Anchor Ice Formation Research Articles

Stream Gradient‐Related Movement and Growth of Atlantic Salmon Parr during Winter

AbstractThere has been considerable focus on winter studies of Atlantic salmonSalmo salarparr during the last two decades. However, a lack of knowledge exists about the linkage between the physical conditions, including ice, and parr behavior in flow environments during the cold season. In this study, the movement and growth of Atlantic salmon parr were studied during winter in two stream sections with different gradients (0.3% and 1.8%) in a small natural river. Passive integrated transponder (PIT) technology was implemented by using both fixed antennae and mobile tracking devices. In the low‐gradient section, the formation of surface ice dominated and created stable conditions, whereas in the high‐gradient section, the formation of anchor ice and anchor ice dams occurred periodically and produced a dynamic environment. The results indicated a relationship between parr movement and river gradient. Movement by parr was negatively correlated with time from autumn to late winter but increased as spring approached. The level of movement was considered low (median = 0.9 m), but larger movements (up to 125.6 m) were recorded, indicating individual variation. Furthermore, parr inhabiting the low‐gradient section with the static ice formation exhibited larger movement than parr in the high‐gradient section with dynamic ice formation. Parr showed high site fidelity to both high‐ and low‐gradient sections but were less attracted to pool habitats. Finally, from late autumn to spring, parr demonstrated a specific growth rate close to 0.0%, indicating suitable conditions in both sections. As this study implies, the complexity of physical conditions during winter may lead to variability in individual fish response (i.e., movements). However, the results also imply that winter is not a limiting factor in parr performance if fish have access to suitable cover, such as areas with low substrate embeddedness.

Annual warming episodes in seawater temperatures in McMurdo Sound in relationship to endogenous ice in notothenioid fish

We obtained two years (1999–2001) of continuous, high resolution temperature and pressure data at two near-shore shallow water sites in McMurdo Sound, Ross Sea. Contrary to the long-held assumption of constant freezing conditions in the Sound, these records revealed dynamic temperature fluctuations and substantial warming during January to March reaching peak water temperatures of about −0.5°C. They also revealed that excursions above −1.1°C, the equilibrium melting point of ice in Antarctic notothenioid fish, totalled 8–21 days during the summer. Microscopic ice crystals are known to enter these fish but ice growth is arrested by antifreeze proteins. Prior to this study there were no known mechanisms of eliminating accumulated endogenous ice. The warm temperature excursions provide for the first time a possible physical mechanism, passive melting, for ice removal. The continuous records also showed a correlation between tidal pressures and cold temperature episodes, which suggests the influx of cold currents from under the Ross Ice Shelf may provide a mechanism for ice crystal nucleation as the source of the ice in McMurdo Sound fish. The accumulation of anchor ice on one logger caused it to float up which was recorded as a decrease in pressure. This is the first evidence for the time of onset of anchor ice formation in McMurdo Sound.

Discussion of “Laboratory Study of Anchor Ice Growth” by J. C. Doering, L. E. Bekeris, M. P. Morris, K. E. Dow, and W. C. Girling

As a student of anchor ice phenomena, I read the paper with great interest. Although anchor ice has long been recognized ~Barnes 1928!, the formation of anchor ice is still something of an enigma. Identification of relationships between easily measured flow characteristics and anchor ice phenomena would be a great boon to everyone who deals with anchor ice. The authors conducted a series of 12 laboratory flume experiments to search for such relationships. They conclude that their data suggests two such relationships: ~1! a relationship between the Froude number of the flow and anchor ice ‘‘growth,’’ and ~2! a relationship between the flow Reynolds number and anchor ice release. Based on the authors’ observations and data, I argue that both of these conclusions are flawed. The authors define the anchor ice growth rate as the increase of anchor ice thickness over time, expressed as millimeters per hour. They found that the most rapid anchor ice growth occurred at a Froude number of 0.27. Increasing anchor ice thickness over time would be a valid measure of growth if the anchor ice had the same density in every experiment. However, the authors note that ‘‘qualitative observations indicate that the density of anchor ice increases for increasing Froude number’’ ~p. 65!. Based on this observation, it would seem obvious that anchor ice growth cannot be defined by thickness alone. Instead, growth should be defined by the change in anchor ice mass, because the denser anchor ice seen in higher Froude number experiments must contain more ice ~i.e., greater masses of ice! than the ‘‘fluffy patches of anchor ice observed for a low Froude number run’’ ~p. 63!. The technique the authors used to determine anchor ice growth rates has a built-in inconsistency ~varying ice density! so any observed relationship is meaningless. The authors’ other major conclusion is that for Reynolds numbers less than approximately 42,000 anchor ice was released from the bed. However, it appears the authors made an error in calculating the Reynolds numbers. The authors’ data ~from their Table 1! on experiment number ~run!, water depth ~h!, current velocity (Ve), Reynolds number ~R! and anchor ice release are shown in Table 1. Also shown are my calculations for the Reynolds numbers (Rnew). I use h and Ve , from the authors, a density of 1,000 kg/m 3 , and a viscosity of 1.787 310 23 kg/~m/s! to calculate the Reynolds number. Based on a comparison of the authors’ and my calculated Reynolds numbers, it appears that the column containing the Reynolds number in the authors’ original paper somehow got

Aspects of river ice hydrology in Japan

AbstractRivers in northern Japan are subjected to ice formation each winter. They are typically very steep with rapid changes in channel slope. As a result, ice covers are usually discontinuous with open water sections. Winter discharges in Japanese rivers are usually very small. Water temperature and ice production in these streams are very sensitive to the change in air temperature. The open water sections enable the formation of frazil and anchor ice during the winter. Owing to the relatively stable winter weather and heavy snow cover, premature break‐up and ice jams rarely occur, even though the channel geometry of these rivers is favourable for their occurrence. In this paper, hydrometeorological factors related to ice‐cover formation, frazil and anchor‐ice development, and ice‐jam formation, as well as measurements of the undercover discharge in rivers in northern Japan are discussed. Copyright © 2002 John Wiley & Sons, Ltd.

Anchor-Ice Formation and Ice Rafting in Southwestern Lake Michigan, U.S.A.

ABSTRACT Anchor ice, i.e., ice attached to the bed in a lake, stream, or ocean, is common in the nearshore zone of southwestern Lake Michigan during winter. Lacustrine anchor ice has at least four distinct morphologies and was observed on sand, pebble, and boulder substrates in water depths to 4 m, the limit of diving traverses. The maximum depth of anchor ice formation may be much greater. Anchor ice is released from the lake bed on mornings following formation events. Released, floating anchor ice carries sediment to the water surface. This sediment is ice-rafted along shore and offshore under the influence of prevailing winds. We estimate that 0.85 m3 of sand per meter of beach is being removed from the nearshore zone of southwestern Lake Michigan by anchor ice annually. Melting ice drops this sand in deep water far from shore. This is a significant loss of sand from the sediment-starved nearshore zone of southwestern Lake Michigan.

Anchor-Ice Formation and Ice Rafting in Southwestern Lake Michigan, U.S.A.

Anchor-Ice Formation and Ice Rafting in Southwestern Lake Michigan, U.S.A.

Role of Stream Ice on Fall and Winter Movements and Habitat Use by Bull Trout and Cutthroat Trout in Montana Headwater Streams

We used radiotelemetry and underwater observation to assess fall and winter movements and habitat use by bull trout Salvelinus confluentus and westslope cutthroat trout Oncorhynchus clarki lewisi in two headwater streams in the Bitterroot River drainage, Montana, that varied markedly in habitat availability and stream ice conditions. Bull trout and cutthroat trout made extensive (>1 km) downstream overwintering movements with declining temperature in the fall. Most fish remained stationary for the remainder of the study (until late February), but some fish made additional downstream movements (1.1–1.7 km) in winter during a low-temperature (⩽1°C) period marked by anchor ice formation. Winter movement was more extensive in the mid-elevation stream where frequent freezing and thawing led to variable surface ice cover and frequent supercooling (<0°C). Habitat use of both species varied with availability; beaver ponds and pools with large woody debris were preferred in one stream, and pools with boulders were preferred in the other. Trout overwintered in beaver ponds in large (N = 80–120), mixed aggregations. In both streams, both species decreased use of submerged cover following the formation of surface ice. Our results indicate that (1) continued activity by trout during winter is common in streams with dynamic ice conditions and (2) complex mixes of habitat are needed to provide suitable fall and winter habitat for these species.

Sea-ice production and transport of pollutants in the Laptev Sea, 1979–1993

Pollutants such as radionuclides can be incorporated into ice formed in shallow waters of the marginal seas, by suspension freezing, including frazil- and anchor-ice formation. This ice thickens through the winter and can survive the summer melt to eventually be pushed into the perennial ice zone and thus be transported long distances. After a few years, when the ice finally melts, these radionuclides can be re-released in biologically rich waters. We estimate that a mean of 256 000 km 2 of sea ice is produced annually in the shallow water area of the Laptev Sea during the October freeze-up and in the flaw lead during winter, accounting for approx. 20% of the total ice area fluxing through the Fram Strait per year.

Fall and Winter Movements of and Habitat Use by Cutthroat Trout in the Ram River, Alberta

Abstract Fall and winter movements of and habitat use by cutthroat trout Oncorhynchus clarki were studied with radiotelemetry in low, mid, and high altitudes of a river system to evaluate the timing and extent of habitat shifts when fish moved from summer feeding areas to overwintering areas. The movements of 20 fish were monitored from August to November 1991, and 17 fish were monitored from October to December 1992. Cutthroat trout moved out of summer habitats in mid-September, and many made a two-stage shift in habitat use from summer to winter that was associated with anchor ice formation. When cutthroat trout were excluded from fall habitats by anchor ice, they moved to overwintering areas less likely to be influenced by frazil and anchor ice: deep pools with ice cover or areas where water temperatures were higher than the rest of the stream because of springs or upwelling warm groundwater. Cutthroat trout used deeper water and smaller diameter substrates in winter than in summer but used less cover ...

Weight of the Evidence is the Right Approach

Sampling and field experiments were conducted from 1975 to 1990 to test how the structure of marine benthic communities around McMurdo Station, Antarctica varied with levels of anthropogenic contaminants in marine sediments. The structure of communities (e.g., infauna density, species composition, and life history characteristics) in contaminated and uncontaminated areas were compared with the structure of communities influenced by two large‐scale natural disturbances, anchor ice formation and uplift or iceberg scour. Benthic communities changed radically along a steep spatial gradient of anthropogenic hydrocarbon, metal, and PCB contamination around McMurdo Station. The heavily contaminated end of the gradient, Winter Quarters Bay, was low in infaunal and epifaunal abundance and was dominated by a few opportunistic species of polychaete worms, especially Capitella spp., Ophryotrocha claperedii, and Gyptis sp. These are relatively small and motile species. Closely related species live in organically enriched and anthropogenically disturbed sediments throughout temperate latitudes. The edge of the heavily contaminated bay, the transition area, contained several motile polychaete species with less opportunistic life histories, especially Tharyx sp. and Haploscoloplos kerguelensis. Uncontaminated sedimentary habitats harbored dense tube mats of infaunal animals numerically dominated by populations of polychaete worms, crustaceans, and a large suspension feeding bivalve. These species are generally large and relatively sessile, except for several crustacean species living among the tubes. Community patterns along the anthropogenic disturbance gradient were similar to community changes along a natural gradient of anchor ice disturbance. The same motile and opportunistic polychaete worms were most abundant where anchor ice freezing and uplift were most severe. The motile polychaetes, Tharyx sp., Haploscoloplos kerguelensis, and Polygordius sp., were abundant at the edge of the anchor ice disturbance zone. The undisturbed bottom harbored the same dense tube mat community and large bivalve population. Community changes along the anthropogenic disturbance gradient were also similar to colonization patterns into bottom areas gouged by icebergs. The most recent ice gouges along the east side of McMurdo Sound contained large numbers of the motile opportunistic polychaete worms. Ice gouges along the western sound contained more motile species of infauna compared to adjacent undisturbed bottoms with large numbers of tube‐dwelling infauna. Motile species were also the first to colonize experimental sediments placed on the sea floor for 6 yr. Although the community patterns around anthropogenic and natural disturbances were similar, particularly the motile and opportunistic species at heavily disturbed and marginal areas, the natural disturbances cover much greater areas of the sea floor around the entire Antarctic continent. On the other hand, recovery from chemical contamination is likely to take many more decades than recovery from natural disturbances as contaminant degradation is a slow process. This process can be enhanced by ongoing pollution abatement and cleanup operations.

Failure of Submersed Macrophytes to Provide Cover for Rainbow Trout throughout Their First Winter in the Henrys Fork of the Snake River, Idaho

Abstract Submersed aquatic plants that are abundant in some stream reaches have a potential to provide winter concealment cover for juvenile salmonids. We monitored an index of macrophyte abundance in a portion of the Henrys Fork of the Snake River during two winters that differed in severity and assessed the densities of age-0 rainbow trout Oncorhynchus mykiss associated with the macrophytes. The macrophyte index averaged 84–87%, in November 1989 and 1992, and an average of 10–13 fish/100 m2 were concealed there. In 1990, macrophyte cover declined to 59% in January and 46% in early February; fish density declined by about one-third by January and dropped to nearly zero in February. In 1992–1993, the macrophyte index declined to an average of 39% following anchor ice formation in December and to 32% in January. Fish density in December was reduced to about half of the November density and to about 1 fish/100 m2 in January. Movement of marked fish in 1989–1990 was predominantly from macrophytes into cobble...

Sediments in Arctic sea ice: Implications for entrainment, transport and release

Despite the Arctic sea ice cover's recognized sensitivity to environmental change, the role of sediment inclusions in lowering ice albedo and affecting ice ablation is poorly understood. Sea ice sediment inclusions were studied in the central Arctic Ocean during the Arctic 91 expedition and in the Laptev Sea (East Siberian Arctic Region Expedition 1992). Results from these investigations are here combined with previous studies performed in major areas of ice ablation and the southern central Arctic Ocean. This study documents the regional distribution and composition of particle-laden ice, investigates and evaluates processes by which sediment is incorporated into the ice cover, and identifies transport paths and probable depositional centers for the released sediment. In April 1992, sea ice in the Laptev Sea was relatively clean. The sediment occasionally observed was distributed diffusely over the entire ice column, forming turbid ice. Observations indicate that frazil and anchor ice formation occurring in a large coastal polynya provide a main mechanism for sediment entrainment. In the central Arctic Ocean sediments are concentrated in layers within or at the surface of ice floes due to melting and refreezing processes. The surface sediment accumulation in central Arctic multi-year sea ice exceeds by far the amounts observed in first-year ice from the Laptev Sea in April 1992. Sea ice sediments are generally fine grained, although coarse sediments and stones up to 5 cm in diameter are observed. Component analysis indicates that quartz and clay minerals are the main terrigenous sediment particles. The biogenous components, namely shells of pelecypods and benthic foraminiferal tests, point to a shallow, benthic, marine source area. Apparently, sediment inclusions were resuspended from shelf areas before and incorporated into the sea ice by suspension freezing. Clay mineralogy of ice-rafted sediments provides information on potential source areas. A smectite maximum in sea ice sediment samples repeatedly occurred between 81°N and 83°N along the Arctic 91 transect, indicating a rather stable and narrow smectite rich ice drift stream of the Transpolar Drift. The smectite concentrations are comparable to those found in both Laptev Sea shelf sediments and anchor ice sediments, pointing to this sea as a potential source area for sea ice sediments. In the central Arctic Ocean sea ice clay mineralogy is significantly different from deep-sea clay mineral distribution patterns. The contribution of sea ice sediments to the deep sea is apparently diluted by sedimentary material provided by other transport mechanisms.

Late Autumn Runoff and Sediment Transport in a Proglacial Drainage System, Sermilik, East Greenland

Hasholt, Bent: Late Autumn Runoff and Sediment Transport in a Proglacial Drainage System, Sermilik, East Greenland. Geografisk Tidsskrift 93:1–5. Copenhagen 1993. Field investigations of runoff and sediment transport were carried out in the proglacial area of the Mitdluagkat Glacier drainage basin in September 1992. Runoff in the proglacial stream was 32 l/s/km2. Runofffrom the northern flank of the glacier at the outlet of Lake Kugssuag was 14 l/s/km2. Mean daily sediment transport was 17 t/d in the proglacial valley and 0.2 t/d at the outlet of the lake. It was clearly demonstrated that the formation of frazil ice and anchor ice caused increased sediment transport, dominating the total load of the proglacial stream during the measuring period 2/9–19/9.

Reproduction of Antarctic Benthic Marine Invertebrates: Tempos, Modes, and Timing

Work on the life histories of common antarctic benthic marine invertebrates over the past several decades demands a revision of several widely held paradigms. First, contrary to expectations derived from work on temperate species, there is little or no evidence for temperature adaptation with respect to reproduction (gametogenesis), development, and growth. It remains to be determined whether the slow rates of these processes reflect some inherent inability to adapt to low temperatures, or are a response to features of the antarctic marine environment not directly related to low temperature, such as low food resources. Secondly, contrary to the widely accepted opinion designated as “Thorson's rule,” pelagic development is common in many groups of shallow-water marine invertebrates. In fact in some groups, such as asteroids,pelagic development is as prevalent in McMurdo Sound, the southern-most open-water marine environment in the world, as in central California. In other taxonomic groups, especially gastropods, there does seem to be a genuine trend toward non-pelagic development from tropical to antarctic latitudes. Although this trend has been predicted by theoretical models, its underlying causes appear to be group specific rather than general. Thirdly, pelagic lecithotrophic development, often considered to be of negligible importance, occurs in many shallow-water antarctic marine macroinvertebrates. Pelagic lecithotrophy may be an adaptation to a combination of poor food conditions in antarctic waters most of the year and slow rates of development. Nevertheless, some of the most abundant and widespread antarctic marine invertebrates have pelagic planktotrophic larvae that take very long times to complete development to metamorphosis. These species areparticularly prevalent in productive regions of shallow water (<30 m), which are frequently disturbed by anchor ice formation, and the production of numerous pelagic planktotrophic larvaemay represent a strategy for colonization. Although planktotrophic larvae tend to be seasonal in occurrence, their production is not linked particularly closely to the mid-summer pulse of phytoplankton production. These larvae show no evidence of starvation, even during times when phytoplankton abundance is very low, and they may depend on unusual sources of food, such as bacteria. How they escape the selective conditions that apparently led to a predominance of non-feeding modes of development in antarctic marine invertebrates remains as a major challenge for antarctic marine biology.

Interdecadal Variation in an Antarctic Sponge and Its Predators from Oceanographic Climate Shifts

During the 1960s there was extensive formation of anchor ice to depths of 30 meters at McMurdo Station, Antarctica. During this period the sponge Homaxinella balfourensis was rare, as were its predators in that depth zone. Most of the existing sponges were killed by anchor ice. During the 1970s, anchor ice formation was reduced, and there was a massive recruitment of Homaxinella, which covered as much as 80 percent of the substrata in that zone. Many predators appeared but did not control the sponge population, and it continued to grow through that decade. The early 1980s were characterized by ice formation and almost all of the Homaxinella were eliminated, leaving an order of magnitude more predators in that zone. The interdecadal increases in anchor ice probably result from local upwelling of extremely cold deep water, possibly in response to shifts in the strengths of regional currents.

Winter Stream Conditions and Use of Habitat by Brook Trout in High-Elevation Wyoming Streams

Abstract Winter stream conditions at elevations between 2,280 and 3,205 m above mean sea level and the use of winter habitat by adult brook trout Salvelinus fontinalis above 2,990 m were evaluated in 1983–1984 and 1984–1985. Little surface ice was observed at elevations above 2,900 m, which was associated with high snow accumulation; moderate surface ice and anchor ice formation were observed at elevations from 2,550 to 2,900 m; extensive surface ice formation occurred at 2,550 m. Little snow accumulated at 2,550 m and surface ice physically excluded substantial brook trout habitat. In late fall, brook trout at elevations above 2,990 m tended to move into low-gradient areas where they remained active throughout the winter. During winter, brook trout appeared to select for areas with maximum velocities of 15 cm/s or less, measured during summer low flow, and for deeper water, but not for substrate type.

Frazil Ice Formation: A Review

The problems associated with frazil ice formation are examined, the current state-of-the-art is reviewed, and recommendations for future research are made. No priorities are assigned to these recommendations. Future research should focus on obtaining heat transfer data, temperature measurements, flow measurements, physical measurements on frazil ice crystals (particularly frazil ice concentration), frazil ice nucleation processes, evolution of frazil ice crystals, anchor ice formation, forecasting the occurence of frazil ice, entrainment of frazil ice crystals in the flow and the resulting two-phase flow, adherence of frazil ice crystals to each other and to objects in the flow, granular growth in pans, floe producing mechanisms in rivers, and the initiation and development of river ice covers from frazil ice. The greatest need is for field measurements and field investigations of the preceding problems during periods of frazil ice formation in rivers.

Anchor Ice Formation in McMurdo Sound, Antarctica, and Its Biological Effects

Aggregations of ice platelets accumulate below the annual sea ice (subice platelet layer) and on the bottom (anchor ice) to depths of 33 meters. Observations of ice platelets adhering to submerged lines support the conclusion that 33 meters is the lower limit for ice formation in the water column in this area. The rising anchor ice lifts epibenthic fauna and has a pronounced effect on the distribution of the epibenthic organisms.

Discussion of “The formation of frazil and anchor ice in cold water”

Any technical paper on the phenomena of anchor‐ and frazil‐ice formation is incomplete without a reference to, and discussion of, the research and reports in this field by Altberg, Byden [see Elges, 1940], and Devik [1949], and a reference to the exceptionally complete bibliography on underwater ice prepared by ELGES [1940]. This excellent bibliography contains 91 references to publications on underwater and anchor ice of which 16 are by Altberg and 16 by Bydin. It is probable that the report by ALTBERG [1936] constitutes one of the greatest contributions to be found in the literature on both fundamental and applied research in anchor‐ and frazil‐ice formation.Schaefer has reopened the question of anchor‐ice formation by long‐wave radiation loss from submerged objects. He, at least, implies that BARNES [1906] may have been right in attributing the formation of anchor ice on the stream bed to cooling by long‐wave radiational heat losses through the water. This implication, added to the definite statements by Parsons [1942] and by Linsley and Others [1949, p. 147] that anchor ice occurs only in streams with dark rock bottoms and never on cloudy nights or under bridges, has been thoroughly refuted by Altberg. It is rather astonishing to note that the major works of Barnes and Altberg are cited, side by side, in the refences on page 148 in Meinzer's “Hydrology,” but that credence is given in the text only to Barnes' theory which even at that time (1940) was in disrepute.

The formation of frazil and anchor ice in cold water

Observations are presented concerning the formation of frazil and anchor ice under natural conditions and several methods are described for studying their physical properties. Photomicrographs show that the stable form of frazil ice is a thin, free‐floating, rounded disk and that accumulations of these simple forms followed by regelation probably account for most of the underwater structures forming in bulk water super‐cooling to about −0.01°C. Frazil ice particles tend to gather on the upstream side of underwater objects with low adhesion between the collector and the ice mass.Anchor ice forms as thin crystalline sheets firmly attached to underwater objects. Those observed were unlike frazil ice in appearance and general characteristics. A method is described for inducing the formation of frazil ice on a large scale by seeding supercooled water with small fragments of solid CO2. Practical applications are suggested to determine whether this method may have economic importance wherever frazil ice causes trouble to hydroplants and similar installations in flowing streams which develop super‐cooling.