Eastern North Atlantic Region Research Articles

Feeding Habits of European Hake, <I>Merluccius Merluccius</I> (Actinopterygii: Gadiformes: Merlucciidae), from the Northeastern Mediterranean Sea

European hake, Merluccius merluccius (Linnaeus, 1758), is an important predator of deep Mediterranean upper shelf slope communities, being a nektobenthic species inhabiting a wide depth range (20–1000 m) throughout the Mediterranean Sea and the northeastern Atlantic region (Carpentieri et al. 2005). It is one of the chief commercial and most heavily exploited species of demersal fishery in all northern Mediterranean countries. Recent time-series studies referring to the western part of the Adriatic Sea have shown catches to be made up mainly of specimens shorter than 20 cm TL, with survey catch rates apparently increasing between 1985 and 1995 and decreasing in the following years both in the northern(Piccinetti and Piccinetti Manfrin 1971, Manfrin et al. 1998) and southern Adriatic Sea (Marano et al. 1998). In 2006, annual hake landings were estimated to be around 76 000 t in the Mediterranean (Anonymous 2008) and around 18 000 t in the Adriatic Sea (Anonymous 2007), with the species being the most abundant in the demersal group of the Adriatic Sea (Ungaro et al. 2001). As a rule, hake feeds predominantly on fish and crustaceans, and the proportion of piscivory increases with hake length; crustaceans appearing mostly in the stomach of <16 cm hakes in the northern-central Adriatic Sea (Karlovac 1959, Županovic 1968, Piccinetti and Piccinetti Manfrin 1971, Jukic 1972, Froglia 1973, Jardas 1976). The presently reported study analysed the diet of the hake in the northeast Mediterranean, which, given its abundance, plays an important role in comprehending the food chain dynamics. Despite hake’s environmental and economic importance (Oliver and Massuti 1995) in the Mediterranean, much of its ACTA ICHTHYOLOGICA ET PISCATORIA (2011) 41 (4): 277–284 DOI: 10.3750/AIP2011.41.4.03

Objective identification of synoptic meteorological patterns favouring African dust intrusions into the marine boundary layer of the subtropical eastern north Atlantic region

Synoptic geopotential height anomalies patterns favouring African dust outbreaks into the marine boundary layer (MBL) of the subtropical Eastern North Atlantic Region (SENAR) were objectively identified. The proportion of the total variance explained by each of these patterns was also calculated. Dust intrusions into the MBL of the SENAR were identified using total suspended particles (TSP) data at a rural background station in Tenerife Island (El Rio station, ER). Geopotential height anomalies at 1,000, 850, 700 and 500 hPa, respectively, in days of African dust intrusion in the period 1998–2003 were grouped in monthly sets. Two different but complementary methods (K-means and Principal Components) were applied to daily geopotential height anomalies for each month and for each pressure level in case of African dust intrusion. Three principal geopotential height anomalies patterns were found. Type I consist on a high-pressure system over Europe that affects North Africa, occasionally giving rise to a ridge. The Canary Islands are in the south-west flank of this high-pressure system. This pattern is dominant throughout the whole year. Type II and type III patterns consist on a low located to the northeast and southeast of the Canary Islands, respectively, coupled with a high over the Mediterranean basin and/or North Africa. Two case analyses are presented, as well as a systematic validation of the meteorological pattern classification for all dust intrusions detected at ER station within the period 2004–2007.

Trend changes of African airmass intrusions in the marine boundary layer over the subtropical Eastern North Atlantic region in winter

Trend changes of African airmass intrusions in the marine boundary layer over the subtropical Eastern North Atlantic region in winter

Trend changes of African airmass intrusions in the marine boundary layer over the subtropical Eastern North Atlantic region in winter

African dust intrusions in the marine mixing layer of the Eastern North Atlantic subtropical region (23.5°N to 35°N) are favoured in winter when the eastern edge of the Azores High covers Southwestern Europe and North Africa. In situ ground pressure observations and reanalysis from National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) and European Centre for Medium-Range Weather Forecasts (ECMWF) indicate that the Azores High has strengthened and shifted eastward in winter over the last three decades. This is evidenced by the increase over time of the Madrid–Tenerife Index which is defined as the geopotential height anomaly difference at 1000 mb between Tenerife (28.5°N; 16.3°W) and Madrid (40.5°N; 3.5°W) in winter and of the African Index which is defined as the residence time over Africa of air mass trajectories entering the subtropical Eastern North Atlantic Ocean. Barcelona Supercomputing Center/Dust Regional Atmospheric Model (BSC-DREAM) dust regional model simulations from 1958 to 2006 were performed, assuming that the soil characteristics of dust sources remained unchanged over time. Simulated winter dust concentration levels are well correlated (0.67) with the available background observations for the 1998–2004 period. The model results show a two-fold increase in winter dust concentrations over the 1980–2006 period with respect to the 1958–1979 period, corresponding to the strengthening and eastward shift of the Azores High. DOI: 10.1111/j.1600-0889.2010.00524.x

Trend changes of African airmass intrusions in the marine boundary layer over the subtropical Eastern North Atlantic region in winter

African dust intrusions in the marine mixing layer of the Eastern North Atlantic subtropical region (23.5°N to 35°N) are favoured in winter when the eastern edge of the Azores High covers Southwestern Europe and North Africa. In situ ground pressure observations and reanalysis from National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) and European Centre forMedium-RangeWeather Forecasts (ECMWF) indicate that the Azores High has strengthened and shifted eastward in winter over the last three decades. This is evidenced by the increase over time of the Madrid.Tenerife Index which is defined as the geopotential height anomaly difference at 1000 mb between Tenerife (28.5°N; 16.3°W) and Madrid (40.5°N; 3.5°W) in winter and of the African Index which is defined as the residence time over Africa of air mass trajectories entering the subtropical Eastern North Atlantic Ocean. Barcelona Supercomputing Center/Dust Regional AtmosphericModel (BSC-DREAM) dust regional model simulations from 1958 to 2006 were performed, assuming that the soil characteristics of dust sources remained unchanged over time. Simulated winter dust concentration levels are well correlated (0.67) with the available background observations for the 1998-2004 period. The model results show a two-fold increase in winter dust concentrations over the 1980-2006 period with respect to the 1958-1979 period, corresponding to the strengthening and eastward shift of the Azores High.

Boreal winter predictions with the GEOS-2 GCM: The role of boundary forcing and initial conditions

Ensembles of atmospheric General Circulation Model (GCM) seasonal forecasts and long-term simulations (1980-94) are analyzed to assess the controlling influences of boundary forcing and memory of the initial conditions. Both the forecasts and simulations are carried out with version 2 of the Goddard Earth Observing System (GEOS-2) GCM forced with observed sea surface temperatures (SSTs). While much of the focus is on the seasonal time scale (January- March) and the Pacific North American (PNA) region, we also present results for other regions, shorter time scales, and other known modes of variability in the northern hemisphere extratropics. Forecasts of indices of some of the key large-scale modes of variability show that there is considerable variability in skill between different regions of the Northern Hemisphere. The eastern North Atlantic region has the poorest long lead forecast skill showing no skill beyond about 10 days. Skillful seasonal forecasts are primarily confined to the wave-like ENSO response emanating from the tropical Pacific. In the Northern Hemisphere, this is associated with the well-known Pacific/North American (PNA) pattern. Memory of the initial conditions is the major factor leading to skillful extratropical forecasts of lead time less than one month, while SST forcing is the only factor at the seasonal time scale. SST forcing contributes to skillful forecasts at sub- seasonal time scales only over the PNA region. The GEOS-2 GCM produces average (1980-94) signal to noise ratios which are less than one everywhere in the extratropics, except for the subtropical Pacific where they approach 1.5. When confined to the ENSO years, the maximum signal to noise ratios occur in the PNA region where they exceed three. An assessment of the sampling distribution of the forecasts suggests the model's ENSO response is very likely too weak. These results show some sensitivity to the uncertainties in the estimates of the SST forcing fields. In the North Pacific region, the sensitivity to SST forcing manifests itself primarily as changes in the variability of the PNA response, underscoring the need for an ensemble approach to the seasonal prediction problem.

Atmospheric modes influence on Iberian Poleward Current variability

The inter-annual variability of the Iberian Poleward Current (IPC) along the northwestern coast of the Iberian Peninsula (IP) (40–43°N) and its intrusion in the Cantabrian Sea (Navidad, 6–8°W) were analyzed in terms of the atmospheric forcing. The January Sea Surface Temperature (J SST) was obtained from the advanced very high resolution radiometer (AVHRR) NOAA satellite from 1985 to 2006. It is a well documented fact that the existence of a tongue of water warmer than the surrounding ones (IPC) which circulates along the western Iberian shelf edge, turn eastward around Cape Finisterre, and enters in the Cantabrian Sea generating Navidad at the beginning of every winter. However, in the present study it has been highlighted that there are several years (1986, 1987, 1992, 1997, 1999, 2004 and 2005) during which water from coast to the adjacent shelf is much colder than the oceanic one remarking a weak or inexistent IPC during these Januaries. In addition, the dependence of SST on the most representative regional patterns with some influence upon the eastern North Atlantic region was analyzed by means of correlations between November–December atmospheric modes and J SST. The considered modes were: North Atlantic Oscillation pattern (NAO), Eastern Atlantic pattern (EA), Eastern Atlantic Western Russia pattern (EA/WR), Polar/Eurasia pattern (POL) and Scandinavia pattern (SCA). This analysis reveals that two atmospheric patterns (N-D NAO and N-D EA/WR) are responsible of the main variability of the J SST of the western and northern IP. J SST is negatively correlated with N-D NAO and positively correlated with N-D EA/WR. Multivariate analysis involving both modes provides correlation coefficients on the order of 0.7 on both coasts (western and northern). The influence of both modes on J SST was observed to be on the same order of magnitude but with different sign. These correlations were physically interpreted by means of an analysis of extreme events and Sea Level Pressure (SLP) composite analysis.

Genetic population structure of European sprat Sprattus sprattus: differentiation across a steep environmental gradient in a small pelagic fish

Factors such as oceanographic retention, isolation by distance and secondary contact zones have, among others, been suggested to explain the low, but statistically significant, neutral pop- ulation structure observed in many marine fishes. European sprat Sprattus sprattus L. is not known to display philopatric spawning behaviour or to exhibit local retention of eggs and larvae. It thus consti- tutes a good model for studying population structure in a characteristic small pelagic fish with high dis- persal potential and an opportunistic life history. We analysed 931 specimens of sprat from 9 spawning locations in and around the North Sea and Baltic Sea area and from a geographically distant popula- tion from the Adriatic Sea. Analyses of 9 microsatellite loci revealed a sharp genetic division separat- ing samples from the northeastern Atlantic Ocean and the Baltic Sea (pairwise θ = 0.019 to 0.035), con- curring with a steep salinity gradient. We found, at most, weak structure among samples within the northeastern Atlantic region and within the Baltic Sea (pairwise θ = 0.001 to 0.009). The Adriatic Sea population was highly differentiated from all northern samples (pairwise θ = 0.071 to 0.092). Overall, the observed population structure resembles that of most other marine fishes studied in the North and Baltic Sea areas. Nevertheless, spatially explicit differences are observed among species, probably reflecting specific life histories. Such fine-scale population structures should be taken into account when considering complex ecosystem functions, e.g. in multispecies stock management.

Are there connections between the Earth's magnetic field and climate?

Understanding climate change is an active topic of research. Much of the observed increase in global surface temperature over the past 150 years occurred prior to the 1940s and after the 1980s. The main causes invoked are solar variability, changes in atmospheric greenhouse gas content or sulfur due to natural or anthropogenic action, or internal variability of the coupled ocean–atmosphere system. Magnetism has seldom been invoked, and evidence for connections between climate and magnetic field variations have received little attention. We review evidence for correlations which could suggest such (causal or non-causal) connections at various time scales (recent secular variation ∼ 10–100 yr, historical and archeomagnetic change ∼ 100–5000 yr, and excursions and reversals ∼ 10 3–10 6 yr), and attempt to suggest mechanisms. Evidence for correlations, which invoke Milankovic forcing in the core, either directly or through changes in ice distribution and moments of inertia of the Earth, is still tenuous. Correlation between decadal changes in amplitude of geomagnetic variations of external origin, solar irradiance and global temperature is stronger. It suggests that solar irradiance could have been a major forcing function of climate until the mid-1980s, when “anomalous” warming becomes apparent. The most intriguing feature may be the recently proposed archeomagnetic jerks, i.e. fairly abrupt (∼ 100 yr long) geomagnetic field variations found at irregular intervals over the past few millennia, using the archeological record from Europe to the Middle East. These seem to correlate with significant climatic events in the eastern North Atlantic region. A proposed mechanism involves variations in the geometry of the geomagnetic field (f.i. tilt of the dipole to lower latitudes), resulting in enhanced cosmic-ray induced nucleation of clouds. No forcing factor, be it changes in CO 2 concentration in the atmosphere or changes in cosmic ray flux modulated by solar activity and geomagnetism, or possibly other factors, can at present be neglected or shown to be the overwhelming single driver of climate change in past centuries. Intensive data acquisition is required to further probe indications that the Earth's and Sun's magnetic fields may have significant bearing on climate change at certain time scales.

Cretaceous seamounts along the continent–ocean transition of the Iberian margin: U–Pb ages and Pb–Sr–Hf isotopes

To elucidate the age and origin of seamounts in the eastern North Atlantic, 54 titanite and 10 zircon fractions were dated by the U–Pb chronometer, and initial Pb, Sr, and Hf isotope ratios were measured in feldspars and zircon, respectively. Rocks analyzed are essentially trachy-andesites and trachytes dredged during the “Tore Madeira” cruise of the Atalante in 2001. The ages reveal different pulses of alkaline magmatism occurring at 104.4 ± 1.4 (2 σ) Ma and 102.8 ± 0.7 Ma on the Sponge Bob seamount, at 96.3 ± 1.0 Ma on Ashton seamount, at 92.3 ± 3.8 Ma on the Gago Coutinho seamount, at 89.3 ± 2.3 Ma and 86.5 ± 3.4 Ma on the Jo Sister volcanic complex, and at 88.3 ± 3.3 Ma, 88.2 ± 3.9, and 80.5 ± 0.9 Ma on the Tore locality. No space–time correlation is observed for alkaline volcanism in the northern section of the Tore-Madeira Rise, which occurred 20–30 m.y. after opening of the eastern North Atlantic. Initial isotope signatures are: 19.139–19.620 for 206Pb/ 204Pb, 15.544–15.828 for 207Pb/ 204Pb, 38.750–39.936 for 208Pb/ 204Pb, 0.70231–0.70340 for 87Sr/ 86Sr, and +6.9 to +12.9 for initial epsilon Hf. These signatures are different from Atlantic MORB, the Madeira Archipelago and the Azores, but they lie in the field of worldwide OIB. The Cretaceous seamounts therefore seem to be generated by melts from a OIB-type source that interact with continental lithospheric mantle lying formerly beneath Iberia and presently within the ocean–continent transition zone. Inheritance in zircon and high 207Pb of initial Pb substantiate the presence of very minor amounts of continental material in the lithospheric mantle. A long-lived thermal anomaly is the most plausible explanation for alkaline magmatism since 104 Ma and it could well be that the same anomaly is still the driving force for tertiary and quaternary alkaline magmatism in the eastern North Atlantic region. This hypothesis is agreement with the plate-tectonic position of the region since Cretaceous time, including an about 30° anti-clockwise rotation of Iberia.

P4.013 Effects of donepezil on behavioral andpsychological symptoms in Korean patients with Alzheimer's disease

We analyzed patterns of α- and β-diversity in deep-sea bivalves collected by epibenthic sleds from the western North Atlantic south of New England, and from the eastern North Atlantic in the Rockall Trough, Porcupine Seabight and Porcupine Abyssal Plain. In the western North Atlantic, species diversity, measured as the normalized expected number of species, shows a unimodal bathymetric trend peaking at mid-bathyal depths. In the eastern North Atlantic, diversity increases monotonically with depth reaching a maximum at abyssal depths. We used Baselga's (2010) metrics to distinguish two separate components of β-diversity along depth gradients, species dissimilarity among sites due to spatial replacement (turnover) and species loss leading to nestedness. We also examined the rank order of nestedness with depth using Rodríguez-Gironés and Santamaría's (2006) BINMATNEST. The primary difference in β-diversity between west and east centers on the composition of abyssal communities. In the western North Atlantic, abyssal assemblages are nested subsets of bathyal assemblages. In the eastern North Atlantic, turnover dominates at all depths. These very fundamental differences in community structure between the basins may be attributable to differences in food supply, which is greater in the eastern North Atlantic region sampled. POC-flux to abyssal depths in the east may not reach levels low enough to depress species diversity as it does in the west. In the west, the abyssal fauna is largely an impoverished nested subset of the bathyal fauna that shows less endemism and may be maintained partly by source–sink dynamics.

Tephrostratigraphy of An Loch Mór, Inis Oírr, western Ireland: implications for Holocene tephrochronology in the northeastern Atlantic region

Twelve definable cryptotephra layers younger than c. 8600cal. BP are reported from lacustrine core material taken from An Loch Mór, Inis Oírr, Aran Islands, western Ireland. The geochemistry of these shard layers, which represent more Holocene tephras than previously geochemically characterized from any European site outside the proximal volcanic influence of Italy or Iceland, is presented. Of these tephras, four may correlate with known Iceland-derived tephra horizons (Vo 1477, HI, Lairg A and H5); one appears to have two possible named correlatives (Hoy;‘Lairg B’ at Sluggan Bog, N Ireland); another has a plausible correlative (AD 860A); but two others represent Icelandic tephras apparently not previously reported on Iceland itself, including a tephra that has geochemistry very similar to Hl (AD 1104) but which dates to c. cal. AD 840. Four tephras that date from the period c. AD 40-1400 have a distinct geochemical signature that relates to Jan Mayen, 750km to the northeast of Iceland and some 1800km distant from An Loch Mór. The results contribute substantially to the chronology of the sediments from An Loch Mór and, at the international level, to the tephrostratigraphy of the northeast Atlantic region. The well-attested Icelandic H4 tephra (from a Hekla eruption of c. 4260cal. BP) was not recorded; it is suggested that An Loch Mór lies south of its recordable distribution in this part of the northeast Atlantic region. Taken together with work at other sites, the findings point to a wealth of potential tephra isochrons in Holocene deposits of the northeast Atlantic seaboard. It is clear also that calcareous lake sediments can be as fruitful a source of tephras as peats. Potential problems relating to dating and geochemical fingerprinting of tephra layers in individual sites are highlighted with reference to the Lairg tephras as recorded in Scotland and Northern Ireland, and to the Hoy tephra that has been described from Orkney.

Chapter 3

Previous hypotheses for the origin and diversification of pinnipeds have followed a narrative approach based mostly on dispersalist (i.e., center of origin) explanations. Using an analytical approach, we present a testable hypothesis to explain the evolutionary biogeography of pinnipedimorphs (fur seals, sea lions, walruses, seals, and their fossil relatives) based on both dispersal and vicariant events in the context of a species-level phylogenetic framework. This integrated hypothesis considers many lines of evidence, including physical and ecologic factors controlling modern pinniped distributions, past geologic events related to opening and closing of seaways, paleoceanographic models, the improving pinniped fossil record, and pinniped phylogenetic analyses based on both morphologic and molecular data sets. Oceanic biogeographic regions and faunal provinces are defined and oceanic circulation patterns discussed with reference to the distribution of extant and fossil species. Paleobiogeographic hypotheses for each of the major pinniped lineages are presented using area cladograms and paleogeographic maps showing oceanographic and tectonic changes during successive intervals of the Cenozoic.Our biogeographic hypothesis supports an eastern North Pacific origin for pinnipedimorphs during the late Oligocene coincident with initiation of glaciation in Antarctica. During the early Miocene, pinnipedimorphs remained restricted to the eastern North Pacific, where they began to diversify. Otariids (fur seals and sea lions) are first known from the late Miocene in the North Pacific, where they remained restricted until the late Pliocene. A transequatorial dispersal into the western South Pacific at this time preceded the rapid diversification of this group that occurred during the Pleistocene in the Southern Ocean. Odobenids (walruses) evolved in the North Pacific during the late early Miocene and underwent dramatic diversification in the late Miocene with later members of the odobenine lineage dispersing into the North Atlantic, most likely via an Arctic route. Extinct archaic phocoids, the desmatophocids, known only from the early to late Miocene, were confined to the eastern and western North Pacific. Phocids, although postulated here to have a North Pacific origin, are first known as fossils from the middle Miocene in the eastern and western North Atlantic region, as well as the Paratethys. Both monachine and phocine seals are distinct lineages beginning in the middle Miocene in the eastern and western provinces of the North Atlantic. During the late Miocene, phocids underwent a dramatic diversification. The early biogeographic history of phocine seals is centered in the Arctic and North Atlantic. Subsequent dispersal of phocines into the Paratethys and Pacific occurred during the Pleistocene. In contrast, monachine seals have a southern hemisphere center of diversity, especially the lobodontines of the Southern Ocean. Southern dispersal of this clade most likely occurred through the Neogene Central American Seaway prior to its closure in the mid-Pliocene. The pagophilic nature of extant phocine and lobodontine seals is largely a function of Pleistocene glacioeustatic events.

Semivolatile organochlorine compounds in the free troposphere of the Northeastern Atlantic.

Polychlorobiphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes, and DOTs were analyzed over 1 entire year period in the air of a high altitude remote site (2367 m above sea level) located in Teide (Tenerife, Canary Islands, 28 degrees N16 degrees W) in the Eastern North Atlantic region. Twenty samples were collected providing information on the concentrations of these semivolatile organochlorine compounds (SOCs) in the free troposphere since the stable and persistenttemperature inversion in the subtropics defines a clear separation from the marine boundary layer. More than 80% of total SOCs were in the gas phase. HCB was the individual SOC in higher concentration, 51 pg m(-3), well above than the other SOCs identified, 1-11 pg m(-3). Sum PCB concentrations were 78 pg m(-3). These concentrations range among the lowest described in atmospheric samples. The collected air originated from four main sectors, high and middle latitudes in the north Atlantic, Europe, and Africa, as determined from isentropic backward air mass trajectories. No significant differences were observed for the concentrations of these compounds between air masses showing a high uniform SOC composition of the free troposphere. Only the more volatile PCB congeners, #18 and #28, exhibited significant differences between air masses from northern and southern latitudes. A seasonal temperature dependence for the less volatile PCB congeners, five or more chlorine subtituents, was also observed. Free tropospheric concentrations of all SOCs except HCB were lower than those measured near sea level for reference. PCB concentrations at the two altitudes exhibited consistent differences according to degree of chlorination. The stronger decrease of the more volatile compounds with altitude might reflect higher photodegradation.

Identification of highest magnitude coastal storm events over western Ireland on the basis of wind speed and duration thresholds

AbstractThis paper presents a computer‐based method for the analysis of the wind record from coastal weather stations to identify storm events based on wind speed and duration thresholds. Various combinations of thresholds help identify two main storm signatures, i.e. peak‐like and plateau‐like profiles. Seven further types of storm are defined according to their intensity. The date of each event provided by the program is a key item in the analysis that allows for the establishment of storm catalogues at individual weather stations. Catalogues that identify particular storms produce information on the varying local storm regime of the western Irish seaboard and provide input to the understanding of the climatology of the wider northeastern Atlantic region. Copyright © 2001 Royal Meteorological Society

Reconstruction of monthly 700, 500 and 300 hPa geopotential height fields in the European and Eastern North Atlantic region for the period 1901-1947

Gridded geopotential height (gph) fields at 700, 500 and 300 hPa were reconstructed back to 1901 based on sea level pressure, temperature and precipitation data over the European and Eastern North Atlantic region using canonical correlation analysis. Sensitivity analysis showed that the cumulative shared variance of the prefiltered (by means of principal component analysis) gph fields should be on the order of 95 to 99%, and for the predictors lower than 90%, in order to achieve reliable reconstructions. The obtained relations between the surface data and the gph fields were robust and the promising cross-validation results were revealed to be reproducible in a second inde- pendent period. The main mode of wintertime 700, 500 and 300 hPa gph field variability in the 20th century is a dipole pattern that clearly shows the signature of a regional representation of the Arctic Oscillation (AO). The time series of this mode of variability implied a strengthening of the gph gradi- ents in the troposhere over Europe in the last decades of the 20th century; this is without precedent in the 20th century.

ON THE OCCURRENCE OF THE CHINESE MITTEN CRAB, ERIOCHEIR SINENSIS, IN PORTUGAL (DECAPODA, BRACHYURA)

ON THE OCCURRENCE OF THE CHINESE MITTEN CRAB, ERIOCHEIR SINENSIS , IN PORTUGAL (DECAPODA, BRACHYURA) BY H. N. CABRAL and M. J. COSTA Instituto de OceanograŽ a, Faculdade de Ci ˆ encias de Lisboa, Campo Grande, P-1700 Lisboa, Portugal ABSTRACT The present paper reports the occurrence of the Chinese mitten crab, Eriocheir sinensis H. Milne Edwards, 1854, in Portugal and thus extends its known southerly distribution for Europe. Avail- able Portuguese data are presented and discussed including a possible new size record for the northeastern Atlantic region. R ´ ESUM ´ E La pr ´ esence du Crabe Chinois, Eriocheir

Water masses and their circulation off western Iberia during May 1993

The distribution of the water masses and their circulation in the eastern North Atlantic region off the northern half of the west coast of the Iberian Peninsula are analysed here based on CTD measurements made in May 1993 during the “MORENA 1” cruise. The upper layers of the ocean, down to about 100m, showed a typical spring, non-upwelling situation with a very shallow seasonal thermocline overlying thicker remnants of the mixed layer from the previous winter. Below, Central Water extended between a subsurface salinity maximum near depths of 100–140m and a salinity minimum at about 500m. Using quantitative water mass analysis and geostrophic calculations, a poleward surface current reaching down to depths of 250m and transporting relatively warm and saline Eastern North Atlantic Central Water (ENACW) of subtropical origin was characterised, centred at a few tens of km offshore the shelf break, therefore indicating that the northward current identified previously in this region during winter (the Portugal Coastal Countercurrent) continues to be present through the spring season. A large-scale transition zone, the Galicia Front, was found in the northwest area of the study region, reaching from the surface layers down to the depths of the Mediterranean Water. To the north of this front, relatively fresh Central Water of Western Atlantic origin replaced the subtropical branch of ENACW. At the deeper Central Water levels, ENACW from subpolar North Atlantic origin was present through the whole study region. The influence of the upper and lower cores of Mediterranean Water was present, centred at levels of 800 and 1100m, as indicated by their characteristic thermohaline maxima. The deduced flow of Mediterranean Water was towards the north in the whole study region, in clear relation with the Portugal Slope Undercurrent, and showed some tendency to branch towards the west through the gap between the Vigo Seamount and the Galicia Bank. The Mediterranean upper core occupied a relatively thin layer, O (100m), and underwent a strong dilution of about 45% from the south to the north of the study region; the lower core spread over a larger depth range, of about 400–500m, and decayed only by about 20% through the region. Below the Mediterranean Water, the influence of North Atlantic Deep Water spread through the study region, and an intermediate layer of Labrador Sea Water was also present, particularly offshore in the northwest zone.

A conversation with William M. Haenszel

William M. Haenszel was born on June 19, 1910, in Rochester, New York. He received a B.A. degree in 1931 and an M.A. degree in 1932, both from the University of Buffalo. He is an elected Fellow of the American Statistical Association, the American Public Health Association and the American Association For the Advancement of Science. He has been awarded a Doctor Honoris Causa en Salud Publica from the Universidad del Valle in Colombia. He has held positions as Secretary of the Statistics Section and member of the governing Council of the American Public Health Association, Chair of the Biometrics Section of the American Statistical Association and member of the Regional Advisory Board of the Eastern North Atlantic Region of the International Biometric Society. During his tenure at the National Institutes of Health (NIH) from 1952 through 1976, he served as Head of the Biometric Section and the Chief of the Biometry Branch at the National Cancer Institute. Since leaving the National Institutes of Health he was on staff at the Illinois Cancer Council, Professor of Epidemiology at the University of Illinois (he is currently Professor Emeritus) and a consultant to the World Health Organization.

Early Eocene palaeoceanography and palaeoclimatology of the eastern North Atlantic: stable isotope results for DSDP Hole 550

Abstract High-resolution oxygen and carbon isotope records for benthonic and planktonic foraminifera have been established through the early Eocene at DSDP Site 550, Goban Spur in the North Atlantic. Benthonic stable isotopic records from Site 550 (estimated palaeodepth c. 4000 m) represent the first documentation of actual deep water properties during the early Eocene. At Site 550 in the earliest Eocene (end of NP10 Zone), a 0.5‰ vertical δ 18 O (i.e. thermal) gradient between subsurface and bottom water was eliminated, probably reflecting upward displacement of subsurface water by intermediate and deep water. Thereafter vertical isothermal conditions prevailed for the rest of the early Eocene. This is consistent with earlier findings suggesting unusually low vertical and latitudinal temperature gradients in the early Eocene ocean. A comparison of the isotopic records from Site 550 and nearby DSDP Site 401 (palaeodepth 1800 m), reflecting intermediate water properties, confirms the isothermal nature of the water column in the eastern North Atlantic. This is in contrast to earlier findings for the Antarctic region (ODP Sites 689 and 690) in the early Eocene, where supposedly warm bottom waters originating in low latitudes were overlain by cooler intermediate waters originating in high latitudes. Both the oxygen and the carbon isotopic records for Sites 550 and 401 indicate that the eastern North Atlantic region was influenced by a single source of intermediate-to-deep water through most of the early Eocene. The benthonic δ 18 O and δ 13 C values for Site 550 are generally low compared with coeval sections worldwide, indicating that during most of the early Eocene the North Atlantic was dominated by warm and nutrient-enriched deep water formed in a low latitude region. The earliest stages of the long-term cooling trend, which characterizes the second part of the Paleogene, can be traced by a 2°C decrease in bottom water temperatures across the NP13–NP14 transition at both Sites 550 and 401.