Observed transmissions and ocean-ice-acoustic coupled modelling in the Beaufort Sea.

An ocean-ice-acoustic coupled model is configured for the Beaufort Sea. The model uses outputs from a data assimilating global scale ice-ocean-atmosphere forecast to drive a bimodal roughness algorithm for generating a realistic ice canopy. The resulting range-dependent ice cover obeys observed roughness, keel number density, depth, and slope, and floe size statistics. The ice is inserted into a parabolic equation acoustic propagation model as a near-zero impedance fluid layer along with a model defined range-dependent sound speed profile. Year-long observations of transmissions at 35 Hz from the Coordinated Arctic Acoustic Thermometry Experiment and 925 Hz from the Arctic Mobile Observing System source were recorded over the winter of 2019-2020 on a free-drifting, eight-element vertical line array designed to vertically span the Beaufort duct. The ocean-ice-acoustic coupled model predicts receive levels that reasonably agree with the measurements over propagation ranges of 30-800 km. At 925 Hz, seasonal and sub-seasonal ocean and ice driven variations of propagation loss are captured in the data and reproduced in the model.

Gray whale density during seismic surveys near their Sakhalin feeding ground.

Oil and gas development off northeastern Sakhalin Island, Russia, has exposed the western gray whale population on their summer-fall foraging grounds to a range of anthropogenic activities, such as pile driving, dredging, pipeline installation, and seismic surveys. In 2015, the number of seismic surveys within a feeding season surpassed the level of the number and duration of previous seismic survey activities known to have occurred close to the gray whales' feeding ground, with the potential to cause disturbance to their feeding activity. To examine the extent that gray whales were potentially avoiding areas when exposed to seismic and vessel sounds, shore-based teams monitored the abundance and distribution of gray whales from 13 stations that encompassed the known nearshore feeding area. Gray whale density was examined in relation to natural (spatial, temporal, and prey energy) and anthropogenic (cumulative sound exposure from vessel and seismic sounds) explanatory variables using Generalized Additive Models (GAM). Distance from shore, water depth, date, and northing explained a significant amount of variation in gray whale densities. Prey energy from crustaceans, specifically amphipods, isopods, and cumaceans also significantly influenced gray whale densities in the nearshore feeding area. Increasing cumulative exposure to vessel and seismic sounds resulted in both a short- and longer-term decline in gray whale density in an area. This study provides further insights about western gray whale responses to anthropogenic activity in proximity to and within the nearshore feeding area. As the frequency of seismic surveys and other non-oil and gas anthropogenic activity are expected to increase off Sakhalin Island, it is critical to continue to monitor and assess potential impacts on this endangered population of gray whales.

Acoustic monitoring and analyses of air gun, pile driving, vessel, and ambient sounds during the 2015 seismic surveys on the Sakhalin shelf.

During the summer of 2015, four 4D seismic surveys were conducted on the northeastern Sakhalin shelf near the feeding grounds of the Korean-Okhotsk (western) gray whale (Eschrichtius robustus) population. In addition to the seismic surveys, onshore pile driving activities and vessel operations occurred. Forty autonomous underwater acoustic recorders provided data in the 2 Hz to15 kHz frequency band. Recordings were analyzed to evaluate the characteristics of impulses propagating from the seismic sources. Acoustic metrics analyzed comprised peak sound pressure level (PK), mean square sound pressure level (SPL), sound exposure level (SEL), T100%, T90% (the time intervals that contain the full and 90% of the energy of the impulse), and kurtosis. The impulses analyzed differed significantly due to the variability and complexity of propagation in the shallow water of the northeast Sakhalin shelf. At larger ranges, a seismic precursor propagated in the seabed ahead of the acoustic impulse, and the impulses often interfered with each other, complicating analyses. Additional processing of recordings allowed evaluation and documentation of relevant metrics for pile driving, vessel sounds, and ambient background levels. The computed metrics were used to calibrate acoustic models, generating time resolved estimates of the acoustic levels from seismic surveys, pile driving, and vessel operations on a gray whale distribution grid and along observed gray whale tracks. This paper describes the development of the metrics and the calibrated acoustic models, both of which will be used in work quantifying gray whale behavioral and distribution responses to underwater sounds and to determine whether these observed responses have the potential to impact important parameters at the population level (e.g., reproductive success).

Western gray whale behavioral response to seismic surveys during their foraging season.

Gray whales utilizing their foraging grounds off northeastern Sakhalin Island, Russia, have been increasingly exposed to anthropogenic activities related to oil and gas development over the past two decades. In 2015, four seismic vessels, contracted by two operators, conducted surveys near and within the gray whale feeding grounds. Mitigation and monitoring plans were developed prior to the survey and implemented in the field, with real-time data transfers to assist the implementation of measures aimed at minimizing impacts of acoustic exposure. This study examined the behavioral response of gray whales relative to vessel proximities and sounds generated during seismic exploration. Five shore-based teams monitored gray whale behavior from 1 June to 30 September using theodolite tracking and focal follow methodologies. Behavioral data were combined with acoustic and benthic information from studies conducted during the same period. A total of 1270 tracks (mean duration = 0.9 h) and 401 focal follows (1.1 h) were collected with gray whales exposed to sounds ranging from 59 to 172 dB re 1 µPa2 SPL. Mixed models were used to examine 13 movement and 10 respiration response variables relative to "natural," acoustic, and non-acoustic explanatory variables. Water depth and behavioral state were the largest predictors of gray whale movement and respiration patterns. As vessels approached whales with increasing seismic/vessel sound exposure levels and decreasing distances, several gray whale movement and respiration response variables significantly changed (increasing speed, directionality, surface time, respiration intervals, etc.). Although the mitigation measures employed could have reduced larger/long-term responses and sensitization to the seismic activities, this study illustrates that mitigation measures did not eliminate behavioral responses, at least in the short-term, of feeding gray whales to the activities.

Real-time acoustic monitoring with telemetry to mitigate potential effects of seismic survey sounds on marine mammals: a case study offshore Sakhalin Island.

Exxon Neftegas Ltd. (ENL) carried out three 4D seismic surveys during the summer of 2015. Seismic operations in two of these fields (Odoptu and Chayvo) ensonified the nearshore feeding area of Korean-Okhotsk (western) gray whales (Eschrichtius robustus), potentially disturbing feeding activities. Following model-based optimization of the source design to minimize its lateral acoustic footprint, pre-season modeling was used to compute the acoustic exposure along each survey line. Real-time acoustic data facilitated implementation of mitigation measures aimed to minimize disturbance of whales. Acoustic data originated from underwater recorders deployed on the seafloor. Two complementary approaches were used to transmit recorded sound data to a computer housed at the Central Post (CP), where decisions regarding mitigation shut downs were made. In the first approach, a limited bandwidth (2-2000 Hz) sampling of the data was transmitted via cable to a surface buoy, which relayed these data to a shore station up to 15 km away via digital VHF telemetry. At the shore station, acoustic impulses from the seismic surveys were processed to compute impulse characteristics in the form of estimates of sound exposure level and peak sound pressure level, as well as one-minute-average 1/3-octave power spectral density coefficients, which were then transmitted to the CP via the internet. In the second, the pulse characteristics were computed through algorithms running on an onboard processor in each recorder's surface buoy and sent directly to the CP computer via an Iridium satellite uplink. Both methods of data transfer proved viable, but Iridium transmission achieved the goal without the need for any shore based relay stations and is therefore more operationally efficient than VHF transmission. At the CP, analysts used the real-time acoustic data to calibrate and adjust the output of pre-season acoustical model runs. The acoustic footprint for the active seismic source, advancing synchronously with the motion of the seismic vessel and changing as the sound propagation environment changed, was computed from the calibrated and adjusted model output and integrated through the software Pythagoras with locations of gray whales provided by shore-based observers. This enabled analysts to require air gun array shutdowns before whales were exposed to mean square sound pressure levels greater than the behavioral response threshold of 163 dB re 1 µPa2. The method described here provides a realistic means of mitigating the possible effects of air guns at a behavioral response level, whereas most seismic surveys rely on pre-established mitigation radii to manage the risk of injury to a whale.

Increased Serum Parathyroid Hormone, Osteocalcin and Alkaline Phosphatase Are Associated with a Long-Term Adverse Cardiovascular Outcome after Coronary Artery Bypass Graft Surgery.

Despite the fact that an association of osteopoenia/osteoporosis with elevated risk of coronary artery calcification (CAC) and coronary atherosclerosis (CA) is well-established, it remains unclear whether bone turnover markers can be employed in long-term prognostication of such patients. Here we measured serum calcium, phosphate, calcitonin, parathyroid hormone (PTH), osteoprotegerin, osteocalcin, osteopontin, alkaline phosphatase and its bone isoenzyme, subsequently correlating them with an adverse cardiovascular outcome after 3 years of follow-up. The extent of brachiocephalic artery stenosis, CA, or CAC, as well as prevalence of osteopoenia/osteoporosis before the coronary artery bypass graft (CABG) surgery, did not differ between outcome groups, suggesting that subtle molecular mechanisms might be involved in determining the outcome rather than clinical or subclinical disease. After stepwise logistic regression, serum osteocalcin > 26.8 ng/mL and PTH > 49.1 pg/mL were independent predictors of an adverse outcome. Serum ionised calcium correlated with multivessel coronary artery disease; moreover, patients with severe CA (SYNTAX score > 21) had higher serum ionised calcium than those with mild CA. Likewise, serum alkaline phosphatase was associated with severe CA and CAC (Agatston score > 400). In conclusion, serum PTH, osteocalcin, and alkaline phosphatase are associated with an adverse cardiovascular outcome 3 years after CABG surgery regardless of osteopoenia/osteoporosis, coronary/peripheral atherosclerosis, and CAC.

Serum neutrophil gelatinase-associated lipocalin has an advantage over serum cystatin C and glomerular filtration rate in prediction of adverse cardiovascular outcome in patients with ST-segment elevation myocardial infarction.

BACKGROUND: The aim of this study was to assess significance of serum neutrophil gelatinase-associated lipocalin (sNGAL) and cystatin C (sCC) in prediction of adverse cardiovascular outcome after ST-segment elevation myocardial infarction (STEMI). METHODS: We recruited 357 consecutive patients who were admitted to the hospital within 24 h after onset of STEMI. On the 1st and 12th-14th day after hospital admission, we measured levels of sNGAL and sCC. We also determined presence of renal dysfunction (RD), defined as glomerular filtration rate < 60 mL/min/1.73 m2. After 3 years of follow-up, we performed a logistic regression and assessed the value of RD, sNGAL, and sCC in prediction of combined endpoint, defined as cardiovascular death or any cardiovascular complication. RESULTS: RD, sCC level ≥ 1.9 mg/L, and sNGAL level ≥ 1.25 ng/mL on the 12th-14th day of hospitalization were associated with a 1.6-fold, 1.9-fold, and 2.9-fold higher risk of adverse cardiovascular outcome, respectively. Area under the ROC curve was the highest for the model based on sNGAL level compared to the models based on sCC level or RD presence. CONCLUSIONS: Measurement of sNGAL level in patients with STEMI on the 12th-14th day after hospital admission may improve prediction of adverse cardiovascular outcome.

Interleukin-12 serum level has prognostic value in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: The study aimed to evaluate whether serum inflammatory markers have prognostic value in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: The role of cytokine-driven inflammation in the development of postdischarge complications after STEMI is obscured. METHODS: We recruited 214 patients who were admitted within 24 h of STEMI onset to our Institute. IL-1α, -6, -8, -10, -12, TNF-α, and CRP serum levels were measured on the 10-14th day after STEMI onset. RESULTS: Serum levels of IL-12, TNF-α, and CRP were significantly higher in patients with 3 affected coronary arteries compared to those with 1 affected coronary artery. However, only Killip class II-IV at admission and IL-12 serum level ≥90.0 pg/mL were defined as statistically significant predictors of adverse outcome after 1 year of follow-up. CONCLUSION: IL-12 serum level may be suggested as a candidate prognostic marker if measured 10-14 days after STEMI onset.

The prognostic value of peripheral artery diseases in patients with ST-segment elevation myocardial infarction.

HYPOTHESIS: To evaluate the clinical and prognostic role of haemodynamically insignificant stenosis of the extracranial arteries (ECA) and lower extremity arteries (LEA) among patients with ST-segment elevation myocardial infarction (STEMI). PATIENTS AND METHODS: The study sample consisted of 423 patients with STEMI who were consecutively admitted to the Kemerovo Cardiological Centre. RESULTS: The prevalence of polyvascular diseases (PVD), as defined by an increased intima-media thickness (IMT) of the common carotid artery or by stenosis of the ECA or LEA, was 95%. Among patients with ECA or LEA, the case fatality rate of those with stenosis with occlusion of less than 30% of the vessel lumen was 5.7%, whereas the case fatality rate among patients with stenosis with occlusion of more than 30% of the vessel lumen was 15.1% (χ(2) = 13.68, P = 0.003). Using the GRACE score model, together with the determination of additional factors (congestive heart failure, PVD, prior stroke, and smoking status), we developed an improved model (KemScore) for death risk stratification for a 12-month period. The value of the AUC for our model (KemScore) was 0.83 (95% CI = 0.76-0.90), which was significantly higher than the initial GRACE score value of 0.71 (95% CI = 0.63-0.79).

Tracking of Pacific walruses in the Chukchi Sea using a single hydrophone.

The vocal repertoire of Pacific walruses includes underwater sound pulses referred to as knocks and bell-like calls. An extended acoustic monitoring program was performed in summer 2007 over a large region of the eastern Chukchi Sea using autonomous seabed-mounted acoustic recorders. Walrus knocks were identified in many of the recordings and most of these sounds included multiple bottom and surface reflected signals. This paper investigates the use of a localization technique based on relative multipath arrival times (RMATs) for potential behavior studies. First, knocks are detected using a semi-automated kurtosis-based algorithm. Then RMATs are matched to values predicted by a ray-tracing model. Walrus tracks with vertical and horizontal movements were obtained. The tracks included repeated dives between 4.0 m and 15.5 m depth and a deep dive to the sea bottom (53 m). Depths at which bell-like sounds are produced, average knock production rate and source levels estimates of the knocks were determined. Bell sounds were produced at all depths throughout the dives. Average knock production rates varied from 59 to 75 knocks/min. Average source level of the knocks was estimated to 177.6 ± 7.5 dB re 1 µPa peak @ 1 m.