Commerson’s dolphins

On January 25, 2019 By ClaireIn Cetacean, Discovery DY098, WildlifeLeave a comment

Commerson’s dolphins are mainly found in very shallow, coastal waters around Argentina, the Falkland Islands and the Straits of Magellan. Since this is the first time I’ve been this far South myself, I’ve been very much looking forward to seeing them.

I was not disappointed!

Their colour pattern is striking – and the white patches make them really easy to see, even through the greenish coastal waters. As we wait on the ship making final preparations are made to leave, these wonderful little dolphins are regular visitors. To readers back in Scotland who are more familiar with the robust bottlenose dolphins we have around the East Coast, these will seem very tiny indeed – they average only about 150cm long.

They tend to live in small groups – we are seeing them most commonly in pairs and threes – and feed on a variety of different small fish species. They’re a generalist predator.

I’m slightly wishing I had a hydrophone on this trip as it would be great to get a recording of them to hear how they sound.

Photo credits – Simon Pinder

The Wandering albatross

On January 23, 2019January 24, 2019 By ClaireIn Discovery DY098, Guest post, Seabirds, Wildlife2 Comments

Guest post by Simon Pinder

With a three-and-a-half metre wing-span a wandering albatross effortlessly soars ten metres above the waves. Utilising the wind currents, it can then glide 200 metres without expending energy to rise up over the next peak in the swell. Using this method wandering albatrosses soar around the southern oceans, covering huge distances efficiently. A tagged wandering albatross was recorded covering 6000km in 12 days.

Wandering and royal albatrosses, the great albatrosses, have the largest wingspan of any bird in the world. They breed on Sub-Antarctic islands for example South Georgia, nesting on platforms constructed of vegetation and earth. The female lays one huge white egg which is incubated for about 80 days, after the chick hatches it is fed by both parents who undertake marathon feeding trips to provision it. After almost ten months of its lonely vigil on the nest it is ready to take to the air, it will not return to land until it too is ready to breed. By then it will have circumnavigated the globe for up to 15 years.

Wandering albatross. Photo (C) S. Pinder

The albatrosses use the strong westerly winds of the roaring forties and the furious fifties way down in the southern hemisphere where land is scarce and the winds build in their uninterrupted passage around the world. The females and young males spend their time in the relative calm of the forties, but the older males, those over 40 years old, live in without competition in the fifties where the stronger wings aid their ageing wings.

One of the effects of climate change is a change in the world’s weather patterns; with more chaos in the system, windier places can become windier. This can pose problems for scientists in the field as windier, rougher seas can be difficult to work on. However, the greater force of these increased winds has allowed wandering albatrosses to travel faster and therefore spend more time foraging. As a consequence, they have become fitter and heavier*. Whether in the future this will result in even larger birds or an over-exploitation of resources is currently unknown.

Simon is a freelance ornithologist and marine mammal surveyor, based in Scotland.

* Weimerskirch, H. et al., 2012. Changes in Wind Pattern Alter Albatross Distribution and Life-History Traits. Science. 335. 211. DOI: 10.1126/science.1210270

Storm petrels

On January 23, 2019January 23, 2019 By ClaireIn Discovery DY098, Guest post, Seabirds, WildlifeLeave a comment

Black-bellied and Wilson’s storm petrel. Guest post by Simon Pinder

Dragging its leg through the water, pattering its feet across the swell, bouncing over the wave tops storm petrels spend almost their entire time at sea within touching distance of the ocean’s surface.

Storm petrels are very small seabirds weighing (30-60g). They feed on tiny animals in the surface plankton dipping in to this biological soup, sometimes shallowly plunging just below the waves.

Wilson’s petrel hopping along the water surface. Photo (C) S. Pinder

Wilson’s petrels follow ships for hours feasting food stirred up by the vessel’s passage. They shadow whales for the same reason, benefiting from the whale’s movements to bring plankton within their shallow reach. They are often found alongside other seabirds, such as giant petrels and albatrosses, feeding on the remains of predated penguins and fur seals successfully hunted by killer whales and leopard seals.

Black-bellied storm petrel dragging it’s foot across the surface. Photo (C) S. Pinder

Black-bellied storm petrels search areas with seemingly random twists and turns, frequently dragging their leg across the sea’s surface as they pivot and zigzag, seizing tiny fish and other inhabitants of the plankton.

They return to land under the cover darkness to visit their single chick hidden in burrows on Sub-Antarctic islands, both nesting on South Georgia.

Could you spot the difference from a moving ship? Wilson’s storm petrel (top) and black-bellied storm petrel (bottom). Photo (C) S. Pinder

Simon is a freelance ornithologist and marine mammal surveyor, based in Scotland.

A day on the RRS Discovery…

On January 22, 2019January 22, 2019 By ClaireIn Discovery DY098, Guest post, Science1 Comment

Guest post by Megan Sørensen

It’s 5am and for the scientists on the early shift it’s time for their day to begin. This includes the scientists who are recording the whales and dolphins they see. They spend the day standing outside on the top deck with their binoculars, cameras and warm layers. Also up at this time are the scientists who have to keep an eye on the overall survey measurements, this means checking a screen that displays everything that the ship passes over and reads all the way to the sea floor, which is over 3km down!

A couple of hours later it’s breakfast, and the scientists on ‘normal’ days are also up and about. These scientists might be running their own experiments in the labs using samples that we’ve already collected. Someone might be on the microscope identifying some of the tiny organisms that live in the sea, and there are probably some people studying krill in the cold lab (set to 2°c so you need all your layers on if you’re working in here).

Then it’s lunch time and the ship starts to get busy as the people from yesterday’s night shift are now awake too. Meal times are important and sometimes they are the only time when everyone comes together. It’s also nice because the crew, scientists, and engineers all sit together. The ship crew keep the entire ship running – from steering the ship, looking after the engines and cooking – and nothing could be done without them.

In the late afternoon we see the change over from the day to night shift in the main lab. The people who started early are now finishing, while the night shift has only just got started. For the engineers and scientists on the night shift their main job is using the different types of nets to take samples from the ocean. We do this to monitor how the different species change year to year, and whether this is impacted by variation in the environment or changes in fishing laws. The samples we take are only small and can only take small creatures – mostly krill, jellyfish, and some small fish. The night shift can last till 3 or 4 am and requires a lot of coffee to see it through.

After that the ship is quiet for an hour or two before the early morning shift starts and it all begins all over again.

Megan Sørensen is a PhD student at the University of Sheffield, studying as part of the BBSRC White Rose DTP Program. For more information on her work, please contact @MESSorensen on twitter

Guest Post – Louise Cornwall

On January 22, 2019January 22, 2019 By ClaireIn Discovery DY098, Guest post, ScienceLeave a comment

Plankton are critical components of the marine ecosystem. There are two groups of plankton, the “phyto” (plant) and “zoo” (animal)-plankton. Both phyto- and zooplankton transfer energy through the food web to larger animals, such as penguins, seals, dolphins and whales. This means it is important we understand how marine plankton respond to future climate change scenarios, as this could have major impact on the whole marine ecosystem. My work concentrates on two components of climate change. The first is the rapid increase in ocean temperature. The second is a process called Ocean Acidification. Increasing levels of carbon dioxide (CO₂) in the atmosphere are causing the ocean to become more acidic. These two components, both separately or combined, are proven to be harmful to various marine life.

I study a certain type of zooplanktonic animal called a copepod. Copepods are very small crustaceans, generally less than 2 mm in length. They are the most abundant type of zooplankton in the world’s oceans. My aim is to increase our knowledge of how these tiny, but very important, animals cope under climate change.

Copepod seen through a microscope… not easy when the floor, desk and everything else are moving in a rough sea!

During the Discovery cruise, I am collecting copepods from plankton net hauls. Once caught, they are stored for at least 12 hours in order to acclimatise. I then exposed them to different environmental conditions:

“normal” – seawater matches natural environment.
“high temperature” – seawater temperature is increased.
“acidification” – seawater acidity is increased.
“high temperature + acidification” – both seawater temperature and acidity are increased.

How copepods, and plankton as a whole, respond to climate change will impact entire marine ecosystems. A better understanding of these responses will increase our ability to predict the future of our oceans.

Louise Cornwall is a Phd Student at Plymouth Marine Laboratory. For more information on her work, email loco@pml.ac.uk

Adventures in whale counting

Category: Discovery DY098