Papers by Katharina Alter
Nature communications, Apr 3, 2024
Global change biology, May 1, 2024
Marine Pollution Bulletin, Dec 31, 2023
bioRxiv (Cold Spring Harbor Laboratory), Dec 22, 2023
Declarations and statements Declaration of originality This thesis contains no material which has... more Declarations and statements Declaration of originality This thesis contains no material which has been accepted for a degree or diploma by the University or any other institution, except by way of background information and duly acknowledged in the thesis, and to the best of my knowledge and belief no material previously published or written by another person except where due acknowledgement is made in the text of the thesis, nor does the thesis contain any material that infringes copyright.
Journal of Fish Biology, Sep 28, 2022
In marine fishes, the timing of spawning determines the environment offspring will face and, ther... more In marine fishes, the timing of spawning determines the environment offspring will face and, therefore, the chances of early life stage survival. Different waves of Atlantic herring Clupea harengus spawn throughout spring in the western Baltic Sea, and the survival of offspring from early in the season has been low in the most recent decade. The authors assessed changes in egg traits from early, middle and late phases of the spawning season to examine whether seasonal and/or maternal effects influenced embryo survival. At each phase, fertilized eggs of six to eight females were incubated at two temperatures (7 and 13°C), and egg size, fertilization success, mortality and time to hatch were recorded. A compilation of data from 2017 to 2020 spawning seasons indicated that mean total length of females decreased with progression of the season and increasing in situ water temperature. For the sub‐set of females used in the laboratory study, early spawners were 7.6% larger and produced 14.2% larger eggs than late‐spring spawners. Fertilization success was consistently high (&gt;90%), and mortality to hatch was low (&lt;3%). Neither the former nor latter were influenced by season, but both were influenced by maternity. This significant female effect was, however, not related to any maternal trait measured here (total length, Fulton's condition factor or age). There was no maternal effect on development rate at 7 or 13°C. The results suggest that intrinsic differences among females or among spawning waves are unlikely to markedly contribute to the poor survival observed for progeny from early in the season in this population and point towards other extrinsic factors or processes acting on eggs or early larval stages (e.g., seasonal match–mismatch dynamics with prey) as more likely causes of mortality.
Cell Stress & Chaperones, Jun 14, 2011
Climate warming involves not only a rise of air temperature means, but also more frequent heat wa... more Climate warming involves not only a rise of air temperature means, but also more frequent heat waves in many regions on earth, and is predicted to intensify physiological stress especially in extremely changeable habitats like the intertidal. We investigated the heat-shock response (HSR) and enzymatic antioxidant defense levels of Patagonian shallow-water limpets, adapted to distinct tidal exposure conditions in the sub-and intertidal. Limpets were sampled in the temperate Northern Patagonia and the subpolar Magellan region. Expression levels of two Hsp70 genes and activities of the antioxidants superoxide dismutase (SOD) and catalase (CAT) were measured in submerged and 2-and 12-h air-exposed specimens. Air-exposed Patagonian limpets showed a tiered HSR increasing from South to North on the latitudinal gradient and from high to low shore levels on a tidal gradient. SOD activities in the Magellan region correlated with the tidal rhythm and were higher after 2 and 12 h when the tide was low at the experimental site compared to the 6 h value taken at high tide. This pattern was observed in intertidal and subtidal specimens, although subtidal individuals are little affected by tides. Our study shows that long-term thermal adaptation shapes the HSR in limpets, while the oxidative stress response is linked to the tidal rhythm. Close to the warm border of their distribution range, energy expenses to cope with stress might become overwhelming and represent one cause why the limpets are unable to colonize the shallow intertidal zone.
Reviews in Aquaculture, May 7, 2015
ABSTRACT
Reviews in Fish Biology and Fisheries, Jan 18, 2023
Social Science Research Network, 2022
To predict the potential impacts of climate change on marine organisms, it is critical to underst... more To predict the potential impacts of climate change on marine organisms, it is critical to understand how multiple stressors constrain the physiology and distribution of species. We evaluated the effects of seasonal changes in seawater temperature and near-future ocean acidification (OA) on organismal and sub-organismal traits associated with the thermal performance of Eleginops maclovinus, a sub-Antarctic notothenioid species with economic importance to sport and artisanal fisheries in southern South America. Juveniles were exposed to mean winter and summer sea surface temperatures (4 and 10 ºC) at present-day and near-future pCO2 levels (~500 and 1800 μatm). After a month, the Critical Thermal maximum and minimum (CTmax, CTmin) of fish were measured using the Critical Thermal Methodology and the aerobic scope of fish was measured based on the difference between their maximal and standard rates determined from intermittent flow respirometry. Lipid peroxidation and the antioxidant capacity were also quantified to estimate the oxidative damage potentially caused to gill and liver tissue. Although CTmax and CTmin were higher in individuals acclimated to summer versus winter temperatures, the increase in CTmax was minimal in juveniles exposed to the near-future compared to present-day pCO2 levels (there was a significant interaction between temperature and pCO2 on CTmax). The reduction in the thermal tolerance range under summer temperatures and nearfuture OA conditions was associated with a reduction in the aerobic scope observed at the elevated pCO2 level. Moreover, an oxidative stress condition was detected in the gill and liver tissues. Thus, chronic exposure to OA and the current summer temperatures pose limits to the thermal performance of juvenile E. maclovinus at the organismal and sub-organismal levels, making this species vulnerable to projected climate-driven warming.
Science of The Total Environment, Aug 1, 2021
Ocean acidification has the potential to negatively affect marine ecosystems by influencing the d... more Ocean acidification has the potential to negatively affect marine ecosystems by influencing the development and metabolism of key members of food webs. The garfish, Belone belone, is an ecologically important predator in European regional seas and it remains unknown how this species will be impacted by projected changes in climate. We artificially fertilized and reared garfish embryos until hatch at present (400 μatm) and future (1300 μatm) pCO 2 levels within three temperature treatments, i.e. two daily warming regimes and one constant high temperature (17°C). For the two warming treatments, embryos were fertilized at 13°C and experienced 0.1 or 0.3°C/day warming. The 0.1°C/day treatment served as control: 13°C was the in situ temperature of parental fish in the Southwest Baltic Sea and 0.1°C/day is the average warming rate experienced by embryos of this population in nature. Survival was drastically reduced at both future pCO 2 and at the constant high temperature while the highest survival in any treatment was observed at 0.3°C/day warming. The proportion of embryos with morphological deformities increased with elevated pCO 2 but not temperature. Hatch characteristics and physiological measures such as heart rate and critical thermal ranges, however, were not affected by pCO 2 but were influenced by temperature. Our results suggest that garfish in the Baltic Sea will benefit from projected increased rates of spring warming but not the concomitant increase in pCO 2. Previous studies on the impacts of ocean acidification on resident fishes in the Baltic Sea indicate that this piscivorous fish is at higher risk compared to its prey which may have broader implications for the future trophodynamic structure and function of the coastal food web.
Reviews in Fish Biology and Fisheries, Dec 4, 2022
Understanding the drivers behind fluctuations in fish populations remains a key objective in fish... more Understanding the drivers behind fluctuations in fish populations remains a key objective in fishery science. Our predictive capacity to explain these fluctuations is still relatively low, due to the amalgam of interacting bottom-up and top-down factors, which vary across time and space among and within populations. Gaining a mechanistic understanding of these recruitment drivers requires a holistic approach, combining field, experimental and modelling efforts. Here, we use the Western Baltic Spring-Spawning (WBSS) herring (Clupea harengus) to exemplify the power of this holistic approach and the high complexity of the recruitment drivers (and their interactions). Since the early 2000s, low recruitment levels have promoted intense research on this stock. Our literature synthesis suggests that the major drivers are habitat compression of the spawning beds (due to eutrophication and coastal modification mainly) and warming, which indirectly leads to changes in spawning phenology, prey abundance and predation pressure. Other factors include increased intensity of extreme climate events and new predators in the system. Four main knowledge gaps were identified related to life-cycle migration and habitat use, population structure and demographics, life-stage specific impact of multi-stressors, and predator-prey
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, Jul 18, 2021
The underlying mechanisms controlling growth heterosis in marine invertebrates remain poorly unde... more The underlying mechanisms controlling growth heterosis in marine invertebrates remain poorly understood. We used pure blacklip (Haliotis rubra) and greenlip (Haliotis laevigata) abalone, as well as their hybrid, to test whether differences in movement and/or aerobic versus anaerobic energy use are linked to a purported increased growth rate in hybrids. Abalone were acclimated to control (16 °C) and typical summer temperatures (23 °C), each with oxygen treatments of 100% air saturation (O2sat) or 70% O2sat. The experiment then consisted of two phases. During the first phase (chronic exposure), movement and oxygen consumption rates (ṀO2) of abalone were measured during a 2 day observation period at stable acclimation conditions. Additionaly, lactate dehydrogenase (LDH) and tauropine dehydrogenase (TDH) activities were measured. During phase two (acute exposure), O2sat was raised to 100% for abalone acclimated to 70% O2sat followed by an acute decrease in oxygen to anoxia for all acclimation groups during which movement and ṀO2 were determined again. During the chronic exposure, hybrids and H. laevigata moved shorter distances than H. rubra. Resting ṀO2, LDH and TDH activities, however, were similar between abalone types but were increased at 23 °C compared to 16 °C. During the acute exposure, the initial increase to 100% O2sat for individuals acclimated to 70% O2sat resulted in increased movement compared to individuals acclimated to 100% O2sat for hybrids and H. rubra when compared within type of abalone. Similarly, ṀO2 during spontaneous activity of all three types of abalone previously subjected to 70% O2sat increased above those at 100% O2sat. When oxygen levels had dropped below the critical oxygen level (Pcrit), movement in hybrids and H. laevigata increased up to 6.5-fold compared to movement above Pcrit. Differences in movement and energy use between hybrids and pure species were not marked enough to support the hypothesis that the purportedly higher growth in hybrids is due to an energetic advantage over pure species.
Journal of Shellfish Research, Oct 1, 2016
On Australian aquaculture farms, early life stages of abalone are reared under controlled abiotic... more On Australian aquaculture farms, early life stages of abalone are reared under controlled abiotic and biotic conditions in an attempt to optimize individual growth and reduce potential stressors. Yet, physiological responses to the rearing conditions are largely unknown. This study tests if commercial stocking densities, light conditions, and oxygen levels influence the oxygen consumption rate (_ MO 2) of early life stages of Haliotis rubra and Haliotis laevigata hybrids at a standard commercial hatchery temperature of 16°C. Oxygen consumption rate of fertilized eggs and larvae in the trochophore, mid-veliger, and early benthic veliger stages were measured at densities from 100 to 2,400 individuals/ml, in light and dark conditions and oxygen levels of 100%-0% air saturation (% O 2 sat). Neither density nor light conditions affected _ MO 2 of any of the tested life stages. Normoxic _ MO 2 varied across developmental stage and was higher in the actively swimming mid-veliger stages (114.92 ± 2.68 pmol O 2 /ind/h) in comparison with less active earlier (49.48 ± 2.33 pmol O 2 /ind/h) and later life stages (65.90 ± 3.05 pmol O 2 /ind/h). Critical oxygen tensions, taken as the point at which animals could no longer maintain _ MO 2 , ranged from 22.7% ± 2.7% O 2 sat in fertilized eggs to 14.0% ± 1.0% O 2 sat in mid-veliger larvae. These results suggest that current conditions in Australian abalone aquaculture farms should not negatively impact the development of early life stages of hybrid abalones.
Science of The Total Environment, Jun 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Zenodo (CERN European Organization for Nuclear Research), Jun 6, 2023
Reviews in Fish Biology and Fisheries, Jan 18, 2023
Conflicting results remain on how climate change affects the biological performance of different ... more Conflicting results remain on how climate change affects the biological performance of different marine taxa, hindering our capacity to predict the future state of marine ecosystems. Using a novel meta-analytical approach, we tested for directional changes and deviations across biological responses of fish and invertebrates from exposure to warming (OW), acidification (OA), and their combination. In addition to the established effects of climate change on calcification, survival and metabolism, we found deviations in the physiology, reproduction, behavior, and development of fish and invertebrates, resulting in a doubling of responses significantly affected when compared to directional changes. Widespread deviations of responses were detected even under moderate (IPCC RCP6-level) OW and OA for 2100, while directional changes were mostly limited to more severe (RCP 8.5) exposures. Because such deviations may result in ecological shifts impacting ecosystem structure and processes, our...
Reviews in Fish Biology and Fisheries
Understanding the drivers behind fluctuations in fish populations remains a key objective in fish... more Understanding the drivers behind fluctuations in fish populations remains a key objective in fishery science. Our predictive capacity to explain these fluctuations is still relatively low, due to the amalgam of interacting bottom-up and top-down factors, which vary across time and space among and within populations. Gaining a mechanistic understanding of these recruitment drivers requires a holistic approach, combining field, experimental and modelling efforts. Here, we use the Western Baltic Spring-Spawning (WBSS) herring (Clupea harengus) to exemplify the power of this holistic approach and the high complexity of the recruitment drivers (and their interactions). Since the early 2000s, low recruitment levels have promoted intense research on this stock. Our literature synthesis suggests that the major drivers are habitat compression of the spawning beds (due to eutrophication and coastal modification mainly) and warming, which indirectly leads to changes in spawning phenology, prey...
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Papers by Katharina Alter