Marine geologist Furu Mienis studies the carbon budget in the deep sea. ‘That budget is an important part of the current climate issue. I am studying several of the 6000 or so deep gorges or so-called submarine canyons found worldwide, such as the Whittard canyon off the coast of Ireland. These canyons which are similar in size as canyons on land like the Grand Canyon, are literally the ocean’s drains, connecting the shallow productive shelf areas with the food-deprived deep sea. Especially after heavy storms but also after the large-scale fishing on the continental slopes, a lot of material disappears via these canyons into the deep sea. Due to the turbulence in and around the deep gorges that cut across the slopes, material is deposited at the deepest point: the canyon floors.’
Part of the material that disappears into the deep sea via canyons literally consists of waste, such as plastics. However, I mainly examine the organic material, which predominantly consists of dead plankton. When plankton dies, they slowly sink to the bottom. Canyon processes can speed up this process resulting in a lot more carbon disappearing into the deep sea. If that organic material in the deep sea is subsequently buried it is removed from the carbon cycle, being a valuable part in the carbon budget. However, the high amounts of organic matter also form an important food source for fauna, which makes these canyon systems ecosystem hotspots in the deep sea.
‘Some of the organic material that disappears into the deep sea is re-used as food by other forms of life, such as deep-sea corals. These corals do not rely like their tropical counterparts on algal symbionts, but actively capture food particles from the water column with their tentacles. These deep-sea coral reefs are hotspots of biodiversity and biomass and provide important habitat for a lot of life, which is still partly unknown at present!’
‘Oceans are by far the largest reservoir of free carbon. The balance between carbon in the oceans, which is once again taken up in corals and other life, and carbon that is permanently removed from the cycle is, therefore, an extremely important part of the problem concerning CO2 emission and climate change.’
My research fits at the interplay between sedimentology, ecology and physical oceanography. It focuses on understanding environmental conditions and dynamics that influence the functioning of often vulnerable ecosystems in the deep sea (e.g. cold-water coral reefs, sponge grounds, canyons). I mainly focus on the identification of transport and (food) particle supply mechanisms to the deep-sea. Using benthic observatories I measure vertical and lateral particle supply and transport in the benthic boundary layer near deep-sea ecosystems. Subsequently, the knowledge of recent conditions is applied to reconstruct environmental conditions in the past using sediment cores.
Whereas it is clear that on geological timescales the marine carbon cycle controls global carbon partitioning and hence atmospheric pCO2, carbon fluxes within the marine domain remain poorly constrained. Although Earth System Models take into account vertical organic carbon fluxes in the ocean, lateral transport pathways are seriously understudied and therefore not included in such models. Multiple studies indicate that lateral transport actually plays a dominant role in organic matter fluxes from continental margins to the deep ocean. Most of this lateral transport is probably channelled through so-called submarine canyons, which provide effective connections between productive shelf waters and the nutrient-poor deep-sea. Moreover, submarine canyons not only provide effective conduits, but also their steep and irregular topography interacts with hydrography, resulting in enhanced turbulence and mixing that affects organic matter dispersal, remineralization and potentially even retention. The heterogeneity of canyons provides a multitude of habitats for deep-sea fauna, which play a significant role in remineralisation processes. These so far unquantified pathways urgently need to be constrained to provide crucial boundary conditions for Earth System Models, and hence better prediction of future climate change. Therefore, I here propose to establish a process based understanding of the role of submarine canyons in deep-sea carbon pathways, using a multidisciplinary approach. Deep-sea benthic observatories equipped with novel instruments will be deployed to capture physical processes that govern particle transport at all relevant time scales. Particle fluxes and biogeochemical properties will be determined to distinguish between fresh and refractory carbon. These will be related to community respiration of biodiversity hotpots within canyons to establish remineralisation rates. Especially in a fast changing world it is crucially important to understand transport, sequestration and remineralisation processes, as these underlay carbon fluxes between surface and deep ocean and hence potentially have both positive and negative feedbacks on climate change.
The objective of SponGES is to develop an integrated ecosystem-based approach to preserve and sustainably use vulnerable sponge ecosystems of the North Atlantic. The SponGES consortium, an international and interdisciplinary collaboration of research institutions, environmental non-governmental and intergovernmental organizations, will focus on one of the most diverse, ecologically and biologically important and vulnerable marine ecosystems of the deep-sea - sponge grounds – that to date have received very little research and conservation attention. Our approach will address the scope
and challenges of EC’s Blue Growth Call by strengthening the knowledge base, improving innovation, predicting changes, and providing decision support tools for management and sustainable use of marine resources. SponGES will fill knowledge gaps on vulnerable sponge ecosystems and provide guidelines for their preservation and sustainable exploitation. North Atlantic deep-sea sponge grounds will be mapped and characterized, and a geographical information system on sponge grounds will be developed to determine drivers of past and present distribution. Diversity, biogeographic and connectivity
patterns will be investigated through a genomic approach. Function of sponge ecosystems and the goods and services they provide, e.g. in habitat provision, bentho-pelagic coupling and biogeochemical cycling will be identified and quantified. This project will further unlock the potential of sponge grounds for innovative blue biotechnology namely towards drug discovery and tissue engineering. It will improve predictive capacities by quantifying threats related to fishing, climate change, and local disturbances. SpongeGES outputs will form the basis for modeling and predicting future ecosystem dynamics under environmental changes. SponGES will develop an adaptive ecosystem-based management plan that enables conservation
and good governance of these marine resources on regional and international levels.
More information about the project can be found at http://www.deepseasponges.org or follow us on facebook @deep-sea sponges
Artificial structures in the North Sea offer hard substrate to a rich and diverse epifauna in an area covered by soft sediment. The protected no-trawling zones around the offshore installations form a refuge for vulnerable soft sediment fauna. On basis of the high biomass of epifauna found on artificial structures, we hypothesize that this epifauna community acts as biofilter depleting primary organic matter in the water column while producing feaces, nutrients, dissolved organics, and propagules (larvae). In doing so the epifauna on the structures cast a “shadow” around the installation where physico-chemical conditions and the particle flux are altered. The altered particle flux in turn will have an effect on the benthic ecosystem around the installation. This effect will become less pronounced in deeper water due to general attenuation of the particle flux. Through production of propagules (larvae) the epifauna community contributes to persistence of rare and endangered species in the heavily trawled North Sea. To test our hypotheses, we aim to: 1) measure concentrations and fluxes of particles (organic matter, larvae) and solutes (nutrients, dissolved organic matter) around an offshore installation in a shallow vs deep setting, 2) measure impacts on the surrounding benthic community through community parameters (biomass, respiration), 3) model the “shadow” effect on the basis of observations and existing data, and 4) identify and quantify the production of propagules. Above will be accomplished by a combination of lab studies, short-term field studies, and long-term deployment of particle traps.
2012-2015 Postdoctoral Researcher Royal NIOZ
VENI-NWO - Cold-water coral ecosystems: carbon sinks in the deep sea and BOEM canyons project - Pathways to the abyss
Member of the executive organising committee of the 5th International Symposium on Deep-Sea Corals (ISDSC 5), which was held 1-6 April 2012, Amsterdam and guest editor Deep Sea Research II Special issue "Cold Corals" (Proceedings of ISDSC 5)
2010-2012 Post-doc at MARUM, Bremen University (research fellowship)
2008-2010: Post-doctoral researcher (NIOZ), Project MiCROSYSTEMS, Microbial Diversity and Functionality in Cold-Water Coral Reef Ecosystems
2003-2008: PhD-student (NIOZ) working on the MOUNDFORCE project, Environmental Constraints on Cold-water Coral Growth and Carbonate Mound Formation.
1998-2003: Study geology (M.Sc.) at the VU University (Vrije Universiteit) Amsterdam - with specialisation in sedimentology and environmental analysis.