@article {7,
	title = {Material supply to the abyssal seafloor in the Northeast Atlantic},
	journal = {Progress in OceanographyProgress in OceanographyProgress in Oceanography},
	volume = {50},
	number = {1-4},
	year = {2001},
	note = {Sp. Iss. SI488RPTimes Cited:122Cited References Count:65},
	pages = {27-63},
	abstract = {Downward particle flux was measured using sediment traps at various depths over the Porcupine Abyssal Plain (water depth similar to 4850 m) for prolonged periods from 1989 to 1999. A strong seasonal pattern of flux was evident reaching a maximum in mid-summer. The composition of the material changed with depth, reflecting the processes of remineralisation and dissolution as the material sank through the water column. However, there was surprisingly little seasonal variation in its composition to reflect changes in the biology of the cuphotic zone.Currents at the site have a strong tidal component with speeds almost always less than 15 cm/sec. In the deeper part of the water column they tend to be northerly in direction, when averaged over periods of several months.A model of upper ocean biogeochemistry forced by meteorology was run for the decade in order to provide an estimate of flux at 3000 m depth. Agreement with measured organic carbon flux is good, both in terms of the timings of the annual peaks and in the integrated annual flux. Interannual variations in the integrated flux are of similar magnitude for both the model output and sediment trap measurements, but there is no significant relationship between these two sets of estimates. No long-term trend in flux is evident, either from the model, or from the measurements.During two spring/summer periods, the marine snow concentration in the water column was assessed by time-lapse photography and showed a strong peak at the start of the downward pulse of material at 3000 m. This emphasises the importance of large particles during periods of maximum flux and at the start of flux peaks. Time lapse photographs of the seabed show a seasonal cycle of coverage of phytodetrital material, in agreement with the model output both in terms of timing and magnitude of coverage prior to 1996. However, after a change in the structure of the benthic community in 1996 no phytodetritus was evident on the seabed.The model output shows only a single peak in flux each year, whereas the measured data usually indicated a double peak. It is concluded that the observed double peak may be a reflection of lowered sediment trap efficiency when flux is very high and is dominated by large marine snow particles.Resuspension into the trap 100 rn above the seabed, when compared to the primary flux at 3000 m depth (1800 mab) was lower during periods of high primary flux probably because of a reduction in the height of resuspension when the material is fresh. At 2 mab, the picture is more complex with resuspension being enhanced during the periods of higher flux in 1997, which is consistent with this hypothesis. However there was rather little relationship to flux at 3000 m in 1998.At 3000 m depth, the Flux Stability Index (FSI), which provides a measure of the constancy of the seasonal cycle of flux, exhibited an inverse relationship with flux, such that the highest flux of organic carbon was recorded during the year with the greatest seasonal variation. (C) 2001 Elsevier Science Ltd. All rights reserved.},
	keywords = {biogenic particle fluxes, bloom experiment, marine snow, ocean sediment traps, pacific, particulate organic-carbon, sargasso-sea, seasonal deposition, temporal variability, water column},
	isbn = {0079-6611},
	author = {Lampitt, R. S. and Bett, B. J. and Kiriakoulakis, K. and Popova, E. E. and Ragueneau, O. and Vangriesheim, A. and Wolff, G. A.}
}
@article {9,
	title = {Long-term variability of downward particle flux in the deep northeast Atlantic: Causes and trends},
	journal = {Deep-Sea Research Part II-Topical Studies in OceanographyDeep-Sea Research Part Ii-Topical Studies in OceanographyDeep-Sea Research Part Ii-Topical Studies in Oceanography},
	volume = {57},
	number = {15},
	year = {2010},
	note = {634DWTimes Cited:22Cited References Count:78},
	month = {Aug 1},
	pages = {1346-1361},
	abstract = {At 3000 m depth the downward flux of particulate matter shows substantial seasonal and interannual variation. Complete annual records for eight of the past 14 years have been examined in the light of mixing depths derived from the OCCAM general circulation model and euphotic zone chlorophyll concentration and productivity, which were derived from the SeaWiFS satellite colour sensor. The annual flux was particularly high in 2001 due to a late summer deposition exceeding previous records several fold and this year was also characterised by very early shoaling of the mixing depth in spring and a very high surface spring chlorophyll concentration. Other years that were somewhat unusual in having either high or low flux at depth were not in general associated with unusual patterns of mixing or productivity. The percentage of the annual organic carbon primary production which reaches 3000 m varies from 0.6 to 1.2\% except in 2001 when it reached 3.4\%. A mechanistic relationship between upper-ocean processes and deep-ocean particle flux remains elusive and various explanations are suggested for this which need now to be addressed. In the spring, the timing of first shoaling of mixing, enhancement of productivity and increased particle flux at depth have all advanced during the 14 years of study by about 2 days per year, suggesting a similar trend as has been observed for surface phytoplankton, mesozooplankton, fish and seabirds probably caused by wide-scale environmental changes. (C) 2010 Published by Elsevier Ltd.},
	keywords = {biogenic opal, climate, downward particle flux, export, inter-annual variability, interannual variability, mixed-layer depth, ocean, organic-carbon fluxes, primary production, primary productivity, sargasso sea, sediment traps, time-series},
	isbn = {0967-0645},
	author = {Lampitt, R. S. and Salter, I. and de Cuevas, B. A. and Hartman, S. and Larkin, K. E. and Pebody, C. A.}
}
@article {10,
	title = {The Porcupine Abyssal Plain fixed-point sustained observatory (PAP-SO): variations and trends from the Northeast Atlantic fixed-point time-series},
	journal = {ICES Journal of Marine ScienceIces Journal of Marine ScienceIces Journal of Marine Science},
	volume = {69},
	number = {5},
	year = {2012},
	note = {961JHTimes Cited:0Cited References Count:20},
	month = {Jul},
	pages = {776{\textendash}783},
	abstract = {The Porcupine Abyssal Plain sustained observatory (PAP-SO) in the Northeast Atlantic (498N 16.58W; 4800 m) is the longest running open-ocean multidisciplinary observatory in the oceans around Europe. The site has produced high-resolution datasets integrating environmental and ecologically relevant variables from the surface to the seabed for >20 years. Since 2002, a full-depth mooring has been in place with autonomous sensors measuring temperature, salinity, chlorophyll-a fluorescence, nitrate, and pCO2. These complement ongoing mesopelagic and seabed observations on downward particle flux and benthic ecosystem structure and function. With national and European funding, the observatory infrastructure has been advanced steadily, with the latest development in 2010 involving collaboration between the UK{\textquoteright}s Meteorological Office and Natural Environment Research Council. This resulted in the first simultaneous atmospheric and ocean datasets at the site. All PAP-SO datasets are open access in near real time through websites and as quality-controlled datasets for a range of remote users using ftp sites and uploaded daily to MyOcean and the global telecommunications system for use in modelling activities. The combined datasets capture short-term variation (daily-seasonal), longer term trends (climate-driven), and episodic events (e. g. spring-bloom events), and the data contribute to the Europe-wide move towards good environmental status of our seas, driven by the EU{\textquoteright}s Marine Strategy Framework Directive (http://ec. europa. eu/ environment/water/marine).},
	keywords = {climate, driven, long-term change, northeast atlantic, observatory, Porcupine Abyssal Plain, time-series},
	isbn = {1054-3139},
	author = {Hartman, S. E. and Lampitt, R. S. and Larkin, K. E. and Pagnani, M. and Campbell, J. and Gkritzalis, T. and Jiang, Z. P. and Pebody, C. A. and Ruhl, H. A. and Gooday, A. J. and Bett, B. J. and Billett, D. S. M. and Provost, P. and McLachlan, R. and Turton, J. D. and Lankester, S.}
}
