Remote Ocean Areas Research Articles

Diet of non-breeding leach’s storm-petrels (Hydrobates leucorhous) in the sub-polar frontal zone of the North Atlantic

In order to understand the drivers of the distribution and abundance of pelagic seabirds it is necessary to know what they eat, yet there remains little detailed, geo-referenced information on the diets of pelagic seabird. In particular, due to sampling difficulties, information is lacking for non-breeding stages, smaller species, such as storm-petrels, and remote oceanic areas, which may include important diversity hotspots. In this study, we aimed to characterize the trophic ecology of Leach’s storm-petrels foraging in the vicinity of the North Atlantic Current and Evlanov Seamount Marine Protected Area using a combination of survey methods. On a cruise undertaken in June 2017 to characterize the distribution and ecology of seabirds in the region, nineteen Leach’s storm-petrels were caught, sampled and released unharmed. Regurgitations and faecal samples were collected, as well as blood and feather tissues for stable isotope analyses. Of the 12 males, 6 females and 1 unsexed bird, 84% were in active flight feather moult, suggesting they were non-breeders. Prey species, assayed via molecular metabarcoding, were dominated by mesopelagic fish, principally lanternfishes (Myctophidae) and hatchetfishes (Sternoptychidae), but also included cephalopods and crustaceans. Additionally, almost half of the birds had microplastics in their regurgitates. Stable isotopic ratios did not differ significantly between sexes. Our results, combined with those of previous studies, suggest that within the oceanic North Atlantic, Leach’s storm-petrels feed at a similar trophic level to much larger seabirds, targeting mesopelagic fishes that are a key component of the North Atlantic pelagic food web.

Significant methane undersaturation during austral summer in the Ross Sea (Southern Ocean)

AbstractMethane (CH4) is a climate‐relevant trace gas that is emitted from the open and coastal oceans in considerable amounts. However, its distribution in remote oceanic areas is largely unknown. To fill this knowledge gap, dissolved CH4 was measured at nine stations at 75°S in the Ross Sea during austral summer in January 2020. CH4 undersaturation (mean: 82 ± 20%) was found throughout the water column. In subsurface waters, the distribution of CH4 mainly resulted from mixing of water masses and in situ consumption, whereas the CH4 concentrations in the surface mixed layer were mainly driven by air–sea exchange and diapycnal diffusion between the surface and subsurface layers, as well as consumption of CH4. With a mean air–sea CH4 flux density of −0.44 ± 0.34 μmol m−2 d−1, the Ross Sea was a substantial sink for atmospheric CH4 during austral summer, which is in contrast with most oceanic regions, which are known sources.

Sampling from commercial vessel routes can capture marine biodiversity distributions effectively.

Collecting fine-scale occurrence data for marine species across large spatial scales is logistically challenging but is important to determine species distributions and for conservation planning. Inaccurate descriptions of species ranges could result in designating protected areas with inappropriate locations or boundaries. Optimizing sampling strategies therefore is a priority for scaling up survey approaches using tools such as environmental DNA (eDNA) to capture species distributions. In a marine context, commercial vessels, such as ferries, could provide sampling platforms allowing access to undersampled areas and repeatable sampling over time to track community changes. However, sample collection from commercial vessels could be biased and may not represent biological and environmental variability. Here, we evaluate whether sampling along Mediterranean ferry routes can yield unbiased biodiversity survey outcomes, based on perfect knowledge from a stacked species distribution model (SSDM) of marine megafauna derived from online data repositories. Simulations to allocate sampling point locations were carried out representing different sampling strategies (random vs regular), frames (ferry routes vs unconstrained), and number of sampling points. SSDMs were remade from different sampling simulations and compared with the "perfect knowledge" SSDM to quantify the bias associated with different sampling strategies. Ferry routes detected more species and were able to recover known patterns in species richness at smaller sample sizes better than unconstrained sampling points. However, to minimize potential bias, ferry routes should be chosen to cover the variability in species composition and its environmental predictors in the SSDMs. The workflow presented here can be used to design effective sampling strategies using commercial vessel routes globally for eDNA and other biodiversity survey techniques. This approach has potential to provide a cost-effective method to access remote oceanic areas on a regular basis and can recover meaningful data on spatiotemporal biodiversity patterns.

Impact of preservation method and storage period on ribosomal metabarcoding of marine microbes: Implications for remote automated samplings.

Automated sampling technologies can enhance the temporal and spatial resolution of marine microbial observations, particularly in remote and inaccessible areas. A critical aspect of automated microbiome sampling is the preservation of nucleic acids over long-term autosampler deployments. Understanding the impact of preservation method on microbial metabarcoding is essential for implementing genomic observatories into existing infrastructure, and for establishing best practices for the regional and global synthesis of data. The present study evaluates the effect of two preservatives commonly used in autosampler deployments (mercuric chloride and formalin) and two extraction kits (PowerWater and NucleoSpin) on amplicon sequencing of 16S and 18S rRNA gene over 50 weeks of sample storage. Our results suggest the combination of mercuric chloride preservation and PowerWater extraction as most adequate for 16S and 18S rRNA gene amplicon-sequencing from the same seawater sample. This approach provides consistent information on species richness, diversity and community composition in comparison to control samples (nonfixed, filtered and frozen) when stored up to 50 weeks at in situ temperature. Preservation affects the recovery of certain taxa, with specific OTUs becoming overrepresented (SAR11 and diatoms) or underrepresented (Colwellia and pico-eukaryotes) after preservation. In case eukaryotic sequence information is the sole target, formalin preservation and NucleoSpin extraction performed best. Our study contributes to the design of long-term autonomous microbial observations in remote ocean areas, allowing cross-comparison of microbiome dynamics across sampling devices (e.g., water and particle samplers) and marine realms.

Simulating the radiative forcing of oceanic dimethylsulfide (DMS) in Asia based on machine learning estimates

Abstract. Dimethylsulfide (DMS) emitted from seawater is a key precursor to new particle formation and acts as a regulator in Earth's warming climate system. However, DMS's effects are not well understood in various ocean regions. In this study, we estimated DMS emissions based on a machine learning method and used the GEOS-Chem global 3D chemical transport model coupled with the TwO Moment Aerosol Sectional (TOMAS) microphysics scheme to simulate the atmospheric chemistry and radiative effects of DMS. The contributions of DMS to atmospheric SO42- aerosol and cloud condensation nuclei (CCN) concentrations along with the radiative effects over the Asian region were evaluated for the first time. First, we constructed novel monthly resolved DMS emissions (0.5∘×0.5∘) for the year 2017 using a machine learning model; 4351 seawater DMS measurements (including the recent measurements made over the Chinese seas) and 12 relevant environment parameters were selected for model training. We found that the model could predict the observed DMS concentrations with a correlation coefficient of 0.75 and fill the values in regions lacking observations. Across the Asian seas, the highest seasonal mean DMS concentration occurred in March–April–May (MAM), and we estimate the annual DMS emission flux of 1.25 Tg (S), which is equivalent to 15.4 % of anthropogenic sulfur emissions over the entire simulation domain (which covered most of Asia) in 2017. The model estimates of DMS and methane sulfonic acid (MSA), using updated DMS emissions, were evaluated by comparing them with cruise survey experiments and long-term online measurement site data. The improvement in model performance can be observed compared with simulation results derived from the global-database DMS emissions. The relative contributions of DMS to SO42- and CCN were higher in remote oceanic areas, contributing 88 % and 42 % of all sources, respectively. Correspondingly, the sulfate direct radiative forcing (DRF) and indirect radiative forcing (IRF) contributed by DMS ranged from −200 to −20 mW m−2 and from −900 to −100 mW m−2, respectively, with levels varying by season. The strong negative IRF is mainly over remote ocean regions (−900 to −600 mW m−2). Generally, the magnitude of IRF derived by DMS was twice as large as its DRF. This work provides insights into the source strength of DMS and the impact of DMS on climate and addresses knowledge gaps related to factors controlling aerosols in the marine boundary layer and their climate impacts.

Improved Bathymetric Prediction Using Geological Information: SYNBATH

AbstractTo date, ∼20% of the ocean floor has been surveyed by ships at a spatial resolution of 400 m or better. The remaining 80% has depth predicted from satellite altimeter‐derived gravity measurements at a relatively low resolution. There are many remote ocean areas in the southern hemisphere that will not be completely mapped at 400 m resolution during this decade. This study is focused on the development of synthetic bathymetry to fill the gaps. There are two types of seafloor features that are not typically well resolved by satellite gravity; abyssal hills and small seamounts (<2.5 km tall). We generate synthetic realizations of abyssal hills by combining the measured statistical properties of mapped abyssal hills with regional geology including fossil spreading rate/orientation, rms height from satellite gravity, and sediment thickness. With recent improvements in accuracy and resolution, it is now possible to detect all seamounts taller than about 800 m in satellite‐derived gravity and their location can be determined to an accuracy of better than 1 km. However, the width of the gravity anomaly is much greater than the actual width of the seamount so the seamount predicted from gravity will underestimate the true seamount height and overestimate its base dimension. In this study, we use the amplitude of the vertical gravity gradient (VGG) to estimate the mass of the seamount and then use their characteristic shape, based on well‐surveyed seamounts, to replace the smooth‐predicted seamount with a seamount having a more realistic shape.

Noise Levels and Signals Observed on Submarine Fibers in the Canary Islands Using DAS

Abstract In this study, we investigate 70 days of distributed acoustic sensing (DAS) recordings in the Canary Islands using an undersea fiber-optic telecommunication cable that links the islands of Tenerife and Gran Canaria. Two DAS interrogators connected to both ends of the cable turned the fiber into an array of 11,968 strain sensors covering a total length of ∼120 km. We present the details of the experiment, noise analysis, and examples of recorded signals. Seismic ambient noise levels assessment indicates poor local coupling of the cable due to the irregular bathymetry that results in high-amplitude acoustic oscillations in some channels. The DAS array recorded several types of nonseismic (vehicles, surface gravity waves, ships) and seismic signals. Local and regional earthquakes were detected with magnitudes mbLg≥2. Surface waves from teleseismic events at a distance of ∼3000 km were also identified in the strain recordings. Here, we report the first observations with DAS of hydroacoustic T waves generated by oceanic earthquakes located at the Central Mid-Atlantic Ridge and the Cape St. Vincent region. Events had magnitudes from Mw 4.2 to 6.9, and the hydroacoustic waves were recorded at epicentral distances from 780 to 3400 km. Our findings show that submarine fiber-optic cables can effectively be used to assess the seismic activity in remote oceanic areas.

Evaluation of aerosol and cloud properties in three climate models using MODIS observations and its corresponding COSP simulator, as well as their application in aerosol–cloud interactions

Abstract. The evaluation of modelling diagnostics with appropriate observations is an important task that establishes the capabilities and reliability of models. In this study we compare aerosol and cloud properties obtained from three different climate models (ECHAM-HAM, ECHAM-HAM-SALSA, and NorESM) with satellite observations using Moderate Resolution Imaging Spectroradiometer (MODIS) data. The simulator MODIS-COSP version 1.4 was implemented into the climate models to obtain MODIS-like cloud diagnostics, thus enabling model-to-model and model-to-satellite comparisons. Cloud droplet number concentrations (CDNCs) are derived identically from MODIS-COSP-simulated and MODIS-retrieved values of cloud optical depth and effective radius. For CDNC, the models capture the observed spatial distribution of higher values typically found near the coasts, downwind of the major continents, and lower values over the remote ocean and land areas. However, the COSP-simulated CDNC values are higher than those observed, whilst the direct model CDNC output is significantly lower than the MODIS-COSP diagnostics. NorESM produces large spatial biases for ice cloud properties and thick clouds over land. Despite having identical cloud modules, ECHAM-HAM and ECHAM-HAM-SALSA diverge in their representation of spatial and vertical distributions of clouds. From the spatial distributions of aerosol optical depth (AOD) and aerosol index (AI), we find that NorESM shows large biases for AOD over bright land surfaces, while discrepancies between ECHAM-HAM and ECHAM-HAM-SALSA can be observed mainly over oceans. Overall, the AIs from the different models are in good agreement globally, with higher negative biases in the Northern Hemisphere. We evaluate the aerosol–cloud interactions by computing the sensitivity parameter ACICDNC=dln⁡(CDNC)/dln⁡(AI) on a global scale. However, 1 year of data may be considered not enough to assess the similarity or dissimilarities of the models due to large temporal variability in cloud properties. This study shows how simulators facilitate the evaluation of cloud properties and expose model deficiencies, which are necessary steps to further improve the parameterisation in climate models.

Microplastic abundance, distribution and composition in the mid-west Pacific Ocean

Microplastic pollution is widespread across most ocean basins around the world. Microplastics (MPs) are small plastic particles that have a significant impact on the marine environment. Various research on plastic pollution have been conducted in several regions. However, currently, there is limited data on the distribution and concentration of MPs in the mid-west Pacific Ocean. Therefore, this study we investigated the abundance, distribution, characteristics, and compositions of MPs in this region. Sea surface water samples collected from 18 stations showed a microplastic concentration range of 6028–95,335 pieces/km2 and a mean concentration of 34,039 ± 25,101 pieces/km2. Highest microplastic concentrations were observed in the seamount region of western Pacific. We observed a significant positive correlation between microplastic abundance and latitude across the study region. It was observed that microplastic concentrations decreased with increasing offshore distance at sites located on a 154° W transect. Fibres/filaments were the dominant microparticles observed in this study (57.4%), followed by fragments (18.3%). The dominant particle size range was 1–2.5 mm (35.1%), followed by 0.5–1 mm (28.5%), and the dominant particle colour was white (33.8%), followed by transparent (31.0%) and green (24.6%). The most common polymer identified by μ-Raman was polypropylene (39.1%), followed by polymethyl methacrylate (16.2%), polyethylene (14.1%) and polyethylene terephthalate (14.2%). The possible sources and pathways of microplastics in the study area were proposed based on the morphological and compositional characteristics of particles, their spatial distribution patterns, and shipboard current profiling (ADCP). Our study contributes to the further understanding of MPs in remote ocean areas.

Precipitable water vapor over oceans from the Maritime Aerosol Network: Evaluation of global models and satellite products under clear sky conditions

We present results from an evaluation of precipitable water vapor (W) over remote oceanic areas as derived from global reanalysis models and from satellites against observations from the Maritime Aerosol Network (MAN) for cloudless skies during the period of 2004–2017. They cover polar, mid latitude and tropical oceanic regions and represent a first effort to use MAN observations for such evaluation. The global reanalysis model products evaluated in this study are from the Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2), the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA I), and the Climate Forecast System Reanalysis (CFSR) model. The satellite products evaluated are from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Polarization and Directionality of the Earth's Reflectances (POLDER), the Global Ozone Monitoring Experiment (GOME-2), the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and the Atmospheric Infra-red Sounder (AIRS). Satellite retrievals of W are based on the attenuation of solar reflected light by water vapor absorption bands, except those from AIRS that rely on brightness temperature measurements. A very good agreement is observed between the model estimates and MAN, with mean differences of ~5% and standard deviations of ~15%. These results are within the uncertainties associated with the models and the measurements, indicating the skill of the reanalysis models to estimate W over oceans under clear sky conditions. Mean differences of W between the satellite and MAN products are ~11, 6.7, 12, −7, and 3% for MODIS, POLDER, GOME-2, SCIAMACHY and AIRS respectively, while their standard deviations are 31, 29, 28, 20 and 17%. These differences reveal the need to address inconsistencies among different satellite sensors and ground-based measurements to reduce the uncertainties associated with the retrievals.

Morphological features and mixing states of soot-containing particles in the marine boundary layer over the Indian and Southern oceans

Abstract. Mixing states of soot-containing aerosol particles constitute important information for the simulation of climatic effects of black carbon in the atmosphere. To elucidate the mixing states and morphological features of soot-containing particles over remote oceans, we conducted on-board observations over the southern Indian Ocean and the Southern Ocean during the TR/V Umitaka-maru UM-08-09 cruise, which started from Benoa, Indonesia, on 1 December 2008 via Cape Town, South Africa, and which terminated in Fremantle, Australia, on 6 February 2009. The light absorption coefficients of size-segregated particles (< 0.5 and < 1.0 µm diameter) and aerosol number concentrations (0.1–0.5 µm diameter) were measured to assist direct aerosol sampling. Size-segregated aerosol particles were collected for chemical analysis using ion chromatography. For transmission electron microscopy (TEM) analyses using water-dialysis methods, dried submicrometer aerosol particles were collected using a cascade impactor. We analyzed 13 TEM samples. Results of water-dialysis analysis demonstrate that most particles were water-soluble. However, for all TEM samples, particles were rarely found (2.1 % of particles on a TEM sample at a maximum) containing insoluble residuals with the characteristic soot shape. For samples collected over the Indian and Southern oceans at latitudes less than 62∘ S, some (20–35 %) soot-containing particles were found as bare soot. For samples collected near the Antarctic coast (65–68∘ S, 38–68∘ E), all soot-containing particles were mixed with water-soluble materials. Furthermore, 56 % of soot-containing particles had a satellite structure formed by the impact of droplets such as sulfuric acid. Chemical analysis of submicrometer particles near the Antarctic coast revealed high concentrations of non-sea-salt (nss) SO42- and CH3SO3-, suggesting that aged soot-containing particles were transformed by soluble materials derived from dimethyl sulfide (DMS) oxidation. The obtained information of soot at various remote ocean areas is expected to be useful to understand long-range transport processes and to improve simulations of global soot concentration.

Corporate control and global governance of marine genetic resources.

Who owns ocean biodiversity? This is an increasingly relevant question, given the legal uncertainties associated with the use of genetic resources from areas beyond national jurisdiction, which cover half of the Earth's surface. We accessed 38 million records of genetic sequences associated with patents and created a database of 12,998 sequences extracted from 862 marine species. We identified >1600 sequences from 91 species associated with deep-sea and hydrothermal vent systems, reflecting commercial interest in organisms from remote ocean areas, as well as a capacity to collect and use the genes of such species. A single corporation registered 47% of all marine sequences included in gene patents, exceeding the combined share of 220 other companies (37%). Universities and their commercialization partners registered 12%. Actors located or headquartered in 10 countries registered 98% of all patent sequences, and 165 countries were unrepresented. Our findings highlight the importance of inclusive participation by all states in international negotiations and the urgency of clarifying the legal regime around access and benefit sharing of marine genetic resources. We identify a need for greater transparency regarding species provenance, transfer of patent ownership, and activities of corporations with a disproportionate influence over the patenting of marine biodiversity. We suggest that identifying these key actors is a critical step toward encouraging innovation, fostering greater equity, and promoting better ocean stewardship.

Interactions of tuna fisheries with the Galápagos marine reserve

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 585:1-15 (2017) - DOI: https://doi.org/10.3354/meps12399 FEATURE ARTICLE Interactions of tuna fisheries with the Galápagos marine reserve Kristina Boerder*, Andrea Bryndum-Buchholz, Boris Worm Biology Department, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada *Corresponding author: kristina.boerder@dal.ca ABSTRACT: The largest protected areas of any kind have all recently been established in the ocean. Since 2012, 5 protected areas that exceed 1 million km2 in size have been created, mostly in remote oceanic areas. The potential conservation and fisheries benefits of such reserves have been debated in the public, the media, and the scientific literature. Little is known about their effectiveness for commercially valuable pelagic predators, especially for highly migratory species such as tuna and billfishes. Here we analyse the iconic Galápagos Marine Reserve, documenting interactions with and changes in associated tuna purse seine fisheries in the Eastern Tropical Pacific. Using a combination of long-term onboard observer data and a novel data set of high-resolution, remotely sensed vessel tracks (Automatic Identification System [AIS]), we reveal progressive divergence of tuna fishing effort, catch, and catch per unit of effort (CPUE) trends in areas adjacent to the reserve from trends in the surrounding fished areas. Both data sets show a regionally unique hotspot of concentrated effort along the western reserve boundary now receiving >4-fold greater fishing effort density than the rest of the surrounding area. These dynamic interactions of tuna purse seine fisheries with the Galápagos Marine Reserve suggest that the reserve might enhance fish stock availability to local fisheries and help to stabilize local catches despite overall decreasing biomass trends for these highly commercial tuna stocks. KEY WORDS: Marine protected area · Pelagic fisheries · Tuna · AIS · FADs · Purse seine Full text in pdf format Information about this Feature Article Supplementary material NextCite this article as: Boerder K, Bryndum-Buchholz A, Worm B (2017) Interactions of tuna fisheries with the Galápagos marine reserve. Mar Ecol Prog Ser 585:1-15. https://doi.org/10.3354/meps12399 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 585. Online publication date: December 22, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.

A potential large and persistent black carbon forcing over Northern Pacific inferred from satellite observations

Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC’s climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R2 > 0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the mid-Pacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is seen over the Northern Pacific, with abundances varying consistently with the springtime Pacific/North American (PNA) index. Our sBC* dataset infers a widespread overestimation of BC loadings and BC Direct Radiative Forcing by current models over North Pacific, which further suggests that large uncertainties exist on aerosol-climate interactions over other remote oceanic areas beyond Pacific.

Cephalopod fauna of South Pacific waters: new information from breeding New Zealand wandering albatrosses

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 513:131-142 (2014) - DOI: https://doi.org/10.3354/meps10957 Cephalopod fauna of South Pacific waters: new information from breeding New Zealand wandering albatrosses José C. Xavier1,2,*, Kath Walker3, Graeme Elliott3, Yves Cherel4, David Thompson5 1Institute of Marine Research, Department of Life Sciences, University of Coimbra, 3001-401 Coimbra, Portugal 2British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, CB3 0ET Cambridge, UK 3Albatross Research, 594 Rocks Road, Nelson 7011, New Zealand 4Centre d’Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360 Villiers-en-Bois, France 5National Institute of Water and Atmospheric Research Ltd., 301 Evans Bay Parade, Hataitai, Wellington 6021, New Zealand *Corresponding author: jccx@cantab.net ABSTRACT: Cephalopods play an important ecological role in the Southern Ocean, being the main prey group of numerous top predators. However, their basic ecology and biogeography is still poorly known, particularly in the lightly sampled Pacific sector of the Southern Ocean. We collected and analysed information on cephalopods in that area, using Antipodean and Gibson’s wandering albatrosses (Diomedea antipodensis antipodensis and D. antipodensis gibsoni, respectively) breeding at Antipodes Islands and Auckland Islands, respectively, in the New Zealand subantarctic islands as samplers, as they are known from tracking studies to cover huge areas of the Pacific sector of the Southern Ocean (Antipodean wandering albatrosses mostly forage east of New Zealand, whereas Gibson’s wandering albatrosses forage west of New Zealand). A total of 9111 cephalopod beaks, from 41 cephalopod taxa, were identified from boluses (voluntarily regurgitated items by chicks). The families Histioteuthidae (e.g. Histioteuthis atlantica) and Onychoteuthidae (e.g. Moroteuthis robsoni) were the most important cephalopods numerically and by reconstructed mass, respectively, in both wandering albatross species. Combining this information with previously gathered data on cephalopods in the Atlantic and Indian sectors of the Southern Ocean, we provide evidence from predators of the circumpolar distribution of numerous key cephalopod species in the Southern Ocean, and provide new information on poorly known cephalopods (i.e. relevance in the diet of wandering albatrosses, sizes consumed, biodiversity in the South Pacific, assemblages according to predator breeding sites) in one of the most remote ocean areas in the planet. KEY WORDS: Squid · Histioteuthidae · Onychoteuthidae · Distribution · Biodiversity · Predatory sampling · Diomedea antipodensis · Seabird · Southern Ocean Full text in pdf format Supplementary material PreviousNextCite this article as: Xavier JC, Walker K, Elliot G, Cherel Y, Thompson D (2014) Cephalopod fauna of South Pacific waters: new information from breeding New Zealand wandering albatrosses. Mar Ecol Prog Ser 513:131-142. https://doi.org/10.3354/meps10957 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 513. Online publication date: October 22, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Atmospheric Black Carbon along a Cruise Path through the Arctic Ocean during the Fifth Chinese Arctic Research Expedition

From July to September 2012, during the fifth Chinese National Arctic Research Expedition (CHINARE), the concentrations of black carbon (BC) aerosols inside the marine boundary layer were measured by an in situ aethalometer. BC concentrations ranged from 0.20 ng∙m−3 to 1063.20 ng∙m−3, with an average of 75.74 ng∙m−3. The BC concentrations were significantly higher over the mid-latitude and coastal areas than those over the remote ocean and high latitude areas. The highest average concentration was found over offshore China (643.44 ng∙m−3) during the cruise, while the lowest average was found over the Arctic Ocean (5.96 ng∙m−3). BC aerosol was found mainly affected by the terrestrial input and displayed seasonal and spatial variations. Compared with the results from the third and fourth CHINARE of summer 2008, and summer 2010, the inter-annual variation of BC over the Arctic Ocean was negligible.

Feasibility analysis of offshore renewables penetrating local energy systems in remote oceanic areas – A case study of emissions from an electricity system with tidal power in Southern Alaska

In many remote areas, expensive fossil fuels such as diesel are used to meet local electricity demand. However, their environmental impact is significant. Consequently, some of these areas have started to use hybrid systems that combine renewable energy sources and fossil fuel generation, such as wind-diesel systems, although wind is not feasible in some remote locations and fossil fuels remain the only resource in these areas. Fortunately, offshore renewable energy sources are available in many remote areas close to the ocean. In order to understand the feasibility of using offshore renewables in remote oceanic areas, we recently conducted a systematic study by developing an integrated model. This model includes a supply module, demand module, environmental impact module, and integrating module. Using this model, we mainly study the reduction in emissions resulting from offshore renewable energy penetration in local energy systems. In this article, we present this integrated model and an example study of tidal energy in the Southern Alaska community of Elfin Cove, which relies on diesel fuel for all of its electricity requirements. With 56kW of tidal power penetrating the energy system, we found that almost 12,000 gallons of diesel fuel are displaced per year. This results in an annual emissions reduction of almost 244,000lb CO2 and about 1400lb CO, as well as considerable reductions of PM-10, NOx, and SOx. The newly developed integrated model is expected to be used to analyze other aspects of tidal energy (and offshore renewable energy in general) in remote areas. For example, since the electricity demand in some remote areas varies significantly throughout the year, we recommend that tidal power should be used with a storage system.

Eolian transport of glycerol dialkyl glycerol tetraethers (GDGTs) off northwest Africa

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) of purportedly terrestrial origin are frequently detected in marine sediments, even in remote ocean sites where no direct impact from land erosion via rivers takes place. At these places, the most likely explanation for the presence of brGDGTs is in situ production or eolian transport, but neither possibility has been demonstrated for the open ocean. Here, we report the presence of isoprenoid (iso) and brGDGTs in eight dust samples collected off Northwest Africa. Based on previous studies, prevailing wind patterns, bulk chemistry, n-alkane composition and isotopic signatures, we show that Northwest Africa is the likely principal origin of the GDGTs in the dust. The concentrations of plant wax n-alkanes in the dust are several orders of magnitude higher than those of GDGTs and, based on the distributions of these two compound classes, we infer that they tag different carbon pools and sources of organic matter. Our finding demonstrates that brGDGTs and isoGDGTs in marine sediments and wind-derived deposits can have an eolian source. Consequently, climate reconstruction may be attempted from wind-derived deposits of brGDGTs, even in remote oceanic areas.

Detection of small earthquakes along the Pacific-Antarctic Ridge from T-waves recorded by abyssal ocean-bottom observatories

A number of seismoacoustic T-wave events were observed between January 2003 and January 2004 by broadband ocean-bottom seismometers installed on the French Polynesia seafloor at depths of 4,000–5,000 m, well below the conjugate depth of the SOFAR channel. Using T-wave arrival times, we located 89 T-wave events along the Pacific-Antarctic Ridge. Among these, 63 events were not detected by land-based seismic observations of the United States Geological Survey (USGS), which was nearly twice the number of earthquakes reported by the USGS in the area during the observation period. We used a simple method to estimate earthquake magnitude from T-wave energy. The magnitudes of the events unidentified by the USGS ranged from 2.3 to 5.5, whereas magnitudes of the earthquakes reported by the USGS ranged from 4.1 to 6.2. Our study suggests that T-wave observations with abyssal ocean-bottom seismometers can improve the detection of small earthquakes and help our understanding of the seismotectonics of remote oceanic areas.

Strengthening of North American dust sources during the late Pliocene (2.7 Ma)

Here we present orbitally-resolved records of terrestrial higher plant leaf wax input to the North Atlantic over the last 3.5Ma, based on the accumulation of long-chain n-alkanes and n-alkanl-1-ols at IODP Site U1313. These lipids are a major component of dust, even in remote ocean areas, and have a predominantly aeolian origin in distal marine sediments. Our results demonstrate that around 2.7million years ago (Ma), coinciding with the intensification of the Northern Hemisphere glaciation (NHG), the aeolian input of terrestrial material to the North Atlantic increased drastically. Since then, during every glacial the aeolian input of higher plant material was up to 30 times higher than during interglacials. The close correspondence between aeolian input to the North Atlantic and other dust records indicates a globally uniform response of dust sources to Quaternary climate variability, although the amplitude of variation differs among areas. We argue that the increased aeolian input at Site U1313 during glacials is predominantly related to the episodic appearance of continental ice sheets in North America and the associated strengthening of glaciogenic dust sources. Evolutional spectral analyses of the n-alkane records were therefore used to determine the dominant astronomical forcing in North American ice sheet advances. These results demonstrate that during the early Pleistocene North American ice sheet dynamics responded predominantly to variations in obliquity (41ka), which argues against previous suggestions of precession-related variations in Northern Hemisphere ice sheets during the early Pleistocene.