Short term changes in zooplankton community during the summer-autumn transition in the open NW Mediterranean Sea: species composition, abundance and diversity

Abstract. Short term changes in zooplankton community were investigated at a fixed station in offshore waters of the Ligurian Sea (DYNAPROC 2 cruise, September–October 2004). Mesozooplankton were sampled with vertical WP-II hauls (200 μm mesh-size) and large mesozooplankton, macrozooplankton and micronekton with a BIONESS multinet sampler (500 μm mesh-size). Temporal variations of total biomass, species composition and abundance of major taxa were studied. Intrusions of low salinity water masses were observed two times during the cruise. The first one, which was the most intense, was associated with changes in zooplankton community composition. Among copepods, the abundance of Calocalanus, Euchaeta, Heterorhabdus, Mesocalanus, Nannocalanus, Neocalanus, Pleuromammaand also calanoid copepodites increased markedly. Among non-copepod taxa, only small ostracods abundance increased. After this low salinity event, abundance of all taxa nearly returned to their initial values. The influence of salinity on each zooplankton taxon was confirmed by a statistical analysis (Perry's method). The Shannon diversity index, Pielou evenness and species richness were used to describe temporal variations of large copepod (>500 μm) diversity. The Shannon index and Pielou evenness decreased at the beginning of the low salinity water intrusions, but not species richness. We suggest that low salinity water masses contained its own zooplankton community and passed through the sampling area, thus causing a replacement of the zooplankton population.

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Short term changes in zooplankton community during the summer-autumn transition in the open NW Mediterranean Sea: species composition, abundance and diversity

Biogeosciences Discussions ◽

10.5194/bgd-5-2237-2008 ◽

2008 ◽

Vol 5 (3) ◽

pp. 2237-2278 ◽

Cited By ~ 4

Author(s):

V. Raybaud ◽

P. Nival ◽

L. Mousseau ◽

A. Gubanova ◽

D. Altukhov ◽

...

Keyword(s):

Species Richness ◽

Species Composition ◽

Zooplankton Community ◽

Mesh Size ◽

Temporal Variations ◽

Water Masses ◽

Short Term ◽

Low Salinity ◽

Low Salinity Water ◽

Salinity Water

Abstract. Short term changes in zooplankton community were investigated at a fixed station in offshore waters of the Ligurian Sea (Dynaproc 2 cruise, September–October 2004). Mesozooplankton was sampled with vertical WP2 hauls (200 µm mesh-size) and large mesozooplankton, macrozooplankton and micronekton with a BIONESS multinet sampler (500 µm mesh-size). Temporal variations of total biomass, species composition and abundance of major taxa were studied. Intrusions of low salinity water masses were observed two times during the cruise. The first one, which was the most important, was associated with changes in zooplankton community composition. Among copepods, the abundance of Calocalanus, Euchaeta, Heterorhabdus, Mesocalanus, Nannocalanus, Neocalanus, Pleuromamma and also calanoid copepodites increased markedly. Among non-copepod taxa, only small ostracods abundance increased. After this low salinity event, abundance of all taxa nearly returned to their initial values. The influence of salinity on each zooplankton taxon was confirmed by a statistical analysis (Perry's method). Shannon diversity index, Pielou evenness and species richness were used to describe temporal variations of large copepod (>500 µm) diversity. Shannon index and Pielou evenness decreased at the beginning of the low salinity water intrusions, but not species richness. We suggest that low salinity water masses contained its own zooplankton community and passed through the sampling area, thus causing the replacement of zooplankton population.

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Does the Mesh Size of the Plankton Net Affect the Result of Statistical Analyses of the Relationship Between the Copepod Community and Water Masses?

Crustaceana ◽

10.1163/001121611x586701 ◽

2011 ◽

Vol 84 (9) ◽

pp. 1069-1083 ◽

Cited By ~ 7

Author(s):

Chun-Ming Shin ◽

Kuo-Ping Chiang ◽

Chih-Jung Wu

Keyword(s):

Species Richness ◽

Species Composition ◽

Mesh Size ◽

Water Masses ◽

Statistical Analyses ◽

The East China Sea ◽

Copepod Community ◽

The Difference ◽

The Relationship ◽

Net Affect

AbstractWe examined if the results of statistical analyses of the relationship between copepod communities and water masses would be affected by the mesh size of the plankton net, by comparing abundance and species composition of copepods in plankton samples collected by plankton nets of different mesh sizes. Our samples were collected during the summer of 2006 in the East China Sea (ECS) by plankton nets with mesh sizes of 100 and 330 μm. The abundance of copepods collected by the 100 μm-mesh plankton net was about two orders of magnitude higher than that collected by the 330 μm-mesh plankton net. The difference in abundance was mainly due to the loss of small-sized copepods in the samples collected by the plankton net with the larger mesh. Species richness was higher in samples collected by the 100 μm-mesh net and Piélou's evenness was generally higher in samples collected by the 330 μm-mesh net. Although species composition of copepods varied in samples collected by plankton nets with different mesh sizes, the statistical analysis of the relationship between the copepod community and the water masses in these samples appeared not to be affected.

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