Impact of ENSO oceanographic variability in the nano- and microphytoplankton dynamics off central coast of Peru – 12° S (2013-2017)

Avy N. Bernales, Sonia Sánchez, Michelle Graco, Elcira Delgado, Jesús Ledesma, Flor Chang, Nelly Jacobo, Diana Alvites, Luc Beaufort and David Correa.

Project: “Integrated study of coastal upwelling off central Peru”

April 24-26, 2018

INTRODUCTION

Messié and Chavez, 2015

Mann & Lazier, 2006

INTRODUCTION

More abundance More diversity

Microphytoplankton (20 - 300 µm) Nanophytoplankton (2 – 20 µm)

Nitrate (µmol /L)

N:P>5 N:P<1

Oceanographic setting

Trade winds weaken, supressing the upwelling

SST ANOMALIES (°C)

STUDY AREA METHODOLOGY

Shelf break

25

1309

Estaciones

80

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0

50 40 30 20 10 0nautical miles (nm)

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Sampling stations

2 7 5

Sampling period: 2013-2017 Sampling frequency: bimonthly Coverage: Up to 50 nm from the

coast

OBJECTIVES

Characterize the nano and microphytoplankton community

structure in a gradient in shore – off shore in front of Callao (12° S) in space and time. Evaluate the influence of environmental parameters in the

composition and distribution of phytoplankton, identifying posible habitat preferences by key species. Identify possible phytoplankton assemblages or key species

of a transition zone.

Sampling with oceanographic rosette at 10 m depth and/or in water column up to 75 m.

Quantitative analysis (Utermöhl) Shannon index diversity Statistical analysis -Olmstead and Tukey diagram - Spatial and temporal classification and ordination (PRIMER 6 and R)

METHODOLOGY

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Station 7 (50 nm)

DIATOMS DINOFLAGELLATES SILICOFLAGELLATES COCCOLITHOPHORIDS PHYTOFLAGELLATES Total Phytoplankton

R E S U L T S

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Dinoflagellates7 5 2 7 5 2

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Vertical distribution

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Dep

th (m

)

7 5 2 Coccolithophorids

50 40 30 20 10 0 (nm)

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60 50 40 30 20 10 0 (nm)

Phytoflagellates

50 40 30 20 10 0 (nm)

7 5 2

RESULTS Obtaining phytoplankton species hierarchy

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Ln (∑

abso

lute

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sity)

Frequency %

Dominants

Ocasionals

Rares

Constants

Olmstead y Tukey diagram of micro and nanophytoplankton species off Callao (2013-2017)

• 189 species were obtained by Utermöhl method.

• They were classified in

diagram to perform multivariate analysis then.

• 61 dominant species were determined

C: Coastal (8 nm) I: Intermediate (30 nm) O: Oceanic (50 nm)

Spatial Clustering and Canonical correspondence analysis (CCA) showing the distribution of dominant phytoplankton species in relation to environmental variables

RESULTS

(14

%)

(25 %)

D pum Nitz sp.

O. hid

L und P mic

(11 %)

(9 %

)

Temporal Clustering and Canonical correspondence analysis (CCA) showing the ocurrence of dominant phytoplankton species in relation to environmental

variables

RESULTS

4 main phytoplankton assemblages were obtained

RESULTS

Improving coccolithophorids sampling !

Estacionesst1 st2 st3 st4 st5 st6 st7

stock

total

(x10

3 cell/L

)

0

20

40

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180mean abundance

X -43.80 x103 cel/L

Coastal area offshore

Alvites D. 2016. MsC Thesis (Graco M. L. Beaufort). Frontiers El Niño 2018

Coccolithophorids

ADVANCES Upwelling Low pH/high CO2

Composition and abundance of coccolithophorids

Ophiaster spp.

Helicosphaera carteri Calcidiscus leptoporus

Florisphaera profunda Gephyrocapsa oceanica

Emiliania huxleyi

Otros: Acanthoica quatrospina Anoplosolenia brasiliensis Calciosolenia sp. Calciopappus rigidus Gaardelia corolla Michaelsarsia adriaticus Pappomonas sp. Type 3 Polycrater sp. Reticulofenestra parvula Syracosphaera anthos Syracosphaera prolongata Syracosphaera molischii

CONCLUSIONS

There was a gradient in shore- off shore in all years, except in 2015 due warmer EN event conditions.

There is a variable transition zone at 30 nm that is favourable for dinoflagellates and coccolithophorids development.

Seasonal and interannual oceanographic influence (annual cycle of phytoplankton and ENSO signal) is reflected in the high variability of abundances and contributions of nano and microphytoplankton.

Ecological preferences were determined for D. pumila, Nitzschia sp, O. hidroideus, L. undulatum and P.micans.

Thank you for the financial support to :