Journal articles on the topic 'Marine accidents – California – Santa Barbara'

The water on deck caused on a restrained ship model without forward speed in head waves is studied experimentally by using a transient test technique. A single water-shipping event is induced by the wave packet, and the severity of the interaction is controlled by the wave-packet steepness. Three different bow geometries are considered. Two of them are analytical hull forms, and the last is the ESSO-Osaka tanker. The models are equipped with a transparent-material deck to study the flow-field evolution by image analysis. A vertical wall is placed at a certain distance from the forward perpendicular to mimic the presence of deck structures. Velocity of the shipped water along the deck, pressure field on the deck, and horizontal impact force on the wall are measured. The main fluid-dynamic aspects of the green-water phenomenon are highlighted. For the tested cases, water shipping starts always with the free surface exceeding the freeboard, plunging onto the deck, and forming complex cavities entrapping air inside. The geometry of the air cavity depends on the hull form and the wave steepness. Then the water propagates along the deck. In general, the water front is strongly three dimensional because of the water entering along the deck contour. The interaction of the shipped water with the vertical structure consists of impact, run up-run down cycle, and backward plunging of the water onto the deck, still wetted. The evolution of the pressure field follows that of the water front. Pressure peaks are associated with the impact against the vertical wall, and by the backward plunging of the water on the deck, at the end of the run up-run down cycle of the water. It is shown that both these stages can be of importance from the structural point of view. I am sad to report that Maurizio Landrini was killed in a motorcycle accident on June 26, 2003. Maurizio was an outstanding marine hydrodynamist who had been selected as the 2003 Georg Weinblum Lecturer. He was born on March 2, 1963, and earned his Ph.D. degree in Theoretical and Applied Mechanics at the University of Rome. Except for short periods as a visiting researcher at the Ocean Engineering Laboratory, University of California, Santa Barbara, and the Department of Marine Technology, Norwegian University of Science and Technology, he worked his entire career at INSEAN, the Italian Ship Model Basin. He has authored or coauthored over 80 papers. He was a personal friend and innovative researcher with whom I have spent many hours discussing hydrodynamics. He will be greatly missed in the marine hydrodynamics community. Robert F. Beck

Abstract A summer wind speed maximum extending more than 200 km occurs over water around Point Conception, California, the most extreme bend along the U.S. West Coast. The following several causes were investigated for this wind speed maximum: 1) synoptic conditions, 2) marine layer hydraulic flow effects, 3) diurnal variations, 4) mountain leeside downslope flow, 5) sea surface temperature structure, and 6) island influence. Synoptic conditions set the general wind speed around Point Conception, and these winds are classified as strong, moderate, or weak. The strong wind condition extends about Point Conception, reaching well offshore toward the southwest, and the highest speeds are within 20 km to the south. Moderate wind cases do not extend as far offshore, and they have a moderate maximum wind speed that occurs over a smaller area in the western mouth of the Santa Barbara Channel. The weak wind speed case consists of light and variable winds about Point Conception. Each category occurs about one-third of the time. Atmospheric marine layer hydraulic dynamics dominate the situation after the synoptic condition is set. This includes an expansion fan on the south side of the point and a compression bulge on the north side. The expansion fan significantly increases the wind speeds over a large area that extends to the southwest, south, and east of Point Conception, and the maximum wind speed is increased for the strong and moderate synoptic cases as well. The horizontal sea surface temperature pattern contributes to the sea surface wind maximum through the Froude number, which links the potential temperature difference between the sea surface temperature and the capping inversion temperature with marine layer acceleration in an expansion fan. A greater potential temperature difference across the top of the marine layer also causes more energy to be trapped in the marine layer, instead of escaping upward. The thermally driven flow resulting from differential heating over land in the greater Los Angeles, California, coastal and elevated area to the east is not directly related to the wind speed maximum, either in the Santa Barbara Channel or in the open ocean extending farther offshore. The effects of the thermally driven flow extend only to the east of the Santa Barbara Channel. The downslope flow on the south side of the Santa Ynez Mountains that is generated by winds crossing the Santa Ynez Mountain ridge contributes neither to the high-speed wind maximum in the Santa Barbara channel nor to that extending farther offshore. Fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) simulations do support a weak leeside flow in the upper portions of the Santa Ynez Mountains. The larger Channel Islands have a significant effect on the marine layer flow and the overwater wind structure. One major effect of the Santa Barbara Channel Islands is the extension of the zone of high-speed winds farther to the south than would otherwise be the case.

AbstractAs part of the Precision Atmospheric Marine Boundary Layer Experiment, the University of Wyoming King Air sampled an atmospheric environment conducive to the formation of a hydraulic jump on 24 May 2012 off the coast of California. Strong, northwesterly flow rounded the Point Arguello–Point Conception complex and encountered the remnants of an eddy circulation in the Santa Barbara Channel. The aircraft flew an east–west vertical sawtooth pattern that captured a sharp thinning of the marine boundary layer and the downstream development of a hydraulic jump. In situ observations show a dramatic rise in isentropes and a coincident sudden decrease in wind speeds. Imagery from the Wyoming Cloud Lidar clearly depicts the jump feature via copolarization and depolarization returns. Estimations of MBL depth are used to calculate the upstream Froude number from hydraulic theory. Simulations using the Weather Research and Forecasting Model produced results in agreement with the observations. The innermost domain uses a 900-m horizontal grid spacing and encompasses the transition from supercritical to subcritical flow south of Point Conception. Upstream Froude number estimations from the model compare well to observations. A strongly divergent wind field, consistent with expansion fan dynamics, is present upwind of the hydraulic jump. The model accurately resolves details of the marine boundary layer collapse into the jump. Results from large-eddy simulations show a large increase in the turbulent kinetic energy field coincident with the hydraulic jump.

The California Department of Fish and Wildlife (CDFW) uses fiberglass material for forensic analysis of oil sheens, while the United States Coast Guard (USCG) method uses a tetrafluoroetheylene-fluorocarbon (TFE-fluorocarbon) polymer net. We performed a field trial of these two materials by sampling natural oil seeps, two in Santa Monica Bay, and three sheen areas in the Santa Barbara Channel. Though the fiberglass material did collect less mass on some trials, the forensic chemistry results demonstrated that both materials were satisfactory for purposes of chemical forensic analysis as each pair of the sampling materials yielded results that were consistent with a common oil seep source.

The marine red alga Sciadophycus stellatus E.Y.Dawson (1945) (Figure 1) was described from specimens dredged at 40–50 meters from the Kellett Channel, south shore of Cerros Island (also known as Cedros Island), Baja California, Mexico (Dawson 1945). This uncommon subtidal species occurs in southern California, Baja California, Mexico and Isla Floreana, Galapagos Islands (as Fauchea rhizophylla Taylor) (Dawson 1945, Abbott and Hollenberg 1976, Millar 2001, Aguilar-Rosas et al. 2010). In California, S. stellatus has been collected in San Diego County (UC2003699) and Palos Verdes Peninsula, Los Angeles County (UC1882843), on the mainland coast of southern California and, more commonly, offshore from Santa Catalina (UC1471598), Santa Barbara (UC2034301), Anacapa (WTU-A-012879) and Santa Cruz Islands (UC1965240). In Mexico, in addition to the type locality, it has been collected from Isla Los Coronados (UC1574390), La Bufadora (Aguilar-Rosas et al. 2010), Isla Natividad (UC1882846), Punta Eugenia (US13095) and Bahia Tortugas (US42090), Baja California (distribution records, unless otherwise cited, are based on specimens in herbaria at the University of California at Berkeley [UC], University of Washington [WTU-A], and the Smithsonian Institution [US]).

Abstract Typical spring and summer conditions offshore of California consist of strong northerly low-level wind contained within the cool, well-mixed marine boundary layer (MBL) that is separated from the warm and dry free troposphere by a sharp temperature inversion. This system is often represented by two layers constrained by a lateral boundary. Aircraft measurements near Point Conception, California, on 3 June 2012 during the Precision Atmospheric MBL Experiment (PreAMBLE) captured small-scale features associated with northerly flow approaching the point with the added complexity of encountering opposing wind in the Santa Barbara Channel. An extremely sharp cloud edge extends south-southwest of Point Conception and the flight strategy consisted of a spoke pattern to map the features across the cloud edge. Lidar and in situ measurements reveal a nearly vertical jump in the MBL from 500 to 100 m close to the coast and a sharp edge at least 70 km away from the coast. In this case, it is hypothesized that it is not solely hydraulic features responsible for the jump, but the opposing flow in the Santa Barbara Channel is a major factor modifying the flow. Just southeast of Point Conception are three distinct layers: a shallow, cold layer near the surface with northwesterly winds associated with an abrupt decrease in MBL height from the north that thins eastward into the Santa Barbara Channel; a cool middle layer with easterly wind whose top slopes upward to the east; and the warm and dry free troposphere above.

This study investigates the influence of planetary boundary layer (PBL) schemes and land surface models (LSMs) on the performance of the Weather Research & Forecasting model in simulating the development of downslope windstorms in the lee of the Santa Ynez Mountains in Santa Barbara, California (known as Sundowner winds). Using surface stations, a vertical wind profiler, and a multi-physics ensemble approach, we found that most of the wind speed biases are controlled by the roughness length z 0 , and so by the choice of LSM. While timing characteristics of Sundowners are insensitive to both LSM and PBL schemes, a clear sensitivity in the horizontal extent of strong surface winds is found for both PBL parameterization and z 0 , which are related to patterns of self-induced wave-breaking near the mountaintop, and the erosion of the marine layer. These results suggest that LSMs with relatively high values of z 0 , and TKE-based or hybrid PBL schemes adequately simulate downslope windstorms in the lee of mountain ranges, specifically in areas where downslope windstorms interact with the marine boundary layer with stably stratified characteristics.

The study of ecosystem services (ES) is becoming increasingly popular, as it plays an important role in human wellbeing, economic growth, and livelihoods. The primary goal of this research is to investigate the global trend in ES research using a rigorous systematic review of highly cited articles. The articles for this study were extracted from Science Citation Index Expanded (SCI-E), Emerging Sources Citation Index (ESCI), and Social Sciences Citation Index (SSCI) databases of Web of Science Core Collection (WoSCC) covering the period from 2000 to 2020. This study was limited to SCI-E, ESCI, and SSCI databases of the Web of Science. The term “ecosystem service/s” has been used as a research term to filter the study sample and eliminate other databases from the analysis. A citation level equal to or greater than 200 was used to further filtration of articles. This query could restrict to 128 articles that are highly cited in the selected period. Bibliometric analysis results show that, according to the author’s keywords, the “ecosystem service/s” keyword is highly connected to the “biodiversity”, “valuation”, “marine spatial planning”, and “conservation planning”. The U.S.A., Canada, China, France, and Australia are the leading countries in the cumulative number of highly cited articles and networks of co-authors. The U.S.A. is a strong contributor to ES research with China, Canada, and France. The most productive universities linked to the United States were the University of Minnesota, the University of California-Santa Barbara (UC Santa Barbara), and the Chinese Academy of Science. The most significant and compelling author is Halpern S Benjamin, who represents UC Santa Barbara. He has earned international recognition for a model he developed to analyze global data sets of anthropogenic drivers of ecological change in marine environments. The most accessed and studied fields in the ES are terrestrial, urban, and marine environments.

Prehistoric marine mammal hunting is of interest to archaeologists worldwide because these animals were exploited by a wide range of coastal societies. Sorting out the roles of particular groups of fauna in prehistoric economies requires detailed attention to the analysis of the entire faunal assemblage. Although marine mammals typically provided large quantities of fat and protein and were desirable prey, they were not always central to the diets of the groups that exploited them, particularly in temperate zones. To evaluate effectively the importance of marine mammal exploitation, scholars should calculate the relative contribution of these animals to the economy, identify changes in hunting techniques, determine the relationship between fauna and other aspects of society, assess changing environmental conditions, and consider alternate explanations for those relationships. A large body of research on the northern Channel Islands of California demonstrates that fishing was relatively more important than marine mammal exploitation in subsistence and in stimulating sociopolitical and technological developments. Recent attempts to credit marine mammal hunting as a driving force in the invention of the plank canoe and the evolution of a chiefdom in the Santa Barbara Channel area misunderstand environmental factors and site histories in this region. Rather than assuming that a pan-Pacific Coast set of traditions existed to exploit these taxa, we see evidence of local and regional differences rooted in variable cultural settings, physiographic and oceanographic conditions, and available technologies. Data from the Santa Barbara Channel are used to explore the relationships among marine mammal use, sociological change, and environmental change.

Ichthyoplankton studies can be used to assess the abundance, distribution, and reproductive activity of marine fishes, but few studies have monitored spawning activity at inshore sites. This study utilized weekly plankton sampling to construct a year-long time series of fish spawning at 6 pier sites along the California coast—Santa Cruz, San Luis Obispo, Santa Barbara, Santa Monica, Newport Beach, and La Jolla; sampling at the La Jolla site continues ongoing monitoring initiated in 2012. Fish eggs were sorted from the collected plankton and identified to species level using DNA barcoding of the COI and 16S genes. While only one year of data has been collected from 5 of the sites, the 2 sites north of Point Conception show markedly reduced diversity compared to the southern sites. Although the species observed reflect the local environment of each site, this pattern of reduced diversity at the northern sites is consistent with the well-documented decline in species richness with latitude along the California coast. The 7-year time series from La Jolla has revealed that spawning activity varies greatly among years, both in terms of egg production and species diversity, with a continuing trend of highest egg numbers in years with colder average winter sea surface temperature.

Abstract Summertime low-level winds over the ocean adjacent to the California coast are typically from the north, roughly parallel to the coastline. Past Point Conception the flow often turns eastward, thereby generating cyclonic vorticity in the California Bight. Clouds are frequently present when the cyclonic motion is well developed and at such times the circulation is referred to as a Catalina eddy. Onshore flow south of the California Bight associated with the eddy circulation can result in a thickening of the low-level marine stratus adjacent to the coast. During nighttime hours the marine stratus typically expands over a larger area and moves northward along the coast with the cyclonic circulation. A Catalina eddy was captured during the Precision Atmospheric Marine Boundary Layer Experiment in June of 2012. Measurements were made of the cloud structure in the marine layer and the horizontal pressure field associated with the cyclonic circulation using the University of Wyoming King Air research aircraft. Airborne measurements show that the coastal mountains to the south of Los Angeles block the flow, resulting in enhanced marine stratus heights and a local pressure maximum near the coast. The horizontal pressure field also supports a south–north movement of marine stratus. Little evidence of leeside troughing south of Santa Barbara, California, was observed for this case, implying that the horizontal pressure field is forced primarily through topographic blocking by the coastal terrain south of Los Angeles, California, and the ambient large-scale circulation associated with the mean flow.

AbstractDetrital terrestrial sediments preserved in near-shore marine basins bear distinctive geochemical identifiers that can be used to identify the on-shore sediment sources and sediment routing through time. Santa Barbara Basin (SBB), offshore of southern California, USA, contains a well-known, continuous, high-resolution Holocene flood record that can provide insights into the frequency and changes in on-shore sources across time for such events. Here SBB-adjacent stream bed sediments are characterized using mineralogical, elemental, and radiogenic strontium and neodymium isotopic compositions. Modern and Holocene SBB flood deposits and Last Glacial Maximum (LGM) sediments were similarly analyzed. The Southern Slopes of the Santa Ynez Mountains and Topatopa Mountains account for ∼85% of SBB Holocene flood deposit sediments, as calculated from Sr-Nd isotope mixing models. During the LGM sea level low stand, the Southern Slopes contribution increased (to ≥90%), while relative sediment contribution from Santa Clara River diminished. This loss was likely compensated, however, by increased sediment flux from the Southern Slopes and the Channel Islands.

The neogastropod family Columbellidae is a diverse cosmopolitan group of small marine snails, with its greatest diversity in the tropics. They are represented in high latitudes, but the columbellid fauna of higher latitudes tends to be much less well documented. The present paper documents the nearshore columbellid fauna of the northeastern Pacific Ocean, from the Aleutian Islands to Cedros Island, near the dividing point between Baja California and Baja California Sur. It is based on work by J.H. McLean, and completed posthumously. Examination of the regional columbellid collections in the Natural History Museum of Los Angeles County and the Santa Barbara Museum of Natural History has resulted in 24 species in eight genera, of which four new species and one new genus are described herein. The present paper focuses on dry shell material.

We provide detailed contextual information on 25 14C dates for unusually well-preserved archaeological and paleontological remains from Daisy Cave. Paleontological materials, including faunal and floral remains, have been recovered from deposits spanning roughly the past 16,000 yr, while archaeological materials date back to ca. 10,500 BP. Multidisciplinary investigations at the site provide a detailed record of environmental and cultural changes on San Miguel Island during this time period. This record includes evidence for the local or regional extinction of a number of animal species, as well as some of the earliest evidence for the human use of boats and other maritime activities in the Americas. Data from Daisy Cave contribute to a growing body of evidence that Paleoindians had adapted to a wide variety of New World environments prior to 10,000 PB. Analysis of shell-charcoal pairs, along with isotopic analysis of associated marine shells, supports the general validity of marine shell dating, but also provides evidence for temporal fluctuations in the reservoir effect within the Santa Barbara Channel region.

Point Conception, California, has long been recognized as an environmental transition zone for both terrestrial and marine life forms occupying central and southern California. Recent archaeological investigations above and below Point Conception have revealed a number of differences in the archaeological records of the respective regions. Late Period coastal middens north of Point Conception contain higher densities of shellfish remains and smaller quantities of fish and sea mammal remains than coastal midden deposits along the Santa Barbara Channel to the east, where Late Period sites contain substantial quantities of fish and sea mammal remains. These differences in the archaeological records appear to be determined, in large part, by differences in the relative resource abundances in the two regions. However, to understand more completely the variability in subsistence strategies, one must go beyond simply documenting differences in food resource abundance in the environment. It is proposed that the economics of resource exploitation must be considered in the formulation of any adequate explanation of resource variability.

We demonstrate variable radiocarbon content within 2 historic (AD 1936) and 2 prehistoric (about 8200 BP and 3500 BP) Mytilus californianus shells from the Santa Barbara Channel region, California, USA. Historic specimens from the mainland coast exhibit a greater range of intrashell variability (i.e. 180–240 14C yr) than archaeological specimens from Daisy Cave on San Miguel Island (i.e. 120 14C yr in both shells). δ13C and δ18O profiles are in general agreement with the up welling of deep ocean water depleted in 14C as a determinant of local marine reservoir correction (ΔR) in the San Miguel Island samples. Upwelling cycles are difficult to identify in the mainland specimens, where intrashell variations in 14C content may be a complex product of oceanic mixing and periodic seasonal inputs of 14C-depeleted terrestrial runoff. Though the mechanisms controlling ΔR at subannual to annual scales are not entirely clear, the fluctuations represent significant sources of random dating error in marine environments, particularly if a small section of shell is selected for accelerator mass spectrometry (AMS) dating. For maximum precision and accuracy in AMS dating of marine shells, we recommend that archaeologists, paleontologists, and 14C lab personnel average out these variations by sampling across multiple increments of growth.

For at least 100,000 yr, marine shell beads have been important ornamental and symbolic artifacts intimately associated with the behavior of anatomically modern humans. In California, giant rock scallop (Hinnites multirugosus) beads were once thought to have been used only for the last 1000 yr, where they were considered to be markers of high social status among the Chumash Indians of the Santa Barbara Channel region. Direct accelerator mass spectrometry (AMS) radiocarbon dating of 1 giant rock scallop ornament and 2 beads from San Miguel Island extends the use of this shell for personal adornment to at least 8000 cal BP. Our study emphasizes the importance of direct AMS 14C dating of artifacts to enhance cultural chronologies and clarify the antiquity of various technologies and associated behaviors. Our results also caution archaeologists when equating artifact rarity with sociopolitical complexity.

SUMMARYStudies of marine reserves typically focus upon differences in the size and abundance of target organisms inside versus outside reserve borders, but they seldom provide spatially explicit measurements of how reserves influence mortality rates. This study investigated mortality rates for female California spiny lobster (Panulirus interruptus) at multiple sites inside and outside of three marine reserves at the Santa Barbara Channel Islands, California, USA. Mean total mortality (Z) of female lobsters was lower at sites inside reserves (Z = 0.22 [± 0.05 SE]) than at sites outside reserves (Z = 0.59 [± 0.02 SE]). Mean mortality at all sites inside reserves, and among sites near reserve centres (where Z = 0.17 [± 0.05 SE]), was similar to estimates of natural mortality for other temperate spiny lobster species. Among sites inside reserves, there was a positive relationship between mortality and proximity to reserve borders, but this relationship was absent among sites outside reserves. Mortality estimates were much more variable among sites inside reserves than at sites in fished areas. This variation is probably due to differential emigration rates from the three reserves, as well as site-specific ecological factors that influence population structure, demonstrating the importance of spatially explicit reserve sampling and understanding how ecological heterogeneity influences fisheries models.

Anthropogenic oil in the ocean is of great concern due to its potential immediate and long-term impacts on the ecosystem, economy, and society, leading to intense societal efforts to mitigate and reduce inputs. Sources of oil in the ocean (in the order of importance) are natural marine seepage, run-off from anthropogenic sources, and oil spills, yet uncertainty and variability in these budgets are large, particularly for natural seepage, which exhibits large spatial and temporal heterogeneity on local to regional scales. When source inputs are comparable, discriminating impacts is complicated, because petroleum is both a bioavailable, chemosynthetic energy source to the marine ecosystem and a potential toxic stressor depending on concentration, composition, and period of time. This synthesis review investigates the phenomena underlying this complexity and identifies knowledge gaps. Its focus is on the Coal Oil Point (COP) seep field, arguably the best-studied example, of strong natural marine hydrocarbon seepage, located in the nearshore, shallow waters of the Northern Santa Barbara Channel, Southern California, where coastal processes complicate oceanography and meteorology. Many of our understandings of seep processes globally are based on insights learned from studies of the oil and gas emissions from the COP seep field. As one of the largest seep fields in the world, its impacts spread far as oil drifts on the sea surface and subsurface, yet much remains unknown of its impacts.

AbstractAnalysis of a buried deposit in the Diamond Valley of southern California has revealed well-preserved pollen, wood, and diatom remains. Accelerator mass spectrometry dates of 41,200±2100 and 41,490±1380 14C yr B.P. place this deposit in marine isotope stage 3. Diatoms suggest a shallow lacustrine environment. Pollen data suggest that several plant communities were present near the site, with grassland, scrub, chaparral, forest, and riparian communities represented. Comparison with modern pollen suggests similarities with montane forests in the nearby San Bernardino and San Jacinto ranges, indicating vegetation lowering by at least 900 m elevation and temperatures 4°–5°C cooler than today. An increase in high-elevation conifer pollen documents climatic cooling near the profile top. Early-profile diatoms are typical of warm water with high alkalinity and conductivity, whereas later diatoms suggest a higher flow regime and input of cooler water into the system. We suggest that the sequence is part of the cooling phase of an interstadial Dansgaard–Oeschger cycle. Records of the middle Wisconsin period are rare in southern California, but the Diamond Valley site is similar to records from Tulare Lake in the San Joaquin Valley and the ODP Site 893A record from Santa Barbara Basin. It is probable that the Diamond Valley assemblage is a local expression of a vegetation type widespread in the ranges and basins of southwestern California during the middle Wisconsin.

ABSTRACT Linking beach tar with sources in a complex natural marine seepage area presents numerous challenges. Efforts at Coal Oil Point (COP), CA included beach tar distribution surveys, oil slick tracking, sampling, and chemical analysis, underwater scuba surveys, aerial surveys, and numerical modeling. Despite a wind from the east and current to the west, a slick was tracked initially north from its source, presumably due to spreading, then it drifted east, ending in a kelp bed off COP. Sample chromatograms showed mixing with another oil slick by the appearance of a heavier series of n-alkane peaks where the trajectory changed direction. Trajectory simulations suggested that interface currents were poorly described by parameterizations of wind and surface currents, and/or the existence of small-scale circulations not resolved by CODAR or the drift buoy. Detailed tar accumulation surveys covered 175-m (4400 m2) of COP beach where tar accumulation generally is greatest. Maximum total beach tar observed was 1.5 kg, with significant variability. Modeling suggested a similar source location for the three analyzed surveys. Analysis also suggested kelp canopies can play a significant roll in the arrival time and location of beach tar by blocking onshore transport. However, wind, current, and kelp conditions were such that much of the variability in tar accumulation for these surveys probably was from source emission variability.

A video-monitored oil capture tent was developed and deployed during two field trips to quantify oil emissions from several sites in nearshore waters off Summerland Beach in Santa Barbara County, California, at a water depth of ∼5 m. The tent was a tall, inverted polyvinyl chloride plastic cone, which funneled oil into a video-observed sample collection jar. Sample jars were periodically retrieved and analyzed to determine oil and gas emissions at two seeps not associated with physical structures, and a suspected abandoned oil well, designated S-3. Oil and gas emissions at the seeps were ∼1 ml day−1 and ∼90 L day−1, respectively. At the S-3 site, emissions were 51 ml oil day−1 and 0.35 L gas day−1. The size distribution of bubbles at S-3 was sharply peaked at 1500-μm radius, and bubbles rose significantly slower than equivalent size non-oily bubbles, demonstrating the effect of oil on buoyancy loss. A method was developed to estimate from the measured rise velocities the oil-to-gas ratio of each bubble, calibrated with the sample analysis oil and gas fluxes. Autocorrelation showed strong peaks at 64.3 s and 120.0 s period, which were likely related. Other autocorrelation peaks at multiples of 8.2 s corresponded to Fourier spectrum peaks at 8 s and 23.4 s, and were proposed to relate to wave swell-induced surge. Other spectral peaks were observed at 4.9 s, 13.0 s, and 45-50 s period.

Abstract Low-level winds along the Californian coast during spring and early summer are typically strong and contained within the cool, well-mixed marine boundary layer (MBL). A temperature inversion separates the MBL from the warmer free troposphere. This setup is often represented by a two-layer shallow-water system with a lateral boundary. Near a prominent point such as Point Conception, California, the fast-moving MBL flow is supercritical and can exhibit distinct features including a compression bulge and an expansion fan. Measurements from the University of Wyoming King Air research aircraft on 19 May 2012 during the Precision Atmospheric MBL Experiment (PreAMBLE) captured wind in excess of 14 m s−1 off of Point Conception under clear skies and wind ~2 m s−1 east of San Miguel in the California Bight. A compression bulge was identified upwind of Point Conception. When the flow rounds the point, the MBL undergoes a near collapse and there is a spike in MBL height embedded in the general decrease of MBL height with greater turbulence just downwind that is associated with greater mixing through the inversion layer. Lidar and in situ measurements reveal that transport of continental aerosol is present near the pronounced MBL height change and that there is a complex vertical structure within the Santa Barbara Channel. Horizontal pressure gradients are obtained by measuring the slope of an isobaric surface. Observations of wind and pressure perturbations are able to be linked through a simple Bernoulli relationship. Variation of MBL depth explains most, but not all of the variation of the isobaric surface.

We examined the relative investment in somatic, gonadal, and liver growth, as well as a measure of immune function, in a marine species of fish (cabezon, Scorpaenichthys marmoratus (Ayres, 1854)) reared under different ambient temperature regimes (mean temperatures: 14.8 °C in Santa Barbara and 12.7 °C in Cayucos; both in California, USA). We predicted that fish reared in colder water would exhibit more pronounced trade-offs among growth, development, and immune parameters than fish in warmer water, and that females would have more pronounced trade-offs than males due to increased energy requirements for ovary development. We found immune function and liver investment were positively related in cold-water fish, but unrelated in warmer water fish. Immune function positively covaried with gonadal investment, but was not associated with somatic investment. Gonadal investment was negatively related to somatic investment, but this was driven by females, as there was no relationship between gonad development and somatic growth in males. We also found that the sexes differed in the relationship between gonadal and liver investments, in which females again exhibited a negative association but males exhibited a positive association. These results indicate that developmental investment strategies in cabezon are flexible and may be both context-specific and sex-specific.

Abstract Research flights during the Precision Atmospheric Marine Boundary Layer Experiment (PreAMBLE) in Southern California during May–June 2012 focused on three main features found in the nearshore marine boundary layer (MBL): the coastal jet (10 flights), the Catalina eddy (3 flights), and the initiation of a southerly surge (1 flight). Several topics were examined with case studies, but results from individual events may not represent typical conditions. Although these flights do not constitute a long-term set of data, observations from PreAMBLE are used to find common features. Two main topics are addressed: the MBL collapse into the expansion fan, and the subsequent transition into the Santa Barbara Channel (SBC). The midmorning to late afternoon flights occur during moderate to strong northerly wind. Slope of the MBL in the expansion fan varies and wave perturbations can be embedded within the expansion fan. As the cool MBL flow turns into the SBC, it moves underneath a deeper and warmer MBL that originates from the southeast over the warmer ocean. The temperature inversion between the cool and warm MBL erodes toward the east until there is only the inversion between the warm MBL and free troposphere. The dissipation of the lower layer into the SBC observed by the aircraft differs from previous conceptual models that depict a continuous MBL that thins and then deepens again in the SBC, which was inferred from sparse observations and numerical simulations. Only one flight within the SBC detected a hydraulic jump from 100 to 200 m above the surface.

ABSTRACTMarine hydrocarbon seeps supply oil and gas to microorganisms in sediments and overlying water. We used stable isotope probing (SIP) to identify aerobic bacteria oxidizing gaseous hydrocarbons in surface sediment from the Coal Oil Point seep field located offshore of Santa Barbara, California. After incubating sediment with13C-labeled methane, ethane, or propane, we confirmed the incorporation of13C into fatty acids and DNA. Terminal restriction fragment length polymorphism (T-RFLP) analysis and sequencing of the 16S rRNA and particulate methane monooxygenase (pmoA) genes in13C-DNA revealed groups of microbes not previously thought to contribute to methane, ethane, or propane oxidation. First,13C methane was primarily assimilated byGammaproteobacteriaspecies from the familyMethylococcaceae,Gammaproteobacteriarelated toMethylophaga, andBetaproteobacteriafrom the familyMethylophilaceae. Species of the latter two genera have not been previously shown to oxidize methane and may have been cross-feeding on methanol, but species of both genera were heavily labeled after just 3 days.pmoAsequences were affiliated with species ofMethylococcaceae, but most were not closely related to cultured methanotrophs. Second,13C ethane was consumed by members of a novel group ofMethylococcaceae. Growth with ethane as the major carbon source has not previously been observed in members of theMethylococcaceae; a highly divergentpmoA-like gene detected in the13C-labeled DNA may encode an ethane monooxygenase. Third,13C propane was consumed by members of a group of unclassifiedGammaproteobacteriaspecies not previously linked to propane oxidation. This study identifies several bacterial lineages as participants in the oxidation of gaseous hydrocarbons in marine seeps and supports the idea of an alternate function for somepmoA-like genes.

The ecology of an epibiont may depend not only on the dynamics of its biogenic habitat but also on microclimate variation generated within aggregations of its host, a process called physical ecosystem engineering. This study explored variation in the abundance and demography of Membranipora, a suspension-feeding bryozoan, within forests of giant kelp (Macrocystis pyrifera) off the coast of Santa Barbara, California, USA. First, we assessed differences in Membranipora abundance between the edge and interior of kelp forests. The occurrence of Membranipora on kelp blades and its percent cover on occupied blades were higher along forest edges than interiors. Second, we conducted observational studies and field experiments to understand spatial variation in substrate longevity, colony mortality, larval recruitment, and colony growth rates. A higher density of recruits and colonies occurred along forest edges than interiors, suggesting kelp acts like a sieve, whereby larvae settle to edge blades first. Moreover, growth rates along the edge were up to 45% higher than forest interiors. Reduced current speeds, combined with feeding by exterior colonies, may have lowered the uptake of suspended food particles by interior colonies. These results suggest that variation in Membranipora abundance is due in part to differences in colony growth between forest edges and interiors, and not solely the result of recruitment limitation. Our results highlight the importance of ecosystem engineers in influencing the ecological dynamics of epiphytic flora and fauna in marine systems.

ABSTRACT The natural oil seeps off Coal Oil Point (Santa Barbara), California, release an estimated 100–150 bbl of oil per day to the marine environment. This project proposed to conduct a series of dispersant trials using these seeps to intercalibrate NOAA's Scientific Monitoring of Advanced Response Technologies (SMART) UV/Fluorescence-based protocols with finite measurements of dissolved aromatics and dispersed oil droplets in the water column and to evaluate a unique oil-boomldispersant-application technology (NeatSweep). Following an elaborate and lengthy permitting process including cooperation from multiple regulatory agencies and organizations, laboratory tests indicated that although fresh produced oil from nearby Platform Holly could be treated (>70% effectiveness), dispersing the weathered 11° API gravity seep oil was totally ineffective (0%). Limited field tests then verified the laboratory findings that the seep oil could not even be dispersed with Corexit 9500, a commonly used dispersant for heavily weathered and viscous oils. Lacking reasonable alternatives (including the use of intentional spills), the project was halted before full-scale field implementation. This paper documents the development of the research plan, the steps required to obtain the necessary permits, and the results from the limited laboratory and field tests that were completed. The planning and permitting efforts for this project are provided so that others with similar needs or goals might benefit. A brief discussion is provided on the limitations of using natural seep oils for spill response research and on the difficulties with spill-of-opportunity research during actual spill events. The importance of controlled experimental discharges of oil is discussed along with the pros and cons of such deliberate spills.

Abstract Active fold-and-thrust belts can potentially accommodate large-magnitude earthquakes, so understanding the structure in such regions has both societal and scientific importance. Recent studies have provided evidence for large earthquakes in the Western Transverse Ranges of California, USA. However, the diverse set of conflicting structural models for this region highlights the lack of understanding of the subsurface geometry of faults. A more robust structural model is required to assess the seismic hazard of the Western Transverse Ranges. Toward this goal, we developed a forward structural model using Trishear in MOVE® to match the first-order structure of the Western Transverse Ranges, as inferred from surface geology, subsurface well control, and seismic stratigraphy. We incorporated the full range of geologic observations, including vertical motions from uplifted fluvial and marine terraces, as constraints on our kinematic forward modeling. Using fault-related folding methods, we predicted the geometry and sense of slip of the major faults at depth, and we used these structures to model the evolution of the Western Transverse Ranges since the late Pliocene. The model predictions are in good agreement with the observed geology. Our results suggest that the Western Transverse Ranges comprises a southward-verging imbricate thrust system, with the dominant faults dipping as a ramp to the north and steepening as they shoal from ∼16°–30° at depth to ∼45°–60° near the surface. We estimate ∼21 km of total shortening since the Pliocene in the eastern part of the region, and a decrease of total shortening west of Santa Barbara down to 7 km near Point Conception. The potential surface area of the inferred deep thrust ramp is up to 6000 km2, which is of sufficient size to host the large earthquakes inferred from paleoseismic studies in this region.

It might seem incongruous that a research focused organisation such as the International Union for Pure and Applied Chemistry would pay attention to an issue as pragmatic as oil spills. After all, an oil spill tends to be viewed as a very practical matter, its issues characterised by loss of a valuable commercial product, damage to the environment, high costs of clean up, high legal liabilities, and very much media attention. Oil spills are not generally considered a pure or even applied chemistry issue. However, this would be a very short-sighted interpretation. Effectively every element of an oil spill, whether environmental, physical, operational or legal, is related to the complex chemistry of the oil and its breakdown products released to the environment. Indeed, it would be safe to say that if petroleum were a simple chemical product, the difficulties inherent in clean up of an oil spill would be much reduced, no matter what the origin or cause of the spill.The chemical nature of oil is directly related to the fate and environmental impacts of spilled oil, whether on water or on land, and to the effectiveness of the diversity of countermeasures which might be deployed. While evaluation of the effects of spilled oil on the environment receives much attention in forums with a biological or toxicological focus, which often do take into consideration chemical factors, the complex topic of the chemistry of oil spills in direct relation to countermeasures is examined more rarely. The various chapter in this document discuss a diversity of oil spill countermeasures, and target the chemical and consequently physical behaviour of oil which determines its characteristics at the time of the spill. While oil spills occur in fresh and salt waters, and on land, marine oil spills remain the larger issue - there tends to be more oil spilled, environmental problems are more complex, and countermeasures are more difficult to implement. The following papers generally reflect and review the current state of knowledge in their topic area, and are representative of the most recent surge in research and development activities, stimulated particularly by the Exxon Valdez spill in Prince William Sound, Alaska in 1989. It appears that oil spill research undergoes cycles of interest, activity and funding, linked to key oil spills. Previously, the Torrey Canyon spill in the English Channel off Land's End, in the United Kingdom in 1967 provided general incentive for research and development, as did the Amoco Cadiz spill off the coast of Brittany, France in 1978. Other oil spills, such as the 1968 Santa Barbara Channel, California spill, or the Braer spill off the Shetlands in 1993, among others, have also stimulated specific areas of research and development on the basis of issues that arose in their particular spill scenario.The articles in this publication have been contributed by recognised international experts in the spill response field, and have received the benefit of peer review. The articles are representative of the major categories of oil spill response research, spanning a wide range of technologies, supportive knowledge and experience, to include reviews of:This collection of review articles concludes with an evaluation of oil spill response technologies for developing nations, appropriately so since that is where much of the oil development and production currently occurs in the world.One area which has seen much recent expansion is that of the essential linkage between detailed understanding of spilled oil physical/chemical properties and the effectiveness of response countermeasures. Crude oils and oil products are known to differ greatly in physical and chemical properties and these tend to change significantly over the time course of spilled oil recovery operations. Such changes have long been recognised to have a major influence on the effectiveness of response methods and equipment, which increases the time and cost of operations and risk of resource damage. All countermeasures are influenced, whether sorbents, booms, skimmers, dispersants, burning of oil and so forth. The incentive is for a rapid and accurate method of predicting changes in oil properties following spill notification, which could be used in both the planning and early phases of spill response, including an initial specific selection of an effective early countermeasure. In later stages of the response, more accurate planning for clean up method and equipment deployment would shorten response time and reduce costs. An additional benefit would be more effective planning for recall of equipment not needed, as well as potentially decreasing the risk of natural resource damage and costs due to more effective spilled oil recovery. The concept of "Windows of Opportunity" for oil spill response measures has been derived from multiple investigations in industry and government research organisations.Although dispersants have been used to date in almost one hundred large spills world-wide, government approval for dispersant use has long been inhibited by a lack of understanding of the factors determining the operational effectiveness of dispersants, and the environmental trade-offs which might need to be made to protect sensitive areas from spilled oil. Recent advances in chemical dispersant development, formulation of low toxicity dispersants with broader application, and better understanding of dispersant fate and effects have combined to a more ready acceptance of this countermeasure by many, although not yet all, regulatory authorities throughout the world. In addition to the category of dispersants, chemical countermeasures include many diverse agents, such as beach cleaners, demulsifiers, elasticity modifiers and bird cleaning agents, each with a unique and specialised role in clean up activities. However, the concerns for the use of these 'alternative chemicals' relate to the interpretation and application of toxico-ecological data to the decision process. If in the future the ecological issues concerning chemical treating agents can be further successfully resolved, the oil spill response community will have an increased range of options for response. However, extensive laboratory and field testing is required in many instances for new chemical dispersant materials and demulsifiers to improve the effectiveness of these materials on weathered oils and water in oil emulsions. The acceptance of in situ (i.e. 'on site') burning of spilled oil has been limited by valid operational concerns about the integrity of fireproof booms, the limited weather window for burning due to the rapid emulsification of oils, the need to develop methods for the ignition of emulsified and weathered oils, and public concerns about the toxicity of the smoke generated during burning. However, burning provides an option, another tool in the tool-box, for the responder called in to combat an oil spill. Burning decreases the amount of oil that must be collected mechanically, thus reducing cleanup costs, storage, transportation, and oily waste disposal requirements. It also would decrease potential contact with sensitive marine and coastal environments and consequently reduce the potential for associated damage costs. Laboratory and field studies over the last ten years have addressed essential information requirements for feasibility, techniques, and effectiveness, as well as health and safety. The results of research in situ burning has led to its acceptance in a number coastal jurisdictions throughout the world, prompting the response industry to purchase and position in situ burning equipment and train its operators to use this alternative technology in approved regions.Although not a direct recovery measure in itself, the application of remote sensing to oil spill response assists in slick identification, tracking, and prediction, which in many instances is an early requirement for effective response. An inadequate ability to see spilled oil seriously reduces effectiveness of oil spill response operations. Conversely, good capability to detect spilled oil, especially areas of thick oil, at night and other conditions of reduced visibility could more than double response effectiveness and greatly enhance control of the spill to minimise damage, especially to sensitive shorelines. Advances have been made in both airborne and satellite remote sensing. It has become possible to move from large and expensive to operate airborne systems to small aircraft, more widely available and practical for spill response operators. Also, the limitations in delayed data processing and information communication are being overcome by development of systems operating in functional real-time, which is essential for enhanced response capacity. Spill detection using satellites has also advanced markedly since 1989, with the ongoing intention to provide coverage of oil spill areas as early warning, or when flying by aircraft is not possible. An early useful application was an ERS-1 satellite program for detection of oil slicks, launched in 1992. More recently, spill detection capability has been developed for the Canadian Radarsat satellites, ERS-2 and a few other satellite programs.The topic of bioremediation of spilled oil, that is, to use microbes to assist in clean up, is a corollary to the deployment of traditional countermeasures. It had not seen much operational or regulatory support until the Exxon Valdez spill, where it was initiated as a spill mitigation method, establishing bioremediation as a major oil spill R&D area. Bioremediation of oil spills was defined as being one of three different approaches: enhancement of local existing microbial fauna by the addition of nutrients to stimulate their growth; 'seeding' the oil impacted environment with microbes occurring naturally in that environment; and, inoculating the oil impacted environment with microbes not normally found there, including genetically engineered bacterial populations. Research emphasis and regulatory countenance has been predominantly on the first approach. Evaluation of operational utility of is continuing to identify conditions under which bioremediation can be used in an environmentally sound and effective manner, and to make recommendations to responders for the implementation of this technology.The issue of hydrocarbon toxicity has been examined in petroleum refinery and petrochemical workers for more than a decade, and experimentally in test animals for a much longer period. However, there has been little specific information available on the effects of oil spills on human health, neither for oil spill response workers nor for incidentally exposed individuals. More recently, as reviewed in an article on human health effects in this publication, some reports have been published of skin irritation and dermatitis from exposure of skin to oil during cleanup, as well as nausea from inhalation of volatile fractions. Although there are to date no epidemiological studies of exposure by oil spill workers to petroleum hydrocarbons, the matter is drawing increasing attention.One of the more important issues surrounding the choice and extent of application of oil spill countermeasures is knowledge about the ecological effectiveness of such response, that is, the balance point between continuation of clean up activities and letting the environment take care of its own eventual recovery. It is the last point which has driven much of the discussions and research associated with the concept of 'how clean is clean', or, how much cleanup is enough or too much. The results of such diverse research efforts are being used increasingly and successfully to link spilled oil chemistry to countermeasures practices and equipment. The advances are being integrated into more effective response management models and response command systems. In summary, applied chemical research and development has actively contributed to an enhancement in oil spill response capability. Nonetheless, it seems that the pace of oil spill research and countermeasures development is slowing. The decrease is at least temporally associated with a decline in the frequency and magnitude of oil spills in recent years. Spill statistics gathered by organisations such as the publishers of the Oil Spill Intelligence Report, show that world-wide oil spill incidence and volume have continued to decline since the time of the Exxon Valdez spill event (see the Oil Spill Intelligence Report publication "International Oil Spill Statistics: 1997", Cutter Information Corp.). It is probably not coincidental that the amount of funding available for oil spill research and development, from both government and private industry sources, has declined similarly. In that context, the following articles are more a statement of currently accepted knowledge and practice, rather than being a 'snapshot in time' of intense ongoing research activities. The articles serve to capture the applied chemistry knowledge and experience of practitioners in a complex field, application of which remains essential for the development of improved oil spill countermeasures, and their effective use in real spill situations.

The Transverse Ranges of southern California are a region of active transpression on the western margin of North America that hosts some of the world’s highest uplift rates at the Ventura anticline. Yet, the manner in which rock uplift rates change along strike from Ventura to the westernmost Transverse Ranges and the structures that may be responsible for this uplift remain unclear. Here, we quantified rock uplift rates within the westernmost 60 km of the Transverse Ranges by obtaining new age constraints from raised beach and shoreface deposits from marine terraces along the Gaviota coast. Twelve radiocarbon (seven sites) and eight luminescence (six sites) ages, ranging from ca. 50 to 40 k.y. B.P. and ca. 56 to 43 ka, respectively, consistently suggest that the first emergent terrace dates to marine isotope stage (MIS) 3, rather than MIS 5a as previously reported for the western Gaviota coast. These younger ages yield rock uplift rates between 0.8 ± 0.3 and 1.8 ± 0.4 m/k.y., i.e., over five times higher than previous estimates for this region. The spatial distribution of rock uplift rates and the abrupt along-strike changes in marine terrace elevations favor a regional tectonic model with a step-wise change in rock uplift across the south branch of the Santa Ynez fault. The south branch of the Santa Ynez fault appears to separate two regional tectonic blocks, characterized by rock uplift rates of ∼1.3−1.6 m/k.y. to the east and slightly lower rates to the west (∼0.8−1.4 m/k.y.). Our observations suggest that coastal rock uplift is primarily accommodated by deeply rooted far-field structures such as the offshore Pitas Point−North Channel fault system and the Santa Ynez fault, and that smaller through-going structures impart second-order controls and locally accommodate short-wavelength (<10-km-long strike length) deformation. These results imply that although the rates of rock uplift decline westward along strike, the westernmost portion of the western Transverse Ranges nonetheless accommodates relatively high (>1 m/k.y.) rock uplift rates at a significant distance (>50 km) from the rapidly uplifting (6−7 m/k.y.) Ventura anticline, and >100 km from the prominent restraining bend (“Big Bend”) in the San Andreas fault. The new constraints on the geometry of Quaternary-active structures and regional rates of fault-related deformation have implications for regional earthquake source models and seismic hazard assessment in the highly populated southern California coast region.

A 51-cm core (SBB-8-2012) from the depo-center of Santa Barbara Basin (SBB), California has been dated by 210Pb dating and varve counting, spanning a depositional history during 1815-2011 CE. A total of 89 AMS 14C measurements on samples from 66 horizons, including animal cartilage, shell and total organic carbon (TOC) in the sediments show apparent 14C ages between 500 and 4000 yr BP. Among these AMS dates, D14C values measured in 78 samples from 62 horizons vary in the range of -64.3‰ to -383.8‰. The 14CTOC ages much older than predicted from our sedimentation model are influenced by the input of terrigenous sediments, changes in ocean circulation, biological input and carbon remineralization. Three strong old 14CTOC excursions at 1964~69, 1884~87 and 1819~21 CE indicate higher old carbon input caused by some unusual events (e.g., oil spill, flood event and earthquake). On multi-decadal timescales, the D14CTOC shifts in three zones were mainly caused by changes in fossil carbon emission from the seafloor, fraction of marine productivity to terrigenous input of organic carbon (OC) and the atmospheric nuclear bomb testing input of 14C into the SBB. On interannual to decadal timescales, variations of D14CTOC correspond to El Niño-Southern Oscillation effects. During the La Niña period, stronger upwelling and northerly California Current bring nutrient-enriched water into SBB and lead to higher productivity hence more marine OC with higher D14CTOC. In addition, reduced terrigenous input of OC with lower D14C under less coastal rainfall during La Niña could further elevate the D14CTOC. Lower scanning XRF (K+Ti)/2 (indicating lower terrigenous input), higher scanning XRF Sr/Ti as well as acid-leachable elements (reflecting higher biogenic components), and higher D14CTOC occur during La Niña. During the El Niño period, the phenomena are opposite. Spectrum analyses of the Southern Oscillation Index (SOI) and the D14CTOC as well as the comparison of SOI and SBB-8-2012 records support our scenarios.

Vessel strikes have been documented around the world and frequently figure as a top human cause of large whale mortality. The shipping lanes in the Santa Barbara Channel, California and nearby waters have some of the highest predicted whale mortality from vessel strikes in the United States waters of the eastern Pacific. Beginning in 2007, National Oceanographic and Atmospheric Administration requested voluntary vessel speed reductions (VSRs) for vessels greater than 300 GT traveling in the Santa Barbara Channel shipping routes to decrease whale mortality from ship strikes. We employed a ship strike model using whale density data and automatic identification system (AIS) vessel data to estimate mortality under several management scenarios. To assess the effect of the VSR on strike mortality, we bootstrapped speeds from vessels greater than 19 m long that transited when no VSR was in place. Finally, we calculated the predicted mortality for hypothetical cooperation scenarios by artificially adding speed caps post-hoc to real vessel transits. For 2012–2018, we estimated that in our study area on average during summer/fall (June–November) 8.9 blue, 4.6 humpback, and 9.7 fin whales were killed from ship strikes each year (13–26% greater than previously estimated). We evaluated winter/spring (January–April) humpback mortality for the first time, resulting in an estimate of 5.7 deaths on average per year. Poor cooperation with the VSR led to low (5% maximum) to no reductions in the estimated number of strike mortalities. Evaluating potential scenarios showed that if 95% cooperation occurred in the lanes, whale deaths there would decrease by 22–26%. Adding VSRs with similar cooperation levels at the northern end of the Santa Barbara Channel and south of Channel Islands National Marine Sanctuary could decrease estimated strike mortalities in those areas by 30%. If VSRs were added and cooperation reached 95% there and in the lanes, we estimate a 21–29% decrease in vessel strike mortalities could be attained relative to estimated mortality in the entire study area. To decrease the vessel strike related whale mortalities in this region, we recommend expanding the VSR areas and increasing cooperation voluntarily, or considering mandatory speed limits if desired cooperation levels cannot otherwise be met.

Abstract The California horn shark (Heterodontus francisci) is a small demersal species distributed from southern California and the Channel Islands to Baja California and the Gulf of California. These nocturnal reef predators maintain small home-ranges as adults, and lay auger-shaped egg cases that become wedged into the substrate. While population trends are not well documented, this species is subject to fishing pressure through portions of its range and has been identified as vulnerable to overexploitation. Here we present a survey of 318 specimens from across the range, using mtDNA control region sequences to provide the first genetic assessment of H. francisci. Overall population structure (ΦST = 0.266, P < 0.001) is consistent with limited dispersal as indicated by life history, with two distinct features. Population structure along the continuous coastline is low, with no discernable breaks from Santa Barbara, CA to Bahia Tortugas (Baja California Sur, Mexico); however, there is a notable partition at Punta Eugenia (BCS), a well-known biogeographic break between tropical and subtropical marine faunas. In contrast, population structure is much higher (max ΦST = 0.601, P < 0.05) between the coast and adjacent Channel Islands, a minimum distance of 19 km, indicating that horn sharks rarely disperse across deep habitat and open water. Population structure in most elasmobranchs is measured on a scale of hundreds to thousands of kilometers, but the California Horn Shark has population partitions on an unprecedented small scale, indicating a need for localized management strategies which ensure adequate protection of distinct stocks.

California is a major shipping point for exports and imports across the Pacific Basin, has large commercial and recreational fisheries, and an abundance of marine recreational boaters. Each of these industries or activities requires either a port or harbor. California has 26 individual coastal ports and harbors, ranging from the huge sprawling container ports of Los Angeles and Long Beach to small fishing ports like Noyo Harbor and Bodega Bay. Almost all of California’s ports and harbors were constructed without any knowledge or consideration of littoral drift directions and rates and potential future dredging issues. Rather, they were built where a need existed, where there was a history of boat anchorage, or where there was a natural feature (e.g. bay, estuary, or lagoon) that could be the basis of an improved port or harbor. California’s littoral drift rates and directions are now well known and understood, however, and have led to the need to perform annual dredging at many of these harbors as a result of their locations (e.g. Santa Cruz, Oceanside, Santa Barbara, Ventura, and Channel Islands harbors) while other harbors require little or no annual dredging (e.g. Half Moon Bay, Moss Landing, Monterey, Redondo-King and Alamitos Bay). California’s coastal harbors can be divided into three general groups based on their long-term annual dredging volumes, which range from three harbors that have never been dredged to the Channel Islands Harbor where nearly a million cubic yards is removed on average annually. There are coastal harbors where dredging rates have remained nearly constant over time, those where rates have gradually increased, and others where rates have decreased in recent years. While the causal factors for these changes are evident in a few cases, for most there are likely a combination of reasons including changes in sand supply by updrift rivers and streams related to dam construction as well as rainfall intensity and duration; lag times between when pulses of sand added to the shoreline from large discharge events actually reach downdrift harbors; variations in wave climate over time; shoreline topography and nearshore bathymetry that determine how much sand can be trapped upcoast of littoral barriers, such as jetties and breakwaters, before it enters a harbor; and timing of dredging. While there is virtually nothing that can be done to any of these harbors to significantly reduce annual dredging rates and costs, short of modifying either breakwater or jetty length and/or configuration to increase the volume of sand trapped upcoast, thereby altering dredging timing, they are clearly major economic engines, but come with associated costs.

Certain benthic foraminifera thrive in marine sediments with low or undetectable oxygen. Potential survival avenues used by these supposedly aerobic protists include fermentation and anaerobic respiration, although details on their adaptive mechanisms remain elusive. To better understand the metabolic versatility of foraminifera, we studied two benthic species that thrive in oxygen-depleted marine sediments. Here we detail, via transcriptomics and metatranscriptomics, differential gene expression of Nonionella stella and Bolivina argentea, collected from Santa Barbara Basin, California, USA, in response to varied oxygenation and chemical amendments. Organelle-specific metabolic reconstructions revealed these two species utilize adaptable mitochondrial and peroxisomal metabolism. N. stella, most abundant in anoxia and characterized by lack of food vacuoles and abundance of intracellular lipid droplets, was predicted to couple the putative peroxisomal beta-oxidation and glyoxylate cycle with a versatile electron transport system and a partial TCA cycle. In contrast, B. argentea, most abundant in hypoxia and contains food vacuoles, was predicted to utilize the putative peroxisomal gluconeogenesis and a full TCA cycle but lacks the expression of key beta-oxidation and glyoxylate cycle genes. These metabolic adaptations likely confer ecological success while encountering deoxygenation and expand our understanding of metabolic modifications and interactions between mitochondria and peroxisomes in protists.