Recent estimates based on shipboard echosounders suggest that 50% or more of global fish biomass may reside in the mesopelagic zone (depths of ∼200-1000 m). Nonetheless, little is known about the acoustic target strengths (TS) of mesopelagic animals because ship-based measurements cannot resolve individual targets. As a result, biomass estimates of mesopelagic organisms are poorly constrained. Using an instrumented tow-body, broadband (18-90 kHz) TS measurements were obtained at depths from 70 to 850 m. A comparison between TS measurements at-depth and values used in a recent global estimate of mesopelagic biomass suggests lower target densities at most depths.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1121/10.0001745 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Observations of dissolved cadmium (dCd) and phosphate (PO) suggest an unexplained loss of dCd to the particulate phase in tropical oxyclines. Here, we compile existing observations of particulate Cd and phosphorus (P), and present new data from the US GEOTRACES GP15 Pacific Meridional Transect to examine this phenomenon from a particulate Cd perspective. We use a simple algorithm to reproduce station depth profiles of particulate Cd and P via regeneration and possible subsurface accumulation.
View Article and Find Full Text PDFThe Controls Over Mesopelagic Interior Carbon Storage (COMICS) cruise DY086 took place aboard the RRS Discovery in the South Atlantic during November and December, 2017. Physical, chemical, biogeochemical and biological data were collected during three visits to ocean observatory station P3, off the coast of South Georgia, during an austral spring bloom. A diverse range of equipment including CTD-rosette, Acoustic Doppler Current Profiler (ADCP), net deployments, marine snow catchers (MSCs), Stand Alone Pump System (SAPS) and PELAGRA Sediment Traps were used to produce a comprehensive, high-quality dataset.
View Article and Find Full Text PDFStrandings and at sea observations reveal the canary archipelago as an important habitat for pygmy and dwarf sperm whale.
Adv Mar Biol
November 2024
Veterinary Histology and Pathology, Atlantic Center for Cetacean Research, University Institute of Animal Health and Food Safety (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, Canary Islands, Spain.
Article Synopsis
- Cetaceans, particularly Kogia species, play a vital role in marine ecosystems as top predators, but they face significant threats from human activities in the Macaronesian region.
- A study of Kogia whales stranded and sighted in the Canary Islands over several decades revealed 111 stranding events and 36 sightings, highlighting the prevalence of K. breviceps and K. sima in these waters.
- These findings provide crucial baseline data for future conservation efforts and emphasize the need for better understanding and protection of these elusive cetaceans.
Role of Storage Lipids in Vertical Migrations of Beaked Redfish Sebastes mentella in the North Atlantic.
Dokl Biol Sci
November 2024
Institute of Biology, Karelian Research Center, Russian Academy of Sciences, Petrozavodsk, Russia.
The contents of main classes of storage lipids (triacylglycerols, cholesterol esters, and waxes) in muscles and the liver of the beaked redfish Sebastes mentella were studied across the depth gradient and in different areas of the North Atlantic. Significant differences in storage lipid contents were observed between fish from different fishing horizons. The depth-dependent changes in lipids in fish tissues and organs were assumed to indicate that triacylglycerols (TAGs), cholesterol esters (CEs), and waxes are utilized as energy sources, in particular, to maintain the buoyancy during vertical migration.
View Article and Find Full Text PDFUrea assimilation and oxidation support activity of phylogenetically diverse microbial communities of the dark ocean.
ISME J
January 2024
Department of Earth System Science, Stanford University, 473 Via Ortega, Stanford, CA 94305, United States.
Urea is hypothesized to be an important source of nitrogen and chemical energy to microorganisms in the deep sea; however, direct evidence for urea use below the epipelagic ocean is lacking. Here, we explore urea utilization from 50 to 4000 meters depth in the northeastern Pacific Ocean using metagenomics, nitrification rates, and single-cell stable-isotope-uptake measurements with nanoscale secondary ion mass spectrometry. We find that on average 25% of deep-sea cells assimilated urea-derived N (60% of detectably active cells), and that cell-specific nitrogen-incorporation rates from urea were higher than that from ammonium.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!