We just finished a 'short' (5 week) field season for culturing planktic foraminifera at the Wrigley Marine Science Center on Catalina Island. This is our 4th field season in 5 years and the last field season on our current culture grant. We LOVE coming here. We can capture live forams less than 10 minutes from the lab in deep water and have them in culture within hours of collection.
This summer, mother nature did not cooperate with our research plans. Instead of getting the usual species we have seen here over the last few years, mother nature threw us a curve ball and El Nino is to blame....The water mass off the coast of Catalina averaged 22.5°C over the course of our field season (nearly 24°C on some days) and was very oligotrophic. Probably sub-tropical in origin... Not the water mass we need if we want the nutrient loving N. dutertrei (or at least we think it is nutrient loving). We needed to collect O. universa and N. dutertrei. G. bulloides would have been ideal too for our collaborators. We did manage to culture enough O. universa and N. dutertrei to complete most of our experiments, but we really needed numbers to be higher. G. bulloides was nearly absent.
So what did we get? Forams that are not common here: G. humulis (I didn't even know of this foraminifer until this summer - I've never seen it in fossil samples I've picked through), G. calida, T. rubescens, G. siphonifera, a few Globorotalids and a handful of others... It wasn't ideal, but we made the best of it by getting some specimens we caught in the nets to recover or taking dive caught specimens and growing them in seawater labeled with an isotope so we could track calcification. And of course, we took pictures and documented what we learned. Here are a few of my favorites...
This is one tiny foram. This one measured <150 microns on the longest dimension. It had very light brown cytoplasm (darker on the inverted scope). The first day it was caught it did not have symbionts out and the spines were nearly absent and the last two chambers were very thinly calcified and were not full of cytoplasm. These pictures were taken after day 5 in the lab. I did feed it a frozen (thawed) Artemia nauplii on day 2 or 3.
This was a dive caught specimen. On day 2 or 3 in culture, it formed a new chamber, so we transferred it into seawater that contained an isotope label so that we can identify the calcite that grew in culture. It took us a LONG time to identify what species it was, because it was SO very weird looking in culture. The first two pictures were taken on day 2 or 3 and the last picture was taken on day 5 in culture. After the new chamber filled in, the specimen died or went through gametogenesis.
I really don't know if the name above is correct: is it a Globoturborotalita rubescens or Globigerina rubescens. Either way, I'm certain we have never seen this in the plankton tows here on Catalina Island. They are SO distinctly different from all of the other forams because they are quite small and their shells are VERY pink in color. Almost like the pink G. ruber. They were very very abundant in our tows - probably the most abundant of all of the forams. The divers never caught one of these, probably because they are so small. Or they don't live at the surface where the divers spend heir time (<5m depth). We tried to get these to recover and grow in seawater with an isotope label, but very few recovered. Only two recovered well enough to be photographed.
G. menardii has been in culture before by other researchers, but we don't often capture them near Catalina Island. This one has been in culture since it was caught on August 13 and it is still kicking. On occasion, it looked very deformed as it grew and added chambers, but then would look like it calcified without any deformation, so I'm not really sure how to interpret what we've observed on a day to day basis.
Globorotalia crassaformis (?)
This deep dweller didn't live very long and is archived so we can take pictures on the SEM. We think it is a G. crassiformis.
G. crassaformis or truncatulinoides
Initially identified as a G. truncatulinoides... The jury is still out on this one. Our field season overlapped with a workshop on the biology of planktic foraminifera and several researchers observed this specimen. Two thought it was a G. crassiformis and two thought it was a G. truncatulinoides. I think post-culture SEMs will be needed. It was captured on 8/26 and is still alive. It was transferred in and out of labeled seawater on a day/night schedule to label calcification on a 24 hour time period for 9 days. Then on 9/5 it was transferred into a different label where it will stay until it undergoes gametogenesis or dies. The first two pictures were taken the day after this specimen was collected. The next two pictures were taken 7 days after collection (one after it was fed an artemia). Notice the small brown specks around the foram in the first two pictures? I have no idea what those are but they look REALLY similar to the symbionts found around N. dutertrei. According to Gastrich, 1987, G. truncatulinoides doesn't contain symbionts. I'm not sure anyone has investigated the presence/absence of symbionts in G. crassiformis. In any case, we aren't sure what these specks are. We do know that N. dutertrei expels its symbionts a few days before gametogenesis, so perhaps some of the other deep dwellers have symbionts and the ones investigated thus far were pregametogenic adults without symbionts? Just a thought.