Kelp Lines covered in brown algae
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Hi All,
After not checking the lines over the holidays I've come back to kelp lines covered in some form of brown algae. Shaking and agitating the lines in the water appears to remove most of the algae. I'm concerned that the algae may be suffocating the kelp and will keep coming back. Does anyone have any experience or advice on how to combat this issue?
Note, the lines are located in Gowanus Bay, Brooklyn, NY. This site is downstream from multiple CSOs so it is very high in nitrogen and pollutants. The kelp is not intended for consumption.
Thanks in advance for any advice.
Justin
Hi @justin_realmuto , I am uncertain which species you mean by "kelp", but assuming it is Saccharina latissima, Alaria esculenta, Laminaria digitata or similar, it sounds like your site is positioned in an area that is not favourable for these species. They tend to favour less brackish waters whilst the kinds of problematic brown algae you've described do better in these higher nitrogen more brackish waters.
Is this the first year growing at this site? are there healthy kelp beds near or upstream from the site?
These problematic brown algae are still known to grow in waters that are most favourable to kelp species, so it is often growing on the lines of other sites I have worked on. I have seen kelp grow through some covering of these problematic brown algae, but from your description of how it is coming away from the lines it sounds like there is more on them than I have ever seen. I'd be interested to know if any kelp does come through later in the season.
If this is a bioremediation project you are working on, perhaps the "problematic" brown algae could be the pollutant sponge instead of the kelp.
@iskander_bond Thank you! Yes, we're growing saccharina latissima, it's the very first time it's been grown at this site, and there are no other sites nearby that I'm aware of. I do know that another group successfully grew kelp in Newtown Creek (another polluted waterway in Brooklyn). We're hoping we can make it work too. We'll be using what we grow for bio-fuel and as an additive to cement. Unfortunately, the nuisance algae seems to form a thin layer on everything we put in the water (ropes, docks) but not grow a sturdy structure like kelp does. Thank you for your advice and I'll reply with some posts down the road if we can get this to work.
@iskander_bond Thank you! Yes, we're growing saccharina latissima, it's the very first time it's been grown at this site, and there are no other sites nearby that I'm aware of. I do know that another group successfully grew kelp in Newtown Creek (another polluted waterway in Brooklyn). We're hoping we can make it work too. We'll be using what we grow for bio-fuel and as an additive to cement. Unfortunately, the nuisance algae seems to form a thin layer on everything we put in the water (ropes, docks) but not grow a sturdy structure like kelp does. Thank you for your advice and I'll reply with some posts down the road if we can get this to work.
@justin_realmuto Hi Justin! Does the slime you're seeing look similar to this? Sharing a post from a farmer in Rhode Island last year who also had trouble with slimy brown algae suffocating her lines, and had them scientifically ID'd as diatoms!
I've heard some farmers say that if you are able to outplant earlier in the season, sometimes the kelp can get enough growth in to outcompete the other species. @michael_doall contends with a fair amount of slip gut on Long Island, he might have some other suggestions.
@lindsay_olsen Thanks Lindsay. That very well might be the same things. The best way I describe it is that it looks like brown slime when you pull it out the water and brown hair when it's in the water. I think I'll definitely experiment with planting earlier next season but for now I'm trying the pull off whatever I can and then I might adjust the depth of the lines based on what attracts the least biofouling.
@lindsay_olsen Thanks Lindsay. That very well might be the same things. The best way I describe it is that it looks like brown slime when you pull it out the water and brown hair when it's in the water. I think I'll definitely experiment with planting earlier next season but for now I'm trying the pull off whatever I can and then I might adjust the depth of the lines based on what attracts the least biofouling.
@justin_realmuto Hi Justin, the 'brown slime' is a problem in several Long Island (NY) bays/estuaries where I have grown sugar kelp. I think in most cases the slime at my sites is a brown macroalgae of the genus Ectocarpus, but could also be 'tube dwelling diatoms' as Lindsay mentioned was identified on some farms by scientists Dr. Lucie Maranda and Hongjie Wang at URI. In either case, we call it 'slip-gut' and its a major nuisance that can impede kelp growth by smothering it in its early stages. Early in the growing season at my Long Island study sites its often a race between the slipgut and the sugar kelp for supremacy. I've done experiments seeding lines at different time points through December and January, and kelp typically seems better able to outcompete the slipgut when lines are seeded earlier (December). Slip-gut seems to be a lot more problematic to the kelp when lines are seeded later (late december-January). One thing I do to try to keep the lines clean is shake them in the water to remove the slipgut, but this is only effective when the slipgut is little right after settling. Once the slipgut grows its very hard to shake off, and its very time-consuming to remove it by hand. Sometimes I've had lines look like complete slip-gut, but was surprised to find kelp blades buried in the slip gut. Not only does the slipgut shade the kelp, but it is probably also competing for nutrients.
@michael_doall Thank you! Based on your description it sounds like I have slipgut. I also noticed that sometimes under all that brown slime there are still some kelp blades holding on. I'm going to remove as much as I can from portions of my kelp line and see how long it takes for it to come back.
@michael_doall Thank you! Based on your description it sounds like I have slipgut. I also noticed that sometimes under all that brown slime there are still some kelp blades holding on. I'm going to remove as much as I can from portions of my kelp line and see how long it takes for it to come back.