H. Botnen’s scientific contributions

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Publications (5)


Species Richness and Invasion Vectors: Sampling Techniques and Biases
  • Article

December 2003

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31 Reads

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38 Citations

Biological Invasions

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H. Rosenthal

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H. Botnen

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During a European Union Concerted Action study on species introductions, an intercalibration workshop on ship ballast water sampling techniques considered various phytoplankton and zooplankton sampling methods. For the first time, all the techniques presently in use worldwide were compared using a plankton tower as a model ballast tank spiked with the brine shrimp and oyster larvae while phytoplankton samples were taken simultaneously in the field (Helgoland Harbour, Germany). Three cone-shaped and 11 non-cone shaped plankton nets of different sizes and designs were employed. Net lengths varied from 50 to 300 cm, diameters 9.7–50 cm, and mesh sizes 10–100 μm. Three pumps, a Ruttner sampler, and a bucket previously used in ballast water sampling studies were also compared. This first assessment indicates that for sampling ballast water a wide range of techniques may be needed. Each method showed different results in efficiency and it is unlikely that any of the methods will sample all taxa. Although several methods proved to be valid elements of a hypothetical `tool box' of effective ship sampling techniques. The Ruttner water sampler and the pump P30 provide suitable means for the quantitative phytoplankton sampling, whereas other pumps prevailed during the qualitative trial. Pump P15 and cone-shaped nets were the best methods used for quantitative zooplankton sampling. It is recommended that a further exercise involving a wider range of taxa be examined in a larger series of mesocosms in conjunction with promising treatment measures for managing ballast water.


Figure 1. Number of identified taxa according to number of sampled ships (all shipping studies). 3.3 OTHER TAXA (BACTERIA, FUNGI AND PROTOZOANS) 
Table 1 . Number of ships sampled, number of samples and duration of shipping studies carried out in European countries.
Figure 2. Species, including species with unconfirmed identification (species cf.) of the flora (a) (total number of taxa 497), fauna (b) (total number of taxa 425), and bacteria, protozoa and fungi, summarised as "other taxa" (c) identified during all European shipping studies. Specimens that could not be ascribed to a genus level, were assigned to the lowest appropriate taxonomic unit (Family, Order etc.) summarised here as "higher taxa" with the addition "indet.". 
Figure 3. Bray-Curtis similarity analysis based on studies that collected fauna in ballast water. Species found in sediment samples are omitted unless they were found both in sediment and water samples (Abbreviations see Table A1). 
Table 4 . Fauna: Number of taxa identified during European shipping studies according to higher taxonomic unit. Crustacea broken down in taxonomic groups.

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Life in ballast tanks. pp. 217-231
  • Article
  • Full-text available

January 2002

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522 Reads

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34 Citations

The abundance and diversity of species in ballast water, a recognised vector for the accidental introduction of nonindigenous organisms, has been examined through many studies around the world over the last 25 years. The results of European research activities are summarised in this contribution by outlining the objectives of some of these studies, and by focusing on the diversity of taxa determined from ballast water and tank sediment samples. In total 1508 samples (1219 ballast water, 289 tank sediment) were collected on 550 ships. A total of 990 taxa were identified during the 14 European shipping studies. The diversity of species found included bacteria, fungi, protozoans, algae, invertebrates of different life stages including resting stages, and fishes with a body length up to 15 cm. Crustacean, molluscan and polychaete invertebrates and algae form the majority of species found.

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Life in Ballast Tanks

January 2002

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100 Reads

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106 Citations

The abundance and diversity of species in ballast water, a recognised vector for the accidental introduction of nonindigenous organisms, has been examined through many studies around the world over the last 25 years. The results of European research activities are summarised in this contribution by outlining the objectives of some of these studies, and by focusing on the diversity of taxa determined from ballast water and tank sediment samples. In total 1508 samples (1219 ballast water, 289 tank sediment) were collected on 550 ships. A total of 990 taxa were identified during the 14 European shipping studies. The diversity of species found included bacteria, fungi, protozoans, algae, invertebrates of different life stages including resting stages, and fishes with a body length up to 15 cm. Crustacean, molluscan and polychaete invertebrates and algae form the majority of species found.


Fluctuations of Zooplankton Taxa in Ballast Waterduring Short-Term and Long-Term Ocean-Going Voyages

November 2000

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60 Reads

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83 Citations

Internationale Revue der gesamten Hydrobiologie und Hydrographie

A major vector for unintentional species introductions is international shipping. A wide range of organisms have been transported over long distances in ships' ballast tanks and as hull fouling. Although many desk studies and ship sampling programmes have been carried out, little information is available on changing numbers of individuals in ballast water during voyages. Detailed information could assist in evaluating the dimension of species import and future risks of unintentional species introductions by ballast water. The first European study, organised as a concerted action team and financed by the European Union, carried out several long-term and short-term workshops on board ships undertaking international voyages. The preliminary results from sampling the ballast water of the first four oceangoing workshops of this Concerted Action showed a decrease in numbers of specimens and taxa over time.


Citations (5)


... In addition, the specimen was captured near the major commercial port of Gijón, where not only have non-native species been previously n recorded (Cabal et al., 2006), but also where merchant vessels from the species´range had docked in the weeks prior to the capture (personal communication, Port Authority of Gijón). Ballast water from ships is a significant transport vector of non-native and invasive aquatic species (Gollasch et al., 2002). In the eastern Atlantic, ballast water has been identified out as a mechanism for the arrival of several native fishes from the western Atlantic, including Micropogonias undulatus (Linnaeus, 1766) (Stevens et al., 2004), Trinectes maculatus (Bloch & Schneider, 1801) (Wolff, 2005) and Cynoscion regalis (Bloch and Schneider, 1801) (Morais & Teodósio, 2016;Bañón et al., 2018). ...

Reference:

First record of Diapterus brevirostris (Teleostei: Gerridae) in Atlantic European waters: a case of introduced species
Life in ballast tanks. pp. 217-231

... A genetic approach was used for studying resting eggs in ship ballast water, a pathway recognised as a potential dispersal mechanism for plankton since the late 1890s [39]. A large number of cladocerans are able to survive in ballast sediments [12]. Now resting eggs of water fleas are detected in ballast waters by molecular methods [184,185]; it is confirmed this mechanism is the main vector of inter-continental introductions of the Cladocera, and that domestic shipping is a way of their further dispersal [186]. ...

Life in Ballast Tanks
  • Citing Chapter
  • January 2002

... The concentration of viable zooplankton organisms observed is in a similar range as documented in other ballast water studies considering ballast water uptake sampling (Lavoie et al. 1999;Gollasch et al. 2000;Olenin et al. 2000;McCollin et al. 2007bMcCollin et al. , 2008Simard et al. 2011;Maranda et al. 2013;Briski et al. 2015). ...

Fluctuations of Zooplankton Taxa in Ballast Waterduring Short-Term and Long-Term Ocean-Going Voyages
  • Citing Article
  • November 2000

Internationale Revue der gesamten Hydrobiologie und Hydrographie

... Findings of larger organisms in ballast tanks do therefore indicate that species were either pumped on board as eggs or younger larvae and were growing inside a tank, or that reproduction has possibly even occured inside a ballast tank. In fact, Gollasch, Rosenthal, et al. (2000) found by daily samplings of the same ballast tank on an approximately 3-week voyage an increasing number of copepods in a tank and they concluded that reproduction occurred inside the tank during this voyage. ...

Survival rates of species in ballast water during international voyages: Results of the first workshops of the European Union Concerted Action

... For indicative in-tank sampling, it was concluded that sampling for zooplankton via the sounding pipes does not result in a representative sample of species in the tank, as comparisons of sounding pipe and manhole samples from the same tank found that net samples taken via manholes delivered more biologically diverse samples (Sutton et al. 1998;Gollasch et al. 2000). Further, pumps used via open manholes delivered more diverse samples than net samples, therefore pumps may also be considered when sampling via manholes (Sutton et al. 1998;Gollasch et al. 2003). A problem is Fig. 2 Vessel selection process for BWM CME, including the initial and the detailed inspection elements. ...

Species Richness and Invasion Vectors: Sampling Techniques and Biases
  • Citing Article
  • December 2003

Biological Invasions