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Ocean acidification (OA) will decrease shellfish growth and survival, with ecological and economic consequences for fisheries and aquaculture. However, the high variability of results among experiments, and the lack of long-term studies, make it difficult to predict the effect that OA will have on bivalve species. We tested the long-term effect of high CO2 on growth, calcification rates, and survival of juveniles of the commercial bivalve species Chamelea gallina from Southern Portugal. The local high alkalinity of seawater probably buffered the negative effect of the pH drop, and after 75 days juveniles increased their growth and calcification rates with CO2. However, after 217 days, the situation reversed, bivalves under control conditions had the highest growth and calcification rates, while individuals under high CO2 presented negative calcification rates. The biometric variable that responded first was the width of the individuals, followed by the height and length of the shells. Survival was unaffected except for a mortality peak of juveniles under control and intermediate conditions as a consequence of a temperature drop. In the short term, C. gallina will increase their calcification rates to compensate for OA. However, in the long term, the additional energy expended will be translated into growth losses with negative repercussions for the fisheries and aquaculture. The cultivation of shellfish on high alkaline seawater should be further explored as a bioremediation measure to mitigate the negative effect of OA on shellfish aquaculture. [ABSTRACT FROM AUTHOR]

The combination of ocean acidification (OA) and global warming is expected to have a significant effect on the diversity and functioning of marine ecosystems, particularly on calcifying algae such as rhodoliths (maërl) that form extensive beds worldwide, from polar to tropical regions. In addition, the increasing frequency of extreme events, such as heat waves, threatens coastal ecosystems and may affect their capacity to fix blue carbon. The few studies where the simultaneous effects of both temperature and CO2 were investigated have revealed contradictory results. To assess the effect that high temperature spells can have on the maërl beds under OA, we tested the short‐time effects of temperature and CO2 on the net photosynthesis, respiration, and calcification of the recently described species Phymatolithon lusitanicum, the most common maërl species of southern Portugal. Photosynthesis, calcification, and respiration increased with temperature, and the differences among treatments were enhanced under high CO2. We found that in the short term, the metabolic rates of Phymatolithon lusitanicum will increase with CO2 and temperature as will the coupling between calcification and photosynthesis. However, under high CO2, this coupling will favor photosynthesis over calcification, which, in the long term, can have a negative effect on the blue carbon fixing capacity of the maërl beds from southern Portugal. [ABSTRACT FROM AUTHOR]

Abstract: Mäerl/rhodolith beds are protected habitats that may be affected by ocean acidification (OA), but it is still unclear how the availability of CO2 will affect the metabolism of these organisms. Some of the inconsistencies found among OA experimental studies may be related to experimental exposure time and synergetic effects with other stressors. Here, we investigated the long‐term (up to 20 months) effects of OA on the production and calcification of the most common mäerl species of southern Portugal, Phymatolithon lusitanicum. Both the photosynthetic and calcification rates increased with CO2 after the first 11 months of the experiment, whereas respiration slightly decreased with CO2. After 20 months, the pattern was reversed. Acidified algae showed lower photosynthetic and calcification rates, as well as lower accumulated growth than control algae, suggesting that a metabolic threshold was exceeded. Our results indicate that long‐term exposure to high CO2 will decrease the resilience of Phymatolithon lusitanicum. Our results also show that shallow communities of these rhodoliths may be particularly at risk, while deeper rhodolith beds may become ocean acidification refuges for this biological community. [ABSTRACT FROM AUTHOR]

Meadows of Halodule wrightii (Cymodoceaceae) underwent a decline in a tidal flat located at Paranaguá Bay (Parana, SE Brazil). This decline appeared to be related to an overgrowth of the epiphytic macroalga Hincksia mitchelliae (Harv.) P. C. Silva (Phaeophyceae). In order to characterize the type of epiphytism between the alga and its plant host, we compared two samples from the beginning and end of the algal overgrowth via electron and optical microscopes. The investigation revealed that at both sampling periods, there was an epiphytism of type II, which is due to an infection of epiphytes strongly attached to the surface of the host but not associated to any apparent direct host-tissue damage. The presence of plasmodesmata between the cells of Hincksia only in the late stage of the host-epiphyte interaction indicated a change in the vegetative organization of Hincksia in relation to its host to improve nutrient absorption and distribution through the epiphyte cells. This is the first report on plasmodesmata in H. mitchelliae. The proposed mechanisms with which the algal epiphytes lead seagrasses to death are shadowing by adhesion on Halodule surface and disruption of its osmoregulatory system. Our findings have implications for the conservation and management strategies of seagrass ecosystems. [ABSTRACT FROM AUTHOR]

Meadows of the seagrass Halodule wrightii occur on shallow subtidal sandy bottoms of euhaline high-energy sites in Paranaguá Bay, Brazil. Close to their southernmost limit in the South Atlantic, local populations are patchy, unstable and most often do not reproduce sexually. We describe morphological and biomass variations of a local H. wrightii meadow off Rasa da Cotinga Island, which deteriorated from a healthy state to subsequently decline and die-off. Leaf width and length, number of leaves per shoot, leaf sheath length, rhizome width, internodal length and biomass, sediment grain size, CaCO3 and POM contents were measured on six sampling dates between November 2004 and October 2005. Compared to other Halodule meadows along the southwestern Atlantic coastline, local plants had shorter and narrower leaves, shorter leaf sheaths, thinner rhizomes, fewer leaves per shoot, a larger internodal distance, and lower biomass. Local variations in morphology and plant biomass followed a seasonal pattern, but were affected by stressor, such as the lowering of temperature, precipitation, and high turbidity associated with southwesterly winds that increased meadow vulnerability. Life history traits of H. wrightii, a short-lived species with rapid growth and ability to reproduce vegetatively under stress conditions, promote resilience and rapid recovery of local meadows, which exhibit a typically fugitive behavior. [ABSTRACT FROM AUTHOR]

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The combination of ocean acidification (OA) and global warming is expected to have a significant effect on the diversity and functioning of marine ecosystems, particularly on calcifying algae such as rhodoliths (maërl) that form extensive beds worldwide, from polar to tropical regions. In addition, the increasing frequency of extreme events, such as heat waves, threatens coastal ecosystems and may affect their capacity to fix blue carbon. The few studies where the simultaneous effects of both temperature and CO 2 were investigated have revealed contradictory results. To assess the effect that high temperature spells can have on the maërl beds under OA, we tested the short-time effects of temperature and CO 2 on the net photosynthesis, respiration, and calcification of the recently described species Phymatolithon lusitanicum , the most common maërl species of southern Portugal. Photosynthesis, calcification, and respiration increased with temperature, and the differences among treatments were enhanced under high CO 2 . We found that in the short term, the metabolic rates of Phymatolithon lusitanicum will increase with CO 2 and temperature as will the coupling between calcification and photosynthesis. However, under high CO 2 , this coupling will favor photosynthesis over calcification, which, in the long term, can have a negative effect on the blue carbon fixing capacity of the maërl beds from southern Portugal., Competing Interests: None declared., (© 2019 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Mäerl/rhodolith beds are protected habitats that may be affected by ocean acidification (OA), but it is still unclear how the availability of CO 2 will affect the metabolism of these organisms. Some of the inconsistencies found among OA experimental studies may be related to experimental exposure time and synergetic effects with other stressors. Here, we investigated the long-term (up to 20 months) effects of OA on the production and calcification of the most common mäerl species of southern Portugal, Phymatolithon lusitanicum . Both the photosynthetic and calcification rates increased with CO 2 after the first 11 months of the experiment, whereas respiration slightly decreased with CO 2 . After 20 months, the pattern was reversed. Acidified algae showed lower photosynthetic and calcification rates, as well as lower accumulated growth than control algae, suggesting that a metabolic threshold was exceeded. Our results indicate that long-term exposure to high CO 2 will decrease the resilience of Phymatolithon lusitanicum . Our results also show that shallow communities of these rhodoliths may be particularly at risk, while deeper rhodolith beds may become ocean acidification refuges for this biological community.

Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO 2 . However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and p CO 2 . Here we describe a system in which the target p CO 2 is controlled via direct analysis of p CO 2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures p CO 2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO 2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of p CO 2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum . We found that after 11 months of high CO 2 exposure, photosynthesis increased with CO 2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO 2 , such as temperature, irradiance and nutrients., Competing Interests: The authors declare that they have no competing interests.

Familial partial lipodystrophy (FPL) type 1 is a syndrome characterized by loss of subcutaneous fat in arms and legs and an excess of body fat in face, neck, and torso. This rare syndrome is usually diagnosed when patients present cardiovascular complications or pancreatitis due to the severe metabolic abnormalities. Here we present the case of a 45 year old diabetic female without any pathological family history, a poor glycemic control (HbA1c 11.7%), hypertriglideridemia (3000 mg/dl), a body mass index (BMI) of 38, thin limbs, subcutaneous fat loss in gluteal area and ledge of fat above them, prominent veins in lower extremities, moon face, and acanthosis nigricans; as well as hypertension (150/100 mmHg) and subcutaneous folds measuring less than average were observed. Hypercortisolism was discarded and leptin levels were measured (16.8 mg/ml, VR: BMI > 30: 50 mg/ml). Due to these clinical and biochemical manifestations, and low leptin levels (16.8 mg/ml), Kobberling syndrome was suspected; however, LMNA mutation analysis was negative. Changes in lifestyle and treatment with fenofibrate, biphasic insulin 50/50, and enalapril were initiated showing a a significant metabolic improvement: HbA1c (7.8%) and TG (243 mg/dl). FPL type 1 is a familial disease, although there are spontaneous cases. No specific mutation is responsible for this syndrome. Due to its clinical manifestations, Cushing syndrome must be discarded.