High-resolution natural recording systems: intercomparisons of the response to interannual climatic variability [abstract]

The goal of this work is to examine the properties of recording mechanisms which are common to continuously recording high-resolution natural systems in which climatic signals are imprinted and preserved as proxy records. These systems produce seasonal structures as an indirect response to climatic variability over the annual cycle. We compare the proxy records from four different high-resolution systems: the Quelccaya ice cap of the Peruvian Andes; composite tree ring growth from southern California and the southwestern United States; and the marine varve sedimentation systems in the Santa Barbara basin (off California, United States) and in the Gulf of California, Mexico. An important focus of this work is to indicate how the interannual climatic signal is recorded in a variety of different natural systems with vastly different recording mechanisms and widely separated in space. These high-resolution records are the products of natural processes which should be comparable, to some degree, to human-engineered systems developed to transmit and record physical quantities. We therefore present a simple analogy of a data recording system as a heuristic model to provide some unifying concepts with which we may better understand the formation of the records. This analogy assumes special significance when we consider that natural proxy records are the principal means to extend our knowledge of climatic variability into the past, beyond the limits of instrumentally recorded data.

Inter-decadal climate variability in the Southern Hemisphere: evidence from Tasmanian tree rings over the past three millennia

EXTRACT (SEE PDF FOR FULL ABSTRACT): The characterization of inter-decadal climate variability in the Southern Hemisphere is severely constrained by the shortness of the instrumental climate records. To help relieve this constraint, we have developed and analyzed a reconstruction of warm-season (November-April) temperatures from Tasmanian tree rings that now extends back to 800 BC. A detailed analysis of this reconstruction in the time and frequency domains indicates that much of the inter-decadal variability is principally confined to four frequency bands with mean periods of 31, 57, 77, and 200 years. ... In so doing, we show how a future greenhouse warming signal over Tasmania could be masked by these natural oscillations unless they are taken into account.

Radiolarian flux in the Santa Barbara Basin as an index of climate variability

Annual radiolarian flux (1954-1986) extrapolated from varved Santa Barbara Basin sediments was compared to instrumental data to examine the effect of interannual climate variability. Paleo-reconstructions over large geographic areas or 10^3 years and longer typically rely on changes in species composition to signal environment or climate shifts. In the relatively short period studied, climate fluctuations were insufficient to significantly alter the assemblage, but there was considerable variability in the total flux of radiolarians. This variability, greatest on 5- to 25-year time scales, appears to be linked to regional climate variability. Total flux correlates to regional California sea surface temperature and the composite of sea level pressure over the Northern Hemisphere for years of high radiolarian flux resembles positive PNA circulation.

Proceedings of the PICES/CoML/IPRC Workshop on Impact of Climate Variability on Observation and Prediction of Ecosystem and Biodiversity Changes in the North Pacific

Table of Contents [pdf, 0.09 Mb] Section I - Presentations and Discussions at Plenary Sessions Introduction and Overview of Workshop Objectives [pdf, 0.07 Mb] Plenary Session Presentations [pdf, 2.23 Mb] Reports of the Breakout Group Discussions [pdf, 0.43 Mb] Closing Plenary Discussion and Recommendations [pdf, 0.11 Mb] Section II - Extended Abstracts of Individual Presentations at Breakout Group Sessions Breakout Group 1: Physical/Chemical Oceanography and Climate [pdf, 6.14 Mb] Breakout Group 2: Phytoplankton, Zooplankton, Micronekton and Benthos [pdf, 28.14 Mb] Breakout Group 3: Fish, Squid, Crabs and Shrimps [pdf, 4.30 Mb] Breakout Group 4: Highly Migratory Fishes, Seabirds and Marine Mammals [pdf, 6.27 Mb] Appendix 1. Workshop agenda [pdf, 0.15 Mb] Appendix 2. List of participants [pdf, 0.13 Mb] (Document pdf contains 216 pages)

Proceedings of the 1998 Science Board Symposium on The Impacts of the 1997/98 El Niño Event on the North Pacific Ocean and Its Marginal Seas

Preface [pdf, 0.01 Mb] James J. O'Brien The big picture - The ENSO of 1997-98 [pdf, 0.01 Mb] James E. Overland, Nicholas A. Bond & Jennifer Miletta Adams Atmospheric anomalies in 1997: Links to ENSO? [pdf, 0.54 Mb] Vladimir I. Ponomarev, Olga Trusenkova, Serge Trousenkov, Dmitry Kaplunenko, Elena Ustinova & Antonina Polyakova The ENSO signal in the northwest Pacific [pdf, 0.47 Mb] Robert L. Smith, A. Huyer, P.M. Kosro & J.A. Barth Observations of El Niño off Oregon: July 1997 to present (October 1998) [pdf, 1.31 Mb] Patrica A. Wheeler & Jon Hill Biological effects of the 1997-1998 El Niño event off Oregon: Nutrient and chlorophyll distributions [pdf, 1.13 Mb] William T. Peterson Hydrography and zooplankton off the central Oregon coast during the 1997-1998 El Niño event [pdf, 0.26 Mb] William Crawford, Josef Cherniawsky, Michael Foreman & Peter Chandler El Niño sea level signal along the west coast of Canada [pdf, 1.25 Mb] Howard J. Freeland & Rick Thomson The El Niño signal along the west coast of Canada - temperature, salinity and velocity [pdf, 0.49 Mb] Frank A. Whitney, David L. Mackas, David W. Welch & Marie Robert Impact of the 1990s El Niños on nutrient supply and productivity of Gulf of Alaska waters [pdf, 0.06 Mb] Craig McNeil, David Farmer & Mark Trevorrow Dissolved gas measurements at Stn. P4 during the 97-98 El Niño [pdf, 0.13 Mb] Kristen L.D. Milligan, Colin D. Levings & Robert E. DeWreede Data compilation and preliminary time series analysis of abundance of a dominant intertidal kelp species in relation to the 1997/1998 El Niño event [pdf, 0.05 Mb] S.M. McKinnell, C.C. Wood, M. Lapointe, J.C. Woodey, K.E. Kostow, J. Nelson & K.D. Hyatt Reviewing the evidence that adult sockeye salmon strayed from the Fraser River and spawned in other rivers in 1997 [pdf,0.03 Mb] G.A. McFarlane & R.J. Beamish Sardines return to British Columbia waters [pdf, 0.34 Mb] Ken H. Morgan Impact of the 1997/98 El Niño on seabirds of the northeast Pacific [pdf, 0.06 Mb] Thomas C. Royer & Thomas Weingartner Coastal hydrographic responses in the northern Gulf of Alaska to the 1997-98 ENSO event [pdf, 0.76 Mb] John F. Piatt, Gary Drew, Thomas Van Pelt, Alisa Abookire, April Nielsen, Mike Shultz & Alexander Kitaysky Biological effects of the 1997/98 ENSO in Cook Inlet, Alaska [pdf, 0.22 Mb] H.J. Niebauer The 1997-98 El Niño in the Bering Sea as compared with previous ENSO events and the "regime shift" of the late 1970s [pdf, 0.10 Mb] A.S. Krovnin, G.P. Nanyushin, M.Yu. Kruzhalov, G.V. Khen, M.A. Bogdanov, E.I. Ustinova, V.V. Maslennikov, A.M. Orlov, B.N. Kotenev, V.V. Bulanov & G.P. Muriy The state of the Far East seas during the 1997/98 El Niño event [pdf, 0.15 Mb] Stacy Smith & Susan Henrichs Phytoplankton collected by a time-series sediment trap deployed in the southeast Bering Sea during 1997 [pdf, 0.21 Mb] Cynthia T. Tynan Redistributions of cetaceans in the southeast Bering Sea relative to anomalous oceanographic conditions during the 1997 El Niño [pdf, 0.02 Mb] Akihiko Yatsu, Junta Mori, Hiroyuki Tanaka, Tomowo Watanabe, Kazuya Nagasawa, Yikimasa Ishida, Toshimi Meguro, Yoshihiko Kamei & Yasunori Sakurai Stock abundance and size compositions of the neon flying squid in the central North Pacific Ocean during 1979-1998 [pdf, 0.11 Mb] O.B. Feschenko A new point of view concerning the El Niño mechanism [pdf, 0.01 Mb] Nathan Mantua 97/98 Ocean climate variability in the northeast Pacific: How much blame does El Niño deserve? [pdf, 0.01 Mb] Vadim P. Pavlychev Sharp changes of hydrometeorological conditions in the northwestern Pacific during the 1997/1998 El Niño event [pdf, 0.01 Mb] Jingyi Wang Predictability and forecast verification of El Niño events [pdf, 0.01 Mb] (Document contains 110 pages)

Report of the PICES-STA Workshop on Monitoring Subarctic North Pacific Variability

The PICES Science Board and the Science and Technology Agency of Japan held a Workshop on Monitoring Subarctic North Pacific Vaiability,October 22-23,1994, in Nemuro,Hokkaido,Japan,in conjunction with the PICES Third Annual Meeting. The Workshop was not intended to discuss process studies or to review the science of the subaractic Pacific,but rather to focus on the longterm monitoring programs required for assessment of the physical and ecological responses to long-term forcing,both natural and man-made. (PDF contains 90 pages)

Variability of Temperature and Salinity in the Middle Atlantic Bight and Gulf of Maine

Monitoring of the waters of the Middle Atlantic Bight and Gulf of Maine has been conducted by the MARMAP Ships of Opportunity Program since the early 1970's. Presented in this atlas are portrayals of the temporal and spatial patterns of surface and bottom temperature and surface salinity for these areas during the period 1978-1990. These patterns are shown in the form of time-space diagrams for single-year and multiyear (base period) time frames. Each base period figure shows thirteen-year (1978-1990) mean conditions, sample variance in the form of standard deviations of the measured values, and data locations. Each single-year figure displays annual conditions, sampling locations, and departures of annual conditions from the thirteen-year means, expressed as algebraic anomalies and standardized anomalies. (PDF file contains 112 pages.)

Seasonal Climatologies and Variability of Eastern Tropical Pacific Surface Waters

Interannual variability caused by the El Nino-Southern Oscillation in the eastern tropical Pacific Ocean (ETP) is analogous to seasonal variability of comparable magnitude. Climatological spatial patterns and seasonal variability of physical variables that may affect the ETP ecosystem are presented and discussed. Surface temperature, surface salinity, mixed layer depth, thermocline depth, thermocline strength, and surface dynamic height were derived from bathythermograph, hydrocast, and CTD data. Surface current velocity, divergence, and upwelling velocity were derived from ship drift reports. Surface wind velocity, wind stress, wind divergence, wind stress curl, and Ekman pumping velocity were derived from gridded pseudostress data obtained from Florida State University. Seasonal maps of these variables, and their deviations from the annual mean, show different patterns of variation in Equatorial (S°S-SON) and Tropical Surface Water (SOlS0N). Seasonal shifts in the trade winds, which affect the strength of equatorial upwelling and the North Equatorial Countercurrent, cause seasonal variations in most variables. Seasonal and interannual variability of surface temperature, mixed layer depth, thermocline depth and wind stress were quantified. Surface temperature, mixed layer depth and thermocline depth, but not local wind stress, are less variable in Tropical Surface Water than in Equatorial Surface Water. Seasonal and interannual variability are close to equal in most of the ETP, within factors of 2 or less. (PDF file contains 70 pages.)

Food habits and dietary variability of pelagic nekton off Oregon and Washington, 1979-1984

The food habits of 20 species of pelagic nekton were investigated from collections made with small-mesh purse seines from 1979-84 off Washington and Oregon. Four species (spiny dogfish, Squalus acanthias; soupfin shark, Galeorhinus zyopterus; blue shark, Prionace glauca; and cutthroat trout, Salmo clarki) were mainly piscivorous. Six species (coho salmon, Oncorhynchus kisutch; chinook salmon, O. tshawytscha; black rockfish, Sebastes melanops; yellowtail rockfish, S. f1avidus; sablefish, Anoplopoma fimbria; and jack mackerel, Trachurus symmetricus) consumed both nektonic and planktonic organisms. The remaining species (market squid, Loligo opalescens; American shad, Alosa sapidissima; Pacific herring, Clupea harengus pallasi; northern anchovy, Engraulis mordax; pink salmon, O. gorbuscha; surf smelt, Hypomesus pretiosus; Pacific hake, Merluccius productus; Pacific saury, Cololabis saira; Pacific mackerel, Scomber japonicus; and medusafish, Icichthys lockingtom) were primarily planktonic feeders. There were substantial interannual, seasonal, and geographic variations in the diets of several species due primarily to changes in prey availability. Juvenile salmonids were not commonly consumed by this assemblage of fishes (PDF file contains 36 pages.)

Burrowing behaviour of signal crayfish, Pacifastacus leniusculus (Dana), in the River Great Ouse, England

Observations were made on crayfish burrows in five locations on the Great Ouse River. The burrow densities and the relative abundance of crayfish were observed. Also, laboratory experiments were carried out in order to study the characteristics and mechanisms of burrowing.

The home range of the signal crayfish in a British lowland river

The signal crayfish Pacifastacus leniusculus (Dana), a native of north-western North America, is now a common resident in some British fresh waters following its introduction to England in 1976 (Lowery & Holdich 1988). In 1984, signal crayfish were introduced into the River Great Ouse, the major lowland river in southern central England, where they have established a large breeding population. This study examines two sites near Thornborough Weir. For the measurement and description of home range a new eletronic microchip system and a modified capture-mark-recapture method were employed. Signal crayfish were marked or tagged to see if they gradually moved away from their burrows. This method proved to be successful for estimating population densities when a section of river is divided into several equidistant linear ”locations”.

The current distribution of signal and native crayfish in the Broadmead Brook, Wiltshire

Signal crayfish (Pacifastacus leniusculus) have existed in the upper reaches of Broadmead Brook in Wiltshire since 200 individuals were introduced at West Kington in 1981. The population has expanded upstream and downstream since this introduction, however, giving rise to concerns that it may potentially threaten the native crayfish population further downstream. Signal crayfish can act as a vector of crayfish plague - a disease caused by the fungus Aphanomyces astaci Schikora which results in almost complete mortality to the native, white-clawed crayfish Austropotamobius pallipes. The native crayfish in Broadmead Brook have not yet succumbed to crayfish plague and are currently free of the disease. However, as signal crayfish appear to out-compete the native species, the native population could still be under threat. In this article, we highlight the findings of previous crayfish surveys on Broadmead Brook and describe work undertaken in summer 2001 to map the current distribution of native and signal crayfish. Finally, options for controlling the spread of signal crayfish are discussed.

Mortality, growth and growth rate variability of striped bass larvae in Chesapeake Subestuaries

In this report we develop age-length keys and derive age-frequency data. We estimate striped bass and white perch mortality and growth rates, based on the otolith-aging analysis. We also report on hatch-date frequencies of striped bass and white perch larvae, and we discuss environmental effects on recruitment potential.

Hypoxic and low pH water in the nearshore marine environments of Monterey Bay, California: characterizing a decade of oxygen and pH, and drivers of variability.

A decade-long time series recorded in southern Monterey Bay, California demonstrates that the shallow, near-shore environment (17 m depth) is regularly inundated with pulses of cold, hypoxic and low pH water. During these episodes, oxygen can drop to biologically threatening levels, and pH levels were lower than expected. Weekly water chemistry monitoring revealed that the saturation state of aragonite (the more soluble form of calcium carbonate) was often below saturation and had a moderate positive relationship with pH, however, analytical and human error could be high. Pulses of hypoxia and low pH water with the greatest intensity arise at the onset of the spring upwelling season, and fluctuations are strongly semidurnal (tidal) and diurnal. Arrival of cold, hypoxic water on the inner shelf typically occurs 3 days after the arrival of a strong upwelling event and appears to be driven by upwelling modulated by internal tidal fluctuations. I found no relationship between the timing of low-oxygen events and the diel solar cycle nor with terrestrial nutrient input. These observations are consistent with advection of hypoxic water from the deep, offshore environment where water masses experience a general decline of temperature, oxygen and pH with depth, and inconsistent with biochemical forcing. Comparisons with concurrent temperature and oxygen time series taken ~20 km away at the head of the Monterey Canyon show similar patterns but even more intense hypoxic events due to stronger semidiurnal forcing there. Analysis of the durations of exposure to low oxygen levels establishes a framework for assessing the ecological relevance of these events. Increasing oceanic hypoxia and acidification of both surface and deep waters may increase the number, intensity, duration and spatial extent of future intrusions along the Pacific coast. Evaluation of the resiliency of nearshore ecosystems such as kelp forests, rocky reefs and sandy habitats, will require consideration of these events.

Season- and depth-dependent variability of a demersal fish assemblage in a large fjord estuary (Puget Sound, Washington)

Fjord estuaries are common along the northeast Pacific coastline, but little information is available on fish assemblage structure and its spatiotemporal variability. Here, we examined changes in diversity metrics, species biomasses, and biomass spectra (the distribution of biomass across body size classes) over three seasons (fall, winter, summer) and at multiple depths (20 to 160 m) in Puget Sound, Washington, a deep and highly urbanized fjord estuary on the U.S. west coast. Our results indicate that this fish assemblage is dominated by cartilaginous species (spotted ratfish [Hydrolagus colliei] and spiny dogfish [Squalus acanthias]) and therefore differs fundamentally from fish assemblages found in shallower estuaries in the northeast Pacific. Diversity was greatest in shallow waters (<40 m), where the assemblage was composed primarily of flatfishes and sculpins, and lowest in deep waters (>80 m) that are more common in Puget Sound and that are dominated by spotted ratf ish and seasonally (fall and summer) by spiny dogfish. Strong depth-dependent variation in the demersal fish assemblage may be a general feature of deep fjord estuaries and indicates pronounced spatial variability in the food web. Future comparisons with less impacted fjords may offer insight into whether cartilaginous species naturally dominate these systems or only do so under conditions related to human-caused ecosystem degradation. Information on species distributions is critical for marine spatial planning and for modeling energy flows in coastal food webs. The data presented here will aid these endeavors and highlight areas for future research in this important yet understudied system.