Responses of biological and chemical components in North East Atlantic coastal water to experimental nitrogen and phosphorus addition – A full scale ecosystem study and its relevance for management.

Olsen, Yngvar, Reinertsen, Helge, Sommer, Ulrich and Vadstein, Olav (2014) Responses of biological and chemical components in North East Atlantic coastal water to experimental nitrogen and phosphorus addition – A full scale ecosystem study and its relevance for management. Open Access Science of the Total Environment, 473-474 . pp. 262-274. DOI 10.1016/j.scitotenv.2013.12.028.

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Supplementary data:

Abstract

Highlights:
• A full-scale 5 year experimental study of ecosystem responses to increased nutrients.
• Concentrations of DIN and DIP did not respond positively to increased nutrient input.
• Concentrations of PON and POP and phytoplankton biomass responded positively.
• PON is suggested as credible indicator for chemical and ecological state.
• A general scientific concept for managing nutrient input to coastal waters is presented.

Abstract:
The objective of this study was to quantify chemical and biological responses to an experimentally increased nutrient input to an open coastal planktonic ecosystem and to contribute to a scientific concept and credible indicators for managing nutrient supply to coastal waters. Data were derived in a 5 year fertilisation experiment of a tidal driven coastal lagoon at the outer coast off Central Norway (63°36’ N, 9°33’ E), with a surface area of 275.000 m2, volume of 5.5 mill m3, mean depth of 22 m and a water exchange rate of 0.19 day- 1. The lagoon was fertilised in the summer season 1998 and 1999, while summer seasons 1996-97 and 2000 and inflowing water were used as unfertilised references. Most measured chemical and biological variables showed linear responses with an increasing loading rate of inorganic N and P (LN and LP, respectively). PON, POP and POC (< 200 μm) responded significantly (P < 0.05) as did chlorophyll a and phytoplankton C. DIN and DIP remained, however, constant and independent of LN and LP, respectively (P > 0.05) as did heterotrophic biomass (P > 0.05). We evaluate the response variables assuming a stepwise incorporation process of nutrients in the planktonic ecosystem and how that will interact with biological response times and water dilution rates. We suggest that PON is a credible indicator of both chemical and ecological states of the planktonic ecosystem and that natural background and upper critical concentrations are 46 and 88 mg PON m- 3, respectively. The study was supported by data from mesocosms. We discuss the scientific relevance of our suggestions, how results can be extrapolated to a broader geographical scale, and we propose a science-based concept for the management of nutrient emission to open coastal waters.

Document Type: Article
Additional Information: WOS:000331923900032
Keywords: Experimental eutrophication; North East Atlantic; Biological and chemical responses; PON and POP; Indicators; Management concept
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-N Experimental Ecology - Food Webs
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.1016/j.scitotenv.2013.12.028
ISSN: 0048-9697
Projects: COMWEB, Future Ocean
Date Deposited: 24 Jan 2014 07:09
Last Modified: 08 Sep 2016 07:40
URI: http://oceanrep.geomar.de/id/eprint/23206

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