Measuring primary production rates in the ocean: Enigmatic results between incubation and non‐incubation methods at Station ALOHA

Abstract

[1] Primary production (PP) rates were estimated using concurrent 14 O-GOP rates by 25-60%, and possible methodological biases were evaluated. A supersaturation of the dissolved O 2 /Ar gas ratio was measured every month yielding a mean annual value of 101.3 ± 0.1% and indicating a consistent net autotrophic condition in the mixed layer at ALOHA. The mean annual net community production (NCP) rate at ALOHA estimated from dissolved O 2 /Ar gas ratio was 14 ± 4 mmol O 2 m −2 d −1 (120 ± 33 mg C m −2 d −1 or 3.7 ± 1.0 mol C m −2 yr −1) for the mixed layer. A NCP/GOP ratio of 0.19 ± 0.08 determined from

Biological production rates off the Southern California coast estimated from triple O2 isotopes and O2 : Ar gas ratios

“…One possible explanation for these high 18 O-GOP : 14 C-PP ratios is that the O 2 production to carbon fixation ratio increases under high light conditions, as discussed in Zehr and Kudela (2009). Although variability in light conditions may contribute to the high seasonal variability in 17 D-GOP : 14 C-PP 24h ratios at CalCOFI and BATS relative to HOT, it does not seem likely that variability in light conditions can explain the disparity between the annual mean 17 D-GOP : 14 C-PP 24h ratio of , 3 at HOT (Quay et al 2010) and , 6 for the Offshore region at CalCOFI, given that both sites are located in the oligotrophic subtropical North Pacific (Table 2). In any case, a better understanding of the variability in rates of photosynthetic O 2 production and corresponding carbon fixation for different plankton species under different light and nutrient conditions is clearly needed.…”

“…The Offshore region was least variable from cruise to cruise for all PP methods except 17 D-GOP, which was least variable in the South Inshore region (Table 3). The uncertainty in 17 D-GOP estimates makes the seasonal range difficult to distinguish in oligotrophic regions of the North Pacific as noted by Quay et al (2010). Table 2; Fig.…”

“…Thus, the recommendation from this and similar recent studies (Juranek and Quay 2005;Robinson et al 2009;Quay et al 2010) is to adopt a multipronged approach to PP and NCP measurement utilizing a suite of methods, each with their own biases, that in combination should better constrain biological productivity rates in the coastal ocean.…”

“…Several previous studies have employed the 17 D-GOP method in open-ocean environments, including at the Bermuda Atlantic Time-Series (BATS; Barkan 2000, 2009), the Hawaii Ocean Time-Series (HOT; Juranek and Quay 2005;Quay et al 2010), the subtropical North and South Pacific (Juranek and Quay 2010), the equatorial Pacific (Juranek and Quay 2010;Stanley et al 2010), the subarctic North Atlantic (Quay et al 2012), and the Southern Ocean (Hendricks et al 2004;Reuer et al 2007). The only previous studies to employ the 17 D-GOP method in the coastal ocean were conducted in Sagami Bay off the coast of Japan (Sarma et al 2008).…”

The interdisciplinary marine system of the Amundsen Sea, Southern Ocean: Recent advances and the need for sustained observations

“…Net community production (NCP), the source of export as well as sustenance for upper trophic levels, appeared to be 40-60% of the NPP (Yager et al, in review). This ratio, a key indicator of ecosystem production efficiency, is similar to a range of other ocean ecosystems including the subtropical gyres (Quay et al, 2010). This similarity across such widely divergent biomes suggests the existence of heretofore-unappreciated common structures in ocean biogeochemical systems.…”