Sun on my face and wind in my hair, scanning the expanse of blue. Forty minutes on, twenty minutes off, from sunrise until sunset, day after day. Hours of seemingly empty blue, punctuated by graceful black-footed albatrosses wheeling and gliding over the swells, by the splashing approach of a curious group of Pacific white-sided dolphins coming to play in the bow of the ship, by whale spouts on the horizon and the occasional breaching humpback. A flurry of data entry- geographic coordinates, bearing and distance from the ship, number of animals, species identification, behavior- and then back to blue.
I've just returned from the Northern California Current (NCC) ecosystem cruise aboard NOAA ship Bell M. Shimada. My role on board was the marine mammal observer, logging marine mammal sightings during the transits between sampling stations. We surveyed and sampled between Cape Mears, Oregon and Trinidad, California, from right along the coast out to 200 nautical miles offshore. Resources in the marine environment are patchy, and our coastline is highly productive.This diversity in environmental conditions creates niche habitats for many species, which is one reason why surveying and sampling across a broad geographic range can be so informative.
We left Newport surrounded by gray whales, feeding in green, chilly waters at temperatures around 12°C. Moving west, the marine mammal and seabird sightings were increasingly sparse, the water increasingly blue, and the surface temperature warmed to a balmy 17°C. We had reached offshore waters, an ocean region sometimes referred to as the 'blue desert'. For an entire day I didn't see a single marine mammal and only just a few seabirds, until a handful of common dolphins- more frequently seen in warm-temperate and tropical waters to the south- joined the ship at sunset. As we transited back inshore over the productive Heceta Bank, the water became cooler and greener. I stayed busy logging sightings of humpback and gray whales, harbor porpoise and Dall's porpoise, pacific white-sided dolphins and sea lions. These far-ranging marine predators must find a way to make a living in the patchy and dynamic ocean environment, and therefore their distribution is also patchy- aggregated around areas of high productivity and prey availability, and occasionally seen transiting in between.
Here are a few cruise highlights:
Curious groups of common dolphins (Delphinus delphis) came to play in the bow wake of the ship and even checked out the plankton nets when they were deployed. Common dolphins are typically found further south, however we saw several groups of them in the warmer waters far offshore.
Ocean sunfish (Mola mola) will occasionally lay themselves flat at the surface so that seabirds will pick them clean of any parasites. I was delighted to observe this for the first time just off Newport! There were several more sunfish sightings throughout the cruise.
A masked booby (Sula dactylatra) hung around the ship for a bit, 16 nautical miles from shore, just south of the Oregon-California border. Considered a tropical species, a sighting this far north is extremely rare. While masked boobies are typically distributed in the Caribbean and tropical Pacific from Mexico to Australia, one found its way to the Columbia River in 2006 (first record in the state of Oregon) and another showed up here to Newport in 2015- reportedly only the second to be recorded north of Mendocino County, California. Perhaps this sighting is the third?
While most of my boat-based fieldwork experiences have been focused on marine mammal research, this was an interdisciplinary cruise aimed at studying multiple aspects of the northern California current ecosystem. There were researchers on board studying oceanography, phytoplankton and harmful algal blooms, zooplankton, and microplastics. When a group of enthusiastic scientists with different areas of expertise come together and spend long days at sea, there is a wonderful opportunity to learn from one another. The hydroacoustic backscatter on the scientific echosounder prompted a group discussion about vertical migration of plankton one evening. Another evening I learned about differences in energetic content between krill species, and together we mused about what that might mean for marine predators. This is how collaborations are born, and I am grateful for the scientific musings with so many insightful people.
Thank you to the Shimada crew and the NCC science team for a wonderful cruise!
Slimy, pink, and rather inanimate, despite their unusual appearance pyrosomes have been the subject of much discussion in the last couple years. But, what are these things (really) and why should we care that they're here? In short, pyrosomes are warm-water, colonial tunicates that have expanded northward along the northern California Current (NCC). In 2017, pyrosome abundances were so high that fishing nets and research nets alike were ripped open because of the sheer amount of pyrosomes being caught (yikes!). Studies done on pyrosomes (and other tunicates) have indicated that during blooming events similar to what we've experienced off the coast of Oregon, significant proportions of the phytoplankton standing stock may be removed due to their high grazing rates; bad news for other zooplankton grazers including key species like euphausiids and copepods.
This summer, as a part of my REU internship, I was able to aid in an ongoing NSF funded project headed by Kim Bernard at Oregon State University looking at the impact pyrosomes have on the phytoplankton standing stock in the NCC. With data and specimens collected by NOAA fisheries surveys on the R/V Bell M. Shimada in March and May of 2018 and gut evacuation experiments conducted aboard the R/V Sally Ride in June 2018, I was able to calculate what impact grazing pyrosomes could have on phytoplankton standing stock. In the end, my results indicated that while pyrosomes occurred in high abundances and showed a doubling in average size from March to May (70 mm to 140 mm, respectively), they seem to have had a rather small grazing impact on the phytoplankton standing stock. However, when pyrosome abundances are extremely high like they were last year, their impact may still be considerable.
I was lucky enough to be able to work aboard the R/V Bell M. Shimada during its recent September NOAA fisheries survey, dip-netting pyrosomes for more experiments. Shockingly, all of the pyrosomes collected in September were tiny with the longest ones not even surpassing 50 mm! We never encountered pyrosomes near the surface and our plankton nets collected 7 total individuals. This finding prompts many more questions regarding these mysterious creatures and why the large ones seem to have disappeared, leaving miniatures in their place. Is it a part of their lifecycle or are there other forces at play? What does this mean for pyrosomes abundances in 2019? In the midst of all these questions one thing is certain: there is much more to learn here and going forward we are excited to see what the future holds.
We deployed our bongo nets at the end of the Heceta Head line, as our second successful day of an 9-day research cruise aboard the NOAA ship Bell M. Shimada came to a close. Once retrieved, the bongos were full of what can best be described as goo. Impeding zooplankton and krill sorting as well as slowing water filtering, the goo warranted a closer inspection. Using a compound microscope, we were surprised by intricate silica spherical basket structures. Within the silica lattices were forams as well as a variety of phytoplankton. Observers immediately classified the structures as radiolarians, but our curious crew wasn't ready to give up the case.
After much conjecture and a few well-suited search engine key words selected by OSU's Maria Kavanaugh, we arrived at phaeodaria. Phaeodarians tend to live below 300 m in pelagic environments, however in the California Current Ecosystem, they are typically found between 100 and 150 m. Recent studies have shown that they play an important role in both deep-sea silica transport and carbon cycling. Apparently, phaeodarian biogeography is not well known, and the foundation of our knowledge remains as Ernst Haeckel's 1887 monographs of radiolarians collected from the Challenger Expedition. Recent genetic advancements have shown that phaeodarians should be grouped within Cercozoa rather than Radiozoa. Contributing to their mystery is the fact that phaeodarian structures are delicate, making it difficult to capture them in plankton tows or be preserved in sediments.
Phaeodarians range from 40 um to 2 mm in size and may display well-developed and ordered matrixes or be presented as scattered spicules with an organic internal structure. We were lucky enough to encounter examples of both types. Not only do we now have an explanation for our goo, we also all learned a little more about our own California Current Ecosystem. As phaeodarian research advances, we hope to learn more and possibly enjoy the company and expertise of a Rhizaria expert while conducting future surveys.
Biard T, Krause JW, Stukel MR, Ohman MD. 2018. The Significance of giant Phaeodarians (Rhizaria) to Biogenic Silica Export in the California Current Ecosystem. Global Biogeochemical Cycles.
Cheslow D. 2018. Lava From Kilauea Boils Away Freshwater Lake In Hawaii. NPR.org. [accessed 2018 Aug 17]. https://www.npr.org/2018/06/07/617860832/lava-from-kilauea-boils-away-freshwater-lake-in-hawaii.
Stukel MR, Biard T, Krause J, Ohman MD. 2018. Large Phaeodaria in the twilight zone: Their role in the carbon cycle. Limnology and Oceanography.
We have just returned from another successful Northern California Current (NCC) ecosystem research cruise aboard the NOAA ship Bell M. Shimada. We sampled seven transects from Cape Meares in central Oregon to Trinidad Head off northern California. We had a great team of scientists aboard involved in a variety of projects studying hydrography, zooplankton species composition and abundance, zooplankton genomics, harmful algal blooms, phytoplankton pigments, microplastics, pyrosomes, and marine mammals.
Some notable observations include hypoxic (oxygen concentrations <1.4 ml/L) conditions on the shelf along the Newport and Cape Meares transects and relatively warm (17°C) offshore surface temperatures along Newport Oregon and Crescent City California. In terms of biology, our nets were full of Phaeodaria offshore, we encountered large euphausiids off Crescent City, and a conspicuous lack of pyrosomes along the coast. Stay tuned for more information as we begin to collate all of the data we collected during this productive and successful 9 day research cruise aboard the Bell M. Shimada.