The day started with gusty winds and word of a swell. However, as this was the first plot retrieval day, we were determined to prepare to enter the water. There was a barge scheduled to arrive at 9am, so we went with Sara to Two Harbors to buy plastic bags for the afternoon collection. Since there wasn't much time for scuba, we moved on to the physiology trials. We prepared the agar for the next trial, weighed, and started the trial, and collected the agar from the previous trial.We also took pictures of the old agar on grid plates as backup data to analyze consumption should weight not be a reliable data source. We think that the water weight might be a factor.
Despite strong winds and swell and poor visibility, we trundled into the cove via the boat ramp. We felt like daring adventurers as we swam to mooring 11, dropped down, and collected algae from plots 1, 5, 8, 10, 11, 12, 13. With the surge and awful visibility it was difficult to cut the zip ties properly, but we think that scissors might be easier than knives to cut. On the journey back, Sara, Valerie, and Kaylee were separated from Eric. Once we reached the boat ramp, we loaded the algae bags into buckets and the cooler and took them back to the lab. We sorted through the Dictyota samples from about 7:30-10:30pm, all the while finding interesting species. Our sorting method involves pouring the seawater from the bag through window screening mesh, then rinsing the algae in freshwater for 30 seconds and then pouring the freshwater into the screen. The invertebrates are picked out of the window screen with forceps and counted in several categories as fit for the sample. Amphipods, shrimps, caprellids, and gastropod snails are the most common invertebrates. To subsample the plankton that made it through the screen, we pipet 3ml of the filtered water and then drop 10 drops into a plankton wheel and observe under a dissecting scope (level 12).
11/10 still crazy (even worse, in fact) winds.....counting inverts day and agar as per usual Today, we were not able to go diving due to very heavy winds and rough surface conditions. We stayed in the lab and continued our counts of invertebrates on the Dictyota plants from our plots. The previous day, we talked about doing plankton counts for each plot as a whole rather than for each plant to save time, but today we decided to do counts for each plant and not skip any more. Julia consulted an invertebrates book and found that the "Dictyota crabs" were a species called Pyromaia tuberculata.
Many of the plants we examined today were from the sand plots in Big Fisherman's Cove. These plots seem to be very rich in amphipods, but did not have very many shrimp compared to kelp plots. It may become apparent that the sand plots have much lower invertebrate diversity. Most plots also had large numbers of caprellids as well. Plankton counts were especially rich in ostracods, copepods, and amphipods. We also found very tiny juvenile snails, clams, diatoms, and Nemertean and polychaete worms.
Sara brought up an interesting question - where are all the plankton coming from? Do they haphazardly settle out of the water column, or do they choose to aggregate on the plants? We will probably discuss this in our paper.
11/11 LH retrieval, Sara came too.... horn shark/stingray, agar again, more inverts
Today, we went to Lion's Head in the morning to collect our first set of plots: 15, 19, 20, 23, 24, 25, and 28. The visibility was improving from the last few days, but was still not optimum. Before putting the plants into bags, we did a final set of fish surveys for all plants. As usual, we had to move the kelp off plot #18. Plot #25 (on the sand) had two large Lithopoma snails. One of the snails was on the Vexar, and one of them was on a Dictyota plant. A small horn shark swam through that same plot as well. We have never seen any horn sharks on our plots before. We also saw a stingray near our plots, which is unusual for Lion's Head.
Back in the lab, our first order of business was to get the agar trials set up. We created a bladed agar plate, a spiky agar plate, and a control agar plate.
After the agar trials were set up, we started counting all the invertebrates from our collected Dictyota plants. Lion's Head seems to have fewer shrimp and more amphipods than Big Fisherman's Cove. There are also fewer ostracods in the plankton samples from Lion's Head and possibly more worms from the phyla Nemertea and Platyhelminthes. It is interesting how plankton and invertebrate communities can vary on such a small scale. We also found several Navanax and Hermissenda slugs in our samples. Some very small juvenile sea slugs were seen in plankton samples. We are not sure whether or not we should include diatoms in the plankton data, since they are difficult to count accurately.
11/12 Monday- BFC dive, invert collection, watching tv, stats review Today was day 3 of plot collection and that meant that our diving in Big Fisherman's Cove was soon to be over. The final 7 plots: 2, 3, 4, 6, 7, 9, 14 were collected, bagged, and transported to the lab for invertebrate counting. Conditions were better today, as the swell had been calming down. There was nothing too unusual about the dive today, and collections were going more smoothly as we had gotten more experience cutting the zipties and bagging as quickly and effectively as possible.
After lunch, we began our lengthy lab reservation for 3 (5 if you count Shred-Ex). We began by completing another agar trial, weighed and took photographs of consumption, and implemented another trial. Not much consumption occured in the previous day's trial. We've gotten much better at grinding the algae, and have gotten a good procedure of agar plating down. Aside from this last trial, consumption has been very evident.
 |
| Valerie counting inverts on the window screen. After a 30 second freshwater rinse, the water and inverts were poured over the screen and quantified. |
After agar plating, we were able to start with the invertebrate counting. Luckily we had our buddies ShredEx there to join us in some Workaholics on a Monday afternoon. We've found that having TV shows playing has kept us entertained and able to push through 28 plants per day. We've all gotten much more efficient at counting, and have found some very interesting invertebrates, including a tiny white sea urchin! We spent the whole afternoon in the lab and left about 8-9 plants to be completed after dinner. We also had a statistics review meeting after dinner which pushed back the time we were in the lab. After the meeting we finished up our invertebrate counts, as we had just finalized plans to go diving at ShipRock with two of the Our World Underwater Scholar winners. The next day certainly was an experience of a lifetime.
-Eric and Kaylee
No comments:
Post a Comment