Temporal change in zooplankton communities in Ligurian SeaTwo decades in comparison

UNIVERSITÀ DEGLI STUDI DI GENOVAFacoltà di Scienze Matematiche, Fisiche e NaturaliCorso di Laurea in Scienze del Mare

CandidateLuca Stirnimann

SupervisorsProf. Paolo Povero

Dr. Alessandra Conversi

Prof. Giorgio Bavestrello

Portofino – Ligurian Sea

Sea Surface Temperatures in Ligurian Sea (Cattaneo-Vietti et al., 2015)

Water column temperature in Station LTER-PF - DISTAV

Annual Winter Spring Summer Autumn -

0.20

0.40

0.60

0.80

1.00

1.20

chlro

phyl

l-a (µ

g L-

1)

1987-1994 (Light grey) 2000-11 (Dark grey)

1985-1995Licandro & Ibanez

(2000)

Site C

2003-2014DISTAV

Site LTER - PF

Purpose

The comparison had the purpose of determining any changes in the

mesozooplankton structure and in the trophic network

Sampling plan1985-1995

Site CLicandro &

Ibanez (2000)

2003-2014 Site LTER – PF

DiSTAV

Depth site 80 m 85 m

Column sampled 0 – 60 m 0 – 50 m

Instrument Bongo 335 µm

WP2/Bongo 200 µm

Materials and methods

Skjoldal et al. Progress in Oceanography 108 (2013) 1–42

400 µm

300 µm

200 µm+ 100%

+ 50% + 50%

Max dimension < 1 mm

Medium little and little size

Max dimension > 1mm

medium and big size

Classe dimensionale Taxa Ind/m3/anno %

G Appendicularia, Thaliacea, Chaetognatha, Cnidaria 18,86 18,4

M Copepoda 69,90 68,1MP Copepoda 6,39 6,2P Cladocera 7,54 7,3

102,68 100,0

Sito C 1985-1995Classe dimensionale Taxa Ind/m3/anno %

G Appendicularia, Thaliacea, Chaetognatha, Cnidaria 94,35 23,3

M Copepoda 100,90 24,9MP Copepoda 180,39 44,5P Cladocera 29,32 7,2

404,97 100,0

Sito LTER - PF 2003-2014

Sito C 1985-1995 Sito LTER - PF 2003-20140

50100150200250300350400450

PMP MG

Ind/

m3 L

MLMB

Total abundance for each size class

12.13%

51.79%20.70%

15.38%Sito LTER - PF 2003-2014

9.40%

73.41%

6.81%10.39%

Sito C 1985-1995

CarnivorousDetritivoresSospensivorusHerbivores and Onnivores

Trophic web changes

Fritilla

ria sp

p.

Doliolum

spp.

Salpid

ae

Sagit

ta spp

.

Sipho

noph

ora

Acartia

clausi

Centro

page

s typ

icus

Isias c

lavipe

s

Temora

stylif

era

Nanno

calan

us mino

r

Classe

B

Oithon

a sim

ilis

Evad

ne sp

inifera

Oncaea

spp.

Parac

alanu

s parv

us

Corycae

us spp

.

Classe

C

Oikople

ura sp

p.

Podo

n spp

.

Hydroz

oa0

102030405060708090

Average annual abundances

Station C 1985-1995 Station LTER - PF 2003-2014

Ind/

m3

Friedman Test - p<0.05

Gen Feb Mar Apr Mag Giu Lug Ago Set Ott Nov Dic0

102030405060708090

Oikopleura spp.

Sito C

Sito LTER - PF in

d m

-3

Gen Feb Mar Apr Mag Giu Lug Ago Set Ott Nov Dic0

50

100

150

200

250Paracalanus parvus

Sito C

Sito LTER-PF in

d m

-3

Some conclusions• Sospensivor gelatinous are

increasing like Oikopleura spp. • Detritivores are really increasing?The temperature increase is going to

change the quality and quantity mesozooplankton community?

The comparision was based on Skjoldal et al.

There are some problems about this:• Studies in Bering Sea• Different net meshes• Not enough data for to create a good

correction index

These were only some of the results obtained.

The complexity of the comparison and the problems found leads me to increase the studies and to start new research projects

to finish it.