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Workshop 1

Biogeochemistry-ecosystem interactions on changing continental margins

Shelf sea and continental margin ecosystems, including estuaries, exhibit natural fluctuations in material cycles due to climate variability, but also suffer from anthropogenic stressors of global (such as CO2-induced warming, ocean acidification and enhanced nutrient element transport via the atmosphere), and regional/local impacts (eutrophication/pollution from agriculture and industry in individual watersheds, altered nutrient ratios, coastal hypoxia, intensification of sea floor use, and overexploitation of fish stocks). We need to understand the linear and non-linear responses of biogeochemical and ecological processes to such drivers, which are diverse in the level of disturbance, temporal and spatial scales. This is because they strongly affect the resource value of shelf seas and continental margin systems. Therefore, there is a great deal of societal interest to recognise and possibly manage ecosystem services in a changing world. Our session asks the following overarching questions:

  • Can we better understand the dynamics of biogeochemical cycles in continental margin ecosystems by segregating effects of natural forcing variability from long-term trends driven by human actions? (The former are supposedly forced by interannual and decadal variability in the regional climate system, while the latter include effects from the ever-increasing anthropogenic CO2 emission, rising SST, shifting hydrological patterns, atmospheric and riverine delivery of anthropogenic nutrients, and direct impacts from pollution, fisheries, energy extraction, invasion, coastal development, etc.)
  • Which combinations of natural variability of the external forcing, human-induced environmental changes (e.g. rising sea levels, stratification, and increased storminess), compound effects (e.g. eutrophication enhanced acidification and hypoxia), synergistic interactions, compensating or ameliorating interactions, additive effects, thresholds and tipping points and additional stresses by direct human foodweb manipulation and habitat destruction induce or promote non-linear responses (“regime shifts”) in marine and coastal ecosystems?

Answering these questions entails the clarification of several poorly understood processes, by which modified continental margin ecosystems and material cycles interact and communicate with the open ocean. This includes processes at the sediment-water interface, “memory effects” of past conditions on present status of ecosystems, land-sea fluxes of materials, processes that affect the functioning of the “continental shelf pump” for CO2, and the oxygen status. Especially intriguing is the hysteresis of the watershed-coastal ocean coupled system, which often delays the full manifestation of adverse as well as remedial effects, and, therefore, warrants special attention.

We invite contributions on the ecosystem and biogeochemical dynamics of continental margins, how they vary and how they may change in the future due to anthropogenic drivers, and how the changes may feedback to the climate system and threaten the livelihood of the large coastal human population. The session is aimed at promoting awareness of both natural and human-induced changes in continental margin ecosystems and the resulting potential hazards and long-term effects. The discussion is purported to assess threats from various anthropogenic changes imposed upon continental margins and to prioritize future research needs for better assessment. Since not all continental margins are the same, it is highly desirable to identify the most vulnerable continental margins and to specify different types of processes and interactions that are likely to play out on different types of continental margins. Last but not the least we also welcome contributions on how such trends may be checked or averted by regulatory measures.

Workshop 1 Conveners

Kay-Christian Emeis (Helmholtz Center Geesthacht, Germany)

Lisa Levin (Scripps Institution of Oceanography, USA)

Kon-Kee Liu (National Central University, Taiwan)

Wajih Naqvi (National Institute of Oceanography, India)

Mike Roman (Horn Point Laboratory, USA)

Workshop Presentations

DAY 1 - Monday 28 January

08:00-09:00 IMBIZO llI Registration

Welcome - Eileen Hofmann, Alida Bundy and Kon-Kee Liu


Workshop 1 Keynote presentation: Ocean hypoxia from physics to fish – Curtis Deutsch

10:00-10:45 Workshop 1 Keynote presentation: Nutrients, hypoxia and fisheries: lessons about multiple stressors from the Chesapeake and beyond – Denise Breitburg
10:45-11:15 Coffee break
11:15-12:00 Workshop 2 Keynote presentation: Microbial carbon pump and ecosystem connectivity – Farooq Azam

Workshop 3 Keynote presentation: “ADApT or Die”: Finding methodologies to secure the livelihoods and food security for fisheries dependent communities around the world – Moeniba Isaacs

12:45-13:45 Lunch

Workshop 1 overview and objectives - KK Liu and Kay Emeis

WS1_opening.pdf 744.73 kB

Session 1 - Chair: KK Liu

Ecosystem reponses to external forcings in continental margins


Drivers of change in estuarine-coastal ecosystems: Discoveries from four decades of study in San Francisco Bay, USA - James Cloern


Climate-induced ecosystem and biogeochemical shifts in the Cariaco Basin (Venezuela - southeastern Caribbean Sea) - Enrique Montes


Nutrient and phytoplankton responses to external forcing in a Mediterranean coastal area unbiased by terrestrial inputs and local activities (Calvi, Corsica) -Anne Goffart


Shelves of the Arctic Ocean: C flux and climate change - Paul Wassmann

15:30-16:00 Coffee break

Discussion 1 - Chair: Paul Wassmann, Rapporteur: Eileen Hofmann

How do biogeochemistry and ecosystems interact in response to climate change or human impacts in continental margins?


Plenary session discussion – Chair KK Liu, Rapporteur: Karen Wishner

How do biogeochemistry and ecosystems interact in response to natural or man-induced forcing in continental margins and how can such knowledge forge better management of the marine realm?

WS1_Day1.pdf 130.61 kB
18:00-19:30 Ice Breaker and poster session

DAY 2 - Tuesday 29 January


Session 2 - Chair: Karin Limburg

Human impacts on continental margins


The North Sea – A shelf sea in the anthropocene – Kay Emeis

Kay Emeis.pdf 3.36 MB

Role of episodic events in the transport and sequestration of terrestrial sediment in the Cariaco Basin – Laura Lorenzoni


Response of nutrient transports to human activities in the ecosystem of the Bohai Sea: Under the influence of artificial floods - Su Mei Liu

Su Mei Liu.pdf 2.13 MB

Eutrophication, nutrient imbalance, ecosystem disruptive algal blooms, and the algal biofuels agenda - Kevin Flynn

Kevin Flynn.pdf 2.33 MB
10:20-10:30 General discussion
10:30-11:00 Coffee break

The fate of Rhone River carbon on the Mediterranean continental margin, its export to the open sea and its relation to climatic parameters - Christophe Rabouille


Discussion 2 - Chair: Kay Emeis, Rapporteur: Lisa Levin

What are the characteristics of and early warning indicators for deviations from the regime of natural variability in continental margins due to human impacts?

12:30-13:30 Lunch

Session 3 - Chair: Kay Emeis

Biogeochemical reposes to climate change in continental margins


Denitrifying communities in oceanic oxygen deficient zones using microarray analyses - Amal Jayakumar


210Po/210Pb dynamics in relation to zooplankton biomass and trophic conditions during an annual cycle in northwestern Mediterranean coastal waters - Jaime Färber Lorda


Coastal Eastern Arabian Sea? A hotspot for production of nitrous oxide, methane and dimethyl sulphide - Damodar Shenoy


Massive nitrogen loss in the seasonal oxygen-deficient zone over the Western Indian - Amit Sarkar

Amit Sarkar.pdf 1.21 MB
14:50-15:00 General discussion
15:00-15:30 Coffee break

Discussion 3 - Chair: Curtis Deutsch, Rapporteur: Chuanlun Zhang

What are the biogeochemical feedbacks from ecosystem responses in continental margins to climate change?


Plenary session discussion – Chair: Helmuth Thomas

How may current understanding of deep ocean processes translate to better assessment and stewardship of fundamental ecological services that deep oceans provide?

WS1_Day2.pdf 510.35 kB
18:00-20:00 Poster session

 DAY 3 - Wednesday 30 January


Session 4 - Chair: KK Liu

Trends of warming-deoxygenation and their impacts


In search of the dead zone: Use of otoliths for tracking fish exposure to hypoxia -Karin Limburg


Trends in hypoxic conditions in the northern Adriatic Sea - Michele Giani


Biogeochemical and environment triggers as hypoxia inducers in the coastal Baltic Sea - Angela Caballero-Alfonso


Vulnerability of the Black Sea to human induced environmental pressures under present day conditions and a potential future climate scenario - Heather Cannaby

10:20-10:30 General discussion
10:30-11:00 Coffee break

Session 5 - Chair: Wajih Naqvi

Key processes in continental margin biogeochemical cycles


Si inputs to the world ocean: new insights from the Congo margin and deep sea fan - Olivier Ragueneau

11:20-11:40 Intra-annual variability of nutrient biogeochemistry in the shelf waters off Cochin, southeastern Arabian Sea - G.V.M. Gupta

Net anthropogenic nutrient inputs and nutrient fluxes from watersheds - Dennis Swaney


Atmospheric deposition of N, P and Fe to the northern Indian Ocean: Implications to surface ocean biogeochemistry – Manmohan Sarin

12:20-12:30 General discussion
12:30-13:30 Lunch

Session 6 - Chair: Denise Breitburg

Hypoxia and hypercapnia in upwelling systems

13:30-13:50 Hypoxia, hypercapnia and homosapiens on upwelling margins - Lisa Levin

The future evolution of multiple stressors in Eastern boundary - Zouhair Lachkar

14:10-14:30 Oxygen minimum zones, zooplankton layers, and global change - Karen Wishner

Impacts of seasonal hypoxia on the structure of phytoplankton and mesozooplankton in the water column of the eastern Arabian Sea - Mangesh Gauns

14:50-15:00 General discussion
15:00-15:30 Coffee break

Discussion 4 - Chair: Denise Breitburg

How do ecosystems respond to natural or man-induced forcing in continental margins?


Plenary session discussion – Chair: Alida Bundy

How can natural and social scientists optimize their cooperation to achieve usable and integrated knowledge and understanding to support policy making and form viable feedback loops between the natural system and human society?

WS1_Day3.pdf 207.89 kB
19:15-24:00 IMBIZO lll dinner – Hawaii Beach Restaurant

DAY 4 - Thursday 31 January


Session 7 - Chair: Lisa Levin

Interactions between natural and social sciences

09:00-10:30 Panel discussion: Human-ocean-human interactions with respect to global change (Workshops 1 and 3 Joint session)
10:30-11:00 Coffee break

A coupled model of economics, human behaviour, and bivalve biology: application to the surfclam fishery - Eileen Hofmann


Discussion 5 - Chair: Eileen Hofmann, Rapporteur: Karin Limburg

How can natural scientists provide useful knowledge for better management of continental margin ecosystems?

12:30-13:30 Lunch

Final plenary session

Summary reports from Workshops 1, 2 and 3 and plenary discussion sessions

15:00 Closing comments