Effects of nutrient enrichments on oligotrophic phytoplankton communities: a mesocosm experiment near Hawai‘i, USA.

Böttjer-Wilson, Daniela, White, Angelicque E., Björkman, Karin M., Church, Matthew J., Poulos, Steve, Shimabukuro, Eric, Rii, Yoshimi M., Ludwig, Andrea, von Bröckel, Klaus, Riebesell, Ulf , Letelier, Ricardo M. and Karl, David M. (2021) Effects of nutrient enrichments on oligotrophic phytoplankton communities: a mesocosm experiment near Hawai‘i, USA. Open Access Aquatic Microbial Ecology, 87 . pp. 167-183. DOI 10.3354/ame01977.

[thumbnail of a087p167.pdf]
Preview
Text
a087p167.pdf - Published Version
Available under License Creative Commons: Attribution 4.0.

Download (2MB) | Preview
[thumbnail of CTD data from the +P mesocosm] Other (CTD data from the +P mesocosm)
a087p167_supp.xlsx - Supplemental Material
Available under License Creative Commons: Attribution 4.0.

Download (484kB)

Supplementary data:

Abstract

A large-volume mesocosm-based nutrient perturbation experiment was conducted off the island of Hawai‘I, USA, to investigate the response of surface ocean phytoplankton communities to nutrient addition of macronutrients, trace metals, and vitamins and to assess the feasibility of using mesocosms in the open ocean. Three free-drifting mesocosms (~60 m3) were deployed: one mesocosm served as a control (no nutrient amendments), a second (termed +P) was amended with nitrate (N), silicate (Si), phosphate (P) and a trace metal + vitamin mixture, and a third (termed -P) was amended with N, Si, and a trace metal + vitamin mixture but no P. These mesocosms were unreplicated due to logistical constraints and hence differences between treatments are qualitative. After 6 d, the largest response of the phytoplankton community was observed in the +P mesocosm where chlorophyll a (chl a) and 14C-based primary production were 2–3× greater than the -P mesocosm and 4–6× greater than the control. Comparison between mesocosm and ‘microcosm’ incubations (20 l) revealed differences in the magnitude and timing of production and marked differences in community structure with a reduced response of diatoms in microcosm treatments. Notably, we also observed pronounced declines in Prochlorococcus populations in all treatments: although these were greater in microcosms (up to 99%). Overall, this study confirmed the feasibility of deploying free-drifting mesocosms in the open ocean as a potentially powerful tool to investigate ecological impacts of nutrient perturbations and constitutes a valuable first step towards scaling plankton manipulation experiments.

Document Type: Article
Keywords: Phytoplankton; Nutrient dynamics; Mesocosm; North Pacific Subtropical Gyre
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BI Biological Oceanography
Main POF Topic: PT6: Marine Life
Refereed: Yes
Open Access Journal?: No
Publisher: Inter Research
Date Deposited: 05 Jan 2022 13:09
Last Modified: 07 Feb 2024 15:44
URI: https://oceanrep.geomar.de/id/eprint/54710

Actions (login required)

View Item View Item