Toward predicting Dinophysis blooms off NW Iberia: A decade of events

Ma Teresa Moita; Yolanda Pazos; Carlos Rocha; Rita Nolasco; Paulo B Oliveira

doi:10.1016/j.hal.2015.12.002

Toward predicting Dinophysis blooms off NW Iberia: A decade of events

Harmful Algae. 2016 Mar:53:17-32. doi: 10.1016/j.hal.2015.12.002. Epub 2016 May 3.

Authors

Ma Teresa Moita¹, Yolanda Pazos², Carlos Rocha³, Rita Nolasco³, Paulo B Oliveira⁴

Affiliations

¹ Instituto Português do Mar e da Atmosfera (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-165 Lisboa, Portugal; CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-339 Faro, Portugal. Electronic address: tmoita@ipma.pt.
² Instituto Tecnolóxico para o Control do Medio Mariño, Peirao de Vilaxoán, s/n, 36611 Vilagarcía de Arousa, Spain.
³ CESAM e Departamento de Física da Universidade de Aveiro, 3810-193 Aveiro, Portugal.
⁴ Instituto Português do Mar e da Atmosfera (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-165 Lisboa, Portugal. Electronic address: pboliveira@ipma.pt.

PMID: 28073442
DOI: 10.1016/j.hal.2015.12.002

Abstract

Dinophysis acuminata and Dinophysis acuta are recurrent species off NW Iberia but their outbreaks occur under different conditions. A decade (2004-2013) of weekly data for each species at two sentinel stations located at the entrance of Rias de Aveiro-AV (NW Portugal, 40°38.6'N) and Pontevedra-PO (Galicia, Spain, 42°21.5'N), were used to investigate the regional synchronism and mesoscale differences related to species detection, bloom (>200cellsL^-1) initiation and development. Results highlight the high interannual variability of bloom events and summarize the associated meteorological/oceanographic conditions. D. acuta blooms were observed in 2004-2008 and 2013, and the species highest maxima at AV occurred after the highest maxima of its prey Mesodinium, with a time-lag of 2-3 weeks. D. acuminata blooms were observed every year at both stations. The cell concentration time series shows that the blooms generally present a sequence starting in March with D. acuminata in PO and three weeks later in AV, followed by D. acuta that starts at AV and three months later in PO. Exceptionally, D. acuminata blooms occurred earlier at AV than PO, namely in high spring upwelling (2007) or river runoff (2010) years. A four-year gap (2009-2012) of D. acuta blooms occurred after an anomalous 2008 autumn with intense upwelling which is interpreted as the result of an equatorward displacement of the population core. Numerical model solutions are used to analyze monthly alongshore current anomalies and test transport hypotheses for selected events. The results show a strong interannual variability in the poleward/equatorward currents associated with changes in upwelling forcing winds, the advection of D. acuta blooms from AV to PO and the possibility that D. acuminata blooms at AV might result from inocula advected southward from PO. However, the sensitivity of the results to vertical position of the lagrangian tracers call for more studies on species distribution at the various bloom stages.

Keywords: Harmful algal blooms; Interannual variability; Meteorological anomalies; Shelf circulation; Upwelling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Dinoflagellida / physiology*
Environmental Monitoring / methods*
Models, Biological*
Oceanography
Phytoplankton
Portugal
Seawater
Spain
Wind