Phytoplankton: Wanted Dead or Alive

John D Hirsch MD

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Phytoplankton has a unique place in the evolution of life and remains the principal source of essential fatty acids including DHA and EPA and essential amino acids. DHA, in particular, represents between 40% and 60% of the structural lipids for brain, nerves, retina, and sperm in all animals. At the recent MACNA in Washington DC, we had a chance to visit the Smithsonian and view the exhibit on the evolution of humans. In that exhibit, they theorize that the availability of fish with high DHA levels was critical to the development and enlargement of the human brain which has a ratio of brain size to body size that is much greater than most animals. Essential amino acids cannot be synthesized by any animals and represent a significant portion of all functional and structural proteins. Without phytoplankton life likely would be very different.

Phytoplankton can be motile or non-motile, many are shades or green or golden brown. They each have different levels of Omega 3 fatty acids. Nannochloropsis is the most common species available in the trade, but it has lower levels of DHA than many others. Isochrysis, a golden brown species has one of the highest levels of DHA. Phytoplankton is the base of the food chain and must be an integral part of the nutrients required for a successful reef ecosystem. So who consumes it in your tank? Clearly zooplankton require it and research suggests that many sessile animals including corals do utilize phytoplankton as part of their diet. From there, gut loaded animals are consumed by the next level up the food chain passing those nutrients towards apex predators and human consumption.

So the big question, which is better? Dead or Alive. Dead phytoplankton, as long as it does not have the sulfur smell of decomposition has the same nutrient value as live. Dead phytoplankton is food and detritus, if not consumed. Live phytoplankton is food and while alive consumes nitrates, phosphates, and carbon dioxide producing oxygen. Before you buy phytoplankton, take the top off and take a smell. Your nose will guide your decision. If you are buying live, look for a born on date as I would be suspicious that live product could survive more than 30 days in a sealed container. I hope you are using one or the other. I am a fan of live, what about you?

Doc
 

John D Hirsch MD

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thanks 0h207 for the comment. I think the issue is related to dosing of any nutrient including phytoplankton. Over feeding or tank obesity causes fluctuations in pH, phosphates, nitrates, and oxygen levels. It is my opinion that the margin or error is less for live phytoplankton than dead phytoplankton. Saying that, I struggle to understand how much to dose either type. Do you dose daily or less often? Tank volume cannot be the only parameter for dosing. Flow, type and number of inhabitants and type of filtration/sump all play a role. How do you know when you over dosed or under dosed? How long does live phytoplankton survive once added to your tank?
More questions than answers. Any comments?
Doc
 

oh207

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thanks 0h207 for the comment. I think the issue is related to dosing of any nutrient including phytoplankton. Over feeding or tank obesity causes fluctuations in pH, phosphates, nitrates, and oxygen levels. It is my opinion that the margin or error is less for live phytoplankton than dead phytoplankton. Saying that, I struggle to understand how much to dose either type. Do you dose daily or less often? Tank volume cannot be the only parameter for dosing. Flow, type and number of inhabitants and type of filtration/sump all play a role. How do you know when you over dosed or under dosed? How long does live phytoplankton survive once added to your tank?
More questions than answers. Any comments?
Doc
I dose manually once a week. I dose 20ml into a 65g tank. I've used the Kent PhytoPlex and Chomaplex. I get the 64oz containers and they last a while. I can't say that I've given any deep thought as to why I used the products. Or cared for whether they are dead or alive. I read the reviews and the advertising literature, and then decided that it sounds good and that I want to use it.

I usually dose at night and I turn off the skimmer for 6 hours (until next morning). When I first started using the product I used to dose multiple times a week. Now I just do it on Sundays after I clean the skimmer.
I have no idea whether I can underdose or overdose this product. A year ago I picked up an 8oz bottle of "green water" (live phyto) from a local hobbyist who was culturing the stuff. I emptied the entire bottle into the tank, nothing happened. Or I should say, nothing noticeable to me.
 

C-Dragon

Chad Clayton
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Feeding too much of anything can cause detritus, including live algae. If you put 1 billion cells of algae, dead or alive, in a tank, you run the risk of polluting the tank. Just because the algae is alive doesn't mean that it will all get consumed. Also, non-viable marine phytoplankton, when put into a tank, does not immediately begin to degrade (I have heard this claim by a number of people). Algal cells have very durable cell walls and membranes that don't simply break down quickly. I see this in my copepod cultures when I feed them non-viable algae. These cells are also highly resistant to bacterial invasion. I recommend everyone read the labels on products with the recommended dosage information. Start off conservative and go from there.

I agree with Dr. Hirsch that live algae sold into the market place can have a very short life-span. There are a few reasons why this is the case. One is that live algae require nutrients and light to grow. If you deprive them of both, they begin the process of senescence (loss of cell's power to divide and grow) which, depending on the species, can take days or longer before the cell begins to go through autolysis (self-digestion). These processes can be slowed with refrigeration, but refrigeration can be hard on certain species of algae, specifically the brown alga Isochrysis and Pavlova. Without refrigeration, the process is surely accelerated. Also, as soon as live algae are put into a container, they continue to consume the nutrients surrounding them. They go through cellular fission just like they would in the culture. When the nutrient begins to deplete, the cells begin to change their biochemistry, which alters the nutritional content. For example, if you stop feeding nutrient to a Nannochloropsis culture while still giving them plenty of light, the algae, and it's photosynthesis apparatus, begin to change; they start to produce carotenoids and the lack of nitrogen inhibits other biological processes. Here is a good paper on the subject: The Response of Nannochloropsis gaditana to Nitrogen Starvation Includes De Novo Biosynthesis of Triacylglycerols, a Decrease of Chloroplast Galactolipids, and Reorganization of the Photosynthetic Apparatus. Eukaryot Cell 2013 May;12(5):665-76. doi: 10.1128/EC.00363-12. Epub 2013 Mar 1. The non-viable (dead) algae retain their nutritional value for months and are harvested at peak growth. Dead algae also runs the risk of spoilage if it is not handled properly. It is certainly important to consider these details when making a purchase.

Chad
 
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John D Hirsch MD

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I am sorry for the delayed response but I have just returned from an adventure observing cetaceans in the Sea of Cortez. First, I want to thank Chad for his informative and educational response. I hope you are a regular contributor to this forum as you add another dimension to those of us who believe that a varied all natural diet is both necessary and sufficient to a success experience.
For those of you who now understand the need for adding phytoplankton, you have choices and information to make those choices. You can't make a bad choice.
For those who are interested in growing your own, it is easy to grow, just hard to maintain.
Doc
 

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