1,721,025 research outputs found
Shifts in deep-sea community structure linked to climate and food supply
No full textA major change in the community structure of the dominant epibenthic megafauna was observed at 4100 meters depth in the northeast Pacific and was synchronous to a major El Niño/La Niña event that occurred between 1997 and 1999. Photographic abundance estimates of epibenthic megafauna from 1989 to 2002 show that two taxa decreased in abundance after 1998 by 2 to 3 orders of magnitude, whereas several other species increased in abundance by 1 to 2 orders of magnitude. These faunal changes are correlated to climate fluctuations dominated by El Niño/La Niña. Megafauna even in remote marine areas appear to be affected by contemporary climatic fluctuations. Such faunal changes highlight the importance of an adequate temporal perspective in describing biodiversity, ecology, and anthropogenic impacts in deep-sea communities
Temporal changes in deep-sea sponge populations are correlated to changes in surface climate and food supply
No full textDensity and average size of two species of abyssal sponges were analyzed at Station M (?4100 m depth) over an 18-year time-series (1989–2006) using camera sled transects. Both sponge taxa share a similar plate-like morphology despite being within different families, and both showed similar variations in density and average body size over time, suggesting that the same factors may control the demographics of both species. Peaks in significant cross correlations between increases in particulate organic carbon flux and corresponding increases in sponge density occurred with a time lag of 13 months. Sponge density also fluctuated with changes in two climate indices: the NOI with a time lag of 18 months and NPGO with a time lag of 15 months. The results support previous suggestions that increased particulate organic carbon flux may induce recruitment or regeneration in deep-sea sponges. It is unknown whether the appearance of young individuals results from recruitment, regeneration, or both, but the population responses to seasonal and inter-annual changes in food supply demonstrate that sponge populations are dynamic and are capable of responding to inter-annual changes despite being sessile and presumably slow-growing
Connections between climate, food limitation, and carbon cycling in abyssal sediment communities
No full textDiverse faunal groups inhabit deep-sea sediments over much of Earth's surface, but our understanding of how interannual-scale climate variation alters sediment community components and biogeochemical processes remains limited. The vast majority of deep-sea communities depend on a particulate organic carbon food supply that sinks from photosynthetically active surface waters. Variations in food supply depend, in part, on surface climate conditions. Proposed ocean iron fertilization efforts are also intended to alter surface production and carbon export from surface waters. Understanding the ecology of the abyssal sediment community and constituent metazoan macrofauna is important because they influence carbon and nutrient cycle processes at the seafloor through remineralization, bioturbation, and burial of the sunken material. Results from a 10-year study in the abyssal NE Pacific found that climate-driven variations in food availability were linked to total metazoan macrofauna abundance, phyla composition, rank-abundance distributions, and remineralization over seasonal and interannual scales. The long-term analysis suggests that broad biogeographic patterns in deep-sea macrofauna community structure can change over contemporary timescales with changes in surface ocean conditions and provides significant evidence that sediment community parameters can be estimated from atmospheric and upper-ocean conditions. These apparent links between climate, the upper ocean, and deep-sea biogeochemistry need to be considered in determining the long-term carbon storage capacity of the ocean
Rossellinae
No full textSubfamily Rossellinae Schulze, 1885Published as part of Kahn, Amanda S., Geller, Jonathan B., Reiswig, Henry M. & Smith, Kenneth L., 2013, Bathydorus laniger and Docosaccus maculatus (Lyssacinosida; Hexactinellida): Two new species of glass sponge from the abyssal eastern North Pacific Ocean, pp. 386-400 in Zootaxa 3646 (4) on page 388, DOI: 10.11646/zootaxa.3646.4.4, http://zenodo.org/record/22347
Lyssacinosida Zittel 1877
No full textOrder Lyssacinosida Zittel, 1877Published as part of <i>Kahn, Amanda S., Geller, Jonathan B., Reiswig, Henry M. & Smith, Kenneth L., 2013, Bathydorus laniger and Docosaccus maculatus (Lyssacinosida; Hexactinellida): Two new species of glass sponge from the abyssal eastern North Pacific Ocean, pp. 386-400 in Zootaxa 3646 (4)</i> on page 388, DOI: 10.11646/zootaxa.3646.4.4, <a href="http://zenodo.org/record/223479">http://zenodo.org/record/223479</a>
Rossellidae Schulze 1885
No full textFamily Rossellidae Schulze, 1885Published as part of <i>Kahn, Amanda S., Geller, Jonathan B., Reiswig, Henry M. & Smith, Kenneth L., 2013, Bathydorus laniger and Docosaccus maculatus (Lyssacinosida; Hexactinellida): Two new species of glass sponge from the abyssal eastern North Pacific Ocean, pp. 386-400 in Zootaxa 3646 (4)</i> on page 388, DOI: 10.11646/zootaxa.3646.4.4, <a href="http://zenodo.org/record/223479">http://zenodo.org/record/223479</a>
FIGURE 1 in Bathydorus laniger and Docosaccus maculatus (Lyssacinosida; Hexactinellida): Two new species of glass sponge from the abyssal eastern North Pacific Ocean
No full textFIGURE 1. Collection location of two new species of glass sponges with a unique plate-like morphology: Station M (4,100 m depth, 34º50'N, 123º0'W), a long-term abyssal study site in the northeast Pacific.Published as part of Kahn, Amanda S., Geller, Jonathan B., Reiswig, Henry M. & Smith, Kenneth L., 2013, Bathydorus laniger and Docosaccus maculatus (Lyssacinosida; Hexactinellida): Two new species of glass sponge from the abyssal eastern North Pacific Ocean, pp. 386-400 in Zootaxa 3646 (4) on page 387, DOI: 10.11646/zootaxa.3646.4.4, http://zenodo.org/record/22347
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Climate variation, carbon flux, and bioturbation in the abyssal North Pacific
No full textWe 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
- …
