Characterization of alkaline phosphatase activity in the North and South Pacific Subtropical Gyres: Implications for phosphorus cycling
Characterization of alkaline phosphatase activity in the North and South Pacific Subtropical Gyres: Implications for phosphorus cycling
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DOI：
10.4319/lo.2011.56.4.1244
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发表时间：
2011-07-01
影响因子：
4.5
通讯作者：
Karl, David M.
中科院分区：
文献类型：
--
作者：
Duhamel, Solange;Bjoerkman, Karin M.;Karl, David M.
本文研究了北太平洋和南太平洋副热带环流（NPSG和SPSG）中碱性磷酸酶（AP）活性（APA），并报道了AP动力学参数，以评价APA在溶解有机磷（DOP）再矿化中的相对重要性。在NPSG和中央SPSG的表面样品中，APA的潜在水解率较低，但可测量（0.10 +/- 0.06 nmol L-1 h(-1), n = 12，和0.13 +/- 0.08 nmol L-1 h21, n = 6）。与溶解无机磷（DIP）的吸收率相比，APA对DOP的潜在利用可能对这些贫营养栖息地的微生物群落很重要。假设ap可水解的DOP比例较高（80%）和较低（10%），则在NPSG的地表水中，APA可分别占DIP吸收率的25% +/- 18% （n = 11）和4% +/- 3% (n = 11)，在中央SPSG的地表水中，APA可分别占147% +/- 86% （n = 6）和20% +/- 12% （n = 6）。尽管SPSG的DIP较高，DOP较低，但与NPSG相比，SPSG的APA与DIP摄取的比例显著高于NPSG。半饱和常数（K-m）在两个环流测得的DOP浓度范围内，说明微生物可以根据DOP有效性调整其对DOP的利用。溶解的APA在NPSG中占总APA的很大一部分，在Sta时占总APA的12%至100% （41 +/- 23%,n = 23）。阿罗哈。有机磷的ap水解部分的利用可能有助于广泛的太平洋少营养环流的生产。
We characterized alkaline phosphatase (AP) activity (APA) and report AP kinetic parameters in the North and South Pacific Subtropical Gyres (NPSG and SPSG, respectively) to evaluate the relative importance of APA in dissolved organic P (DOP) remineralization. APA potential hydrolysis rates were low but measurable (0.10 +/- 0.06 nmol L-1 h(-1), n = 12, and 0.13 +/- 0.08 nmol L-1 h21, n = 6) in surface samples from the NPSG and central SPSG, respectively. When compared to dissolved inorganic P (DIP) uptake rates, the potential utilization of DOP by APA may be important for microbial communities in these oligotrophic habitats. Assuming an upper (80%) and a lower (10%) fraction of the DOP to be AP-hydrolyzable, APA could represent 25% +/- 18% (n = 11) and 4% +/- 3% (n = 11) of the DIP uptake, respectively, in surface waters of the NPSG and 147% +/- 86% (n = 6) and 20% +/- 12% (n = 6), respectively, in surface waters of the central SPSG. The ratio of APA to DIP uptake was significantly larger in the SPSG compared to the NPSG despite having higher DIP and lower DOP. The half-saturation constant (K-m) was in the range of DOP concentrations measured in the two gyres, meaning that microorganisms can adjust their DOP utilization according to DOP availability. Dissolved APA was a large fraction of total APA in the NPSG, contributing between 12% and 100% (41 +/- 23%, n = 23) of total APA at Sta. ALOHA. Utilization of the AP-hydrolyzable fraction of the DOP probably contributes to production in the extensive Pacific oligotrophic gyres.