Abyssal Time-Series Studies at Station M

Research Group: Ken Smith (Senior Scientist), Alana Sherman (Senior Engineer), Jacob Ellena (Research Technician), Michael Vardaro (Postdoctoral Fellow), Stephanie Wilson (Postdoctoral Fellow), Henry Ruhl (Collaborator)

The primary emphasis of our research is an ongoing long time-series project that has been conducted over 20 years from 1989 to the present at “Station M” (34o 50’N, 123o 00’W; 4,100 m depth) 220 km west of the central California coast. This deep-sea  time-series study is one of two currently being conducted in the abyssal ocean.

The Station M study represents the most detailed investigation of any abyssal area in the world ocean. Over this 20-year time series study, we have monitored continuously the flux of sinking particulate matter through the benthic boundary layer (bottom 600 m of the water column and sea floor) and employed time-lapse photography to record dynamic benthic processes. The sinking flux of particulate organic carbon entering the benthic boundary layer has been used as an estimate of food supply to the sea floor and compared with seasonal measurements of sediment community oxygen consumption, an estimate of food consumption by the benthic community.

 

Camera Tripod readied for deployment	Bottom of the sea floor at Station M	Sediment Trap being deployed

The sea floor at Sta. M is characterized by silty-clay sediments with little topographic relief (< 100m over 1600 km2). Surface waters of the California Current overlying this site have well-developed plumes of chlorophyll in the spring that persist into summer and exhibit inter-annual variability. This temporal signal in surface production is observed throughout the water column and into the sediments.

Measurements at Station M are being made with a variety of instruments. Sinking particulate matter, consisting of phytoplankton detritus, zooplankton fecal material and amorphous flocculent material, is collected with sequencing sediment traps moored at 50 and 600 m above bottom. Current flow has been measured with current meters at 2, 50 and 600 m above bottom. The activities of mobile animals just above the sea floor (e.g. grenadier fishes, jellyfish and sea cucumbers) and on the sediment (e.g. brittle stars, sea cucumbers, sea urchins) are observed using a time-lapse camera tripod. Photographic transects of the sea floor are taken either by a sled equipped with a camera that is towed behind a research ship or by cameras mounted on remote operated vehicles. Oxygen consumption, a measure of biological activity, of organisms living in the sediments on the sea floor is measured using a Free Vehicle Grab Respirometer (FVGR) with grabs that retrieve the sediments for faunal examination and chemical analyses.  A newly developed benthic Rover, can now measure sediment community oxygen consumption along a transect of < 50 sites during autonomous deployments up to six months.

Camera Sled being recovered	ROV Doc Ricketts aboard R/V Western Flyer	Free Vehicle Grab Respirometer

 

Significant findings of these studies at Sta. M are listed below:

1. Sinking particulate organic carbon fluxes to abyssal depths and through the benthic boundary layer showed seasonal peaks in summer and fall with considerable inter-annual variability.

2. Sinking particulate organic matter fluxes at 600 m above bottom were correlated with the Bakun upwelling index, revealing a time lag of approximately 2 to 3 months between these climatically mediated events at the surface and the particulate fluxes (food supply) at 3500 m depth.

3. A strong correlation exists between surface ocean processes and the supply of particulate organic matter to the abyssal sea floor at Sta. M.

4. Epibenthic megafauna on the sea floor, including holothurians and echinoids, are very conspicuous in time-lapse camera and camera sled transects. Dramatic shifts in population abundances of the dominant epibenthic species are significantly correlated to El Nino/La Nina events expressed in the Northern Oscillation index when lagged by 14 to 18 months.

5.Epibenthic megafauna and smaller macrofauna abundances are correlated to the particulate organic carbon (food supply) entering the benthic boundary layer when examined over periods of time exceeding a decade.

6. Sediment community oxygen consumption, a measure of food utilization by the benthic community, was highest in summer and lowest in winter.

7. Over an extended time series, the estimate of food utilization by the benthic community exceeded the supply of food.

8. Fluctuations in food supply driven by climate variation are ultimately linked to abyssal community structure and processes.

Recent Publications concerning Station M

2010    S.E. Wilson, , H.A. Ruhl, K.L. Smith, Jr. Seasonal and interannual contribution of zooplankton fecal pellets to carbon flux in the abyssal northeast Pacific. Limnol. Oceanogr. (submitted).

2010    M.F. Vardaro. Genetic and anatomic relationships among three morphotypes of the echinoid Echinocrepis rostrata. Invert. Biol. 129, 368-375.

2010    I. Kouridaki, P.N. Polymenakou, A. Tselepides, M. Mandalakis, K.L. Smith, Jr. Phylogenetic diversity of sediment bacteria from the deep northeastern Pacific Ocean: comparison with the deep eastern Mediterranean Sea. International Microbiol. 13, 143-150.

2009    K.L. Smith, Jr., H.A. Ruhl, B.J. Bett, D.S.M. Billett, R.S. Lampitt and R.S. Kaufmann. Climate, carbon cycling, and deep-ocean ecosystems. Proc. Nat. Acad. Sci. 106, 19211-19218.

2009    N. D. Holland, W.J. Jones, J. Ellena, H.A. Ruhl and K.L. Smith, Jr. A new deep-sea species of epibenthic acorn worm (Hemichordata, Enteropneusta). Zoosystema, 31, 333 – 346.

2009    J.C. Drazen, C.F. Phleger, M.A. Guest, P.D. Nichols. Lipid composition and diet inferences in abyssal macrourids of the eastern North Pacific. Mar. Ecol. Prog. Ser. 387,1-14.

2009    M.F. Vardaro, H.A. Ruhl and K.L. Smith, Jr. Climate variation, carbon flux, and bioturbation in the abyssal North Pacific. Limnol. Oceanogr., 54, 2081-2088.

2009    A.D. Sherman and K.L. Smith, Jr. Deep-sea benthic boundary layer communities and food supply:  A long-term monitoring strategy. Deep-Sea Res. II, 56, 1754-1762.

2009    P.R. McGill, A.D. Sherman, B.W. Hobson, R.G. Henthorn and K.L. Smith, Jr. Initial deployments of the Rover, an autonomous bottom-transecting instrument platform. J. Ocean. Tech. 4, 9-26.

2009    S.R. Beaupre, E.R.M. Druffel. Source Constraining the propagation of bomb-radiocarbon through the dissolved organic carbon (DOC) pool in the northeast Pacific Ocean. Deep-Sea Res. (1 Oceanogr. Res. Pap.) 56(10) 1717-1726.

2008    H.A. Ruhl, J. A. Ellena and K.L. Smith, Jr. Connections between climate, food limitation, and carbon cycling in abyssal sediment communities. Proc. Nat. Acad. Sci.105, 17006-17011.

2008    J.C. Drazen, B.N. Popp, C.A. Choy, T. Clemente, L. DeForest and K.L. Smith, Jr. Bypassing the abyssal benthic food web: Macrourid diet in the eastern North Pacific inferred from stomach content and stable isotopes analyses. Limnol. Oceanogr. 53, 2644-2654.

2008    E.R.M. Druffel, J.E. Bauer, S. Griffin, et al. Dissolved inorganic radiocarbon in the North Pacific Ocean and Sargasso Sea. Deep-Sea Res. (1 Oceanogr. Res. Pap.) 55(4),451-459.

2008    K.L. Smith, Jr., H.A. Ruhl, R.S. Kaufmann, M. Kahru. Tracing abyssal food supply back to upper-ocean processes over a 17-year time series in the NE Pacific. Limnol. Oceanogr. 53, 2655-2667.

2008    J.A.T. Booth, H.A. Ruhl, L.L. Lovell, K.L. Smith, Jr. Size frequency dynamics of NE Pacific abyssal ophiuroids (Echinodermata: Ophiuroidea). Mar. Biol. 154,933-941.

2008    H.A. Ruhl. Community change in the variable resource habitat of the abyssal NE Pacific. Ecology 89, 991-1000.

2008    A.K. Sweetman, U. Witte. Macrofaunal community composition, food web structure and short-term response to a simulated phytodetrital pulse in the abyssal northeast Pacific Ocean. Mar. Ecol. Prog. Ser. 355,73-84.

2007    H. A. Ruhl. Abundance and size distribution dynamics of abyssal epibenthic megafauna in the northeast Pacific. Ecology 88,1250-1262.

2007    P.R. McGill, A.D. Sherman, B.W. Hobson, R.G. Henthorn, A.C. Chase, K.L. Smith, Jr.  Initial Deployments of the Benthic Rover, an Autonomous Bottom-Transecting Instrument Platform for Long-Term Measurements in Deep Benthic Environments. Proceedings of the MTS/IEE Oceans Conference, Vancouver, British Columbia.

2007    M.F. Vardaro, D. Parmley and K.L. Smith, Jr. A study of possible “reef effects” caused by a long-term time-lapse camera in the deep North Pacific. Deep-Sea Res. I. 54, 1231-1240.

2007    J. Jones, E. Macpherson. Molecular phylogeny of the East Pacific squat lobsters of the genus Munidopsis (Decapoda: Galatheidae) with the descriptions of seven new species. J. Crust. Biol. 27(3):477-501.

2007    S.R. Beaupre, E.R.M. Druffel, S. Griffin. A low-blank photochemical extraction system for concentration and isotopic analyses of marine dissolved organic carbon Limnol. Oceanogr.:Methods 5,174-184.

2007    E.A. Hendrycks. A new species of Valettiopsis Holmes, 1908 (Crustacea : Gammaridea : Lysianassoidea) from abyssal waters off California. Zootaxa 1501,45-56.

2006    D.M. Bailey, H.A. Ruhl and K.L. Smith, Jr. Long-term changes in benthopelagic fish abundance in the abyssal Northeast Pacific Ocean. Ecology 87, 549-555.

2006    K.L. Smith, Jr., R.J. Baldwin, H.A. Ruhl, M. Kahru, B.G. Mitchell and R.S. Kaufmann. Climate effect on food supply to depths greater than 4,000 meters in the northeast Pacific. Limnol. Oceanogr. 51, 166-176.

2005    K.L. Smith, Jr., N.D. Holland and H.A. Ruhl. Enteropneust production of spiral fecal trails on the deep-sea floor observed with time-lapse photography. Deep-Sea Res. I. 52, 1228-1240.

2004    J. Hwang, E.R.M. Druffel, S. Griffin, K.L. Smith, Jr., R.J. Baldwin and J.E. Bauer. Temporal variability of delta 14C, 13C and C/N in sinking particulate organic matter at a deep time-series station in the Northeast Pacific Ocean. Global Biogeochem. Cycl. 18, GB4015, doi:10.1029/2004GB002221.

2004    H.A. Ruhl and K.L. Smith, Jr. Shifts in deep-sea community structure linked to climate and food supply. Science 305, 513-515.

2004    E.C. Fisher, R.S. Kaufmann and K.L. Smith, Jr. Variability of epipelagic macrozooplankton/micronekton community structure in the NW Weddell Sea, Antarctica (1995 – 1996). Mar. Biol. 144, 345-360.

2004    I.G. Priede, A.R. Deary, D.M. Bailey and K.L. Smith, Jr. Low activity and seasonal change in population size structure of grenadiers in the oligotrophic abyssal central North Pacific Ocean. J. Fish Biol. 63, 187-196.

2004    J.S. Hwang, E.R.M. Druffel. Lipid-like material as the source of the uncharacterized organic carbon in the ocean? Science 299, 881-884.

2004    E.A. Hendrycks, K.E. Conlan. New and unusual abyssal gammaridean Amphipoda from the north-east Pacific. J. Nat. Hist. 37(19),2303-2368.

2004   J.C. Drazen. A seasonal analysis of the nutritional condition of deep-sea macrourid fishes in the north-east Pacific. J. Fish. Biol. 60(5),1280-1295.

2002    K.L. Smith, Jr., R.J. Baldwin, D.M. Karl and A. Boetius. Benthic community responses to   pulses in pelagic food supply: North Pacific Subtropical Gyre. Deep-Sea Res. I. 49, 971-990.