Cold-water Habitats Research Articles

Effects of climatic change and eutrophication on the glacial relict, Mysis relicta, in Lough Neagh

Summary1. The glacial relict, Mysis relicta, which occurs mainly in unproductive cold water habitats, shows increased mortality rates in temperatures above 16–18 °C. Using a 12‐year data set the growth, mortality and fat stores of Mysis in Lough Neagh, an increasingly hypertrophic lake which lacks a thermal refuge and which is subject to warming, were investigated.2. Mysis showed a significant reduction in fat stores on reaching sexual maturity, contrary to studies elsewhere.3. The contributions of temperature and eutrophication (total phosphorus, chlorophyll‐a concentrations) to growth, mortality and the timing and duration of developmental events were investigated by regression.4. Water temperatures rose between 1994 and 2005 and the time when temperatures exceeded 16 °C doubled over this period. Juvenile and adult growth rates declined and the duration of the juvenile stage increased in warmer years. Eutrophication also affected these variables but, in general, to a lesser extent than temperature.5. Year class strength (YCS) declined by a factor of 10 over the study period. YCS was independent of temperature up to 2000 °C degree days (>4 °C) but declined steeply above that point. Temperature was more important than eutrophication in predicting mortality and YCS. YCS was positively correlated with the length of time water temperature was below 7 °C, the upper temperature for Mysis breeding.6. An established bioenergetic model predicted that water temperature and the timing of embryo release would have appreciable effects on Mysis viability. It also indicated that Mysis would lose mass at summer temperatures, consistent with the observed fat decline.

Cold-water marine natural products

Marine natural products isolated from organisms collected from cold-water habitats are described. Emphasis is on bioactive compounds from tunicates, sponges, microbes, bryozoans, corals, algae, molluscs and echinoderms. Synthetic studies of several important classes of cold-water compounds are highlighted.

Calcareous nannoplankton evolution: a tale of two oceans

Calcareous nannoplankton diversity, evolutionary rates and species longevity show markedly different characters above and below the Cretaceous/Tertiary boundary. Excluding mass extinction events, and the initial origination and radiation, Mesozoic nannoplankton diversity is characterized by relatively continuous increase with low background evolutionary rates and high species longevity. Cenozoic diversity is more variable and features significant Eocene and Neogene diversity declines, with little or no recovery. Cenozoic evolutionary rates are also consistently higher than those of the Mesozoic, and species longevity is low. The response of nannoplankton to climate cooling in the two eras is particularly revealing: cold intervals in the Cretaceous saw greater paleobiogeographical differentiation and high-latitude nannoplankton provinces that supported diversifying communities, whereas, cooling in the Eocene and Neogene coincided with diversity declines, the selective extinction of warm-water taxa, and high-latitude provinces with reduced diversity. It appears likely that the presence of widespread stable, subtropical and tropical oligotrophic water masses promoted the diversification of the broadly K-strategist calcareous nannoplankton (and dinoflagellates) for much of the Mesozoic and into the early Paleogene. The switch to an icehouse climate, however, transformed the oceans, favouring the r-strategist diatoms at the expense of the other phytoplankton groups. The profound Eocene cooling established new, cold-water habitats that limited calcareous nannoplankton habitation and diversification, but promoted diatom expansion and diversification at high latitudes. Diatoms became the most competitive of the phytoplankton groups, flourishing in all environments but particularly those with high and pulsed nutrient inputs, although their expansion may also have been aided by tectonic and biological factors that increased the flux of biolimiting silica to the oceans.

Marine reptiles from the Lower Cretaceous (Aptian) deposits of White Cliffs, southeastern Australia: implications of a high latitude, cold water assemblage

Marine reptile remains, represented by several fragmentary skeletons and isolated elements, are described from the Lower Cretaceous (Aptian) southern high latitude deposits (Doncaster Member, Wallumbilla Formation) of White Cliffs in southeastern Australia. The specimens are attributable to at least three families of plesiosaur (Elasmosauridae, Polycotylidae and Pliosauridae) and probably one family of ichthyosaur (Ophthalmosauridae). Polycotylid material from White Cliffs is amongst the oldest from anywhere in the world, and could point to an eastern Gondwanan origin for the group. Interestingly, the White Cliffs marine reptile fossils occur in association with palaeoclimatic indicators denoting seasonally very cold to near freezing conditions. This differs markedly from the climate regimes typically tolerated by modern aquatic reptiles but suggests that some Mesozoic taxa were able to cope with low temperature environments. Exactly what adaptations facilitated their survival is unknown. However, various strategies including elevated metabolic rates, rapid growth and/or seasonal migration/hibernation might have enabled their exploitation of cold water habitats along the southern coastal margin of the Australian Cretaceous epicontinental seaway.

Limnological and Climatic Environments at Upper Klamath Lake, Oregon during the past 45 000 years

Upper Klamath Lake, in south-central Oregon, contains long sediment records with well-preserved diatoms and lithological variations that reflect climate-induced limnological changes. These sediment archives complement and extend high resolution terrestrial records along a north–south transect that includes areas influenced by the Aleutian Low and Subtropical High, which control both marine and continental climates in the western United States. The longest and oldest core collected in this study came from the southwest margin of the lake at Caledonia Marsh, and was dated by radiocarbon and tephrochronology to an age of about 45 ka. Paleolimnological interpretations of this core, based upon geochemical and diatom analyses, have been augmented by data from a short core collected from open water environments at nearby Howards Bay and from a 9-m core extending to 15 ka raised from the center of the northwestern part of Upper Klamath Lake. Pre- and full-glacial intervals of the Caledonia Marsh core are characterized and dominated by lithic detrital material. Planktic diatom taxa characteristic of cold-water habitats (Aulacoseira subarctica and A. islandica) alternate with warm-water planktic diatoms (A. ambigua) between 45 and 23 ka, documenting climate changes at millennial scales during oxygen isotope stage (OIS) 3. The full-glacial interval contains mostly cold-water planktic, benthic, and reworked Pliocene lacustrine diatoms (from the surrounding Yonna Formation) that document shallow water conditions in a cold, windy environment. After 15 ka, diatom productivity increased. Organic carbon and biogenic silica became significant sediment components and diatoms that live in the lake today, indicative of warm, eutrophic water, became prominent. Lake levels fell during the mid-Holocene and marsh environments extended over the core site. This interval is characterized by high levels of organic carbon from emergent aquatic vegetation (Scirpus) and by the Mazama ash (7.55 ka), generated by the eruption that created nearby Crater Lake. For a brief time the ash increased the salinity of Upper Klamath Lake. High concentrations of molybdenum, arsenic, and vanadium indicate that Caledonia Marsh was anoxic from about 7 to 5 ka. After the mid-Holocene, shallow, but open-water environments returned to the core site. The sediments became dominated (>80%) by biogenic silica. The open-water cores show analogous but less extreme limnological and climatic changes more typical of mid-lake environments. Millennial-scale lake and climate changes during OIS 3 at Upper Klamath Lake contrast with a similar record of variation at Owens Lake, about 750 km south. When Upper Klamath Lake experienced cold-climate episodes during OIS 3, Owens Lake had warm but wet episodes; the reverse occurred during warmer intervals at Upper Klamath Lake. Such climatic alternations apparently reflect the variable position and strength of the Aleutian Low during the mid-Wisconsin.

Influences of Temperature and Environmental Variables on the Distribution of Bull Trout within Streams at the Southern Margin of Its Range

The bull trout Salvelinus confluentus is believed to be among the most thermally sensitive species in coldwater habitats in western North America. We conducted a comprehensive field assessment of thermal habitat associations throughout the southern margin of the species' range. We developed models of thermal habitat associations using two data sets representing a geographically diverse range of sites and sampling methods. In both data sets, maximum temperature was strongly associated with the distribution of bull trout. In spite of the potential biases in these data sets, model predictions were similar. In both cases, the probability of the occurrence of bull trout exceeded 50% when the maximum daily temperature was less than 14-16°C, a result that is consistent with recent laboratory-based thermal tolerances. In one data set, we modeled the association between the distribution of bull trout and environmental variables, including temperature, instream cover, channel form, substrate, and the abundance of native and nonnative salmonid fishes. Only temperature was strongly associated with the distribution of bull trout. Our results and related studies of landscape habitat associations suggest that conservation efforts for bull trout would benefit from a focus on maintaining and restoring large and interconnected coldwater habitats.

The influence of glacial runoff on stream macroinvertebrate communities in the Taillon catchment, French Pyrénées

1. Benthic communities were sampled from five sites within a glacial catchment in the Cirque du Gavaranie, French Pyrénées, over two consecutive years (i) to investigate whether longitudinal patterns in zoobenthic communities exist downstream of a glacial margin and (ii) to identify the principal environmental variables influencing such patterns.2. There was a distinct zonation of communities with increasing distance from the glacial margin. Ordination of the zoobenthic distribution indicated sites were separated by the relative contributions of taxa rather than their presence or absence. A shift in community composition and diversity separated a kryal type community dominated by Diamesa spp., Prosimulium spp., Eriopterini and Empididae at ≥2200 m a.s.l., from a more rhithral community of Orthocladiinae, Ephemeroptera, Plecoptera and Trichoptera at 1900 m a.s.l.3. Chironomidae showed a defined gradient in distribution from Pseudokiefferiella parva and Diamesa latitarsis groups close to the glacier, through D. zernyi and D. cinerella groups, Orthocladius, Parametriocnemus and Micropsectra further downstream with Rheocricotopus, Corynoneura and Nilotanypus furthest from the glacial margin. Diamesa cinerella/zernyi group was the most euryzonal taxon.4. Gradients in channel and hydraulic stability, groundwater input and mean water temperature were identified as the principal environmental variables associated with the downstream distribution gradient of zoobenthos. Diamesa, Empididae, Eriopterini and Nematoda were most tolerant of channel and hydraulically unstable and cold water habitats. Simuliidae (Prosimulium), Crenobia alpina, Rhyacophila, Chaetopterygini, Drusus rectus, Capnioneura, Orthocladius and Parametriocnemus were associated with intermediate conditions. Corynoneura, Tanypodinae, Perlidae, Chloroperlidae, Agapetus fuscipes and Coleoptera were least tolerant of channel and hydraulic instability and low water temperature.

Development of 18S rRNA-targeted Oligonucleotide Probes for Specific Detection of Hartmannella and Naegleria in Legionella – positive Environmental Samples

Aquatic protozoa are natural hosts of the human pathogen Legionella pneumophila. The fluorescence labeled 16S rRNA-targeted oligonucleotide probe LEGPNE1 has recently been shown to specifically detect extracellular legionellae as well as intracellular legionellae parasitizing protozoa. In this study we designed oligonucleotide probes which are complementary to distinct regions of the 18S rRNA of the Legionella host organisms of the genera Hartmannella and Naegleria. The specificity of the probes, HART498 and NAEG1088, was tested by in situ hybridization of various laboratory reference strains. In order to evaluate the fluorescent probes for environmental studies three selected Legionella-positive cold water habitats were examined for the presence of these protozoa. Traditional culture methods followed by morphological identification revealed an almost consistent presence of Naegleria spp. in cold water habitats. Other protozoa species including Acanthamoeba spp., Echinamoeba spp., Hartmannella spp., Platyamoeba placida, Saccamoeba spp., Thecamoeba quadrilineata, and Vexillifera spp. were found sporadically. Concomitant analysis of the pH, conductivity and temperature of the water samples revealed no preference of Legionella or the respective protozoa for certain environmental conditions. The specificity of the newly designed 18S rRNA probes demonstrates that they are valuable and rapid tools for the identification of culturable environmental protozoa.

Halicryptus higginsi n.sp. (Priapulida): A Giant New Species from Barrow, Alaska

A new species of Priapulida was discovered from the Beaufort Sea near Barrow, Alaska. Following an unusually strong autumnal storm, 30 adult specimens of Halicryptus higginsi n.sp. were collected, many alive, from intertidal beaches Additional specimens were found in museum collections misidentified as Halicryptus spinulosus von Siebold 1849. The new species represents the 11th priapulid species described since 1968 and increases the number of described extant species of Priapulida to 18. While all other recently described priapulids have been meiofaunal, Halicryptus higginsi n.sp. is macrofaunal and the largest extant priapulid species, with one specimen being 39 cm long in a contracted condition. Additional key words: arctic, benthos In recent years the concept of the marine phylum Priapulida has changed radically, from that of a macrobenthic, cold-water taxon, to one that is more speciose in the tropical meiofauna. Before 1968, only 7 extant species were known and additional species had been described from the fossil record; all extant species were macrobenthic and found only in cold-water habitats (Higgins et al. 1993). In 1968 the first meiobenthic priapulid, Tubiluchus corallicola VAN DER LAND 1968, was described from a tropical, shallowwater habitat (van der Land 1968). Since 1968 an additional 9 priapulid species, all meiobenthic and mostly inhabitants of tropical, shallow-water sediments, have been described. Tubiluchus arcticus ADRIANOV, MALAKOV, CHESUNOV, & TSETLIN 1989 is the only cold-water species that has been described in recent years, and it is a meiofaunal priapulid that inhabits shallow-water sediments in the arctic (Adrianov et al. 1989). During a survey of museum specimens of priapulids, one of us (VS) discovered that specimens in the United States National Museum of Natural History, Smithsonian Institution, misidentified as Halicryptus spinulosus von Siebold from Barrow, Alaska, had been used for scanning electron microscopy (Merriman 1981) and instead represented a new and undescribed congener. Subsequent to the museum discovery we found larvae and juveniles of the undescribed species a Author for correspondence. E-mail: fftcs@uaf.edu in the shallow subtidal during two expeditions to Barrow, Alaska in 1991 and 1992, but did not find adults of the new species. Following an unusually strong autumnal storm in 1993, 30 adult specimens of Halicryptus higginsi n.sp. were collected, many alive, from intertidal beaches near Barrow. In this paper we describe the new species and compare it with H. spinulosus. The larvae will be described in a separate pub-

Predation, herbivory, and kelp evolution

We propose that the kelps (Laminariales) radiated in the North Pacific following the onset of late Cenozoic polar cooling. The evidence is that (1) extant kelps occur exclusively in cold-water habitats; (2) all but one of 27 kelp genera occur in the North Pacific, 19 of these exclusively; and (3) limpets and herbivorous marine mammals obligately associated with kelps or other stipitate brown algae appeared late in the Cenozoic, even though more generalized forms of both groups are much older. We propose, further, that sea otters and perhaps other groups of benthic-feeding predatory mammals, whose late Cenozoic distributions all were limited to the North Pacific, created an environment for the evolution of kelps in which the intensity of herbivory was unusually low. We hypothesize that this interaction created predictable differences among habitats in the intensity of herbivory on several spatial scales, with resulting trade-offs between anti-herbivore defenses and plant competitive abilities in their respective floras. Sea otters incur time and energy costs for diving, resulting in depth-related reductions to foraging efficiency and thus increased sizes and densities of herbivorous sea urchins. Thus, the deep-water flora is well defended, but competitively subordinate, compared with the shallow-water flora. Similarly, we argue that during the same period of earth history, predation had less of a limiting influence on herbivorous invertebrates in the temperate southwestern Pacific. We hypothesize that (1) consequent biogeographical differences in the intensity of herbivory may have selected the phenolic-rich brown algal flora in temperate Australia/New Zealand; and (2) tightly coevolved plant/herbivore interactions may explain why Australian and New Zealand herbivores are undeterred by phenolics and why other classes of secondary compounds in the Australian/New Zealand flora significantly deter herbivores.

Turbidity as a Water Quality Standard for Salmonid Habitats in Alaska

Abstract Evidence both of trophic level changes induced by reduction in light penetration and of more direct effects of sediment and turbidity on aquatic life indicates that turbidity constitutes a valid and useful water quality standard that can be used to protect aquatic habitats from sediment pollution. A review of studies conducted in Alaska and elsewhere indicated that water quality standards allowing increases of 25 or 5 nephelometric turbidity units above ambient turbidity in clear coldwater habitats provide moderate and relatively high protection, respectively, for salmonid fish resources in Alaska. Even stricter limits may be warranted to protect extremely clear waters, but such stringent limits apparently are not necessary to protect naturally turbid systems.

Size composition of lysianassid amphipods in cold and warm water habitats

Size composition of lysianassid amphipods in cold and warm water habitats

Deep-sea ahermatypic scleractinian corals: isotopic composition of the skeleton

13C/ 12C and 18O/ 16O ratios of the skeletal aragonite deposited by ahermatypic scleractinian corals were measured for 220 separate specimens taken from marine environments ranging from deep-sea and/or cold water habitats to the warm waters of tropical coral reefs. Each sample is depleted in 13C and 18O relative to calcium carbonate in isotopic equilibrium with the ambient sea water system. Despite apparent isotopic disequilibrium, systematic relationships between isotopic composition and environmental parameters are clearly apparent, permitting the use of stable isotope ratio data for non-reef-building corals in paleoecological and paleoenvironmental interpretations if certain precautions are taken. Skeletal δ 18O and water temperature are closely related for the ahermatypes over the entire temperature range of present-day oceans (∼ 0–30°C). The temperature versus δ 18O curve is parallel to that for CaCO 3 in oxygen isotopic equilibrium with sea water, but it is displaced 2·4 per mil towards lower δ 18O. These findings have implications concerning the mechanism of calcification in the scleractinian corals. Oxygen isotope ratios recorded in the skeletons of deep-sea ahermatypes may be utilized as geochemical indicators of temperature and/or depth.

Age and Growth of the Brook Trout in a Wyoming Beaver Pond

PARTLY because of its preference for coldwater habitats, the brook trout (Salvelinus fontinalis) has been widely introduced into spring creeks, beaver ponds, and high altitude lakes and streams in western North America. Beaver ponds have always been one of the favorite planting sites. The inaccessibility of these populations of brook trout, to fishermen and biologists alike, has placed their management on a conjectural basis in most instances. The literature on brook trout contains little information on populations in beaver ponds. Beaver-trout relationships have been the subject of debate, but with almost no supporting data. This paper, in presenting information on a relatively undisturbed brook trout population in a small Wyoming beaver pond, attempts to remedy some of these deficiencies.