Deep water sponges: ecological importance
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Deep water sponges: ecological importance and threats to their functioning Bannister RJ, Kutti T, Fosså JH Havforskningsinstittutet Outline • Background – What are sponges? – Ecological importance? – How do sponges function? – Responses to the ecosystem – Sponges in Norway • Sponge research at IMR – Ecology » Ecological importance – Basic biology – Physiological stress to suspended sediments • The future What are sponges? • Sponges (Porifera) are the least evolutionarily advanced group of the animal kingdom – Approx. 16,000 spp. • 4 different classes – Distributed globally • • • • Tropical coral reefs Temperate rocky shores Deep-sea polar habitats Hydrothermal vents Importance of sponges Ecologically • Functional components of benthic ecosystems (Bell 2008) • Nutrient recycling and mineralisation of carbon & nitrogen • Provide food source • Provide shelter/refuge • Provide habitat • Provide structural resilience to reefs How do they function? Diverse group of filter feeders Simplistic body plan – No true tissues or organs – System of water canals – Specialised cells • Feeding • Respiration • Reproduction • Spicule production • Chemical defense How do they function? Feeding – Highly efficient filter feeders • Up to 24 000 L water daily per kg of tissue – Diverse nutritional demands • Phytoplankton • Picoplanton • Bacteria and viruses – Symbiotic community • • • • • DON & DOC Photosynthesis Nitrogen fixation Methanogenesis Sulphate reduction microvilli Choanocyte - the pump & filter How do they function? Responses to their ecosystem? Environmental – Sediment • Deposited & suspended • Organic & inorganic • Polluted & unpolluted – Substrate • Type & slope – Exposure • Current velocities • Wave exposures – Food availability – Temperature, salinity & acidification Biological – Competition & predation Photo: IMR Sponges in Norway • >300 different sponge species – Mass sponge aggregations • Astrophorida • Axinellida • Poecilosclerida – Geodia sp. sponges most dominant • Fjords • Shelf (Norwegian Sea) • Shelf (Barents Sea) • Importance of sponges to Norwegian ecosystem? Photo: IMR Photo: IMR Research focus at IMR Increase basic knowledge on deep water sponges • Ecology – Distribution and abundance? • Biology and Physiology – How do deep water sponges function? • Feeding • Pumping • Respiration • Responses to anthropogenic changes – How do sponges cope with suspended sediment • Mining & oil drilling • Trawling • Aquaculture Træna Deep cold-water coral MPA Træna Deep cold-water coral MPA 14 towed underwater video transects á 2 km split into 6 sub-transects 3 of the 6 sub-transects selected still photos (á 9 m2) taken every 30 s large-sized sponges identified (and measured) 3.0 Træna Deep cold-water coral MPA Oceanapia Asconema type Aplysilla G macandrewii Isops Mycale Stryphnus G. barretti 3 different types of sponge communities were identified Western side of depression dominated by G. barretti, G. atlantica & G macandrewii G. atlantica Mean biomass 2.4 kg m-2 Phakellia Stelletta -1.5 Antho -1.0 3.0 Photo: IMR 3.0 Træna Deep cold-water coral MPA Oceanapia Asconema type Aplysilla G macandrewii Isops Mycale Stryphnus G. barretti G. atlantica Phakellia 3 different types of sponge communities were identified The eastern side of the depression dominated by fan-shaped Phakellia sp. sponges and further characterized by Oceanapia and Mycale sponges. Stelletta -1.5 Antho -1.0 3.0 Photo: IMR 3.0 Træna Deep cold-water coral MPA Oceanapia Asconema type Aplysilla G macandrewii Isops Mycale Stryphnus G. barretti G. atlantica Phakellia Stelletta -1.5 Antho -1.0 3.0 3 different types of sponge communities were identified On both sides of the depression in areas with a high density of cold water corals the community was characterized by Geodia spp. Mycale & Oceanapia spp. Træna Deep cold-water coral MPA In the Træna Deep we found a mean of 1 sponge m-2 All area can be characterized as sponge ground Massive biomass – what´s the ecological function? Biology & Physiology • 3D reconstruction of the canal system of G.barretti – Measure the canal and feeding chamber dimensions – Frictional losses with water flow within a sponge – Establish model for pumping activity • Measuring the pumping activity of G.barretti – Pumping speed (cm s-1) –Up to 13 cm s-1 – Pumping volume (L) – Up to 1000 L kg tissue d-1 – Behaviour –Constant pumping activity Biology & Physiology Feeding chambers Canal system Bacteria Feeding cells Biology & Physiology • Feeding biology – What do cold deep-water sponges feed on? –Bacteria Microvilli Flaggella –TOC & DOC Gasket –Nutrients –NO2 –NO3 –NH4+ –Si –PO4 Sediment interactions on deepwater sponges • How does suspended sediments affect deep-water sponges? •Oil drilling operations (NRC) •Mine dumping •Aquaculture effluent Particle size, shape, conc, and composition Sediment interactions on deepwater sponges • How do suspended sediments affect deep-water sponges? •Population level •Distribution and abundance •Individual level •Physiology, energetics, reproduction •Cellular level •Mucus production, cell death, cell viability, DNA damage •Molecular level •Gene expression and metabolomics Sediment stress on deep-water sponges • Exposure experiments • 12 hr exposure experiments (0, 10, 50, 100 mg/L) • Natural sediment, bentonite & barite • Physiological changes • Cellular and molecular responses • 14 day exposure experiments (10 and 30 mg/L) • Chronic (constant exposure) • Cyclic (12h on / 12h off) Sediment stress of deep-water sponges Sediment stress of deep-water sponges Microvilli Conclusions/Questions • Ecologically important – Dominate the benthic shelf system (high biomass) – Benthic pelagic coupling • Filtering particulate/dissolved carbon and nitrogen • Converting this to waste by-products for other organisms • Rapid pumping response to suspended sediment loads – Concentration and particle type dependant • Acute and long term exposures to barite cause cellular damage in sponges Conclusions/Questions • Lysosomal membrane stability is a useful tool for monitoring effects of anthropogenic stressors in sponges • What is the energetic cost for sponges living under suboptimal conditions? – Reproduction? – Growth? – Population structure? • What impact will a loss of sponge biomass on the shelf mean for the functioning of the ecosystem? Sponge research team • Sponge team at IMR – – – – Raymond Bannister Tina Kutti Jan Helge Fosså Cathinka Krogness • SINTEF • Canada • Australia • Denmark • Netherlands Acknowledgements • Research council of Norway – RESPONSE and SEDEXSPONGE project • Technical team at IMR • Crew onboard RV Håkon Mosby • Statoil - supply of drilling muds Continental shelf research Vol. 69, 21-30 (2013) Aquatic Biology Vol. 19, 65-73 (2013)
