Archive for August, 2019

Setauket Harbor Task Force takes part in acidification research in Poquott

George Hoffman lowering the Sonde sensor to collect water depth, temperature and salinity readings before taking water samples for alkalinity. Photo by Maria Hoffman

A local task force recently took part in a vital water testing project and chose the Village of Poquott to accomplish its task.

George Hoffman, co-founder of Setauket Harbor Task Force, said the organization participated in Shell Day Aug. 22 when the group tested water from the Village of Poquott’s new dock. Shell Day is a six-state water monitoring event coordinated by Northeast Coastal Acidification Network. NECAN, which serves as an interface between research and industry interests, enlisted 50 water quality groups run by citizen scientists to test for levels of ocean acidification along the harbors and bays from Maine to the Long Island Sound.

Covering more than 600 miles of the U.S. Northeast coast, the testing will give scientists a broader picture of the extent of acidification that comes into the ocean from harbors and bays.

Continue reading ‘Setauket Harbor Task Force takes part in acidification research in Poquott’

Seasonal changes in carbonate saturation state and air‐sea CO2 fluxes during an annual cycle in a stratified‐temperate fjord (Reloncaví Fjord, Chilean Patagonia)

Changes may be occurring in the carbonate chemistry of fjords due to natural and anthropogenic disturbance of major freshwater sources. We present a high frequency time series study of seasonal pH and CO2 partial pressure (pCO2) in a north Patagonian fjord with a focus on changes in freshwater inflows and biological processes. To do this, we monitored pH and pCO2 in situ, along with river streamflow, salinity, temperature, and dissolved oxygen (DO) in the Reloncaví Fjord (41.5°S) for a full year (January to December 2015). Strong seasonal variability was observed in the pCO2, pH and DO of the fjord’s surface waters. During the summer, pCO2 reached its annual minimum (range: 187‐571 μatm) and pH its maximum (range: 7.98‐8.24), coinciding with lower freshwater inflows (204‐307 m3 s‐1) and high DO (280‐378 μmol kg‐1), as well as aragonite saturation states (ΩArag) higher than 1. In contrast, in winter, pCO2 ranged from 461‐1008 μatm and pH from 7.57‐8.03, coinciding with high freshwater inflows (1049‐1402 m3 s‐1), lower oxygen (216‐348 μmol kg‐1) and constant under‐saturation of ΩArag. Reloncaví Fjord had an annual air‐water CO2 flux of 0.716 ± 2.54 mol m‐2 yr‐1 during 2015, and thus acted as a low emission system. The annual cycle was mainly governed by seasonal changes in biological processes that enhanced the shift from a CO2 sink in late spring and summer, caused by high primary production rates, to a CO2 source during the rest of the year caused by high community respiration due to allochthonous organic carbon inputs.

Continue reading ‘Seasonal changes in carbonate saturation state and air‐sea CO2 fluxes during an annual cycle in a stratified‐temperate fjord (Reloncaví Fjord, Chilean Patagonia)’

Carbon dioxide, shell building, and ocean acidification

To build shells and skeletons, marine organisms, such as this hypothetical clam, extract calcium ions and carbonate ions from seawater, combining them into solid crystals of calcium carbonate that are laid down to make shells.

Continue reading ‘Carbon dioxide, shell building, and ocean acidification’

Positive genetic associations among fitness traits support evolvability of a reef‐building coral under multiple stressors

Climate change threatens organisms in a variety of interactive ways that requires simultaneous adaptation of multiple traits. Predicting evolutionary responses requires an understanding of the potential for interactions among stressors and the genetic variance and covariance among fitness‐related traits that may reinforce or constrain an adaptive response. Here we investigate the capacity of Acropora millepora, a reef‐building coral, to adapt to multiple environmental stressors: rising sea surface temperature, ocean acidification, and increased prevalence of infectious diseases. We measured growth rates (weight gain), coral color (a proxy for Symbiodiniaceae density), and survival, in addition to nine physiological indicators of coral and algal health in 40 coral genets exposed to each of these three stressors singly and combined. Individual stressors resulted in predicted responses (e.g., corals developed lesions after bacterial challenge and bleached under thermal stress). However, corals did not suffer substantially more when all three stressors were combined. Nor were trade‐offs observed between tolerances to different stressors; instead, individuals performing well under one stressor also tended to perform well under every other stressor. An analysis of genetic correlations between traits revealed positive covariances, suggesting that selection to multiple stressors will reinforce rather than constrain the simultaneous evolution of traits related to holobiont health (e.g., weight gain and algal density). These findings support the potential for rapid coral adaptation under climate change and emphasize the importance of accounting for corals’ adaptive capacity when predicting the future of coral reefs.

Continue reading ‘Positive genetic associations among fitness traits support evolvability of a reef‐building coral under multiple stressors’

Heterotrophy of oceanic particulate organic matter elevates net ecosystem calcification

Coral reef calcification is expected to decline due to climate change stressors such as ocean acidification and warming. Projections of future coral reef health are based on our understanding of the environmental drivers that affect calcification and dissolution. One such driver that may impact coral reef health is heterotrophy of oceanic‐sourced particulate organic matter, but its link to calcification has not been directly investigated in the field. In this study, we estimated net ecosystem calcification (NEC) and oceanic particulate organic carbon (POCoc) uptake across the Kāneʻohe Bay barrier reef in Hawai‘i. We show that higher rates of POCoc uptake correspond to greater NEC rates, even under low aragonite saturation states (Ωar). Hence, reductions in offshore productivity may negatively impact coral reefs by decreasing the food supply required to sustain calcification. Alternatively, coral reefs that receive ample inputs of POCoc may maintain higher calcification rates, despite a global decline in Ωar.

Continue reading ‘Heterotrophy of oceanic particulate organic matter elevates net ecosystem calcification’

CO2 effects on diatoms: a synthesis of more than a decade of ocean acidification experiments with natural communities (update)

Diatoms account for up to 50 % of marine primary production and are considered to be key players in the biological carbon pump. Ocean acidification (OA) is expected to affect diatoms primarily by changing the availability of CO2 as a substrate for photosynthesis or through altered ecological interactions within the marine food web. Yet, there is little consensus how entire diatom communities will respond to increasing CO2. To address this question, we synthesized the literature from over a decade of OA-experiments with natural diatom communities to uncover the following: (1) if and how bulk diatom communities respond to elevated CO2 with respect to abundance or biomass and (2) if shifts within the diatom communities could be expected and how they are expressed with respect to taxonomic affiliation and size structure. We found that bulk diatom communities responded to high CO2 in ∼60 % of the experiments and in this case more often positively (56 %) than negatively (32 %) (12 % did not report the direction of change). Shifts among different diatom species were observed in 65 % of the experiments. Our synthesis supports the hypothesis that high CO2 particularly favours larger species as 12 out of 13 experiments which investigated cell size found a shift towards larger species. Unravelling winners and losers with respect to taxonomic affiliation was difficult due to a limited database. The OA-induced changes in diatom competitiveness and assemblage structure may alter key ecosystem services due to the pivotal role diatoms play in trophic transfer and biogeochemical cycles.

Continue reading ‘CO2 effects on diatoms: a synthesis of more than a decade of ocean acidification experiments with natural communities (update)’

BRLT participates in multi-state “Shell Day” coastal water monitoring effort

On Aug. 22, Boothbay Region Land Trust (BRLT) took a new step in its efforts to provide sustained monitoring of coastal waters in the Boothbay region by participating in the first ever “Shell Day.” Shell Day is a single-day coastal monitoring blitz organized by the Northeast Coastal Acidification Network (NECAN) and spanning shores from Long Island Sound to Downeast Maine. The initiative, whose name evokes the particular threat that shellfish face from increasing ocean acidity, aims to generate a snapshot of coastal conditions along the northeast.

BRLT Coastal Water Monitoring Program Coordinator and volunteer, Ed Green, helped to collect the two samples from off of Newagen and the Damariscotta River that were part of this multi-state sampling effort. “This is the first coordinated Citizen Science effort to measure our coastal waters for the impact of ocean acidification” Green notes. “We at the BRLT are proud and excited to be a contributor to this inaugural effort!”

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(Re)framing ocean acidification in the context of the United Nations Framework Convention on climate change (UNFCCC) and Paris Agreement

Ocean acidification is most frequently framed by the scientific community as a concurrent threat to climate change, rather than an effect of it. This separation of the two phenomena has long been deemed as a way of garnering heightened policy attention for ocean acidification rather than having it bound up in the often contested politics of climate change. This effort, however, appears to have resulted in the inadvertent placing of ocean acidification outside of the mandate of the United Nations Framework Convention on Climate Change (UNFCCC). This has created a significant gap in the global governance of this issue with no multilateral agreement understood as having jurisdiction over the mitigation of rising ocean acidity. For these reasons this paper argues that an alternative framing of ocean acidification as an effect of climate change is warranted. This would include ocean acidification in the core obligations of the Convention, thereby filling the mitigation governance gap and avoiding perverse implementation outcomes. It is contended that interpreting the UNFCCC in this way is more consistent with its objective and purpose than the existing interpretations that place ocean acidification beyond the remit of the Convention.

Continue reading ‘(Re)framing ocean acidification in the context of the United Nations Framework Convention on climate change (UNFCCC) and Paris Agreement’

Scientists’ warning to humanity: microorganisms and climate change

In the Anthropocene, in which we now live, climate change is impacting most life on Earth. Microorganisms support the existence of all higher trophic life forms. To understand how humans and other life forms on Earth (including those we are yet to discover) can withstand anthropogenic climate change, it is vital to incorporate knowledge of the microbial ‘unseen majority’. We must learn not just how microorganisms affect climate change (including production and consumption of greenhouse gases) but also how they will be affected by climate change and other human activities. This Consensus Statement documents the central role and global importance of microorganisms in climate change biology. It also puts humanity on notice that the impact of climate change will depend heavily on responses of microorganisms, which are essential for achieving an environmentally sustainable future.

Continue reading ‘Scientists’ warning to humanity: microorganisms and climate change’

The mass impacts on chemosynthetic primary producers: potential implications on anammox communities and their consequences

The potential of a mass asteroid impact on Earth to disturb the chemosynthetic communities at global scale is discussed. Special emphasis is made on the potential influence on anammox communities and their implications in the nitrogen biogeochemical cycle. According to our preliminary estimates, anammox communities could be seriously affected as a consequence of global cooling and the large process of acidification usually associated with the occurrence of this kind of event. The scale of affectations could vary in a scenario like the Chicxulub as a function of the amount of soot, depth of the water column and the deposition rate for sulphates assumed in each case. The most severe affectations take place where the amount of soot and sulphates produced during the event is higher and the scale of time of settlements for sulphates is short, of the order of 10 h. In this extreme case, the activity of anammox is considerably reduced, a condition that may persist for several years after the impact. Furthermore, the impact of high levels of other chemical compounds like sulphates and nitrates associated with the occurrence of this kind of event are also discussed.

Continue reading ‘The mass impacts on chemosynthetic primary producers: potential implications on anammox communities and their consequences’


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