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We describe four new species and a new genus of very small (< 500 µm) Foraminifera from the Challenger Deep, the deepest point in the world's oceans (10 896 m water depth). All have transparent, mainly organic test walls that incorporate some minute agglutinated mineral particles of various shapes and compositions. Nodellum aculeata sp. nov. has an elongate proloculus with a pointed proximal end followed by a long, tubular section. The genus Resigella is represented by two species: in R. laevis sp. nov., the test comprises 3–4 elongate, oval to cylindrical chambers while R. bilocularis sp. nov. has an oval proloculus followed by a second, larger globular chamber. The fourth species, Conicotheca nigrans gen. et sp. nov., is characterized by a tiny, elongate, conical test filled with dark stercomata. Except in C. nigrans, the test wall has a brownish tinge; energy-dispersive spectroscopy (EDS) suggests the presence of organically bound Fe in all species including C. nigrans. Scanning electron microscopy (SEM) combined with EDS reveals distinctive wall structures. In N. aculeata, the proloculus is strewn with tiny (< 0.7 µm), elongate grains. In this species and in R. laevis, the test surface (except for the proloculus) is covered with a carpet of minute (∼0.1 µm) finger-like projections, rather similar to the organic cement of agglutinated Foraminifera. In R. bilocularis, the larger second chamber often has a partial veneer of fine mineral grains of varying composition, as well as organic areas consisting of meshed strands. SEM images of these three species reveal flat, plate-like features that we interpret as clay particles. In C. nigrans, the wall is relatively featureless except where the surface is raised into hummocky mounds and scale-like features, again probably clay particles. We suggest that these species represent a distinctive group of ‘agglutinated’ Foraminifera in which the test is predominately organic. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153, 399–423. [ABSTRACT FROM AUTHOR]

Abstract: Atmospheric input of fixed nitrogen species to the ocean has attracted considerable attention from the viewpoint of the oceanic biogeochemical cycle of nitrogen, although few measurements of organic nitrogen compounds in atmospheric aerosols have been extensively conducted over remote ocean areas. In this study, we report the geographical distribution of dissolved free amino acids (DFAA) in the water-soluble fraction of two size-segregated marine aerosols over the western North Pacific. The concentrations of DFAA showed higher values over the region north of 30°N, whereas they clearly decreased south of 30°N. Approximately 59–96% of DFAA was found in fine-mode particles. Long-range transport from continental sources could largely contribute to DFAA in marine aerosols over the remote North Pacific. [Copyright &y& Elsevier]

Abstract: We collected sea fog (stratus), cloud forming a continuous horizontal gray sheet, over the northern North Pacific and its marginal seas (Sea of Japan, Sea of Okhotsk, and Bering Sea) in late spring through summer from 1998 to 2001. Non-sea-salt component occupies maximum 54% of ion in fog water, and hence sea fog waters are usually acidified over a wide region of the seas which is far from the anthropogenic emission sources on land. Both nss-SO42- and H+ mainly contribute to the non-sea-salt fraction. The ratios of MSA/Na+ in rain waters range from 0.00051 to 0.0046. In contrast, the regional mean ratios in fog water range from 0.0042 to 0.16. Sea fog scavenges MSA aerosol produced from the oxidation of DMS more effectively than rain. We characterize the typical chemical composition of sea fog, and find that each region has specific character in the relationship between acidifying potential (AP=[nss-SO42-]+[NO3-]) and neutralizing potential (NP=[NH4+]+[nss-Ca2+]), which relationship leads to the illumination for the acidification process. [Copyright &y& Elsevier]

Atmospheric concentrations of non-sea-salt sulfate (nss-SO 4 2− ) and methanesulfonic acid (MSA) were measured over the Pacific Ocean between 48°N and 55°S during the KH-08-2 and MR08-06 cruises in summers of 2008 and 2009, in order to investigate spatial distributions of each species and MSA/nss-SO 4 2− ratio. In the subarctic western North Pacific, mean concentrations of nss-SO 4 2− and MSA in bulk (fine + coarse) aerosols were 1.1 μg m −3 and 0.061 μg m −3 , whereas those in the South Pacific were 0.25 μg m −3 and 0.043 μg m −3 , respectively. In the subtropical western North Pacific, it was observed that nss-SO 4 2− concentration sharply increased from 0.45 μg m −3 up to 4.2 μg m −3 under the dominant influence of the Kilauea volcano, while that of MSA remained low. Mean MSA/nss-SO 4 2− ratio observed in the South Pacific was approximately 3.7 times higher than that in the subarctic western North Pacific, although the mean MSA concentration in the subarctic western North Pacific was a factor of 1.4 higher than that in the South Pacific. The distributions of nss-SO 4 2− , MSA, and MSA/nss-SO 4 2− ratio suggested that aerosol nss-SO 4 2− plays a key role in the latitudinal variation in MSA/nss-SO 4 2− ratio over the North and South Pacific during summer periods, and that high MSA concentrations in the subarctic western North Pacific and the South Pacific were related to high biological productivity and low air temperature. During the cruises, an inverse relationship ( r = −0.72, p < 0.01) was observed between satellite-derived chlorophyll a concentration and air temperature, showing that high biological productivity occurred at high latitudes, where air temperature were relatively low, in both hemispheres during the summer periods. Although both MSA concentration and MSA/nss-SO 4 2− ratio showed inverse and positive relationships with air temperature and chlorophyll a concentration, respectively, the correlations between these variables were weak, suggesting that the distributions of MSA concentration and MSA/nss-SO 4 2− ratio over the North and South Pacific during the summer periods were influenced by more complex factors. Estimates using the MSA/nss-SO 4 2− ratios measured in different latitude regions in the Pacific Ocean indicated that the contributions from biogenic sources accounted for 9.6–58% of the total nss-SO 4 2− in aerosols collected in the subarctic western North Pacific, 15–85% in the subtropical western North Pacific, 10–70% in the central North Pacific, and 12–97% in the South Pacific, showing strong influence of anthropogenic nss-SO 4 2− in the subarctic western North Pacific despite the higher mean concentration of MSA in the subarctic western North Pacific than in the South Pacific. [ABSTRACT FROM AUTHOR]

Number–size distributions of aerosol particles with diameters of 10–500 nm in the marine boundary layer were observed continually onboard the R/V Hakuho Maru over the equatorial and subtropical North Pacific and South Pacific during December 2011–March 2012. Number–size distributions over each area were parameterized using a sum of up to three lognormal functions. Bi-modal size distributions with peak diameters at 30–80 nm (Aitken mode) and 100–200 nm (accumulation mode) were observed frequently. Larger peak diameters of Aitken and accumulation modes were observed over the eastern equator, where 5-day backward trajectories showed that the air masses had derived from high-chlorophyll oceanic regions without precipitation. Smaller peak diameters and low concentrations were often observed over the North Pacific. The trajectories show that such air mass originated from oceanic regions with less chlorophyll, exhibiting high precipitation frequency. New particle formation (NPF) events have often been observed over the mid-latitude eastern South Pacific with a low condensation sink (CS) and some dimethyl sulfide, although none was observed over the equator, where CS was higher. The lesser CS condition at NPF events was mostly correlated with local precipitation or precipitation along the trajectories within 1 day. These results suggest that differences of the number–size distribution and occasions of NPF events among sea areas most closely accord with precipitation along the trajectories. [ABSTRACT FROM AUTHOR]