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Showing posts with label DEAD ZONE(ecology). Show all posts
Showing posts with label DEAD ZONE(ecology). Show all posts

Three new species of saddled loricariid catfishes, and a review of Hemiancistrus, Peckoltia, and allied genera (Siluriformes)

Written By Unknown on Tuesday, February 3, 2015 | 6:53 PM

(Figs 2–4). CORBIDI 14685, an adult male (Figs 2–4) from 13.5806 S, 75.2449 W (WGS84), Chicchobamba, upstream of Represa Negrayccassa, upper drainage of the Huaytará river, 3900 m, Provincia Huaytará, Región Huancavelica, Peru, collected by A. Catenazzi, V. Vargas García, and M. Jaico Huayanay

We describe a new species of Telmatobius from the Pacific slopes of the Andes in central Peru. Specimens were collected at 3900 m elevation near Huaytará, Huancavelica, in the upper drainage of the Pisco river. The new species has a snout–vent length of 52.5 ± 1.1 mm (49.3–55.7 mm, n = 6) in adult females, and 48.5 mm in the single adult male. The new species has bright yellow and orange coloration ventrally and is readily distinguished from all other central Peruvian Andean species of Telmatobius but T. intermedius by having vomerine teeth but lacking premaxillary and maxillary teeth, and by its slender body shape and long legs. The new species differs from T. intermedius by its larger size, flatter head, and the absence of cutaneous keratinized spicules (present even in immature females of T. intermedius), and in males by the presence of minute, densely packed nuptial spines on dorsal and medial surfaces of thumbs (large, sparsely packed nuptial spines in T. intermedius). The hyper-arid coastal valleys of Peru generally support low species richness, particularly for groups such as aquatic breeding amphibians. The discovery of a new species in this environment, and along a major highway crossing the Andes, shows that much remains to be done to document amphibian diversity in Peru.

The Tropical Andes are characterized by a large diversification of the aquatic frogs of the genus Telmatobius Wiegmann, 1834. Sixty-two species are currently recognized in this genus (AmphibiaWeb 2014; Aguilar and Valencia 2009; Frost 2014; including species previously assigned to Batrachophrynus Peters, 1873). The altitudinal distribution of Telmatobius ranges from 1000 m to 5400 m (De la Riva and Harvey 2003; Seimon et al. 2007), and its longitudinal distribution extends from the equator (T. niger Barbour & Noble, 1920, whose populations have been extirpated in Ecuador; Merino-Viteri et al. 2005) to 29°S, on the eastern slopes of the Argentinean Andes (T. contrerasi Cei, 1977). Twenty-eight species of Telmatobius are distributed in Peru (Lehr 2005; AmphibiaWeb 2014), but of these only five [T. arequipensis Vellard, 1955; T. intermedius Vellard, 1955; T. jelskii (Peters, 1873); T. peruvianus Wiegmann, 1834; T. rimac Schmidt, 1954] are known to occur in the hyper-arid coastal valleys that drain directly into the Pacific Ocean.

During October 2012 we made several surveys for the Biodiversity and Monitoring Assessment Program of the Smithsonian Conservation Biology Institute’s Center for Conservation Education and Sustainability (Catenazzi et al. 2013a; Catenazzi et al. 2013b). During one of these surveys, we found a population of Telmatobius in the upper drainage of the Huaytará river (Region of Huancavelica), a tributary of the Pisco river in the Pacific slopes of the central Peruvian Andes. Individuals of this population possess traits that do not correspond to the morphological characteristics of other species found in the arid coastal valleys of central Peru (Fig. 1), namely T. rimac to the north and T. intermedius to the south (Vellard 1951; Schmidt 1954; Lehr 2005). Therefore, here we describe the new species and provide a diagnosis to differentiate it from congeneric forms.

Source: Read Full Artical at - zookeys

New study finds Alaskans familiar with ocean acidification, not aware of risks to fisheries

New research published in Marine Policy from the first Alaska-focused study on public understanding and awareness of ocean acidification risk shows that Alaskans are three times more aware of ocean acidification than Americans in general.  However, Alaskans have difficulty seeing ocean acidification as an immediate risk, and the direct risks to Alaska’s fisheries are still not well understood. The research, “Gauging perceptions of ocean acidification in Alaska,” can be read online.

In Alaska, the impacts of ocean acidification have the potential to be even worse than “other coastal communities because of an accelerated rate of change in ocean chemistry, and statewide reliance on commercial and subsistence fishing. Accurately evaluating ocean acidification risk directly influences the ability to respond to change. The research builds on earlier NOAA-led research showing that communities in southeast and southwest Alaska are more at risk than other areas of the state because of their heavy reliance on fisheries expected to be impacted by ocean acidification.

“We wanted to learn the best way to provide Alaskans with the information they need to properly respond to ocean acidification,” said Lauren Frisch, who led the study and is a research associate at the University of Alaska Fairbanks Ocean Acidification Research Center. “The first step was to determine where there are gaps in the understanding of ocean acidification so that we can then work to fill them in.”
                      Crab fishing
A new study shows that Alaskans know about ocean acidification, but are not aware of the risk it poses to Alaskan fisheries. (NOAA)

Some 2000 Alaskans received a questionnaire in September, 2013. Questionnaires asked about each respondent’s role in the state's fishing industry as well as their belief in, understanding of, and concern about ocean acidification. The questionnaire’s response rate was 18 percent, which is high for studies of this nature. Results showed limited understanding of how Alaska will be uniquely impacted by ocean acidification. For example, only 28 percent of Alaskans believe that ocean acidification would have a greater impact on Alaska than other states in the United States.  Alaskans affiliated with the state’s fishing industry are not significantly more concerned about ocean acidification than those unaffiliated, and only 33 percent believe that ocean acidification will decrease revenue for fisheries. Finally, ocean acidification is perceived as a distant risk.  

“It can be difficult to think about ocean acidification as an immediate risk with all of the other challenges that we’re facing,” said Jeremy Mathis, who is the co-lead author on the paper describing the study’s results and an oceanographer at NOAA’s Pacific Marine Environmental Laboratory. “We really have to work harder to get the message out to stakeholders around Alaska that ocean acidification is something that they need to consider sooner rather than later.”

With a better idea of what Alaskans understand about this issue, the next step is to shape public education in a way that facilitates a long-term discussion of ocean acidification drivers and impacts, as well as mitigation and adaptation strategies.

“Moving forward, we need to figure out how to enhance this understanding that acidification is not uniform, and therefore adaptation plans will be more successful if they are local.  Educating communities with local examples about their specific risk could help foster this understanding.  The best thing we can do is provide vulnerable communities the toolset to evaluate risk themselves,” said Frisch.

Source: NOAA

Satellites for peat sake - Peatlands play vital role in curbing climate change

Written By Unknown on Monday, February 2, 2015 | 2:34 AM

                         Peatlands play vital role in curbing climate change Credit: JHU
Peatlands make up just 3% of land but capture twice as much carbon as all forests combined.

They are also an important source of drinking water and provide a home to many rare and threatened animals and plants.

Ecosystems work best when left intact but these wetland areas are being threatened by human exploitation, resulting in vast carbon emissions, frequent and uncontrollable fires and loss of valuable landscapes.
                                            Handheld devices for collecting ground data

Rezatec in Oxfordshire, UK, supported by ESA’s Integrated Applications Promotions programme, in the Peat spotter project will give landowners an easier and cheaper way of calculating the potential economic value of conserving or restoring their peatlands and monitoring the results of their investment.

“Peat spotter helps landowners to manage their peat resource more sustainably through mapping the area, measuring the carbon it contains and monitoring how its integrity is changing over time,” says Patrick Newton, CEO of Rezatec.

To do this, satellite imagery is used to locate and create initial mappings of peatlands. This information is enriched with ground data collected by field agents using handheld devices.

An app prompts users in the field for measurements, satnav adds location information, and the data are then sent directly to a centralised office via satcom for analysis.

The new approach is a cost-effective way of measuring peat extent and how intact it is over wide and potentially remote areas that are otherwise expensive to measure or inaccessible from the ground.

Rezatec expects water companies, conservation groups and those using typically state-owned land for uses such as plantations to sign up for this service.

Peatlands are an important source of drinking water. Water companies using these resources can significantly reduce the water treatment necessary to meet drinking water standards if they are able to identify areas of degraded peatland and make restoration efforts at source.

Water derived from degraded peatlands can contain raised levels of dissolved organic carbon causing significant discolouration.

On land that is typically used for plantations, peat assets are included in the measurement of the greenhouse gas balance, but only through a rough calculation.

                                                     Deforestation damages peatlands

Making it cheaper and easier to locate and monitor peatlands will make it simpler to calculate the economic value of conserving and restoring these areas and, in turn, this can be positive for society, the economy and the environment.

Within the mobile device apps Rezatec includes: guides to help identify flora and fauna, videocam monitoring of borders, photo uploading, alerts when levels are breached, and fire mapping.

“This innovative use of satellite data has far-reaching benefits for the space industry and the wider UK economy,” notes Alan Brunstrom, head of the Service Business Office in ESA’s Integrated Applications Promotion programme.

“Perhaps more importantly, it demonstrates how the scientific analysis of ‘big data’ can benefit the environment and, in this particular scenario, provide valuable information to allow sustainable peatland management practices on a global scale.”

Source: JHU

Trade winds ventilate the tropical oceans: Explanation for increasing oxygen deficiency

Written By Unknown on Monday, December 22, 2014 | 1:49 AM

Scheme of the tropical Pacific: Strong growth of plankton (1) leads to a high oxygen consumption and extended oxygen minimum zones (2). Ocean currents (3) at a few hundred meters depth provide an influx of oxygenated water from the subtropics (4). Fluctuations of the trade winds (5) influence the strength of these currents. Credit: Graphics: Claus Böning, Markus Scheinert, GEOMAR
Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Collaborative Research Centre 754 "Climate -- Biogeochemical Interactions in the Tropical Ocean" have found an explanation with the help of model simulations: a natural fluctuation of the trade winds. The study has been published in the international journal Geophysical Research Letters.

The changes can be measured, but their reasons were unknown. For several decades, scientists have carefully observed that the oxygen minimum zones (OMZ) in the tropical oceans are expanding. These zones are a paradise for some specially adapted microorganisms, but for all larger marine organisms such as fish and marine mammals they are uninhabitable. Thus, their expansion has already narrowed down the habitat of some fish species.

Marine scientists from the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Kiel Collaborative Research Centre (Sonderforschungsbereich, SFB) 754 "Climate -- Biogeochemical Interactions in the Tropical Ocean" now have found a possible reason for these changes by using a model simulation of climate and biological processes. As their study shows, the trade winds north and south of the Equator play a crucial role in the supply of oxygen to tropical sea water. "So fluctuations in the trade winds could also be responsible for the observed enlargement of the oxygen minimum zones in recent years," explains Dr. Olaf Duteil, lead author of the study, which has now been published in the international journal Geophysical Research Letters.

OMZs exist in different intensities at the eastern edges of all tropical oceans. Because nutrient-rich water from the depths reaches the surface in these areas plankton thrives particularly well. Therefore large amounts of plankton organisms die there, too. After their death they sink down to the ocean floor. On the way down bacteria start to decompose the biomass. In doing so they consume the oxygen. The largest of these OMZs stretches from the coasts of Chile and Peru far into the Pacific ocean.

At the same time currents at a few hundred meters depth transport oxygen-rich water from the subtropics towards the tropics, where the oxygen minimum zones lie. "One can think of the tropical Pacific Ocean as a bathtub. When I open the tap, I fill the bathtub with water or 'oxygen', respectively. When the siphon is open, too, we lose oxygen at the same time. We then have an instable equilibrium between input and output," explains Dr. Duteil, "If I turn off the tap a little, the tub empties slowly."

As the researchers were able to determine in a computer simulation of the oxygen balance now, the strength of the currents and thus the oxygen flow to the tropics is directly related to the strength of the trade winds. "It is well known that they vary on a decadal time scale," says co-author Prof. Dr. Claus Böning from GEOMAR, "but these variations haven never been investigated in relation to the oxygen budget of tropical oceans. "

Since the trade winds have been in a weak phase since the mid-1970s, this could be the explanation for the observed enlargement of the oxygen minimum zones. "The oxygen bathtub of the tropical oceans is emptying," says Dr. Duteil. Once the trade winds come back into a stronger phase, the process will be reversed.

This does not mean that external processes such as the general global warming have no influence on the oxygen concentrations in the tropical oceans. "There is evidence that global change affects the major wind systems of the Earth. That would have a direct impact on the oxygen transport in the subtropical and tropical ocean," explains Prof. Andreas Oschlies, co-author and speaker of the SFB 754. "But it is important that according to this study the trade winds in any case as must be considered as a factor for long-term development of tropical oxygen minimum zones," Oschlies adds.

Source: Helmholtz Centre for Ocean Research Kiel (GEOMAR)

'Aquatic osteoporosis' jellifying lakes

Written By Unknown on Thursday, December 18, 2014 | 4:53 AM

A handful of Holopedium capsules which are replacing the water flea Daphnia due to declining calcium levels in many lakes.
Credit: Image courtesy of Queen's University
A plague of "aquatic osteoporosis" is spreading throughout many North American soft-water lakes due to declining calcium levels in the water and hindering the survival of some organisms, says new research from Queen's University.

Researchers from Queen's, working with colleagues from York University and the University of Cambridge, as well as other collaborators, have identified a biological shift in many temperate, soft-water lakes in response to declining calcium levels after prolonged periods of acid rain and timber harvesting. The reduced calcium availability is hindering the survival of aquatic organisms with high calcium requirements and promoting the growth of nutrient-poor, jelly-clad animals.

In the study, researchers looked at the microscopic organisms (~1 mm) Daphnia and Holopedium -- the latter whose size is greatly increased by its jelly capsule.

"Calcium is an essential nutrient for many lake-dwelling organisms, but concentrations have fallen so low in many lakes that keystone species can no longer survive," says Adam Jeziorski, one of the lead authors of the study and a postdoctoral fellow in the Department of Biology at Queen's.

The research team found that when calcium levels are low, the water flea Daphnia, which has high calcium requirements, becomes less abundant. Importantly, this keystone species is being replaced by its jelly-clad competitor, Holopedium.

"Conditions now favour animals better adapted to lower calcium levels, and these changes can have significant ecological and environmental repercussions," says Dr. Jeziorski.

Tiny fossils from lake sediments were studied to determine the pre-impact conditions of the lakes as the calcium decline began before monitoring programs were in place. Using this technique, the team was able to examine the environmental trends from the past approximately 150 years.
"Lake sediments act like a history book of past changes in a lake, recording what happened before the problem was identified," says John Smol (Biology), Canada Research Chair in Environmental Change. "Jelly-clad invertebrates have been increasing in an alarming number of lakes. This is likely a long-term effect of acid rain on forest soils, logging and forest regrowth."
The increase in jelly-clad invertebrates can have important implications for lake biology, altering food webs, but can also clog water intakes.

"Many lakes we investigated have passed critical thresholds," says Dr. Smol. "We have been reduced to the role of spectator as these changes continue to unfold. Once again we see there are many unexpected consequences of our actions, most of which are negative."

This research was funded by the Natural Sciences and Engineering Research Council of Canada and the Ontario Ministry of the Environment and Climate Change.
The study is published in Proceedings of the Royal Society B.

SourceQueen's University

Abundance of microplastics in the world's deep seas

Written By Unknown on Tuesday, December 16, 2014 | 9:29 PM

Richard Thompson.
Credit: Image courtesy of University of Plymouth
The deep sea is becoming a collecting ground for plastic waste, according to research led by scientists from Plymouth University and Natural History Museum.

The new study, published today in Royal Society Open Science, reveals around four billion microscopic plastic fibres could be littering each square kilometre of deep sea sediment around the world.

Marine plastic debris is a global problem, affecting wildlife, tourism and shipping. Yet monitoring over the past decades has not seen its concentration increase at the sea surface or along shorelines, despite experts knowing that more is being created.

However, the current study indicates this may be because microplastics have sunk to the ocean floor, with the number of fibres recorded in the deep seas up to four times greater than in shallow and coastal waters.

"The puzzle for marine scientists has been to establish where plastic debris is going. Part of the answer is that much of this waste is breaking down into fibres invisible to the naked eye and sinking to the sea floor," said Dr Lucy Woodall, zoologist at the Natural History Museum. "It is alarming to find such high levels of contamination, especially when the full effect of these plastics on the delicate balance of deep sea ecosystems is unknown."

The study, which also involved the University of Barcelona, the University of Oxford and the Scottish Association for Marine Science, focussed on deep-sea sediment and coral samples collected by Dr Woodall and other scientists from 16 sites in the Mediterranean Sea, Atlantic and Indian Oceans.

Analysis of the non-natural particles at Plymouth University confirmed microplastics were abundant in all the samples (ranging from 1.4-40 pieces per 50ml of sediment), were commonly around 2-3mm in length and were mostly blue, black, green or red in colour.
Rayon -- a humanmade non-plastic polymer used in personal hygiene products and clothing -- contributed to 56.9% of the total fibres seen, with polyester, polyamides, acetate and acrylic among the others recorded.

Professor Richard Thompson, Professor of Marine Biology at Plymouth University, coordinated the study and led the identification process. He said: "The deep sea habitat extends to more than 300 million km² globally, so the discovery of previously under-reported microplastics suggests there may be even greater accumulation than was previously suspected. A range of shallow water organisms are known to ingest microplastics, and the extent of their harmful effects will likely be influenced by their relative abundance. The discovery of substantial quantities in deep-sea sediments is of considerable relevance to our understanding of the potential of these particles to cause harm in the marine environment."

Source:  University of Plymouth
 
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