Realm: Marine
Climate: Temperate
Biome: Temperate shelf and seas ecoregions
Central latitude: 34.917990
Central longitude: -123.025626
Duration: 10 years, from 1991 to 2011

1730 records

141 distinct species

Across the time series Levinsenia spA is the most frequently occurring species

Methods

2.1. Study area macrofauna sampling and species identification - We used data from twenty-two research cruises (Table 1) from 1991 to 2011 conducted at Sta. M in the North East Pacific (Smith and Druffel 1998). To accommodate the water depth limitations of the remotely operated vehicles Tiburon and Doc Ricketts used during later collections the sampling area was relocated some 40 km between the 1991 and 2005 period (34?50?N 123?00?W c. 4100 m water depth) and the present (35?10?N 122?59?W c. 4000 m water depth; Fig. 1). Macrofauna were sampled with a free-vehicle grab respirometer (FVGR; Smith et al. 2001) a system comprised of four 413-cm2 grabs that collected the top 15 cm of the sediment column (Table 1). After recovery sediment from each grab was sieved through a 300 ?m mesh and preserved in 10% borax-buffered formalin solution. All polychaete specimens recovered from the grab samples were identified to species level using high-power microscopes (Zeiss Discovery v20 Stereo and high power Leica DM 5000 B) published identification keys and original taxonomic descriptions (e.g. Fauchald 1972 Fauchald 1977 and Fauchald and Hancock 1981). Only individuals with a head were considered in the subsequent analyses to give an objective assessment of density and diversity with respect to individual counts (Paterson et al. 2009). Of the 3800 headed-individuals 3646 could be classified to family level and 3077 to species level. Many species appeared to be undescribed and were designated as sp. A sp. B and so forth. Each family was assigned to a single functional group among those defined by Fauchald and Jumars (1979) as detailed in Laguionie-Marchais et al. (2013) and in Table 2. 2.2. Proxies of polychaete biomass and energy use rate. Of the 3077 identified specimens only 100 were complete individuals consequently a proxy of polychaete body volume was employed. The width of the first chaetiger (W1) was measured for all specimens (see Paterson et al. 2006) and cubed as a proxy for individual body mass (=W13). Proxy rates of energy use (respiration R) were then estimated for each specimen using standard mass scaling (e.g. mass3/4 Brown et al. 2004) such that proxy energy use rate R = (W13)3/4 = W12.25. Neither a proportionality coefficient nor a temperature coefficient was applied as in situ temperature was near-constant at Sta. M ( Ruhl et al. 2014). Hereafter the terms proxy biomass and proxy energy use rate are simply referred to as biomass and energy use rate. Grabs Unit of abundance = IndCountInt, Unit of biomass = Weight

Citation(s)

Laguionie-Marchais, C., Billett, D. S. M., Paterson, G. L. D., Ruhl, H. A., Soto, E. H., Smith, J. L. & Thatje, S. (2013) Inter-annual dynamics of abyssal polychaete communities in the North East Pacific and North East Atlantic-A family-level study. Deep-Sea Research Part I: Oceanographic Research Papers, 75, 175–186.
Laguionie-Marchais, C., Paterson, G. L. J., Bett, B. J., Smith, K. L. & Ruhl, H. A. (2016) Inter-annual species-level variations in an abyssal polychaete assemblage (Sta. M, NE Pacific, 4000 m). Progress in Oceanography, 140, 43–53.