Nubble Dry Ledges 3/27/11

[oldflounder]

On New Years's Day I was at Nubble and slipped on this weird purple algae that was all over the low-mid tide ledges. There was a lot of the usual[not as slippery]green algae also. I was there again at the end of that month and again it was terribly slippery. So I have been avoiding going there below high-tide. I took a drive by yesterday for a look-see because I was in the area. It was 2 hours into the incoming tide and I was surprised to see that there are many patches of dry, algae free ledges at the entry/exit area all the way down to the lower water.

So for those of you that have been avoiding going there at low tide like I have been, it looks like for the next month or 2 the entry/exit should be a lot less exciting until the algae grows back.

 

[ScubaSarus]

You may be referring to the cyano bacteria type of growth on the rocks. Very slippery when wet.

I was at Narragansett Beach bodybording one evening and a fisherman at Hazard Ave 1/2 mile away was standing on the dry stuff. As soon as a swell came by, it wet the growth and he slipped over the ledge and they found him the next day pushed under the ledge in some nook.

That stuff is dangerous to all that wade the shore and I always point that out to someone if I can.

 

[oldflounder]

This is only my 3rd winter haunting the area. This January was the first time I had noticed this purple stuff. Maybe it is something that comes and goes like the gypsy moth catapiller. I hope so because it is slipperyer than wet ice. I'll have to Google it and do some research. Maybe the UNH Marine Studies people know something about it. They go there a lot.

 

[oldflounder]

That was an interesting Google search.

Cyano bacteria under certain conditions can reproduce explosively and cause algae blooms. Some of them produce cyano-toxins that can be harmful to surrounding species.

That might explain why the other green and brown algae seems to be gone this month and the rocks are so bare!!!

 

[ScubaSarus]

That's a good point. I never thought that it also out competed other algae but it makes sense.

 

[sunapeebob]

another bit of useless info - the cyanobacteria are being studied in Florida. These compounds that repel other algae seem to have some chemotherapeutic properties in cell culture. Something my son has expressed interest in. Slippery, but perhaps useful.

Bob