Kelpwälder vor Südkalifornien trotzen wärmeren Temperaturen

Am 25. Dezember 2016 erschien auf Tichys Einblick der folgende Artikel von Uli Weber:

Der politische Einfluss des WBGU: Die gefährlichen Weissagungen des Papstflüsterers

Alle „Weltrevolutionen“, die einer Bevölkerung durch regulatorische „Top-Down-Strategien“ aufgezwungen worden sind, haben in Unfreiheit, wirtschaftlicher Not und Kriegen bis hin zum Völkermord geendet.

Schon wieder hat es eine Studie des WBGU (Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen) um den Papstflüsterer Professor Schellnhuber nicht in die Schlagzeilen der Tagespresse geschafft. Und schon einmal hatte uns dieser WBGU mit seinem „Gesellschaftsvertrag für eine Große Transformation“ im Jahre 2011 einschneidende planwirtschaftliche „Top-down“-Maßnahmen geweissagt, wie sie mit der „Dekarbonisierung der Welt“ dann vier Jahre später auch prompt eingetreten sind:

Weiterlesen auf Tichys Einblick

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Lange Zeit hatte man gedacht, dass Seetang hochsensibel auf steigende Temperaturen im Ozean reagieren könnte. Eine neue Studie der University of California in Santa Barbara fand nun jedoch Unerwartetes: Der Kelp ist offenbar viel wärmestressresistenter als vermutet. Taucher.net berichtete am 16. Dezember 2016 über die Ergebnisse:

Kelpwälder vor Südkalifornien trotzen wärmeren Temperaturen: Riesentang nicht so empfindlich wie gedacht

Als Anfang 2014 eine Hitzewelle im Pazifik herrschte wurden Wassertemperaturen gemessen, die die höchsten seit Beginn der Aufzeichnungen kurz nach 1900 waren. Forscher der Universität von Kalifornien, Santa Barbara (UCSB) untersuchten den Zustand der riesigen Seetangwälder vor der Küste.

Da der Riesentang eigentlich als empfindlich galt, erwarteten die Forscher, dass er auf die steigenden Temperaturen und die damit zusammenhängenden schlechten Nährstoffbedingungen  reagieren würde. Das war nicht der Fall – der Seetang erwies sich als stabil. Sein Zustand ähnelte dem, den die Forscher bei niedrigeren Wassertemperaturen beobachtet hatten. Die Ergebnisse ihrer Studie wurde vor kurzem in der Zeitschrift Nature Communications veröffentlicht.

Weiterlesen bei Taucher.net

Hier die Originalpressemiteilung der University of California in Santa Barbara vom 13. Dezember 2016:

Kelp Beats the Heat

Using long-term ecological data, marine scientists evaluate the sentinel status of giant kelp during a recent marine heat wave

In early 2014, when a large-scale marine heat wave in the Pacific Ocean produced temperature anomalies greater than anything seen since recordkeeping began in the early 1900s, marine scientists saw something else, too: opportunity. Ocean researchers at UC Santa Barbara quickly seized the chance to evaluate the sentinel status of giant kelp forests along the Southern California coastline as an indicator of climate change. They expected forests of giant kelp (Macrocystis pyrifera), known to be sensitive to such increases as well as to the resulting low-nutrient conditions, to respond quite rapidly to a rise in water temperature. However, to the scientists’ surprise, that was not the case. The kelp, they discovered, was all right. Their findings appear in the journal Nature Communications. “The response that we saw in kelp was really no different than what we’d seen in our temporal record,” explained lead author Daniel Reed, deputy director of UCSB’s Marine Science Institute (MSI). “The values were low but not necessarily lower than what we’d seen during cool-water years.”

Giant kelp does not have the capacity to store nutrients for very long (only about three weeks), and in the absence of new nutrients, the kelp cannot support its rapid growth of about 2 percent per day. The standing biomass — the amount of living kelp present at a given time — is relatively transitory and turns over about seven times a year. “Each frond only lives about three to four months,” Reed said. “So when you have something that grows rapidly and doesn’t live long, you would expect its standing biomass to respond rapidly if it’s subjected to really adverse growing conditions for a long time.”

The researchers used kelp records from a 34-year time series of data taken by Landsat satellites, which — among many other characteristics — measured kelp canopies. The investigators analyzed kelp biomass from Santa Barbara to San Diego through time and related it to sea surface temperatures at those sites. The data showed some large positive temperature anomalies that were unprecedented. For example, in September 2015, the water in the Santa Barbara Channel averaged 4.5 degrees Celsius higher than normal for the entire month. Daily anomalies went as high as 5.5 degrees Celsius. Despite these high temperatures, the team saw no dramatic response by giant kelp whose biomass remained within the range observed during the decades-long time series when the water was cooler. “Nobody knows how this warming event relates to climate change, other than we’ve not seen this before,” said co-author Libe Washburn, an oceanographer at the MSI and a professor in UCSB’s Department of Geography. “That’s somewhat alarming, but this work may provide some insight into how these kelp forests would respond to future climate warming.”

The team also examined changes in understory algae, invertebrates and fishes of the giant kelp ecosystem and found that they didn’t show much of a response to the warming event either. Sea urchins and sea stars were the exception as they declined dramatically due to a disease that was linked to the warm-water event. “The fact that we did not see drastic responses in the rest of the community tells us that we don’t know everything we think we know about this system and about its ecology,” Reed noted. “The results have caused us to pursue lines of research that try to understand how this happens. More importantly, the findings underscore the value of long-term data in terms of trying to tease apart these trends.”

Other UCSB co-authors include Tom Bell, Robert Miller and Shannon Harrer. Andrew Rassweiler of Florida State University also was a contributor. This research was supported by the National Science Foundation’s Long Term Ecological Research program, the NASA Biodiversity and Ecological Forecasting program, the Bureau of Ocean and Energy Management Environmental Studies program and the National Oceanic and Atmospheric Administration in support of the Santa Barbara Channel Marine Biodiversity Observation Network. 

Eine wirklich ermutigende Nachricht. Außer taucher.net blieb die deutschsprachige Presse jedoch stumm. Schweigen im Walde. Offenbar wollte man die Bevölkerung mit den unbequemen Ergebnissen nicht belasten. Ein schönes Beispiel für die selektive Berichterstattung zur Förderung der klimakatastrophalen Ideologie.

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Gute Nachrichten auch aus den hohen nördlichen Breiten. Laut einer neuen Studie von Taejin Park und Kollegen hat sich die Wachstumsperiode dort spürbar verlängert. Außerdem ist die Region ergrünt. Hier die Kurzfassung der Arbeit, die im Juli 2016 in den Environmental Research Letters erschien:

Changes in growing season duration and productivity of northern vegetation inferred from long-term remote sensing data

Monitoring and understanding climate-induced changes in the boreal and arctic vegetation is critical to aid in prognosticating their future. We used a 33 year (1982–2014) long record of satellite observations to robustly assess changes in metrics of growing season (onset: SOS, end: EOS and length: LOS) and seasonal total gross primary productivity. Particular attention was paid to evaluating the accuracy of these metrics by comparing them to multiple independent direct and indirect growing season and productivity measures. These comparisons reveal that the derived metrics capture the spatio-temporal variations and trends with acceptable significance level (generally p < 0.05). We find that LOS has lengthened by 2.60 d dec−1 (p < 0.05) due to an earlier onset of SOS (−1.61 d dec−1, p < 0.05) and a delayed EOS (0.67 d dec−1, p < 0.1) at the circumpolar scale over the past three decades. Relatively greater rates of changes in growing season were observed in Eurasia (EA) and in boreal regions than in North America (NA) and the arctic regions. However, this tendency of earlier SOS and delayed EOS was prominent only during the earlier part of the data record (1982–1999). During the later part (2000–2014), this tendency was reversed, i.e. delayed SOS and earlier EOS. As for seasonal total productivity, we find that 42.0% of northern vegetation shows a statistically significant (p < 0.1) greening trend over the last three decades. This greening translates to a 20.9% gain in productivity since 1982. In contrast, only 2.5% of northern vegetation shows browning, or a 1.2% loss of productivity. These trends in productivity were continuous through the period of record, unlike changes in growing season metrics. Similarly, we find relatively greater increasing rates of productivity in EA and in arctic regions than in NA and the boreal regions. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses of northern vegetation during last three decades.

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Kalte Temperauren sind für Menschen gefährlicher als Hitze. Dies bestätigte erneut eine Studie eines Teams um Antonio Gasparrini, die 2015 in The Lancet erschien. Auszug aus dem Abstract:

Mortality risk attributable to high and low ambient temperature: a multicountry observational study
[...] We analysed 74 225 200 deaths in various periods between 1985 and 2012. In total, 7·71% (95% empirical CI 7·43–7·91) of mortality was attributable to non-optimum temperature in the selected countries within the study period, with substantial differences between countries, ranging from 3·37% (3·06 to 3·63) in Thailand to 11·00% (9·29 to 12·47) in China. The temperature percentile of minimum mortality varied from roughly the 60th percentile in tropical areas to about the 80–90th percentile in temperate regions. More temperature-attributable deaths were caused by cold (7·29%, 7·02–7·49) than by heat (0·42%, 0·39–0·44). Extreme cold and hot temperatures were responsible for 0·86% (0·84–0·87) of total mortality.

Most of the temperature-related mortality burden was attributable to the contribution of cold. The effect of days of extreme temperature was substantially less than that attributable to milder but non-optimum weather. This evidence has important implications for the planning of public-health interventions to minimise the health consequences of adverse temperatures, and for predictions of future effect in climate-change scenarios.

Mit Dank an WUWT.