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Three morphotypes-purple, tan, and white-of an irregular echinoid of the genus Echinocrepis are commonly observed in the deep North Pacific Ocean. Mitochondrial (mt) 16S DNA and cytochrome c oxidase subunit I ( COI) DNA sequences were amplified from gonadal tissue samples from specimens of each morphotype. These portions of the mitochondrial genome are commonly used in species barcoding, and their similarities were compared and placed in 95% connection limit parsimony networks. All three morphotypes have similar 16S mtDNA and COI mtDNA sequences, and are thus likely representatives of the same species, Echinocrepis rostrata. Specimens of the white morphotype were smaller than the specimens of the other two morphotypes, had less gonad tissue, and had a different body shape, suggesting that it represents the juvenile form of E. rostrata. Resolving the three morphotypes into one species simplifies the identification of E. rostrata from photographs and leads to a greater understanding of the life history and reproductive cycle of a species vital to deep-sea bioturbation and carbon sequestration. [ABSTRACT FROM AUTHOR]

We hypothesized that seasonal and interannual climate-mediated changes in particulate organic carbon (POC) flux would affect bioturbation and ultimately the sequestration of organic carbon in the deep sea. An 18-yr timeseries photographic record from 4100-m depth in the northeast Pacific Ocean showed increased abundance of Echinocrepis rostrata, a common epibenthic echinoid and bioturbator, since the late 1990s. Abundance, size, and speed data were used to estimate bioturbation potential to track long-term changes in the volume of sediment disturbed by E. rostrata. There was no secular increase in E. rostrata bioturbation over 18 yr despite increased population size, although periodic variations in bioturbation were significantly correlated with POC flux. Expected changes in POC flux and bioturbation rates due to climate variation could lead to altered rates of carbon sequestration in deep-sea sediments, affecting the global carbon cycle. [ABSTRACT FROM AUTHOR]

A deep-sea time-lapse camera and several temperature probes were deployed on the Gulf of Mexico continental shelf at a biological community associated with a gas hydrate outcropping to study topographic and hydrologic changes over time. The deployment site, Bush Hill (GC-185), is located at 27°47.5′ N and 91°15.0′ W at depths of ∼540 m. The digital camera recorded one still image every 6 h for July-October in 2001, every 2 h for the month of June 2002, and every 6 h for the month of July 2002. Temperature probes were in place at the site for the entire experimental period. The data recovered provide a record of processes that occur at gas hydrate mounds. Sediment resuspension over the mound causes significant variation in luminosity of the time-lapse photographs. A marked diurnal pattern can be seen in the temperature and luminosity records. No major change in shape or size of the gas hydrate outcrop at this site was observed during this study. Stable topography of the gas hydrate mound, combined with high bacterial activity and sediment turnover, appears to focus biological activity in the mound area. Frequency and recurrence of sediment resuspension indicate that short-term change in the depth and distribution of surface sediments is a feature of the benthos at the site. Because the sediment interface is a critical environment for hydrocarbon oxidation and chemosynthesis, short-term variability and heterogeneity may be important characteristics of these settings. [ABSTRACT FROM AUTHOR]

Animal migrations are of global ecological significance, providing mechanisms for the transport of nutrients and energy between distant locations. In much of the deep sea (>200 m water depth), the export of nutrients from the surface ocean provides a crucial but seasonally variable energy source to seafloor ecosystems. Seasonal faunal migrations have been hypothesized to occur on the deep seafloor as a result, but have not been documented.Here, we analyse a 7.5‐year record of photographic data from the Deep‐ocean Environmental Long‐term Observatory Systems seafloor observatories to determine whether there was evidence of seasonal (intra‐annual) migratory behaviours in a deep‐sea fish assemblage on the West African margin and, if so, identify potential cues for the behaviour.Our findings demonstrate a correlation between intra‐annual changes in demersal fish abundance at 1,400 m depth and satellite‐derived estimates of primary production off the coast of Angola. Highest fish abundances were observed in late November with a smaller peak in June, occurring approximately 4 months after corresponding peaks in primary production.Observed changes in fish abundance occurred too rapidly to be explained by recruitment or mortality, and must therefore have a behavioural driver. Given the recurrent patterns observed, and the established importance of bottom‐up trophic structuring in deep‐sea ecosystems, we hypothesize that a large fraction of the fish assemblage may conduct seasonal migrations in this region, and propose seasonal variability in surface ocean primary production as a plausible cause. Such trophic control could lead to changes in the abundance of fishes across the seafloor by affecting secondary production of prey species and/or carrion availability for example.In summary, we present the first evidence for seasonally recurring patterns in deep‐sea demersal fish abundances over a 7‐year period, and demonstrate a previously unobserved level of dynamism in the deep sea, potentially mirroring the great migrations so well characterized in terrestrial systems. [ABSTRACT FROM AUTHOR]

The Ocean Observatories Initiative (OOI) is an integrated suite of instrumented platforms and discrete instruments that measure physical, chemical, geological, and biological properties from the seafloor to the sea surface. The OOI provides data to address large-scale scientific challenges such as coastal ocean dynamics, climate and ecosystem health, the global carbon cycle, and linkages among seafloor volcanism and life. The OOI Cyberinfrastructure currently serves over 250 terabytes of data from the arrays. These data are freely available to users worldwide, changing the way scientists and the broader community interact with the ocean, and permitting ocean research and inquiry at scales of centimeters to kilometers and seconds to decades. [ABSTRACT FROM AUTHOR]

From mid-May to August 2011, extreme runoff in the Columbia River ranged from 14,000 to over 17,000 m3/s, more than two standard deviations above the mean for this period. The extreme runoff was the direct result of both melting of anomalously high snowpack and rainfall associated with the 2010-2011 La Niña. The effects of this increased freshwater discharge were observed off Newport, Oregon, 180 km south of the Columbia River mouth. Salinity values as low as 22, nine standard deviations below the climatological value for this period, were registered at the mid-shelf. Using a network of ocean observing sensors and platforms, it was possible to capture the onshore advection of the Columbia River plume from the mid-shelf, 20 km offshore, to the coast and eventually into Yaquina Bay (Newport) during a sustained wind reversal event. Increased freshwater delivery can influence coastal ocean ecosystems and delivery of offshore, river-influenced water may influence estuarine biogeochemistry. [ABSTRACT FROM AUTHOR]