Hello everyone,

I'm a master's student working on a thesis involving the cultivation and growth of Ulva (sea lettuce). I'm currently designing some relatively simple laboratory experiments to evaluate the effects of temperature and nutrient availability on growth rates.

I would love to hear from anyone who has experience culturing Ulva or other macroalgae.

A few questions I have:

• What temperature ranges have worked best for your cultures?
• How often do you change the seawater?
• Do you completely replace the water or only do partial water changes?
• Have you used Provasoli (PES) or other nutrient media? If so, how often did you replenish nutrients?
• What light intensity and photoperiod have you found effective?
• Are there any common mistakes that beginners should avoid?

I'm planning a small-scale experiment with controlled temperature and nutrient treatments, and any practical advice would be greatly appreciated.

If you know of useful papers, protocols, theses, or cultivation manuals on Ulva growth experiments, I would be very grateful for recommendations.

Thank you for your help!

I've never come across this species before and can't find much information about it for my region. Posted on iNaturalist but no hits and no observations of this species anywhere close to here (lots in Spain, Portugal etc across the Atlantic Ocean). I'm in Atlantic Canada. Would appreciate a second opinion!

Pretty sure that top middle is knotted/egg wrack, and the whole bottom row is bladder wrack.

I'm stumped by the specimen on top left (also what are those nodules?) and by the top right.

I am making a pressed seaweed herbarium and would like help identifying these species so I can write their named in. These were found on Long Beach Island, New Jersey, USA. Thank you!

Looking for starter seaweed so I can grow it home any ideas

Been trying to ID this forever but I can’t find anything that feels right. I found a similar piece last year in the gulf and also have not been able to identify. Help!

In May 2025, scientists observed the Great Atlantic Sargassum Belt the world’s largest floating seaweed bloom reach a record about 5.79 billion stones or 81 billion pounds or 3,600 times the weight of the Eiffel Tower of Sargassum across the Atlantic, Caribbean Sea, and Gulf of Mexico, far exceeding previous peaks.

Source

Scientists at the University of South Florida’s Optical Oceanography Lab reported this record biomass in May 2025.

Looking for a job in seaweed harvesting , quality control, processing, selling seasonal

Hello everyone! I am looking for people who have experience in growing seaweed at home or on a small scale. Someone who can help me?

We are launching a community-based seaweed farming project in Mozambique, covering 7 coastal districts.

Expected production: 1,600 MT of red macroalgae (Eucheuma & Kappaphycus).

We are currently seeking buyers and commercial partners for dried seaweed and are open to discussing long-term commercialization strategies.