Difference between revisions of "Template:This weeks featured article"

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''' Salinity sensors '''
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''' Fisheries in Blankenberge '''
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[[Image: electrode_conductivity.JPG | 300px| thumb |right| Electrode Conductivity principle]]
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Belgium has a minor role in the European fisheries context with 0.35% of the total EU production of fish. In 2012, the Belgian commercial sea fishing fleet counted 86 ships, with a total engine capacity of 49,135 kW and gross tonnage of 15,326 GT. 45 vessels are part of the Small Fleet Segment (max 221 kW engine power) of which 2 use passive gear. The remaining 41 vessels belong to the Large Fleet Segment and have an engine power between 221 kW and a maximum of 1,200 kW. This fleet segment represents approximately 80% of the engine power capacity and 77% of the GT of the fleet. While a smaller number use trammel nets (passive gear) and otter trawl, the largest share of the Large Fleet Segment are beam trawl vessels (≥662 kW). The Belgian fleet is highly specialized: more than 68% of the effort(days at sea) and 77% of total landings are achieved by beam trawlers (2010) focusing primarily on flatfish species such as plaice (''Pleuronectes platessa'') and sole (''Solea solea''). The results of the reconstruction of the Belgian fleet dynamics since 1830 are presented in Lescrauwaet et al. 2013.
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Since as far as Ancient Greece times, attempts have been made to try to measure the "saltiness" of seawater. However, methods' efficiency was very incipient and their sensitivity and repeatability was very limited. During the Modern History more precise methodologies were developed: weighing after evaporation (Boyle,1693; Birch, 1965), solvent extraction (Lavoisier, 1772) and precipitation (Bergman, 1784).  
 
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In 1865, Forchhammer introduced the term salinity and dedicated himself to measure individual components of seasalt rather than the total salinity. He found that the ratio of major salts in samples of seawater from various locations was constant.  
 
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Salinity is a ratio and not a physical parameter that can be measured(under PSS-78, see box). Thus, “Salinity sensors” do not exist. What is commonly referred to as a salinity sensor is in fact a conductivity sensor.
 

Revision as of 11:31, 8 October 2014

Fisheries in Blankenberge Belgium has a minor role in the European fisheries context with 0.35% of the total EU production of fish. In 2012, the Belgian commercial sea fishing fleet counted 86 ships, with a total engine capacity of 49,135 kW and gross tonnage of 15,326 GT. 45 vessels are part of the Small Fleet Segment (max 221 kW engine power) of which 2 use passive gear. The remaining 41 vessels belong to the Large Fleet Segment and have an engine power between 221 kW and a maximum of 1,200 kW. This fleet segment represents approximately 80% of the engine power capacity and 77% of the GT of the fleet. While a smaller number use trammel nets (passive gear) and otter trawl, the largest share of the Large Fleet Segment are beam trawl vessels (≥662 kW). The Belgian fleet is highly specialized: more than 68% of the effort(days at sea) and 77% of total landings are achieved by beam trawlers (2010) focusing primarily on flatfish species such as plaice (Pleuronectes platessa) and sole (Solea solea). The results of the reconstruction of the Belgian fleet dynamics since 1830 are presented in Lescrauwaet et al. 2013.

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