Remote Oceanic Research Articles

Human Settlement and Landscape Anthropization of Remote Oceanic Islands: A Comparison between Rapa Nui (Pacific Ocean) and the Azores (Atlantic Ocean).

The flora and vegetation of oceanic islands have been deeply affected by human settlement and further landscape modifications during prehistoric and historical times. The study of these transformations is of interest not only for understanding how current island biotas and ecological communities have been shaped but also for informing biodiversity and ecosystem conservation. This paper compares two oceanic insular entities of disparate geographical, environmental, biological, historical and cultural characteristics-Rapa Nui (Pacific Ocean) and the Azores Islands (Atlantic Ocean)-in terms of human settlement and further landscape anthropization. The similarities and differences between these islands/archipelagos are discussed considering their permanent colonization, the possibility of earlier settlements, the removal of the original forests and the further landscape transformations leading to either full floristic/vegetational degradation (Rapa Nui) or major replacement (Azores). This comparison uses evidence from varied disciplines, notably paleoecology, archaeology, anthropology and history, to obtain a holistic view of the development of the respective socioecological systems from a human ecodynamic perspective. The most relevant issues still to be resolved are identified and some prospects for future research are suggested. The cases of Rapa Nui and Azores Islands may help set a conceptual basis for ocean-wide global comparisons among oceanic islands/archipelagos.

Estimating the Wind Dependency of Aerosol Optical Depth at Remote Oceanic Regions

In this article, the applicability of India’s indigenously developed scatterometer, Scatsat-1 for marine aerosol characterization and wind dependency of aerosol optical depth (AOD) was investigated using 3 years of satellite data. Wind data from Scatsat-1 and AOD with its size fraction from SNPP VIIRS from 2017 to 2019 were used for the investigation. A technique has been demonstrated for identifying remote oceanic regions with mostly marine aerosol using certain criteria like distance from land, higher fraction of coarse AOD, lower variation of AOD with wind direction, and so forth. Daily wind and AOD from 2017 to 2019 were used for studying the relationship between wind speed and AOD at remote oceanic locations away from terrestrial and anthropogenic influence. Five regions of interest (ROIs) of 5° by 5° were identified in different oceanic regions for carrying out the regression analysis. A linear increase of coarse mode AOD and total AOD with an increase in wind speed was observed for all five remote locations while fine mode AOD was unrelated. The slope of the linear relation agreed with Kiliyanpilakkil and Meskhidze (2011) for intermediate wind values. The remote regions also had a lower variation of AOD with change in wind direction implying less transport of aerosol from nearby landmasses.

Slope and Shelf Flow Anomalies Off Oregon Influenced by the El Niño Remote Oceanic Mechanism in 2014–2016

AbstractOutputs of the regional ocean circulation model are analyzed to demonstrate the measurable impact of the El Niño remote oceanic forcing mechanism along the US West Coast during the major heat wave period of 2014–2016. The 2‐km horizontal resolution model, based on the Regional Ocean Modeling System (ROMS), was run for the period of 2009–2018. Though the model does not assimilate observations, it performs well by comparison with time series data explaining observed variability on temporal scales from several days to seasonal and interannual. The El Niño‐related oceanic anomalies provided by a global state estimate are introduced in the regional model at the southern boundary at 24N. These propagate alongshore with coastally trapped waves (CTWs) and influence the variability off Oregon (41°–46°N). In particular, CTWs are evident in the subsurface along‐slope current, vs, and in the depth of the 26.5 kg m−3 isopycnal surface over the slope, z26.5. In summer 2014 and 2015, vs anomalies are positive (northward) and z26.5 anomalies are negative (deeper) along the US West Coast. In addition to the CTW patterns, z26.5 anomalies also exhibit slow‐moving features associated with undercurrent widening, separation, and subsurface eddy variability. Over the Oregon shelf, El Niño conditions contributed to the sharp weakening of the southward alongshore current throughout the water column in July 2014 and 2015, despite the near‐average southward, upwelling‐favorable winds.

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.

Hypotheses to explain the few early coastal archaeological deposits in Sāmoa: Preliminary evaluations

The Remote Oceanic archipelagos from Vanuatu to Sāmoa were first occupied 3000 years ago by populations with Lapita pottery at over 100 colonization sites. In Sāmoa, however, the first millennium of settlement is comprised of only a few isolated archaeological sites, and only one with Lapita pottery. This unique archaeological record is typically explained as a result of isostatic subsidence that destroyed or displaced more numerous coastal colonization sites. Three additional hypotheses may account for this pattern. First, few coastal flats may have existed for settlement, limiting occupation of the archipelago. Second, terrestrial geological processes may have destroyed what were once more numerous sites. Third, the few early and isolated sites in Sāmoa may reflect a small population of colonists resulting from demographic processes, including wave-front population density, or the Allee effect. We conducted a preliminary examination of the first two alternative hypotheses through a programme of coring and excavation across three coastlines on ‘Upolu island, Sāmoa. Sub-surface sediment data suggest both hypotheses may be valid explanations in different coastal settings. We propose additional research to test this possibility.

A South Pacific Cyclone-caused GPS Positioning Error and Its Impact on Remote Oceanic Island Communities

Satellite navigation gains importance in sustainable development of modern civilisation. With the increasing number of GNSS-based technology and socio-economic systems and services, satellite navigation has become an essential component of national infrastructure. This calls for novel requirements on GNSS positioning perfomance, and increasing need for resilient GNSS development. Here we examined the impact of rapidly developing tropical cyclone on GPS positioning performance degradation, and the resulting impact on oceanic non-navigation and navigation GPS applications. We presented the methodology for indirect simulation-based GPS positioning performance evaluation through utilisation of experimental GPS observations, GNSS Software- Defined Radio (SDR) receiver, and a statistical analysis and framework we developed in the R environment for scientific computing. We identified alteration of GPS positioning error components time series statistical properties, and discuss the potential impact on GPS-based services essential for remote oceanic island communities. Manuscript concludes with the summary of findings, proposal for recommendations on improved GNSS resilience, and an outline for future research.

Inhabiting Remote Tropical Seashores at 1500–1100 b.c.: Water, Practicalities, and Rituals in the Mariana Islands

ABSTRACTWhen people first inhabited the Remote Oceanic region of the world at 1500 b.c., they generated archaeological sites attesting to their practical coastal adaptations in tandem with their ceremonial traditions, wherein water figured vitally in daily living and ritual performance. Of eight known first-settlement sites in the Mariana Islands, Ritidian in Guam uniquely incorporates one residential habitation plus two caves related to water collection, pictographs, consumption of unusual foods, and use of exceptionally decorative objects. The inter-connected findings clarify what was “special” about the special-use caves, in total articulating a fuller sense of cultural life and landscape than otherwise could be possible.

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.

The lexicon of Proto Oceanic: The culture and environment of ancestral Oceanic society ed by Malcolm Ross, Andrew Pawley, and Meredith Osmond (review)

Reviewed by: The lexicon of Proto Oceanic: The culture and environment of ancestral Oceanic society ed by Malcolm Ross, Andrew Pawley, and Meredith Osmond Paul Geraghty Malcolm Ross, Andrew Pawley, and Meredith Osmond, eds. 2011. The lexicon of Proto Oceanic: The culture and environment of ancestral Oceanic society. vol. 4: Animals. Canberra: Pacific Linguistics 621. xxvi + 576 pp. ISBN 978-085-883626-6. $Aust. 132.00 (Australia), $Aust. 120.00 (International), paper. This volume is the latest in the series resulting from the Australian National University’s monumental undertaking to reconstruct linguistically the society and world of the speakers of Proto-Oceanic (POc), undertaken by the Department of Linguistics, Research School of Pacific and Asian Studies. Of the seven proposed volumes, the first, published in 1998, was on material culture, the second, published in 2003, on the physical environment, and the third, published in 2008, on plants. This volume, entitled Animals, should be understood to cover “animals” in the broadest sense of the term (might “fauna” have been less ambiguous?), including fish, aquatic invertebrates, mammals, reptiles, amphibians, insects, and other terrestrial invertebrates. In addition, there are two chapters by Andrew Pawley on special topics—“Stability and change in Oceanic fish names,” and “Were turtles fish in Proto Oceanic?: Semantic reconstruction and change in some terms for animal categories in Oceanic languages”—and finally two appendices (“Data sources and collation” and “Languages”), a list of references, and three indexes (“Index of reconstructions by proto-language,” “Alphabetical index of reconstructions,” and “Index of English and biological terms”). All chapters are authored by one or more of the editors, except for that on birds, which is by Ross Clark. As we have come to expect from Pacific Linguistics, this is a highly competent piece of work, and an impressive one, too, in many ways, not least in sheer volume—there are over 600 pages, 17 maps, 44 tables, 91 figures (mostly drawings of fish and other natural species), and nearly 500 Proto-Oceanic reconstructions (many more if variants and other levels are considered) based on data from nearly 600 languages (including “dialects”). The work will be useful not only to those interested in the prehistory of the Pacific, and to ichthyologists, zoologists, and ornithologists, but also to linguists looking for data on semantic change, sound change, subgrouping, and so on. Overall, the volume is easy to read and to use, and typographical and other errors are few. Some may quibble about the arrangement of topics, for instance, that whales and bats are included under mammals, when most (perhaps all?) Oceanic languages class them as “fish” and “birds,” respectively. But the authors explain that it is not certain that Oceanic taxonomies agree on these classifications, and, in any case, the typical reader would probably expect to find the “scientifically” based taxonomy being followed. Developments in the field since the earlier volumes have led to some changes. One is the inclusion of two new first-order “subgroups” of Oceanic: the Temotu subgroup (Reef Santa Cruz and Utupua and Vanikoro) and the Southern Oceanic linkage (Vanuatu and New Caledonia). Because of the now even more “rake”-like structure of the higher echelons of the Oceanic subgroup—that is, there being many first-order subgroups—the authors have felt the need to guard against a proliferation of reconstructions based on just two of these first-order subgroups. They have, therefore, proposed two [End Page 524] “phantom” subgroups, Remote Oceanic (Southern Oceanic, Micronesian, and Central Pacific) and Eastern Oceanic (Remote Oceanic plus Southeast Solomonic), for which they admit the evidence is very weak, but which are necessary as “convenient hypotheses that allow us to retain rigorous criteria for a POc reconstruction” (13). Hence the criterion for a reconstruction to be recognized as POc is that reflexes occur in at least two of the following: Admiralties (or Yapese or Mussau), Western Oceanic, Temotu, and “Eastern Oceanic,” and that borrowing is not a possible explanation for its distribution; and also, of course, if reflexes are found both in and beyond Oceania. The authors have not incorporated Blust’s (1998) proposal that Oceanic subgroups at the highest level into Admiralties and non-Admiralties (“Nuclear Oceanic”), but point out...

Paleo‐Terrain Research: Finding the First Settlement Sites of Remote Oceania

A paleo‐terrain approach can situate ancient sites within their original landscape settings, as illustrated in a case study of the Mariana Islands in the western Pacific. This example combines computer‐aided terrain modeling with site‐specific excavations to reconstruct the shapes and configurations of landforms during the period of first human settlement of Remote Oceania, 1500–1000 B.C. The results support new understanding of humanity's first contact with the Remote Oceanic environment. The same approach can be applied in other settings to advance programs of site‐discovery and general studies of ancient site settings and ecology.

Timing and Number of Colonizations but Not Diversification Rates Affect Diversity Patterns in Hemosporidian Lineages on a Remote Oceanic Archipelago

Parasite diversity on remote oceanic archipelagos is determined by the number and timing of colonizations and by in situ diversification rate. In this study, we compare intra-archipelago diversity of two hemosporidian parasite genera, Plasmodium and Leucocytozoon, infecting birds of the Mascarene archipelago. Despite the generally higher vagility of Plasmodium parasites, we report a diversity of Plasmodium cytochrome b haplotypes in the archipelago much lower than that of Leucocytozoon. Using phylogenetic data, we find that this difference in diversity is consistent with differences in the timing and number of colonizations, while rates of diversification do not vary significantly between the two genera. The prominence of immigration history in explaining current diversity patterns highlights the importance of historical contingencies in driving disparate biogeographic patterns in potentially harmful blood parasites infecting island birds.

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.

Topics in Oceanic morphosyntax (review)

Reviewed by: Topics in Oceanic morphosyntax Robert Early Claire Moyse-Faurie and Joachim Sabel, eds. 2011. Topics in Oceanic morphosyntax. Trends in Linguistics, Studies and Monographs 239, vi + 344 pp. Berlin/Boston: De Gruyter Mouton. ISBN 978-3-11-025989-6 (hardbound), e-ISBN 978-3-22-025991-9 (e-book), $140.00 or €99.95 each; or $210.00 or €149.95 for both hardbound and e-book. This volume contains an introduction and nine papers, providing 340 pages of useful advances in the description and analysis of Oceanic languages, prepared by established Oceanic scholars. Each paper has its own bibliography, and the volume as a whole has two pages of subject index and two pages of language index (113 languages or language subgroups are mentioned). Some papers have their own list of abbreviations, others do not. The editors arrange the papers into three topic-based sections: sentential syntax and sentence types; nominal morphosyntax; and historical developments. Some papers cover issues in Oceanic (three papers) and Polynesian (two papers), and others deal with specific Polynesian languages (two papers: Niuean and Tahitian) or other non-Polynesian Oceanic languages (two papers: Unua of Vanuatu [Remote Oceanic, North-Central Vanuatu] and Saliba of Milne Bay, Papua New Guinea [Western Oceanic, Papuan Tip]). The interaction of language with topic is shown in table 1, which includes the author names and titles of all papers. This might appear to be a somewhat sporadic, or at least eclectic, collection, but the papers have come together because they mostly represent the research topics that their authors chose to present at COOL7 (Seventh Conference on Oceanic Linguistics) in Nouméa, New Caledonia in July, 2007, and the title of the collection is probably the best that could be found to provide some kind of overarching unity or schema for the compilation. However, since the publication of formal volumes of conference proceedings seems to have fallen from favor with the organizers of the COOL series, or with publishers, or with university authorities who rank the publication outputs of their academic staff, the editors of this volume are to be thanked for providing an opportunity for these authors to present their papers to a wider audience. The editors are similarly to be congratulated for the comprehensive introduction provided to the volume. All papers are placed in the context of earlier typological overviews and studies of Oceanic languages, and general theoretical frameworks. For each paper, one or two pages of discussion first provides this theoretical and typological orientation, and [End Page 602] then the paper's major claims and findings are summarized. The introduction concludes with a single paragraph summary of each paper ordered by the authors' surnames. Click for larger view View full resolution Table 1. Interaction of Language with Topic There is a slight drawback to the comprehensiveness of the introduction, however, as it results in a certain level of repetitiveness. Each paper's key conclusions are detailed at least four times: first, in the context of the introductory theoretical discussion; second, in the paper summaries given at the end of the introduction; and then again in the introductions and conclusions of the papers themselves. The second of these, the summaries, are probably the authors' own paper abstracts, as suggested by the use of a "we" (15) that escaped being edited out. This organization also results in some apparent contradictions between the editors and the papers they are introducing. For example, Margetts's abstract (15) states that the variation in order of stems (V-N and N-V) found in Saliba noun incorporations is unusual, and "has not been described for other languages of the Papuan Tip cluster or the wider Oceanic language group." However, the editors have already posited a counter to this, by indicating (9) that this possibility "is also attested in Polynesian languages such as Samoan and East Futunan." There are also divergent claims that are reiterated by the editors in the context of discussing different papers, but are not resolved. For example, in the discussion of his own paper, Sabel claims that "Kiribati and Fijian are configurational free word order languages" (5), but on the next page, in discussing another paper, the view that...

The Role of Mesoscale Eddies in the Remote Oceanic Response to Altered Southern Hemisphere Winds

Abstract It has been suggested that a strengthening of the Southern Hemisphere winds would induce a more vigorous overturning through an increased northward Ekman flux, bringing more light waters into the oceanic basins and enhancing the upwelling of North Atlantic Deep Water in the Southern Ocean, thereby increasing ocean ventilation. Simulations from a coarse- and a fine-resolution version of a coupled model, subject to idealized wind stress changes in the Southern Ocean, are presented. In the fine-resolution eddy-permitting model, changes in poleward eddy fluxes largely compensate for the enhanced equatorward Ekman transport in the Southern Ocean. As a consequence, northward transport of light waters, pycnocline depth, Northern Hemisphere overturning, and Southern Ocean upwelling anomalies are much reduced compared with simulations in the coarse-resolution model with parameterized eddies. These results suggest a relatively weak sensitivity of present-day global ocean overturning circulation to the projected strengthening of the Southern Hemisphere winds.

Plant Conservation on a Remote Oceanic Island: The Case of Norfolk Island

Plant Conservation on a Remote Oceanic Island: The Case of Norfolk Island

Final Consonants in Remote Oceanic

This paper examines retention and loss of Proto-Oceanic final consonants in three different groups of Remote Oceanic languages in the light of Blevins's recent discussion in this journal of the unnaturalness of final C-loss within the wider Austronesian family. Languages of (i) northwest Malakula, (ii) southern Vanuatu, and (iii) the Loyalty Islands and northern New Caledonia do not experience the total or near-total loss of final consonants that is commonplace elsewhere within Remote Oceanic. Each group shows partially different patterns of retention and loss from the others, and there are also some differences between members of the same group; but in no case was there a rule deleting all final consonants. There were, however, rules deleting all final vowels, and this V-deletion process may have created a situation in which final consonants were more resistant to loss than in languages with predominantly open final syllables. I will suggest that in each of these three areas consonants were lost by means of natural rules, and that a series of natural rules, rather than a single unnatural rule, may be the explanation for cases in other subgroups where all final consonants have been lost.

Genome-wide distribution of linkage disequilibrium in the population of Palau and its implications for gene flow in Remote Oceania.

Linkage disequilibrium (LD) between alleles on the same human chromosome results from various evolutionary processes and is thus telling about the history of populations. Recently, LD has garnered substantial interest for its value to map and fine-map disease genes. We examine the distribution of LD between short tandem repeat alleles on autosomes and sex chromosomes in the Remote Oceanic population of Palau to evaluate whether the data are consistent with a recent hypothesis about the origins of genetic variation in Palau, specifically that the population experienced extensive male-biased gene flow following initial settlement. Consistent with evolutionary theory based on effective population size, LD between X-linked alleles is stochastically greater than LD between autosomal alleles, however, small but detectable LD occurs for autosomal markers separated by substantial distances. By contrast, while Y-linked alleles experience only one-third the effective population size of X-linked alleles, their mean value for pairwise LD is only slightly larger than X-linked alleles. For a small population known to experience at least two extreme bottlenecks, 56 six-locus Y haplotypes exhibit remarkable diversity (0.96), comparable to Y diversity of Europeans, however, autosomal and X-linked markers display significantly less diversity, as measured by heterozygosity (4.1% less). Palauan Y haplotypes also fall into distinct clusters, again unlike that of Europe. We argue these data are consistent with waves of male-biased gene flow.

Trade Wind Rainfall near the Windward Coast of Hawaii: Corrected Data Yield Improved Results

This note documents the effects of a radar calibration error that affected 5% of the data used in an earlier study by Carbone et al. While the original intent of this correction was merely to set the record straight, a significant finding emerged from the revised time series. The main impact is to reveal a more rapid spatial decorrelation between island Froude number (Fr) and oceanic rainfall, a measure of the dynamical blocking effects upstream of Hawaii. There no longer exists a residual correlation between Fr and cumulative rainfall over the remote ocean, defined in this instance as distances >50 km from shore. This result both simplifies and strengthens the conclusions of the original work, which was based on a very short time series. The strong dependence of rainfall on Fr over the coastal lowlands and near shore remains unchanged from the results presented by Carbone et al. To the extent that remote oceanic rainfall is expected to be uncorrelated with Fr, there is increased confidence with respect to the causes and effects of island blocking on rainfall production over and near the island.

Sources and sinks of oceanic hydrogen sulfide – an overview

In recent years hydrogen sulfide (H 2S) has played a decreasing role in the global sulfur budget, and is discussed today primarily in terms of local impacts. This discussion focuses on two of the remaining global issues, namely the atmospheric concentration of H 2S over the remote ocean and the flux of H 2S between the ocean and the atmosphere. Available information on the measurements of H 2S in the remote oceanic atmosphere is evaluated through consideration of previous data and analytical methods. Production and loss of H 2S in the ocean is discussed, and potential sources and sinks of any H 2S over the open ocean briefly reviewed, the issue of the oceanic contribution of H 2S to the remote oceanic atmosphere is then addressed. Based on the concentrations reported for H 2S in the remote marine atmosphere, consideration of the analytical technique used to measure the H 2S, and the potential oceanic sources of H 2S, it is concluded that there is little evidence for any H 2S in the remote marine atmosphere being of marine origin.

Mitochondrial and Nuclear Genetic Relationships among Pacific Island and Asian Populations

Mitochondrial and autosomal short tandem-repeat (STR) genetic distances among 28 Pacific Island and Asian populations are significantly correlated (r=.25, P<.01) but describe distinct patterns of relationships. Maternally inherited-mtDNA data suggest that Remote Oceanic Islanders originated in island Southeast Asia. In contrast, biparental STR data reveal substantial genetic affinities between Remote Oceanic Islanders and Near Oceanic populations from highland Papua New Guinea and Australia. The low correlation between maternal and biparental genetic markers from the same individuals may reflect differences in genome-effective population sizes or in sex-biased gene flow. To explore these possibilities, we have examined genetic diversity, gene flow, and correlations among genetic, linguistic, and geographic distances within four sets of populations representing potential geographic and cultural spheres of interaction. GST estimates (a measure of genetic differentiation inversely proportional to gene flow) from mtDNA sequences vary between 0.13 and 0.39 and are typically five times greater than GST estimates from STR loci (0.05-0.08). Significant correlations (r>.5, P<.05) between maternal genetic and linguistic distances are coincident with high mtDNA GST estimates (>0.38). Thus, genetic and linguistic distances may coevolve, and their correspondence may be preserved under conditions of genetic isolation. A significant correlation (r=.65, P<.01) between biparental genetic and geographic distances is coincident with a low STR GST estimate (0.05), indicating that isolation by distance is observed under conditions of high nuclear-gene flow. These results are consistent with an initial settlement of Remote Oceania from island Southeast Asia and with extensive postcolonization male-biased gene flow with Near Oceania.