scholarly journals Productivity and Change in Fish and Squid in the Southern Ocean

2021 ◽  
Vol 9 ◽  
Author(s):  
Jilda Alicia Caccavo ◽  
Henrik Christiansen ◽  
Andrew J. Constable ◽  
Laura Ghigliotti ◽  
Rowan Trebilco ◽  
...  
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
Life Histories ◽  
Ross Sea ◽  
Global Climate ◽  
Management Strategies ◽  
Antarctic Fish ◽  
Ecosystem Approach ◽  
Ecosystem Structure ◽  
Global Drivers

Southern Ocean ecosystems are globally important and vulnerable to global drivers of change, yet they remain challenging to study. Fish and squid make up a significant portion of the biomass within the Southern Ocean, filling key roles in food webs from forage to mid-trophic species and top predators. They comprise a diverse array of species uniquely adapted to the extreme habitats of the region. Adaptations such as antifreeze glycoproteins, lipid-retention, extended larval phases, delayed senescence, and energy-conserving life strategies equip Antarctic fish and squid to withstand the dark winters and yearlong subzero temperatures experienced in much of the Southern Ocean. In addition to krill exploitation, the comparatively high commercial value of Antarctic fish, particularly the lucrative toothfish, drives fisheries interests, which has included illegal fishing. Uncertainty about the population dynamics of target species and ecosystem structure and function more broadly has necessitated a precautionary, ecosystem approach to managing these stocks and enabling the recovery of depleted species. Fisheries currently remain the major local driver of change in Southern Ocean fish productivity, but global climate change presents an even greater challenge to assessing future changes. Parts of the Southern Ocean are experiencing ocean-warming, such as the West Antarctic Peninsula, while other areas, such as the Ross Sea shelf, have undergone cooling in recent years. These trends are expected to result in a redistribution of species based on their tolerances to different temperature regimes. Climate variability may impair the migratory response of these species to environmental change, while imposing increased pressures on recruitment. Fisheries and climate change, coupled with related local and global drivers such as pollution and sea ice change, have the potential to produce synergistic impacts that compound the risks to Antarctic fish and squid species. The uncertainty surrounding how different species will respond to these challenges, given their varying life histories, environmental dependencies, and resiliencies, necessitates regular assessment to inform conservation and management decisions. Urgent attention is needed to determine whether the current management strategies are suitably precautionary to achieve conservation objectives in light of the impending changes to the ecosystem.

scholarly journals Climate extremes, variability, and trade shape biogeographical patterns of alien species

2020 ◽  
Author(s):  
Xuan Liu ◽  
Jason R Rohr ◽  
Xianping Li ◽  
Teng Deng ◽  
Wenhao Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Alien Species ◽  
Native Species ◽  
Bilateral Trade ◽  
Climatic Factors ◽  
Global Climate ◽  
Management Strategies ◽  
Climate Extremes ◽  
Precipitation Seasonality ◽  
Unique Variation

Abstract Understanding how alien species assemble is crucial for predicting changes to community structure caused by biological invasions and for directing management strategies for alien species, but patterns and drivers of alien species assemblages remain poorly understood relative to native species. Climate has been suggested as a crucial filter of invasion-driven homogenization of biodiversity. However, it remains unclear which climatic factors drive the assemblage of alien species. Here, we compiled global data at both grid scale (2,653 native and 2,806 current grids with a resolution of 2° × 2°) and administrative scale (271 native and 297 current nations and sub-nations) on the distributions of 361 alien amphibians and reptiles (herpetofauna), the most threatened vertebrate group on the planet. We found that geographical distance, a proxy for natural dispersal barriers, was the dominant variable contributing to alien herpetofaunal assemblage in native ranges. In contrast, climatic factors explained more unique variation in alien herpetofaunal assemblage after than before invasions. This pattern was driven by extremely high temperatures and precipitation seasonality, 2 hallmarks of global climate change, and bilateral trade which can account for the alien assemblage after invasions. Our results indicated that human-assisted species introductions combined with climate change may accelerate the reorganization of global species distributions.

scholarly journals Environmental forcing and Southern Ocean marine predator populations: effects of climate change and variability

2007 ◽  
Vol 362 (1488) ◽  
pp. 2351-2365 ◽  
Author(s):  
P.N Trathan ◽  
J Forcada ◽  
E.J Murphy
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
Food Webs ◽  
Time Scales ◽  
Trophic Level ◽  
Global Ocean ◽  
Ecosystem Structure ◽  
Marine Predator ◽  
Enso Events ◽  
Biological Responses

The Southern Ocean is a major component within the global ocean and climate system and potentially the location where the most rapid climate change is most likely to happen, particularly in the high-latitude polar regions. In these regions, even small temperature changes can potentially lead to major environmental perturbations. Climate change is likely to be regional and may be expressed in various ways, including alterations to climate and weather patterns across a variety of time-scales that include changes to the long interdecadal background signals such as the development of the El Niño–Southern Oscillation (ENSO). Oscillating climate signals such as ENSO potentially provide a unique opportunity to explore how biological communities respond to change. This approach is based on the premise that biological responses to shorter-term sub-decadal climate variability signals are potentially the best predictor of biological responses over longer time-scales. Around the Southern Ocean, marine predator populations show periodicity in breeding performance and productivity, with relationships with the environment driven by physical forcing from the ENSO region in the Pacific. Wherever examined, these relationships are congruent with mid-trophic-level processes that are also correlated with environmental variability. The short-term changes to ecosystem structure and function observed during ENSO events herald potential long-term changes that may ensue following regional climate change. For example, in the South Atlantic, failure of Antarctic krill recruitment will inevitably foreshadow recruitment failures in a range of higher trophic-level marine predators. Where predator species are not able to accommodate by switching to other prey species, population-level changes will follow. The Southern Ocean, though oceanographically interconnected, is not a single ecosystem and different areas are dominated by different food webs. Where species occupy different positions in different regional food webs, there is the potential to make predictions about future change scenarios.

Assessing the effects of climate change on US West Coast sablefish productivity and on the performance of alternative management strategies

2019 ◽  
Vol 76 (6) ◽  
pp. 1524-1542
Author(s):  
Melissa A Haltuch ◽  
Z Teresa A’mar ◽  
Nicholas A Bond ◽  
Juan L Valero
Keyword(s):  
Climate Change ◽  
West Coast ◽  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Management Strategies ◽  
Climate Impacts ◽  
Global Climate Models ◽  
The Impact ◽  
Us West

Abstract US West Coast sablefish are economically valuable, with landings of 11.8 million pounds valued at over $31 million during 2016, making assessing and understanding the impact of climate change on the California Current (CC) stock a priority for (1) forecasting future stock productivity, and (2) testing the robustness of management strategies to climate impacts. Sablefish recruitment is related to large-scale climate forcing indexed by regionally correlated sea level (SL) and zooplankton communities that pelagic young-of-the-year sablefish feed upon. This study forecasts trends in future sablefish productivity using SL from Global Climate Models (GCMs) and explores the robustness of harvest control rules (HCRs) to climate driven changes in recruitment using management strategy evaluation (MSE). Future sablefish recruitment is likely to be similar to historical recruitment but may be less variable. Most GCMs suggest that decadal SL trends result in recruitments persisting at lower levels through about 2040 followed by higher levels that are more favorable for sablefish recruitment through 2060. Although this MSE suggests that spawning biomass and catches will decline, and then stabilize, into the future under both HCRs, the sablefish stock does not fall below the stock size that leads to fishery closures.

Evidence for egg brooding and parental care in icefish and other notothenioids in the Southern Ocean

2006 ◽  
Vol 18 (2) ◽  
pp. 223-227 ◽  
Author(s):  
K.-H. Kock ◽  
L.K. Pshenichnov ◽  
A.L. Devries
Keyword(s):  
Southern Ocean ◽  
Parental Care ◽  
Incubation Period ◽  
Fish Species ◽  
Ross Sea ◽  
Antarctic Fish ◽  
Size And Shape ◽  
Relative Fecundity ◽  
Egg Carrying ◽  
Egg Brooding

One of the least known Antarctic fish species is the icefish Chionobathyscus dewitti described first in 1978. Some of its reproductive characteristics appear to be similar to other channichthyids of similar size and shape. Females close to spawning have gonado–somatic indices (GSIs) of more than 20, and absolute fecundity was 2967 to 15612 oocytes in females 33–62 cm long. Relative fecundity was 7.6 in one female. Spawning has been observed in the Ross Sea at 1300 to 1500 m depth from January to March. Chionobathyscus dewitti may exhibit a remarkable egg carrying behaviour: eggs stick together in batches around the pelvic fins of females. The comparatively large number of mature males observed with no indication of an egg batch attached to their ventral fins makes it unlikely that males are involved in egg carrying. The few larvae of C. dewitti caught so far occurred from October onwards. Their size indicates that they have hatched as early as September. This suggests an incubation period of at least six months. We compare this with parental care reported in other notothenioids.

scholarly journals Peatlands and the carbon cycle: from local processes to global implications – a synthesis

2008 ◽  
Vol 5 (5) ◽  
pp. 1475-1491 ◽  
Author(s):  
J. Limpens ◽  
F. Berendse ◽  
C. Blodau ◽  
J. G. Canadell ◽  
C. Freeman ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Surface ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Trace Gas ◽  
Future Climate Change ◽  
Small Scale ◽  
Ecosystem Structure ◽  
Positive Feedbacks

Abstract. Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15–30% of the world's soil carbon (C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change. The main drivers controlling C fluxes are largely scale dependent and most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange (NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors. Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales.

scholarly journals LOCAL KNOWLEDGE OF CIPATAT KOLOT ON THE CLIMATE ADAPTATION: SEED, ORGANIC FERTILIZER, AND HARVEST PROCESSING

2021 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Bahagia Bahagia ◽  
Fachruddin Majeri Mangunjaya ◽  
Zuzy Anna ◽  
Rimun - Wibowo ◽  
Muhammad Shiddiq Ilham Noor
Keyword(s):  
Climate Change ◽  
Indigenous Peoples ◽  
Climate Adaptation ◽  
Global Climate ◽  
Organic Fertilizer ◽  
Management Strategies ◽  
Sampling Technique ◽  
Organic Fertilizers ◽  
Screening Process ◽  
Purposive Sampling

Climate change is characterized by several elements, namely unpredictable rainy and dry seasons, floods and unpredictable droughts. This study aims to determine the indigenous peoples’ local wisdom in adapting to climate change, which includes screening process of local paddy seeds, the use of organic fertilizers, and traditional harvest management strategies. The method used in this research is the qualitative research method combined with the ethnographic approach. This method is applied based on the consideration that the topic of this research is related to the culture and social of indigenous peoples. The data was collected by means of in-depth interviews, observation, and documentation. Informants were selected by using the purposive sampling technique. The results were scrutinized carefully by means of the triangulation process. The results of the study show the facts that the way indigenous peoples deal with climate change is by physically and physiologically selecting seeds and storing seeds for three months so that the seeds will grow stronger. In addition, they only selects paddies that has reached a full state of growth, that is mature to avoid going rotten even though the climate change occurs. Then, they have the traditional rice dryers to get rice dried, thereby enabling those to be more climate-resistant. They also use the organic fertilizer to reduce the production of emissions as a cause of global climate change. Perubahan iklim dapat diamati mulai dari musim penghujan dan musim kering yang tidak menentu, bencana banjir, dan kekeringan yang sulit untuk diprediksi. Penelitian ini bertujuan untuk mengetahui kearifan lokal pada masyarakat adat dalam beradaptasi terhadap perubahan iklim mulai dari seleksi benih padi lokal, penggunaan pupuk organik, dan manajemen panen secara tradisional. Metode yang digunakan adalah kualitatif dengan pendekatan etnografi. Metode ini diterapkan karena penelitian berkaitan dengan budaya dan sosial masyarakat adat. Pengumpulan data dilakukan melalui wawancara mendalam, observasi, dan dokumentasi. Pemilihan informan menggunakan teknik purposive sampling. Kemudian, hasil pengumpulan data diteliti dengan cermat melalui triangulasi. Hasil penelitian menunjukkan bahwa masyarakat adat mengatasi perubahan iklim dengan melakukan seleksi benih secara fisik dan fisiologi dan menyimpan benih sampai dengan 3 bulan agar benih kuat dalam pertumbuhannya. Disamping itu, petani adat harus memanen padi matang sehingga padi tidak mengalami pembusukan meskipun terjadi perubahan iklim. Kemudian, masyarakat menggunakan mengelola hasil panen dengan alat pengering padi tradisional sehingga hasil panen padi lebih tahan iklim. Setelah itu, masyarakat adat menggunakan pupuk organik sebagai cara untuk memperkecil produksi emisi sebagai penyebab perubahan iklim secara global.

scholarly journals Revisiting the larval dispersal black box in the Anthropocene

2018 ◽  
Vol 75 (6) ◽  
pp. 1841-1848 ◽  
Author(s):  
Kit Yu Karen Chan ◽  
Mary A Sewell ◽  
Maria Byrne
Keyword(s):  
Climate Change ◽  
Larval Dispersal ◽  
Population Distribution ◽  
Global Climate ◽  
Management Strategies ◽  
Black Box ◽  
Study Approach ◽  
Theoretical Approaches ◽  
The Face ◽  
Multi Phase

Abstract Many marine organisms have a multi-phase life history and rely on their planktonic larvae for dispersal. Despite the important role of larvae in shaping population distribution and abundance, the chemical, physical, and biological factors that shape larval fate are still not fully understood. Shedding light into this larval dispersal “black box” has become critical in the face of global climate change, primarily due to the importance of larval dispersal in formulating sound conservation and management strategies. Focusing on two major stressors, warming and acidification, we highlight the limitations of the current species-by-species, lab-based study approach, and particularly the lack of consideration of the larval experience along the dispersive pathway. Measuring organismal responses to environmentally relevant climate change stress demands an improved documentation of the physical and biological conditions that larvae experience through ontogeny, which in turn requires updated empirical and theoretical approaches. While there are meaningful between taxa comparisons to be made by larval ecologists, to peek into the dispersal black box and to investigate the larger scale consequences of altered dispersal requires innovative collaborations between ecologists, oceanographers, molecular biologists, statisticians, and mathematicians.

Antarctica and Africa: Narrating alternate futures

Polar Record ◽  
2019 ◽  
Vol 55 (5) ◽  
pp. 347-350
Author(s):  
Charne Lavery
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Southern Ocean ◽  
Sea Level ◽  
Global Climate ◽  
African Literature ◽  
The Arts ◽  
Ongoing Work ◽  
Cultural Terms ◽  
History Of

AbstractAfrica has been marginalised in the history of Antarctica, a politics of exclusion (with the exception of Apartheid South Africa) reflected unsurprisingly by a dearth of imaginative, cultural and literary engagement. But, in addition to paleontological and geophysical links, Antarctica has increasing interrelationship with Africa’s climactic future. Africa is widely predicted to be the continent worst affected by climate change, and Antarctica and its surrounding Southern Ocean are uniquely implicated as crucial mediators for changing global climate and currents, rainfall patterns, and sea level rise. This paper proposes that there are in fact several ways of imagining the far South from Africa in literary and cultural terms. One is to read against the grain for southern-directed perspectives in existing African literature and the arts, from southern coastlines looking south; another is to reexamine both familiar and new, speculative narratives of African weather – drought, flood and change – for their Antarctic entanglements. In the context of ongoing work on postcolonial Antarctica and calls to decolonise Antarctic studies – such readings can begin to bridge the Antarctica–Africa divide.

scholarly journals Late Oligocene obliquity-paced contourite sedimentation in the Wilkes Land margin of East Antarctica: implications for paleoceanographic and ice sheet configurations

2017 ◽  
Author(s):  
Ariadna Salabarnada ◽  
Carlota Escutia ◽  
Ursula Röhl ◽  
C. Hans Nelson ◽  
Robert McKay ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Global Climate ◽  
Ice Sheet ◽  
East Antarctica ◽  
Late Oligocene ◽  
Early Oligocene ◽  
Geochemical Parameters ◽  
Wilkes Land

Abstract. The late Oligocene experienced atmospheric concentrations of CO2 between 400 and 750 ppm, which are within the IPCC projections for this century, assuming unabated CO2 emissions. However, Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved, but are important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under such CO2 scenarios. Here, we present late Oligocene (26–25 Ma) ice sheet and paleoceanographic reconstructions recorded in sediments recovered by IODP Site U1356, offshore of the Wilkes Land margin in East Antarctica. Our study, based on a combination of sediment facies analysis, physical properties, and geochemical parameters, shows that glacial and interglacial sediments are continuously reworked by bottom-currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted to represent a northward shift of westerly winds and surface oceanic fronts. During interglacial times, more oxygenated and ventilated conditions prevailed, which suggests enhanced mixing of the water masses with enhanced current velocities. Micritic limestone intervals within some of the interglacial facies represent warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g. North Atlantic sourced deep water) had a greater influence on the site. The lack of iceberg rafted debris (IRD) throughout the studied interval contrasts with early Oligocene and post-Oligocene sections from Site U1356 and with late Oligocene strata from the Ross Sea (CRP and DSDP 270), which contain IRD and evidence for coastal sea ice and glaciers. These observations, supported by elevated paleotemperatures and the absence of sea-ice, suggest that between 26 and 25 Ma reduced glaciers or ice caps occupied the terrestrial lowlands of the Wilkes Land margin. Unlike today, the continental shelf was not over-deepened, and thus marine-based ice sheet expansion was likely limited to coastal regions. Combined, these data suggest that ice sheets in the Wilkes Subglacial Basin were largely land-based, and therefore retreated as a consequence of surface melt during late Oligocene, rather than direct ocean forcing and marine ice sheet instability processes as it did in younger past warm intervals. Spectral analysis on late Oligocene sediments from the eastern Wilkes Land margin show that the glacial-interglacial cyclicity and resulting displacements of the Southern Ocean frontal systems between 26–25 Ma were forced by obliquity.

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