Monthly Archives: January 2015

Northern Channel Islands Algae Collection Trip

By Niko Kaplanis

In a recent collaboration with the Paul Jensen Lab here at Scripps, I travelled to the Northern Channel Islands to assist with collections for their research. The Jensen lab focuses on microbial distributions and interactions with marine plants and invertebrates as well as sequence-based approaches to the discovery of natural products from marine microbes. Our objective for the trip was to collect and identify as many algae and invertebrates as possible. The microbial communities growing in association with these samples were then to be processed and their genes searched for sequences which encode for the production of novel compounds.

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Getting ready for a dive

My experience with local marine algal species — accrued from field work for my invasive algal project and through serving as a TA for Jen’s phycology lab– earned me the title of seaweed identification expert for the trip, and I was put in charge of collecting and identifying algae. The recent discovery of invasive Sargassum horneri on Santa Cruz Island in 2012 provided a second personal objective for the trip — to add our collection sites to the list of locations where invasive algae had been searched for in the islands. We were specifically looking for this invasive alga also because a recently collected sample of this species from Catalina turned up a genetic sequence which encoded for the production of polybrominated diphenyl ethers or PBDEs. These chemical compounds are typically anthropogenically produced for use in industrial flame retardants, but this discovery suggested that microbial communities potentially growing specifically with this species could be a natural source. These compounds are known to bioaccumulate in both humans and marine mammals and to cause adverse health effects, specifically reducing fertility and having hormone-disrupting effects on estrogen and thyroid hormones. As such, identifying natural sources of these compounds is an active and important area of research.

Our trip began in Santa Barbara Harbor where we loaded our gear onto the Conception, a dive boat operated by the dive charter company Truth Aquatics. Motoring overnight through the rough seas of the Santa Barbara Channel put us at San Miguel Island, the westernmost island in the chain. Through the course of the next four days we would travel east, diving the leeward side of every island in the chain, ending in Anacapa Island.

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The wise and ever pensive Dr. Paul Jensen

The diving in the Northern Channel Islands proved to be remarkable, with many marine reserves harboring healthy kelp forests home to a diverse array of invertebrate, fish, and algal species. We were also blessed with abnormally warm water and calm seas, producing a feeling that we were diving an area more akin to the tropics than the California coast. Collections went smoothly, and we were able to collect and identify roughly a dozen unique algae at each site. Interestingly, Sargassum horneri only occurred at Anacapa Island, an area where it had not been previously documented. Whether these samples will produce sequences for novel compounds is not yet known, though the processing of these samples will soon give us an answer. Contributing to this project was a blessing, and I feel very lucky to have been a part of it, and to have been able to nurture a collaboration within our diverse institution.

 

Coral Reef Ecosystems: Human Impacts, Pristine Reefs & Conservation Strategies

Jeffery B. Graham Perspectives on Ocean Science Lecture Series presents Dr. Jenner Smith

Check out Dr. Smith’s presentation here!  http://www.ucsd.tv/search-details.aspx?showID=28675

Understanding how humans impact marine ecosystems is crucial to developing successful conservation strategies that protect the health of our ocean.  Discover how Scripps marine ecologist Jennifer Smith and her team are conducting research relevant to solving human-induced problems in environments ranging from coral reefs to the waters off our shores.

The CAU Slaughterhouse Chronicles

By Adi Khen

 

As a first-time volunteer at the Smith lab, I got to be involved in one of the most exciting parts of data processing: drying, weighing, acidifying and, basically, slaughtering CAUs!

Let me explain… CAU stands for Calcification Accretion Unit, or in this case a set of two stacked PVC tiles that are used to measure carbonate accretion and successional development on coral reefs. Three years ago, PhD student Levi Lewis installed 160 CAUs across 8 different reef sites on leeward Maui. Half of the CAUs at each site were “caged,” or enclosed in a stainless steel frame to prevent herbivory, while the rest were “uncaged.” Environmental characteristics at each site, such as temperature, light, pH, salinity, and sedimentation were also measured. By installing and later removing CAUs, researchers are able to sample reef communities without causing extensive damage to the reef.

This past summer, Levi removed all of his CAUs from the reef and brought them back to the lab. The macroalgae that had grown on the tiles, as well as the sediments that had collected on the tiles and the cryptic invertebrates that found shelter among them, were put into separate bags and frozen for future processing. All tiles were photographed for image analysis and then, our slaughterhouse was open for business.

Innocent CAUs laying out, completely unaware of what’s about to hit them

Innocent CAUs laying out, completely unaware of what’s about to hit them

After pouring 5% HCl on the CAUs, their carbonate instantly started dissolving

After pouring 5% HCl on the CAUs, their carbonate instantly started dissolving

About a day later, bare CAUs sitting on top of a container of their own fleshy (macroalgae and acid)

About a day later, bare CAUs sitting on top of a container of their own flesh (…y macroalgae and acid)

 

 

 

 

 

 

 

 

 

We dried the tiles in a drying oven, weighed them, let them soak in acid until all of their calcified matter dissolved, scraped them, and then dried and weighed them again (the difference between the initial and final tile masses would then represent the amount of carbonate accretion). We also filtered out the remaining fleshy matter from each tile, dried it, and weighed it to find the amount of fleshy biomass on each tile. After several months of the lab reeking of acid, we were left with about 300 clean PVC tiles, and we moved onto our next subjects: the macroalgae and invertebrates.

 

Macroalgae samples were also collected from the tiles in Maui, and were frozen for later analysis. Well, we thawed them, sorted each CAU’s algae by type or species, dried them, and then weighed them individually. We could then compare not only the difference in macroalgal cover between sites, but also the density and diversity of the macroalgal communities.

 

Microscope view of filaments of Dasya algae that had grown on one of the CAUs

Microscope view of filaments of Dasya algae that had grown on one of the CAUs

Microscope view of the growing tip of another thin branching alga

Microscope view of the growing tip of another thin branching alga

Microscope view of a cystocarp on Halichrysis, a leafy red alga

Microscope view of a cystocarp on Halichrysis, a leafy red alga

 

 

 

 

 

 

 

 

 

As for the frozen invertebrates, we thawed them, too, sieved them into different size categories, and then identified and quantified the critters from each CAU. This would help us determine the diversity, abundance, and potential importance of cryptic invertebrates in benthic communities.

 

Microscope view of a stomatopod found on one of the CAUs

Inverted microscope view of the same invertebrate (which I like to call, “inverted invert”)

My sketch of the “inverted invert,” now hanging by the lab’s microscope

My sketch of the “inverted invert,” now hanging by the lab’s microscope

 

 

 

 

 

 

 

 

 

 

These days, though our slaughterhouse is no longer in session, we’re getting ready to photoanalyze the surfaces of each of the CAUs to get a better picture of benthic community development on Maui’s reefs.

 

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