ORIGINAL RESEARCH published: 27 March 2019 doi: 10.3389/fmars.2019.00145 Spatio-Temporal Pattern of Dinoflagellates Along the Tropical Eastern Pacific Coast (Ecuador) Gladys Torres 1, Olga Carnicer 2*, Antonio Canepa 3, Patricia De La Fuente 4, Sonia Recalde 1, Richard Narea 1, Edwin Pinto 1 and Mercy J. Borbor-Córdova 5 1 Instituto Oceanográfico de la Armada del Ecuador, Guayaquil, Ecuador, 2 Escuela de Gestión Ambiental, Pontificia Universidad Católica del Ecuador Sede Esmeraldas (PUCESE), Esmeraldas, Ecuador, 3 Escuela Politécnica Superior, Universidad de Burgos, Burgos, Spain, 4 Institut de Ciències del Mar, CSIC, Barcelona, Spain, 5 Escuela Superior Politécnica del Litoral (ESPOL), Facultad de Ingeniería Marítima y Ciencias del Mar, Guayaquil, Ecuador Among marine phytoplankton, dinoflagellates are a key component in marine ecosystems as primary producers. Some species synthesize toxins, associated with human seafood poisoning, and mortality in marine organisms. Thus, there is a large necessity to understand the role of environmental variables in dinoflagellates spatial- temporal patterns in response to future climate scenarios. In that sense, a monthly four-year (2013–2017) monitoring was taken to evaluate dinoflagellates abundances and physical-chemical parameters in the water column at different depths. Sampling Edited by: sites were established at 10 miles in four locations within the Ecuadorian coast. Jorge I. Mardones, A total of 102 taxa were identified, corresponding to 8 orders, 22 families, and 31 Instituto de Fomento Pesquero genera. Eight potentially harmful genera were registered but no massive blooms were (IFOP), Chile detected. The most frequent dinoflagellates were Gymnodinium sp . and Gyrodinium Reviewed by: Sai Elangovan S, sp . Environmental variables showed different mixing layer thickness and a conspicuous National Institute of Oceanography and deepening thermocline/oxycline/halocline and nutricline depending on annual and (CSIR), India Punyasloke Bhadury, seasonal oceanographic fluctuations. This study confirms that seasonal and spatial Indian Institute of Science Education distribution of the environmental variables are linked to the main current systems on the and Research Kolkata, India Eastern Tropical Pacific, thus the warm Panama current lead to a less dinoflagellates *Correspondence: abundance in the north of Ecuador (Esmeraldas), while the Equatorial Upwelling and Olga Carnicer [email protected] the cold nutrient-rich Humboldt Current influence dinoflagellates abundance at the central (Manta, La Libertad) and South of Ecuador (Puerto Bolivar), respectively. Inter- Specialty section: annual variability of dinoflagellates abundance is associated with ENSO and upwelling This article was submitted to Marine Ecosystem Ecology, conditions. Climate change scenarios predict an increase in water surface temperature a section of the journal and extreme events frequency in tropical areas, so it is crucial to involve policy-makers Frontiers in Marine Science and stakeholders in the implementation of future laws involving long-term monitoring Received: 10 September 2018 Accepted: 07 March 2019 and sanitary programs, not covered at present. Published: 27 March 2019 Keywords: dinoflagellates, HABs, ENSO, tropical Eastern Pacific, nutrients, upwelling, humboldt current Citation: Torres G, Carnicer O, Canepa A, De La Fuente P, Recalde S, Narea R, INTRODUCTION Pinto E and Borbor-Córdova MJ (2019) Spatio-Temporal Pattern of Dinoflagellates Along the Tropical The Equatorial Pacific region is characterized by a unique complex oceanographic variability with Eastern Pacific Coast (Ecuador). a well-defined Equatorial Front where El Niño Southern Oscillation (ENSO) events eventually Front. Mar. Sci. 6:145. occur ( Santos, 2006 ; Gierach et al., 2012 ). The Ecuadorian coast is divided in two biogeographical doi: 10.3389/fmars.2019.00145 regions, a northern “Bay of Panama” ecoregion from Azuero Peninsula to Bahía de Caráquez and a Frontiers in Marine Science | www.frontiersin.org 1 March 2019 | Volume 6 | Article 145 Torres et al. Dinoflagellates in Ecuador southern “Guayaquil” ecoregion from Bahía de Caráquez to the Torres (2015) observed the presence of algal proliferations along Illescas peninsula in Perú ( Sullivan and Bustamante, 1999 ). The the Ecuadorian coast, which were more frequent in the Gulf northern coast of Ecuador is influenced by the warm current of Guayaquil, where most aquaculture activities are located. of Panama and the current of El Niño, while the Humboldt Therefore, through the analysis of the INOCAR data bases, current brings cold water to the southern Ecuadorian coast this study aims to provide information related to dinoflagellates which contributes to outcrops formation in the area ( Cucalon, abundances dynamic across a broad latitudinal area from 2013 to 1989 ). The southern sector is the most productive area regarding 2017 that constitute a base-line for future investigations. fisheries and shrimp production ( Pennington et al., 2006 ). Due to the variability found in oceanographic conditions over the Ecuadorian coast, there is a noticeable heterogeneity concerning MATERIALS AND METHODS physical, chemical, and biological parameters which leads to a high diversity in phytoplankton communities ( Smayda, 2008 ) Study Area and Samples Collection and the potential formation of harmful algae blooms (HABs). The study area was located between 0 ◦89 North and 03 ◦036 The oceanographic conditions identified as drivers of HABs, South, in the ETP Ocean. Along the study area, four geographic are linked to those conditions associated to upwelling systems points were settled as sampling stations: three of them located (cold nutrient-rich waters), high column water stratification 10 miles from the coast : (1) Esmeraldas (Galera San Francisco), (mostly associated to ENSO conditions), and long-term sea (2) Manta, (3) La Libertad (Santa Elena Peninsula), and (4) surface temperature (SST) increase due to climate change Puerto Bolívar ( Figure 1 ). All stations have an approximate (Hallegraeff, 2010 ; McCabe et al., 2016 ; Kudela et al., 2017 ). Those depth of 100 m. except for Puerto Bolívar station, which is studies that have related the particular oceanographic conditions located approximately 27 miles, inside the submarine platform with the occurrence of HABs in the Pacific Ocean ( Brown in a pit that is 9 m deep, northeast of Santa Clara Island in the et al., 2003 ; Franco-Gordo et al., 2004 ; Moore et al., 2010 ), have Gulf of Guayaquil. shown that those factors module the phytoplankton community At each sampling station, 200 mL water samples were collected and dynamics. In general, the phytoplankton community on in plastic bottles from surface, 10, 20, 30, 40, 50, and 75 m the Eastern Tropical Pacific (ETP) region is characterized by depth using a 3 Liter volume Vand Dorn bottle, then preserved relatively low levels of biomass, with the dominance of small in neutral Lugol’s solution (final concentration 0.4%). Samplings species and rare large bloom-forming diatoms ( Brown et al., were performed monthly from February 2013 to December 2017, 2003 ). Diatoms and dinoflagellates are two major groups of between 09h00 to 12h00 am. phytoplankton that flourish in the oceans ( Abate et al., 2017 ), mostly registered in the south-eastern Equatorial Front ( Jimenez- Phytoplankton Identification and Bonilla, 1980 ; Torres and Tapia, 2002 ), and upwelling systems Abundance Estimation (Shulman et al., 2012 ). Particularly, dinoflagellates exhibit environmentally induced adaptation and survival to changing Water samples were settled in 25 mL volume Utermöhl chambers environmental conditions ( Kudela et al., 2010 ). (Utermöhl, 1958 ), and observed in a Leica (ML) inverted Among the dinoflagellate community, there are some toxin microscope after 24 h. Cell abundance estimation was performed producer dinoflagellates which may impact negatively marine in horizontal transects of the chamber at 400 × magnification. −1 ecosystems causing massive marine organism mortality, cause Results are reported in cell. L . The validity of names of the economic damage in coastal locations and affect human health by different taxa was checked on the World Register of Marine seafood consumption ( Li et al., 2014 ). In addition, ballast waters Species ( Horton et al., 2018 ). Dinoflagellate species identification contribute to the transfer of phytoplankton in commercial and oil was based on Steidinger and Jangen (1997); Hoppenrath et al. tankers resulting in the dispersion of non-native phytoplankton (2009)Hoppenrath et al. (2014); Omura et al. (2012) , and species, increasing the risk of phytoplankton proliferation Lassus et al. (2016) . The list of toxic species was checked (Hallegraeff, 2003 ). Moreover, physiological changes may affect on the Taxonomic Reference List of Harmful Micro Algae phytoplankton communities in response to climate change (Moestrup et al., 2009 ). (Poloczanska et al., 2016 ) with consequences in their distribution In Esmeraldas and Puerto Bolívar no sampling was performed and abundances worldwide. In that sense, it is important during February to December 2016 due to economic issues. to perform studies related to phytoplankton biodiversity characterization and its spatio-temporal variability to guarantee Environmental Variables an optimal integrated coastal management, contributing to future Temperature and salinity vertical profiles were obtained using decisions from policy-makers to optimize waters vigilance. a SBE 19plus V2 SeaCAT Profiler CTD,