Novel deep-sea commensalism: a new genus and two new species of Myzostomida from the abyssal Pacific Ocean.

Exploration of mineral resources in the deep sea has become an international trend. However, deep-sea mineral exploration faces challenges such as complex offshore drilling and the weak and mixed signals of ore deposits. Therefore, studying methods for identifying weak and mixed anomalies and extracting composite information in the deep sea is crucial for innovative prediction and evaluation of deep-sea mineral resources. In this study, the Central Pacific Ocean, Northwestern Pacific Ocean, and Eastern Pacific Ocean were selected as research areas. Drawing upon the fractal self-similarity exhibited by rare earth minerals in the deep-sea sediments within the Pacific Ocean, we conducted an analysis and comparison of the fractal geochemical characteristics in various regions of the Pacific Ocean’s deep-sea sediments. Thereafter, we studied the spatial distribution of rare earth elements (REEs) in deep-sea sediments in these regions to explore the mechanisms responsible for rare earth enrichment in the Pacific Ocean. The results revealed that the geochemical fractal characteristics of deep-sea sediments in the Northwestern Pacific Ocean Basin and the Central Pacific Ocean Basin were similar, whereas there were slight differences in the fractal characteristics observed in the Eastern Pacific Ocean Basin. By calculating the singularity index of CaO/P2O5, it was found that the singularity index in the Central and Northwestern Pacific Ocean basins was lower than that in the Eastern Pacific Ocean Basin, suggesting that the phosphorus content in the Eastern Pacific Ocean Basin was lower than that in the Central and Northwestern Pacific Ocean basins. In the Eastern Pacific Ocean, we found that phosphorus content in deep-sea sediments was the primary controlling factor for REE enrichment. Conversely, in the Central and Northwestern Pacific Ocean, both the phosphorus and calcium content in deep-sea sediments played significant roles in REE enrichment.

Anomalies of sea surface temperature (SST) and heat storage in the upper 400 m of ocean (HS400) for 13 years from 1979 to 1991 are mapped onto a 2° latitude by 5° longitude grid each month over most of the global ocean from 30°S to 60°N. Time sequences at every grid location are band pass filtered to reveal El Niño‐Southern Oscillation (ENSO) signals on period scales ranging from 2 to 7 years. Time‐distance diagrams are constructed along the equator and eastern boundary of the North Pacific, North Atlantic, and South Indian Oceans. These time‐distance diagrams display slow poleward propagation of equatorial ENSO signals, consistently in HS400 and intermittently in SST. In the North Pacific Ocean, ENSO signals in HS400 take 9–18 months to propagate from the equator northward along the west coast of North America to the Gulf of Alaska. In the North Atlantic Ocean, ENSO signals in HS400 take 6–12 months to propagate from the equator along the west coast of Africa to the Strait of Gibraltar. In the South Indian Ocean, ENSO signals in HS400 take 9–18 months to propagate poleward from the equator along the west coasts of Indonesia and Australia to Perth. Speeds of poleward propagation of ENSO waves in both HS400 and SST along these eastern boundaries range from 5 to 30 cm s−1. These ENSO boundary waves propagate in the same direction as Kelvin waves, but with speeds an order of magnitude smaller. They provide a remote and delayed influence upon ENSO activity in the middle‐latitude eastern boundary in each ocean. Time‐distance diagrams are also constructed along the western boundary and equator of the North Pacific, North Atlantic, and South Pacific Oceans. These time‐distance diagrams display slow propagation of ENSO signals in SST and HS400 in both directions depending on the ocean. In the North Pacific Ocean, ENSO signals in both SST and HS400 propagate equatorward from Taiwan to New Guinea, taking 6–18 months to make this transit. Moreover, they arrive on the equator in phase with zonally propagating equatorial ENSO waves. This indicates that ENSO activity in the western subtropical North Pacific Ocean influences ENSO activity in the western equatorial Pacific Ocean through slow equatorward propagation. Speeds of equatorward propagation of ENSO waves in both HS400 and SST along this western boundary range from 5 to 20 cm s−1. In the North Atlantic and South Pacific Oceans this off‐equatorial influence is not possible, since slow ENSO waves in HS400 propagate poleward along these western boundaries.

On the influence of the Norwegian-Greenland and Weddell seas upon the bottom waters of the Indian and Pacific oceans

Salinity, oxygen, inorganic phosphorus, organic and inorganic carbon, carbonate alkalinity, insoluble carbonate, and radiocarbon are used simultaneously as tracers to investigate oceanic circulation, chemical processes within the ocean and chemical exchange at oceanic boundaries. Estimates of the rates of these processes are made using the equation for chemical transport in the simplest approximation which recognizes spatially variable exchange at the ocean-atmosphere boundary, horizontal and vertical advective and eddy diffusive transport, and gravitational settling of insoluble chemicals within the oceans. This approximation is a cyclic model with one atmospheric and three oceanic reservoirs between which tracers exchange by first-order kinetics. Data for the Pacific Ocean are used after having been averaged over time and the regions: warm surface water, cold surface water, and deep water. Northern and southern cold surface waters are treated as alternate cases. We deduce that: 1 The mass of deep water in the Pacific Ocean divided by its rate of production is about 1100 years, a time interval in close agreement with its average radiocarbon age relative to that of cold surface water. 2 In the South Pacific Ocean, the transfer of water between the deep ocean and the surface is principally by exchange with cold surface water. A small net circulation from warm surface water to cold surface water is suggested by the model, but the rate cannot be calculated with existing information. 3 The three-reservoir model cannot, even to a first approximation, explain the circulation of the North Pacific Ocean, because it overlooks the flow of deep water into the North Pacific Ocean from the South Pacific Ocean. 4 Both oxygen and carbon dioxide are evolved from surface waters at low latitudes and absorbed at high latitudes. The rates of exchange from warm surface water to cold surface water are of the order of 10 17 mmol yr ?1 . 5 About 10% of the inorganic carbon in deep water arrives there from surface water by gravitational settling of organic carbon and insoluble carbonate. The other 90% is transported there by the water itself. 6 The use of pH measurements to assay for dissolved inorganic carbon and alkalinity seriously limits the reliability of carbon data in the present study. Small errors in pH result in large uncertainties in the deduced rates of gravitational transport of organic carbon and insoluble carbonates and in the rate of exchange of CO 2 with the atmosphere. DOI: 10.1111/j.2153-3490.1968.tb00348.x

A deeper respired carbon pool in the glacial equatorial Pacific Ocean

Mercury distributions in the North Pacific Ocean—20 years of observations

Tropical cyclones (TCs) are an important component of the hydrological cycle at tropical latitudes. In this study, we investigated the origin of precipitation associated with TCs formed from 1980 to 2018 over the Pacific Ocean in three subbasins: the western North Pacific Ocean (WNP), central and east Pacific Ocean (NEPAC), and South Pacific Ocean (SPO) basins. The analysis was performed throughout the TC lifetime during genesis, when they reached the lifetime maximum intensity (LMI), and the dissipation stage. The backward trajectories of all precipitant atmospheric parcels residing over the TC locations from the global outputs of the Lagrangian Flexible Particle (FLEXPART) dispersion model fed by the ERA-Interim dataset were used to identify moisture sources. The South and East China Seas and the western tropical North Pacific Ocean were identified as the principal moisture sources in the WNP basin, while the atmospheric moisture that precipitated mainly came from the eastern tropical North and South Pacific Ocean in the NEPAC basin, followed by the Caribbean Sea. Meanwhile, the Coral Sea, western tropical South Pacific Ocean, and northern Australia are the origins of the moisture in the SPO. The mean moisture uptake per TC was higher during the hurricane category than during any other stage in each basin.

(introduction to Special Issue: The roles of habitat heterogeneity in generating and maintaining biodiversity on continental margins A Contribution to the Census of Marine Life)

Stable isotope ratios and mercury levels in red meat products from baleen whales sold in Japanese markets

Evidence for hydrothermal venting in Fe isotope compositions of the deep Pacific Ocean through time

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (coplanar PCBs) were determined in five albatross species collected from the North Pacific and Southern Oceans to assess the north-south differences in residue levels, accumulation patterns, and toxic potential. Black-footed and Laysan albatrosses from the North Pacific Ocean contained higher levels of PCDD/Fs and coplanar PCBs than albatrosses from the Southern Ocean, indicating that emission sources of these contaminants were predominant in the northern hemisphere. Residue levels in albatrosses from the remote North Pacific Ocean far from the point source of pollution were comparable to or higher than those in terrestrial and coastal birds from contaminated areas in developed nations, suggesting the specific exposure and accumulation of PCDD/Fs and coplanar PCBs in albatross. The long life span and ingestion of plastic resin pellets by albatrosses could be the plausible explanations for the elevated accumulation of persistent and lipophilic contaminants including PCDD/Fs and coplanar PCBs in these birds. Relative proportions of PCDFs and coplanar PCBs in albatross were higher than those observed in birds inhabiting terrestrial and coastal areas, suggesting that these toxic chemicals may have higher transportability by air and water than PCDDs. Congener patterns of PCDD/Fs in albatross showed less variability as compared to those in terrestrial species, indicating that contamination patterns of PCDD/Fs were similar within the open ocean environment. Contributions of PCDD/Fs to total TEQs in albatrosses from the open ocean were generally lower than those in terrestrial birds, suggesting different toxic potency of PCDD/Fs and coplanar PCBs on animals inhabiting open ocean and terrestrial environment. Whereas albatrosses from southern oceans retained lower TEQ concentrations, possible adverse effects of PCDD/Fs and coplanar PCBs to black-footed and Laysan albatrosses of the North Pacific Ocean may be suspected from TEQ levels.

The goal was to synthesize the literature on wildland fires, how they create resilient landscape mosaics that affect ecosystem function and maintenance of biodiversity, and how the fires themselves are affected by wilderness edge effects and climate change. The emphasis is on cold-temperate and boreal forests. The interactions of fires with landforms create large-magnitude spatial and temporal heterogeneity in fire severity that cannot be seen in smaller natural areas. Patterns of live and dead biomass and characteristic syndromes of fire-species interactions determine future successional trajectories and spatial-temporal dynamics of landscape mosaics. Therefore, wildlands with freely occurring fires provide a scientific baseline for complexity of vegetation structure and maintenance of biodiversity and ecosystem processes on time scales from years to centuries and millennia. Although wildlands are impacted by climate change, they may have considerable resilience, partly due to fire occurrence, and may still serve as a moving baseline. Thus, the patterns observed in wildlands can be used as blueprints for restoration of landscape structure, biodiversity, and ecosystem function in human-dominated ecosystems. Wildland fires play an important role in maintenance of ecological function and biodiversity, even on landscapes where fire is considered to be rare. At time scales of centuries, fires in large wilderness areas maintain a balance among successional stages, and although early and late-successional stages are rarely absent, their occurrences change in space and time, possibly leading to metapopulation dynamics for species that depend on certain successional stages. Over thousands of years, fires influence the trajectory of ecosystem retrogression, and in cold climates, fires can prevent ecosystem acidification that reduces forest productivity. Fire regimes within large wildlands are subject to change caused by fragmentation effects at large spatial extents; this can result in increased or reduced fire frequencies (disturbance dilution effect) within wildlands. Wildland managers need to think about how changes in the surrounding landscape influence the integrity of the natural disturbance baseline, while forest managers need to think about how harvesting compares to the baseline with respect to maintenance of productivity and biodiversity.

The meridional overturning circulation influences the deep‐sea carbon reservoir, global carbon cycle, and climate change on century to millennium time scales. However, the influence of deep‐sea circulation on sedimentary carbonate accumulation and thus deep‐sea carbonate system in the North Pacific Ocean is difficult to quantify owing to the complicated geometry of deep ocean ventilation attributed to its topographic complexity. In this study, we reanalyzed the distribution patterns of sedimentary calcium carbonate contents (wtCaCO3%) in the deep Northeast Pacific in a quantitative manner. Our results in conjunction with data from the Northwest Pacific Ocean, suggest that the deep ocean circulation plays a critical role in elucidating the basin‐scale features of sedimentary CaCO3 distribution in the North Pacific Ocean, despite elevated non‐carbonate dilution exerted by detritus from active geological processes on the topographic structure. Moreover, enhanced carbonate dissolution in the Guatemala and Panama Basins, controlled by higher flow rates of deep currents, influences the depth‐profiles of sedimentary wtCaCO3% in that region. These findings suggest a novel avenue to reconstruct past changes in ocean circulation and carbon cycling in the Northeast Pacific Ocean based on the wtCaCO3% records in sediments.

The study of oceanic microbial communities is crucial for our understanding of the role of microbes in terms of biomass, diversity and ecosystem function. In this study, 16S rRNA gene tag pyrosequencing was used to investigate change in bacterial community structure between summer and winter water masses from Gosung Bay in the South Sea of Korea and Chuuk in Micronesia, located in the North and South Pacific Oceans, respectively. Summer and winter sampling from each water mass revealed highly diverse bacterial communities, containing ~900 Operational Taxonomic Units (OTUs). The microbial distribution and highly heterogeneous composition observed at both sampling sites were different from those of most macroorganisms. The bacterial communities in the seawater at both sites were most abundant in Proteobacteria during the summer in Gosung and in Bacterioidetes during the winter. The proportion of Cyanobacteria was higher in summer than in winter in Chuuk and similar in Gosung. Additionally, the microbial community during summer in Gosung was significantly different from other communities observed based on the unweighted UniFrac distance. These data suggest that in both oceanic areas sampled, the bacterial communities had distinct distribution patterns with spatially- and temporally-heterogeneous distributions.

The Redfield ratio [carbon:nitrogen:phosphorus (C:N:P)] of particle flux to the deep ocean is a key factor in marine biogeochemical cycling. Changes in oceanic carbon sequestration have been linked to variations in the Redfield ratio on geological time scales, but this ratio generally is assumed to be constant with time in the modern ocean. However, deep-water Redfield ratios in the northern hemisphere show evidence for temporal trends over the past five decades. The North Atlantic Ocean exhibits a rising N:P ratio, which may be related to increased deposition of atmospheric nitrous oxides from anthropogenic N emissions. In the North Pacific Ocean, increasing C:N and C:P ratios are accompanied by rising remineralization rates, which suggests intensified export production. Stronger export of carbon in this region may be due to enhanced bioavailability of aeolian iron. These findings imply that the biological part of the marine carbon cycle currently is not in steady state.