Otolith oxygen and carbon stable isotopes in wild and laboratory-reared plaice (Pleuronectes platessa)

The relationship between water temperature, growth rate, and otolith isotopic ratios was measured for juvenile plaice (Pleuronectes platessa) reared at two temperatures (11 and 17°C) and two feeding regimes (1 and 3 prey items·ml^?1). The otolith isotope ratios in individual fish ranged from ?2 to ?4 for carbon isotope ratios (δ¹³C) and from 0.2 to 1.9 for oxygen isotope ratios (δ¹⁸O). The otolith oxygen isotope ratios were significantly affected by water temperature, but not by feeding level, and there were no significant synergistic effects. The fractionation of oxygen isotopes during otolith growth was independent of individual growth rate. Carbon isotope ratios were not significantly affected by food ration or water temperature, but were related to fish growth rate. The carbon isotope ratios were negatively correlated with fish length in the colder water treatments, and tended to increase with fish length in the warm water treatments. The laboratory-determined relationship between otolith oxygen isotope ratio and water temperature was applied to individuals of five species (plaice, cod, whiting, haddock, gurnard) collected in a single trawl sample. The otolith derived temperatures often overestimated measured water temperatures. The difference between real and estimated water temperatures varied between species, and the closest fit was for field-caught plaice.     

Long-term trends in water temperature and ice cover in the subalpine lake, Øvre Heimdalsvatn,and nearby lakes and rivers

Long-term data series of ice cover on lakes and river temperatures from the mountain areas of Norway are lacking. The present study analyses the last four decades of ice data from the subalpine lake, Øvre Heimdalsvatn, and water temperature data from its outlet river, Hinøgla. These data are compared to water temperature data from three neighbouring, quite different locations, the glacier-fed rivers Leirungsåi and Sjoa, and the alpine lake, Bessvatn. The study also examines the air temperature/river temperature relationships, and the air temperature/ice freeze-up and break-up dates. During the months of July, August and September, the water temperature in Hinøgla was well correlated to the air temperature, but the correlation was poor in the remaining months due to the ice cover and snow conditions. A significant temperature increase of 2–3°C has been observed in Hinøgla in the months August–October since 1984. There were only minor changes in the duration of the ice cover season during the last 40 years, but a delay of 9 days was found in the freeze-up date and a delay of 6 days in the break-up date, although the latter was not significant.     

Winter movements and habitat use of riverine brown trout, white sucker and common carp in relation to flooding and ice break-up

Movement of radio-tagged riverine brown trout Salmo trutta , white sucker Catostomus commersoni and common carp Cyprinus carpio in the Grand River, Ontario, was minimal during the winter except during periods of high water discharge or the break-up of river ice. Ice break-up and flooding occur when southern air masses penetrate northwards in winter and as air temperatures increase in spring. Both white suckers and common carp moved the longest distances, generally in a downstream direction, during flooding and ice break-up. Brown trout moved less during these times. All three species had positive relationships between distance moved and water discharge. During periods of high water discharge and ice break-up, white suckers and common carp used backwater habitats more and main channel habitats less than during periods of low water discharge. During high flows, brown trout tended to use runs more and pools less. The break-up of river ice and accompanying flooding resulted in several fish being stranded on the floodplain. Backwater habitats appear to be important areas of refuge for riverine fishes during periods of flooding and ice break-up.     

气候变化对鄱阳湖白鹤越冬种群数量变化的影响

分析了1983—2011年鄱阳湖国家级自然保护区越冬白鹤种群数量的年际变化趋势,检验了白鹤种群动态与繁殖地和越冬地气候变化的相关性,气候变量包括月平均气温、月平均最高气温、月平均最低气温和月降水量。研究结果表明,鄱阳湖国家级自然保护区内的白鹤年最大数量平均为(2 130±153)只,呈显著地线性增长趋势(R2=0.454,F=22.441,df=28,P=0.000),但年际波动较大。在越冬地,越冬当年10月、11月、12月的气候变量与白鹤种群数量没有显著的相关性,但越冬初期10月份和越冬后期翌年3月份的气温变量与第4年、第5年、第6年及第7年的白鹤种群数量存在显著的正相关,表明越冬地气候对白鹤种群大小的影响存在时滞效应。越冬初期和末期可能是白鹤补充能量的关键阶段,而且越冬初期的气候可能也与冬季食物的数量或质量相关,因此这两个阶段的适宜气温可能有利于个体尤其是幼鹤的存活,使更多的个体参加繁殖,由于白鹤的性成熟年龄在3—5a,因此其对白鹤种群增长的有利影响会在3a以后表现出来。白鹤种群数量变化与繁殖地繁殖期的降水量没有显著的相关性,而与7月份的气温变量存在显著的正相关。多元线性回归分析结果表明,6a前的10月份平均最低温度、2a前的10月最高温度及5a前的10月平均气温是白鹤种群数量变化的显著预测因子,共同解释了鄱阳湖国家级自然保护区白鹤种群数量变化的74.8%(F=23.807,df=27,P=0.000)。     

Increasingly ice-free winters and their effects on water quality in Sweden’s largest lakes

Mean global air temperatures have steadily increased during recent decades, resulting in an earlier timing of lake ice breakup. In Sweden’s largest lakes, Vänern and Vättern, the breakup of ice has occurred considerably earlier since 1979 and ice-free winters have become more frequent. Comparison between the years when the lakes were ice covered with those when they remained ice-free in terms of 37 lake variables revealed significant differences in water temperatures, sulphate concentrations and the biomass of diatoms in May after ice breakup (P < 0.01). In particular, the biomass of the genus Aulacoseira increased significantly, which may explain increasing complaints about algae that clog fishing-nets, filter-beds and micro-strainers in waterworks in Vänern and Vättern. We assume that Aulacoseira is mainly affected by changes in climate-driven water circulation patterns. In contrast, other observed water quality changes such as changes in sulphate concentration might rather be attributed to changes in atmospheric deposition. To explain water quality changes in Sweden’s largest lakes it is important to consider changes in both climate and atmospheric deposition as well as catchment measures.     

Responses of Zooplankton Populations to Four Decades of Climate Warming in Lakes of Southwestern Alaska

Zooplankton support a variety of important ecosystem processes in lakes but our understanding of how these organisms respond to ongoing climate change is superficial. Aquatic ecosystems have been exposed to substantial climate warming in the last century, and this trend is certain to continue, especially in northern latitudes. We analyzed a long time series of a variety of physical attributes of Lake Aleknagik, southwest Alaska, to quantify warming trends between 1963 and 2009, and to assess zooplankton community responses to variation in thermal conditions. Our analyses demonstrate clear trends toward earlier spring ice break-up, increases in average epilimnetic temperatures and an 18.5% increase in summer epilimnetic degree days since 1963. We estimated the magnitude and direction of changes in zooplankton production and end of season densities in response to changes in thermal environment, then explored whether the climate-driven responses in production are common in five large lakes that are distributed across a coastal-interior landscape gradient. Although we detected no clear directional changes in zooplankton densities or production rates, there were clear correlations between these variables and interannual variation in thermal conditions. The positive effects of earlier spring ice break-up and increase in summer degree days were strongest on the production and density responses of Daphnia and Bosmina, and the lagged effect of temperature was important and negative only for calanoid copepods. There was a negative effect of sockeye escapement to Lake Aleknagik in the previous year on all taxa. There were lake-specific effects of changes in the thermal environment on almost all taxa and small gradients in the magnitude of responses across the landscape, but no systematic patterns of landscape control.     

Impacts of drought and predicted effects of climate change on fish growth in temperate Australian lakes

Climate change is expected to negatively impact many freshwater environments due to reductions in stream‐flow and increases in temperature. These conditions, however, can already be found today in areas experiencing significant drought; current observations of species' responses to droughts can be used to make predictions about their future responses to climate change. Using otolith analysis, we recreated golden perch (Macquaria ambigua) growth chronologies from two temperate lake populations in southeastern Australia over a 15‐year period pre‐ and during a supraseasonal drought. We related interannual growth variation to landscape‐scale changes in temperature and hydrological regimes: fish growth declined as water levels in the lakes dropped during the drought, but this effect was offset by increased growth in warmer years. We hypothesize that golden perch are responding to fluctuations in food availability and intraspecific competition related to water level and to an optimization of physiological growth conditions related to increases in growing season length. Based on our analyses, we made predictions of future growth under a number of climate change scenarios that incorporate forecast deviations in stream‐flows and air temperature. Despite climatic models predicting significant declines in future water availability, fish growth may increase due to a disproportionate lengthening of the growing season. As the two lakes are at the limit of the southerly range of golden perch, our results are consistent with previous findings of climate‐change driven latitudinal range shifts in a poleward direction. We discuss assumptions concerning the constancy of ecological interactions into the future that warrant further study. Our research provides a novel application of biochronological analysis that could be used elsewhere to further our knowledge of species responses to changing environments.     

越冬地气候条件对鄱阳湖自然保护区白琵鹭种群数量的影响

分析了1985—2011年鄱阳湖国家级自然保护区白琵鹭(Platalea leucorodia)越冬种群数量的年际变化趋势,检验了白琵鹭种群年际数量变化与越冬地气候变化的相关性,气候变量包括月平均气温、月平均最高气温、月平均最低气温和月降水量。研究结果表明,1985—2011年鄱阳湖国家级自然保护区白琵鹭种群数量为(4 632±470)只,呈显著的线性增长趋势,但年际波动较大。在越冬地,白琵鹭的种群数量与白琵鹭越冬期当年冬季各月的气温和降水变量相关系数较小,且均没有显著的相关性。同时,发现越冬地的气候条件对白琵鹭种群数量的影响存在显著的时滞效应:越冬期的月值气候变量与1—9a后的白琵鹭种群数量几乎都存在显著正相关性;10月降水量与2a后的白琵鹭种群数量存在显著负相关,12月平均最高气温与8a后的白琵鹭种群数量存在显著负相关。多元线性回归分析结果表明,越冬地2a前的10月平均最高气温、4a前的11月平均最高气温、8a前的11月降水量、4a前的12月平均气温是白琵鹭种群数量变化的显著预测变量,共同解释了白琵鹭种群数量年际变化的78.9%;其中前3个变量可以共同解释白琵鹭种群数量变化的72.1%,这两个月份正是白琵鹭的越冬初期,是结束长距离迁徙的阶段,可能是白琵鹭补充能量的关键时期,这个时期越冬地恶劣的天气可能导致白琵鹭无法获得充足的能量,不利于能量的恢复,从而可能给种群造成不利的影响。     

Size variability of juvenile Atlantic salmon: links to environmental conditions

Climate change models predict a 2 to 6° C increase in air temperature within the next 100 years in the Maritime Provinces of eastern Canada. Higher air temperatures are expected to contribute to increased water temperatures, alterations in stream flow conditions, and ultimately reductions in fish growth. Mean annual size-at-age of juvenile Atlantic salmon Salmo salar decreased in the Northwest Miramichi and Southwest Miramichi Rivers between 1971–1999. Lengths-at-age of juveniles were significantly correlated between the two rivers. For Atlantic salmon parr, stronger associations between inter-cohort fork length ( L _F) than intra-cohort L _F were observed, suggesting that environmental conditions in the current year of growth have the more significant effects on size of age 2 year parr than conditions encountered the previous year by age 1 year parr of the same cohort. Fork lengths of parr were significantly and negatively associated with spring air and water temperatures. In the Miramichi River, increases in air and water temperature as predicted from climate change models may adversely affect growth of juvenile Atlantic salmon parr, reducing the overall productivity of the Atlantic salmon populations in this region.     

Intertidal community composition along rocky shores in South-west Greenland: a quantitative approach

The intertidal communities on rocky shores are directly subjected to climatic changes in air and water temperatures and to derived effects of climate change, such as changes in freshwater run-off and ice dynamics. Global warming occurs at elevated rates in Greenland and results in changing species distributions with range expansions to the north and new species entering terrestrial habitats from the south. There is, however, no quantitative knowledge of past or present species distribution in the littoral zone of Southern Greenland, an area which represents an important gateway for northern range expansions of temperate species. This study provides baseline information on abundances of macroorganisms in the eulittoral Southern Greenland. This knowledge will pave the way for future studies on the impact of climate change and anthropogenic activities on these communities. Nine sites, situated at different exposure levels, were investigated. A total of 22 taxa were recorded, suggesting low species richness. Patellid limpets and predators such as dogwhelks, starfish and crabs were absent. Total standing stock ranged from 0 to 31,898 g m^?2. Species composition and biomasses were related to locally generated wave exposure, oceanic swells and ice scouring. The high standing stock at sheltered sites indicated that neither light, temperature nor nutrients, constrained buildup of biomass in this environment. Inshore seasonal measurements of water and air temperatures were recorded for the first time in the region, displaying low water temperatures and high variation in air temperatures, indicating lack of insulating stable sea ice in the area. Possible impacts of ongoing temperature changes are discussed based on recorded temperatures and meteorological data from the past 30 years.     

Climatic responses of Pinus pseudostrobus and Abies religiosa in the Monarch Butterfly Biosphere Reserve,Central Mexico

Understanding the effects of climate on the growth of trees is important to project the response of forests to climate change. Dendrochronological analysis offers a “proxy” source for the effects of climatic variation on tree growth at different spatial and temporal scales. To examine influences of temperature and precipitation on radial growth of Pinus pseudostrobus and Abies religiosa, this study combines measurements of radial growth patterns of forest trees in the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico with temperature and precipitation variables from instrumental records. Dendrochronological samples were collected as cross sections and increment cores by using a chainsaw and increment borers, respectively. Total ring-width chronologies were developed for each site. Principal component analyses (PCA) were used to identify common temperature, precipitation and tree growth variation patterns. Correlation and response function analyses between chronologies and records of temperature and precipitation were used to evaluate the relation of climate variables on tree growth. The months during which tree growth was most strongly affected by precipitation were January, February and October from the previous year; only the temperature of September from the previous year affected the tree growth. In some chronologies, May’s average monthly maximum temperature was negatively correlated with tree growth. PCA and a comparison of PCA factor scores of climatic variables and chronologies showed no significant differences between northern, central or southern portions of the MBBR. Apparently, tree growth in the MBBR is reduced in years of low January–May precipitation combined with high summer (September of the previous year) temperatures, a scenario which is likely to occur as a consequence of global climate change.     

Leaf growth dynamics in four plant species of the Patagonian Monte, Argentina

Studying plant responses to environmental variables is an elemental key to understand the functioning of arid ecosystems. We selected four dominant species of the two main life forms. The species selected were two evergreen shrubs: Larrea divaricata and Chuquiraga avellanedae and two perennial grasses: Nassella tenuis and Pappostipa speciosa. We registered leaf/shoot growth, leaf production and environmental variables (precipitation, air temperature, and volumetric soil water content at two depths) during summer-autumn and winter-spring periods. Multiple regressions were used to test the predictive power of the environmental variables. During the summer-autumn period, the strongest predictors of leaf/shoot growth and leaf production were the soil water content of the upper layer and air temperature while during the winter-spring period, the strongest predictor was air temperature. In conclusion, we found that the leaf/shoot growth and leaf production were associated with current environmental conditions, specially to soil water content and air temperature.     

Variation in Serripes groenlandicus (Bivalvia) growth in a Norwegian high-Arctic fjord: evidence for local- and large-scale climatic forcing

We examined the growth rate of the circumpolar Greenland Cockle ( Serripes groenlandicus ) over a period of 20 years (1983–2002) from Rijpfjord, a high-Arctic fjord in northeast Svalbard (80°10'N, 22°15'E). This period encompassed different phases of large-scale climatic oscillations with accompanying variations in local physical variables (temperature, atmospheric pressure, precipitation, sea ice cover), allowing us to analyze the linkage between growth rate, climatic oscillations, and their local physical and biological manifestations. Standard growth index (SGI), an ontogenetically adjusted measure of annual growth, ranged from a low of 0.27 in 2002 up to 2.46 in 1996. Interannual variation in growth corresponded to the Arctic climate regime index (ACRI), with high growth rates during the positive ACRI phase characterized by cyclonic ocean circulation and a warmer and wetter climate. Growth rates were influenced by local manifestations of the ACRI: positively correlated with precipitation and to a lesser extent negatively correlated with atmospheric pressure. A multiple regression model explains 65% of the variability in growth rate by the ACRI and precipitation at the nearest meteorological station. There were, however, complexities in the relationship between growth and physical variables, including an apparent 1 year lag between physical forcing changes and biological response. Also, when the last 4 years of poor growth are excluded, there is a very strong negative correlation with ice cover on a pan-arctic scale. Our results suggest that bivalves, as sentinels of climate change on multi-decadal scales, are sensitive to environmental variations associated with large-scale changes in climate, but that the effects will be determined by changes in environmental parameters regulating marine production and food availability on a local scale.     

Phenotypic/genotypic sex mismatches and temperature‐dependent sex determination in a wild population of an Old World atherinid,the cobaltcap silverside Hypoatherina tsurugae

Several New World atheriniforms have been recognized as temperature‐dependent sex determined (TSD) and yet possess a genotypic sex determinant (amhy) which is primarily functional at mid‐range temperatures. In contrast, little is known about the sex determination in Old World atheriniforms, even though such knowledge is crucial to understand the evolution of sex determination mechanisms in fishes and to model the effects of global warming and climate change on their populations. This study examined the effects of water temperature on sex determination of an Old World atheriniform, the cobaltcap silverside Hypoatherina tsurugae, in which we recently described an amhy homologue. We first assessed the occurrence of phenotypic/genotypic sex mismatches in wild specimens from Tokyo Bay for three years (2014–2016) and used otolith analysis to estimate their birth dates and approximate thermal history during the presumptive period of sex determination. Phenotypic sex ratios became progressively biased towards males (47.3%–78.2%) during the period and were associated with year‐to‐year increases in the frequency of XX‐males (7.3%–52.0%) and decreases in XY/YY‐females (14.5%–0%). The breeding season had similar length but was delayed by about 1 month per year between 2014 and 2016, causing larvae to experience higher temperatures during the period of sex determination from year to year. Larval rearing experiments confirmed increased likelihood of feminization and masculinization at low and high temperatures, respectively. The results suggest that cobaltcap silverside has TSD, or more specifically the coexistence of genotypic and environmental sex determinants, and that it affects sex ratios in wild populations.     

Effects of temperature,starvation and photoperiod on otolith increments in larval Chinese sucker, <Emphasis Type="Italic">Myxocyprinus asiaticus</Emphasis>

Effects of water temperature, starvation and photoperiod on otolith increment formation in larval Chinese sucker, Myxocyprinus asiaticus, were examined in this study. The results demonstrated that otolith increments of larvae reared under diel temperature fluctuations were very clear and appeared with a high contrast, while those of larvae raised under constant water temperatures were vague or hard to identify. The increment deposition rates were less than 1.0/day in later stage of starvation period. Also, increment deposition was affected by cyclic regimes of water temperature fluctuations, the number of increments corresponded to the cycle times rather than the exact days larvae experienced. However, varying of feeding frequency and photoperiod did not result in any alterations of daily increment formation. Increment width increased obviously with higher rearing temperatures till several days after yolk absorption. However, the width presented an ontogenetic decline during period of endogenous nutrition and the first several days of exogenous nutrition stage. Starvation decoupled the relationship between somatic growth and otolith growth; otolith kept growing, and increment width of starved larvae was similar to those in fed individuals before 9–20 days old; the divergence of increment width from the fed larvae occurred in later stage of starvation period. It can be concluded that temperature regimes and food levels are the major factors affecting increment formation in terms of clarity, deposition rate and width, while photoperiod and feeding frequency have less influence on it.     

Die küstenvegetation ostkanadas: D. Thannheiser. Münstersche Geographische Arbeiten. No. 10. Schöningh,Paderborn, 1981, 201 pp. 166 figs., 41 tables,DM. 41.50. ISBN 3-506-73210-2

Temperatures 10 and 2 cm above water level, in leaves of Salvinia molesta Mitchell, and 2 and 10 cm below water level, were measured in the field at hourly intervals over a total of 125 days. Temperature cycles of leaves and air had mean diurnal amplitudes of 8°C in summer and 17°C in winter; cycles in water lagged behind and had amplitudes which decreased with depth. Most parts of S. molesta were warmer than the air at a nearby weather station most of the time and there was temperature stratification in the water during the warm part of each day.Standard meteorological variables were selected, using stepwise regression, to predict daily maximum and minimum temperatures of S. molesta. Thermal inertia of water in the lake seemed to elevate S. molesta temperatures in autumn and depress them in spring compared with temperatures at the weather station. Better predictors were obtained by adding to meteorological variables a function based on the annual cycle of temperatures 10 cm below water level. Hourly temperatures experienced by S. molesta were predicted using curves fitted to diurnal cycles. The reliability of predictions was tested for each season of the year with independent data for a total of 78 days. Predicted temperatures were close to observed temperatures both in absolute terms and in terms of temperature-dependent growth rates of S. molesta.     

Winter warming as an important co‐driver for Betula nana growth in western Greenland during the past century

Growing season conditions are widely recognized as the main driver for tundra shrub radial growth, but the effects of winter warming and snow remain an open question. Here, we present a more than 100 years long Betula nana ring‐width chronology from Disko Island in western Greenland that demonstrates a highly significant and positive growth response to both summer and winter air temperatures during the past century. The importance of winter temperatures for Betula nana growth is especially pronounced during the periods from 1910–1930 to 1990–2011 that were dominated by significant winter warming. To explain the strong winter importance on growth, we assessed the importance of different environmental factors using site‐specific measurements from 1991 to 2011 of soil temperatures, sea ice coverage, precipitation and snow depths. The results show a strong positive growth response to the amount of thawing and growing degree‐days as well as to winter and spring soil temperatures. In addition to these direct effects, a strong negative growth response to sea ice extent was identified, indicating a possible link between local sea ice conditions, local climate variations and Betula nana growth rates. Data also reveal a clear shift within the last 20 years from a period with thick snow depths (1991–1996) and a positive effect on Betula nana radial growth, to a period (1997–2011) with generally very shallow snow depths and no significant growth response towards snow. During this period, winter and spring soil temperatures have increased significantly suggesting that the most recent increase in Betula nana radial growth is primarily triggered by warmer winter and spring air temperatures causing earlier snowmelt that allows the soils to drain and warm quicker. The presented results may help to explain the recently observed ‘greening of the Arctic’ which may further accelerate in future years due to both direct and indirect effects of winter warming.     

Water availability is the main climate driver of neotropical tree growth

? Climate models for the coming century predict rainfall reduction in the Amazonian region, including change in water availability for tropical rainforests. Here, we test the extent to which climate variables related to water regime, temperature and irradiance shape the growth trajectories of neotropical trees. ? We developed a diameter growth model explicitly designed to work with asynchronous climate and growth data. Growth trajectories of 205 individual trees from 54 neotropical species censused every 2 months over a 4-year period were used to rank 9 climate variables and find the best predictive model. ? About 9% of the individual variation in tree growth was imputable to the seasonal variation of climate. Relative extractable water was the main predictor and alone explained more than 60% of the climate effect on tree growth, i.e. 5.4% of the individual variation in tree growth. Furthermore, the global annual tree growth was more dependent on the diameter increment at the onset of the rain season than on the duration of dry season. ? The best predictive model included 3 climate variables: relative extractable water, minimum temperature and irradiance. The root mean squared error of prediction (0.035 mm x d(-1)) was slightly above the mean value of the growth (0.026 mm x d(-1)). ? Amongst climate variables, we highlight the predominant role of water availability in determining seasonal variation in tree growth of neotropical forest trees and the need to include these relationships in forest simulators to test, in silico, the impact of different climate scenarios on the future dynamics of the rainforest.     

Do warmer winters change variability patterns of physical and chemical lake conditions in Sweden?

In this study, the effect of a warmer winter climate on variability patterns of physical and chemical lake conditions was examined by using monthly air temperature data from 72 meteorological Swedish sites, ice breakup data from 77 Swedish lakes and monthly data of 17 water chemical variables from 11 nutrient-poor Swedish reference lakes during 1988–2005. The results showed significantly increasing variations of lake ice breakup dates and nitrate concentrations over Sweden along with increasing winter air temperatures. Variability patterns of other water chemical variables were not affected by warmer winters. Nitrate concentrations increased their variability in spring and early summer not only between lakes but also within lakes, which was attributed to a climate-induced increase in spring nitrate concentrations in particular in southern Sweden, while summer nitrate concentrations remained rather constant and low all over Sweden (median 10 μg l⁻¹). Since nitrate concentrations play an important role for primary production, highly varying concentrations will be a challenge for biota to adapt.     

Antifreeze protein produced endogenously in winter rye leaves

After cold acclimation, winter rye (Secale cereale L.) is able to withstand the formation of extracellular ice at freezing temperatures. We now show, for the first time, that cold-acclimated winter rye plants contain endogenously produced antifreeze protein. The protein was extracted from the apoplast of winter rye leaves, where ice forms during freezing. After partial purification, the protein was identified as antifreeze protein because it modified the normal growth pattern of ice crystals and depressed the freezing temperature of water noncolligatively.