Tag Archives: Hydrozoa

Sognefjorden cruise May 2017

After our week with SponGES on R/V Bonnevie, Luis and I had a night back in Bergen before we headed out on our second spring adventure: a four day cruise (still onboard Bonnevie) of Sognefjorden, the longest (205 km) and (deepest 1308 m) fjord in Norway.

The cruise, led by Prof. Henrik Glenner from the Institute of Biology, UoB,  was a multi-purpose one, with the majority of the projects being linked to the Norwegian Taxonomy Initiative (Artsprosjekt):

We collected material for the ongoing project that is investigating and mapping the barnacle fauna (Crustacea: Cirripedia) in Norway, which a special focus on the strange, parasitic barnacle Anelasma squalicola that is found on the shark Etmopterus spinax (velvet bellied lantern shark/svarthå).

The material we collected will also serve as an addendum to the project on Species inventory and nature type mapping of Sognefjorden, which was recently concluded.

As for the University Museum, Luis was onboard collecting pelagic and benthic Hydrozoa for the HYPNO-project, whilst I was on the hunt for more species for DNA-barcoding through NorBOL (the Norwegian Barcode of Life). We have also re-sampled some polychaete type localities from the 1970’s, and attempted to retrieve more material from stations where we have found new species in more recent material (we need more specimens before we can formally describe them).

In addition, we had two Danish researchers onboard that were studying the bioluminescence and eye development of the starfish family Brisingidae. The story told in images:

We should maybe also add "one of the most gorgeous" to the description of the fjord

We should maybe also add “one of the most gorgeous” to the description of the fjord

Velvet belly lanternshark, Etmopterus spinax

Velvet belly lanternshark, Etmopterus spinax

Henrik and Christoph sorting a shrimp trawl catch on deck

Henrik and Christoph sorting a shrimp trawl catch on deck

Eager pickings in the trawl catch

Eager pickings in the trawl catch

Not all trawl samples go according to plan... this one, taken in the open sea, ended up sampling *a bit* deeper than intended, so we got a lot of benthic animals - and mud. So. much. mud.

Not all trawl samples go according to plan… this one, taken in the open sea, ended up sampling *a bit* deeper than intended, so we got a lot of benthic animals – and mud. So. much. mud.

Most novel sampling gear yet? Collecting velvet belly lanternshark by monkfish!

Most novel sampling gear yet? Collecting velvet belly lanternshark by monkfish! (caught in the “benthic” trawl)

The brisinga sea stars are very fragile - and live deep down.

The brisinga sea stars are very fragile – and live deep down.

We amanged to get some not-too-damaged specimens with a small trawl

We manged to get some not-too-damaged specimens with a small trawl

The plankton net going our for collecting

The plankton net going our for collecting

Luis an Marie studying a plankton sample

Luis an Marie studying a plankton sample

Plankton

Plankton

For some reason, my samples seems to involve inordinate amounts of mud - good thing I had good helpers to work through it all!

For some reason, my samples seems to involve inordinate amounts of mud – good thing I had good helpers to work through it all!

Cruising in a postcard!

Cruising in a postcard!

Sadly, plastic pollution was prevalent in Sognefjorden as well - here's a soda bottle from a sample taken at 911 m depth

Sadly, plastic pollution was prevalent in Sognefjorden as well – here’s a soda bottle from a sample taken at 911 m depth

And here are som eof the plastic that we ended up with from our sampling, most of it from over 1000 meters depth.

Here is some of the plastic that we ended up with from our sampling, most of it recovered from over 1000 meters depth.

Our final night of the cruise was spent in the mud and the sunset - it's starting to become a recurring theme!

Our final night of the cruise was spent in the mud and the sunset – it’s starting to become a recurring theme!

Once again, thank you so much to the crew on Bonnevie for all their help!

Once again, thank you so much to the crew on Bonnevie for all their help!

-Katrine

Hunting for jellyfish (and some hydroids) with the SponGES Project

Picking out interesting specimens from the catch

Picking out interesting specimens from the catch

Any opportunity to be in the sea is a good opportunity to go jelly-hunting, and the recent participation of HYPNO on a research cruise with the SponGES Project on RV Kristine Bonnevie this late April – early May was no exception!

To begin with, we got the chance to sample some hydromedusae and siphonophores  with the plankton net in Bømlafjord. As usual, towing the net slowly (~0.3 ms-1) resulted in happy jellies (they get damaged if the net is towed too fast!) that sometimes can be identified with ease. Over 15 different species of pelagic hydrozoans (plus some ctenophores and Tomopteris worms) were present in this vertical tow, with some nice looking critters such as the Eutonina indicans and Leuckartiara octona medusae shown below.

Eutonina indicans

Eutonina indicans

Leuckartiara octona

Leuckartiara sp.

But not only hydromedusae and siphonophores showed up this time; we also got our hands on benthic samples from grabs and trawls, and found hydroids growing on rocks and other sea creatures (mostly sponges and sea squirts). Abietinaria abietina and Sertularella gayi (pictures below) are among the most common hydroids observed so far, and they were hosting a whole bunch of other hydrozoan species growing on top of them: real mini animal forests from the Norwegian waters!

Abietinaria abietina

Abietinaria abietina

Sertularella gayi

Sertularella gayi

 

-Luis

Door #3: Prepare to be HYPNOtized

One of this year’s new projects at the Invertebrate collections is HYPNO – Hydrozoan pelagic diversity in Norway, funded by the Norwegian Taxonomy Initiative.

A selection of photos depicting some of the species encountered so far in the project

A selection of photos depicting some of the species encountered so far in the project

Hydrozoa are a class of cnidarians, the pelagic representatives of which include hydromedusae as well as colonial siphonophores and porpitids. They are thus “cousins” to the more familiar larger scyphozoan jellyfish such as the moon jelly or the lion’s mane jelly. The size of pelagic hydrozoans ranges from small medusae of less than 1 mm to siphonophore colonies reaching several meters in length. They are mostly predators that use their tentacles and stinging cells to catch other zooplankton or even fish larvae. Most of the time they go largely unnoticed by the public, but at times they can form blooms and deplete zooplankton as well as cause problems for aquaculture and fisheries or sting bathers.

The aim of HYPNO is to chart, document and DNA-barcode the diversity of hydromedusae and siphonophores occurring in Norway. Gelatinous zooplankton, including hydrozoans, has been generally less studied than their crustacean counterparts, and we know less about their diversity. This is due to several challenges in studying them. First of all, many pelagic hydrozoans, particularly the colonial siphonophores, are very fragile and often damaged during sampling with standard plankton nets. This can make it difficult to identify them. Secondly, preserving hydromedusae and siphonophores for later work is problematic. For morphological studies, they are best preserved in formalin, since most other fixatives used for zooplankton -including ethanol- cause distortion and shrinkage of their gelatinous bodies, rendering the animals impossible to identify. Formalin fixation, however, hinders further genetic work.

To overcome these practical problems, HYPNO uses gentle collection methods to obtain specimens in good condition. Collected samples are immediately examined for hydrozoans, and the live animals are identified and documented with photos before they are fixed in ethanol for DNA barcoding of CO1 and 16S sequences.

So far, HYPNO has participated on two cruises by the Institute of Marine Research: to the North Sea and Skagerrak on RV Johan Hjort 24 Apr – 4 May 2015 and to the Arctic Ocean and Fram Strait on RV Helmer Hanssen 17 Aug – 7 Sep 2015. So far, 34 species have been photographed and sampled for DNA. Here is a selection of pictures depicting some of the species encountered during these surveys.

You can read more about HYPNO at http://data.artsdatabanken.no/Pages/168312.

-Aino