layer will be exposed to 50% polyethylene; 40% poplypropylene; and 10% polystyrene. For the water column there are really no reliable data for freshwater, however based on the required density of the plastic to maintain buoyancy in freshwater this should predominantly be polyethylene with 1-1.01 gcm-3 density, which we will use in the experiment for the water column.
Proposed methodology: We propose to use 12 cylindrical-shaped mesocosms (8 experimental + 4 control), maximum volume 1360 L each, on a floating platform in the middle of a lake. Microplastics will had to be added immediately to the sediment during the mesocosms setup, while the water surface and water column microplastics will have to be added later when turbidity levels return to normal and after the acclimation period of zooplankton. All measurements will be performed weekly for 4 weeks. The first measurement will be performed on day 0 of the experiment immediately after the addition of water column/ water surface microplastics. At each sampling event, turbidity, dissolved oxygen, water temperature, pH, total nitrogen, nitrite, nitrate, un-ionized ammonia, soluble reactive phosphorous, particulated reactive phosphorous, total phosphorus, photosynthetically active radiation (PAR light penetration), Chl-a, zooplankton biomass, phytoplankton biovolume and community structure, zooplankton: phytoplankton ratio, chironomids biomass and mentum deformations will be measured. After 4 weeks, fish will be added in order to determine the difference in predatory pressure of fish on zooplankton in microplastic contaminated mesocosms vs controls. After the addition of fish measurements will be taken again weekly for the next 4 weeks. At the end of experiments all fish will be collected alive from the mesocosms and transferred to the lab where they will be kept for an additional 24 hours allowing them to defecate any microplastic which they ate immediately before the collection. After 24 hours fish will be euthanized, organs dissected and checked for microplastics accumulation. Plastic accumulation will be routinely checked in zooplankton as well during each sampling. Furthermore, there will be serious of additional laboratory experiments have been planned to test predator evasion capacity of zooplankton and changes in the mentum apparatus of Chironomus spp at different concentrations of microplastic types.
Orta Doğu Teknik Üniversitesi (ODTÜ), Middle East Technical University (METU), Üniversiteler Mahallesi, Dumlupınar Bulvarı No:1 06800 Çankaya Ankara/TURKEY, 06800
METU Campus in Ankara, Turkey
39°53’17.39″ N 32°47’2.99″ E (DMS)
Description of the infrastructure: The METU Mesocosm System is based at the METU campus in close proximity to the Limnology Laboratory (<1 km) and is a semi-mobile system that can be transferred to other locations by dismantling and mantling again. It consists of 16 cylindrical (1.2 m diameter) robust fibreglass tanks either 1.2 m or 2.2 m tall. In situ, the upper edges of all mesocosms are attached to pontoon bridges 20 cm above the water surface to avoid incursion of water during windy periods. Eight mesocosm tanks are arranged in two rows for ease of access. The pontoon bridges are wood constructions and the floating devices consist of 32 plastic barrels, each 120 L. The METU Mesocosm System is free floating and anchored only at the platform end, which, irrespective of wind direction, serves as a wave breaker and landing point for boats.
The METU Mesocosm System offers set-ups of low and high-water levels and the connection to sediment layers. Water levels differ between 1 and 2 m in the 1.2 and 2.2 m deep mesocosms, respectively. A 10 cm deep sediment layer can be added to each mesocosm, containing 90% (by volume) washed sand (grain size <1 mm) and 10% sediment from a lake for assembling the sediment mixture for the mesocosms. To simulate shallow, fully mixed lakes, the water in the mesocosms is continuously circulated during experiments using electrically powered pumps. To standardise initial conditions and enable the potential for developing a diverse flora and fauna, the mesocosms can be inoculated with a mixed sample of sediment, plankton, aquatic plants and fish.
The Limnology Laboratory operating the METU Mesocosm System is equipped with sampling gear, analytical instruments (e.g. auto-analyser for N, and other nutrient analyses, microscopes, HPLC, flow-cytometer, sampling gear for water, fish and macrophyte sampling) and a walk-in climate room., METU has a central laboratory facility equipped with elemental analyser (particulate C and N analyses), ICP-MS (trace elements analyses), Fourier transform infrared spectrometer (FTIR), as well as modern molecular-biology laboratories.
Prof. Meryem Beklioğlu
water depth and nutrients (both TP and TN)
Role of water level on ecosystem processes (e.g. C and N) as well as impact of food additives (TiO2) on food web structure and ecosystem processes
Role of hydrological alteration on ecosystem structure and function of shallow lakes
Modality of access under AQUACOSM: A total of at least 630 person-days will be allocated to external users during years 2-4 of the AQUACOSM Transnational Access provision. A minimum access for 9 persons is envisaged for 20 days each year. External users will be prioritised for using the mesocosms throughout the AQUACOSM TA activities. To maximise scientific output, efforts will be made to integrate the AQUACOSM TA activities into other projects at the facility. Access to the facility by international scientists has already been rewarded by a publication in a leading ecotoxicological journal.
Modality of access under AQUACOSM-plus: A minimum of 500 person-days will be allocated to external users through TA provided under AQUACOSM-plus. It is anticipated that AQUACOSM-plus will support stays of at least 4-5 persons for 65 days per year in M10-21 and M34-45. To maximise the scientific outcome, efforts will be made to integrate the TA activity with other on-going and planned projects at the facility. International collaboration at METU has already produced a high impact factor publication in addition to publication of the REFRESH project. In 2018, an in- situ mesocosm experiment investigating the impact of microplastics on the littoral food web was carried out with 10 students and scientists supported through TA during AQUACOSM. For summer 2019, METU Mesosystem System are participating in the AQUACOSM-JOMEX experiment with 13 TA participants from Europe and Brazil.
Services currently offered by the infrastructure: The METU Limnology Laboratory offers scientific experience and instruments needed for analyses of nutrients, identification of phytoplankton, zooplankton, macrophytes (see above). Users also get access to METU’s fully equipped central laboratory facility. METU Mesocosm System set-up provide natural opportunities to work on lake water level changes, and consequently water volume changes and salinisation induced through evaporative water loss in two different water depths, for a better understanding of climate change. Each set of low and water level mesocosms (12 each set) can be used separately for different purposes. The set-up allows investigating the effects of drought in relation with eutrophication or toxic chemicals on salinisation, water level change, trophic structure, dynamics, nutrient/toxic chemical balances, organisms from bacteria to fish, metabolism, adaptation and microevolution.
Support offered under AQUACOSM: Users will be given access to the mesocosm facility as well as the full range of laboratories and instrumentation available at the METU Mesocosm System and METU Limnology Lab. This includes physical, logistic, technical and scientific support. AQUACOSM scientific staff and the task leader will further assist users with supervising and training as well as providing assistance throughout the stay.
Support offered under AQUACOSM-plus: All visitors will have access to the full range of laboratories and instrumentation available at the METU Mesocosm System and METU Limnology Lab, physical, logistic, technical and scientific support will be provided. The AQUACOSM-plus Post-Docs and PhDs, and the project leader will further assist the users with running scientific supervision, training and technical assistance throughout the stay.