Year Of Plankton

This year we have launched a Year Of Plankton, an initiative to share interesting plankton facts and photos to help build your plankton knowhow! On this page you will be able to find the latest entry for the week, as well as all entries from previous weeks, in case you missed out. 

Week 11 - Spring bloom

Did you know the oceans experience spring too?

During winter, rough seas increase mixing of the water column, re-suspending nutrients and phytoplankton cysts (resting stages of phytoplankton).

As spring arrives, with longer days and increasing light and temperature levels, diatoms like these are able to reproduce rapidly, leading to an event known as the spring bloom.

 

Although these organisms are microscopic, spring blooms can often be seen from space!

Week 10 - Tripos arcticus

Tripos arcticus is a cold water phytoplankton species from the Genus Tripos.

This species can bloom in very high numbers during winter months as they not only photosynthesise, like a plant, but also ingest smaller organisms too, like an animal.

During these blooms, T. arcticus can reproduce so rapidly the colour of the water can change to a reddish/brown colour, and in extreme cases, oxygen levels can become depleted, an event known as a Harmful Algal Bloom.

Week 9 - Calanus hyperboreus

Meet the deep water copepod, Calanus hyperboreus, an animal which dominates the Arctic Ocean in number.

 

It grazes on algae growing on the underside of the sea ice and on free-floating phytoplankton, and is sometimes referred to as the “little cow of the ocean”.

These food sources are important to help it maintain a high fat content, to help sustain it through the long dark winters.

In the Arctic, fats are the currency of life, and these copepods form the primary food source for many larger marine species, including Arctic cod.

Week 8 - Branchiostoma lanceolatum

These fish-like animals are called Lancelets and the closest living relatives of all vertebrates

Their body is supported by a primitive back-bone called a notochord, which prevents their bodies collapsing as they swim.

Scientists have been studying these animals as it’s believed they hold many clues to the evolution and development of all living vertebrates!

The most well-known representative from this group is the Branchiostoma lanceolatum, as seen in these pictures.

Week 7 - Pterosperma

Pterosperma are recorded in the CPR Survey in their non-mobile cyst, or phycoma, stage, and look very similar to little flying saucers when viewed from above. They can be identified by their dense, inner structure, which can have single or multiple 'wings' or ala, often in circumference around the body.

Despite the species being poorly studied, it has been routinely recorded in the CPR Survey over the last few years and has an oceanic distribution in the North Atlantic, recorded throughout the year often during periods of high phytoplankton biomass (blooms).

Week 6 - Neodenticula seminae

The distinctive domino-like, chain-forming diatom Neodenticula seminae is considered the first plankton species to have made the crossing from the Pacific to the Atlantic Ocean via the increasingly ice-free Arctic. This species was last found in sediment records in the Atlantic from approx. 800,000 years ago. 

However, with the ice barrier reduced, a large volume of Pacific water first entered the Northwest Atlantic in summer 1998, carrying with it this diatom (there had been no shipping via this route, so ballast water transport has been dismissed). Since then the species has re-established itself across the northern North Atlantic.

Week 5 - Decapod megalopa

The crab equivalent of human teenage years is know as decapod megalopa! This name comes from the Latin meaning '10-footed' (Dec=10, pod=foot) referring to the 10 limbs all crabs have, and its stage 'megalopa' mega=big and lop=eyes, referring to the physical changes the crab goes through as it develops.

 

This megalopa stage is the final stage that occurs in the plankton, before the animal settles on to the sea floor and transforms into what we recognise as a crab.


 

Week 4 - Decapod zoea

Once thought to be separate species, we now know that zoea are juvenile stages of crabs, lobsters, crayfish, prawns + shrimp.

       

 Antonie van Leeuwenhoek, “The Father of Microbiology” was, in 1699, the first person to describe the differences between the larval stages of crustaceans and their adult forms. Despite this, controversy remained about whether or not metamorphosis occurred in crustaceans due to observations based on different species, some of which do not metamorphosise. This controversy persisted until the 1840s and it was not until the 1870s that the first complete series of descriptions of crustacean larval forms were published.


Week 3 - Miracia spp.

Juveniles of the brilliant blue copepod Miracia spp. have to cling for life on ‘rafts’ of blue green algae, namely the filamentous cyanobacteria Trichodesmium. In the open ocean suitable substrates for the development of Miracia spp. are scarce, and Trichodesmium provides both a source of food as well as being a floatation aid to kickstart their development.

  


 Week 2 - Noctiluca scintillans

When disturbed, these marine dinoflagellates (Noctiluca scintillans) glow, or bioluminesce – it’s easy to see why their common name is Sea Sparkle!

Unlike most dinoflagellates, N. scintillans do not feed via photosynthesis, instead they use their feeding tentacle to capture passing food such as diatoms and copepods! Check out their tentacles searching for food in this video clip! 

           


Week 1 - Cirripede

Did you know that before gluing themselves to rocks, juvenile barnacles begin life drifting in the plankton?

The early stage's of a barnacle's life include 2 free swimming stages, a nauplius and cypris stage, before they develop into adults and attach themselves to rocks.

Cirripede cypris  Cirripede nauplii      

Adult barnacles feed by pushing their feet through their 'trapdoor' roofs and waving them around to catch passing food! The last photo is of a barnacle exuvium - a complete exoskeleton an adult barnacle has shed in a moult - can you see the basket-like feeding limbs?

 Barnacle exuvium

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