In over two decades of exploring the mesopelagic waters of Monterey Bay, CA, remarkably few Bathochor- daeus charon (n = 15) were observed, while thousands of B. stygius have been encountered. Both species occupy a similar depth range in Monterey Bay, yet, based on the large differences in COI they are clearly not interbreed- ing populations. Moving forward we intend to look more closely at the diversity of larvaceans in the mesopelagic habitat, identifying these important organisms respon- sible for vertical transport of carbon through the water column. As of 2009, the recognized number of appendicu- larian species was 70, of which 43 are described for the Pa- cific Ocean (Fenaux et al. 1998; Castellanos et al. 2009), Bathochordaeus charon unequivocally among them.
Shipping emissions have been previously noted as major contributors to aerosol and cloud properties in the N.E. Pacific environment (Murphy et al., 2009; Lack et al., 2011; Coggon et al., 2012; Cappa et al., 2014). Coggon et al. (2012) demonstrated that 70% of cloud residual particles measured in the California shipping lanes were impacted by nearby shipping emissions. Available compositional data further suggests that shipping emissions could be expected to produce Aitken mode hygroscopicities observed during RF4 and RF5. For instance, Lack et al. (2011) observed an effective kappa parameter of 0.68-0.73 from exhaust produced by a large (96,500 ton) container vessel, while the smaller Research Vessel Atlantis sampled during the same study produced a value of ~0.2. Hygroscopic growth factor measurements of shipping exhaust emitted by another large (90,000 ton) container vessel by Murphy et al. (2009) suggest an effective κ = 0.1-0.5.
Overall, our results indicate that species with large ranges (.1000 km) dominate the fauna of Davidson Seamount (Fig. 4). Seventy-nine percent of observed species have ranges that extend at least 1000 km from Davidson with 50% of the fauna greater than 1800 km. Several species have ranges that extend from the Gulf of California to the NortheastPacificOcean off Canada, the extent of the California current. A major break in the probability distribution (Fig. 4) occurs at this spatial scale (,1500 km). It is important to note, however, that our dataset relies heavily on MBARI research efforts concentrated in this area. Another sudden shift occurs around 3500–4500 km, the distance from Davidson to Hawaii, and the furthest western extent of MBARI’s sampling. The break at 8500 km represents records extending to the Northwest Pacific, possibly indicating a ‘Ring of Fire’’ Pacific distribution. A small minority of this group also includes species found in the Atlantic Ocean with greater geographic ranges, an artifact of the conservative linear approach we utilize (see methods). Amazingly ,10% of the fauna at Davidson have ranges greater than 13000 km extending into either the Antarctic or Indian Oceans. Taxonomically, the largest faunal components of Davidson, the cnidarians (typically, deep-sea corals), poriferans, and echinoderms, account for the majority of the smaller ranges. Those species with ranges less than 500 km include the 12 unresolved species mentioned above. The remaining species are those with ranges spanning a minimum distance from Davidson Seamount to Monterey Canyon and often to nearby seamounts such as Rodriguez and Pioneer.
The model yields satisfactory outputs because it is able to detect the attraction and counter- clockwise rotation of the cyclonic vortexes forming the binary systems, which modifies the typical northwestward trajectory of the main storm, including if the vortexes merger occurs or not. In both cases, either the resulting cyclone or the cyclonic vortex that was initially located eastward off the binary system usually penetrates into the continent, and tends to move parallel to the coast, or with the eye over the continent or over the ocean. This result is illustrated by the tropical storm Alma.
have flourished since the 1970s, with growth in wild populations augmented by rising hatchery production. As their abundance has grown, so too has evidence that they are having important effects on other species and on ocean ecosystems. In alternating years of high abundance, they can initiate pelagic trophic cascades in the northern North PacificOcean and Bering Sea and depress the avail- ability of common prey resources of other species of salmon, res- ident seabirds, and other pelagic species. We now propose that the geographic scale of ecosystem disservices of pink salmon is far greater due to a 15,000-kilometer transhemispheric teleconnection in a PacificOcean macrosystem maintained by short-tailed shearwa- ters (Ardenna tenuirostris), seabirds that migrate annually between their nesting grounds in the South PacificOcean and wintering grounds in the North PacificOcean. Over this century, the frequency and magnitude of mass mortalities of shearwaters as they arrive in Australia, and their abundance and productivity, have been related to the abundance of pink salmon. This has influenced human social, economic, and cultural traditions there, and has the potential to alter the role shearwaters play in insular terrestrial ecology. We can view the unique biennial pulses of pink salmon as a large, rep- licated, natural experiment that offers basin-scale opportunities to better learn how these ecosystems function. By exploring trophic interaction chains driven by pink salmon, we may achieve a deeper conservation conscientiousness for these northern open oceans.
1.2. Mean Sea Level (MSL) Trends
Globally averaged sea level rise is 11.7 6 0.2 mm yr 21 as estimated from coastal and island tide gauge meas- urements from 1900 to 2009 (Church & White, 2006, 2011; Nicholls & Cazenave, 2010), and 13.4 6 0.4 mm yr 21 for 1993–2016 as estimated from satellite altimetry (http://sealevel.colorado.edu/; Nerem et al., 2010). The estimates of MSL rise before the satellite era are based on spatially sparse tide gauge records, and improved methods of estimating the pre-1990 rise suggest a lower historical rate of 1.1 6 0.3 mm yr 21 (Dan- gendorf et al., 2017). A semiempirical estimate of sea level rise over the past 3,000 years suggests that the 20th century has shown the fastest increase in MSL over the last three millenia (Kopp et al., 2016), and that without global warming, the observed increases in global sea levels would have been much less. Furthermore, since 1970, global mean sea level rise has been dominated by anthropogenic forcing (Slangen et al., 2016). Due to the combined effects of spatially variable wind and warming, and different vertical rates of land sub- sidence, MSL rise is not spatially uniform (e.g., Kopp et al., 2014; Merriﬁeld et al., 2009). In the Southwestern Paciﬁc, MSL rates of 110 mm yr 21 or greater were observed for 1993–2009 (Merriﬁeld, 2011), while MSL rise in the Northeast Paciﬁc was below the global average over the same period. The anomalously rapid sea level rise in the western Paciﬁc is underestimated in most models, likely due to a low variability in tropical zonal wind stress (Peyser & Yin, 2017). However, the extreme rate in the Western tropical Paciﬁc is unlikely to persist unabated (Bromirski et al., 2011). The El Ni~ no/Southern Oscillation (ENSO) is a strong contributing factor to sea surface anomalies in the Paciﬁc (Collins et al., 2010; K€ ohl et al., 2007). Local, short-term MSL anomalies associated with ENSO are often much larger than long-term trends in MSL rates (Merriﬁeld et al., 2009), and major events (e.g., 1997–1998) give rise to widespread MSL ﬂuctuations, with yearly averaged MSL rises or falls of 200 mm or more (Nerem et al., 1999). ENSO related sea level variability is difﬁcult to remove entirely from MSL time series, due to its quasi-periodic behavior, and large geographical extent that the signal affects (Hamlington, et al. 2011). A recent increase in upper-ocean warming may also be leading to an increased decadal sea level rise (Domingues et al., 2008). Lastly, on a seasonal time scale, regions affected by the monsoon may exhibit strong monthly MSL variability due to rainfall and wind patterns (Wyrtki, 1961).
Sumatra in the eastern equatorial Indian Ocean and the minimum is close to 0 mm yr − 1 just south of the equator in the central Indian Ocean. In the Pacific, the major large-scale features are a maximum in the rate of sea-level rise in a tongue-like feature in the north-eastern Pacific and a minimum along the Equator and in the western equatorial PacificOcean (particularly east of Papua New Guinea). Also shown on Fig. 6 are the trends from the 9 longest island tide-gauge records over the period 1950 to 2001. These gauges are in general agreement with the recon- struction but stronger confirmation of the patterns is not possible with the available in situ data. The gradient in sea- level rise (low in the north-west and high in the south-east) along the Hawaiian island chain (21°N, 157°W) is confirmed from the estimates of ocean steric sea-level trends and tide- gauge records corrected for gross vertical motion due to volcanism estimated using GPS data ( Caccamise et al., 2005 ). Lombard et al. (2005) show two estimates of ocean steric height trends. Both of these estimates have a tongue
We routinely see these kinds of explosions-- irruptions--when rats enjoy an abun- dance of resources. At a latitude similar to Rapa Nui, but with a lower abundance of food resources, Kure Atoll (28°24°N) in the northwest Hawaiian Islands supports Polynesian rat densities averaging 45 per acre, with maximum recorded densities reaching 75 (Wirtz 1972). At a minimal estimate of only 45 rats per acre, Rapa Nui would have had a rat population over 1.9 million. At 75 per acre, a reasonable density given the palm nuts and other forest resources, the rat population of Rapa Nui could have reached more than 3.1 million. Such documented population growth rates and rat densities on Pacific islands suggest that Rapa Nui could have easily supported a huge number of rats soon after people first arrived. An initial peak rat popula- tion would be sustained until resources diminished and rat numbers fell, following a boom and bust pattern typical of invasive species.
The Herring Bay rhodolith bed has sand as the under- lying substratum, much of which is covered by rhodoliths and shell fragments. When percent cover was visually estimated in eighteen 0.25 m 2 quadrats per transect (along three random transects ranging from 12 m to 18 m), only 29.4%"9.6% (mean"SE) of the substratum was sand, while 52.8%"9.8% (mean"SE) and 17.8%" 8.0% (mean"SE) was covered by rhodoliths and shell fragments, respectively. Rhodoliths were significantly more abundant than shell fragments, but not sand (ANO- VA, arcsin transformed, F 2,51 s 3.029, ps0.05, post-hoc Fisher’s PLSD, pF0.01). All rhodoliths were collected from the surveyed quadrats. Densities of rhodoliths aver- aged 27.5"8.7 (mean"SE) individuals/0.25 m 2 and bio- mass averaged 29.7"6.0 g/0.25 m 2 (mean"SE). In addition, fleshy macroalgal cover was noted within each quadrat surveyed. Two brown algae, Agarum clathratum Dumortier and Laminaria saccharina (Linnaeus) J.V. Lamouroux were found in 50% of the surveyed quadrats. This is similar to beds in the temperate Atlantic Ocean (Freiwald et al. 1991), but different from the Gulf of Cal- ifornia where red algae dominate (Steller et al. 2003). In general, this high algal cover is similar to other beds in Brazil and the Gulf of California (Steller et al. 2003).
4 Marine Radionuclide Research Center, Korea Institute of Ocean Science and Technology, Ansan, South Korea, 5 School of
Oceanography, University of Washington, Seattle, Washington, USA, 6 State Key laboratory of Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS), Wuhan University, Wuhan, China
Abstract Oceanic dimethyl sul ﬁde (DMS) is of interest due to its critical inﬂuence on atmospheric sulfur compounds in the marine atmosphere and its hypothesized signi ﬁcant role in global climate. High-resolution shipboard underway measurements of surface seawater DMS and the partial pressure of carbon dioxide (pCO 2 ) were conducted in the Atlantic Ocean and Indian Ocean sectors of the Southern
brochure put it, while the cruise itinerary would prioritise the interests of tourists, not traders. 11
Cruising was also deemed superior because it encompassed ports that ordinarily lay outside of the Union Company’s existing transport network. In 1884, only Fiji, a British crown colony annexed in 1874, was already linked to Auckland by a monthly passenger and cargo service. Tonga and Samoa, both under direct British political influence but outside of its formal empire, could only be reached by “stray sailing vessels”. 12 The cruise, in linking the three island groups, confirmed the power of steam to “unlock” the region and associated the tour with the prestige of unrivalled and exclusive access. Furthermore, the multi-stop itineraries of later cruises were perceived to offer a “comprehensive” or “complete” idea of the Pacific, enabling passengers to see “all that was worth seeing”. 13 In contrast to the “beach crossings” of previous generations, an important metaphor in Pacific contact history, shipping companies might be understood, as Ewan Johnston suggests, as having “crossed cultures” on tourists’ behalf. 14
Tropical cyclones (TCs) are among the most devastating and destruc- tive natural hazards on Earth ( 1, 2), with the most intense TCs found over the northwestern Pacific. Super Typhoon Haiyan of 2013, one of the strongest TCs in history over the northwestern Pacific, caused more than 6200 deaths with additional 1785 people reported missing in the Philippines alone ( 3). In theory, a potential intensity (PI) exists and can be predicted with a given sea surface temperature (SST) and atmospheric thermodynamic profile ( 4, 5). Unfortunately, the intensi- ty of individual TCs is extremely difficult to predict in reality ( 6) be- cause of various internal and environmental factors involved in the evolution of TC intensity ( 7, 8), such as vertical shear of horizontal winds in the troposphere ( 9) and interaction of the TC with the ocean ( 8, 10–14). The challenge extends to and becomes even bigger for pre- diction and projection of TC intensity on time scales beyond a season ( 15). Adding to the challenge is the fact that the climate models in use do not have sufficient spatial resolution to adequately resolve TC struc- ture and intensity, although some of them are skillful in reproducing year-to-year changes in seasonal TC counts and track density ( 16–18). The projected changes in TC intensity under global warming vary widely among models with large and poorly quantified uncertainties ( 19). Alternatively, a statistical approach that links the seasonal mean TC intensity to climate indices can be very helpful both for the pro- jections and as a guide to understanding the relevant factors that govern mean TC activity. Here, we disentangle the causes of the interannual-to-decadal variability of the lifetime peak TC intensity in the northwestern Pacific where TCs are most active. We restrict our attention to TCs that reach at least typhoon intensity (equivalent to category 1 hurricane intensity in the North Atlantic). We focus on the year-to-year variability of the seasonal mean lifetime peak intensity (obtained from the lifetime peak intensity of all TCs over the entire typhoon season for each year; see Materials and Methods) instead of the variability among individual TCs because the dominant factors for the latter vary from case to case.
Seamounts are undersea mountains over that occur in all ocean basins but few of which have been sampled for their marine biota (Hall-Spencer et al. 2011). They rise steeply from the abyssal plain and may ascend to shallow depths within the photic zone and create suitable habitat for benthic algae. It has been suggested that seamounts may function as stepping stones for the transoceanic dispersal of benthic species and may also host endemic species. How- ever, a recent review using mainly faunistic data (Rowden et al. 2010) drew attention to gaps in our knowledge of seamount biodiversity and ecology and questioned hith- erto-held views on seamounts as unique and fragile envi- ronments, and hot spots of biodiversity and endemicity.
inclination from the west to the northwest direction, and third, between 52 and 56 ◦ S, the wind blew along the austral coast of the Magellan region, while in the rest of the study area, the wind direction was perpendicular to the coast. The surface-wind average registered as a meridional gradient, in which low speeds (5–6 m s −1 ) were observed in the north- ern domain, and stronger winds (10–2 m s −1 ) were registered closer to 51 ◦ S. The standard deviations were similar between the satellite products ( ± 3.0 to ± 4.2 m s −1 ), representing the same meridional gradient observed in the surface-wind mag- nitude, but the ASCAT data registered a lower variability and less intense surface-wind magnitudes, compared with the data obtained by QuikSCAT (Fig. 2a and b). Nevertheless, lower standard deviations and wind magnitudes were ob- tained by the ERA5 reanalysis data (Fig. 2c). Computations of the seasonal cycle, using all data sets (e.g., QuikSCAT, ASCAT, and ERA5), showed a similar meridional gradient to that obtained in the average analysis, highlighting the time persistence and high intensity of the northwesterly winds in the open ocean water of the Magellan region (51 to 56 ◦ S).
The major focus of this study is to explore the mechanisms governing remote ocean in ﬂuence on variability of the WAM on the interannual timescale. We emphasize the role of ENSO forcing in the hydro- logical balance, i.e., the moisture ﬂux convergence pattern over the Sahel and the resulting precipitation ﬂuctuations. By decomposing the moisture budget into contributions from speciﬁc humidity advection, circulation changes that affect mass convergence, and changes in moisture transport convergence by subseasonal eddies, we can identify the primary process(es) that govern the change in net surface moisture ﬂux (precipitation-evaporation or P-E) [Seager et al., 2010]. The utility of such a diagnostic approach has been demonstrated for observed precipitation variability in the Southeastern U.S. [Li et al., 2013], future projections of midlatitude hydroclimate [Seager et al., 2010], as well as for the WAM annual cycle [Fontaine et al., 2003; Thorncroft et al., 2011]. More recently, we investigated the case of the 20th century “decadal shift” in Sahel rainfall [Pomposi et al., 2014], and here we employ a similar approach to study the changes in mechanisms of moisture convergence on the interannual timescale, addressing the following:
Massana et al., 2015 ; de Vargas et al., 2015 ) and our results also revealed
the different diversity and structure of microeukaryotes among the three regions ( Fig. 2 , Table 2 ). Metazoa and Dion ﬂagellate were the most abundant eukaryotic groups in our study, which was consistent with a previous study on global ocean scale ( de Vargas et al., 2015 ). Al- though we used a 200 μm sieve to remove large zooplankton, Metazoa still accounted for most sequence reads of all microeukaryotes and par- ticularly dominated in the MWR. A previous study shows that elongated species of small-size and eggs, spores or larvae of large-size zooplankton can pass through the 200 μm pores and contribute to the assemblage