scholarly journals Biodiversity of Upwelling Coastal Systems of the Southern Caribbean Sea Adjacent to Guajira Peninsula

2021 ◽  
Vol 9 (8) ◽  
pp. 846
Author(s):  
Catalina Vasquez-Carrillo ◽  
Kathleen Sullivan Sealey

This paper describes the unique natural communities and biodiversity of the upwelling coastal system along the Guajira peninsula in the southern Caribbean Sea. The Guajira peninsula has a small human population with limited infrastructure and limited opportunities for coastal research, yet its coastal upwelling system is unique in the Tropical Western Atlantic region. This report includes both field observations along with a review of literature on the biodiversity of coastal eastern Guajira. In addition, it identifies missing information on the coastal system that is key to its management and conservation. Mangrove wetlands along with submerged aquatic vegetation (SAV) communities in a combination of consolidated and unconsolidated shorelines (e.g., rocky shores, cliffs, and beaches) form unique habitats in eastern Guajira. The diversity of these habitats is illustrated with the Bahia Hondita marine lagoon, where critical nursery habitat for several commercial valuable and endangered fisheries species, including sharks and sea turtles, is observed. Less information is available on more cryptic fauna, invertebrates, and coastal plankton species. Several anthropogenic factors are threatening species diversity in coastal Guajira, including overgrazing, mining, and target-species overfishing. Additional threats, such as extreme weather events (e.g., storms and droughts) as well as changes in coastal water quality, are also impacting species. The protection of the Guajira’s biodiversity would depend on local communities’ governance and empowerment as well as law enforcement for mining and agriculture operations. Management plans can include reducing land-based sources of pollution and building coastal resilience for climate change.

Zootaxa ◽  
2017 ◽  
Vol 4237 (1) ◽  
pp. 131 ◽  
Author(s):  
FABIO BETTINI PITOMBO ◽  
JUDITH GOBIN ◽  
NIVIA MARIA NUNES ABREU ◽  
ALANA JUTE

The barnacle Megabalanus zebra is largely known from ship hulls, with little information on its biology, ecology, and natural range. We identify M. zebra here from the southern Caribbean, based upon specimens collected as early as 2002. Challenges associated with identifying megabalinine species have delayed recognition of this species as distinct from other Caribbean Megabalanus. Sequenced material of M. zebra from Curaçao did not match M. zebra GenBank sequences that could be verified by descriptions or vouchered material. The presence of young M. zebra on vessels that have not left the Caribbean, as well as on pier pilings and resident buoys, indicate that this species is established in the tropical Western Atlantic Ocean, but the timing of its invasion remains unknown.  


Crustaceana ◽  
2017 ◽  
Vol 90 (7-10) ◽  
pp. 1279-1288 ◽  
Author(s):  
Bernd Werding ◽  
Alexandra Hiller

A new species of porcellanid crab from the southern Caribbean Sea is described. Pachycheles tuerkayi n. sp. has been confused with P. serratus (Benedict, 1901) since the 1950s because the two species are morphologically and ecologically similar and have overlapping distributions in the southern Caribbean. P. tuerkayi n. sp. is restricted to the coasts of Costa Rica, Panamá and Colombia. P. serratus ranges from Puerto Rico and the Virgin Islands to the coasts of Panamá, Colombia and Venezuela. Genetic differences based on DNA sequences of the mitochondrial 16S rDNA gene from the two species surpassed those estimated for geminate porcellanids on each side of the Isthmus of Panamá. Field observations where P. tuerkayi n. sp. and P. serratus overlap indicated that the two species come into contact when sharing the same substrate. The total number of porcellanid species in the western Atlantic rises to 50.


Zootaxa ◽  
2009 ◽  
Vol 2015 (1) ◽  
pp. 62-68 ◽  
Author(s):  
IVAN SAZIMA ◽  
ALFREDO CARVALHO-FILHO ◽  
JOÃO LUIZ GASPARINI ◽  
CRISTINA SAZIMA

A new species of scaly blenny, Labrisomus conditus sp. n., is described from Fernando de Noronha Archipelago, off northeastern Brazil. It differs from its Western Atlantic congeners by the following combination of characters: nuchal cirri when depressed not reaching dorsal-fin origin, 68 to 73 lateral line scales, first and second dorsal-fin spines slightly shorter than third spine and not flexible, numerous pale dots overall (light blue in life), opercular dark spot with incomplete and diffuse broad pale margin (orange in life). The new species is a territorial bottom-dweller in rocky shores and is found among algae and in crevices at depths from 0.5 to 6 m. Labrisomus conditus sp. n. feeds mostly on crustaceans (crabs, amphipods) and molluscs (snails, bivalves). The new species increases to five the species within the genus Labrisomus recorded from Southwestern Atlantic.


2021 ◽  
Author(s):  
Andrea Devis-Morales ◽  
Efraín Rodríguez-Rubio ◽  
Raúl Andrés Montoya-Sánchez

2013 ◽  
Vol 9 (2) ◽  
pp. 841-858 ◽  
Author(s):  
C. Giry ◽  
T. Felis ◽  
M. Kölling ◽  
W. Wei ◽  
G. Lohmann ◽  
...  

Abstract. Several proxy-based and modeling studies have investigated long-term changes in Caribbean climate during the Holocene, however, very little is known on its variability on short timescales. Here we reconstruct seasonality and interannual to multidecadal variability of sea surface hydrology of the southern Caribbean Sea by applying paired coral Sr/Ca and δ18O measurements on fossil annually banded Diploria strigosa corals from Bonaire. This allows for better understanding of seasonal to multidecadal variability of the Caribbean hydrological cycle during the mid- to late Holocene. The monthly resolved coral Δδ18O records are used as a proxy for the oxygen isotopic composition of seawater (δ18Osw) of the southern Caribbean Sea. Consistent with modern day conditions, annual δ18Osw cycles reconstructed from three modern corals reveal that freshwater budget at the study site is influenced by both net precipitation and advection of tropical freshwater brought by wind-driven surface currents. In contrast, the annual δ18Osw cycle reconstructed from a mid-Holocene coral indicates a sharp peak towards more negative values in summer, suggesting intense summer precipitation at 6 ka BP (before present). In line with this, our model simulations indicate that increased seasonality of the hydrological cycle at 6 ka BP results from enhanced precipitation in summertime. On interannual to multidecadal timescales, the systematic positive correlation observed between reconstructed sea surface temperature and salinity suggests that freshwater discharged from the Orinoco and Amazon rivers and transported into the Caribbean by wind-driven surface currents is a critical component influencing sea surface hydrology on these timescales.


2017 ◽  
Vol 14 (20) ◽  
pp. 4795-4813 ◽  
Author(s):  
Alexander Galán ◽  
Bo Thamdrup ◽  
Gonzalo S. Saldías ◽  
Laura Farías

Abstract. The upwelling system off central Chile (36.5° S) is seasonally subjected to oxygen (O2)-deficient waters, with a strong vertical gradient in O2 (from oxic to anoxic conditions) that spans a few metres (30–50 m interval) over the shelf. This condition inhibits and/or stimulates processes involved in nitrogen (N) removal (e.g. anammox, denitrification, and nitrification). During austral spring (September 2013) and summer (January 2014), the main pathways involved in N loss and its speciation, in the form of N2 and/or N2O, were studied using 15N-tracer incubations, inhibitor assays, and the natural abundance of nitrate isotopes along with hydrographic information. Incubations were developed using water retrieved from the oxycline (25 m depth) and bottom waters (85 m depth) over the continental shelf off Concepción, Chile. Results of 15N-labelled incubations revealed higher N removal activity during the austral summer, with denitrification as the dominant N2-producing pathway, which occurred together with anammox at all times. Interestingly, in both spring and summer maximum potential N removal rates were observed in the oxycline, where a greater availability of oxygen was observed (maximum O2 fluctuation between 270 and 40 µmol L−1) relative to the hypoxic bottom waters ( <  20 µmol O2 L−1). Different pathways were responsible for N2O produced in the oxycline and bottom waters, with ammonium oxidation and dissimilatory nitrite reduction, respectively, as the main source processes. Ammonium produced by dissimilatory nitrite reduction to ammonium (DNiRA) could sustain both anammox and nitrification rates, including the ammonium utilized for N2O production. The temporal and vertical variability of δ15N-NO3− confirms that multiple N-cycling processes are modulating the isotopic nitrate composition over the shelf off central Chile during spring and summer. N removal processes in this coastal system appear to be related to the availability and distribution of oxygen and particles, which are a source of organic matter and the fuel for the production of other electron donors (i.e. ammonium) and acceptors (i.e. nitrate and nitrite) after its remineralization. These results highlight the links between several pathways involved in N loss. They also establish that different mechanisms supported by alternative N substrates are responsible for substantial accumulation of N2O, which are frequently observed as hotspots in the oxycline and bottom waters. Considering the extreme variation in oxygen observed in several coastal upwelling systems, these findings could help to understand the ecological and biogeochemical implications due to global warming where intensification and/or expansion of the oceanic OMZs is projected.


2018 ◽  
Vol 29 (2) ◽  
Author(s):  
N. O. Roshchyna

In this article, the current and former distribution of higher aquatic vegetation has been analyzed for floodplain lakes, arenas lakes and third terraces lakes in the valleys of large and medium North-Steppe Dnieper rivers. The article is devoted to the current state analysis of the higher aquatic vegetation at North-Steppe Dnieper lakes, its dynamics over a long-term period, as well as the determination of the nature and extent of anthropogenic-climatic changes in vegetation. Anthropogenic influence is a major threat to the development and functioning of most aquatic ecosystems. Since the twentieth century, it has been intensified by trends to long-term climate changes, which are also largely result of human activity. Increasing temperature of the winter season does not contribute to snow accumulation. Reduction of snow accumulation (frequent thaws during the winter), regulation of river flow (formation of a reservoirs cascade and ponds) and accumulation of melt water in artificial reservoirs led to the smoothing of the peak of the spring flood. Thus, the factor that provided spring washing of floodplain lakes, limited their overgrowing by air-water vegetation and their waterlogging disappeared. The anthropogenic factors that influence negatively include: intensification of agriculture, plowing of coastal areas, unreasonable land reclamation, overgrazing, development of transport and engineering infrastructure, urbanization, recreation, and chemical pollution. The presented data was obtained on the basis of processing our own research materials of 2009–2018 and literary and archival materials analysis (the herbarium of the Dnipropetrovs’k National University and the archive of the Research Institute of Biology). Natural Northern Steppe Dnieper lakes are located mainly in river valleys, so the study area was conventionally divided into sections: the large river valley (Dnieper) and the middle rivers valleys (Samara and Orel). Three ecological groups of macrophytes were reviewed and compared: hydatofites (submerged species), pleistophytes (species with floating leaves) and helophytes (air-water species). The vegetation of Dnieper floodplain lakes practically did not change for all three formation groups. The number of immersed plants communities within the floodplains of medium-sized rivers has decreased by three. The pleistophytes and helophytes associations decreased to fragments of associations. The lakes vegetation within the sandy Dnieper terrace practically did not change for all three formation groups. The submerged lakes plants associations within the sandy medium-sized rivers terraces have been reduced by two. As part of the lakes vegetation on the Dnipro saline terraces, fragments of associations of the two species are considered extinct. A new association of southern adventive species Ruppia maritima L. has appeared within the limits of the middle rivers saline terrace. Changes in higher aquatic vegetation are characteristic of all types of lakes. Changes occur in the direction of crowding out higher aquatic vegetation communities by airborne plant communities. The consequence of the anthropogenic-climatic transformation of aquatic ecosystems is increased mineralization, siltation, and, as a result, intensive overgrowing of lakes by aboriginal and adventive species with a wide ecological amplitude (replacement of sensitive to environmental changes species).


2021 ◽  
Vol 145 (7-8) ◽  
pp. 311-321
Author(s):  
Damir Ugarković ◽  
Nenad Potočić ◽  
Marko Orešković ◽  
Krešimir Popić ◽  
Mladen Ognjenović ◽  
...  

Tree dieback is a complex process involving negative impact of various abiotic, biotic and anthropogenic factors. Climate change, comprising all those effects, is generally considered as the largest threat to forest ecosystems in Europe. Although the scale of climate change impacts on forests is not yet fully understood, especially on the regional or species level, significant damage seems to be caused by weather extremes, such as drought and strong winds. With the expected increase in the number, length, and/or intensity of extreme weather events in Croatia, research into the causes of tree mortality is both important and timely. Silver fir is the most damaged and endangered conifer tree species in Croatia. The dieback of silver fir can be attributed to various factors, therefore the goals of this research were to determine the mortality of silver fir trees (by number and volume) for various causes of mortality, among which the climatic and structural parameters were of most interest. The twenty-year data for tree mortality in pure silver fir stands in the area of Fužine (Gorski kotar, Croatia) were collected and analysed. The largest number and volume of dead trees was caused by complex (multiple causes) dieback in the overstorey (0,75 N/ha, 2,35 m<sup>3</sup>/ha), and the smallest (0,17 N/ha, 0,02 m<sup>3</sup>/ha) by dieback of supressed trees. No significant differences were determined regarding the timing of tree death for different causes of mortality. Climatic parameters (drought, air temperature, PET) and structural parameters of the stands (tree DBH, social position, crown diameter, shading, physiological maturity) as well as plot inclination were found to be the factors of a significant influence on the mortality of silver fir trees.


2008 ◽  
Vol 6 (2) ◽  
pp. 289-292 ◽  
Author(s):  
Peter J. Auster

Predators are known to modify hunting tactics in response to local conditions to exploit prey of different species, densities or position within habitat patches. I describe three unusual prey hunting tactics used by trumpetfish (Aulostomus maculatus) distributed in midwater above reefs off Bonaire, Netherlands Antilles, in the southern Caribbean Sea. Hunting behaviors were focused on dense feeding aggregations of brown chromis (Chromis multilineata) and were categorized as: (1) slow horizontal following, (2) vertical hovering or drift, and (3) diagonal cross encounters where trumpetfish descended diagonally through the water while adjusting trajectory to encounter target prey. Understanding variation in predator behavior and ambit, in this case vertical ambit, adds to our knowledge of how predators adapt to unique local opportunities to exploit prey.


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