CESAM (Centre for Environmental and Marine Studies) & Department of Biology

University of Aveiro, Portugal

The bathyal domain, extending between the continental shelves and the abyssal plains, is biologically and structurally heterogeneous and includes a vast diversity of fragmented habitats in the continental slopes and in other relevant topographic features such as ocean ridges and seamounts. Examples of these habitats, usually thought as “biodiversity hotspots”, are the canyons, cold seeps and cold-water coral reefs in continental margins and hydrothermal vents in ocean ridges. Bathyal ecosystems are strongly physically mediated and associated with dynamic geological or hydrological features and their faunal assemblages are characterized by high productivity, special physiological adaptations and apparent high endemicity. These ecosystems are likely to be biologically fragile, relevant to carbon cycling and susceptible to catastrophic events and global change; they are usually of difficult access and thus insufficiently studied but nevertheless subjected to a growing anthropogenic pressure.

Figure 1. Benthic fauna from bathyal environments: glaciar drop stones, carbonate chimneys, seamount, cold-water coral, mud volcano, hydrothermal vent, canyon.

Biological research on bathyal ecosystems was fostered by Prof. L. Pinheiro (CESAM & Department of Geosciences) and started in 2000 with the participation in the yearly TTR cruises (Training Through Research, IOC-UNESCO), developing in 2005 to a participation in the EU-funded project HERMES (www.eu-hermes.net). Since 2000 we participated in 13 cruises and collected hundreds of samples yielding a few thousands of invertebrate species. Several new or little known species (11 new and 3 little known), mainly from the hydrothermal vents of Lucky Strike, were illustrated and described in a number of papers but many others from the Gulf of Cadiz mud volcanoes and Portuguese canyons are in preparation or awaiting further attention. Noteworthy is the discovery of several undescribed bivalves and siboglinid polychaetes with an important role on chemosynthetic production in the Gulf of Cadiz. Ongoing studies include both morphological and molecular characterization (COI, S16, S18, S28) for a broader understanding of biogeographic and evolutionary patterns.

Figure 2. Examples of recently described species: Heteromesus ctenobasius Cunha & Wilson, 2006, and Obesutanais sigridi Larsen et al., 2006, from Lucky Strike, Tubiclavoides striatum Moura et al. (in press) and a Calianassid decapod (Dworshak & Cunha, submitted) from the Gulf of Cadiz.

Besides biodiversity, other studies aim a better knowledge of ecosystem functioning with a special focus on trophic relationships and endosymbiosis. Our first results on stable isotopes (d¹³C, d¹⁵N, d³⁴S) are indicative of the importance of chemosynthetic production in the mud volcanoes’ benthic food web and suggest thiotrophic symbioses in several invertebrate hosts. Molecular identification of chemosynthetic prokaryotic endosymbionts associated with bivalves from mud volcanoes was carried out using PCR-DGGE analysis of bacterial and archaeal 16S rRNA. The results suggest that these bivalves contain a diverse range of endosymbionts, including sulphur-oxidizer related bacteria. Further investigation is being carried out using bacterial and archaeal clone libraries to evaluate their full diversity and role in bivalve nutrition.

Figure 3. Examples of chemosynthetic species (siboglinid polychaetes and bivalves).

Selected publications:

1. Moura, C.J., M.R. Cunha, P. Schuchert (in press) J.Mar. Biol. Assoc., UK, 87.

2. Cunha, M.R., G.D.F. Wilson (2006) Zootaxa 1192: 1-76.

3. Larsen .K, M Blazewicz-Paszkowycz, M.R. Cunha (2006) Zootaxa 1187: 1-36.

4. Myers, A.A., M.R. Cunha (2004) J.Mar. Biol. Assoc. UK 84 (5): 1019-1025.

5. Cunha, M.R., GDF Wilson (2003) Zootaxa 326: 1-16.

6. Pinheiro, L.M., M.K. Ivanov, A. Sautkin, G. Akhmanov, V.H. Magalhães, A. Volkonskaya, J.H. Monteiro, L. Somoza, J. Gardner, N. Hamouni, M.R. Cunha (2003) Mar. Geol. 195: 131-151.

Marina R. Cunha started her academic career at the University of Aveiro in 1986, was appointed Assistant in 1991 and Auxiliary Professor in 2000 (current position) when she obtained a PhD degree in Biology. She is curator of the Biological Research Collection of Marine Invertebrates and researcher of the Marine Ecosystems and Modelling group at CESAM in the scientific domains of benthic ecology (analysis and interpretation of community data; biodiversity, community structure and trophic relationships; colonization and succession) and crustacean biology (taxonomy, population dynamics, life history and production). Her early research interests, focused on estuarine and coastal ecosystems, were redirected since 2000 to the study of biodiversity and functioning of bathyal ecosystems. Marina Cunha co-authored 15 SCI papers, contributed to the “Handbook of deep-sea hydrothermal vent fauna”, was Guest Editor of two publications, and refereed papers in 12 SCI journals in the field of and marine ecology and biology. She is Primary Consultant of CoMARGE - Census of Marine Life, and Secretary of the Executive Committee of the European Marine Biology Symposium.

The HERMES-UA team is a group of young researchers developing several projects focused on:

Gulf of Cadiz cold seeps: Ana Hilário (Post-Doc; Ecology of Siboglinidae); Ascensão Ravara (PhD student, Polychaete taxonomy), Clara Rodrigues (PhD student; Benthic assemblages, trophic structure and endosymbiosis); Joana Matzen (PhD student; Molecular evolution of Crustacea); Luciana Génio (PhD student; Evolutionary history and systematics of molluscs).

Portuguese canyons: Ana Aranda da Silva (Post-Doc; Benthic foraminiferal communities); Teresa Amaro (Post-Doc; Trophic ecology of key species); Dário Alves (PhD student; Biodiversity and structure of benthic assemblages at deep-sea chemosynthetic sites based on shell microstructure.