Category Archives: HYPNO

Fieldwork with the SponGES project on R/V Kristine Bonnevie – part II

I wanted to write a bit more abou the SponGES cruise, as we are currently entering Sognefjorden on the second spring cruise Luis and I have managed to sign up for (what a job!).

SponGES took us to Korsfjorden, Bømlafjorden, west of Bømlahuken and finally past Fedje and back to Bergen. We ended up with ~70 stations, using grabs, Agassiz trawl, plankton net, RP-sledge and ROV. For the most part the gear performed admirably, though we had some mishaps (and an epic final station, key word being MUD – Anne Helene will have more to say about that one).
The first grab of the new cruise is going down, so I have to be quick; here’s SponGES in pictures (not recorded: lots of laughs and horrible songs)

: Call that a sponge? Now THIS is a sponge!

: Pretty, pretty Norway!

: True stowaway – (s)he hitchhiked to Bergen after blowing onboard

: Fancy slugs

: The awesome student team – you guys did great!

: Plankton net going out

: Can’t ask for calmer waters

: Sieving in the sunset

: How gorgeous is this?

: Sorting trawl catch on deck

: All smiles, even in the spicules

: Many, many buckets

: Well fed! (both us and the catch!)

: Tomopteris polychates from the plankton catch

: Gorgonocephalus

: Fedje

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

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

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

Sertularella gayi

-Luis

Fieldwork with the SponGES project on R/V Kristine Bonnevie

Greetings from the big, old blue!

We don’t have much internet out here, so updates will be sporadic – but here’s the tale of the first half of the two cruises that the Invertebrate Collections people have stowed away on this spring. The current cruise is part of the SponGES-project that is being coordinated by the University of Bergen, Norway (prof. Hans Tore Rapp).

We are currently midway in the six-day cruise (26^th of April to 2^nd of May), and are presently to be found at 59°63,000 N, 04°42,000 E – there are mountains on one horizon, and open ocean on the other. After a night of muddy (clay-y) sampling, the majority of us are relaxing and eagerly awaiting lunch, whilst some of the sponge-folks are huddled inside the big, blue container on the deck, surveying the sea floor with the ROV Aglantha (occasionally cherry-picking sponges with fancy scoops).

The ROV Aglantha, inside the Blue Box, and sponge-capturing device

At present we are at station #33; it has been three busy days so far! This is the first trip for all of us on the “new” R/V Kristine Bonnevie (formerly known as “Dr. Fritjof Nansen”, but that name has passed on to the new Nansen vessel), and we’re thoroughly enjoying it. The crew is amazing, the food is delicious, and the samples keep coming – what’s not to like? Even the weather has been good to us most of the time – though we have sprouted quite a crop of anti-seasickness patches onboard by now!

#bestoffice

We had to take a break to admire this

Shenanigans on deck

In addition to the ROV, we are using van Veen grabs, Agassiz trawl, plankton net, and RP-sledge to collect fauna. We also stumbled across hundreds of meters of lost fishing line when diving with Aglantha – the operators were able to catch an end of it, and it was dragged onboard to be discarded properly. The rope was heavily colonized by sponges, hydrozoa and mussels, so we got a “bonus sample” from that – and we got to clear away some marine pollution. Win/win!

Old Fishing line being removed – and samples taken from it!

My main incentive for being onboard is to secure ethanol-fixed (=suitable for DNA work) material from locations that we have either none or only formaldehyde fixed. This will then become part of the museum collections – and we will have fresh material for DNA barcoding through NorBOL.

Ready to dive in!

The art of washing grab samples – get rid of the mud, keep the animals intact!

Scooping up top sediment from grabs for analyses

Incoming trawl

Sampling in the sunset

The samples we are collecting are gently and carefully treated on deck before being bulk (i.e. unsorted) fixated in ethanol. There is lab space onboard, but we don’t have the time to do much sorting here. It will be exciting to see what we find once we get back to the lab and begin sorting it!

Lab facilities onboard

But before we get to that, we have three more days with SponGES, and then we go on to the next cruise, which will also be with Bonnevie – this time we’re heading up and into the Sognefjord.

Stay tuned for updates!

-Katrine

ps: SponGES’ facebook page is here

Door #12: All aboard the jelly cruise!

Travelling alone through the water column may be a dangerous business: reaching the final destination is not always guaranteed, the risk of being eaten is high, and even finding food may prove a difficult task… which is why several animals choose to travel comfortably on or inside jellyfish and siphonophores!

Jellyfish are commonly involved in relationships of parasitism and phoresis (i. e., when one organism is mechanically transported by another without any further physiological dependence), and many examples have been observed of these interactions around the world. For instance, it’s not unusual to find hyperiid amphipods and sea-spiders –as well as lobster and crab larvae – piggybacking on the surface of large and tiny jellyfish, and while it’s still not clear whether or not all these passengers feed on their means of transportation, real parasitism and jelly-feeding has been confirmed for at least some of them. Jellyfish may also transport parasitic worms to their final hosts (like the nematode you see in the pictures), acting as carriers of parasites towards fish and mammals, and sometimes, eventually reaching humans as well!

Euphysa aurata medusa with parasitic nematode larva. Korsfjord, February 2016. Credit: Aino Hosia.

A close-up of 2 showing the parasite embedded in the mesoglea (jelly) of the host. Credit: Aino Hosia.

Euphysa aurata medusa with crustacean ectosymbiont. Raunefjord, December 2016. Credit: Luis Martell

These two hydromedusae of Euphysa aurata were collected this year in the fjords south of Bergen, and are only an example of jellyfish harboring other animals in this area. The species is a common and widespread jellyfish around here, but its role in the transmission of parasites and transportation of small crustaceans has never been explored. It might well be that, together with its gelatinous relatives, E. aurata will prove to be involved in many more biological interactions than we previously thought!

Luis Martell

Door #10: Siphonophores

Today, I thought I’d introduce to you to a cool group of animals that is ubiquitous in the oceans (including the Norwegian seas), but unfamiliar to most people. Siphonophores (“kolonimaneter” in Norwegian) belong to cnidarians, a group that includes corals, anemones, hydroids and jellyfish, and is characterized by the presence of stinging cells used in prey capture. All siphonophores are predatory, and use their stinging tentacles to catch small crustaceans or, in the case of some species, even small fish.

The most (or only) familiar siphonophore for the majority of people is probably the highly venomous Portuguese Man O’War (Physalia physalis), which can be spotted floating on the surface of the ocean or stranded on beaches. However, it is not really representative of the group as a whole, as most siphonophores live in the water column of the open ocean rather than its surface. There are around 200 described species of siphonophores.

The most fascinating feature of siphonophores is their peculiar body plan. While siphonophores may appear to be a single animal, they are in fact a colony of physiologically connected and genetically identical but morphologically diverse individuals called zooids that have specialized to carry out different tasks for the colony. Siphonophores belong to the class Hydrozoa (“polyppdyr” in Norwegian), which covers two basic body plans: the polyp/hydroid and the medusa.

Schematic of a physonect siphonophore. From http://www.siphonophores.org (CC-by-nc-sa)

The various zooids comprising a siphonophore colony can also be divided into these main groups. For example, the zooids used for swimming, called nectophores, are medusoid, while the feeding zooids, or gastrozooids, are polyp-like. The siphonophore colony can also include specialized defensive, protective and reproductive zooids. All the zooids forming a colony arise by budding from a single fertilized egg. The different zooids are specialized to the degree that they cannot function as individual animals any more, and are only able to perform their specific tasks as parts of the siphonophore colony.

Anterior nectophore, posterior nectophore and eudoxid of the calycophoran siphonophore Dimophyes arctica – a common species in Norwegian waters. Photos by Aino Hosia (cc-by-sa)

The zooids, for example the swimming nectophores, vary in appearance between species, and can be used for species identification. In addition, the various types of zooids in the colony are arranged in a strict species specific pattern, providing the intact colonies of each species with their particular appearance. While the individual zooids are generally small, millimeters to centimeters in size, some siphonophore species, like Praya dubia, may have colonies that reach 40 m in length! Siphonophore colonies generally have a zone of one or more (up to several dozen) swimming nectophores at the front, used to pull the colony through water. Behind this nectosome is the siphosome, which contains the feeding, reproductive and other zooids in a repeating pattern, each iteration of which is called a cormidium. In some species (suborder Calycophorae), these cormidia are released as small free-living reproductive colonies called eudoxids. Unfortunately, siphonophore colonies are extremely fragile and tend to fall apart during standard plankton sampling with nets, leaving behind a bewildering array of small bits and pieces – part of the reason they are relatively poorly known to most people.

Colony of physonect siphonophore Physophora hydrostatica, aka hula skirt siphonophore. Photo by Aino Hosia (cc-by-sa)

Intact siphonophore colonies are beautiful, but often utterly alien in appearance. It is interesting to consider where to draw the line between an individual and a colony. While we as individuals have specialized organs to carry out our various bodily functions, siphonophore colonies are made up of specialized interdependent individuals or zooids similarly carrying out their specific tasks.

As part of project HYPNO we are charting the diversity of pelagic hydrozoans, including siphonophores, in Norway. There are ~15 species observed in Norwegian waters, and some, particularly Dimophyes arctica, Lensia conoidea and Nanomia sp. are extremely common components of marine plankton. However, siphonophores are primarily noticed when they become a nuisance: For example, mass occurrences of Muggiaea atlantica and Apolemia uvaria have in the past killed large numbers of farmed fish in Norway, with resulting losses to aquaculture companies.

– Aino (HYPNO)

Intrigued by siphonophores? For more information, visit e.g. http://www.siphonophores.org/ by Casey Dunn.

Door #12: Plankton sampling with a vertebrate view!

HYPNO participating on an Arctic cruise by the Institute of Marine Research on RV Helmer Hanssen 17 Aug – 7 Sep 2015.

Most of the pelagic hydrozoans for HYPNO are collected with simple plankton nets, in the case of this Arctic cruise the double one you see in the picture. The net is towed vertically from above the bottom to the surface, bringing with it a representative sample of plankton – inclusive hydromedusae and siphonophores – from the entire water column. Standard plankton nets are generally lowered and retrieved at a speed of ~0.5 ms^-1.

This particular station in the Arctic basin was over 2000 m deep, which means that a single tow takes more than an hour to complete. Sometimes waiting for the sample to come up can get a bit tedious – not at this station, though! With this beauty turning up right outside the hangar opening, the wait didn’t feel long at all!

-Aino

The Invertebrate Collections

The University Museum of Bergen