Mass and date at departure affect the survival of Ancient Murrelet Synthliboramphus antiquus chicks after leaving the colony

I compared the timing of colony departure and body mass of 53 Ancient Murrelet Synthliboramphus antiquus chicks that were retrapped as adults in Haida Gwaii, British Columbia, with those of 3992 chicks not retrapped. If the probability of recapture is a measure of survival, survival was related to both mass and date. Chicks that left the colony at 26 g or less had a lower chance of survival than heavier chicks, and those that left after the median date of departure survived better in some years than those that left earlier. The effect of date was not related to a seasonal change in departure mass because chick mass declined with departure date. I suggest that, because of heavy adult mortality during breeding, the timing of breeding in the Ancient Murrelet is based on a compromise between the optimum dates for chick and adult survival. This is in contrast to evidence from other, nonprecocial, seabirds.     

Macroaggregates and their phytoplanktonic components in the Southern California Bight

The abundances of phytoplankton associated with scuba-collected,visible macroaggregates (i e. ‘marine Snow’) fromvarious euphotic zone depths of several nearshore and offshoresites sampled in late winter/early spring and summer were determinedby microscopic study. Such phytoplankters have a different potentialfor predator/prey interactions than they would as separate individuals.Mean macroaggregate concentrations of 1.7–7 6 1^–1and mean individual macroaggregate sizes of 27–175 mm³were observed at the different sites. Phytoplankters associatedwith the macroaggregates were generally a few percent or lessof the total phytoplankton (range for numbers. 0.2–2.5%.range for carbon, 0.2–7.1%. n = 11). Of the taxonomicgroups, pennate diatoms in general showed high relative associationwith macroaggregates. Compared to the mean abundance of phytoplanktonin an equivalent volume of surrounding water, macroaggregateswere algal-enriched by factors ranging from 6.2–1300 (median,65) for numbers and 6.3–2500 (median. 110) for carbon(n = 11). ATP and chlorophyll a showed degrees of associationwith, and enrichment in. macroaggregates similar to that ofphytoplankton carbon. Before assessing the overall importanceof phytoplanktonic associations with aggregates in terms ofpelagic food web consequences, the abundances and algal compositionof the smaller microaggregates must also be known     

Population ecology of nitrifying Archaea and Bacteria in the Southern California Bight

Marine Crenarchaeota are among the most abundant microbial groups in the ocean, and although relatively little is currently known about their biogeochemical roles in marine ecosystems, recognition that Crenarchaeota posses ammonia monooxygenase (amoA) genes and may act as ammonia‐oxidizing archaea (AOA) offers another means of probing the ecology of these microorganisms. Here we use a time series approach combining quantification of archaeal and bacterial ammonia oxidizers with bacterial community fingerprints and biogeochemistry, to explore the population and community ecology of nitrification. At multiple depths (150, 500 and 890 m) in the Southern California Bight sampled monthly from 2003 to 2006, AOA were enumerated via quantitative PCR of archaeal amoA and marine group 1 Crenarchaeota 16S rRNA genes. Based on amoA genes, AOA were highly variable in time – a consistent feature of marine Crenarchaeota– however, average values were similar at different depths and ranged from 2.20 to 2.76 × 10⁴amoA copies ml^?1. Archaeal amoA genes were correlated with Crenarchaeota 16S rRNA genes (r² = 0.79) and the slope of this relationship was 1.02, demonstrating that the majority of marine group 1 Crenarchaeota present over the dates and depths sampled possessed amoA. Two AOA clades were specifically quantified and compared with betaproteobacterial ammonia‐oxidizing bacteria (β‐AOB) amoA genes at 150 m; these AOA groups were found to strongly co‐vary in time (r² = 0.70, P < 0.001) whereas AOA : β‐AOB ratios ranged from 13 to 5630. Increases in the AOA : β‐AOB ratio correlated with the accumulation of nitrite (r² = 0.87, P < 0.001), and may be indicative of differences in substrate affinities and activities leading to periodic decoupling between ammonia and nitrite oxidation. These data capture a dynamic nitrogen cycle in which multiple microbial groups appear to be active participants.     

Insights into Young of the Year White Shark, Carcharodon carcharias, Behavior in the Southern California Bight

A young of the year female white shark, Carcharodon carcharias, was tagged with a pop-up satellite archival tag off Southern California in early June of 2000. The tag was recovered after 28 days, and records of temperature, depth and light intensity were extracted. Depth and temperature records indicate a number of interesting behaviors, including a strong diurnal pattern. At night the shark remained in the top 50 m, often making shallow repetitive vertical excursions. Most dives below the mixed layer were observed during the day, 91% of which occurred from 05:00 to 21:00 h, with depths extending to 240 m. Many of the dives exhibited secondary vertical movements that were consistent with the shark swimming at the bottom (at depths from 9 to 165 m) where it was most likely foraging. The white shark experienced dramatic and rapid changes in temperature, and demonstrated a considerable tolerance for cold waters. Temperatures ranged from 9°C to 22°C, and although 89% of the total time was spent in waters 16–22°C, on some days the small shark spent as much as 32% of the time in 12°C waters. The deep dives into cold waters separate the white sharks from mako sharks, which share the California Bight nursery ground but appear to remain primarily in the mixed layer and thermocline. Movement information (derived from light-based geolocation, bottom depths and sea surface temperatures) indicated that the white shark spent the 28 days in the Southern California Bight, possibly moving as far south as San Diego, California. While the abundance and diversity of prey, warm water and separation from adults make this region an ideal nursery ground, the potential for interaction with the local fisheries should be examined.     

The Southern California Twin Register at the University of Southern California.

The Southern California Twin Register is the result of an effort to recruit twins of all ages in the city of Los Angeles and surrounding areas. The register currently includes an ethnically diverse sample of more than 2600 twin pairs. The most recently recruited pairs have been drawn primarily from computerized records of enrollments in local public school districts, and are comparable in sex and ethnic distributions to the general public school population. An ongoing twin study of social and moral development in children, based on 600 pairs of 9-year-old twins from this register, is also described briefly in this paper.     

Demersal fish assemblages in the Southern California Bight based on visual surveys in deep water

Between 1995 and 2006, manned submersible fish surveys were conducted on the sea floor throughout the Southern California Bight. A total of 401 dives (comprising 1,015 transects and 14,373 habitat patches) were made in waters between 19 and 365 m deep. All natural habitat types were included, although both soft sea floors and rocky reefs were surveyed more than any other type. A total of 717,526 fishes, representing a minimum of 137 species and 47 families, were observed. Rockfishes (genus Sebastes), with a minimum of 50 species and 647,495 individuals (90.2% of all fishes observed), dominated most of the habitats. The most abundant species, squarespot (Sebastes hopkinsi), halfbanded (Sebastes semicinctus), shortbelly (Sebastes jordani), and pygmy rockfishes (Sebastes wilsoni), are dwarf taxa that either school or aggregate. The most abundant non-rockfish species was the benthic and territorial blackeye goby (Rhinogobiops nicholsii). Both species richness and overall fish densities were highest in the shallowest sites. Most of the fishes in all habitats were small (≤20 cm TL long) and economically important species were generally uncommon. Forty-four species were found to be characteristic of the study area (occurring in at least 5% of the transects) and these species formed three faunal associations centered around depths of 62, 105, and 168 m. Based on size frequency distributions, at least 18 of the characteristic species exhibited ontogenetic movements, with young-of-the-year and older juveniles living in relatively shallow waters and larger individuals generally in deeper depths. In this study, the abundance of juvenile widow rockfish (Sebastes entomelas), and the virtual absence of adults, in southern California waters may demonstrate an ontogenetic northward movement of this species. This research implies that substantial harvesting of larger species by commercial and recreational fishers has helped alter some fish assemblages, allowing small and “weedy” species to thrive. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Using species-specific paleotemperature equations with foraminifera: a case study in the Southern California Bight

Species-specific paleotemperature equations were used to reconstruct a record of temperature from foraminiferal δ¹⁸O values over the last 25 kyr in the Southern California Bight. The equations yield similar temperatures for the δ¹⁸O values of Globigerina bulloides and Neogloboquadrina pachyderma. In contrast, applying a single paleotemperature equation to G. bulloides and N. pachyderma δ¹⁸O yields different temperatures, which has been used to suggest that these species record the surface-to-thermocline temperature gradient. In Santa Barbara Basin, an isotopically distinct morphotype of G. bulloides dominates during glacial intervals and yields temperatures that appear too cold when using a paleotemperature equation calibrated for the morphotype common today. When a more appropriate paleotemperature equation is used for glacial G. bulloides, we obtain more realistic glacial temperatures. Glacial–interglacial temperature differences (G–I ΔT) calculated in the present study indicate significant cooling (8–10°C) throughout the Southern California Bight during the last glacial maximum (LGM). The magnitude of glacial cooling varies from 8°C near the middle of the Southern California Bight (Tanner Basin and San Nicolas Basin) to 9°C in the north (Santa Barbara Basin) and 9.5–10°C in the south (Velero Basin and No Name Basin). Our temperature calculations agree well with previous estimates based on the modern analog technique. In contrast, studies using N. pachyderma coiling ratios, U^k′₃₇ indices, and transfer functions estimate considerably warmer LGM temperatures and smaller G–I ΔT.     

Age‐specific recruitment and natality of California sea lions at San Miguel Island,California

We conducted a 15 yr mark‐resight study of branded California sea lions (Zalophus californianus) at San Miguel Island, California, to estimate age‐specific recruitment and natality of the population. We used the Schwarz and Stobo model to estimate sighting, survival, recruitment, timing of births, abundance, and age‐specific natality from sighting histories of 1,276 parous females. The advantage of this approach was that the reproductive status of females did not have to be known for all females of reproductive age. Probability of recruitment into the reproductive population began at age 3 or 4, peaked between ages 5 and 7, and slowly declined. Age‐specific natality was similar for ages 4–16 but declined after age 17, suggesting that reproductive senescence occurs in older females. The average annual natality for parous females 4–16 yr of age was 0.77 (SE = 0.03); natality declined to 0.56 (SE = 0.10) for parous females 17–21 yr of age. Natality for both age classes was reduced during El Niño conditions by 24% and 34%, respectively. In addition to reducing natality, El Niño events may result in a delay of recruitment if females experience El Niño conditions before they turn 4 yr of age.     

Temporal variability and coherence of euphotic zone bacterial communities over a decade in the Southern California Bight

Time-series are critical to understanding long-term natural variability in the oceans. Bacterial communities in the euphotic zone were investigated for over a decade at the San Pedro Ocean Time-series station (SPOT) off southern California. Community composition was assessed by Automated Ribosomal Intergenic Spacer Analysis (ARISA) and coupled with measurements of oceanographic parameters for the surface ocean (0–5 m) and deep chlorophyll maximum (DCM, average depth ∼30 m). SAR11 and cyanobacterial ecotypes comprised typically more than one-third of the measured community; diversity within both was temporally variable, although a few operational taxonomic units (OTUs) were consistently more abundant. Persistent OTUs, mostly Alphaproteobacteria (SAR11 clade), Actinobacteria and Flavobacteria, tended to be abundant, in contrast to many rarer yet intermittent and ephemeral OTUs. Association networks revealed potential niches for key OTUs from SAR11, cyanobacteria, SAR86 and other common clades on the basis of robust correlations. Resilience was evident by the average communities drifting only slightly as years passed. Average Bray-Curtis similarity between any pair of dates was ∼40%, with a slight decrease over the decade and obvious near-surface seasonality; communities 8–10 years apart were slightly more different than those 1–4 years apart with the highest rate of change at 0–5 m between communities <4 years apart. The surface exhibited more pronounced seasonality than the DCM. Inter-depth Bray-Curtis similarities repeatedly decreased as the water column stratified each summer. Environmental factors were better predictors of shifts in community composition than months or elapsed time alone; yet, the best predictor was community composition at the other depth (that is, 0–5 m versus DCM).     

Age of drifting Macrocystis pyrifera (L.) C. Agardh rafts in the Southern California Bight

Macrocystis pyrifera plants that detach from the substratum float to the surface and, if they do not become entangled or wash immediately to the shore, may drift at the surface for an unknown period of time. These rafts provide habitat for a variety of coastal and pelagic fauna. The distances dispersed and the period available for species to utilize these habitats, however, depend on the longevity of the raft and methods for determining the age of rafts are unknown. A method to age drifting M. pyrifera rafts based on a change in length of blades (BL) following detachment is validated here. This technique determines the period of time since detachment and not the actual age of the plant. In general, average BL decreases from initial attached values of 50-60 to about 0 cm, when rafts sink. The rate of aging, or deterioration of BL, is related to water temperature, and sets the period a raft stays afloat. Maximal estimates of ages of rafts were between 63 and 109 days, depending on the exact method used. Their lifetime will limit the distances dispersed by kelp rafts in Southern California, and this methodology will be useful for determining the temporal patterns of abundance of fauna associated with rafts.     

The Vertical Distribution and Diversity of Marine Bacteriophage at a Station off Southern California

Sixty-two bacteriophages were isolated on eight indigenous bacteria from a Pacific Ocean station spanning 887-m vertical depth, on two occasions between 1999 and 2000. On the basis of 16S rRNA sequences, six hosts were tentatively identified to be in the genus Vibrio and the other two were closely related to Altermonas macleodii (W9a) and Pseudoalteromonas spp. (W13a). Restriction fragment length polymorphism (RFLP) analysis of phage genomes using AccI and HapI showed that 16 phages infecting host C4a (Vibrio) displayed 14 unique RFLP patterns. However, identical phages infecting host C4b, C6a, and C6b (all Vibrio) were obtained from both the surface layer and the hypoxic zone at 850 m. Most phage isolates from the second year had a different RFLP pattern but shared genetic similarity to the phages infecting the same host from the previous year based on a hybridization study using phage genome probes. Cluster analysis of RFLP patterns and hybridization results also indicated that phages infecting the same or genetically related hosts, in general, shared higher degrees of homology in spite of the diverse RFLP patterns. Pulsed field gel electrophoresis (PFGE) analysis of native viral genomes indicated a range in genome size from less than 40 to 200 kb, and the dominant band shifted up by about 5-10 kb in the deep samples compared to the shallow ones. Hybridization of phage genome probes with total viral community DNA from various depths suggests these isolates, or at least some of their genes, represent a detectable portion of the natural viral community and were distributed throughout the water column. Thus, the results of this study demonstrated that the genetic diversity of bacteriophage in the ocean is far greater than that of their bacterial hosts. However, host range may have contributed to the evolution of the diverse phage population in the marine environment.     

Energy Efficiency and Structural Change in the Netherlands, 1980–1995

International agreement has been reached to reduce greenhouse gas emissions worldwide. One important way of decoupling CO₂ emissions from economic growth is by introducing technical measures to improve energy efficiency. In this article, we assess the influence of developments in energy efficiency and economic structure on the total primary energy consumption in the Netherlands over the period 1980– 1995. We find a distinct decoupling of the economic growth and energy consumption of 1.5% per year in the 15-year analysis period. We measure (technical) changes in energy efficiency by changes in the energy consumption per physical unit of production or activity. The aggregate rate of (technical) energy-efficiency improvement was 1.4% per year over the period 1980–1995. The use of physical production indicators makes it possible to measure energy-efficiency developments without detailed surveys at a very low level of aggregation. When we look at economic structural changes over this period, we find that (i) no substantial shift took place at the level of the economic sectors that we distinguish; (ii) the most energy intensive subsectors grew much faster than the total economy; and (iii) at the subsector level, on average, a sizable decoupling of physical production and value added occurred. We conclude that structural changes, that is, changes in the composition of the economy, did not lead to a net decrease in the energy intensity of the Netherlands over the period 1980–1995.     

Blooms of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles harbor areas of the Southern California Bight, 2003–2004

Abundances of Pseudo-nitzschia spp. and concentrations of particulate domoic acid (DA) were determined in the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004. At least 1500 km² were affected by a toxic event in May/June of 2003 when some of the highest particulate DA concentrations reported for US coastal waters were measured inside the Los Angeles harbor (12.7 μg DA L⁻¹). Particulate DA levels were an order of magnitude lower in spring of 2004 (February and March), but DA concentrations per cell at several sampling stations during 2004 exceeded previously reported maxima for natural populations of Pseudo-nitzschia (mean = 24 pg DA cell⁻¹, range = 0–117 pg DA cell⁻¹). Pseudo-nitzschia australis dominated the Pseudo-nitzschia assemblage in spring 2004. Overall, DA-poisoning was implicated in >1400 mammal stranding incidents within the SCB during 2003 and 2004. Ancillary physical and chemical data obtained during our regional surveys in 2004 revealed that Pseudo-nitzschia abundances, particulate DA and cellular DA concentrations were inversely correlated with concentrations of silicic acid, nitrogen and phosphate, and to specific nutrient ratios. Particulate DA was detected in sediment traps deployed at 550 and 800 m depth during spring of 2004 (0.29–7.6 μg DA (g sediment dry weight)⁻¹). The highest DA concentration in the traps was measured within 1 week of dramatic decreases in the abundances of Pseudo-nitzschia in surface waters. To our knowledge these are the deepest sediment trap collections from which DA has been detected. Sinking of the spring Pseudo-nitzschia bloom may constitute a potentially important link between DA production in surface waters and benthic communities in the coastal ocean near Los Angeles. Our study indicates that toxic blooms of Pseudo-nitzschia are a recurring phenomenon along one of the most densely populated coastal stretches of the SCB and that the severity and magnitude of these events can be comparable to or greater than these events in other geographical regions affected by domoic acid.     

Age‐ and sex‐specific survival of California sea lions (Zalophus californianus) at San Miguel Island,California

We conducted a mark‐recapture study of California sea lions (Zalophus californianus) using pups branded on San Miguel Island, California, from 1987 to 2014, and annual resightings from 1990 to 2015. We used the Burnham model (Burnham 1993), an extension of the Cormack‐Jolly‐Seber mark‐recapture model, which includes recoveries of dead animals, to analyze age, sex, and annual patterns in survival. Generally, females had higher survival than males. For female pups, the average annual survival was 0.600 and for male pups it was 0.574. Yearling survival was 0.758 and 0.757 for females and males, respectively. Peak annual survival was at age 5 and was 0.952 for females and 0.931 for males. Pups with larger mass at branding had higher survival as pups and yearlings, but the effect was relative within each cohort because of large between‐cohort variability in survival. Annual variability in sea surface temperature (SST) affected survival. For each 1°C increase in SST, the odds of survival decreased by nearly 50% for pups and yearlings; negative SST anomalies yielded higher survival. Annual variation in male survival was partly explained by leptospirosis outbreaks. Our study provides a unique view of one demographic parameter that contributed to the successful recovery of the California sea lion population.     

Estimating ocean primary production from satellite chlorophyll. Introduction to regional differences and statistics for the Southern California Bight

The prospect of estimating primary production (II, mg C m^–2d^–1)from chlorophyll pigment concentrations (C_k, mg m^–3 nearthe ocean surface is appealing, now that chlorophyll concentrationscan be extracted from satellite images. Earlier work has showna proportionality between II and C_k (II     

Temperature record in the oxygen stable isotopes of Pacific sardine otoliths: Experimental vs. wild stocks from the Southern California Bight

Pacific sardines (Sardinops sagax) are commercially fished in Canada, USA, and Mexico along approximately 5000 km of coastal waters that experience a wide range of temperatures. Trinational management of the species can be problematic because the connectivity between spawning, recruitment, stock residency, and migration in some years may not be well predicted. Oxygen isotopic value of otoliths (δ¹⁸O_otolith) has been used to infer stock residency and movement of fish populations within regions, but few studies have used laboratory data to establish a predictive temperature model to validate δ¹⁸O_otolith values of wild fish. We conducted a growth experiment with juveniles at different temperatures using Southern California Bight (SCB) seawater to test the assumption that Pacific sardine otoliths accurately record environmental water temperature in the presence of constant salinity. Sardine δ¹⁸O_otolith values were significantly and negatively correlated with temperature according to the linear model:

δ¹⁸Ootolith(‰)−δ¹⁸Owater(‰)=−0.132(±0.003 SE)×Temperature(°C)+2.455(±0.043 SE)