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Biogeochemistry

, Volume 113, Issue 1–3, pp 153–166 | Cite as

The contribution of the deep chlorophyll maximum to primary production in a seasonally stratified shelf sea, the North Sea

  • Liam FernandEmail author
  • Keith Weston
  • Tom Morris
  • Naomi Greenwood
  • Juan Brown
  • Tim Jickells
Article

Abstract

Results from extensive cruises in the years 2000 and 2001 throughout distinct ecohydrodynamic regions of the central and southern North Sea are presented and used to generate estimates of gross primary production and new production. An undulating CTD fitted with a fluorometer was towed over a distance of 12,000 kms. Fluorescence data were used to determine the chlorophyll distribution and derive estimates of phytoplankton biomass. These results were combined with estimates of primary production (new and regenerated) from experiments from one cruise in order to estimate gross production for a greater geographical extent. Results from repeat inter-annual transects showed that the strength of the thermocline and the associated deep chlorophyll maximum were variable. However, when the primary production was integrated over the 15–40 m depth, the variability between years was low. While the depth and strength of the deep chlorophyll maximum varied across the region, a deep chlorophyll maximum (DCM) is a consistent and widespread feature of this region at around 30 m depth. In 2001 the calculated average primary production rate in summer for the whole area surveyed was 0.91 g C m−2 day−1. This daily production equates to ~130 g C m−2 for the summer stratified period. In the offshore stratified regions around the Dogger Bank and Eastern Central North Sea primary production of 64 g C m−2 associated with the deep chlorophyll maximum (15–40 m) accounted for 60 % of total primary production during the summer stratified period (after the spring bloom). Approximately 66 % of new production in these areas occurred in the DCM. This study shows the extent of the DCM in the North Sea and demonstrates its importance in sustaining primary production after the spring bloom.

Keywords

North Sea Towed undulator Deep chlorophyll maximum Primary productivity 

Notes

Acknowledgments

This work has been funded by number of DEFRA contracts these being: Consensus on Pathways (AE1225) Maintenance of thin layers (AE1219) and Adapatation to Climate Change in the Marine Environment (ACME). Jickells and Morris were funded by NERC/DEFRA project Sustainable Marine Bioresources grant NE/F001932/1. The authors wish to thank the officers and crew of the RV Corystes for their advice and good humour. It has also been much improved due to the helpful suggestions of the anonymous reviewers.

References

  1. Abdel-Moati AR (1990) Particulate organic matter in the subsurface chlorophyll maximum layer of the southeastern Mediterranean. Oceanol Acta 13:307–315Google Scholar
  2. Bo Pedersen F (1994) The oceanographic and biological cycle succession in shallow sea fronts in the North Sea and the English Channel. Estuar Coast Shelf Sci 38:249–269CrossRefGoogle Scholar
  3. Brown JB, Brander KM, Fernand L (1996) Scanfish: a high performance towed undulator. Sea Technol 37:23–28Google Scholar
  4. Capuzzo E, Painting SJ, Forster RM, Greenwood N, Stephens DT, Mikkelsen OA (2012) Variability in the sub-surface light climate at ecohydrodynamically distinct sites in the North Sea. Biogeochemistry. doi: 10.1007/s10533-012-9772-6 Google Scholar
  5. Carini SA, McCarthy MJ, Gardner WS (2010) An isotope dilution method to measure nitrification rates in the northern Gulf of Mexico and other eutrophic waters. Cont Shelf Res 30:1795–1801CrossRefGoogle Scholar
  6. Charnock H, Dyer KR, Huthnance JM, Liss PS, Simpson JH, Tett PB (1994) Understanding the North Sea system. Chapman and Hall, LondonCrossRefGoogle Scholar
  7. Cullen JJ (1982) The deep chlorophyll maximum: comparing vertical profiles of chlorophyll a. Can J Fish Aquat Sci 39:791–803CrossRefGoogle Scholar
  8. Defra (2011) NetGain final recommendations submission to Natural England and JNCC, pp. 880Google Scholar
  9. Dugdale RC, Goering JJ (1967) Uptake of new and regenerated forms of nitrogen in primary productivity. Limnol Oceanogr 12:196–206CrossRefGoogle Scholar
  10. Fernand L (1999) High resolution observations of the velocity filed and thermohaline structure of the western Irish Sea gyre. School of Ocean Sciences, University of Wales, Bangor, pp. 99Google Scholar
  11. Fernand L, Brown J, Read JW, Pizzamei M, Horsburgh K, Tinton E, Dye SR, Parker ER, Mills DK (2002) Direct observations and modelling of the secondary circulation associated with a tidal mixing front. Eos Trans Am Geophys Un, Honolulu, Hawaii (American Geophysical Union Abstract OS pp. 32D–143)Google Scholar
  12. Gieskes WWC, Kraay GW (1977) Primary production and consumption of organic matter in the southern North Sea during the spring bloom of 1975. Neth J Sea Res 11:146–167CrossRefGoogle Scholar
  13. Greenwood N, Parker ER, Fernand L, Sivyer DB, Weston K, Painting SJ, Kröger S, Forster RM, Lees HE, Mills DK, Laane RWPM (2010) Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health. Biogeosciences 7:1357–1373CrossRefGoogle Scholar
  14. Heath MR, Beare DJ (2008) New primary production in northwest European shelf seas, 1960–2003. Mar Ecol Prog Ser 363:183–203CrossRefGoogle Scholar
  15. Joint I, Pomroy A (1993) Phytoplankton biomass and production in the southern North Sea. Mar Ecol Prog Ser 99:169–182CrossRefGoogle Scholar
  16. Kirk JTO (1994) Light and photosynthesis in aquatic ecosystems, 2nd edn. Cambridge University Press, Cambridge, pp 509CrossRefGoogle Scholar
  17. Kuosa H (1990) Subsurface chlorophyll maximum in the northern Baltic Sea. Arch Hydrobiol 118:437–447Google Scholar
  18. Lee AJ (1980) The North Sea: physical oceanography. In: Banner FT, Collins MB, Massie KS (eds) The north–west European shelf seas: the sea bed and the sea in motion physical and chemical oceanography, and physical resources, vol 2. Elsevier, Amsterdam, pp 467–493CrossRefGoogle Scholar
  19. Lewis MR, Smith JC (1983) A small volume, short-incubation-time method for measurement of photosynthesis as a function of incident irradiance. Mar Ecol Prog Ser 13:99–102CrossRefGoogle Scholar
  20. Lohrenzen CJ (1966) A method for the continuous measurement of in vivo chlorophyll concentration. Deep Sea Res 13:223–227Google Scholar
  21. Lowe JA, Howard TP, Pardaens A, Tinker J, Holt J, Wakelin S, Milne G, Leake J, Wolf J, Horsburgh K, Reeder T, Jenkins G, Ridley J, Dye S, Bradley S (2009) UK Climate Projections science report marine and coastal projections. Met Office, Exeter, p 99Google Scholar
  22. Nielsen TG, Løkkegård B, Richardson K, Bo Pedersen F, Hansen L (1993) The structure of plankton communities in the Dogger Bank area (North Sea) during a stratified situation. Mar Ecol Prog Ser 95:115–131CrossRefGoogle Scholar
  23. Owens NJP, Woodward EMS, Aiken J, Bellan I, Rees AP (1990) Primary production and nitrogen assimilation in the North Sea during July 1987. J Sea Res 25:143–154CrossRefGoogle Scholar
  24. Pauly D, Christensen V (1995) Primary production required to sustain global fisheries. Nature 374:255–257CrossRefGoogle Scholar
  25. Pingree RD, Griffiths DK (1978) Tidal fronts on the shelf seas around the British Isles. J Geophys Res 83(C9):4615CrossRefGoogle Scholar
  26. Rees AP, Joint I, Donald KM (1999) Early spring bloom phytoplankton-nutrient dynamics at the Celtic Sea shelf edge. Deep Sea Res I:485–510Google Scholar
  27. Revelante N, Gilmartin M (1995) The relative increase of larger phytoplankton in a subsurface chlorophyll maximum of the northern Adriatic Sea. J Plankton Res 17:1535–1562CrossRefGoogle Scholar
  28. Richardson K, Bo Pedersen F (1998) Estimation of new production in the North Sea: consequences for temporal and spatial variability of phytoplankton. ICES J Mar Sci 55:574–580CrossRefGoogle Scholar
  29. Richardson K, Christofferson AP (1991) Seasonal distribution and production of phytoplankton in the southern Kattegat. Mar Ecol Prog Ser 78:217–227CrossRefGoogle Scholar
  30. Richardson K, Gissel Neilsen T, Bo Pedersen F, Heilmann JP, Løkkegård B, Kaas H (1998) Spatial heterogeneity in the structure of the planktonic food web in the North Sea. Mar Ecol Prog Ser 168:1097–1211CrossRefGoogle Scholar
  31. Richardson K, Visser AW, Bo Pedersen F (2000) Subsurface phytoplankton blooms fuel pelagic production in the North Sea. J Plankton Res 22:1663–1671CrossRefGoogle Scholar
  32. Riegman R, Nordeloos AAM (1994) Size-fractionated uptake of nitrogenous nutrients and carbon by phytoplankton in the North Sea during summer 1994. Mar Ecol Prog Ser 173:85–94CrossRefGoogle Scholar
  33. Riegman R, Colijn F, Malschaert JFP, Kloosterhuis HT, Cadee GC (1990) Assessment of growth rate limiting nutrients in the North Sea by the use of nutrient-uptake kinetics. Neth J Sea Res 26:53–60CrossRefGoogle Scholar
  34. Ryther J (1969) Photosynthesis and fish production in the sea. Science 166:72–76CrossRefGoogle Scholar
  35. Scott B, Sharples J, Ross O, Wang J, Pierce G, Camphuysen C (2010) Sub-surface hotspots in shallow seas: fine-scale limited locations of top predator foraging habitat indicated by tidal mixing and sub-surface chlorophyll. Mar Ecol Prog Ser 408:207–226CrossRefGoogle Scholar
  36. Sharples J, Moore C, Rippeth T, Holligan P, Hydes D, Fisher N, Simpson J (2001) Phytoplankton distribution and survival in the thermocline. Limnol Oceanogr 46:486–496CrossRefGoogle Scholar
  37. Skogen M, Søiland H, Svendsen E (2004) Effects of changing nutrient loads to the North Sea. J Mar Syst 46:23–28CrossRefGoogle Scholar
  38. Smetaceck V, von Bodungen B, Knoppers B, Peinert R, Pollehne F, Stegmann P, Zeitschel B (1984) Seasonal stages characterizing the annual cycle of an inshore pelagic system. Rapp Cons Int Explor Mer 183:126–135Google Scholar
  39. Spokes LJ, Jickells T (2005) Is the atmosphere really an important source of reactive nitrogen to coastal waters? Cont Shelf Res 25:2022–2035CrossRefGoogle Scholar
  40. van Leeuwen SM, van der Molen J, Ruardij P, Fernand L, Jickells T (2012) Modelling the contribution of deep chlorophyll maxima to annual primary production in the North Sea. Biogeochemistry. doi: 10.1007/s10533-012-9704-5 Google Scholar
  41. Walsby AE (1997) Numerical integration of phytoplankton photosynthesis through time and depth in a water column. New Phytol 136:189–209CrossRefGoogle Scholar
  42. Weston K, Fernand L, Mills DK, Delahunty R, Brown J (2005) Primary production in the deep chlorophyll maximum of the central North Sea. J Plankton Res 27:909–922CrossRefGoogle Scholar
  43. Yool A, Martin AP, Fernandez C, Clark DR (2007) The significance of nitrification for oceanic new production. Nature 447:999–1002CrossRefGoogle Scholar

Copyright information

© UK Crown 2013

Authors and Affiliations

  • Liam Fernand
    • 1
    Email author
  • Keith Weston
    • 1
  • Tom Morris
    • 2
  • Naomi Greenwood
    • 1
  • Juan Brown
    • 3
  • Tim Jickells
    • 4
  1. 1.Centre for Environment, Fisheries and Aquaculture ScienceSuffolkUK
  2. 2.Emu LimitedSouthamptonUK
  3. 3.British Oceanographic Data CentreMerseysideUK
  4. 4.School of Environmental SciencesUniversity of East AngliaNorwichUK

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