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1.
Effects of climate change and UV radiation on fisheries for arctic freshwater and anadromous species
Reist JD Wrona FJ Prowse TD Dempson JB Power M Köck G Carmichael TJ Sawatzky CD Lehtonen H Tallman RF 《Ambio》2006,35(7):402-410
Fisheries for arctic freshwater and diadromous fish species contribute significantly to northern economies. Climate change, and to a lesser extent increased ultraviolet radiation, effects in freshwaters will have profound effects on fisheries from three perspectives: quantity of fish available, quality of fish available, and success of the fishers. Accordingly, substantive adaptation will very likely be required to conduct fisheries sustainably in the future as these effects take hold. A shift to flexible and rapidly responsive 'adaptive management' of commercial fisheries will be necessary; local land- and resource-use patterns for subsistence fisheries will change; and, the nature, management and place for many recreational fisheries will change. Overall, given the complexity and uncertainty associated with climate change and related effects on arctic freshwaters and their biota, a much more conservative approach to all aspects of fishery management will be required to ensure ecosystems and key fished species retain sufficient resiliency and capacity to meet future changes. 相似文献
2.
Climate change is likely to act as a multiple stressor, leading to cumulative and/or synergistic impacts on aquatic systems. Projected increases in temperature and corresponding alterations in precipitation regimes will enhance contaminant influxes to aquatic systems, and independently increase the susceptibility of aquatic organisms to contaminant exposure and effects. The consequences for the biota will in most cases be additive (cumulative) and multiplicative (synergistic). The overall result will be higher contaminant loads and biomagnification in aquatic ecosystems. Changes in stratospheric ozone and corresponding ultraviolet radiation regimes are also expected to produce cumulative and/or synergistic effects on aquatic ecosystem structure and function. Reduced ice cover is likely to have a much greater effect on underwater UV radiation exposure than the projected levels of stratospheric ozone depletion. A major increase in UV radiation levels will cause enhanced damage to organisms (biomolecular, cellular, and physiological damage, and alterations in species composition). Allocations of energy and resources by aquatic biota to UV radiation protection will increase, probably decreasing trophic-level productivity. Elemental fluxes will increase via photochemical pathways. 相似文献
3.
For marine invertebrates, larval developmental mode is inseparably linked to the nutritional content of the egg. Within the
asterinid family of sea stars there have been multiple, independent, evolutionary transitions to lecithotrophic development
from the ancestral, planktotrophic state. To investigate the evolution of maternal investment and development within the Asterinidae,
we quantified individual lipid classes and total protein for eggs and larval stages of closely related species representing
three developmental modes (planktotrophy, planktonic lecithotrophy and benthic lecithotrophy). Within species, maternal provisioning
differed between females indicating that egg quality varied with parentage. Maternal investment was related to egg size but,
after correcting for egg volume, we identified two major oogenic modifications associated with the evolution of lecithotrophic
development: (1) a reduction in protein deposition that probably reflects the reduced structural requirements of nonfeeding
larvae, (2) an increase in deposition of a single class of energetic lipid, triglyceride (TG). The exception was Parvulastra exigua, which has benthic, lecithotrophic development and lays eggs with a lipid to protein ratio close to that of planktotrophs.
This oogenic strategy may provide P. exigua larvae with a protein “weight-belt” that assists in maintaining a benthic existence. Asterinids with planktotrophic development
used a significant portion of egg TG to build a feeding bipinnaria larva. For Meridiastra mortenseni, female-specific differences in egg TG were still evident at the bipinnaria stage indicating that egg quality has flow-on
effects for larval fitness. In lecithotrophic asterinids, TG reserves were not depleted in development to the larval stage
whereas protein stores may help fuel early larval development. Available data indicate that there may be two evolutionarily
stable egg lipid profiles for free-spawning, temperate echinoderms. 相似文献
4.
Large variations exist in the size, abundance and biota of the two principal categories of freshwater ecosystems, lotic (flowing water; e.g., rivers, streams, deltas and estuaries) and lentic (standing water; lakes, ponds and wetlands) found across the circumpolar Arctic. Arctic climate, many components of which exhibit strong variations along latitudinal gradients, directly affects a range of physical, chemical and biological processes in these aquatic systems. Furthermore, arctic climate creates additional indirect ecological effects through the control of terrestrial hydrologic systems and processes, particularly those associated with cryospheric components such as permafrost, freshwater ice and snow accumulation/ablation. The ecological structure and function of arctic freshwater systems are also controlled by external processes and conditions, particularly those in the headwaters of the major arctic rivers and in the adjacent marine environment. The movement of physical, chemical and biotic components through the interlinked lentic and lotic freshwater systems are major determinants of arctic freshwater ecology. 相似文献
5.
Various types of ecosystem-based climate proxies have been used to assess past arctic change. Although lotic records are relatively poor because of the constant reworking of riverine material, high-quality lentic data have been assembled back to the end of the Pleistocene and deglaciation of the circumpolar Arctic. In general, climatic variations in the Holocene, partly due to changes in the shrinking effect of glacier coverage, produced significant temporal and spatial variations in arctic hydrology and freshwater ecosystems. Of particular note were the vast expansions of northern peatlands during major protracted periods of wetting. More recent lake biota and sedimentiological data reflect the general warming trend that has occurred over the last one to two centuries and indicate major changes to freshwater characteristics such as ice-cover duration and thermal stratification. Such data provide an excellent baseline against which future effects of climate change can be both projected and measured. 相似文献
6.
M. Byrne T. A. A. Prowse M. A. Sewell S. Dworjanyn J. E. Williamson D. Vaïtilingon 《Marine Biology》2008,155(5):473-482
Lipid and protein biochemistry of eggs (84 μm in diameter), embryos and early larvae of the tropical echinoid Tripneustes gratilla (Linnaeus 1758) were quantified to determine how maternal provisions are used to fuel development of the echinopluteus. The
eggs contained a mean of 30.82 ng lipid and 87.32 ng protein. Energetic lipids were the major lipid component (55.52% of total
lipid) with the major class being triglyceride (TG: mean 15.9 ng, 51.58% of total). Structural lipid was dominated by phospholipid
(PL: mean 11.18 ng, 36.26% of total). Early embryogenesis was not a major drain on egg energetic lipid and protein. Development
of the functional feeding larva used ca. 50% of initial egg energetic lipid and most of this was TG. Maternal TG was still
present in the 8-day echinoplutei and it was estimated that this energetic lipid would be depleted in unfed larvae by day
10. There was no change in PL. In a separate experiment lipid biochemistry of rudiment stage larvae and early developing juveniles
were quantified to determine how lipids are used during metamorphosis. Fed larvae accumulated lipid (mean 275.49 ng) with
TG and PL being the major energetic and structural lipids, respectively. Larval lipid stores were not appreciably depleted
by metamorphosis and so were available for the early benthic stage juvenile. Juveniles started their benthic existence with
314 ng total lipid (TG: mean 46.84 ng, 14.9% of total, PL: mean 137.51 ng, 43.67% of total). Nile Red histochemistry and histology
showed that the stomach serves as a nutrient storage organ and, that lipid stores accrued by larvae sustain developing juveniles
for up to 4 days post settlement. Triglyceride supported both non-feeding stages of development and the prefeeding larval
and perimetamorphic benthic stage. In this first study of lipid stores in settlement stage echinoderm larvae, we show that
T. gratilla larvae sequester the same major energetic lipid (TG) to support the early juvenile that the female parent provided them to
fuel early development. 相似文献
7.
Seeking knowledge of traditional Indigenous burning practices to inform regional bushfire management
ABSTRACTA transdisciplinary review of the current academic knowledge of Indigenous traditional fire management is presented for the Mt Lofty Ranges in South Australia. For a long time, the roles of Indigenous management of the landscape have either been overlooked or discounted within environmental studies. That situation is beginning to change in many parts of Australia. However, this review of knowledge of traditional Indigenous burning practices specifically for the Mt Lofty Ranges suggests that there is very little formalised, academic knowledge available that could be utilised to inform prescribed burning practices in the region. Perhaps Indigenous peoples’ use of fire was strongly governed by individual choices, or perhaps established regimes demarcated roles across groups; perhaps some areas were burnt regularly and others were left unaltered – there is still no clear evidence from the academic literature to provide even limited understandings of such elements of pre-colonial fire regimes. That gap in knowledge will become increasingly problematic as the need for appropriate, sophisticated burning practices to respond to risk in peri-urban Adelaide increases with a changing climate. To learn from traditional Indigenous land management: (a) formal knowledge needs to be generated on past regional burning practices; and (b) understanding needs to be developed as to whether past burning practices could lead to effective hazard management and biodiversity outcomes within contemporary landscapes. Such an integration of Indigenous knowledge for effective environmental management will only be possible if the injustices of past exclusions of the importance of Indigenous biocultural practices are recognised. 相似文献
8.
9.
In general, the arctic freshwater-terrestrial system will warm more rapidly than the global average, particularly during the autumn and winter season. The decline or loss of many cryospheric components and a shift from a nival to an increasingly pluvial system will produce numerous physical effects on freshwater ecosystems. Of particular note will be reductions in the dominance of the spring freshet and changes in the intensity of river-ice breakup. Increased evaporation/evapotranspiration due to longer ice-free seasons, higher air/water temperatures and greater transpiring vegetation along with increase infiltration because of permafrost thaw will decrease surface water levels and coverage. Loss of ice and permafrost, increased water temperatures and vegetation shifts will alter water chemistry, the general result being an increase in lotic and lentic productivity. Changes in ice and water flow/levels will lead to regime-specific increases and decreases in habitat availability/quality across the circumpolar Arctic. 相似文献
10.
Climate change is projected to cause significant alterations to aquatic biogeochemical processes, (including carbon dynamics), aquatic food web structure, dynamics and biodiversity, primary and secondary production; and, affect the range, distribution and habitat quality/quantity of aquatic mammals and waterfowl. Projected enhanced permafrost thawing is very likely to increase nutrient, sediment, and carbon loadings to aquatic systems, resulting in both positive and negative effects on freshwater chemistry. Nutrient and carbon enrichment will enhance nutrient cycling and productivity, and alter the generation and consumption of carbon-based trace gases. Consequently, the status of aquatic ecosystems as carbon sinks or sources is very likely to change. Climate change will also very likely affect the biodiversity of freshwater ecosystems across most of the Arctic. The magnitude, extent, and duration of the impacts and responses will be system- and location-dependent. Projected effects on aquatic mammals and waterfowl include altered migration routes and timing; a possible increase in the incidence of mortality and decreased growth and productivity from disease and/or parasites; and, probable changes in habitat suitability and timing of availability. 相似文献