Tuesday 20 May 2014

Morphological description of Asparagopsis and Falkenbergia (the marine asparagus and its fluffy pom-pom)

Species and cryptic lineages of the red seaweed Asparagopsis are well-known for their use in biodiscovery, in aquaculture as biological filters but also as notorious invaders and pests causing decline in biodiversity worldwide. The species in this genus, A. armata and the cryptic species complex A. taxiformis, which embraces at least four genetic lineages, share nearly identical tetrasporophytes (i.e., the Falkenbergia stage). One of the A. taxiformis cryptic lineages, the so-called invasive lineage 2, is equipped with unique ecophysiological features. When conditions are met, in short amounts of time, lineage 2 takes over on other, less aggressive, non-native or even local endemics and leaves behind either “dense purple gametophyte forests” or “dense purple tetrasporophyte mats”.
 
 
However, not all of the A. taxiformis cryptic lineages are invasive. Very often, not all of the Asparagopsis gametophytes or tetrasporophytes from within the “purple forest” or the “purple mat” belong to the same lineage. Obviously the prompt identification of a pest is crucial in support of its sustainable management especially when the pest is hidden within morphologically identical conspecifics. In the case of Asparagopsis, only DNA sequencing could tell gametophytes and tetrasporophytes of the cryptic lineages apart. But not anymore! Marianela Zanolla (UMA) in her recently published paper was able to identify morphologically tetrasporophytes and gametophytes of Asparagopsis species and cryptic lineages collected from the Mediterranean Sea and the Hawaiian Islands. Basically these are the places where multiple Asparagopsis lineages are found within few hundred yards. But please pay attention! If you are a marine aquaria lover, you still need to purchase a microscope or a PCR for some DNA analyses. Read more here…