Reproduction,hatching success,and early naupliar survival in Centropages typicus

The broadcast spawner, Centropages typicus, is a very successful copepod species in many coastal areas of the Mediterranean Sea and North Atlantic Ocean. This review assembles the large amount of information on the reproduction and early life history of C. typicus that has emerged since the 1970s and has made this species one of the best-studied copepods, similar in that regard to species of Acartia and Calanus. Observations on mating behavior and the female gametogenic and oogenic cycles are presented, together with information on seasonal cycles of egg production rates in Mediterranean and Atlantic populations from various regions. These studies indicate a strong latitudinal gradient, with continuous reproduction and the main spawning season occurring earlier (late winter/spring) in warmer waters such as the Mediterranean Sea, compared to northern areas such as the North Sea and in the Kattegat, where C. typicus actively reproduces mainly in late summer and fall with reproduction ceasing altogether in winter in the German Bight. These observations strongly suggest that temperature is the controlling factor for reproductive activity in this species. Egg development times are also temperature dependent but do not vary with latitude, and there is as yet no conclusive evidence that diapause egg production occurs in C. typicus. Laboratory experiments have shown that food quantity and quality both affect fecundity and offspring fitness, but most of these studies have focused on diatom and dinoflagellate diets and non-algal prey have been strongly underrepresented, despite their importance for this omnivorous copepod. Large fluctuations in hatching success and naupliar survival have been reported in field surveys and have subsequently been related to maternal feeding history and food quality or toxicity in laboratory experiments. We identify future lines of research that will help to explain the interannual variability in breeding intensity and recruitment of C. typicus in the field based on better understanding of the species’ reproductive biology.     

First record of a Vestimentifera (Polychaeta: Siboglinidae) from chemosynthetic habitats in the western Mediterranean Sea—Biogeographical implications and future exploration

A new population of vestimentiferan tubeworms was discovered during a recent expedition to a mud volcano field in the Alboran Sea, western Mediterranean Sea. Morphological data and mitochondrial cytochrome-c-oxidase subunit 1 (COI) sequences show that the Alboran tubeworm is essentially identical to Lamellibrachia sp. found in the eastern Mediterranean. This is the first record of a vestimentiferan species in the western basin of the Mediterranean, an area with direct connection to the Atlantic via the Strait of Gibraltar and therefore of great importance to the study of distributional patterns and evolution of Mediterranean species. We examine the current hypotheses on the biogeographic distribution of vestimentiferan species in the eastern Atlantic and Mediterranean Sea and conclude that independently of when Lamellibrachia colonized the Mediterranean, neither the present hydrological settings of both Mediterranean Sea and Atlantic Ocean, nor vestimentiferans reproductive biology are impeditive to the presence of the Mediterranean species of Lamellibrachia in the NE Atlantic. The West African and Lusitanian margins are the most likely places to find living populations of this species in the NE Atlantic.     

Submarine ridges do not prevent large-scale dispersal of abyssal fauna: A case study of Mesocletodes (Crustacea, Copepoda, Harpacticoida)

We examined the large-scale distribution of deep-sea harpacticoid copepods at the species level, in order to clarify the underlying processes of copepod dispersal. The study was based on samples collected from 12 regions and a total of 113 stations: 57 stations at depths between 1107 and 5655 m on abyssal plains in the South and North Atlantic, Southern Ocean, southern Indian Ocean, and the Pacific Ocean, and 56 stations above 900 m in the North Atlantic and eastern Mediterranean Sea.We chose the genus Mesocletodes Sars, 1909 as an ideal group to study the large-scale distribution of harpacticoid copepods in the deep oceans. Clear apomorphies and a comparatively large body size of about 1 mm allow rapid recognition of allied species in meiofauna samples. In addition, Mesocletodes represents more than 50% of the family Argestidae Por, 1986, one of the most abundant harpacticoid families in the deep sea.The geographical distributions of 793 adult females of Mesocletodes belonging to 61 species throughout the South and North Atlantic, Southern Ocean, southern Indian Ocean, Pacific Ocean, and eastern Mediterranean Sea indicated that most species are cosmopolitan. Neither the topography of the sea bottom nor long distances seem to prevent species from dispersing. Passive transport by bottom currents after resuspension is likely the propulsive factor for the dispersal of Harpacticoida, while plate tectonics and movement of individuals in the sediment may play relatively minor roles.     

Temporal variability of Centropages typicus in the Mediterranean Sea over seasonal-to-decadal scales

Centropages typicus is one of the most common, abundant and best studied calanoid copepods in neritic waters of the Mediterranean Sea, which means it can provide useful information about the long-term dynamics of the Mediterranean epipelagic ecosystem. This paper presents the first comparative overview of the seasonal and long-term variability of C. typicus in different Mediterranean regions. This review is based on quantitative information from the published literature and novel data from five ongoing zooplankton time-series carried out in the Mallorca Island (Balearic Sea), the Bay of Villefranche (Ligurian Sea), the Gulf of Naples (Tyrrhenian Sea), the Gulf of Trieste (North Adriatic Sea), and the Saronikos Gulf (Aegean Sea). In most Mediterranean regions, C. typicus has a perennial occurrence, with peaks of abundance that reflect the succession of different generations. Throughout the Mediterranean, the annual cycle of C. typicus is characterized by minima in winter and major peaks in April–June, which is earlier than those observed in European Atlantic waters, where the peaks are more frequently recorded in summer and fall. In the regions investigated, the annual cycle shows remarkable similarities in terms of timing, but notable differences in the peak height; populations are far more abundant in coastal north-western regions and less abundant in the eastern basin. In the long-term, changes in C. typicus phenology observed in the Bay of Villefranche and in the Gulf of Naples are related to the North Atlantic Oscillation (NAO) index. In these two regions, the species responds to climate forcing similarly in terms of average seasonal patterns (bi-modal patterns in years of positive NAO, unimodal patterns in years of negative NAO) but oppositely in terms of quantity, indicating different influence of the NAO on the two regions. At decadal scales, C. typicus populations show high interannual variability with marked geographical differences. In some areas, the patterns are clearly characterized by alternate phases of higher and lower annual abundances, at higher frequency (mainly 1–2 years) in the Gulf of Naples, and lower frequency in the Saronikos Gulf (mainly 4–5 years) and in the Gulf of Trieste (mainly 5–6 years). Synchronous phases of increasing or decreasing abundance are discernable only for a few sites and short periods, for example from 1998 to 2000 in the Gulf of Naples, Gulf of Trieste and Saronikos Gulf. The regional differences observed in the long-term patterns of C. typicus populations suggest that the temporal dynamics of this species are significantly more affected by local conditions than by any possible common driving force acting at basin scale through teleconnections.     

2003年夏季西北冰洋浮游动物群落结构和地理分布研究

根据西北冰洋43个调查站位的浮游动物种类组成和数量资料,分析了浮游动物的群落结构和地理分布特征,探讨了浮游动物群落与环境因子的关系.结果表明,在调查区域存在三种不同的浮游动物群落类型:楚科奇海台和加拿大海盆地区的高纬度深海群落;楚科奇海中部的陆架群落;阿拉斯加沿岸和楚科奇海北部的沿岸过渡群落.深海群落浮游动物数量较少,...     

Hydrodynamic,non-photic modulation of biorhythms in the Norway lobster,Nephrops norvegicus (L.)

Data on biological rhythms of the Norway lobster Nephrops norvegicus (L.) are compared with new findings on inertial currents, a non-photic geophysical hydrodynamic fluctuation. Laboratory experiments on animal endogenous cardiac activity and locomotor rhythms using individuals from the middle slope (400–600 m depth) of the Mediterranean Sea revealed a consistent proportion of ultradian 18-h animals (20.6% and 12.0% of the studied cases for cardiac and locomotor tests, respectively). This characteristic, not reported in similar experiments with individuals from shallower depths (20–200 m) in the Atlantic Ocean, was initially considered meaningless from an ecological point of view. However, a close comparison with in situ oceanographic measurements over 1 year revealed a clear relationship between inertial current fluctuations and the observed 18-h behavioural and physiological rhythms. We propose a novel scenario involving potential non-photic (i.e. hydrodynamic) modulation of Nephrops biorhythms, and suggest that this may provide a paradigm for other benthic species in deep-water areas.     

First in situ observations of the deep-sea carnivorous ascidian Dicopia antirrhinum Monniot C., 1972 in the Western Mediterranean Sea

Dicopia antirrhinum C. Monniot, 1972 is a rare species of deep-sea ascidian belonging to the Family Octacnemidae, reported at depths of 1000–2500 m in European Atlantic waters. Adult individuals have never been reported before in the Mediterranean Sea, where only seven juvenile specimens were found in 1975 at 500 m water depth in the Central basin (Malta). The affinities of these specimens with D. antirrhinum were noted, but lack of some typical characters of the species in juveniles prevented a definite taxonomical identification. No other member of the Octacnemidae has ever been found in the Mediterranean. In this study we describe the sampling of an adult specimen of D. antirrhinum at around 1100 m water depth on the flank of the La Fonera (Palamós) canyon, Northwestern Mediterranean, confirming their presence in the Mediterranean Sea. We also observed 5 individuals of this species on their natural habitat with a Remotely Operated Vehicle (ROV). Our results highlight the potential occurrence of Octacnemidae, the presence of which has been largely overlooked, in several deep-sea canyon areas within the Western Mediterranean basin. These observations are important because they indicate the need for increased sampling effort with new technologies, such as ROVs, in ecologically relevant habitats such as canyons, in order to obtain a more accurate picture of deep-sea biodiversity in the Mediterranean Sea.     

Biomass of zooplankton in the eastern Arctic Ocean – A base line study

Only a few historical assessments of the zooplankton biomass in the Arctic Ocean exist are difficult to compare due to methodological differences including incomplete sampling of the water column. We present assessments of the zooplankton biomass for 66 locations scattered over the Eurasian and Makarov Basins of the Arctic Ocean and analyze regional variability and factors affecting the biomass distribution. The study is based on material from several summer expeditions of RV Polarstern (1993–1998) that was collected and processed using consistent methods, i.e. stratified sampling of the entire water column from the bottom to the surface with very similar gear and standardized calculation of biomass. Total zooplankton biomass varied strongly from 1.9 to 23.9 g DW m⁻² dry mass. Regional variability was mainly related to the circulation pattern, but local food availability was also important. A belt of elevated biomass along the Eurasian continental margin was associated with the advection of Atlantic pelagic populations within the Arctic Ocean Boundary Current along the Siberian shelves and returning branches along mid-ocean ridges. Biomass was highest in the core of the Atlantic inflow and remained rather stable along the continental margins, but species composition changed, pointing to different adaptation levels to local conditions by advected species. Biomass gradually decreased towards the shelves and basins and was lowest in the centers of the basins north of 85°N. In the slope region, three Calanus species (C. hyperboreus, C. glacialis, C. finmarchicus) and Metridia longa contributed most to the biomass, chaetognaths (Eukrohnia hamata) were also important. In the basins, C. hyperboreus was dominant, copepods made up to 97% of total biomass. Vertical distribution was similar at all stations with biomass maxima in the upper 50 m layer except for stations near Fram Strait and northern Kara Sea, the gateways of Atlantic water to the Arctic Ocean, where maxima where between 25 and 100 m. As there was only very little interannual variability of temperature and current velocity in the regions of the Atlantic inflow we suggest that the majority of our samples, collected in 1993 and 1995, represents the phase of the 1990s warm event in the Nordic Seas.     

Zooplankton distribution across the Lomonosov Ridge,Arctic Ocean: species inventory,biomass and vertical structure

On a transect across the Lomonosov Ridge stratified zooplankton tows were made to the bottom at seven stations. A species inventory was established and compared with earlier observations in the Arctic Ocean. Differences between the Amundsen and Makarov basins are relatively small and correspond well with the general circulation patterns for Atlantic, Pacific, and neritic waters, suggesting slow mixing rates for the different basins. There were no remarkable differences in the species composition or their vertical distribution between the two sides of the Lomonosov Ridge. This indicates effective faunistic exchange across the ridge, although several bathy-pelagic species were almost or completely absent on top of the Ridge. Biomass showed a strong gradient along the transect, with a pronounced peak (9.5 g dry weight m⁻²) in the core of Atlantic water over the ridge, and minima over the deep basins. These differences were related to the effect of bottom topography for deep-living species, and the dynamics of the Atlantic layer for the meso- and epipelagic species. The maximum was formed mainly by the copepods Calanus hyperboreus and Metridia longa together with chaetognaths and ostracods. The presence of young developmental stages in some of the abundant species (C. hyperboreus, M. longa) suggests successful reproduction at all stations but C. finmarchicus was almost exclusively represented as old stages and adults. Comparison with earlier data on abundance and biomass from the Canada Basin (Russian Drift station “North Pole-22”) shows a pronounced difference with respect to both absolute quantities and relative composition. The copepod C. finmarchicus is completely absent in the central Canada Basin, and the portion of non-copepod zooplankton is dramatically decreased. This points to a reduced advection of Atlantic water or more severe food conditions in this basin.     

Distribution of Calanus finmarchicus in the northern North Atlantic and Arctic Ocean—Expatriation and potential colonization

The distribution of Calanus finmarchicus was studied on a transect across the central Greenland Sea, and on five transects from the Eurasian shelves across the Atlantic Inflow in the Arctic Ocean. Stage composition was used as an indicator for successful growth; gonad maturity and egg production were taken as indicators for reproductive activity. On the Arctic Ocean transects, these parameters were measured simultaneously from the sibling species Calanus glacialis. Response of egg production rate to different temperatures at optimal food conditions was very similar between both species in the laboratory. C. finmarchicus was present at all stations studied, but young developmental stages were only present close to the regions of submergence of Atlantic water under the Polar water. This together with a decreasing abundance and biomass from west to east along the Atlantic Inflow in the Arctic Ocean and reproductive failure indicates that C. finmarchicus is expatriated in the Arctic Ocean. We hypothesize that the late availability of food in the Arctic Ocean, rather than low temperature per se, limits reproductive success. Better reproductive success in the very low temperature regions of the Return Atlantic Current and the marginal ice zone in the Greenland Sea supports this hypothesis. The possibility for a replacement of C. glacialis by C. finmarchicus and consequences for the ecosystem after increasing warming of the Arctic are discussed.     

A pilot study of genetic differentiation between two phenotypes of a Mediterranean population of the bivalve Cerastoderma glaucum and genetic discrimination with other Cerastoderma glaucum and Cerastoderma edule populations outside the Mediterranean

The internal transcribed spacer 1 (ITS1) region of 29 individuals of Cerastoderma glaucum (from the Mediterranean Sea, the Atlantic and the North Sea) and 18 individuals of Cerastoderma edule (from the Atlantic and the North Sea) and the cytochrome c oxidase subunit I (COI) region of 43 individuals of C. glaucum (from the Mediterranean Sea, the Atlantic and the North Sea) and 9 individuals of C. edule (from the Atlantic and the North Sea) were PCR amplified and sequenced. The ITS1 sequences led us to describe 27 genetic haplotypes, while 21 genetic haplotypes were determined via the COI sequences. The ITS1 and the COI sequences revealed an important genetic variability within the Mediterranean population of C. glaucum, which contained two different phenotypes: orange foot and yellow foot. A genetic differentiation between the two phenotypes was revealed by the nucleotide diversity index (π) and is strengthened by the AMOVA analysis. This result leads us to suspect the presence of two different groups in the same population of C. glaucum. Nevertheless to be confirmed this hypothesis requires further studies using more locations and a larger number of sample sizes.     

The biology and ecology of Centropages typicus: An introduction

We briefly introduce the different chapters of this special issue which review the current knowledge and understanding of the biology and ecology of Centropages typicus obtained over the last 30 years. The papers are grouped into two major theme areas: the first five papers review behaviour, feeding, metabolism, growth and development, and reproduction, and the four following papers have a regional focus dealing with temporal and spatial distribution in the Mediterranean Sea and in the North Atlantic shelf areas. The findings reviewed in the two groups of papers converge to explain why C. typicus is such a very successful copepod species in these coastal areas. In the different chapters, similarities and differences with congeneric species (C. velificatus, C. hamatus, C. brachiatus, C. chierchiae, C. furcatus, and C. abdominalis) have been explored where these are known.     

Macroecological study of Centropages typicus in the North Atlantic Ocean

Centropages typicus is a temperate neritic-coastal species of the North Atlantic Oceans, generally found between the latitudes of the Mediterranean and the Norwegian Sea. Therefore, the species experiences a large number of environments and adjusts its life cycle in response to changes in key abiotic parameters such as temperature. Using data from the Continuous Plankton Recorder (CPR) survey, we review the macroecology of C. typicus and factors that influence its spatial distribution, phenology and year-to-year to decadal variability. The ecological preferences are identified and quantified. Mechanisms that allow the species to occur in such different environments are discussed and hypotheses are proposed as to how the species adapts to its environment. We show that temperature and both quantity and quality of phytoplankton are important factors explaining the space and time variability of C. typicus. These results show that C. typicus will not respond only to temperature increase in the region but also to changes in phytoplankton abundance, structure and composition and timing of occurrence. Methods such as a decision tree can help to forecast expected changes in the distribution of this species with hydro-climatic forcing.     

The occurrence of pathogenic bacteria in some ships' ballast water incoming from various marine regions to the Sea of Marmara,Turkey

The composition and frequency of antibiotic resistance of pathogenic bacteria, the abundance of heterotrophic aerobic bacteria (HPC) and possible in-situ use of chromogenic agar were investigated in the ships' ballast water coming from different regions of the world to the Sea of Marmara, Turkey for the first time. The samples that were taken from 21 unit ships coming from various marine environments of the Southern China Sea, the Atlantic Ocean, the Mediterranean and the Black Sea to the Sea of Marmara, Turkey in 2009 and 2010 were tested. 38 bacteria species, 27 of them pathogenic bacteria belonging to 17 familia, were detected. Vibrio cholera was not detected in the samples. However, the presence of a high number of HPC, including a cocktail of pathogenic bacteria showed that the ships carry a potential risk for the Sea of Marmara.     

Sources and distribution of fresh water in the East Greenland Current

Fresh water flowing from the Arctic Ocean via the East Greenland Current influences deep water formation in the Nordic Seas as well as the salinity of the surface and deep waters flowing from there. This fresh water has three sources: Pacific water (relatively fresh cf. Atlantic water), river runoff, and sea ice meltwater. To determine the relative amounts of the three sources of fresh water, in May 2002 we collected water samples across the East Greenland Current in sections from 81.5°N to the Irminger Sea south of Denmark Strait. We used nitrate-phosphate relationships to distinguish Pacific waters from Atlantic waters, salinity to obtain the sum of sea ice melt water and river runoff water, and total alkalinity to distinguish the latter. River runoff contributed the largest part of the total fresh water component, in some regions with some inventories exceeding 12 m. Pacific fresh water (Pacific source water S ∼ 32 cf. Atlantic source water S ∼ 34.9) typically provided about 1/3 of the river runoff contribution. Sea ice meltwater was very nearly non-existent in the surface waters of all sections, likely at least in part as a result of the samples being collected before the onset of the melt season. The fresh water from the Arctic Ocean was strongly confined to near the Greenland coast. We thus conjecture that the main source of fresh water from the Arctic Ocean most strongly impacting deep convection in the Nordic Seas would be sea ice as opposed to fresh water in the liquid phase, i.e., river runoff, Pacific fresh water, and sea ice meltwater.     

Spatial variability in the trophic ecology and biology of the deep-sea shrimp Aristaeomorpha foliacea in the Mediterranean Sea

The trophic ecology, energy and reproductive states of the deep-water shrimp Aristaeomorpha foliacea, widely distributed along the slopes of the Mediterranean Sea Basins, were analysed in eight areas spread along ca. 3000 km in order to identify patterns in the habitat conditions supporting the species. From W to E the areas were situated between the north side of Eivissa (39°12′N, 1°20′E, in the Balearic Basin) and off Mersin, Turkey (36°15′N, 34°19′E, in the Levantine Sea). Trends identified mainly as a function of longitude from west to east were: (i) higher δ¹⁵N, parallel to δ¹⁵N shifts in the top 200 m of the water column for particulate organic N (Pantoja et al., 2002). The δ¹⁵N trend indicates that the deep trophic web, i.e. A. foliacea at 400–600 m, reflects the δ¹⁵N signal of the photic zone; (ii) a similar significant trend of δ¹³C, related with exploitation of pelagic versus benthic resources by A. foliacea in each area (i.e. by local variability of terrigenous inputs via submarine canyons). More depleted δ¹³C was found at mid-longitudes (Tyrrhenian Sea and Sicily Channel) linked to higher consumption of macroplankton prey (Pasiphaea spp., euphausiids and mesopelagic fishes). The feeding intensity (gut fullness, F) and prey diversity (J) of A. foliacea were related, according to generalized linear models, with the temperature and salinity of intermediate waters, variables in turn associated with latitude and longitude. Both F and J were higher in areas with greater shrimp density. The optimal ecological habitat of A. foliacea appears to be located in the Tyrrhenian Sea and the Sicily Channel, where we found the highest F, the greatest trophic diversity and A. foliacea in the best biological condition (i.e. with higher hepato-somatic index, HSI). These are also the areas with the highest densities of A. foliacea. In contrast, in the western Mediterranean Sea (Balearic Basin and the southern Balearic Islands), where A. foliacea has low densities, the shrimp showed generally lower values of trophic indicators and biological condition.     

The hydrography of the mid-latitude Northeast Atlantic Ocean: II: The intermediate water masses

The intermediate water masses in the eastern Atlantic Ocean between 31°N and 53°N were studied by analysis of the distributions of potential temperature, salinity, dissolved nutrients and oxygen. Sub-surface salinity minima are encountered everywhere in the area. At the northern and southern boundary they are connected with the presence of Sub-Arctic Intermediate Water and Antarctic Intermediate Water, respectively, but towards the European ocean margin the sub-surface salinity minima shift to shallower density levels. The sub-surface salinity minima observed west of the Iberian Peninsula represent a water mass formed by winter convection in the Porcupine Sea Bight and the northern Bay of Biscay. These minima gain salt by diapycnal mixing with the underlying Mediterranean Sea Outflow water and with the overlying permanent thermocline. The core of Antarctic Intermediate Water appears to contribute to the formation of Mediterranean Sea Outflow Water since it becomes entrained into the overflow near Gibraltar. This entrainment gives rise to an enhanced concentration of the nutrients in the Mediterranean water in the North Atlantic. The deep salinity minimum, due to the presence of Labrador Sea Water, is restricted mainly to the Porcupine Abyssal Plain. In the Bay of Biscay this water type is strongly modified by enhanced diapycnal mixing near the continental slope. At all intermediate levels the continental slope in the Bay of Biscay seems to be a focal point for water mass modification by diapycnal mixing. Below the core of the Mediterranean Sea Outflow Water the Labrador Sea Water is also strongly modified. Its salinity is strongly enhanced by diapycnal mixing with the overlying core of Mediterranean Sea Outflow Water. An analysis of the oxygen and nutrient data indicates that the large spatial concentration differences at the level of the Labrador Sea Water are caused mainly by ageing of the water. The youngest water is observed at 52°N, and, especially in the Bay of Biscay and off south-west Portugal, the water at levels of about 1700 dbar are strongly enriched in nutrients and depleted in oxygen.     

Nannoplankton of the Atlantic Ocean from sediment trap samples

Calcareous nannoplankton from sediment trap samples collected at six sites in the Atlantic Ocean from 23° S to 73° N (cruise 20 of R/V Vityaz’ and cruise 33 and 34 of R/V Akademik Mstislav Keldysh). Those samples were studied with a scanning electron microscope. In the coastal and open-sea regions of the North and South Atlantic and in the subarctic region of the Norwegian Sea, the conditions are significantly different. In the shelf area of the Benguela upwelling, 11 species were recognized; some of them were agglutinated by diatoms and tintinnides or covered the surface of pellets. The Broken Spur and TAG pelagic areas of the North Atlantic contained up to 43 coccolith species. They included holococcoliths, large pelagic, and delicate easily soluble species distributed over the entire water column. The presence of coccoliths in the high-latitude area of the Norwegian Sea is related to their supply with the warmer North Atlantic waters. These assemblages are distinguished by a low species diversity and an enhancement of the coccolith solubility with the depth increase.     

Eolian dust from the lower atmosphere of the eastern Atlantic and Indian Oceans,China Sea and Sea of Japan

Dust-loadings in the lower atmosphere of the Atlantic and Indian Oceans and the China Sea and Sea of Japan are given. Average dust-loadings decrease in the following order: North Atlantic (northeast trades, ～ 7.7 μg/m³ of air) > northern Indian Ocean (～ 1.2 μg/m³ of air) > South Atlantic (southeast trades, ～ 0.78 μg/m³ of air) = southern Indian Ocean (～ 0.68 μg/m³ of air) > China Sea (～ 0.21 μg/m³ of air).There are differences in the clay mineralogies of dusts transported in similar latitudes in the North Atlantic and northern Indian Oceans. Dusts in the Atlantic northeast trades are dominated by kaolinite from the soils of equatorial Africa; dusts in the northeast monsoons of the northern Indian Ocean have a source in the arid regions of the Rajasthan desert where illite is the principal clay mineral.In the regions investigated quartz occurs in larger amounts in the dusts of the Northern Hemisphere (～ 7% quartz) than those of the Southern Hemisphere (～ 3% quartz) over both the Atlantic and Indian Oceans.From the results given in the present paper and those reported in the literature a map is presented illustrating the order of magnitude of lower atmospheric dust-loadings in part of the world ocean.