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Physico-chemical and biological characteristics of the Blanes site.

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Presentation on theme: "Physico-chemical and biological characteristics of the Blanes site."— Presentation transcript:

1 Physico-chemical and biological characteristics of the Blanes site

2 Sampling site Sampling site Half mile from Blanes harbour, depth of 20 m Parameters to be collected Vertical profiles of temperature and salinity Seawater for nutrients, pigments, electron microscopy, flow cytometry, picoeukaryal isolations and DNA extraction

3 General characteristics of Blanes Bay Typical Mediterranean waters: warm, salty and nutrient-poor Blanes Bay: oligotrophic coastal waters (annual average chlorophyll of 0.87 µg l -1 ) Less affected by human influence than systems closer to the Barcelona area (70 km south) Relatively large data set from other projects

4 Hydrography Front in the continental slope (generally miles offshore) that separates coastal from oceanic waters. There is an associated current flowing southwest This current can be deflected near the Blanes canyon, causing episodic intrusions of oceanic waters near the coast

5 General currents Surface drifter 5 days in May 1992

6 Climate Climate Temperate system with strong climate fluctuations Unimodal seasonality only for temperature; most other forcing factors show a much complex variance structure Minves de gener: winter period of high pressure and low sea level that allows a phytoplankton bloom (2-4 weeks) Strong influence of episodic rain storms

7 Temperature Minimum in late January to March (11-12°C), maximum in August-September (25-26°C) Thermocline from May-June to September-October

8 Salinity Range from 37(coastal waters) to 38.4 (open-sea waters), with episodic intrusions of lower salinity waters (down to 32) from the Rhone river plume or rainfall

9 Nutrients Relatively low and highly variable Two-year average (in µmol l -1 ): 1.18 ammonium 0.11 nitrite 0.96 nitrate 0.29 phosphate

10 Seasonality of phytoplankton Main peak of chlorophyll a during late winter, driven by high atmospheric pressures together with irradiances and temperatures higher than similar latitudes in the Atlantic Smaller peaks in early fall

11 Average biovolume of phytoplankton Picoeukaryotes: 29% in % in Cyanobacteria: 7% in % in Centric diatoms dominate in the winter and fall peaks, whereas dinoflagellates dominate in summer

12 Seasonality of other microbial components Bacteria Flagellates Ciliates

13 Related projects CEAB sampling in Blanes ( ) ICM sampling in Blanes (and other coastal sites) in 1998 Hivern cruises in the Catalan Sea. February 1999 and 2000 ARO cruise in the Catalan Sea. June 2000 Next cruise above the Blanes canyon in May 2001

14 CEAB sampling in Blanes High periodicity from 1992 to 1997 (at least once a week) Parameters measured Metereology: rain, irradiance, sea level, wave action Surface temperature and salinity Biomass of bacteria, protists, algae and zooplankton Primary production, community respiration

15 ICM sampling in three coastal sites Barcelona, Masnou and Blanes plus Barcelona harbour Once a month during Fractions µm and µm Parameters measured Surface temperature Fractionated chlorphyll a, bacteria and picophytoplankton Samples for environmental DNA


17 Seasonal succession of bacterioplankton in Blanes DGGE with primers Bact338f and Un907r

18 Bacterial succession

19 ANT12 Jan February March Apr Jun Jul Sep Oct Nov Dec Seasonal succession of picoeukaryotes in Blanes DGGE with primers Euk1f and Euk516r

20 26 MARCH MARCH ---- | MARCH | | +-- | | 29 APRIL | | | | | | | 3 MARCH --- | | | | +-- | | | 25 FEBRUARY --- | | | | | +-- | | | 5 FEBRUARY | | | | 27 JANUARY | DECEMBER | | 3 SEPTEMBER | | | +-- | | 4 NOVEMBER | | | +--- | | 3 JUNE | | JULY | | 29 JULY | | OCTOBER Summer and Fall Winter and Spring Picoeukaryal succession in Blanes

21 Spatial differences of bacterial assemblages in three coastal sites

22 Spatial differences in some coastal systems Summer Winter Spring

23 Summary of Blanes site Oligotrophic coastal system with weak human influence Episodic intrusions on oceanic waters near the coast and strong effect of rain storms on water-column conditions Unimodal seasonality only in surface temperature Most important phytoplankton bloom in late winter Temporal succession of most groups studied, including bacteria and picoeukaryotes

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