Alatalo
Philip
Alatalo
Philip
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ArticleLuciferin production and luciferase transcription in the bioluminescent copepod Metridia lucens(PeerJ, 2018-09-14) Tessler, Michael ; Gaffney, Jean P. ; Crawford, Jason M. ; Trautman, Eric ; Gujarati, Nehaben A. ; Alatalo, Philip ; Pieribone, Vincent A. ; Gruber, David F.Bioluminescent copepods are often the most abundant marine zooplankton and play critical roles in oceanic food webs. Metridia copepods exhibit particularly bright bioluminescence, and the molecular basis of their light production has just recently begun to be explored. Here we add to this body of work by transcriptomically profiling Metridia lucens, a common species found in temperate, northern, and southern latitudes. In this previously molecularly-uncharacterized species, we find the typical luciferase paralog gene set found in Metridia. More surprisingly, we recover noteworthy putative luciferase sequences that had not been described from Metridia species, indicating that bioluminescence produced by these copepods may be more complex than previously known. This includes another copepod luciferase, as well as one from a shrimp. Furthermore, feeding experiments using mass spectrometry and 13C labelled L-tyrosine and L-phenylalanine firmly establish that M. lucens produces its own coelenterazine luciferin rather than acquiring it through diet. This coelenterazine synthesis has only been directly confirmed in one other copepod species.
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ArticleA regional, early spring bloom of Phaeocystis pouchetii on the New England continental shelf(American Geophysical Union, 2021-01-15) Smith, Walker O. ; Zhang, Weifeng G. ; Hirzel, Andrew ; Stanley, Rachel M. ; Meyer, Meredith G. ; Sosik, Heidi M. ; Alatalo, Philip ; Oliver, Hilde ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Mehta, Arshia ; McGillicuddy, Dennis J.The genus Phaeocystis is distributed globally and has considerable ecological, biogeochemical, and societal impacts. Understanding its distribution, growth and ecological impacts has been limited by lack of extensive observations on appropriate scales. In 2018, we investigated the biological dynamics of the New England continental shelf and encountered a substantial bloom of Phaeocystis pouchetii. Based on satellite imagery during January through April, the bloom extended over broad expanses of the shelf; furthermore, our observations demonstrated that it reached high biomass levels, with maximum chlorophyll concentrations exceeding 16 µg L−1 and particulate organic carbon levels > 95 µmol L−1. Initially, the bloom was largely confined to waters with temperatures <6°C, which in turn were mostly restricted to shallow areas near the coast. As the bloom progressed, it appeared to sink into the bottom boundary layer; however, enough light and nutrients were available for growth. The bloom was highly productive (net community production integrated through the mixed layer from stations within the bloom averaged 1.16 g C m−2 d−1) and reduced nutrient concentrations considerably. Long‐term coastal observations suggest that Phaeocystis blooms occur sporadically in spring on Nantucket Shoals and presumably expand onto the continental shelf. Based on the distribution of Phaeocystis during our study, we suggest that it can have a significant impact on the overall productivity and ecology of the New England shelf during the winter/spring transition.
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ArticleDiatom hotspots driven by western boundary current instability(American Geophysical Union, 2021-05-11) Oliver, Hilde ; Zhang, Weifeng G. ; Smith, Walker O. ; Alatalo, Philip ; Chappell, Phoebe Dreux ; Hirzel, Andrew ; Selden, Corday ; Sosik, Heidi M. ; Stanley, Rachel H. R. ; Zhu, Yifan ; McGillicuddy, Dennis J.Climatic changes have decreased the stability of the Gulf Stream (GS), increasing the frequency at which its meanders interact with the Mid-Atlantic Bight (MAB) continental shelf and slope region. These intrusions are thought to suppress biological productivity by transporting low-nutrient water to the otherwise productive shelf edge region. Here we present evidence of widespread, anomalously intense subsurface diatom hotspots in the MAB slope sea that likely resulted from a GS intrusion in July 2019. The hotspots (at ∼50 m) were associated with water mass properties characteristic of GS water (∼100 m); it is probable that the hotspots resulted from the upwelling of GS water during its transport into the slope sea, likely by a GS meander directly intruding onto the continental slope east of where the hotspots were observed. Further work is required to unravel how increasingly frequent direct GS intrusions could influence MAB marine ecosystems.
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PreprintEffects of turbulence on the feeding rate of a pelagic predator : the planktonic hydroid Clytia gracilis( 2005-12-14) Adamik, Peter ; Gallager, Scott M. ; Horgan, Erich F. ; Madin, Laurence P. ; McGillis, Wade R. ; Govindarajan, Annette F. ; Alatalo, PhilipRelatively little is known about the role of turbulence in a predator - prey system where the predator is a passive, pelagic forager. The Campanulariid hydroid Clytia gracilis (Cnidaria, Hydrozoa) is unusual because it occurs as planktonic colonies and is reported to forage passively in the water column on Georges Bank, Massachusetts, USA. In this study we investigated the role of various turbulence conditions on the feeding rate of C. gracilis colonies in laboratory experiments. We found a positive relationship between turbulence velocities and feeding rates up to a turbulent energy dissipation rate of ca 1 cm2 s-3. Beyond this threshold feeding rate decreased slightly, indicating a dome-shaped relationship. Additionally, a negative relationship was found between feeding efficiency and hydroid colony size under lower turbulent velocities, but this trend was not significant under higher turbulence regimes.
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ArticleLingering Chukchi Sea sea ice and Chukchi Sea mean winds influence population age structure of euphausiids (krill) found in the bowhead whale feeding hotspot near Pt. Barrow, Alaska(Public Library of Science, 2021-07-12) Ashjian, Carin J. ; Okkonen, Stephen R. ; Campbell, Robert G. ; Alatalo, PhilipInterannual variability in euphausiid (krill) abundance and population structure and associations of those measures with environmental drivers were investigated in an 11-year study conducted in late August–early September 2005–2015 in offshelf waters (bottom depth > 40 m) in Barrow Canyon and the Beaufort Sea just downstream of Distributed Biological Observatory site 5 (DBO5) near Pt. Barrow, Alaska. Statistically-significant positive correlations were observed among krill population structure (proportion of juveniles and adults), the volume of Late Season Melt Water (LMW), and late-spring Chukchi Sea sea ice extent. High proportions of juvenile and adult krill were seen in years with larger volumes of LMW and greater spring sea ice extents (2006, 2009, 2012–2014) while the converse, high proportions of furcilia, were seen in years with smaller volumes of LMW and lower spring sea ice extent (2005, 2007, 2010, 2011, 2015). These different life stage, sea ice and water mass regimes represent integrated advective responses to mean fall and/or spring Chukchi Sea winds, driven by prevailing atmospheric pressure distributions in the two sets of years. In years with high proportions of juveniles and adults, late-spring and preceding-fall winds were weak and variable while in years with high proportions of furcilia, late-spring and preceding-fall winds were strong, easterly and consistent. The interaction of krill life history with yearly differences in the northward transports of krill and water masses along with sea ice retreat determines the population structure of late-summer krill populations in the DBO5 region near Pt. Barrow. Years with higher proportions of mature krill may provide larger prey to the Pt. Barrow area bowhead whale prey hotspot. The characteristics of prey near Pt. Barrow is dependent on krill abundance and size, large-scale environmental forcing, and interannual variability in recruitment success of krill in the Bering Sea.
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Working PaperFinal cruise report and post-cruise sample processing R/V Gulf Challenger “GC Mixo 23-03”(Woods Hole Oceanographic Institution, 2023-11-28) Alatalo, Philip ; Gast, Rebecca J. ; Tarrant, Ann M. ; Zuñiga, Rodrigo ; Johnson, CameronA primary topic of interest in the field of biological oceanography is the role of planktonic productivity in the global carbon cycle. Over the past 20+ years, the traditional food web of algal production, zooplanktonic consumers and higher trophic level predators has been undergoing revision with a stronger understanding of the contributions made within the microbial loop. Of particular interest has been mixotrophy, the blurring of trophic mode assignments within the microbial eukaryotes. The overall goal of this cruise was to obtain a snapshot of the prevalence of mixotrophy within the Gulf of Maine and the potential contributions of mixotrophs to copepod diets. We proposed to accomplish this goal by sampling water and zooplankton from 3 stations.
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Working PaperFinal cruise report and post-cruise sample processing R/V Gulf Challenger “GC Mixo 23-02”(Woods Hole Oceanographic Institution, 2023-11-28) Alatalo, Philip ; Gast, Rebecca J. ; Tarrant, Ann M. ; Zuñiga, Rodrigo ; Berger, Cory A.A primary topic of interest in the field of biological oceanography is the role of planktonic productivity in the global carbon cycle. Over the past 20+ years, the traditional food web of algal production, zooplanktonic consumers and higher trophic level predators has been undergoing revision with a stronger understanding of the contributions made within the microbial loop. Of particular interest has been mixotrophy, the blurring of trophic mode assignments within the The overall goal of this cruise was to obtain a snapshot of the prevalence of mixotrophy within the Gulf of Maine and the potential contributions of mixotrophs to copepod diets. We proposed to accomplish this goal by sampling water and zooplankton from 3 stations.
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Working PaperFinal cruise report and post-cruise sample processing R/V Gulf Challenger “GC Mixo 23-01”(Woods Hole Oceanographic Institution, 2023-11-28) Alatalo, Philip ; Gast, Rebecca J. ; Tarrant, Ann M.A primary topic of interest in the field of biological oceanography is the role of planktonic productivity in the global carbon cycle. Over the past 20+ years, the traditional food web of algal production, zooplanktonic consumers and higher trophic level predators has been undergoing revision with a stronger understanding of the contributions made within the microbial loop. Of particular interest has been mixotrophy, the blurring of trophic mode assignments within the microbial eukaryotes. The overall goal of this cruise was to obtain a snapshot of the prevalence of mixotrophy within the Gulf of Maine and the potential contributions of mixotrophs to copepod diets. We proposed to accomplish this goal by sampling water and zooplankton from 3 stations.
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Working PaperFinal cruise report and post-cruise sample processing R/V Gulf Challenger “GC Mixo 23-04”(Woods Hole Oceanographic Institution, 2023-11-28) Alatalo, Philip ; Gast, Rebecca J. ; Tarrant, Ann M. ; Zuñiga, RodrigoA primary topic of interest in the field of biological oceanography is the role of planktonic productivity in the global carbon cycle. Over the past 20+ years, the traditional food web of algal production, zooplanktonic consumers and higher trophic level predators has been undergoing revision with a stronger understanding of the contributions made within the microbial loop. Of particular interest has been mixotrophy, the blurring of trophic mode assignments within the microbial eukaryotes. The overall goal of this cruise was to obtain a snapshot of the prevalence of mixotrophy within the Gulf of Maine and the potential contributions of mixotrophs to copepod diets. This cruise was meant to supplement the previous cruise (2303) during which we were only able to sample one station (WB7). The specific goal for this cruise was to sample WB2.
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ArticleConcentration and condition of American lobster postlarvae in small-scale convergences(Wiley, 2023-10-11) Pineda, Jesus ; Tepolt, Carolyn K. ; Starczak, Vicke ; Alatalo, Phil ; Shapiro, SaraInvertebrate larvae are often abundant in the surface ocean, which plays a key role in their dispersal and connectivity. Pelagic microhabitats characterized by small-scale hydrographic variability are complex and ubiquitous in the coastal ocean, but their study is challenging, and they have been largely neglected in meroplankton ecology. Surface convergences, i.e., surface microhabitats featuring convergent horizontal currents, may aggregate the last larval stage of the American lobster and could provide shelter and food for Stage IV postlarvae and thus enhance their condition. We tested these hypotheses by conducting a series of cruises in the southwestern Gulf of Maine in summer 2021, sampling 15 paired sets of potential convergences and off-convergence unstructured habitat. We measured postlarval abundance, surface hydrography, acoustic backscatter, and circulation. Experiments and image analysis compared condition, color, and morphology of postlarvae sampled inside and outside potential convergences. Potential convergences varied in near-surface hydrographic patterns, with most displaying consistency among two transects and diverse patterns in salinity and temperature (e.g., across-convergence gradients with equal or different signs). While the highest postlarval abundances were found in convergences, abundance patterns on and off convergences were not consistent, and another analysis indicated higher abundance in convergences than in a 7-year untargeted surface ocean data set. Experiments indicated no survivorship differences among convergence and non-convergence individuals at two temperatures, while image analyses revealed differences in color and size. Physical measurements and qualitative neuston community analyses indicated substantial heterogeneity among potential convergences. Our results reinforce that small-scale heterogeneities are highly variable but important to the ecology of meroplankton, including the pelagic and neustonic habitats where lobster postlarvae are abundant.
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ArticleHigh resolution analysis of plankton distributions at the Middle Atlantic Bight shelf-break front(Elsevier, 2023-09-07) Hirzel, Andrew J. ; Alatalo, Philip ; Oliver, Hilde ; Petitpas, Christian M. ; Turner, Jefferson T. ; Zhang, Weifeng Gordon ; McGillicuddy, Dennis J.The Middle Atlantic Bight (MAB) is a highly productive ecosystem, supporting several economically important commercial fisheries. Chlorophyll enhancement at the MAB shelf-break front has been observed only intermittently, despite several studies suggesting persistent upwelling at the front. High resolution cross-frontal transects were conducted during three two-week cruises in April 2018, May 2019, and July 2019. Mesoplankton distributions at the front were measured with a Video Plankton Recorder equipped with hydrographic and bio-optical sensors. Zooplankton were also sampled with a Multiple Opening/Closing Net and Environment Sensing System. Each of the three cruises had distinctly different frontal characteristics, with lower variability in frontal position in April 2018 and higher variability in May and July 2019, primarily due to frontal eddies and a Gulf Stream warm core ring, respectively. Eulerian means of all transect crossings within each cruise did not show mean frontal chlorophyll enhancement in April 2018 or July 2019, despite individual crossings showing chlorophyll enhancement in April 2018. Transformation of the April 2018 data into a cross-frontal coordinate system revealed a weak enhancement of chlorophyll and copepods at the front. Mean frontal chlorophyll enhancement was observed in May and was associated with enhancement in the periphery of a frontal eddy rather than the front itself. None of the planktonic categories observed were enhanced at the front in the cross-shelf mean distribution, though diatom chains and copepods were more abundant inshore of the front, particularly in May and July 2019, as well as within the center of a frontal eddy in May. The high variability of the MAB frontal region obscured the impact of ephemeral frontal enhancement in mean observations of April 2018, while frontal eddies contributed to chlorophyll enhancement in mean observations of May 2019. The influence of both argues for the necessity for 3-D models rather than idealized 2-D models to explain frontal behavior and its effects on biological responses.