KOSMOS 2017 Peru mesocosm study: overview data

DOI

Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can mod- ify surface production and related biogeochemical processes. Determining these factors is important because EBUS are considered hotspots of climate change, and reliable predic- tions of their future functioning requires understanding of the mechanisms driving the biogeochemical cycles therein. In this field experiment, we used in situ mesocosms as tools to improve our mechanistic understanding of processes con- trolling organic matter cycling in the coastal Peruvian up- welling system. Eight mesocosms, each with a volume of ∼ 55 m3, were deployed for 50 d ∼ 6 km off Callao (12◦ S) during austral summer 2017, coinciding with a coastal El Niño phase. After mesocosm deployment, we collected sub- surface waters at two different locations in the regional oxy- gen minimum zone (OMZ) and injected these into four meso- cosms (mixing ratio ≈ 1.5 : 1 mesocosm: OMZ water). The focus of this paper is on temporal developments of organic matter production, export, and stoichiometry in the indi- vidual mesocosms. The mesocosm phytoplankton commu- nities were initially dominated by diatoms but shifted to- wards a pronounced dominance of the mixotrophic dinoflag- ellate (Akashiwo sanguinea) when inorganic nitrogen was exhausted in surface layers. The community shift coincided with a short-term increase in production during the A. san- guinea bloom, which left a pronounced imprint on organic matter C : N : P stoichiometry. However, C, N, and P export fluxes did not increase because A. sanguinea persisted in the water column and did not sink out during the experiment. Accordingly, export fluxes during the study were decou- pled from surface production and sustained by the remain- ing plankton community. Overall, biogeochemical pools and fluxes were surprisingly constant for most of the experiment. We explain this constancy by light limitation through self- shading by phytoplankton and by inorganic nitrogen limita- tion which constrained phytoplankton growth. Thus, gain and loss processes remained balanced and there were few oppor- tunities for blooms, which represents an event where the sys- tem becomes unbalanced. Overall, our mesocosm study re- vealed some key links between ecological and biogeochem- ical processes for one of the most economically important regions in the oceans.

Identifier
DOI https://doi.org/10.1594/PANGAEA.923395
Related Identifier IsSupplementTo https://doi.org/10.5194/bg-17-4831-2020
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.923395
Provenance
Creator Bach, Lennart Thomas ORCID logo; Paul, Allanah Joy ORCID logo; Boxhammer, Tim ORCID logo; von der Esch, Elisabeth; Graco, Michelle ORCID logo; Schulz, Kai Georg ORCID logo; Achterberg, Eric Pieter; Aguayo, Paulina; Arístegui Ruiz, Javier; Ayón, Patricia; Baños Cerón, Isabel; Bernales, Avy; Boegeholz, Anne Sophie; Chavez, Francisco P; Chen, Shao-Min ORCID logo; Doering, Kristin ORCID logo; Filella, Alba ORCID logo; Fischer, Martin A ORCID logo; Grasse, Patricia ORCID logo; Haunost, Mathias; Hennke, Jan; Hernández-Hernández, Nauzet ORCID logo; Hopwood, Mark James (ORCID: 0000-0002-9743-079X); Igarza, Maricarmen ORCID logo; Kalter, Verena; Kittu, Leila ORCID logo; Kohnert, Peter; Ledesma, Jesus ORCID logo; Lieberum, Christian; Lischka, Silke ORCID logo; Löscher, Carolin R ORCID logo; Ludwig, Andrea; Mendoza, Ursula; Meyer, Jana; Meyer, Judith; Minutolo, Fabrizio; Ortiz Cortes, Joaquin ORCID logo; Piiparinen, Jonna ORCID logo; Sforna, Claudia; Spilling, Kristian ORCID logo; Sanchez, Sonia; Spisla, Carsten; Sswat, Michael ORCID logo; Zavala Moreira, Mabel; Riebesell, Ulf (ORCID: 0000-0002-9442-452X)
Publisher PANGAEA
Publication Year 2020
Funding Reference German Research Foundation https://doi.org/10.13039/501100001659 Crossref Funder ID 27542298 https://gepris.dfg.de/gepris/projekt/27542298 Climate - Biogeochemistry Interactions in the Tropical Ocean
Rights Creative Commons Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Representation
Resource Type Dataset
Format text/tab-separated-values
Size 11 data points
Discipline Biogeochemistry; Biospheric Sciences; Geosciences; Natural Sciences
Spatial Coverage (-77.235 LON, -12.055 LAT)
Temporal Coverage Begin 2017-02-23T00:00:00Z
Temporal Coverage End 2017-04-10T00:00:00Z