Alkaline phosphatase activity related to phosphorus stress of microphytoplankton in different trophic conditions

Ivančić, Ingrid; Pfannkuchen, Martin; Godrijan, Jelena; Djakovac, Tamara; Marić Pfannkuchen, Daniela; Korlević, Marino; Gašparović, Blaženka; Najdek-Dragić, Mirjana (2016) Alkaline phosphatase activity related to phosphorus stress of microphytoplankton in different trophic conditions. Progress in Oceanography, 146 . pp. 175-186. ISSN 0079-6611

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Abstract

The northern Adriatic (NA) is a favorable basin for studying the adaptive strategies of plankton to a variety of conditions along the steep gradients of environmental parameters over the year. Earlier studies identified phosphorus(P) limitation as one of the key stresses within the NA that shape the biological response in terms of biodiversity and metabolic adjustments. A wide range of reports supports the notion that P-limitation is a globally important phenomenon in aquatic ecosystems. In this study P stress of marine microphytoplankton was determined at species level along a trophic gradient in the NA. In P-limitation all species with considerable contributions to the diatom community expressed alkaline phosphatase activity (APA), compared to only a few marginal dinoflagellate species. Nevertheless, APA expressing species did not always dominate the phytoplankton community, suggesting that APA is also an important strategy for species to survive and maintain active metabolism outside of their mass abundances. A symbiotic relationship could be supposed for diatoms that did not express APA themselves and probably benefited from APA expressed by attached bacteria. APA was not expressed by any microphytoplankton species during the autumn when P was not limiting, while most of the species did express APA during the P-limitation. This suggests that APA expression is regulated by orthophosphate availability. The methods employed in this study allowed the microscopic detection of APA for each microphytoplankton cell with simultaneous morphologic/taxonomic analysis. This approach uncovered a set of strategies to compete in P-limited conditions within the marine microphytoplankton community. This study confirms the role of P-limitation as a shaping factor in marine ecosystems.

Item Type:	Article
Uncontrolled Keywords:	alkaline phosphatase ; phytoplankton ; nutrients ; DOP ; P-limitation ; northern Adriatic
Subjects:	NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science
Divisions:	Center for Marine Research
Projects:	Project title Project leader Project code Project type Životne strategije fitoplanktona u sjevernom Jadranu-P-limit Andreas Pfannkuchen Martin UIP-2014-09-6563 HRZZ Mehanizam dugoročnih promjena u ekosustavu sjevernog Jadrana- Robert Precali 098-0982705-2731 MZOS Struktura i fiziologija mikrobnih zajednica frontalnih zona sjevernog Jadrana- Mirjana Najdek-Dragić 098-0982705-2729 MZOS
Depositing User:	Blaženka Gašparović
Date Deposited:	22 May 2018 08:47
URI:	http://fulir.irb.hr/id/eprint/4059
DOI:	10.1016/j.pocean.2016.07.003

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