Rising Sea Water Research Articles

De novo assembly of the transcriptome of scleractinian coral, Anomastraea irregularis and analyses of its response to thermal stress.

Rising seawater temperatures cause coral bleaching. The molecular responses of the coral holobiont under stress conditions, determine the success of the symbiosis. Anomastraea irregularis is a hard coral commonly found in the harsh intertidal zones of the south coast of KwaZulu-Natal (KZN), South Africa, where it thrives at the very margins of hard coral distribution in the Western Indian Ocean. To identify the possible molecular and cellular mechanisms underlying its resilience to heat stress, experimental and control nubbins were exposed to temperatures of 29 and 19°C respectively for 24h. The transcriptome was assembled de novo from 42.8 million quality controlled 63bp paired-end short sequence reads obtained via RNA sequencing (RNA-seq). The assembly yielded 333,057 contigs (> 500bp = 55,626, Largest = 6341bp N50 = 747bp). 1362 (1.23%) of the transcripts were significantly differentially expressed between heat stressed and control samples. Log fold change magnitudes among individual genes ranged from - 4.6 to 7.2. Overall, the heat stress response in the A. irregularis constituted a protective response involving up regulation of apoptosis and SUMOylation. Gene ontology (GO) analyses revealed that heat stress in the coral affected the metabolism, protein synthesis, photosynthesis, transport and cytoskeleton. This is the first study to produce a reference transcriptome of this coral species and analyze its response to heat stress. The assembled transcriptome also presents a valuable resource for further transcriptomic and genomic studies.

Hydrological analysis of moveable weir planning for tidal flood handling in Cilacap, Central Java

Global warming resulting in climate change has become a new disaster in the world. One of the changes in climate is the rise of sea water to land surface, which causes tidal flooding. One area that experienced tidal flooding was Kawunganten District, Cilacap, Central Java Province. The area is traversed by the Parit River with the river estuary located in Ujungmanik Village. The problem of tidal flooding in Kawunganten District can be overcome by constructing a moveable weir in the estuary of the Parit River. In planning on the moveable weir, a hydrological analysis is needed to determine the flood discharge plan. Rainfall data used as a basis for calculation of flood discharge at the study site is rainfall data from 3 observation stations namely Cilacap Station, Majenang Station and Ujungbarang Station with the recording period from 2009 to 2018. Calculation of rainfall plan is done using the Pearson Log Method III with a value of T100 = 165.463 mm. The results of the calculation of the flood discharge plan with the haspers method Q100 = 280.989 m3/sec, while the weduwen method Q100 = 132.804 m3/sec and the HSS Nakayasu method Q100 = 102.444. Furthermore, an analysis of tides on the coast of Cilacap Regency with the results of MWL (Mean Water Level) = 110 cm, LWL (Low Water Level) = 20 cm, HWL (High Water Level) = 220 cm.

No standard lock gates for the new sea lock in IJmuiden, the largest lock in the world

ABSTRACTIn the Dutch city of IJmuiden, a new sea lock is currently under construction. With a lock chamber of 500 m long and 70 m wide, it will be the largest lock in the world. The latest generation of seagoing vessels will be able to access the harbour of Amsterdam using this lock. At the same time, at an altitude of 8.85 meters above sea level, the Netherlands are protected from the rising sea water for the next two centuries. The lock must be constructed in between of the existing operational locks. Because of this lack of space, the water levelling system is incorporate in the rolling gates. The required performance of the gates as well as the drive mechanism, in terms of reliability, availability, maintainability, safety and robustness), was highly governing during the design process, and resulted in a final design that cannot be described as standard.

Effects of the interaction between temperature and steroid hormones on gametogenesis and sex ratio in the European flat oyster (Ostrea edulis)

Throughout Europe, populations of Ostrea edulis have been in decline since the 1970s. Temperature has an important influence on physiological, biochemical and reproductive attributes of oysters. It is also the most easily modulated environmental factor in hatcheries, so it is useful to understand the implications of temperature variation in driving gametogenesis and sex development in a protandrous sequential hermaphrodites such as O. edulis. To understand the effect of temperature on gametogenesis and sex ratio, as well as the potential mechanism of sex determination through the role of steroid hormone homologues, oysters were exposed to three temperatures (10, 14, and 18 °C) for four months. Gametogenic stage and sex ratio were assessed histologically for each treatment. In parallel, concentrations of estradiol (E2)- and testosterone (T)- were determined in developing gonads. Our data show that by some biometric parameters, gametogenesis and sex ratio were significantly influenced by temperature during the experiment. There was a weak but significant correlation between E2 and T concentration during the treatments. However, and importantly, a direct relation between gonadal maturation, sex determination and hormones concentration was not found. These results suggest that gametogenesis and sex determination are predominantly affected by temperature in this species, and that steroids may not be actively involved as endogenous modulators in sex determination. Rising sea water temperatures and warmer condition through the year could cause an accelerated gametogenesis and skewed sex ratios in natural populations of O. edulis.

Climate Change Challenges and Djibouti

In the once fertile area around Sagalou village, rising sea water has salinated and blocked former water sources. Djibouti, January 2019. Courtesy of Susan SchulmanDjibouti is profoundly affected b...

Climate change and the mitigating tool of salvage archaeology: The case of the Fort Kongensten site at Ada Foah, Ghana

In the ongoing attempts at lessening the hydra-headed impacts of climate change, this paper explored the strategic use of salvage archaeology in the scientific retrieval and documentation of heritage remains and sites under the threat of climate change. In doing so, the research examined the effects of climate change and global warming on coastal heritage resources. Specifically, in Ghana, sea levels have been steadily rising over the centuries leading to the erosion of coastlines and the submergence of historic coastal settlements to about 110 metres inland. A historic Danish Fort Kongensten constructed in 1783 along the coast of Ada-Foah in Ghana, for example, has been totally eroded away by the rising sea water. This paper assesses how salvage archaeology was used to retrieve, document and conserve cultural materials associated with the fort. It also explored the extent to which salvage archaeology and anthropology can be used as tools in climate change mitigation projects in impacted zones.

Immersive Virtual Reality Field Trips Facilitate Learning About Climate Change.

Across four studies, two controlled lab experiments and two field studies, we tested the efficacy of immersive Virtual Reality (VR) as an education medium for teaching the consequences of climate change, particularly ocean acidification. Over 270 participants from four different learning settings experienced an immersive underwater world designed to show the process and effects of rising sea water acidity. In all of our investigations, after experiencing immersive VR people demonstrated knowledge gains or inquisitiveness about climate science and in some cases, displayed more positive attitudes toward the environment after comparing pre- and post-test assessments. The analyses also revealed a potential post-hoc mechanism for the learning effects, as the more that people explored the spatial learning environment, the more they demonstrated a change in knowledge about ocean acidification. This work is unique by showing distinct learning gains or an interest in learning across a variety of participants (high school, college students, adults), measures (learning gain scores, tracking data about movement in the virtual world, qualitative responses from classroom teachers), and content (multiple versions varying in length and content about climate change were tested). Our findings explicate the opportunity to use immersive VR for environmental education and to drive information-seeking about important social issues such as climate change.

Numerical modeling of seawater intrusion in karstic aquifer, Northwestern Coast of Egypt

The growing population and increasing of the urbanization activities at the Egyptian coastal areas create a great demand on groundwater. El Negila which is located on the Northwestern coast of Egypt is of great environmental, economic, and social importance, so the sustainable management and preservation of the groundwater quantity and quality is imperative. Such task can be addressed through modeling tools that take into account both the human impacts and the effects of climate changes on the hydrogeological system. A variable-density flow model (SEAWAT) had been used to investigate the extent of the seawater intrusion the study area, and to introduce an effective management policy for sustainable development of the groundwater system. An attempt had been made for model calibration; based on adjusting the hydraulic head of the hydrogeological system with respect to the lineaments frequency in the study area. The calibrated numerical model showed the limited extent of the seawater intrusion in the study area under current recharge and abstraction conditions, in addition to that, the model was validated using hydrochemical and stable isotopic data. The aquifer response to different stressing pumping scenario has been tested and predicted up to the year 2022. Furthermore, the impact of rising the seawater level as a result of rapid climatic change was assessed, with pumping stress of the second scenario. It was concluded that the tableland area acts as recharge source and providing an opportunity of recharging the karstic aquifer in the study area especially through the lineaments. The extent of seawater intrusion in the study area for the karstic aquifer is limited, and would increase under the induced activities of pumping as well as seawater rise conditions. A range of withdrawal rate from the study area was recommended to avoid more invasions from seawater.

Assessing the Contribution of Demographic Growth, Climate Change, and the Refugee Crisis on Seawater Intrusion in the Tripoli Aquifer

As a major hotspot of climate change, Lebanon suffers from a water resources crisis enhanced by the increase of anthropogenic activities. In this paper, the impacts of climate change and of the Syrian refugee crisis are combined with the impact of demographic growth to assess their aggregated impact on seawater intrusion in the Tripoli aquifer. A hydrogeological model is used to assess the seawater intrusion evolution for the next 25 years with respect to three phenomena: seawater rise, variation of incoming freshwater flux, and the change of the extraction rate of the pumping wells. Our study shows that the freshwater/seawater interface will move forward inland about 103 m in the next 25 years, leading to the salinization of the aquifer at the position of the pumping wells. Only about 1% of the advancement of the interface is associated with seawater rise; the remaining contributions are 79% from climate change and 20% from demographic growth. Adding the impact of migration reduces the contribution of climate change from 79% to 52%. The results suggest that the remediation solutions and recommendations should take into account the long-term impacts of climate change and the impact of population migration.

Vibrio spp. infections.

Vibrio is a genus of ubiquitous bacteria found in a wide variety of aquatic and marine habitats; of the >100 described Vibrio spp., ~12 cause infections in humans. Vibrio cholerae can cause cholera, a severe diarrhoeal disease that can be quickly fatal if untreated and is typically transmitted via contaminated water and person-to-person contact. Non-cholera Vibrio spp. (for example, Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio vulnificus) cause vibriosis - infections normally acquired through exposure to sea water or through consumption of raw or undercooked contaminated seafood. Non-cholera bacteria can lead to several clinical manifestations, most commonly mild, self-limiting gastroenteritis, with the exception of V. vulnificus, an opportunistic pathogen with a high mortality that causes wound infections that can rapidly lead to septicaemia. Treatment for Vibrio spp. infection largely depends on the causative pathogen: for example, rehydration therapy for V. cholerae infection and debridement of infected tissues for V. vulnificus-associated wound infections, with antibiotic therapy for severe cholera and systemic infections. Although cholera is preventable and effective oral cholera vaccines are available, outbreaks can be triggered by natural or man-made events that contaminate drinking water or compromise access to safe water and sanitation. The incidence of vibriosis is rising, perhaps owing in part to the spread of Vibrio spp. favoured by climate change and rising sea water temperature.

The Spatial and Temporal Variability of Air-Sea CO2 Fluxes and the Effect of Net Coral Reef Calcification in the Indonesian Seas: A Numerical Sensitivity Study

A numerical model system was developed and applied to simulate air-sea fluxes of CO2 and coral reef calcification in the Indonesian Seas and adjacent ocean basin for the period 1960 to 2014 on a fine resolution grid (ca. 11 km) in order to study their response to rising sea water temperatures and CO2 concentrations in the atmosphere. Results were analyzed for different sub-regions on the Sunda Shelf (Gulf of Thailand, Malacca Strait, Java Sea) and show realistic and different levels, signs and pronounced temporal variability in air-sea CO2 flux. The Gulf of Thailand changes from an atmospheric CO2 sink during the boreal winter to a CO2 source in summer due to higher water temperatures, while other sub-regions as well as the entire averaged Sunda Shelf act as a continuous source of CO2 for the atmosphere. However, increasing atmospheric CO2 concentrations weakened this source function during the simulation period. In 2007, the model simulations showed even a first flux inversion, in course of which the Java Sea took up CO2 . The simulated trends suggest that the entire Sunda Shelf will turn into a permanent sink for atmospheric CO2 within the next 30 to 35 years if current trends remain constant. Considering the period between 2010 and 2014, coral reef calcification enhanced the average CO2 emission of the Sunda Shelf by more than 10 % from 15 to 17 Tg C yr−1 due to lowering the pH and increasing the partial pressure of CO2 in surface water. During the entire period of simulation, net reef calcification decreased although increasing seawater temperature mitigated effects of reduced CO2 emission and the resulting decrease of the pH values on reef calcification. Our realistic simulation results already without consideration of any biological processes suggest that biological processes taking up and releasing CO 2 are currently well balanced in these tropical regions. However, the counteracting effects of climate change on the reef calcification, on other biological processes and the carbonate system need to be investigated in more detail. SST ◦increased by about 0.6 C during the last 55 years, while SSS decreased by about 0.7 psu.

Spatial and vertical variations of perfluoroalkyl acids (PFAAs) in the Bohai and Yellow Seas: Bridging the gap between riverine sources and marine sinks

Perfluoroalkyl acids (PFAAs) are being increasingly reported as emerging contaminants in riverine and marine settings. This study investigated the contamination level and spatial distribution of 17 PFAAs within the depth profile of the Bohai and Yellow Seas using newly detected sampling data from 49 sites (June 29 to July 14, 2016). Moreover, the riverine flux of 11 selected PFAAs in 33 rivers draining into the Bohai and Yellow Seas was estimated from previous studies (2002–2014) in order to establish the relationship between riverine sources and marine sinks. The results showed that the Bohai and Yellow Seas were commonly contaminated with PFAAs: total concentrations of PFAAs in the surface, middle, and bottom zones ranged from 4.55 to 556 ng L−1, 4.61–575 ng L−1, and 4.94–572 ng L−1, respectively. The predominant compounds were PFOA (0.55–449 ng L−1), PFBA (<LOQ-34.5 ng L−1), and PFPeA (<LOQ-54.3 ng L−1), accounting for 10.1–87.0%, 5.2–59.5%, and 0.6–68.6% of the total PFAAs, respectively. In general, the ∑PFAA concentrations showed a slightly decreasing trend with sampling depth. Contamination was particularly severe in Laizhou Bay, fed by the Xiaoqing River and an industrial park known for PFAA production. The total riverine PFAA mass flux into the Bohai and Yellow Seas was estimated to be 72.2 t y−1, of which 94.8% was carried by the Yangtze and Xiaoqing Rivers. As the concentration of short-chain PFAAs begins to rise in seawater, further studies on the occurrence and fate of short-chain PFAAs with special focus on effective control measures would be very timely, particularly in the Xiaoqing River and Laizhou Bay.

Research progress in ecotoxicology of climate change coupled with marine pollutions

Marine pollution has become a global problem since industrialization. Global climate change has also brought significant changes to the marine environment, especially with the continuously increasing atmospheric CO2 concentration. Lots of studies have solely focused on the influences of climate change or environmental pollutants on marine biota and ecosystem, and made some widely-accepted conclusions. However, in the real environment, marine ecosystem is likely suffering more complex impacts than that exposed to either marine pollution or climate change only. Thus research of climate change coupled with marine pollution is being more and more concerned by the government and scientists, and becomes a hotspot in the field of marine environmental science and global climate change. In the present research, effects of climate change (especially rising sea water temperature, acidification and hypoxia) on the biotoxicity of typical marine pollutants (e.g., heavy metals, POPs), as well as the interactions between climate change and marine pollution were summarized. On the one hand, ocean warming, acidification and hypoxia affect the resistance of marine organisms on pollutants, and further affect their sensitivity to pollutants; on the other hand, ocean warming, acidification and hypoxia affect the physical and chemical properties, environmental behaviors and bioavailability of marine pollutants directly, and thus change pollutants’ toxicity indirectly. Therefore, under the coupled stress of climate change and marine pollution, toxic effects of pollutants may not only be the simple superposition of the two alone, but also more complex synergies. For example, ocean warming changes the distribution of POPs between the water-gas phase significantly, which makes POPs migrate to higher latitudes through the grasshopper effect and increases the exposure risk of polar organisms to POPs. Warming increases the solubility of heavy metals in seawater, but also increases the precipitation of metal oxides and hydroxides (reducing the solubility of metal ions) due to the increased rate of chemical reactions. This paradox is a difficulty in the current quantitative study for effects of ocean warming on metal solubility. Ocean acidification promotes the releasing of Cu2+ in forms of carbonate compound, or makes Cd2+ and Hg2+ dissociate from their compounds in the sea water, while heavy metals in forms of free state are generally more toxic to marine organisms than those in forms of compounds, thus exacerbating the toxicity of heavy metals to marine organisms. Hypoxia promotes the reduction of arsenic from the pentavalent state to the trivalent state. The arsenic in the trivalent state binds to the thiol-containing protein in the marine organism and inactivates the acetylcholine (AChE) enzyme. According to the statistical report of literatures, studies related to climate change coupled with marine pollution had been rarely reported before 2003, and have been receiving more and more attentions since 2003. In terms of content, the studies mainly focus on combined effects of acidification-heavy metals (slightly more), acidification-nanomaterials as well as organic matters (less), hypoxia-heavy metals as well as organic matters (small amounts), and warming-heavy metals (small amounts) on marine organisms; focused on the effects of acidification on the transport of marine pollutants in food chains (small amounts); focused on the ecological risk of POPs and mercury in the polar region under the background of climate change (slightly more). These studies have shown that climate change does affect the environmental behavior and biological toxicity of marine pollutants directly or indirectly. Ocean plays an important role in maintaining the Earth’s system and climate regulation. From the perspective of how to protect the ocean scientifically and utilize marine resources reasonably under coupled stress of climate change and marine pollution, authors proposed that following fields should be considered seriously in future: (1) mechanisms underlying the interaction between climate change and marine pollution; (2) effects of coupled stresses between climate change and environmental pollution on ocean primary productivity and carbonate system; (3) problems related to coastal ecological risks.

ВЛИЯНИЕ ФАКТОРОВ СРЕДЫ НА ФОРМИРОВАНИЕ ПРОМЫСЛОВЫХ УЛОВОВ ВОБЛЫ (RUTILUS RUTILUS CASPICUS) В ВОЛГО-КАСПИЙСКОМ И СЕВЕРО-КАСПИЙСКОМ РЫБОХОЗЯЙСТВЕННЫХ ПОДРАЙОНАХ

The article presents analyzes of the influence of long-term see breathing on roach catches. There were studied relations of these indicators within 1959-1976 (low sea-level), 1977-1994 (sea water rise from the minimum to maximum level), 1995-2016 (maximum sea-level falling to modern range). The analysis of longstanding dynamics of roach catches showed the relation with the sea-level fluctuations, under the influence of which bio-productivity of the Caspian Sea is forming. For analysis of the influence of environment conditions on roach catches there was taken the time period of 1975-1988. The results showed the inverse relationship, whereby catches decreased with the increase of flooding. This could happen due to high volumes of water entering the river Delta and preventing from catching fish (depths are increasing, fishing grounds are flooded and fishing ceases). The study shows that the major factors influencing the conditions of the roach fishing are the temperature regime of watercourses in the spring period and the terms of the flooding. In the years of early warming up the water roach came earlier to fishing areas, which created more favorable conditions for fishing. Under the late warming up of the water roach mass run shifted to later periods, when, according to the Rules of the fishery, it is prohibited to use fine-mashed seines. When the terms of the water warming-up to spawning temperatures coincided with the terms of the flooding, roach entered spawning grounds and didn’t stay long in the river, thus its concentrations in the fishing zones took a comparatively short time.

Cenozoic global cooling and increased seawater Mg/Ca via reduced reverse weathering

Authigenic clay minerals formed on or in the seafloor occur in every type of marine sediment. They are recognized to be a major sink of many elements in the ocean but are difficult to study directly due to dilution by detrital clay minerals. The extremely low dust fluxes and marine sedimentation rates in the South Pacific Gyre (SPG) provide a unique opportunity to examine relatively undiluted authigenic clay. Here, using Mg isotopes and element concentrations combined with multivariate statistical modeling, we fingerprint and quantify the abundance of authigenic clay within SPG sediment. Key reactants include volcanic ash (source of reactive aluminium) and reactive biogenic silica on or shallowly buried within the seafloor. Our results, together with previous studies, suggest that global reorganizations of biogenic silica burial over the Cenozoic reduced marine authigenic clay formation, contributing to the rise in seawater Mg/Ca and decline in atmospheric CO2 over the past 50 million years.

Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species.

Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri). To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt) for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average). This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature). The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C) and H. uninervis (33°C), but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The thermal optimum for plant net productivity was lower than ambient summer water temperature in Z. muelleri, indicating likely contemporary heat stress. In contrast, thermal optima of H. uninervis and C. serrulata exceeded ambient water temperature. This study found limited capacity to acclimate: thus the thermal optima can forewarn of both the present and future vulnerability to ocean warming during periods of elevated water temperature.

Post - Tsunami Damages Assessment, Relief and Rehabilitation Measures in the Kanyakumari District, Tamil Nadu, South India

The present study is based on the post tsunami survey conducted in January 2005 along the south west coast of India. This paper illustrates the variation of tsunami intensity along the coasts of Kanyakumari district and the consequent morphological changes occurred in the coastal area during tsunami. 33 coastal habitations of Kanyakumari district faced the wrath of tsunami waves. We have attempted to study shoreline modifications using beach profile survey, tsunami sand deposits, inundation distance, run up elevation and tsunami height. The coastal environment changes through online survey on human losses, housing and shelter, fisheries, agriculture and damages of infrastructure were studied in the study area. The major destructions identified in this area were 3m-4m sea water rise leading to erosion activities and changes in the beach slope variation. Many gentle slope regions have been transformed into steeply sloped regions. This unknown killer wave causes causalities and mass destruction in the coastal environment due to unaware of tsunami. The shallow waters of bays and estuaries have initiated the seizing. Maximum wave activity observed in the tsunami area closely to that of the bay, low lying areas etc. Initial relief by way of food, clothing, shelter and first-aid medical help has reached most of the affected communities by NGO’s and Government agencies were discussed. The paper also explained the innovative comprehensive long-term rehabilitation program aimed to go beyond basic restoration and rather upgrade standard of living to ensure sustained well-being and prosperity of the tsunami affected people.

A conodont-based revision of the 87Sr/86Sr seawater curve across the Permian-Triassic boundary

Based on analyses of 565 conodonts from Meishan, Liangfengya, and Daijiagou (South China), and Abadeh (central Iran), we propose a revision of the seawater 87Sr/86Sr curve for the time period spanning 200kyr prior to the Permian-Triassic boundary (PTB) to 330kyr after the PTB. With carefully designed sample cleaning, conodonts faithfully record seawater 87Sr/86Sr. Seawater 87Sr/86Sr was 0.707030±10,200kyr prior to the PTB, rose to 0.707070±10 approximately 39kyr prior to the PTB (at the marine extinction horizon, the top of Bed 24e at Meishan), to 0.707080±10 at the PTB, and to 0.707120±20 at 330kyr after the PTB. The rate of change of seawater 87Sr/86Sr was 0.0000185/Myr from the Capitanian minimum to ~100kyr before the PTB, and was 0.00020±7.5/Myr between ~100kyr before and 330kyr after the PTB. Over 6Myr, this rate of change would result in a maximum 87Sr/86Sr of ~0.70825 at the end of the Early Triassic, compared with a model value of ~0.7080. The Sr data are consistent with the interpretation that the rise in marine 87Sr/86Sr was due primarily to an increase in the continental weathering and erosional flux, and that soil-binding vegetation was not re-established during most of the Early Triassic. The rapid rise in seawater 87Sr/86Sr began at least 30kyr prior to the marine extinction at Meishan, indicating that the terrestrial extinction preceded that in the oceans.

Paleogeographic forcing of the strontium isotopic cycle in the Neoproterozoic

The period spanning from 825 to 540Ma is characterized by major changes in the surficial Earth system. This extraordinary interval starts with the breakup of the Rodinia supercontinent and eruption of a series of large igneous provinces and ends with the assembly of Gondwana, giving rise to the Pan-African orogenies. This paleogeographic reorganization is accompanied by a global climatic cooling, including the paroxysmal Cryogenian “snowball” glacial events. The 87Sr/86Sr of seawater displays a major long-term rise over this interval that is punctuated by episodic, smaller declines and inflections. We use a coupled deep time climate-carbon numerical model to explore the complex role of tectonics and climate on this distinct evolution in seawater 87Sr/86Sr. We show that the modulation of the weathering of the erupted large igneous provinces by continental drift explains the changes in seawater 87Sr/86Sr from 800 to 635Ma. The subsequent sharp rise in seawater 87Sr/86Sr from 635 to 580Ma is the result of erosion of radiogenic crust exposed in the Pan-African orogens. Coeval evolution of atmospheric CO2 displays a decrease from about 80 times the pre-industrial level around 800Ma to 5 times just before the beginning of the Phanerozoic.

Thermal growth potential of Atlantic cod by the end of the 21st century.

Ocean warming may lead to smaller body sizes of marine ectotherms, because metabolic rates increase exponentially with temperature while the capacity of the cardiorespiratory system to match enhanced oxygen demands is limited. Here, we explore the impact of rising sea water temperatures on Atlantic cod (Gadus morhua), an economically important fish species. We focus on changes in the temperature-dependent growth potential by a transfer function model combining growth observations with climate model ensemble temperatures. Growth potential is expressed in terms of asymptotic body weight and depends on water temperature. We consider changes between the periods 1985-2004 and 2081-2100, assuming that future sea water temperatures will evolve according to climate projections for IPCC AR5 scenario RCP8.5. Our model projects a response of Atlantic cod to future warming, differentiated according to ocean regions, leading to increases of asymptotic weight in the Barents Sea, while weights are projected to decline at the southern margin of the biogeographic range. Southern spawning areas will disappear due to thermal limitation of spawning stages. These projections match the currently observed biogeographic shifts and the temperature- and oxygen-dependent decline in routine aerobic scope at southern distribution limits.