Red Algae

A group of European researchers have studied a seaweed named Gracilaria gracilis that grows in the tidepools around Europe.  This seaweed is in a class of red algae known as Florideophyceae, and has separate male and female forms.  Unlike many marine organisms the females do not release their eggs into the water to be fertilised, but retain them in funnel shaped filaments.  The male seaweeds release sperm into the water, but the sperm do not have tails to propel them through the water and must rely on water currents to move them.  This is an apparently inefficient setup for reproduction, as it makes it hard for the non-swimming sperm to meet up with the eggs inside filaments. 

Researchers in France noted that small isopods, tiny crustaceans named Idotea balthica, crawled around on the seaweeds.  The researchers examined the isopods and found seaweed sperm on the body surface of the isopods.  The sperm have a sticky coating that attaches them to the isopods.  The research team set up an experiment that showed isopods were transporting sperm from males to females, just like pollinators of land plants. 

Also like plants and pollinators, the relationship between seaweed and isopods seems to be mutually beneficial.  The isopods feed off diatoms – single celled algae that grow on the surface of the seaweed.  This keeps the red seaweed clean and therefore facilitates photosynthesis and enables the seaweed to grow faster.  Living amongst the red seaweed may help the isopods avoid predators as the juvenile isopods are a similar colour to the seaweed. 

In a review article about the research Jeff Ollerton and Zong-Xin Ren commented: “Interactions between different species are the engine that makes ecosystems function effectively.” 

They and the researchers who carried out the experiments also speculated about when the mutualism between seaweed and isopods began, as the seaweed is believed to have evolved around 1,000 million years ago, but the isopods not until around 650 million years ago. Jeff Ollerton and Zong-Xin Ren suggest “It is possible that before this, red seaweeds relied on some other now-extinct marine invertebrates as pollinators”.

References: Science (AAAS) News, 28 July 2022; Science 28 July 2022 doi: 10.1126/science.abo6661; Science Perspectives 29 July 2022 doi: 10.1126/science.add3198.

Editorial Comment
:  We can easily solve the problem of the 350 million year gap between the origin of seaweed and the origin of isopod – it doesn’t exist.  Therefore, we don’t need to invent an imaginary pollinator for which there is no evidence. 

The interaction of isopods and red seaweed has all the hallmarks of a designed system that doesn’t work until all the components are in their place and functioning.  As the comment by Ollerton and Ren correctly points out, nothing in the living world works in isolation, and the more we study it the more interactions between different species we find. 

This is exactly what you would expect according to Genesis, which tells us that God made a world filled with whole functioning ecosystems in six days.  Red seaweeds were made on the third creation day, along with all the other plants, ready to reproduce after its kind.  They didn’t have to wait long for pollinators ready to collect their reproductive cells.  Isopods were made on the fifth creation day, when they found a ready supply of food in the form of diatoms on red seaweed, and were able to start ferrying red seaweed reproductive cells, which were well designed to attach to their carriers, to their proper place.

Photo of Gracilaria sp. : Rickard Zerpe CC BY 2.0

Creation Research News 3 August 2022

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