The Porcupine Abyssal Plain fixed-point sustained observatory (PAP-SO): variations and trends from the Northeast Atlantic fixed-point time-series

Hartman, Susan E.; Lampitt, Richard S.; Larkin, Kate; Pagnani, Maureen; Campbell, Jon; Gkritzalis, Thanos; Jiang, Zhiping; Pebody, Corinne; Ruhl, Henry A.; Gooday, Andrew J.; Bett, Brian J.; Billett, David; Provost, Paul G; McLachlan, R; Turton, Jon; Lankester, Steven

doi:10.1093/icesjms/fss077

Cited by 50 publications

(37 citation statements)

References 20 publications

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“…The megabenthos of the PAP (48°50' N, 16°30' W; 4850 m water depth), in the vicinity of the sustained observatory (Hartman et al 2012), was studied. Seabed images were captured within a 1 km 2 area of level seafloor, distant from any significant seabed topography, such that no systematic variations in the density, diversity or taxonomic composition of the megafauna were expected.…”

Section: Study Design and Data Collectionmentioning

confidence: 99%

Comparison of image annotation data generated by multiple investigators for benthic ecology

Durden¹,

Bett²,

Schoening³

et al. 2016

Mar. Ecol. Prog. Ser.

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Multiple investigators often generate data from seabed images within a single image set to reduce the time burden, particularly with the large photographic surveys now available to ecological studies. These data (annotations) are known to vary as a result of differences in investigator opinion on specimen classification and of human factors such as fatigue and cognition. These variations are rarely recorded or quantified, nor are their impacts on derived ecological metrics (density, diversity, composition). We compared the annotations of 3 investigators of 73 megafaunal morphotypes in ~28 000 images, including 650 common images. Successful annotation was defined as both detecting and correctly classifying a specimen. Estimated specimen detection success was 77%, and classification success was 95%, giving an annotation success rate of 73%. Specimen detection success varied substantially by morphotype (12−100%). Variation in the detection of common taxa resulted in significant differences in apparent faunal density and community composition among investigators. Such bias has the potential to produce spurious ecological interpretations if not appropriately controlled or accounted for. We recommend that photographic studies document the use of multiple annotators and quantify potential inter-investigator bias. Randomisation of the sampling unit (photograph or video clip) is clearly critical to the effective removal of human annotation bias in multiple annotator studies (and indeed single annotator works).

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Section: Study Design and Data Collectionmentioning

confidence: 99%

Comparison of image annotation data generated by multiple investigators for benthic ecology

Durden¹,

Bett²,

Schoening³

et al. 2016

Mar. Ecol. Prog. Ser.

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“…Conversions were created using ~47 000 specimens collected in the vicinity of the Porcupine Abyssal Plain Sustained Observatory Site (PAP; 48°50' N, 16°30' W, 4850 m water depth; Hartman et al 2012) using a semi-balloon otter trawl (Billett et al 2001) on a number of research cruises between August 1996 and October 2002: RRS 'Discovery' 222 (Rice 1996), 226 (Rice 1997), 229 (Bett 1998), 231 (Rice 1998), 237 (Sibuet 1999), and 266;and RRS 'Challenger' 135 (Billett 1998) and 142 (Billett 2000). Specimens were fixed in borax-buffered 10% formalin-seawater at sea, and subsequently transferred to 80% industrial denatured alcohol for long-term preservation once ashore (generally within 2 months of sample collection).…”

Section: Dimension To Wet Weight Conversions From Trawled Specimensmentioning

confidence: 99%

Improving the estimation of deep-sea megabenthos biomass: dimension to wet weight conversions for abyssal invertebrates

Durden¹,

Bett²,

Horton³

et al. 2016

Mar. Ecol. Prog. Ser.

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Deep-sea megafaunal biomass has typically been assessed by sampling with benthic sledges and trawls, but non-destructive methods, particularly photography, are becoming increasingly common. Estimation of individual wet weight in seabed photographs has been achieved using equations obtained from measured trawl-caught specimens for a limited number of taxa. However, a lack of appropriate conversion factors has limited estimation across taxa encompassing whole communities. Here we compile relationships between measured body dimensions and preserved wet weights for a comprehensive catalogue of abyssal epibenthic megafauna, using 47 000 specimens from the Porcupine Abyssal Plain (NE Atlantic) housed in the Discovery Collections (National Oceanography Centre, Southampton, UK). The practical application of the method is demonstrated using an extremely large dataset of specimen measurements from seabed photographs taken in the same location. We also collate corresponding field data on fresh wet weight, to estimate the impact of fixation in formalin and preservation in industrial denatured alcohol on the apparent biomass. Taxa with substantial proportions of soft tissues lose 35 to 60% of their wet weight during preservation, while those with greater proportions of hard tissues lose 10 to 20%. Our total estimated fresh wet weight biomass of holothurians and cnidarians in the photo graphic survey was ~20 times the previous estimates of total invertebrate biomass based on trawl catches. This dramatic uplift in megabenthic biomass has significant implications for studies of standing stocks, community metabolism, and numerical modelling of benthic carbon flows.

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“…• W (4850 m water depth) where a fixed-point mooring has been in place since 2002 (Hartman et al, 2012). The PAP-SO is in the North Atlantic Drift Region, a biogeographical province defined by deep winter convective mixing (Longhurst, 2006;Monterey and Levitus, 1997).…”

Section: S E Hartman Et Al: Biogeochemical Variations At the Porcumentioning

confidence: 99%

“…Despite the similar winter physical conditions (temperature and MLD), there is a year to year difference in the timing and intensity of the spring blooms, which requires further investigation. At PAP-SO, increasing mean seawater p(CO 2 ) from (339 ± 17) µatm in 2003 to (353 ± 15) In 2010, collaboration between the UK's Natural Environment Research Council (NERC) and Meteorological Office led to the first simultaneous monitoring of in situ meteorological and ocean variables at the PAP-SO (Hartman et al, 2012). From 2013 additional measurements of p(CO 2 ) will be made at the site, at the shallower depth of 1 m, and should further improve the SOO comparison.…”

Section: Conclusion and Further Workmentioning

confidence: 99%

Biogeochemical variations at the Porcupine Abyssal Plain sustained Observatory in the northeast Atlantic Ocean, from weekly to inter-annual timescales

et al. 2015

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Abstract. We present high-resolution autonomous measurements of carbon dioxide partial pressure p(CO 2 ) taken in situ at the Porcupine Abyssal Plain sustained Observatory (PAP-SO) in the northeast Atlantic (49• N, 16.5 • W; water depth of 4850 m) for the period 2010-2012. Measurements of p(CO 2 ) made at 30 m depth on a sensor frame are compared with other autonomous biogeochemical measurements at that depth (including chlorophyll a fluorescence and nitrate concentration data) to analyse weekly to seasonal controls on p(CO 2 ) flux in the inter-gyre region of the North Atlantic. Comparisons are also made with in situ regional time series data from a ship of opportunity and mixed layer depth (MLD) measurements from profiling Argo floats. There is a persistent under-saturation of CO 2 in surface waters throughout the year which gives rise to a perennial CO 2 sink. Comparison with an earlier data set collected at the site (2003)(2004)(2005) confirms seasonal and inter-annual changes in surface seawater chemistry. There is year-to-year variability in the timing of deep winter mixing and the intensity of the spring bloom.The 2010-2012 period shows an overall increase in p(CO 2 ) values when compared to the 2003-2005 period as would be expected from increases due to anthropogenic CO 2 emissions. The surface temperature, wind speed and MLD measurements are similar for both periods of time. Future work should incorporate daily CO 2 flux measurements made using CO 2 sensors at 1 m depth and the in situ wind speed data now available from the UK Met Office Buoy.

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The Porcupine Abyssal Plain fixed-point sustained observatory (PAP-SO): variations and trends from the Northeast Atlantic fixed-point time-series

Cited by 50 publications

References 20 publications

Comparison of image annotation data generated by multiple investigators for benthic ecology

Comparison of image annotation data generated by multiple investigators for benthic ecology

Improving the estimation of deep-sea megabenthos biomass: dimension to wet weight conversions for abyssal invertebrates

Biogeochemical variations at the Porcupine Abyssal Plain sustained Observatory in the northeast Atlantic Ocean, from weekly to inter-annual timescales

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