Web Portal to Report Diseased Algae (Now closed)

The web portal My Seaweed Looks Weird (MSLW) which is now closed, was established within the framework of the GENIALG and Global Seaweed Star projects.

The Portal is no longer accepting samples. 

What was My Seaweed Looks Weird?

Diseased algae have always been around, but finding one of them in the wild is mostly a chance encounter. Often, the eye of beach-walkers is drawn by seaweeds with an unusual aspect (deformed growth, discolouration, galls, holes or rot symptoms, etc…), but such encounters usually go unreported. “My seaweed looks weird” was a platform where anyone could contribute weird-, or sad-looking seaweeds to accelerate research. With the marine environment undergoing very rapid changes worldwide, and in particular cultivation growing rapidly, we gathered a baseline of what diseases occurred where, both in the wild and in seaweed farms, in order to be able to detect and monitor any changes.

Our aim was to accelerate the description of algal diseases worldwide, by screening samples submitted by scientists, seaweed professionals or members of the public. We used the data to identify and map diseases, as well as describe novel or emerging issues. With time, we will make the results of this work available for free, through Open Access publications and a (yet-to-be-built) online disease atlas.

We have provided here a few examples of what diseases may look like, but let’s be honest that most diseases of algae are currently very poorly known. Using a combination of microscopy and potentially, DNA analysis, we endeavoured to send back a diagnosis in-kind for all samples received. For seaweed farmers, we provided a diagnosis for free, as and when they suspected problems.

Twisted stipe and galls on the stipe of Laminaria digitata

Outgrowths/galls/blisters on the blade of Palmaria palmata

Saccharina latissima showing discoloration, necrosis, hole and dark spot on the full blade

Symptoms of algae diseases

Algae diseases can be caused by two broad factors: environmental and pathogenic. The environmental diseases i.e. abiotic factors are non-infectious and include damage from poor or excessive illumination, freshwater dilution of seawater after heavy rainfall and nutritional deficiencies or toxicities of others algae boom (red/green tide). Algae diseases could be also caused by biotic factors like fishes and invertebrates, grazers feeding on the algae and causing loss of biomass. They could be also caused by many diverse pathogenic microbes: virus, bacteria, fungus, oomycetes, phytomyxeans or even other algal entophytes.

A symptom of algae disease is a visible effect of disease and can give a good clue about the type of pathogens involved. As for plants, symptoms could be a change in the shape or the colour of the alga as it responds to the pathogen even if it is not possible to actually seeing the pathogen himself.

Here are a few examples of common signs and symptoms of algae diseases how can affect different parts of the algae (holdfast, stipe, float/gas bladder, blade or the full front/thallus):

  • Blister
  • Discoloration spot
  • Black spot
  • Bleaching (whitening)
  • Hole
  • Malformation and twisted frond
  • Twisted stipe
  • Gall

What did we do with the samples?

Using a combination of microscopy and potentially DNA analysis, we endeavoured to send back an in-kind diagnosis for all samples received.

Here a few examples of what diseases may look like and how we processed them.