Distribution and Abundance of Phytoplankton, Zooplankton, Ichthyoplankton, and Micronekton in the Deepwater Gulf of Mexico

Expeditions in the 1960s and 1970s are the basis for the general paradigm that standing stocks and productivity of phytoplankton are both low ( \u3c0.1 mg chl·m-3; \u3c150 mg C.m-2·d-1) seaward of the shelf-slope break in the Gulf of Mexico. The present review supports this description of the mean (stable) state but also shows hot spots in primary production (\u3e2 g C·m-2·d-1) occur when/where nutrient availability is locally enhanced seaward of the shelf-slope break. Recent collections with Bongo and MOCNESS nets, midwater trawls, and bioacoustic surveys of the Loop Current and associated cyclonic and anticyclonic eddies in the Gulf of Mexico show that these deepwater hot spots have higher stocks of zooplankton and micronekton as well. The local aggregations ranged in size from coarse- to meso- spatial scales (10s to 100s of kilometers) though locations of such oases were spatially variable along the continental margin

Zooplankton and Micronekton in Cyclones and Anticyclones in the Northeast Gulf of Mexico

Two cruises were made to the northeast Gulf of Mexico in October 1996 and August 1997. The main objectives of the cruises were to survey cetacean and seabird populations and describe their hydrographic and biological environments. An additional objective was to characterize cetacean and seabird habitats in terms of food resources. During both cruises a cyclone and an anticyclone were sampled as well as the confluence region between them. Zooplankton and micronekton were sampled both directly with nets and indirectly with a 153-kHz acoustic Doppler current profiler. Within cruises, zooplankton and micronekton biomass was higher in cyclones than in anticyclones. Biomass within the confluence was either highest or intermediate for both cruises. Between cruises, within features, August 1997 biomass was significantly higher than October 1996 biomass

Spatio-temporal distribution of euphausiids: an important component to understanding ecosystem processes in the Gulf of Alaska and eastern Bering Sea

Abstract Euphausiids (principally Thysanoessa spp.) are found in high abundance in both the eastern Bering Sea (EBS) and the Gulf of Alaska (GOA). They are an important part of these cold-water coastal and pelagic ecosystems as a key prey item for many species, including marine mammals, seabirds, and fish, forming an ecological link between primary production and higher trophic levels. Acoustic-trawl (AT) survey methods provide a means of monitoring euphausiid abundance and distribution over a large spatial scale. Four years of AT and bottom-trawl survey data (2003, 2005, 2011, and 2013) were available from consistently sampled areas around Kodiak Island, including Shelikof Strait, Barnabas Trough, and Chiniak Trough. We identified euphausiid backscatter using relative frequency response and targeted trawling, and created an annual index of abundance for euphausiids. This index has broad application, including use in the stock assessments for GOA walleye pollock (Gadus chalcogrammus) and other species, as an ecosystem indicator, and to inform ecological research. We then used generalized additive models (GAMs) to examine the relationship between relative euphausiid abundance and potential predictors, including pollock abundance, temperature, bottom depth, and primary production. Model results were compared with an updated GAM of euphausiid abundance from the EBS to determine if the factors driving abundance and distribution were consistent between both systems. Temperature was not a strong predictor of euphausiid abundance in the GOA as in the EBS; warmer temperatures and lack of seasonal ice cover in the GOA may be a key difference between these ecosystems. Pollock abundance was significant in both the GOA and the EBS models, but was not a strongly negative predictor of euphausiid abundance in either system, a result not consistent with top-down control of euphausiid abundance

Temporal shifts in seabird populations and spatial coherence with prey in the southeastern Bering Sea

The Bering Sea is a highly productive ecosystem with abundant prey populations in the summer that support some of the largest seabird colonies in the Northern Hemisphere. In the fall, the Bering Sea is used by large numbers of migrants and post-breeding seabirds. We used over 22000 km of vessel-based surveys carried out during summer (June to July) and fall (late August to October) from 2008 to 2010 over the southeast Bering Sea to examine annual and seasonal changes in seabird communities and spatial relationships with concurrently sampled prey. Deep-diving murres Uria spp., shallow-diving shearwaters Ardenna spp., and surface-foraging northern fulmars Fulmarus glacialis and kittiwakes Rissa spp. dominated summer and fall seabird communities. Seabird densities in summer were generally less than half of fall densities and species richness was lower in summer than in fall. Summer seabird densities had high interannual variation (highest in 2009), whereas fall densities varied little among years. Seabirds were more spatially clustered around breeding colonies and the outer continental shelf in the summer and then dispersed throughout the middle and inner shelf in fall. In summer, the abundance of age-1 walleye pollock Gadus chalcogrammus along with spatial (latitude and longitude) and temporal (year) variables best explained broad-scale seabird distribution. In contrast, seabirds in fall had weaker associations with spatial and temporal variables and stronger associations with different prey species or groups. Our results demonstrate seasonal shifts in the distribution and foraging patterns of seabirds in the southeastern Bering Sea with a greater dependence on prey occurring over the middle and inner shelf in fall.Keywords: Spatial models, Seabird, Seasonal patterns, Krill, Forage fis

The AURORA Study: A Longitudinal, Multimodal Library of Brain Biology and Function after Traumatic Stress Exposure

Adverse posttraumatic neuropsychiatric sequelae (APNS) are common among civilian trauma survivors and military veterans. These APNS, as traditionally classified, include posttraumatic stress, postconcussion syndrome, depression, and regional or widespread pain. Traditional classifications have come to hamper scientific progress because they artificially fragment APNS into siloed, syndromic diagnoses unmoored to discrete components of brain functioning and studied in isolation. These limitations in classification and ontology slow the discovery of pathophysiologic mechanisms, biobehavioral markers, risk prediction tools, and preventive/treatment interventions. Progress in overcoming these limitations has been challenging because such progress would require studies that both evaluate a broad spectrum of posttraumatic sequelae (to overcome fragmentation) and also perform in-depth biobehavioral evaluation (to index sequelae to domains of brain function). This article summarizes the methods of the Advancing Understanding of RecOvery afteR traumA (AURORA) Study. AURORA conducts a large-scale (n = 5000 target sample) in-depth assessment of APNS development using a state-of-the-art battery of self-report, neurocognitive, physiologic, digital phenotyping, psychophysical, neuroimaging, and genomic assessments, beginning in the early aftermath of trauma and continuing for 1 year. The goals of AURORA are to achieve improved phenotypes, prediction tools, and understanding of molecular mechanisms to inform the future development and testing of preventive and treatment interventions

The Mid-infrared Instrument for JWST and Its In-flight Performance

The Mid-Infrared Instrument (MIRI) extends the reach of the James Webb Space Telescope (JWST) to 28.5 μm. It provides subarcsecond-resolution imaging, high sensitivity coronagraphy, and spectroscopy at resolutions of λ/Δλ ∼ 100-3500, with the high-resolution mode employing an integral field unit to provide spatial data cubes. The resulting broad suite of capabilities will enable huge advances in studies over this wavelength range. This overview describes the history of acquiring this capability for JWST. It discusses the basic attributes of the instrument optics, the detector arrays, and the cryocooler that keeps everything at approximately 7 K. It gives a short description of the data pipeline and of the instrument performance demonstrated during JWST commissioning. The bottom line is that the telescope and MIRI are both operating to the standards set by pre-launch predictions, and all of the MIRI capabilities are operating at, or even a bit better than, the level that had been expected. The paper is also designed to act as a roadmap to more detailed papers on different aspects of MIRI

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Combining data from bottom trawl and acoustic surveys to estimate an index of abundance for semipelagic species.

Fishery-independent surveys are useful for estimating abundance of fish populations and their spatial distribution. It is necessary in the case of semipelagic species to perform acoustic-trawl (AT) and bottom-trawl (BT) surveys to assure that sampling encompasses both midwater and demersal components of the population. Abundance estimates from both survey types are negatively biased because of the blind zones associated with fish vertical distribution. These biases can vary spatially and temporally, resulting in confounded trends and additional variation in abundance estimates. To improve abundance estimates for semipelagic species we propose a new method for combining BT and AT survey data using environmental variables to predict the vertical overlap. On an example of pollock AT and BT surveys in the eastern Bering Sea we show that combined estimates provide more reliable whole water column and spatial distribution estimates than either survey can by itself. Although the combined estimates are still relative they account for the uncertainty in the bias ratio between two survey methods and uncertainty associated with the extent of the water column sampled by both surveys. Our method of combining BT and AT data can be extended to other semipelagic species.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Timing of ice retreat alters seabird abundances and distributions in the southeast Bering Sea

Timing of spring sea-ice retreat shapes the southeast Bering Sea food web. We compared summer seabird densities and average bathymetry depth distributions between years with early (typically warm) and late (typically cold) ice retreat. Averaged over all seabird species, densities in early-ice-retreat-years were 10.1% (95% CI: 1.1-47.9%) of that in late-ice-retreat-years. In early-ice-retreat-years, surface-foraging species had increased numbers over the middle shelf (50-150 m) and reduced numbers over the shelf slope (200-500 m). Pursuit-diving seabirds showed a less clear trend. Euphausiids and the copepod Calanus marshallae/glacialis were 2.4 and 18.1 times less abundant in early-ice-retreat-years, respectively, whereas age-0 walleye pollock Gadus chalcogrammus near-surface densities were 51× higher in early-ice-retreat-years. Our results suggest a mechanistic understanding of how present and future changes in sea-ice-retreat timing may affect top predators like seabirds in the southeastern Bering Sea