scholarly journals Effect of ocean warming and acidification on a plankton community in the NW Mediterranean Sea

2014 ◽  
Vol 72 (6) ◽  
pp. 1744-1755 ◽  
Author(s):  
L. Maugendre ◽  
J.-P. Gattuso ◽  
J. Louis ◽  
A. de Kluijver ◽  
S. Marro ◽  
...  

Abstract The effect of ocean warming and acidification was investigated on a natural plankton assemblage from an oligotrophic area, the bay of Villefranche (NW Mediterranean Sea). The assemblage was sampled in March 2012 and exposed to the following four treatments for 12 days: control (∼360 μatm, 14°C), elevated pCO2 (∼610 μatm, 14°C), elevated temperature (∼410 μatm, 17°C), and elevated pCO2 and temperature (∼690 μatm, 17°C). Nutrients were already depleted at the beginning of the experiment and the concentrations of chlorophyll a (chl a), heterotrophic prokaryotes and viruses decreased, under all treatments, throughout the experiment. There were no statistically significant effects of ocean warming and acidification, whether in isolation or combined, on the concentrations of nutrients, particulate organic matter, chl a and most of the photosynthetic pigments. Furthermore, 13C labelling showed that the carbon transfer rates from 13C-sodium bicarbonate into particulate organic carbon were not affected by seawater warming nor acidification. Rates of gross primary production followed the general decreasing trend of chl a concentrations and were significantly higher under elevated temperature, an effect exacerbated when combined to elevated pCO2 level. In contrast to the other algal groups, the picophytoplankton population (cyanobacteria, mostly Synechococcus) increased throughout the experiment and was more abundant in the warmer treatment though to a lesser extent when combined to high pCO2 level. These results suggest that under nutrient-depleted conditions in the Mediterranean Sea, ocean acidification has a very limited impact on the plankton community and that small species will benefit from warming with a potential decrease of the export and energy transfer to higher trophic levels.

2009 ◽  
Vol 6 (3) ◽  
pp. 453-461 ◽  
Author(s):  
V. Andersen ◽  
M. Goutx ◽  
L. Prieur ◽  
J. R. Dolan

Abstract. In the framework of the PROOF-PECHE project (http://www.obs-vlfr.fr/proof/vt/op/ec/peche/pec.htm) a multi-disciplinary team performed experiments and collected samples during the DYNAPROC 2 cruise aboard the RV Thalassa from September to October in 2004. The cruise provided data on the functioning of the pelagic food web by sampling over a month long period in the NW Mediterranean Sea at a fixed station subject to weak horizontal advection currents during a period of hydrological stability. This paper describes the background of the cruise and provides an overview of the results derived from the campaign which constitute the special section. The major objective of the cruise was to assess the relative importance and variability of the pathways of carbon in the open ocean. Intensive sampling through 4 periods of 5 days each was accomplished at a site near the DYFAMED time-series site. The site was near stable in terms of hydrodynamics as there was some evidence of an intrusion of low-salinity coastal water. The cruise yielded a comprehensive data set acquired by sampling over a vertical spatial dimension (0–1000 m) and at high frequencies (ranging from every 3, 6, 12 and/or 24 h), unique for the summer to autumn transition in the North Western Mediterranean. Parameters investigated included the biochemical composition of dissolved organic matter (lipids), and the structure of bacterial communities, phytoplankton and zooplankton community compositions and abundances, as well as zooplankton metabolism, and particulate organic carbon fluxes. Nearly all the parameters described in this section, as well as reports appearing elsewhere, showed time-course variabilities of similar magnitude to those known from a previous study of the spring-summer seasonal transition, a period of marked hydrological change, at the same study site. Remarkably, the least variable characteristic of the system appeared to be the identities of the dominant taxa across several trophic levels (copepods, phytoplankton, ciliates, and bacteria) throughout the study period despite large shifts in stock sizes and fluxes. Thus, the studies of DYNAPROC 2 documented considerable temporal variability of stocks and rates in a system which was, from a hydrological and taxonomic point of view, relatively stable.


2020 ◽  
pp. 105227
Author(s):  
Elena Lloret-Lloret ◽  
Maria Grazia Pennino ◽  
Daniel Vilas ◽  
José María Bellido ◽  
Joan Navarro ◽  
...  

2013 ◽  
Vol 118 ◽  
pp. 81-94 ◽  
Author(s):  
Catalina Pasqual ◽  
Miguel A. Goñi ◽  
Tommaso Tesi ◽  
Anna Sanchez-Vidal ◽  
Antoni Calafat ◽  
...  

2012 ◽  
Vol 77 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Pierre Sabatier ◽  
Laurent Dezileau ◽  
Christophe Colin ◽  
Louis Briqueu ◽  
Frédéric Bouchette ◽  
...  

A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300–6100, 5650–5400, 4400–4050, 3650–3200, 2800–2600, 1950–1400 and 400–50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150–650 cal yr BP) was characterised by low storm activity.The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain.


2012 ◽  
Vol 168 ◽  
pp. 87-95 ◽  
Author(s):  
Joan A. Salvadó ◽  
Joan O. Grimalt ◽  
Jordi F. López ◽  
Xavier Durrieu de Madron ◽  
Serge Heussner ◽  
...  

2008 ◽  
Vol 153 (1) ◽  
pp. 157-168 ◽  
Author(s):  
Izaskun Zorita ◽  
Maren Ortiz-Zarragoitia ◽  
Itxaso Apraiz ◽  
Ibon Cancio ◽  
Amaia Orbea ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Fernando Gómez ◽  
Alf Skovgaard

Dinoflagellate infections have been reported for different protistan and animal hosts. We report, for the first time, the association between a dinoflagellate parasite and a rotifer host, tentativelySynchaetasp. (Rotifera), collected from the port of Valencia, NW Mediterranean Sea. The rotifer contained a sporangium with 100–200 thecate dinospores that develop synchronically through palintomic sporogenesis. This undescribed dinoflagellate forms a new and divergent fast-evolved lineage that branches among the dinokaryotic dinoflagellates.


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