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The sedimentology and micropalaeontological content of a core located in the Forua marsh of the Nature Reserve of the Urdaibai (Soutern Bay of Biscay) have been analysed in order to characterise the modem Holocene evolution of this marsh. Based upon lithology and benthic Foraminifera assemblages, five units have been identified in this core. The older one represents a subtidal, estuarine palaeoenvironment with marine influences, dated of 4640 years BP, that is, at the end of a transgressive phase initiated at about 5000 y BP, coincident to the Atlantic-Subboreal transition. During the second phase the sea retreated from the Urdaibai and a marsh settled in Forua at around 4500 y BP (end of Neolithic). The filling of this marsh is evidenced by changes of micropalaeontologic assemblages. A third sedimentologic phase is characterised in this area by a brackish marsh that is temporarily flooded with waters from the marine shelf. This event could be related to the transgressive pulsation occurred during the Subboreal-Subatlantic transition (3500-2500 y BP; early-mid Bronze Age). The sedimentary filling of the marsh was completed during the fourth episode, as evidenced by the exclusive occurrence of agglutinated species of Foraminifera typical of upper, vegetated marsh settlements. Calcareous microfauna disappear at the top of this core as a consequence of the total emergence of this area that became a polder used for culturing up to 7 960. The occurrence of few specimens of J. macrescens in the last centimetres of the core evidences the occasional flooding of this area during equinoccial tides

The sedimentology and micropalaeontological content of a core located in the Forua marsh of the Nature Reserve of the Urdaibai (Soutern Bay of Biscay) have been analysed in order to characterise the modem Holocene evolution of this marsh. Based upon lithology and benthic Foraminifera assemblages, five units have been identified in this core. The older one represents a subtidal, estuarine palaeoenvironment with marine influences, dated of 4640 years BP, that is, at the end of a transgressive phase initiated at about 5000 y BP, coincident to the Atlantic-Subboreal transition. During the second phase the sea retreated from the Urdaibai and a marsh settled in Forua at around 4500 y BP (end of Neolithic). The filling of this marsh is evidenced by changes of micropalaeontologic assemblages. A third sedimentologic phase is characterised in this area by a brackish marsh that is temporarily flooded with waters from the marine shelf. This event could be related to the transgressive pulsation occurred during the Subboreal-Subatlantic transition (3500-2500 y BP; early-mid Bronze Age). The sedimentary filling of the marsh was completed during the fourth episode, as evidenced by the exclusive occurrence of agglutinated species of Foraminifera typical of upper, vegetated marsh settlements. Calcareous microfauna disappear at the top of this core as a consequence of the total emergence of this area that became a polder used for culturing up to 7 960. The occurrence of few specimens of J. macrescens in the last centimetres of the core evidences the occasional flooding of this area during equinoccial tides

The microfauna (foraminifers, ostracods) and sedimentology of a core from the supratidal polluted area of the Ria of Gernika (S of Bay of Biscay) have been analysed in this work. Four different episodes have been recognised in the last 6400 years in this area, based upon microfaunaI assemblages and sedimentological facies. The older one represents a subtidal palaeoenvironment with marine influences at the base of this core. A subsequent increase of the energy in a tidal palaeoenvironment is evidenced by the occurrence of rhythmic fades and estuarine characteristic microfaunaI assemblages. This level is correlated to transgressive pulsations previously described in the Bay of Biscay 3500 to 2500 y. BP. Third episode shows a progressive shallowing of the palaeoenvironment, with low-salinity and mixed waters in a supratidal marshy milieu. To the core top, a very fine sediment with abundant plant roots and very scarce microfauna indicate the present filling of this part of the estuary

The sedimentology and micropaleontological content (benthic foraminifera) of a core located in the Anbeko polder of the Urdaibai estuary (Southern Bay of Biscay) have been analysed in order to characterize the holocene evolution of this polder. Based upon sedimentology and micropalaeontological assemblages, four units have been identified in this core. During the first phase this area was under marine conditions, with a a maximum marine influence around 5000 years BP. The pulsation described during the Atlantic-Subboreal transition of the Holocene is then registered in this core. Sedimentological facies of the second unit indicate a decrease of energy in this environment, where outer estuarine foraminifera dominated the assemblages. The third phase indicates the progressive filling of the estuary, with the appearance of a vegetated marsh, as evidenced by the total dominance of agglutinated foraminifera. This marsh, which is progressively isolated from the tidal influence, was anthropologically transformed into a polder during the 1 8th. century

The microfauna (foraminifers, ostracods) and sedimentology of a core from the supratidal polluted area of the Ria of Gernika (S of Bay of Biscay) have been analysed in this work. Four different episodes have been recognised in the last 6400 years in this area, based upon microfaunaI assemblages and sedimentological facies. The older one represents a subtidal palaeoenvironment with marine influences at the base of this core. A subsequent increase of the energy in a tidal palaeoenvironment is evidenced by the occurrence of rhythmic fades and estuarine characteristic microfaunaI assemblages. This level is correlated to transgressive pulsations previously described in the Bay of Biscay 3500 to 2500 y. BP. Third episode shows a progressive shallowing of the palaeoenvironment, with low-salinity and mixed waters in a supratidal marshy milieu. To the core top, a very fine sediment with abundant plant roots and very scarce microfauna indicate the present filling of this part of the estuary

The sedimentology and micropaleontological content (benthic foraminifera) of a core located in the Anbeko polder of the Urdaibai estuary (Southern Bay of Biscay) have been analysed in order to characterize the holocene evolution of this polder. Based upon sedimentology and micropalaeontological assemblages, four units have been identified in this core. During the first phase this area was under marine conditions, with a a maximum marine influence around 5000 years BP. The pulsation described during the Atlantic-Subboreal transition of the Holocene is then registered in this core. Sedimentological facies of the second unit indicate a decrease of energy in this environment, where outer estuarine foraminifera dominated the assemblages. The third phase indicates the progressive filling of the estuary, with the appearance of a vegetated marsh, as evidenced by the total dominance of agglutinated foraminifera. This marsh, which is progressively isolated from the tidal influence, was anthropologically transformed into a polder during the 1 8th. century

Since the begining of the ECOMARGE (Program France -JGOFS), one of the most important questions addressed has been the transfer o f p a rticula te m a tte r over the shelf-break downon the slope and in to the deep sea. Several inorganic markers, such as quartz sand and detrital heavy mineral suites, were used to demonstrate the importance of shelf spill-over process. Biogenic markers were also considered. Downslope transport of shallow-water benthic foram iniferais a common phenomenon; hence, the study of displayed middle and outer shelf benthic foraminifera present in the slope cores provides good information about pathways of sediment transport such as submarine canyon. B en thicforamin ife ra l assemblages from the continental slope in the Cap-Ferret Canyon area yielded autochthonous populations from the upper bathyal, mid bathyal and lower bathyal zones. Transported fauna from the sublittoral and circalittoral zones were also found in the Cayon. They indicate a continuous input of material into the Canyon via the slope channels, particularly ip the southern and northern axis

Since the begining of the ECOMARGE (Program France -JGOFS), one of the most important questions addressed has been the transfer o f p a rticula te m a tte r over the shelf-break downon the slope and in to the deep sea. Several inorganic markers, such as quartz sand and detrital heavy mineral suites, were used to demonstrate the importance of shelf spill-over process. Biogenic markers were also considered. Downslope transport of shallow-water benthic foram iniferais a common phenomenon; hence, the study of displayed middle and outer shelf benthic foraminifera present in the slope cores provides good information about pathways of sediment transport such as submarine canyon. B en thicforamin ife ra l assemblages from the continental slope in the Cap-Ferret Canyon area yielded autochthonous populations from the upper bathyal, mid bathyal and lower bathyal zones. Transported fauna from the sublittoral and circalittoral zones were also found in the Cayon. They indicate a continuous input of material into the Canyon via the slope channels, particularly ip the southern and northern axis