Colloquium

THE 46th INTERNATIONAL LIEGE COLLOQUIUM ON OCEAN DYNAMICS

Low oxygen environments in marine, estuarine and fresh waters

University of Liège - Place du 20-Août, 7 - 4000 Liège - BELGIQUE


Terms of reference

Low oxygen conditions have already been reported for various aquatic systems, from lakes, estuaries and coastal areas to off-shore regions of the World Ocean, where water ventilation is not able to renew the oxygen consumed by degradation of organic matter.

In the coastal ocean, dead zones have spread exponentially since the 1960s and have been reported for more than 400 systems (e.g. Baltic, Black, Kattegat Sea, Gulf of Mexico, East China Sea) with 39 % of them along the coast of Europe. In shallow areas, where the bottom is occupied by ecologically and economically valuable benthic communities, hypoxic/anoxic conditions may lead to and have already resulted in catastrophic losses.

Eastern boundary upwelling systems (EBUSs) are characterized by high biological activity and heterotrophy that, in combination with weak ventilation, results in oxygen minimum zones (OMZs) in sub-surface waters. Suboxic waters extend from shallow depths over several hundred meters of the water column and support major perturbation of marine biogeochemical cycles. Furthermore the OMZs play a critical role on atmospheric chemistry through emission of climate reactive trace gases. These regions are also the siege of complex air-sea-land interactions that the current generation global models cannot properly resolve, which has put a stringent limitation on our predictive capabilities at a wide range of timescales.

Inland waters are hotspots of biogeochemical cycling in the terrestrial biosphere. Holomictic lakes usually present seasonally bottom anoxic waters while meromictic lakes are among the systems having a permanently anoxic deep waters, in which anaerobic processes generate reduced compounds (CH4, H2S, NH4+...). The seasonal or permanent oxic-anoxic interface presents a redox gradient, in which various biogeochemical processes take place (some unique), mediated by a diverse community of microorganisms.

In the coming decades and centuries, it is foreseen that deoxygenation will increasingly stress aquatic ecosystems in a way that is currently ignored on the global scale, but admitted as only local problems. The expansion of O2 minimum zones and resulting biogeochemical and ecological changes will make impossible the Good Environmental Status of marine and freshwater ecosystems, as well as their functioning and ability to underpin the delivery of services. These themes are in the focus of several international initiatives (SOLAS, IMBER, GEOTRACES, CLIVAR, etc.) and projects (PERSEUS, HYPOX, EMODNET, etc.).

The 46th Liege colloquium will investigate new developments and insights related to the critical problem of ocean deoxygenation, low oxygen zones in marine and freshwater systems. More specifically, the following topics will be considered:

  • Oxygen time series and instrumental developments: How to optimize the spatial and temporal coverage of oxygen survey, through which autonomous in situ sensors and platforms? How to refine our estimations of the different terms in the oxygen budget: benthic oxygen demand, surface fluxes, photosynthesis/respiration balance? Which sensors for detecting nanomolar levels of oxygen? Could an early monitoring allow reacting and adapting management strategies when a year of strong hypoxia is foreseen?
  • Deoxygenation in various systems: Inland aquatic systems (lakes and ponds, fjords and bays, rivers and estuaries, inland seas, etc.), coastal and off-shore marine systems (OMZs in EBUSs, marine shelves, open marine systems and oceans). What are the differences and similarities between these systems, which drivers are important and what consequences are observed/expected on different spatio-temporal scales?
  • Deoxygenation, marine resources and structure of the foodweb: sensitivity, resistance, resilience and recovery of marine resources (e.g. benthic organisms, fishes), what are the important factors (e.g. duration and frequency of the hypoxic event, stage of development of the organism)? Adaptation of biocenoeses to low oxygen levels (difference between communities exposed to permanent hypoxic areas over many millennia with those recently exposed), modification of the traits of the community in regions recently affected by hypoxia, how to define an index of hypoxia severity that quantifies its impacts on the living organisms and ecosystem services? By removing some components of the trophic web and modifying the cycling of essential elements oxygen deficiency may change the structure of the foodweb.
  • Deoxygenation and biogeochemical cycles. Oxygen availability impacts on biogeochemical cycles both directly and indirectly. In oxygen deficient waters, the degradation of organic matter requires the use of alternate final electron acceptors (e.g. NO3, MnO2, Fe(OH)3, SO4, CO2) changing the balance of chemical elements (e.g. N, C, P). Microbial communities can form consortia that lead to the coupling of several processes and elements such as anaerobic CH4 oxidation that can be coupled to sulfate-reduction, iron-reduction, denitrification. Also oxygen deficiency alters the cycling of major chemical elements by, for instance, controlling the loss of fixed N via denitrification and anammox in the water column and the sediments, and causing the remobilization of P bound to iron oxides in the sediments. In addition, as it affects the living communities in general deoxygenation may change the ability of the system to sequestrate carbon dioxide with eventual links to the acidification dynamics. Finally, Oxygen Minimum zones are key regions in the climatic gas budgets such as CO2, N2O, CH4, DMS, halogenated compounds impacting on climate variability.
  • Meromictic systems, oxic-anoxic interfaces, and microorganisms: In meromictic environments, C, N and S cycles may be strongly coupled, due to different microbial activities, involving archaea and bacteria. The varying nature of the processes taking place raises many questions, such as which denitrification process prevail and why, which is the contribution of autotrophic microorganisms such as methanotrophs and nitrifiers to organic carbon production and ecosystem productivity, etc. The Baltic and Black Seas, and deep tropical lakes (L. Tanganyika, L. Kivu), and reservoirs are water bodies in which these microbial processes driving biogeochemical cycles are being studied.
  • The development of models able to identify and disentangle the mechanisms (physical versus biogeochemical), drivers (climate versus land use impact), spatial and temporal variability (from the coastal to the deep ocean) of ocean deoxygenation. Which tools can be used to provide recommendations to local environmental authorities in relation to management strategies of river discharges for controlling the level of bottom hypoxia? Which strategies can be developed to value information provided by the large scale models (IPCC class)?
  • Paleoproxies of hypoxia (e.g. foraminifera, ostracods, sediment texture, chemical and mineral composition): Which (paleo)-proxies (biological, mineralogical, chemical) can be used to reconstruct the long term history of hypoxia and to establish pre-impacted baselines? The evolution of hypoxia in the coastal ocean can be inferred from microfossils, biomarkers and the chemical and mineralogical composition of bottom sediments. However, accurate quantitative proxies for palaeo-oxygenation remain elusive and distinguishing the effects of hypoxia from those of eutrophication without DO-depletion poses a considerable challenge. Among the biomarkers; pigments from anoxygenic photosynthetic bacteria, preserved in sediments, are excellent indicators of anoxic conditions in the past.
  • Deoxygenation in a global change context: impacts of natural variation, global change and land use on oxygen depletion. In the future, the temperature rise will tend to increase hypoxia by enhancing the metabolism of organisms, reducing the oxygen solubility in the water column and reducing the ventilation by increasing the stratification. As most of the effects of climate change on the local scales are as most of the effects of climate change on the local scales are not well understood, strongly adaptive management strategies of the river discharges are required to restrain the damages of hypoxia on the ecosystems.

Keynotes (already accepted):

  • Nancy Rabalais (accepted)
  • Lothar Stramma (accepted)
  • Karen Wishner
  • Silke Severmann (accepted)
  • Eugene Turner (accepted)
  • Dubravko Justic (accepted)
  • Klaus Jurgens (accepted)
  • Zouhair Lachkar (accepted)
  • Niels-Peter Revsbech (accepted)
  • James Murray (accepted)

Thematic Sessions & Keynote speakers (to be updated)

  • 1. Deoxygenation, marine resources, ecosystem functioning and structure of the foodweb. Conveners: Lisa Levin & Carol Robinson - Keynotes: Karen Wishner
  • 2. Deoxygenation and biogeochemical cycles. Conveners: Jack Middelburg & Wajih Naqvi - Keynote: James Murray
  • 3. Life and processes in redox gradients. Conveners: Sean Crowe & Steven Hallam - Keynote: Klaus Jurgens
  • 4. Paleoproxies of hypoxia. Conveners: Caroline Slomp & Daniel Conley - Keynote: Silke Severmann
  • 5. Modelling hypoxia. Conveners: Temel Oguz & Marilaure Grégoire - Keynotes: Eugene Turner & Dubravko Justic & Nancy Rabalais
  • 6. Oxygen time series and instrumental developments. Conveners Allan Devol & Alberto Borges - Keynote: Niels-Peter Revsbech
  • 7. Eastern Boundary upwelling systems (EBUS) as natural SOLAS laboratories. Conveners: Véronique Garçon & Francisco Chavez - Keynote: Zouhair Lachkar
  • 8. Deoxygenation in a global change context. Conveners: Jing Zhang & Andreas Oschlies - Keynote: Nancy Rabalais and Lothar Stramma

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Special Issue In "Biogeosciences"

A special issue will be published in "Biogeosciences" with contributions from the authors of the colloquium.

Contributions from first author of an oral or poster presentation during the colloquium are welcome.

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Scientific Organizing Committee

  • Steve Ashby (US)
  • Hermann Bange (Germany)
  • Alberto Borges (Belgium)
  • Carles Borrego (Spain)
  • Steven Bouillon (Belgium)
  • Arthur Capet (Belgium)
  • Francisco Chavez (US)
  • Daniel Conley (Sweden)
  • Sean Crowe (Canada)
  • Bronwen Currie (Namibia)
  • Jean-Pierre Descy (Belgium)
  • Allan Devol (US)
  • Boris Dewitte (France)
  • Véronique Garçon (France)
  • Dimitri Gutierrez Aguilar (Peru)
  • Marilaure Grégoire (Belgium)
  • Steven Hallam (Canada)
  • Jose Martin Hernandez-Ayon (Mexico)
  • Klaus Jurgens (Germany)
  • Sergey Konovalov(Ukraine)
  • Andrey Kostianoy (Russia)
  • Louis Legendre (France)
  • Lisa Levin (US)
  • Filip Meysman (NE)
  • Jack J. Middelburg (NE)
  • Wajih Naqvi (India)
  • Temel Oguz (Turkey)
  • Andreas Oschlies (Germany)
  • Aurélien Paulmier (France)
  • Carol Robinson (UK)
  • Caroline P. Slomp (NE)
  • Bo Thamdrup (Denmark)
  • Jing Zhang (China)

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Registration

You can register to the 46th Liege Colloquium by filling the form below.

Registration form









If you have difficulties with the registration form, please e-mail this information to oceanphys@ulg.ac.be.

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Abstract submission

The submission of abstracts is still possible but as poster

If you have some questions, please contact oceanphys@ulg.ac.be

To submit an abstract, please use our online submission system.

If you want your abstract to be considered in one of the thematic sessions, please specify the name of the session during the submission.

If you have problems with the online submission system, you can send your abstract by e-mail to oceanphys@ulg.ac.be, using one of the templates below to format it.

The abstract must fit on a page.

Deadlines

  • 24th January 2014: submission of abstracts  (Late Contributions may still be considered as a poster)
  • 21th February 2014: decision of the Scientific organizing committee of accepted abstracts
  • 7th March 2014: preliminary program will be sent to registered participants

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Program

Program 2014

Abstracts

  • For poster presentation: Poster should fit within a vertical frame with 125 cm height and 92 cm width
  • For oral presentation: You will have 15 minutes of presentation and 5 minutes for questions

Registration fee

Registration fee for the 46th International Liège Colloquium on Ocean Dynamics is 275 € if payment is received before March 30th, 2014.

After March 30th, 2014 the registration fee will be 330 €

Payements can be made by:

  1. BANK Transfer  (see details below)
  2. Cheques, Eurocheques or Cheques on an American Bank in US Dollars. (Add 10% if you pay by cheque!) (See details below)
  3. Visa/Mastercard/American Express/Paypal  (Paypal account is not necessary in some countries to go through paypal paiement, see options)
  4. Optional message to organizers
  5. Cash money.

The registration fee includes :

  • all the documents
  • coffee breaks
  • participation to the Colloquium dinner held at the "Crowne Plaza Hotel" (Wednesday evening)
  • the ice breaker party (Monday evening)
  • one copy of the proceedings

Once paid, the registration fee can not be reimbursed

Bank transfer

Modelenvironment account: 001-4193631-09

IBAN: BE52 001419363109
BIC: GEBABEBB

BNP Paribas - FORTIS BANQUE:
rue du Sart Tilman, 373
4031 Angleur
Belgium

Do not forget to:

  • mention the name of the participant in the bank transfer communication ("firstname & lastname of the participant / Colloquium 2014").
  • pay extra costs (bank charges)

Cheque

Cheques must be made out to:

Dr Salim Djenidi
Modelenvironment
University of Liège
Sart Tilman B5a
4000, Liège
Belgium

Do not forget to:

  • Add 10% if you pay by cheque for bank charges.
  • mention the name of the participant in the bank transfer communication ("firstname & lastname of the participant / Colloquium 2014").

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Announcement

Colloquium announcement 2014