MEPS 499:35-46 (2014)  -  DOI: https://doi.org/10.3354/meps10668

Coupling between upper ocean layer variability and size-fractionated phytoplankton in a non-nutrient-limited environment

Pablo Sangrà1,*, Cristina García-Muñoz2, Carlos M. García3, Ángeles Marrero-Díaz4, Cristina Sobrino5, Beatriz Mouriño-Carballido5, Borja Aguiar-González4, Cristian Henríquez-Pastene6, Ángel Rodríguez-Santana4, Luis M. Lubián2, Mónica Hernández-Arencibia4, Santiago Hernández-León1, Elsa Vázquez5, Sheila N. Estrada-Allis4

1Instituto Universitario de Oceanografía y Cambio Global, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Spain
2Departamento de Ecología y Gestión Costera, Instituto de Ciencias Marinas de Andalucía (ICMAN-CSIC), 11510 Puerto Real, Cádiz, Spain
3Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
4Departamento de Física, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Spain
5Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, 36200 Vigo, Pontevedra, Spain
6Departamento de Geofísica, Universidad de Concepciín, 160-C Concepcíon, Chile
*Corresponding author:

ABSTRACT: We describe the coupling between upper ocean layer variability and size-fractionated phytoplankton distribution in the non-nutrient-limited Bransfield Strait region (BS) of Antarctica. For this purpose we use hydrographic and size-fractionated chlorophyll a data from a transect that crossed 2 fronts and an eddy, together with data from 3 stations located in a deeply mixed region, the Antarctic Sound (AS). In the BS transect, small phytoplankton (<20 µm equivalent spherical diameter [ESD]) accounted for 80% of total chl a and their distribution appeared to be linked to cross-frontal variability. On the deepening upper mixed layer (UML) sides of both fronts we observed a deep subducting column-like structure of small phytoplankton biomass. On the shoaling UML sides of both fronts, where there were signs of restratification, we observed a local shallow maximum of small phytoplankton biomass. We propose that this observed phytoplankton distribution may be a response to the development of frontal vertical circulation cells. In the deep, turbulent environment of the AS, larger phytoplankton (>20 µm ESD) accounted for 80% of total chl a. The proportion of large phytoplankton increases as the depth of the upper mixed layer (ZUML), and the corresponding rate of vertical mixing, increases. We hypothesize that this change in phytoplankton composition with varying ZUML is related to the competition for light, and results from modification of the light regime caused by vertical mixing.


KEY WORDS: Physical-biological coupling · Mesoscale · Submesoscale · Vertical mixing · Phytoplankton composition · Antarctica


Full text in pdf format  
Cite this article as: Sangrà P, García-Muñoz C, García CM, Marrero-Díaz Á and others (2014) Coupling between upper ocean layer variability and size-fractionated phytoplankton in a non-nutrient-limited environment. Mar Ecol Prog Ser 499:35-46. https://doi.org/10.3354/meps10668

Export citation
Mail this link - Contents Mailing Lists - RSS
- -