|DeepForams - Deepsea foraminifera from the Portuguese Margin|
Ana Aranda da Silva
Programme - PTDC/MAR/110082/2009
Execution dates - 2011-04-01 - 2014-03-31 (36 Months)
Funding Entity - Fundação para a Ciência e a Tecnologia e Compete
Funding for CESAM - 113372 €
Total Funding - 175460 €
Proponent Institution - Universidade de Aveiro
Laboratório Nacional de Energia e Geologia, I.P.
Rua da Amieira, Apartado 1089
4465-021SÃO MAMEDE DE INFESTA
Molecular Systematics Group (MSG)
Department of Zoology and Animal Biology, University of Geneva
30, Quai Ernest Ansermet 1211 4GENEVA
National Oceanography Centre (NOC)
SO14 3Z SOUTHAMPTON
Foraminifera are protists that that often dominate modern deep-sea benthic communities. Hard-shelled species have an outstanding fossil record and are widely used to reconstruct past environments based on living species. The non-chemosynthetic deep-sea relies on phytodetritus reaching the seabed as food source, and foraminifera are at the base of the food-chain, feeding selectively and reworking the organic matter before higher trophic consumers. Consequently, foraminifera play an important role in carbon cycling, and by studying the biology of foraminifera, we may better understand how they contribute to the carbon budget with consequences in regulating the climate.
Although foraminifera are amongst the most important groups of deep-sea benthic organisms, one important faunal component, the soft-shelled species are often overlooked, although they can represent 1/5th of the total foraminiferal abundance and diversity in the deep-sea. The study of these organisms may reveal interesting findings as recently shown, these organisms to be able to withstand high CO2 levels, being likely survivors of a high CO2 world . Another recent find shows gromiid traces (another soft-shelled protist closely related to foraminifera) on the deep-sea that may question the early origin of metazoans .
Within foraminiferal work, calcareous species (Rotaliids) are well studied at the morphological and molecular level forming a natural phylogenetic group that appeared more recently on the earth´s history. On the other hand, the study of monothalamous, agglutinated and organic-walled deep-sea foraminifera is still in its infancy . They do not seem to constitute a natural phyogenetic group at the molecular level, but compared to the potential number of existing species, we have very little number of sequences . By adding more sequences to the existing database will improve the phylogenetic analysis and we can try to better understand the evolution of early foraminifera.
The Portuguese margin has a seasonal upwelling contributing to an organic enrichment on the seabed, enhanced within the canyons that cross the margin. The DeepForams project aims to study deep-sea benthic foraminifera from the Portuguese margin, within the canyons and on the adjacent slopes. Some of the project partners are members of HERMIONE, a EU project that has the Portuguese canyons as one of the research study areas .
First we will characterize benthic foraminiferal communities inhabiting the Portuguese margin canyons (Nazaré and Setúbal) and adjacent slopes, including the soft-shelled species. Replication will be done so patchiness can be assessed and results can be directly compared to faunal studies. Published data from HERMES on meiofauna, macrofauna and megafauna metazoan, is available so we can compare how protists respond to environmental gradients when compared to metazoan. It is important to find biological patterns between organisms that may correlate to organisms that have fossil potential such as hard-shelled foraminifera in order to understand potential fossil assemblages.
Specific objectives are to:
• Analyse the abundance, taxonomic composition, diversity, vertical distribution and live:dead ratios of foraminiferal assemblages (including soft-shelled species) in samples from the Nazaré and Setúbal canyons and adjacent slope areas using morphological criteria;
• Compare foraminifera and metazoan responses to contrasting environmental conditions in the canyons and on the slope.
Alongside the faunal work, we will assess the phylogeny of the most common species from the canyons and adjacent slope, with particular focus on the soft-shelled foraminifera. We will also sequence soft-shelled species from around the world, so we can try and resolve the molecular phylogeny of foraminifera as a group within the Rhizaria.
Specific objectives are to:
• Analyse DNA gene sequences from common species found in Portuguese margin;
• Increase the existing database on soft-shelled foraminifera and to better understand the evolution of early foraminifera.
One very interesting group of foraminifera found in the Portuguese canyon and areas of enhanced organic matter is the Xenophyophora . These are confined to the deep-sea and little is still known about their biology. Several questions regarding this group of organisms will be addressed during this project:
• What is the eukaryote molecular composition of xenophyophores?
• Are the eukaryote inhabitants of these organisms the same as the surrounding sediments?
• Do xenophyophores increase the eukaryote diversity and abundance of deep-sea sediments?
• Are they important in maintaining biodiversity of eukaryote organisms in the deepsea?
• What are the bacterial symbionts associated with particular xenophyophore?
• What is the role of bacterial endo-symbionts on their nutrition?